FIELD
[0001] The present invention relates to a wireless communication system,
a wireless terminal, a wireless base station, and a wireless communication
method.
BACKGROUND
[0002] In recent years, in an attempt to further increase speed and
capacity of wireless communication in a wireless communication system, such as
a mobile phone system (cellular system), discussions are held on wireless
communication technology for the next generation. For example, in the 3GPP
(3rd generation partnership project), which is a standards organization, a
communication standard called as LTE (long term evolution) and a
communication standard called as LTE-A (LTE-advanced) based on the wireless
communication technique of LTE are suggested.
[0003] The latest communication standard completed in the 3GPP is
Release 10 compatible with LTE-A, in which Releases 8 and 9 compatible with
LTE are greatly functionally enhanced. Currently, discussions are held for
completion of Release 11, in which Release 10 is further enhanced. In the
descriptions below, "LTE" includes, in addition to LTE and LTE-A, other wireless
communication systems that are made by enhancing LTE unless otherwise
noted.
[0004] In Release 11 of the 3GPP, coordinated multiple point (CoMP) is
one of the techniques that are discussed actively in particular. Simply put,
CoMP is a technique to coordinate sending and receiving to a wireless terminal
(UE: user equipment) between different wireless base stations (eNB: evolved
node B). In the following descriptions, a wireless link in a direction from a
wireless terminal to a wireless base station is called as an uplink (UL) and a

wireless link in a direction from a wireless base station to a wireless terminal is
called as a downlink (DL).
[0005] There are several forms of CoMP, and a scenario is known in which
a wireless terminal carries out communication with different wireless base
stations for UL and DL. In a regular case, a wireless terminal carries out
communication with an identical wireless base station for UL and DL. That is, it
is common that a wireless terminal carries out communication with a connected
wireless base station (serving cell). As an example, a wireless terminal receives
UL scheduling information from a connected wireless base station on a DL and
sends data to the connected wireless base station on a UL based on the received
UL scheduling information. As another example, a wireless terminal receives
data from a connected wireless base station on a DL and sends a response signal
(ACK signal or NACK signal) to the received data to the connected wireless base
station on a UL.
[0006] However, there is sometimes another wireless base station whose
communication quality of UL for the wireless terminal is higher than the
connected wireless base station. Even when certain communication quality of
DL (receiving quality, propagation delay, and the like) is secured, in such a case
that a wireless terminal is located at a cell edge, the communication quality of UL
may not be good. When there is another wireless base station whose
communication quality of DL is higher than the connected wireless base station,
the connected wireless base station of the wireless terminal is switched by
handover, so that this is out of the problem.
[0007] Such problemeasily occurs as well in a so-called heterogeneous
network, for example, wheremacrocells, which are regular base stations, and
picocells and the like (also microcells, femtocells, and the like), which are small
base stations, are mixed. In a heterogeneous network, a picocell is desired to
suppress the DL cell size (suppress the sending power) in order to inhibit
interference in a macrocell. That is, a macrocell and a picocell greatly differ in
DL cell size (sending power). Therefore, a situation may occur that, for a

wireless terminal located at a cell edge of the connected macrocell, the DL
quality is better with a macrocell while the UL quality is better with a picocell.
[0008] In the 3GPP, in view of such problems, a scenario is under review
in which a wireless terminal carries out communication with different wireless
base stations for UL and DL as described above. In this scenario, when there is
another wireless base station whose communication quality of UL for a wireless
terminal is higher than the connected wireless base station, the wireless terminal
carries out UL communication with the base station different from the connected
wireless base station. As an example, it is possible that the wireless terminal
receives UL scheduling information from the connected wireless base station on
a DL and sends data to a base station different from the connected wireless base
station on a UL based on the received UL scheduling information. As another
example, it is possible that a wireless terminal receives data from the connected
wireless base station on a DL and sends a response signal to the received data to
a base station different from the connected wireless base station on a UL. In
such a manner, it becomes possible to secure the UL wireless communication
quality to a wireless terminal that has poor UL wireless quality with the
connected wireless base station. Then, as a result, an effect of improving
transmission efficiency of the entire system is expected.
[0009] Citation List
[0010] Non Patent Literature
[0011] NPL1: 3GPPTS36.211V10.4.0 (2011-12)
[0012] NPL2: 3GPPTS36.213 V10.4.0 (2011-12)
[0013] NPL3: 3GPP TR36.814 V9.0.0 (2010-03)
[0014] NPL 4: 3GPP TR36.819 V11.0.0 (2011-09)
[0015] NPL 5: 3GPP R1-114324 "On Reference Signal Enhancements for
UL CoMP"
SUMMARY
[0016] [TECHNICAL PROBLEM]

[0017] When a wireless terminal and a wireless base station carry out
communication, with some exceptions, scheduling of a wireless resource
(hereinafter, may be referred to simply as scheduling) is carried out.
Scheduling of a wireless resource is to determine a wireless resource that is used
for sending and receiving of a wireless signal (to assign a wireless resource or to
determine allocation of a wireless resource is synonymous). For example, a
wireless resource is defined by a time component and a frequency component.
Scheduling of a wireless resource is carried out by a connected wireless base
station to a subordinate wireless terminal. The connected wireless base station
notifies a connected wireless terminal of scheduling information related to the
determined scheduling on a DL, and the connected wireless terminal and the
wireless base station carry out sending and receiving of a wireless signal based
on the scheduling information.
[0018] Consideration is given to the above described scheduling in the
scenario where a wireless terminal carries out communication with different
wireless base stations for UL and DL. Now, it is assumed that a wireless
terminal is intended to send data on a UL. At this time, the wireless terminal
sends a signal that requests UL scheduling to the connected wireless base
station. Next, it is assumed that the connected wireless base station that has
received the signal that requests UL scheduling determines to cause another
wireless base station to receive UL data of the wireless terminal based on
receiving quality of the wireless signal from the wireless terminal and the like.
[0019] At this time, the connected wireless base station sends UL
scheduling information to the wireless terminal on a DL. The wireless terminal
sends a wireless signal including UL data using a UL wireless resource that is
specified by the received UL scheduling information.
[0020] Meanwhile, in parallel with the above, the connected wireless base
station sends the UL scheduling information also to another wireless base station
via a backhaul network (network that links between wireless base stations and a
wireless base station with a core network). The other wireless base station

receives a wireless signal including UL data from the wireless terminal using the
wireless resource that is specified by the received UL scheduling information.
[0021] According to the above consideration, in the scenario where a
wireless terminal carries out communication with different wireless base stations
for UL and DL, it may also be considered that scheduling is carried out without a
problem and the other wireless base station is capable of receiving data from the
wireless terminal. However, in such scenario, a phenomenon is confirmed in
which another wireless base station different from the connected base station is
sometimes not capable of receiving data from the wireless terminal.
[0022] [SOLUTION TO PROBLEM]
[0023] The disclosed technique has made in view of the above, and it is an
object thereof to provide a wireless communication system, a wireless terminal,
a wireless base station, and a wireless communication method that allow, when
a wireless terminal carries out communication with different wireless base
stations for UL and DL, another wireless base station different from the
connected base station to receive data from the wireless terminal.
[0024] [ADVANTAGEOUS EFFECTS OF INVENTION]
[0025] According to one embodiment of a wireless communication system,
a wireless terminal, a wireless base station, and a wireless communication
method disclosed herein, an effect is exhibited that, when a wireless terminal
carries out communication with different wireless base stations for UL and DL,
another wireless base station different from the connected base station is
capable of receiving data from the wireless terminal.
BRIEF DESCRIPTION OF DRAWINGS
[0026] FIG. 1 is a diagram illustrating problems in conventional techniques.
[0027] FIG. 2 is a diagram illustrating one example of a network
configuration of a wireless communication system in a first embodiment.
[0028] FIG. 3 is one example of a process sequence diagram of the
wireless communication system in the first embodiment.

[0029] FIG. 4 is a diagram illustrating one example of a DCI format in the
wireless communication system of the first embodiment.
[0030] FIG. 5 is one example of a functional configuration diagram of a
wireless base station in the wireless communication system of the first
embodiment.
[0031] FIG. 6 isone example of a functional configuration diagram of a
wireless terminal in the wireless communication system of the first embodiment.
[0032] FIG. 7 is one example of a hardware configuration diagram of the
wireless base station in the wireless communication system of the first
embodiment.
[0033] FIG. 8 is one example of a hardware configuration diagram of the
wireless terminal in the wireless communication system of the first embodiment.
[0034] FIG. 9 is one example of a process sequence diagram of a wireless
communication system in a second embodiment.
[0035] FIG. 10 is a diagram illustrating one example of a DCI format in the
wireless communication system of the second embodiment.
[0036] FIG. 11 is one example of a process sequence diagram of a wireless
communication system in a third embodiment.
[0037] FIG. 12 is one example of a process sequence diagram of a wireless
communication system in a fourth embodiment.
[0038] FIG. 13 is one example of a process sequence diagram of a wireless
communication system in a fifth embodiment.
[0039] FIG. 14 is one example of a process sequence diagram of a wireless
communication system in a sixth embodiment.
[0040] FIG. 15 is a diagram illustrating one example of a DCI format in a
wireless communication system of a seventh embodiment.
DESCRIPTION OF EMBODIMENTS
[0041] Descriptions are given below to embodiments of a wireless
communication system, a wireless terminal, a wireless base station, and a

wireless communication method of the disclosure, with reference to the
drawings. Although descriptions are given as separate embodiments for
convenience, it is of course possible to also obtain effects of combination by
combining respective embodiments and further enhance the usability.
[0042] [a] Identification of problem
[0043] As described above, in the scenario where a wireless terminal
carries out communication with different wireless base stations for UL and DL, a
phenomenon is confirmed in which another wireless base station different from
the connected base station is sometimes not capable of receiving data from the
wireless terminal. Keenly reviewing this phenomenon, the inventor has found
that there are problems of wireless resource scheduling in the scenario. Here,
before describing the respective embodiments, descriptions are given to
identification of the problems that the inventor has found.
[0044] As described above, a wireless terminal sends a wireless signal
including UL data (called as a first wireless signal) using a wireless resource that
is specified by UL scheduling information received from the connected wireless
base station. In contrast, another wireless base station receives a wireless
signal including UL data from the wireless terminal based on scheduling
information received from the connected wireless base station (that is, based on
a wireless resource defined by the connected wireless base station). However,
at this time, there is a possibility that the other wireless base station has already
sent the scheduling information specifying the wireless resource to another
wireless terminal connected thereto. This is because it is not possible for the
other wireless base station to predict a UL reception request from the connected
wireless base station in advance.
[0045] In such a case, the other wireless terminal sends a wireless signal
including data (called as a second wireless signal) to the other wireless base
station using the wireless resource specified by the UL scheduling information
received from the other wireless base station. Thus, the wireless terminal and
the other wireless terminal turn out to carry out UL sending using same wireless

resources (sending time, sending frequency). In other words, the first wireless
signal and the second wireless signal are sent on same wireless resources. As a
result, conflict occurs in a UL wireless resource. Since the first wireless signal
and the second wireless signal include different data and interfere with each
other, it becomes difficult forthe other wireless base station to decode any data.
Accordingly, in such a case, the other wireless base station turns out not to be
capable of receiving data without an error from the wireless terminal. FIG. 1
illustrates an outline of this problem.
[0046] To sum up above, in the scenario where a wireless terminal carries
out communication with different wireless base stations for UL and DL, conflict of
a wireless resource may occur in UL sending. Then, when conflict of a wireless
resource occurs in UL sending, it is not possible that another wireless base
station different from the connected base station receives data without an error
from the wireless terminal. Accordingly, in the scenario where a wireless
terminal carries out communication with different wireless base stations for UL
and DL, there is a problem that the other wireless base station is sometimes not
capable of receiving data from the wireless terminal.
[0047] In addition, when the other wireless base station is not capable of
receiving data without an error (not capable of decoding data), the wireless
terminal and the other wireless terminal turn out to carry out resending of data
in response to reception of a NACK signal or a timeout of a response signal.
Resending of data leads to a waste of wireless resources and thus is not
preferred.
[0048] The technique of the disclosure has been embodied based on the
findings of the above problems by the inventor.
[0049] [b] First embodiment
[0050] FIG. 2 illustrates a network configuration of a wireless
communication system in the first embodiment. The present embodiment is an
embodiment of a wireless communication system compliant with LTE.
Therefore, some of LTE specific terms and concepts appear. However, the

present embodiment is merely one example and it is noted that it is applicable to
a wireless communication system compliant with a communication standard
other than LTE.
[0051] The wireless communication system illustrated in FIG. 2 is provided
with a plurality of wireless base stations (eNB: evolved node B) la, lb, lc,
wireless terminals (UE: user equipment) 2a, 2b, and the like. In the
descriptions below, the plurality of wireless base stations la, lb, lc may be
represented collectively as wireless base stations 1. In addition, the plurality of
wireless terminals 2a, 2b may be represented collectively as wireless terminals 2.
[0052] Wireless networks between the wireless base stations and the
wireless terminals are called as wireless access networks. The wireless base
stations 1 are connected with a wired or wireless network (transmission network)
called as a backhaul network. A backhaul network is a network that links
between the wireless base stations 1 and the wireless base stations 1 with a core
network. The wireless base stations 1 are capable of carrying out
communication with a device connected to the core network via the backhaul
network. To the core network, an MME (mobility management entity), an SAE-
GW (system architecture evolution gateway), and the like that are not illustrated
are connected. An LTE network may also be called as an EPS (evolved packet
system). The EPS includes aeUTRAN (evolved universal terrestrial radio
network), which is a wireless access network, and an EPC (evolved packet core),
which is a core network. The core network may also be called as an SAE
(system architecture evolution).
[0053] The wireless base stations 1 (may also be called simply as base
stations) in FIG. 2 is a device that carries out wireless communication with the
wireless terminals 2 via the wireless access network and also is connected to the
backhaul network. The wireless base station la carries out sending and
receiving of data with the subordinate wireless terminal 2a (may be referred to
as a connected wireless terminal) and also carries out a variety of control over
the wireless terminal 2a by exchanging various types of control information with

the subordinate wireless terminal 2a. In addition, the wireless base station la
carries out relay of data with the other wireless base stations lb, lc, each other,
via the backhaul network and also is capable of cooperation by exchanging
various types of control information with the other wireless base stations lb, lc.
[0054] The wireless base stations 1 carries out exchange of a variety of
control information with a control device, such as an MME connected to the core
network beyond the backhaul network, via the backhaul network. In addition,
the wireless base station la relays the data received from the subordinate
wireless terminal 2a to a relay device, such as an SAE-GW connected to the core
network, and also relays the data received from the relay device, such as an
SAE-GW, to the subordinate wireless terminal 2a.
[0055] The wireless base stations 1 may be connected with the backhaul
network by wire and may also be connected wirelessly. In addition, the wireless
base stations 1 may also have a communication function with the wireless access
network as an extended RRH, which is a separate device, and connect by wire
therewith.
[0056] Although a "cell" is a range that the wireless base stations 1 covers
in order that the wireless terminals 2 sends and receives a wireless signal
(strictly, there are UL cells and DL cells), the wireless base stations 1 and the cell
are almost corresponding concepts, so that it does not matter if the "cell" and
the "wireless base station" are read interchangeably as appropriate in the
descriptions below.
[0057] Meanwhile, the wireless terminals 2 (may also be called simply as
terminals; may also be called as user devices, subscriber stations, mobile
stations, and the like) in FIG. 2 are devices that carry out wireless
communication with the wireless base stations 1 via the wireless access network.
The wireless terminal 2a is connected to one wireless base station la, and as a
change occurs in a wireless state by transfer and the like, the wireless base
station 1 to be connected is switched by handover. Here, while "connection"
indicates that a wireless terminal is registered in (attached to) a wireless base

station, it may also be interpreted to simply mean in communication. The
wireless base station la connected by the wireless terminal 2a is called as a
connected wireless base station or a serving cell. The wireless terminal 2a
carries out sending and receiving of data by wireless communication with the
connected wireless base station la and also is subject to a variety of control by
exchanging various types of control information by wireless communication with
the connected wireless base station la.
[0058] The wireless terminal 2a in the present embodiment receives a DL
wireless signal from the connected wireless base station la. The wireless
terminal 2a in the present embodiment is capable of sending a UL wireless signal
to the connected wireless terminal la or the other wireless base stations lb, lc.
Accordingly, the wireless terminal 2a in the present embodiment is capable of
carrying out communication with wireless base stations 1 different for DL and UL.
Details are described later.
[0059] The wireless communication system in the present embodiment
uses an OFDMA (orthogonal frequency division multiple access) scheme as a DL
wireless access scheme. In addition, it uses an SC-FDMA (single carrier
frequency division multiple access) scheme as an uplink wireless access scheme.
[0060] The wireless communication system in the present embodiment is
configured with, as well as a DL wireless signal and a UL wireless signal, a
wireless frame (may also be referred to simply as a frame) having a
predetermined length (for example, 10 milliseconds). Further, one wireless
frame is respectively configured with a predetermined number (for example, 10)
of wireless subframes (may also be referred to simply as subframes) having a
predetermined length (for example, 1 millisecond). Then, each subframe is
further divided into each physical channel, which is a physical communication
path. Since a "frame" and a "subframe" are merely terms that indicate
processing units of a wireless signal, these terms may also be read
interchangeably as appropriate in the following.

[0061] As a DL physical channel, there are a downlink shared channel
(PDSCH: physical downlink shared channel) that is used for transmission of a DL
data signal and the like, a downlink control channel (PDCCH: physical downlink
control channel) that is used for transmission of a DL control signal, and the like.
In a PDSCH, as well as a DL data signal, a DL reference signal for various types
of measurement and the like are also mapped. Meanwhile, as a UL physical
channel, there are an uplink shared channel (PUSCH: physical uplink shared
channel) that is used for transmission of a UL data signal and the like, an uplink
control channel (PUCCH: physical uplink control channel) that is used for
transmission of a UL control signal, and the like. In PUSCH, as well as a UL
data signal, a UL reference signal for various types of measurement and the like
are also mapped.
[0062] Next, based on FIG. 3, descriptions are given to a process sequence
of the wireless communication system in the first embodiment. FIG. 3 is a
process sequence when sending data (UL data) to the connected wireless base
station la occurs in the wireless terminal, 2a. As described before, the wireless
terminal 2a in the present embodiment is capable of receiving a DL wireless
signal from the connected wireless base station la and also sending a UL wireless
signal to the connected wireless base station la or the other wireless base
station lb, which is another wireless base station. That is, the wireless terminal
2a is capable of carrying out communication with wireless base stations 1
different for DL and UL. FIG. 3 is one example of such asymmetric wireless
communication.
[0063] In S101 in FIG. 3, UL data occurs in the wireless terminal 2a. For
example, UL data occurs when an audio signal, data, and the like are sent from
the wireless terminal 2a to the other wireless terminal 2b, when an application
on the wireless terminal 2a sends data to a server on the Internet, and the like.
As the UL data occurs, in S102, the wireless terminal 2a sends UL schedule
requesting information, which is information to requesta UL wireless resource in
order to send the UL data, to the connected wireless base station la on a UL

wireless signal. In the UL schedule requesting information, information
indicating a UL wireless resource amount to be used (UL wireless resource
amount information) is stored.
[0064] As receiving the UL schedule requesting information, the connected
wireless base station la starts scheduling of a UL wireless resource to the
wireless terminal 2a. The connected wireless base station la firstly obtains, for
example, UL receiving quality from the wireless terminal 2a. It is possible to
obtainthe UL receiving quality based on a sound reference signal (SRS) included
in the UL wireless signal. Then, the connected wireless base station la decides
whether the obtained UL receiving quality satisfies a predetermined criterion.
Based on this decision, in S103, the connected wireless base station la
determines whether or not to set a base station to receive UL data as a local
station (connected wireless base station la). When the receiving quality
satisfies the predetermined criterion, the connected wireless base station la
determines the base station to receive UL data as the local station (connected
wireless base station la). In contrast, when the receiving quality does not
satisfy a predetermined criterion, the connected wireless base station la
determines the base station to receive UL data as any of the other wireless base
stations lb, lc other than the local station (at this time point, the other wireless
base stations lb, lc do not have to be determined into one). This is because,
when the UL receiving quality from the wireless terminal 2a in the connected
wireless base station la is poor, it is possible to secure communication efficiency
of the entire system more by causing the UL data from the wireless terminal 2a
to be received by the other wireless base stations lb, lc.
[0065] Although the connected wireless base station la in this example
carries out determination of whether or not to receive at a local station in S103
based on the UL receiving quality, instead of or in addition to this, the
determination may also be carried out based on another index. For example,
when the UL wireless resource use amount or activity rate of the local station is
not less than the predetermination (when there are less space in the UL wireless

resource), it is possible that the connected wireless base station la determines
the base station to receive UL data as other than the local station.
[0066] Back to the description of FIG. 3, in this example, it is assumed that
the connected wireless base station la determines, in S103, the base station to
receive UL data as other than the local station (connected wireless base station
la). At this time, in S104, the connected wireless base station la sends
wireless resource requesting information, which is information to requesta UL
wireless resource to the other wireless base stations 1b, lc via the transmission
network. Here, the connected wireless base station 1a is capable of carrying
out selection of a sending destination of the wireless resource requesting
information based on, for example, DL receiving quality of each wireless base
station stored in a measurement report, not illustrated, that is successively
received from the wireless terminal 2a. The other wireless base stations lb, lc
to be the sending destination of wireless resource requesting information may be
one or a plurality, and in the example of FIG. 3, it is assumed that two other
wireless base stations lb, lc are selected as the sending destination.
[0067] In S105 in FIG. 3, as receiving the wireless resource requesting
information respectively, the other wireless base stations lb, lc obtain unused
wireless resources. Here, for example, an unused wireless resource in the other
wireless base station lb is a UL wireless resource that the other wireless base
station lb does not cause any subordinate wireless terminal 2b to use for UL
sending (not to be scheduled for UL sending). In other words, even when the
wireless terminal 2a subordinate to the connected wireless base station la
carries out UL sending using an unused wireless resource to the other wireless
base station lb, resource conflict turns out not to occur. Since the other
wireless base station lb controls and manages schedules of all subordinate
wireless terminals 2b, it is possible to obtain the unused wireless resources
easily. In S106, the other wireless base stations lb, lc respectively send other
station wireless resource information including unused wireless resources

information that indicates the obtained unused wireless resources to the
connected wireless base station la via the transmission network.
[0068] The connected wireless base station la receives the other station
wireless resource information including the unused wireless resources
information respectively from the other wireless base stations 1b, 1c. Then, in
S107, the connected wireless base station la determinesa UL wireless resource
(referred to as a determined wireless resource) that is used for UL sending from
the subordinate wireless terminal 2a and the other wireless base station
(referred to as a determined wireless base station) to be a sending destination of
the UL sending based on the received unused wireless resources information.
Here, it is assumed that the magnitude of the determined wireless resources is
not less than the UL wireless resource amount requested in the UL schedule
requesting information from the wireless terminal 2a. In S107, the connected
wireless base station la is capable of determining the determined wireless
resource and the determined wireless base station by an arbitrary criterion based
on the unused wireless resources indicated by the unused wireless resources
information. For example, it is possible that the connected wireless base station
la selects arbitrary one from the unused wireless resources capable of securing
the requested UL wireless resource amount to determine the determined wireless
resource therefrom. Then, the connected wireless base station la is capable of
setting the other wireless base station lb that has sent the selected unused
wireless resource (information) as the determined wireless base station. Here,
it is assumed that the connected wireless base station la determines the
determined wireless resource from the unused wireless resources that the other
wireless base station lb has sent and determines the other wireless base station
lb as the determined wireless base station.
[0069] In S108, the connected wireless base station la sends information
indicating the determined wireless resource determined in S107 (referred to as
determined wireless resource information) to the subordinate wireless terminal
2a on a DL wireless signal. Here, this DL wireless signal includes DCI (data

control information), which is a DL control signal defined by LTE. DCI is a DL
control signal including control information, such as information related to data
scheduling, used by the wireless terminal 2a for sending and receiving of data.
There are several formats in DCI, and a control object is different depending on
the format. For example, format 0 in DCI is to control over the PUDCH, that is,
UL data. Formats 1A, 1B, 1C, 1, 2 are respectively to control over the PDSCH,
that is, DL data.
[0070] FIG. 4 illustrates one example of a DCI format in the first
embodiment. The DCI illustrated in FIG. 4 is defined by LTE, and it is used as is
in the first embodiment. The DCI in FIG. 4 includes an RNTI (radio network
temporary identifier), which is an identifier of a DCI destination (wireless
terminal 2a), RB assignment (resource block assignment), which is information
indicating the wireless resource having data allocated thereto (to which resource
block (RB) on the wireless frame data is assigned), and MCS (modulation and
coding scheme), which indicates modulation and coding scheme of data.
Although DCI includes, as well as these, parameters, such as an RV (redundancy
version), an NDI (new data indicator), a HARQ (hybrid automatic repeat request)
processing number, and PUCCH power control, details are omitted.
[0071] In the present embodiment, the determined wireless resource
information corresponds to the RB assignment of DCI. That is, in S108, the
connected wireless base station la in the present embodiment sends the
determined wireless resource information to the subordinate wireless terminal 2a
by sending the DCI on a DL wireless signal. In contrast, in S108, the wireless
terminal 2a receives the DL wireless signal including the DCI that includes the
determined wireless resource information (RB assignment). At this time, the
wireless terminal 2a recognizes (detects) the DCI towards itself based on the
RNTI included in the DCI. In addition, the wireless terminal 2a recognizes
(detects) that the DCI targets the UL data based on the DCI format.
[0072] In S109 in FIG. 3, the connected wireless base station la sends the
determined wireless resource information to the other wireless base station lb,

which is the determined wireless base station determined in S107 via the
transmission network. The connected wireless base station la in the present
embodiment sends the determined wireless resource information to the other
wireless base station lb, which is the determined wireless base station, by
sending the DCI in S109. Here, S108 and S109 may also be simultaneous or
opposite in order. This completes scheduling of UL wireless sending from the
subordinate wireless terminal 2a to the other wireless base station lb by the
connected wireless base station la. When the connected wireless base station
la determines the base station to receive UL data as the local station in S103,
regular UL wireless resource scheduling may be carried out, so that the
description is omitted.
[0073] Subsequently, in S110 in FIG. 3, the wireless terminal 2a sends a
UL wireless signal including the UL data using the UL wireless resource indicated
by the received determined wireless resource information (RB assignment of
DCI). At this time, the wireless terminal 2a carries out coding and modulation
of the UL data based on an MCS included in the DCI received in S108. In
contrast, in S110, the other wireless base station lb receives the UL wireless
signal sent by the wireless terminal 2a using the UL wireless resource indicated
by the received determined wireless resource information. At this time, the
other wireless base station lb carries out demodulation and decoding of the UL
data based on the MCS included in the DCI received in S109. Lastly, in Sill,
the other wireless base station lb sends (transfers) the UL data included in the
received UL wireless signal to the connected wireless base station la via the
transmission network. This completes reception of the UL data in S112.
[0074] As described above, in the wireless communication system of the
first embodiment, the connected wireless base station la receives the other
station wireless resource information including the unused wireless resources
information, which is information indicating UL wireless resources not used by
the other wireless base station lb, from the other wireless base station 1b.
Then, the connected wireless base station la schedules the UL wireless resource

used for UL sending from the subordinate wireless terminal 2a to the other
wireless base station 1b based on the received unused wireless resources
information. Thus, it is possible to avoid conflict in the UL wireless resource
between the UL sending from the wireless terminal 2a subordinate to the
connected wireless base station la to the other wireless base station lb and the
UL sending from another wireless terminal 2a subordinate to the other wireless
base station lb to the other wireless base station 1b. Accordingly, according to
the wireless communication system in the first embodiment, when the wireless
terminal 2a carries out communication with different wireless base stations for
UL and DL, it is possible that the other wireless base station different from the
connected base station receives data from the wireless terminal. In addition, as
a result, it is possible to achieve efficient utilization of wireless resources.
[0075] Next, based on FIG. 5 and FIG. 6, descriptions are given to
functional configuration of each device in the first embodiment in order.
[0076] FIG. 5 is a diagram illustrating one example of functional
configuration of the wireless base station 1 in the first embodiment. The
wireless base station 1 is provided with, for example, a UL wireless receiving unit
101, a UL frame analysis unit 102, a UL reference signal processing unit 103, a
UL control signal demodulation and decoding unit 104, a UL data signal
demodulation and decoding unit 105, a scheduler unit 106, a DL data signal
generation unit 107, a DL data signal coding and modulation unit 108, a DL
control signal generation unit 109, a DL control signal coding and modulation
unit 110, a DL reference signal generation unit 111, a DL frame generation unit
112, a DL wireless sending unit 113, a transmission network sending unit 114,
and a transmission network receiving unit 115.
[0077] Firstly, descriptions are given to each of these functions in the
connected wireless base station la of the first embodiment.
[0078] The UL wireless receiving unit 101 receives a UL wireless signal,
downconverts the received wireless signal by frequency conversion and the like
for conversionto a baseband signal corresponding to a UL frame, and outputs it

to the UL frame analysis unit 102. The UL frame analysis unit 102 extracts a UL
data signal, a UL control signal, and a UL reference signal from the baseband
signal corresponding to the UL frame. At this time, the UL frame analysis unit
102 carries out extraction of each signal based on UL scheduling information
(information equivalent to RB assignment of DCI) inputted from the scheduler
unit 106. Then, the UL frame analysis unit 102 outputs the UL reference signal
to the UL reference signal processing unit 103, outputs the UL control signal to
the UL control signal demodulation and decoding unit 104, and outputs the UL
data signal to the UL data signal demodulation and decoding unit 105.
[0079] The UL reference signal processing unit 103 obtains UL channel
characteristics based on a demodulation reference signal (DM-RS) among the UL
reference signal and inputs them to the UL control signal demodulation and
decoding unit 104 and the UL data signal demodulation and decoding unit 105.
In addition, the UL reference signal processing unit 103 obtains UL receiving
quality based on a sounding reference signal (SRS), which is a reference signal
for scheduling, among the UL reference signal and inputs it to the scheduler unit
106.
[0080] The UL control signal demodulation and decoding unit 104
demodulates the UL control signal to carry out error correction and decoding.
The UL control signal demodulation and decoding unit 104 carries out
demodulation and decoding of the UL control signal using the UL channel
characteristics inputted from a UL reference signal generation unit 212 and
predetermined modulation scheme and error correction and coding scheme.
The UL control signal demodulation and decoding unit 104 inputs the
demodulated and decoded UL control signal to the scheduler unit 106. As
examples of the UL control signal, there are UL schedule requesting information,
a UL response signal (ACK/NACK signal) to DL data, and the like.
[0081] The UL data signal demodulation and decoding unit 105
demodulates the UL data signal to carry out error correction and decoding. The
UL data signal demodulation and decoding unit 105 carries out demodulation and

decoding of the UL data signal using the UL channel characteristics inputted from
the UL reference signal generation unit 212 and the modulation scheme and the
error correction and coding scheme inputted from the scheduler unit 106. The
UL data signal demodulation and decoding unit 105 inputs the demodulated and
decoded UL data signal to the scheduler unit 106.
[0082] Descriptions are given to the scheduler unit 106 in the present
embodiment. The scheduler unit 106 carries out scheduling of a wireless
resource used for wireless communication and also carries out a variety of
control associated with the scheduling of a wireless resource. The scheduler
unit 106 schedules respective UL and DL wireless resources. As a first example,
when UL schedule requesting information, which is one item of the UL control
information sent by the wireless terminal 2a, is inputted from the UL control
signal demodulation and decoding unit 104, the scheduler unit 106 schedules a
UL wireless resource to the wireless terminal 2a. As a second example, in such
a case that a DL schedule requisition is inputted from an upper layer unit 206 (a
case that data has to be sent to the wireless terminal 2a on a DL), the scheduler
unit 106 schedules a DL wireless resource.
[0083] Here, when scheduling a UL wireless resource to the wireless
terminal 2a, the scheduler unit 106 in the present embodiment selectively
determines the wireless base station 1 to be a UL sending destination. In other
words, the scheduler unit 106 in the present embodiment is capable of selecting
the other wireless base stations lb, lc other than the local station (wireless base
station la) as the UL sending destination. Of course, it goes without saying that
the scheduler unit 106 may also select the local station (wireless base station la)
as the UL sending destination. The scheduler unit 106 may employ a variety of
methods in determination of the wireless base station 1 to be the UL sending
destination of the wireless terminal 2a and determination of the UL wireless
resource to be assigned to the wireless terminal 2a. The scheduler unit 106
may also carry out these determinations collectively and may also carry out them
in order.

[0084] Descriptions are given to scheduling of a UL wireless resource when
the scheduler unit 106 in the present embodiment selects the other wireless base
station lb as the UL sending destination from the wireless terminal 2a. In this
case, the scheduler unit 106 has to avoid the conflict in a UL wireless resource
described above. With that, when selecting the other wireless base station lb
as the UL sending destination, the scheduler unit 106 obtains information related
to the UL wireless resource used by the wireless terminal 2a subordinate to the
other wireless base station lb (hereinafter, may also be referred to as other
station wireless resource information). This point is one of the processes that
conventional techniques do not perform, so that detailed descriptions are given
below.
[0085] Descriptions are given to contents of the other station wireless
resource information in the present embodiment. The contents of the other
station wireless resource information may be, as an example, information
indicating a UL wireless resource not used by the other wireless base station lb
(referred to as unused wireless resources information). The unused wireless
resources information is, so to speak, information indicating a wireless resource
where resource conflict does not occur even when being used by the wireless
base station la (even when being scheduled as the UL wireless resource used in
UL sending from the wireless terminal 2a subordinate to the wireless base station
la to the other wireless base station lb). It becomes possible to avoid UL
resource conflict by that the scheduler unit 106 of the connected wireless base
station la selectively determines the UL wireless resource to be assigned to the
subordinate wireless terminal 2a from the unused wireless resources information
received from the other wireless base station lb.
[0086] The unused wireless resources information is merely one example
of the other station wireless resource information. As another example of the
other station wireless resource information, information indicating a UL wireless
resource used by the other wireless base station lb (referred to as used wireless
resource information) is also available. The used wireless resource information

is, so to speak, information indicating a wireless resource where resource conflict
occurs when being used by the wireless base station la (when being scheduled
as the UL wireless resource used in the UL sending from the wireless terminal 2a
subordinate to the wireless base station to the other wireless base station lb).
It becomes possible to avoid UL resource conflict by that the scheduler unit 106
of the wireless base station la selectively determines the UL wireless resource to
be assigned to the subordinate wireless terminal 2a from the UL wireless
resource other than the used wireless resource information received from the
other wireless base station lb.
[0087] Descriptions are given to a procedure where the connected wireless
base station la of the present embodiment obtains the other station wireless
resource information from the other wireless base stations lb, lc. In the
procedure where the wireless base station obtains the other station wireless
resource information, the scheduler unit 106 carries out, for example, sending of
requesting information (referred to as wireless resource requesting information)
that requests other station wireless resource information to the other wireless
base stations lb, lc. Specifically, it goes as follows, for example. Firstly, when
the UL receiving quality inputted from the UL reference signal unit is lower than
a predetermined value, the scheduler unit 106 determines to send wireless
resource requesting information. Next, the scheduler unit 106 sends wireless
resource requesting information to the other wireless base stations lb, lc
(adjacent wireless base or peripheral wireless base station). The other wireless
base stations lb, lc to be the sending destination may be one or may also be a
plurality. In addition, it is possible to carry out the selection of the other
wireless base stations lb, lc to be the sending destination based on, for
example, DL receiving quality information for each wireless base station that is
stored in a measurement report received from the wireless terminal 2a. As
receiving the wireless resource requesting information, the other wireless base
stations lb, lc send other station information including the other station wireless
resource information to the connected wireless base station la in response to

the wireless resource requesting information. Thus, the scheduler unit 106 of
the wireless base station la is capable of obtaining the other station wireless
resource information from the other wireless base stations lb, 1c. There are
other examples considered as the procedure where the connected wireless base
station la obtains other station wireless resource information from the other
wireless base stations lb, lc, and they are described later (described in a fourth
embodiment through a sixth embodiment).
[0088] As receiving the other station wireless resource information from
the other wireless base stations lb, leas described above, the scheduler unit 106
carries out UL scheduling to the subordinate wireless terminal 2a based on the
other station wireless resource information. Specifically, the scheduler unit 106
determines the determined wireless resource, which is the UL wireless resource
used for the UL sending from the subordinate wireless terminal 2a, and the
determined wireless base station, which is the other wireless base station lb to
be the sending destination of the UL sending, based on the unused wireless
resources information included in the received other station wireless resource
information. Here, it is assumed that the magnitude of the determined wireless
resources is not less than the UL wireless resource amount requested in the UL
schedule requesting information from the wireless terminal 2a. The scheduler
unit 106 is capable of determining the determined wireless resource and the
determined wireless base station by an arbitrary criterion based on the unused
wireless resources indicated by the unused wireless resources information. For
example, it is possible that the scheduler unit 106 selects arbitrary one from the
unused wireless resources capable of securing the requested UL wireless
resource amount to determine the determined wireless resource therefrom.
Then, the scheduler unit 106 is capable of setting the other wireless base station
lb that has sent the selected unused wireless resource (information) as the
determined wireless base station.
[0089] As described above, the scheduler unit 106 carries out scheduling
of the UL wireless resource to the wireless base station lb from the wireless

terminal 2a when the other wireless base station lb is selected as the UL
sending destination from the wireless terminal 2a. After that, in order, to
generate a DCI, the scheduler unit 106 inputs the UL scheduling result to the DL
control signal generation unit 109. The UL scheduling result is information
including a wireless resource for UL sending (the above determined wireless
resource), an identifier of the wireless terminals la, a coding and modulation
scheme of a signal, and the like. In addition, when selecting the other wireless
base station lb, the scheduler unit 106 also inputs the UL scheduling result to
the transmission network sending unit 114. Further in this case, the scheduler
unit 106 inputs base station identification information indicating the UL receiving
other wireless base station lb (corresponding to the determined wireless base)
to the transmission network sending unit 114.
[0090] In contrast, when selecting the local station as the UL sending
destination from the wireless terminal 2a, the scheduler unit 106 carries out
general UL scheduling (the description is omitted). Then, in order to generate a
DCI, the scheduler unit 106 inputs the UL scheduling result to the DL control
signal generation unit 109. For the preparation of UL reception at the local
station, the scheduler unit 106 inputs the UL scheduling result to the UL frame
analysis unit 102.
[0091] Meanwhile, when DL data occurs, the scheduler unit 106 schedules
DL sending. In this case, the scheduler unit 106 carries out general DL
scheduling (the description is omitted). In order to generate a DCI, the
scheduler unit 106 inputs the DL scheduling result to the DL control signal
generation unit 109. The DL scheduling result is information including a
wireless resource for DL sending, an identifier of the wireless terminal la, a
coding and modulation scheme of a signal, and the like. In addition, the
scheduler unit 106 inputs DL data to the DL data signal generation unit 107.
[0092] Back to the descriptions in FIG. 5, as the DL data is inputted from
the scheduler unit 106, the DL data signal generation unit 107 generates a DL
data signal and inputs it to a DL data coding and modulation unit. The DL data

coding and modulation unit codes and modulates the DL data signal based on
the coding scheme and the modulation scheme inputted from the scheduler unit
106 and inputs it to the DL frame generation unit 112.
[0093] A DL control information generation unit generates DL control
information based on the scheduling result inputted from the scheduler unit 106
and inputs it to the DL control signal coding and modulation unit 110. As an
example, the DL control signal generation unit 109 generates the DCI described
before based on the inputted scheduling result. The DL control signal
generation unit 109 sets an RB assignment value of the DCI based on the
determined wireless resource included in the scheduling result inputted from the
scheduler unit 106. In addition, the DL control signal generation unit 109 sets
the wireless terminal identifier inputted from the scheduler as an RNTI value and
sets the modulation scheme and the coding scheme as an MCS value. The DL
control signal generation unit 109 inputs the generated DL control signal to the
DL control signal coding and modulation unit 110.
[0094] The DL control signal coding and modulation unit 110 codes and
modulates the DL control signal based on the predetermined modulation scheme
and coding scheme and inputs it to the DL frame generation unit 112. The DL
reference signal generation unit 111 generates the DL reference signal and
inputs it to the DL frame generation unit 112.
[0095] The DL frame generation unit 112 places (also called as maps) the
DL data signal, the DL control signal, and the DL reference signal after coding
and modulation in a DL frame and generates a DL frame. The DL frame
generation unit 112 carries out mapping of each DL signal using the DL
scheduling result inputted from the scheduler unit 106. That is, the DL frame
generation unit 112 carries out mapping of each signal to the wireless resource
(RB) defined in the DL scheduling result inputted from the scheduler unit 106.
The DL frame generation unit 112 inputs the baseband signal corresponding to
the generated DL frame to the DL wireless sending unit 113.

[0096] The DL wireless sending unit 113upconverts the baseband signal
corresponding to the inputted DL frame to a wireless signal by frequency
conversion and the like and wirelessly sends the wireless signal to the wireless
terminal 2a.
[0097] The transmission network sending unit 114 sends a data signal and
a control signal to the other wireless base stations lb, lc, other control devices,
relay devices, and the like via the backhaul network. As an example, when the
scheduler unit 106 selects other than the local station as the UL sending
destination, the transmission network sending unit 114 sends the wireless
resource requesting information described above to the other wireless base
stations lb, lc. The sending of the wireless resource requesting information is
carried out by accepting an input of base station identifiers indicating the other
wireless base stations lb, lc from the scheduler unit 106. As an example, when
the scheduler unit 106 selects the other wireless base station lb as the UL
sending destination, the transmission network sending unit 114 sends the
determined wireless resource information described above to the other wireless
base station lb. The sending of the determined wireless resource information is
carried out by accepting an input of the UL scheduling result and the base
station identifier from the scheduler unit 106.
[0098] The transmission network receiving unit 115 receives a data signal
and a control signal from the other wireless base stations lb, lc, other control
devices, relay devices, and the like via the backhaul network. For example,
when the scheduler unit 106 selects other than the local station as the UL
sending destination, the transmission network receiving unit 115 receives the
other station wireless resource information described before from the other
wireless base stations lb, lc. The transmission network receiving unit 115
inputs the received other station wireless resource information to the scheduler
unit 106.
[0099] Next, descriptions are given to the other wireless base station lb in
the first embodiment (the other wireless base station lc is similar).

[00100] Although the other wireless base station lb also has a functional
configuration same as FIG. 5, different process is carried out in a part of the
functions. It goes without saying that the respective wireless base stations 1
may be provided with both a function provided in the connected wireless base
station la and a function provided in the other wireless base station lb. In
other words, the respective wireless base stations are capable of behaving as the
connected wireless base station to a certain wireless terminal and behaving as
another wireless base station to another wireless terminal.
[00101] The transmission network receiving unit 115 of the other wireless
base station lb receives a data signal and a control signal from the connected
wireless base station la, other control devices, relay devices, and the like
connected to the backhaul network. As an example, when the connected
wireless base station la selects other than the local station (connected wireless
base station la) as the UL sending destination from the subordinate wireless
terminal 2a, the transmission network receiving unit 115 receives the wireless
resource requesting information described before from the connected wireless
base station la. The transmission network receiving unit 115 inputs the
received wireless resource requesting information to the scheduler unit 106. As
another example, the transmission network receiving unit 115 receives the
determined wireless resource information described before from the connected
wireless base station la. The transmission network receiving unit 115 inputs
the received determined wireless resource assignment information to the
scheduler unit 106.
[00102] The scheduler unit 106 of the other wireless base station lb
generates other station wireless resource information based on the inputted
wireless resource requesting information. In the present embodiment, as
described before, the other station wireless resource information includes the
unused wireless resources information, which is information indicating UL
resources not used by the other wireless base station lb. The scheduler unit
106 generates the unused wireless resources information as follows.

[00103] The scheduler unit 106 of the other wireless base station lb
subjectively and also fully determines scheduling of each wireless terminal 2b
subordinate to the other wireless base station lb. Therefore, the scheduler unit
106 recognizes fixed scheduling (wireless resource to be used) in the present
and future of each subordinate wireless terminal 2b. In addition, the scheduler
unit 106 is also capable of controlling not to use a certain wireless resource in
the future (not to use a certain frequency range in a certain period).
Accordingly, the scheduler unit 106 of the other wireless base station lb is
capable of recognizing a wireless resource not used by the local station (other
wireless base station lb), in other words, a wireless resource not to be
scheduled for the subordinate wireless terminal 2b by the local station. With
that, the scheduler unit 106 of the other wireless base station lb selects a part
or all of the wireless resources not used by the local station to set information
indicating the selected wireless resource as the unused wireless resources
information. Then, the scheduler unit 106 generates other station wireless
resource information including the unused wireless resources information. The
scheduler unit 106 inputs the generated other station wireless resource
information to the transmission network sending unit 114.
[00104] In addition, the scheduler unit 106 of the other wireless base
station lb carries out scheduling to accept the UL sending from the wireless
terminal 2a subordinate to the connected wireless base station la based on the
determined wireless resource information received from the connected wireless
base station la. The determined wireless resource information is determined by
the connected wireless base station la based on the unused wireless resources
information sent earlier, and is information indicating a part or all of the UL
wireless resource indicated by the unused wireless resources information. The
scheduler unit 106 inputs the UL scheduling result that reflects the received UL
resource assignment information to the UL frame analysis unit 102. The UL
frame analysis unit 102 extracts respective information from the UL frame based
on the UL scheduling result. Thus, it becomes possible that the other wireless

base station lb receives data on a UL from the wireless terminal 2a subordinate
to the connected wireless base station la.
[00105] When the connected wireless base station la selects the other
wireless base station lb as the UL sending destination, the transmission network
«
sending unit 114 of the other wireless base station lb in the present
embodiment sends the other station wireless resource information including the
unused wireless resources information to the connected wireless base station la.
The sending is carried out by accepting an input of the other station wireless
resource information from the scheduler unit 106.
[00106] Next, descriptions are given to the wireless terminal 2a in the first
embodiment.
[00107] FIG. 6 is a diagram illustrating one example of a functional
configuration of the wireless terminals 2a in the first embodiment. The wireless
terminal 2a is provided with, for example, a DL wireless receiving unit 201, a DL
frame analysis unit 202, a DL reference signal processing unit 203, a DL control
signal demodulation and decoding unit 204, a DL data signal demodulation and
decoding unit 205, an upper layer unit 206, a UL schedule management unit 207,
a UL data signal generation unit 208, a UL data signal coding and modulation
unit 209, a UL control signal generation unit 210, a UL control signal coding and
modulation unit 211, a UL reference signal generation unit 212, a UL frame
generation unit 213, and a UL wireless sending unit 214.
[00108] The DL wireless receiving unit 201 receives a DL wireless signal,
downconverts the received wireless signal by frequency conversion and the like
to convert it to a baseband signal corresponding to the DL frame, and outputs it
to the DL frame analysis unit 202. The DL frame analysis unit 202 extracts a DL
data signal, a DL control signal, and a DL reference signal from the baseband
signal corresponding to the DL frame. Then, the DL frame analysis unit 202
outputs the DL reference signal to the DL reference signal processing unit 203,
outputs the DL control signal to the DL control signal demodulation and decoding

unit 204, and outputs the DL data signal to the DL data signal demodulation and
decoding unit 205.
[00109] The DL reference signal processing unit 203 of the wireless terminal
2a estimates DL channel characteristics based on the DL reference signal and
outputs the DL channel characteristics respectively to the DL control signal
demodulation and decoding unit 204 and the DL data signal demodulation and
decoding unit 205.
[00110] The DL control signal demodulation and decoding unit 204
demodulates the DL control signal and extracts DL control information by
carrying out error correction and decoding. The DL control signal demodulation
and decoding unit 204 carries out demodulation and decoding of the DL control
signal using the DL channel characteristics and predetermined demodulation
scheme and error correction and decoding scheme. As obtaining the DCI, which
is the DL control information, by demodulation- and decoding, the DL control
signal demodulation and decoding unit 204 recognizes (detects) a DCI towards
itself based on the RNTI included therein. The DL control signal demodulation
and decoding unit 204 recognizes (detects) whether the scope of DCI application
is UL data (PUSCH) or DL data (PDSCH) based on the DCI format. Regarding
the DCI towards itself that targets the DL data, the DL control signal
demodulation and decoding unit 204 inputs the RB assignment and the MCS
included in the DCI to the DL data signal demodulation and decoding unit 205.
Regarding the DCI towards itself that targets the UL data, the DL control signal
demodulation and decoding unit 204 inputs the RB assignment and the MCS
included in the DCI to the UL schedule management unit 207.
[00111] The DL data signal demodulation and decoding unit 205
demodulates the DL data signal and extracts DL data information by carrying out
error correction and decoding. In the DL data signal, one or more items of data
information to the wireless terminal 2a are multiplexed. The DL data signal
demodulation and decoding unit 205 carries out extraction of a DL data signal
towards itself using the RB assignment inputted from the DL control signal

demodulation and decoding unit 204. After that, the DL data signal
demodulation and decoding unit 205 carries out demodulation and decoding of
the DL data signal based on the DL channel characteristics and the MCS inputted
from the DL control signal demodulation and decoding unit 204. The DL data
signal demodulation and decoding unit 205 inputs the obtained DL data to the
upper layer unit 206.
[00112] The upper layer unit 206 processes the inputted DL data to provide
various functions in the wireless terminal 2a. Although there are, for example, a
voice call, a web browser, a mailer, and the like as the functions provided by the
upper layer unit 206, there may also be other arbitrary functions. The upper
layer unit 206 generates UL data (information) based on the functions to be
provided and inputs them to the UL schedule management unit 207.
[00113] The UL schedule management unit 207 carries out management of
the UL schedule when UL data occurs. This is carried out as follows. As UL
data is inputted from the upper layer unit 206, the UL schedule management unit
207 inputs an instruction signal that is to send UL wireless resource requesting
information, which is one of the UL control signal, to the connected wireless base
station la to the UL control signal generation unit 210 for the purpose of
securing the UL wireless resource in a resource amount to be used for the UL
data. With respect to the UL wireless resource requesting information, the
connected wireless base station la notifies the wireless terminal 2a of the UL
wireless resource by the DCI, which is a DL control signal. After that, as
described before, regarding the DCI towards itself that targets the UL data, the
DL control signal demodulation and decoding unit 204 inputs the RB assignment
and the MCS included in the DCI to the UL schedule management unit 207. As
they are inputted, the UL schedule management unit 207 inputs the UL data
inputted earlier to the UL data signal generation unit 208 for the purpose of
carrying out UL data sending. Further, the UL schedule management unit 207
inputs the inputted MCS to the data signal coding and modulation unit and also
inputs the RB assignment to the UL frame generation unit 213.

[00114] The UL data signal generation unit 208 generates a UL data signal
based on the inputted UL data information and inputs it to the UL data signal
coding and modulation unit 209. The UL data signal coding and modulation unit
209 makes error correction and coding and modulation of the inputted UL data
signal based on the MCS inputted from the UL schedule management unit 207
and inputs it to the UL frame generation unit 213.
[00115] The UL control information generation unit generates UL control
information based on the instruction signal inputted from the UL schedule
management unit 207 and the like and inputs it to the UL control signal coding
and modulation unit 211. As examples of the UL control signal, there are UL
schedule requesting information to requesta UL wireless resource to the
connected wireless base station la when UL data occurs, a response signal
(ACK/NACK signal) to DL data, and the like. The UL control signal coding and
modulation unit 211 makes error correction and coding and modulation of the UL
control signal inputted from the UL control signal generation unit 210 based on a
predetermined modulation scheme and a coding scheme and inputs it to the UL
frame generation unit 213.
[00116] The UL reference information generation unit generates UL
reference information based on the instruction from the UL schedule
management unit 207 and inputs it to the UL frame generation unit 213. UL
reference signals include, as described before, a DM-RS (demodulation reference
signal) and a SRS (surrounding reference signal).
[00117] The UL frame generation unit 213 places (maps) the UL data signal,
the UL control signal, and the UL reference signal in a UL frame and generates a
UL frame. The UL frame generation unit 213 carries out mapping of each signal
using the RB assignment inputted from the UL schedule management unit 207.
The UL frame generation unit 213 inputs a baseband signal corresponding to the
generated UL frame to a wireless sending unit. The wireless sending
unitupconverts the baseband signal corresponding to the inputted UL frame by

frequency conversion and the like to a wireless signal for wireless sending of the
wireless signal to the wireless base station 1.
[00118] Next, based on FIGs. 7 and 8, descriptions are given to a hardware
configuration of each device in the wireless communication system of the first
embodiment.
[00119] FIG. 7 illustrates one example of a hardware configuration of the
wireless base station 1 in the present embodiment. Each function of the
wireless base stations 1 described before are achieved by a part or all of the
hardware components below. The wireless base station 1 in an embodiment is
provided with a wireless IF (interface) 11, an analog circuit 12, a digital circuit
13, a processor 14, a memory 15, a transmission network IF 16, and the like.
[00120] The wireless IF 11 is an interface device to carry out wireless
communication with the wireless terminals 2 and is, for example, an antenna.
The analog circuit 12 is a circuit to process an analog signal and may be roughly
categorized into those carrying out receiving process, those carrying out sending
process, and those carrying out other process. The analog circuit that carries
out receiving process includes, for example, a low noise amplifier (LIMA), a band
pass filter (BPF), a mixer, a low pass filter (LPF), an automatic gain control
amplifier (AGC: automatic gain controller), an analog-to-digital converter (ADC),
a phase locked loop (PLL), and the like. The analog circuit that carries out
sending process includes, for example, a power amplifier (PA), a BPF, a mixer,
an LPF, a digital-to-analog converter (DAC), a PLL, and the like. The analog
circuit that carries out other process includes a duplexer and the like. The
digital circuit 13 is a circuit to process a digital signal and includes, for example,
an LSI (large scale integration), an FPGA (field-programming gate array), an
ASIC (application specific integrated circuit), and the like. The processor 14 is a
device to process data and includes, for example, a CPU (central processing
unit), a DSP (desital signal processor), and the like. The memory 15 is a device
to memorize data and includes, for example, a ROM (read only memory), a RAM
(random access memory), and the like. The transmission network IF 16 is an

interface device to be connected to the backhaul network of the wireless
communication system by a wired link or a wireless link and to carry out wired
communication or wireless communication with a device on a transmission
network side including another wireless base station 1 connected to the backhaul
network or the core network.
[00121] Descriptions are given to correspondence relationship of the
functional configuration and the hardware configuration of the wireless base
station 1.
[00122] The UL wireless receiving unit 101 is achieved by, for example, the
wireless IF 11 and the analog circuit 12 (those carrying out receiving process).
That is, the wireless IF 11 receives a UL wireless signal from the wireless
terminal 2a, and the analog circuit 12 downconverts the received wireless signal
by frequency conversion and the like to convert it to a baseband signal
corresponding to a UL frame. The UL frame analysis unit 102 is achieved by,
for example, the processor 14, the memory 15, and the digital circuit 13. That
is, the processor 14 controls the memory 15 as occasion calls, cooperates with
the digital circuit 13 as occasion calls, and extracts a UL data signal, a UL control
signal, and a UL reference signal from the baseband signal corresponding to the
UL frame. In addition, the digital circuit 13 may also extract a UL data signal, a
UL control signal, and a UL reference signal from the baseband signal
corresponding to the UL frame.
[00123] The UL reference signal processing unit 103 is achieved by, for
example, the processor 14, the memory 15, and the digital circuit 13. That is,
the processor 14 controls the memory 15 as occasion calls, cooperates with the
digital circuit 13 as occasion calls, obtains the UL channel characteristics based
on the DM-RS, and obtains the UL receiving quality based on the SRS. In
addition, the digital circuit 13 may also obtain the UL channel characteristics
based on the DM-RS and obtain the UL receiving quality based on the SRS.
[00124] The UL control signal demodulation and decoding unit 104 is
achieved by, for example, the processor 14, the memory 15, and the digital

circuit 13. That is, the processor 14 controls the memory 15 as occasion calls,
cooperates with the digital circuit 13 as occasion calls, demodulates a UL control
signal, and carries out error correction and decoding. In addition, the digital
circuit 13 may also demodulate a UL control signal and carry out error correction
and decoding. The UL data signal demodulation and decoding unit 105 is
achieved by, for example, the processor 14, the memory 15, and the digital
circuit 13. That is, the processor 14 controls the memory 15 as occasion calls,
cooperates with the digital circuit 13 as occasion calls, demodulates a UL data
signal, and carries out error correction and decoding. In addition, the digital
circuit 13 may also demodulate a UL data signal and carry out error correction
and decoding.
[00125] The scheduler unit 106 is achieved by, for example, the processor
14, the memory 15, and the digital circuit 13. That is, the processor 14 controls
the memory 15 as occasion calls, cooperates with the digital circuit 13 as
occasion calls, and carries out scheduling of the wireless resource used for
wireless communication, and also carries out a variety of control associated with
the scheduling of the wireless resource. In addition, the digital circuit 13may
also carry out scheduling of the wireless resource used for wireless
communication and also carry out a variety of control associated with the
scheduling of the wireless resource.
[00126] The DL data signal generation unit 107 is achieved by, for example,
the processor 14, the memory 15, and the digital circuit 13. That is, the
processor 14 controls the memory 15 as occasion calls, cooperates with the
digital circuit 13 as occasion calls, and generates a DL data signal. In addition,
the digital circuit 13 may also generate a DL data signal. The DL data coding
and modulation unit is achieved by, for example, the processor 14, the memory
15, and the digital circuit 13. That is, the processor 14 controls the memory 15
as occasion calls, cooperates with the digital circuit 13 as occasion calls, and
codes and modulates a DL data signal. In addition, the digital circuit 13 may
also code and modulate a DL data signal. The DL control information

generation unit is achieved by, for example, the processor 14, the memory 15,
and the digital circuit 13. That is, the processor 14 controls the memory 15 as
occasion calls, cooperates with the digital circuit 13 as occasion calls, and
generates DL control information. In addition, the digital circuit 13 may also
generate DL control information. The DL data coding and modulation unit is
achieved by, for example, the processor 14, the memory 15, and the digital
circuit 13. That is, the processor 14 controls the memory 15 as occasion calls,
cooperates with the digital circuit 13 as occasion calls, and codes and modulates
a DL control signal. In addition, the digital circuit 13 may also code and
modulate a DL control signal. The DL reference signal generation unit 111 is
achieved by, for example, the processor 14, the memory 15, and the digital
circuit 13. That is, the processor 14 controls the memory 15 as occasion calls,
cooperates with the digital circuit 13 as occasion calls, and generates a DL
reference signal. In addition, the digital circuit 13 may also generate a DL
reference signal. The DL frame generation unit 112 is achieved by, for
example, the processor 14, the memory 15, and the digital circuit 13. That is,
the processor 14 controls the memory 15 as occasion calls, cooperates with the
digital circuit 13 as occasion calls, places the DL data signal, the DL control
signal, and the DL reference signal after coding and modulation in a DL frame,
and generates a DL frame. In addition, the digital circuit 13 may also place the
DL data signal, the DL control signal, and the DL reference signal after coding
and modulation in a DL frame and generate a DL frame.
[00127] The DL wireless sending unit 113 is achieved by, for example, the
wireless IF 11 and the analog circuit 12 (those carrying out sending process).
That is, the analog circuit 12upconverts a baseband signal corresponding to the
inputted DL frame by frequency conversion and the like to a wireless signal, and
the wireless IF 11 wirelessly sends the wireless signal to the wireless terminals 2.
While the DL wireless sending unit 113 and the UL wireless receiving unit 101
may be achieved by different wireless IFs 11 (antennas), they may also share
one wireless IF 11 by using a duplexer, which is the analog circuit 12.

[00128] The transmission network sending unit 114 is achieved by, for
example, the transmission network IF 16, the analog circuit 12, the processor 14,
the memory 15, and the digital circuit 13. That is, the processor 14 controls the
memory 15 as occasion calls, cooperates with the digital circuit 13 as occasion
calls, and converts a data signal and a control signal to be sent to a digital
baseband signal. In addition, the analog circuit 12 converts the digital
baseband signal to a wired signal or a wireless signal, and the transmission
network IF 16 sends the wired signal or the wireless signal. The transmission
network receiving unit 115 is achieved by, for example, the transmission network
IF 16, the analog circuit 12, the processor 14, the memory 15, and the digital
circuit 13. That is, the transmission network IF 16 receives the wired signal or
the wireless signal, and the analog circuit 12 converts the wired signal or the
wireless signal to a digital baseband signal. In addition, the processor 14
controls the memory 15 as occasion calls, cooperates with the digital circuit 13
as occasion calls, and converts a digital baseband signal to a data signal and a
control signal.
[00129] FIG. 8 illustrates one example of a hardware configuration of the
wireless terminal 2 in the first embodiment. Each function of the wireless
terminals 2 described before is achieved by a part or all of the hardware
components below. The wireless terminal 2 in the above embodiment is
provided with a wireless IF 21, an analog circuit 22, a digital circuit 23, a
processor 24, a memory 25, an input IF 26, an output IF 27, and the like.
[00130] The wireless IF 21 is an interface device to carry out wireless
communication with the wireless base stations 1 and is, for example, an
antenna. The analog circuit 22 is a circuit to process an analog signal and may
be roughly categorized into those carrying out receiving process, those carrying
out sending process, and those carrying out other process. The analog circuit
that carries out receiving process includes, for example, an LNA, a BPF, a mixer,
an LPF, an AGC, an ADC, a PLL, and the like. The analog circuit that carries out
sending process includes, for example, a PA, a BPF, a mixer, an LPF, a DAC, a

PLL, and the like. The analog circuit that carries out other process includes a
duplexer and the like. The digital circuit 23 includes, for example, an LSI, an
FPGA, an ASIC, and the like. The processor 24 is a device to process data and
includes, for example, a CPU, a DSP, and the like. The memory 25 is a device
to memorize data and includes, for example, a ROM, a RAM, and the like. The
input IF 26 is a device to carry out an input and includes, for example, an
operation button, a microphone, and the like. The output IF 27 is a device to
carry out an output and includes, for example, a display, a speaker, and the like.
[00131] Descriptions are given to correspondence relationship of the
functional configuration and the hardware configuration of the wireless terminal
2.
[00132] The DL wireless receiving unit 201 is achieved by, for example, the
wireless IF 21 and the analog circuit 22 (those carrying out receiving process).
That is, the wireless IF 21 receives a DL wireless signal from the wireless base
station 1, and the analog circuit 22downconverts the received wireless signal by
frequency conversion and the like to convert it to a baseband signal
corresponding to a DL frame. The DL frame analysis unit 202 is achieved by,
for example, the processor 24, the memory 25, and the digital circuit 23. That
is, the processor 24 controls the memory 25 as occasion calls, cooperates with
the digital circuit 23as occasion calls, and extracts a DL data signal, a DL control
signal, and a DL reference signal from the baseband signal corresponding to the
DL frame. In addition, the digital circuit 23 may also extract a DL data signal, a
DL control signal, and a DL reference signal from the baseband signal
corresponding to the DL frame.
[00133] The DL reference signal processing unit 203 is achieved by, for
example, the processor 24, the memory 25, and the digital circuit 23. That is,
the processor 24 controls the memory 25as occasion calls, cooperates with the
digital circuit 23as occasion calls, and obtains the DL channel characteristics
based on the DL reference signal. In addition, the digital circuit 23 may also
obtain the DL channel characteristics based on the DL reference signal.

[00134] The DL control signal demodulation and decoding unit 204 is
achieved by, for example, the processor 24, the memory 25, and the digital
circuit 23. That is, the processor 24 controls the memory 25 as occasion calls,
cooperates with the digital circuit 23 as occasion calls, demodulates a DL control
signal, and carries out error correction and decoding. In addition, the digital
circuit 23 may also demodulate a DL control signal and carry out error correction
and decoding. The DL data signal demodulation and decoding unit 205 is
achieved by, for example, the processor 24, the memory 25, and the digital
circuit 23. That is, the processor 24 controls the memory 25as occasion calls,
cooperates with the digital circuit 23as occasion calls, demodulates a DL data
signal, and carries out error correction and decoding. In addition, the digital
circuit 23 may also demodulate a DL data signal and carry out error correction
and decoding.
[00135] The upper layer unit 206 is achieved by, for example, the processor
24, the memory 25, and the digital circuit 23. That is, the processor 24 controls
the memory 25 as occasion calls, cooperates with the digital circuit 23 as
occasion calls, processes the inputted DL data, provides various functions in the
wireless terminal 2a, and also generates UL data (information) based on the
provided functions. In addition, the digital circuit 23 may also process the
inputted DL data, provide various functions in the wireless terminal 2a, and also
generate UL data (information) based on the provided functions. The UL
schedule management unit 207 is achieved by, for example, the processor 24,
the memory 25, and the digital circuit 23. That is, the processor 24 controls the
memory 25 as occasion calls, cooperates with the digital circuit 23 as occasion
calls, and carries out management of a UL schedule when UL data occurs. In
addition, the digital circuit 23 may also carry out management of a UL schedule
when UL data occurs.
[00136] The UL data signal generation unit 208 is achieved by, for example,
the processor 24, the memory 25, and the digital circuit 23. That is, the
processor 24 controls the memory 25 as occasion calls, cooperates with the

digital circuit 23 as occasion calls, and generates a UL data signal. In addition,
the digital circuit 23 may also generate a UL data signal. The UL data coding
and modulation unit is achieved by, for example, the processor 24, the memory
25, and the digital circuit 23. That is, the processor 24 controls the memory 25
as occasion calls, cooperates with the digital circuit 23 as occasion calls, and
codes and modulates a UL data signal. In addition, the digital circuit 23 may
also code and modulate a UL data signal. The UL control information
generation unit is achieved by, for example, the processor 24, the memory 25,
and the digital circuit 23. That is, the processor 24 controls the memory 25 as
occasion calls, cooperates with the digital circuit 23 as occasion calls, and
generates UL control information. In addition, the digital circuit 23 may also
generate UL control information. The UL data coding and modulation unit is
achieved by, for example, the processor 24, the memory 25, and the digital
circuit 23. That is, the processor 24 controls the memory 25 as occasion calls,
cooperates with the digital circuit 23 as occasion calls, and codes and modulates
a UL control signal. In addition, the digital circuit 23 may also code and
modulate a UL control signal. The UL reference signal generation unit 212 is
achieved by, for example, the processor 24, the memory 25, and the digital
circuit 23. That is, the processor 24 controls the memory 25 as occasion calls,
cooperates with the digital circuit 23 as occasion calls, and generates a UL
reference signal. In addition, the digital circuit 23 may also generate a UL
reference signal. The UL frame generation unit 213 is achieved by, for example,
the processor 24, the memory 25, and the digital circuit 23. That is, the
processor 24 controls the memory 25 as occasion calls, cooperates with the
digital circuit 23 as occasion calls, places the UL data signal, the UL control
signal, and the UL reference signal after coding and modulation in a UL frame,
and generates a UL frame. In addition, the digital circuit 23 may also place the
UL data signal, the UL control signal, and the UL reference signal after coding
and modulation in a UL frame and generate a UL frame.

[00137] The UL wireless sending unit 214 is achieved by, for example, the
wireless IF 21 and the analog circuit 22 (those carrying out sending process).
That is, the analog circuit 22upconverts a baseband signal corresponding to the
inputted UL frame by frequency conversion and the like to a wireless signal, and
the wireless IF 21 wirelessly sends the wireless signal to the wireless terminals 2.
While the UL wireless sending unit 214 and the DL wireless receiving unit 201
may be achieved by different wireless IFs 21 (antennas), they may also share
one wireless IF 21 by using a duplexer, which is the analog circuit 22.
[00138] As have been described based on FIGs. 2 through 8, in the wireless
communication system in the first embodiment, the connected wireless base
station la receives other station wireless resource information including unused
wireless resources information, which is information indicating a UL wireless
resource not used by the other wireless base station lb from the other wireless
base station lb. Then, the connected wireless base station la schedules a UL
wireless resource used for UL sending from the subordinate wireless terminal 2a
to the other wireless base station lb based on the received unused wireless
resources information. Thus, it is possible to avoid conflict in a UL wireless
resource between UL sending from the wireless terminal 2a subordinate to the
connected wireless base station la to the other wireless base station lb and UL
sending from another wireless terminal 2a subordinate to the other wireless base
station lb to the other wireless base station lb. Accordingly, according to the
wireless communication system in the first embodiment, when the wireless
terminal 2a carries out communication with different wireless base stations for
UL and DL, it is possible that the other wireless base station lb different from
the connected base station la receives data from the wireless terminal 2a. In
addition, as a result, it is possible to achieve efficient utilization of a wireless
resource.
[00139] [c] Second embodiment
[00140] In the second embodiment, descriptions are given to an example
other than the first embodiment when the wireless terminal 2a carries out

communication with wireless base stations 1 different for DL and UL. In the
second embodiment, descriptions are given to a case where sending data (DL
data) to the subordinate wireless terminal 2a occurs in the wireless base station
la.
[00141] In the second embodiment, there are many points in common with
the first embodiment. In the following descriptions, descriptions are given
mainly to the points different from the first embodiment in the second
embodiment.
[00142] Based on FIG. 9, descriptions are given to a process sequence in
the second embodiment. FIG. 9 corresponds to process, as described before,
where sending data (DL data) to the subordinate wireless terminal 2a occurs
inthe wireless base station la.
[00143] In S201 in FIG. 9, firstly, DL data occurs in the connected wireless
base station la. For example, DL data occurs when an audio signal, data, and
the like are sent from the other wireless terminal 2b to the subordinate wireless
terminal 2a, a server on the Internet sends data to the wireless terminal 2a, and
the like.
[00144] In S202, as DL data occurs, the connected wireless base station la
schedules a DL wireless resource to send the DL data to the wireless terminal 2a.
Here, the scheduling of a DL wireless resource may use a general technique, so
that the descriptions are omitted here.
[00145] Next, the connected wireless base station la schedules a UL
wireless resource to receive a response signal (ACK/NACK signal) from the
wireless terminal 2a that have received the DL data. This is carried out as
below. The connected wireless base station la obtains the UL receiving quality
from the wireless terminal 2a and determines whether or not to set a reception
destination of the response signal as the local station based on the UL receiving
quality in S203. In S204, as determining the base station to receive the UL data
as any of the wireless base stations 1 other than the local station, the connected
wireless base station la sends wireless resource requesting information to the

other wireless base stations lb, lc via the transmission network. In contrast,
the other wireless base stations lb, lc respectively obtain unused wireless
resources in S205, and send other station wireless resource information including
the unused wireless resources information to the connected wireless base station
la via the transmission network in S206. Then, it is assumed that, in S207, the
connected wireless base station la determines a UL wireless resource for the
response signal and the other wireless base station lb to be the UL sending
destination. S203 through S207 are similar to S103 through S107, so that the
details are omitted.
[00146] In S208 in FIG. 9, next, the connected wireless base station la
sends determined wireless resource information, which is information indicating
the selected UL wireless resource, to the subordinate wireless terminal 2a on a
DL wireless signal. At this time, the connected wireless base station la in the
second embodiment sends, in addition to the determined wireless resource
information, DL data on a DL wireless signal as well.
[00147] Here, once leaving from FIG. 9, which is a process sequence of the
second embodiment, descriptions are given to process when the connected
wireless base station la sends DL data in a conventional LTE system. As
scheduling a DL wireless resource to be assigned to DL data, the connected
wireless base station la places (maps) the DL data in the DL wireless resource
(resource block) on the DL frame. Together with this, the connected wireless
base station la places a DCI (refer to FIG. 4), which is DL control information, in
a predetermined region of the DL frame same as the DL data. As illustrated in
FIG. 4, the DCI includes RB assignment, which is information indicating the DL
wireless resource assigned to the DL data. Then, the connected wireless base
station la sends a DL wireless signal including the DL frame to the wireless
terminal 2a.
[00148] The descriptions for the conventional LTE system are continued.
The wireless terminal 2a receives a DL wireless signal including the DL frame.
The wireless terminal 2a recognizes (detects) the presence of DL data towards

itself based on the RNTI included in the DCI in the DL frame, and recognizes
(detects) that the scope of DCI application is the DL data (PDSCH) based on the
DCI format. Further, the wireless terminal 2a extracts the DL data based on the
RB assignment included in the DCI and carries out demodulation and decoding of
the DL data based on the MCS included in the DCI. The wireless terminal 2a
sends a response signal (an ACK signal indicating decoding success or a NACK
signal indicating decoding failure) to the connected wireless base station la on a
UL frame in accordance with the decoding result.
[00149] At this time, the wireless terminal 2a places the response signal in
the UL frame corresponding to the placement of the DCI itself in the DL frame
received earlier (note that it is not the placement indicated by the RB assignment
in the DCI). Thus, the connected wireless base station la is capable of easily
linking the sent DL data with the received response signal.
[00150] Specifically, the following specifications are defined in the LTE.
Resource specification in the PUCCH (logical channel for a UL control signal) is
carried out by a CCE (control channel element) number of the PDCCH (logical
channel for a DL control signal) represented by a formula (1). In other words,
specification of the UL wireless resource for ACK/NACK is carried out by
placement of the DCI resource represented by a formula (1).
[00151] [Math 1]

[00153] Here, Po is an antenna port, nccE is a minimum CCE number used
for sending of the corresponding DCI (for example, minimum CCE number upon
configuring the PDCCH), and NPUCCH(1) is a parameter notified by an upper layer.
Although a CCE is a wireless resource unit that a RB is divided further, details are
omitted.
[00154] Accordingly, in the conventional LTE system, the DL control
»
information (DCI) related to the DL data and the UL control information
(ACK/NACK) are only capable of using a mutually corresponding wireless

resource. Accordingly, regarding control information related to the DL data,
when the other wireless base station lb uses a certain UL wireless resource Rl,
for example, the connected wireless base station la is not only incapable of
using the UL wireless resource Rl (to avoid resource conflict) but also incapable
of using a DL wireless resource Rl. Even in a situation where the DL resources
do not interfere with each other, the connected wireless base station la in this
example has no option but to use a UL wireless resource R2 (* Rl) and a DL
wireless resource R2. Accordingly, in the conventional LTE system, scheduling
for control information related to the DL data may be considered to be poor in
flexibility.
[00155] With that, in the present embodiment, it is made possible to
separate the correspondence relationship of the DL control information (DCI)
related to DL data and the UL control information (ACK/NACK) and to allow
assignment of a wireless resource that does not correspond mutually.
Therefore, in the DCI, which is the DL control information, a region to store an
offset in the placement (mapping) from the corresponding UL control information
(referred to as a resource offset) is provided. Then, the wireless terminal 2a
having received the DL data as well as the DCI places a response signal to the
DL data in a wireless resource that is shifted by the resource offset stored in the
DCI from the corresponding wireless resource of the DCI.
[00156] FIG. 10 illustrates one example of a DCI format according to the
second embodiment. The DCI format in FIG. 10 includes the resource offset.
The resource specification using the resource offset may be represented as a
formula (2).
[00157] [Math 2]

[00159] Here, nCcE is a resource offset of the PUCCH, and the unit is a CCE.
[00160] In such a manner, in the wireless communication system in the
second embodiment, it is possible to assign a non-corresponding wireless

resource to the DL control information (DCI) related to the DL data and the UL
control information (ACK/NACK). For example, when the other wireless base
station lb uses a certain UL wireless resource Rl and a DL wireless resource Rl,
the connected wireless base station la is capable of using a UL wireless resource
R2 (= Rl + resource offset) and the DL wireless resource Rl. Accordingly, in
the wireless communication system in the present embodiment, it becomes
possible to carry out flexible scheduling for the control information related to the
DL data.
[00161] Back to the descriptions of FIG. 9, in S208, the connected wireless
base station la sends the DCI, which is DL control information, and the DL frame
including the DL data to the wireless terminal 2a. The DCI includes, in addition
to the resource offset described before, the RNTI, the RB assignment related to
the DL data, the MCS, and the like. Here, this resource offset corresponds to
the determined wireless resource information (UL wireless resource for UL
sending from the wireless terminal 2a to other wireless base station lb).
[00162] In contrast, in S208, the wireless terminal 2a receives the DL frame
sent by the connected wireless base station la. The wireless terminal 2a
recognizes (detects) the presence of the DL data towards itself based on the
RNTI included in the DCI in the DL frame, and recognizes (detects) that the
scope of DCI application is the DL data (PDSCH) based on the DCI format.
Further, the wireless terminal 2a extracts DL data based on RB assignment
included in the DCI, and carries out demodulation and decoding of the DL data
based on the MCS included in the DCI. Thus, in S209, the reception of DL data
is completed. The resource offset included in the DCI is to be used when
sending a UL control signal (ACK/NACK) and is not used here.
[00163] In S210 in FIG. 9, the connected wireless base station la sends
determined wireless resource information to the other wireless base station lb,
which is a sending source of the unused wireless resource to be the origin of the
determined wireless resource via the transmission network. Here, the
determined wireless resource information sent by the connected wireless base

station la corresponds to information indicating placement of adding the
resource offset included in the DCI to the placement of the DCI included in the
DL frame sent by the connected wireless base station la. S208 and S210 may
be simultaneous or in the reverse order.
[00164] This completes the scheduling of the UL wireless resource to the
wireless terminal 2a by the connected wireless base station la. In S203, when
the connected wireless base station la determines the local station as the base
station to receive UL data, regular UL wireless resource scheduling may be
carried out (details are omitted).
[00165] In S211 in FIG. 9, in response to the decoding result of S208, the
wireless terminal 2a sends a UL wireless signal including the UL frame where a
response signal (ACK signal indicating decoding success or NACK signal
indicating decoding failure), which is a UL control signal, is placed. At this time,
the wireless terminal 2a of the present embodiment places a response signal in a
UL frame using the resource offset included in the DCI as described before.
Specifically, the wireless terminal 2a has placement of the response signal in the
UL frame as placement where the resource offset included in the DCI is added to
the placement of the DCI itself in the DL frame received earlier.
[00166] In contrast, in S211, the other wireless base station lb receives a
response signal, which is a UL control signal placed in the UL frame included in
the UL wireless signal sent by the wireless terminal 2a. At this time, in S210,
the other wireless base station lb receives a response signal using the UL
wireless resource indicated by the determined wireless resource information
received from the connected wireless base station la. As described before, the
determined wireless resource information received from the connected wireless
base station la is the information indicating placement where the resource offset
included in the DCI is added to the placement of the DCI included in the DL
frame sent by the connected wireless base station la.
[00167] Lastly, in S212, the other wireless base station lb sends (transfers)
the response signal included in the received UL wireless signal to the connected

wireless base station la via the transmission network. This completes the
reception of a response signal (ACK/NACK) in the connected wireless base
station la in S213.
[00168] As described above based on FIGs. 9 and 10, in the wireless
communication system of the second embodiment, correspondence relationship
related to the placement of the DL control information (DCI) related to the DL
data and the UL control information (ACK/NACK) is separated and sends the
information related to the placement of the corresponding UL control information
in the DL control information. Thus, the wireless communication system in the
second embodiment exhibits, in addition to the effect obtained in the wireless
communication system in the first embodiment, an effect of allowing flexible
scheduling to the control information related to the DL data.
[00169] The functional configuration and the hardware configuration of the
respective device in the second embodiment follow those in the first
embodiment, so that the description is omitted.
[00170] [d] Third embodiment
[00171] The third embodiment is a modification that is applicable to the first
embodiment or the second embodiment, and the connected wireless base station
la selects the other wireless base station lb, which is a UL sending destination,
based on the UL receiving quality notified in advance from the other wireless
base stations lb.
[00172] In the following descriptions, descriptions are given to a
modification where the third embodiment is applied to the first embodiment.
Since this modification has many points in common with the first embodiment,
descriptions are given mainly to the points different from the first embodiment in
the following descriptions. As described before, although the third embodiment
may be modified by applying to the second embodiment, it may be applied
similarly to that to the first embodiment and the details are omitted.
[00173] Based on FIG. 11, descriptions are given to a process sequence of a
modification where the third embodiment is applied to the first embodiment.

Since S301 through S303 in FIG. 11 are similar toSlOl through S103 in FIG. 3,
the description is omitted. In S304, the connected wireless base station la
sends, in addition to wireless resource requesting information (similar to S104 in
FIG. 3), SRS resource information to the other wireless base stations lb, lc.
Here, the SRS resource information indicates resource information to be used for
reception of an SRS, which is a UL reference signal for UL receiving quality
measurement generated by the wireless terminal 2a. The SRS resource
information includes, for example, an RB to which an SRS is assigned, data series
information of an SRS, and the like. Since the generated SRS is different for
each wireless terminal 2, only the connected wireless base station la that
regularly recognizes the SRS resource information is capable of receiving it. By
obtaining the SRS resource information, the other wireless base stations lb, lc
become capable of receiving an SRS.
[00174] In S305 in FIG. 11, the other wireless base stations lb, lc confirm
a used wireless resource (similar to S105 in FIG. 3). Next, in S306, the other
wireless base stations lb, lc receive an SRS from the wireless terminal 2a using
the SRS resource information and measures the UL receiving quality. Then, in
S307, the other wireless base stations lb, lc send, in addition to the other
station wireless resource information (similar to S106 in FIG. 3), the UL receiving
quality information measured in S306 to the connected wireless base station la.
[00175] In S308 in FIG. 11, the connected wireless base station la is
capable of using the received UL receiving quality information in the
determination of UL reception destination and UL resource. As an example, the
connected wireless base station la is capable of determining, among the other
wireless base stations lb, lc capable of securing the UL wireless resource in the
amount requested in the UL schedule requesting information (this is obtained by
the other station wireless resource information), that having best receiving
quality indicated by the received UL receiving quality information as the UL
reception destination. Since S309 through S313 in FIG. 11 are similar to S108
through SI 12 in FIG. 3, the description is omitted.

[00176] As descriptions are given above based on FIG. 11, in the wireless
communication system of the third embodiment, the connected wireless base
station la selects the other wireless base station lb, which is the UL sending
destination, based on the UL receiving quality notified in advance from the other
wireless base stations lb, lc. In addition, therefore, the connected wireless
base station la sends the SRS resource information to the other wireless base
stations lb, lc in advance. Thus, the wireless communication system in the
third embodiment exhibits, in addition to an effect obtained by the wireless
communication system in the first embodiment, an effect of allowing selection of
the other wireless base stations lb, lc having good UL receiving quality as the
UL sending destination.
[00177] The functional configuration and the hardware configuration of the
respective device in the third embodiment follow those in the first embodiment,
so that the description is omitted.
[00178] [e] Fourth embodiment
[00179] The fourth embodiment is a modification that is applicable to as any
of the first embodiment through the third embodiment, and the connected
wireless base station la notifies the other wireless base stations lb, lc in
advance of a wireless-resource amount to be used for the UL sending of the
wireless terminal 2a.
[00180] In the following descriptions, descriptions are given to a
modification where the fourth embodiment is applied to the first embodiment.
Since this modification has many points in common with the first embodiment,
descriptions are given mainly to the points different from the first embodiment in
the following descriptions. As described before, although the fourth
embodiment may be modified by applying to the second embodimentor the third
embodiment, it may be applied similarly to that to the first embodiment and the
details are omitted.
[00181] Based on FIG. 12, descriptions are given to a process sequence of a
modification where the fourth embodiment is applied to the first embodiment.

[00182] Since S401 through S403 in FIG. 12 are similar to S101 through
S103 in FIG. 3, the description is omitted. In S404 in FIG. 12, the connected
wireless base station la sends wireless resource requesting information, which is
information to requesta UL wireless resource, to the other wireless base stations
lb, lc via the transmission network. At this time, the connected wireless base
station la in the present embodiment stores requested amount information of
the UL wireless resource included in the UL schedule requesting information
received in S402 in the wireless resource requesting information for sending.
[00183] In S405 in FIG. 12, as receiving wireless resource requesting
information respectively, the other wireless base stations lb, lc obtain unused
wireless resources. At this time, the other wireless base stations lb, lc in the
present embodiment obtain the unused wireless resources of the requested
amount based on the UL wireless resource amount information included in the
received wireless resource requesting information. In S406, the other wireless
base stations lb, lc send other station wireless resource information including
unused wireless resources information indicating the obtained unused wireless
resources to the connected wireless base station la via the transmission
network, respectively. The other station wireless resource information sent in
S406 satisfies the requested amount (of the UL wireless resource) included in the
wireless resource requesting information received in S404.
[00184] In S406, the connected wireless base station la receives other
station wireless resource information including the unused wireless resources
information respectively from the other wireless base stations lb, lc. Then, in
S407, the connected wireless base station la selects the UL wireless resource
that is used for UL data sending from the wireless terminal 2a based on the
received unused wireless resources information. Here, the connected wireless
base station la in the first embodiment arbitrarily selects unused wireless
resources of the requested wireless resource amount based on the received
unused wireless resources information in S107 in FIG. 3. In contrast, the
unused wireless resources information received by the connected wireless base

station la of the present embodiment indicates unused wireless resources of the
requested wireless resource amount. Therefore, the connected wireless base
station la in the present embodiment may select one item of the unused
wireless resources information received respectively from the other wireless base
stations lb, lc in S407. That is, in the connected wireless base station la of
the present embodiment, selection of the UL wireless resource based on the
unused wireless resources and selection of the other wireless base station lb to
be a sending destination of UL sending are equivalent. Here, it is assumed that
the connected wireless base station la selects the unused wireless resources of
the other wireless base station lb as the UL wireless resource.
[00185] In S408 in FIG. 12, the connected wireless base station la sends
the determined wireless resource information to the wireless terminal 2a (similar
to S108 in FIG. 3). In S409, the connected wireless base station la sends
response information indicating to be selected as the other wireless base station
lb to be a sending destination of UL sending to the other wireless base station
lb to be the sending destination of the UL sending. Here, the connected
wireless base station la in the present embodiment, different from the
connected wireless base station la in the first embodiment, does not have to
notify the other wireless base station lb of information indicating the selected
unused wireless resources. This is because the other wireless base station lb
recognizes the selected unused wireless resources. Since S410 through S412 in
FIG. 12 are same as SI 10 through SI 12 in FIG. 3, the description is omitted.
[00186] In the fourth embodiment, compared with the first embodiment,
although a size of wireless resource requesting information is slightly greater for
including the UL wireless resource amount information, the other station wireless
resource information (unused wireless resources information) may be same or
smaller. In addition, the connected wireless base station la may send, instead
of the determined wireless resource information, the response information.
Accordingly, according to the fourth embodiment, compared with the first

embodiment, an effect of suppressing the information amount sent and received
between the wireless base stations 1 is expected.
[00187] The functional configuration and the hardware configuration of the
respective device in the fourth embodiment follow those in the first embodiment,
so that the description is omitted.
[00188] [f] Fifth embodiment
[00189] The fifth embodiment is a modification that is applicable to any of
the first embodiment through the third embodiment, and the connected wireless
base station la notifies of, without obtaining other station wireless resource
information from the other wireless base stations lb, lc, a UL wireless resource
used for the UL sending from the wireless terminal 2a. In other words, the
connected wireless base station la notifies the other wireless base stations lb,
lc one-sidedly of the UL wireless resource used for the UL sending from the
wireless terminal 2a.
[00190] In the following descriptions, descriptions are given to a
modification where the fifth embodiment is applied to the first embodiment.
Since this modification has many points in common with the first embodiment,
descriptions are given mainly to the points different from the first embodiment in
the following descriptions. As described before, although the fifth embodiment
may be modified by applying to the second embodiment or the third
embodiment, it may be applied similarly to that to the first embodiment and the
details are omitted.
[00191] Based on FIG. 13, descriptions are given to a process sequence of a
modification where the fifth embodiment is applied to the first embodiment.
[00192] Since S501 through S503 in FIG. 13 is similar to S101 through S103
in FIG. 3, the description is omitted. When the UL reception destination is
determined as other than the local station in S503, the connected wireless base
station la further determines a UL wireless resource and a UL reception
destination used for the UL reception in S504. The connected wireless base

station la is capable of determining the UL wireless resource and the UL
reception destination used for the UL reception in an arbitrary method.
[00193] In S505, the connected wireless base station la sends the
determined UL wireless resource to the wireless terminal 2a (similar to S108 in
FIG. 3). Then, in S506, the connected wireless base station la sends wireless
resource requesting information, which is the information to request the
determined UL wireless resource, to the other wireless base station lb, which is
the determined UL sending destination, via the transmission network. Since
S507 through S509 in FIG. 13 are similar toSHO through S112 in FIG. 3, the
description is omitted.
[00194] In the fifth embodiment, compared with the first embodiment, the
other station wireless resource information (unused wireless resources
information) becomes not requested and the information sent from the
connected wireless base station la to the other wireless base station lb is also
reduced. Accordingly, according to the fifth embodiment, compared with the
first embodiment, an effect of suppressing the information amount sent and
received between the wireless base stations 1 is expected.
[00195] The functional configuration and the hardware configuration of the
respective device in the fifth embodiment follow those in the first embodiment,
so that the description is omitted.
[00196] [g] Sixth embodiment
[00197] The sixth embodiment is a modification that is applicable to as any
of the first embodiment through the third embodiment, and the other wireless
base stations lb, lc sense an event to be an opportunity, thereby sending other
station wireless resource information to the connected wireless base station la.
In other words, without sending wireless resource requesting information from
the connected wireless base station la to the other station wireless base stations
lb, lc, the other station wireless base stations lb, lc send other station wireless
resource information to the connected wireless base station la.

[00198] In the following descriptions, descriptions are given to a
modification where the sixth embodiment is applied to the first embodiment.
Since this modification has many points in common with the first embodiment,
descriptions are given mainly to the points different from the first embodiment in
the following descriptions. As described before, although the sixth embodiment
may be modified by applying to the second embodiment or the third
embodiment, it may be applied similarly to that to the first embodiment and the
details are omitted.
[00199] Based on FIG. 14, descriptions are given to a process sequence of a
modification where the sixth embodiment is applied to the first embodiment.
[00200] In S601 in FIG. 14, the other wireless base stations lb, lc sense a
predetermined event to be a trigger (opportunity) to send other station wireless
resource information. This event may be an arbitrary event and may be, as an
example, a lapse of predetermined time from the last sending of the other
station wireless resource information. As another example, it may be the UL
wireless used resource amount in the other wireless base stations lb, lc at a
predetermined value or less. Then, in S602 and S603, the other station wireless
base stations lb, lc confirm the used wireless resource and send the other
station wireless resource information (similar to S105 and S106 in FIG. 3).
[00201] In addition, in S604 through S606 in FIG. 14, UL data occurs in the
wireless terminal 2a, and the wireless terminal 2a sends UL schedule requesting
information and the connected wireless base station la determines whether or
not to set the UL reception destination as the local station (similar to S101
through S103 in FIG. 3). Then, when the UL reception destination is
determined as other than the local station in S606, the connected wireless base
station la determines, in S607, a UL wireless resource and a UL reception
destination based on the other station wireless resource information received in
S603. Since S607 through S612 in FIG. 14 are similar to S107 through SI 12 in
FIG. 3, the description is omitted. Although S601 through S603 in FIG. 14 are

carried out at a timing before S605, they do not have to be so and S601 through
S603 may be at any timing as long as before S607.
[00202] In the sixth embodiment, compared with the first embodiment, the
wireless resource requesting information becomes not requested. Accordingly,
according to the sixth embodiment, compared with the first embodiment, an
effect of suppressing information amount sent and received between the wireless
base stations 1 is expected.
[00203] The functional configuration and the hardware configuration of the
respective device in the sixth embodiment follow those in the first embodiment,
so that the description is omitted.
[00204] [h] Seventh embodiment
[00205] In the seventh embodiment, the wireless terminal 2a generates and
sends a DM-RS, which is one of the UL reference signals, in accordance with the
other wireless base station lb, which is a UL sending destination. It is possible
to combine the seventh embodiment with the first embodiment or the second
embodiment, and there are many points in common with them. In the following
descriptions, descriptions are given mainly to the points in the seventh
embodiment different from the first embodiment in the following descriptions.
[00206] In a conventional LTE system and the wireless communication
system of the first embodiment, when sending a UL wireless frame, the wireless
terminal 2a generates a DM-RS, which is one of the UL reference signal, and
maps it in a UL wireless frame for sending. The connected wireless base station
la that has received the UL wireless frame demodulates the UL control signal
and the data signal using channel characteristics to estimate the channel
characteristics based on the DM-RS.
[00207] Here, the DM-RS is information (pattern) different for each wireless
base station 1. Specifically, the DM-RS is generated based on a base station
identifier. In a regular LTE system, the wireless terminal 2a generates a DM-RS
for the connected wireless base station la using the identifier of the connected
wireless base station la and sends it in a UL wireless frame. Then, the

connected wireless base station la carries out channel estimation by analyzing
the DM-RS in the received UL wireless frame using the identifier of the
connected wireless base station la. Thus, the connected wireless base station
la is capable of appropriately receiving the DM-RS and capable of estimating the
channel characteristics with high precision, so that decoding errorsare
suppressed.
[00208] However, a problem occurs in the first embodiment and the second
embodiment when the UL sending destination of the wireless terminal 2a
becomes the other wireless base station lb. Even when the wireless terminal
2a sends the DM-RS towards the connected wireless base station la, the other
wireless base station lb receives the DM-RS and utilizes it for demodulation.
Since the DM-RS towards the other wireless base station lb is generally different
from the DM-RS towards the connected wireless base station la, the other
wireless base station lb is not capable of appropriately estimating the channel
characteristics based on the DM-RS. In this case, it turns out to increase
decoding errors and thus not preferred.
[00209] In order to solve this problem, in the seventh embodiment, when
the UL sending destination of the subordinate wireless terminal 2a is the other
wireless base station lb, the connected wireless base station la stores an
identifier of the other wireless base station lb in the DL control information
(DCI) for sending. Then, the wireless terminal 2a having received the DL
wireless frame, when sending the UL wireless frame, generates the DM-RS using
the identifier of the other wireless base station lb and maps the DM-RS in the UL
wireless frame for sending.
[00210] FIG. 15 illustrates a DCI format in the seventh embodiment. FIG.
15 (A) is a DCI format of a modification where the seventh embodiment is
applied to the first embodiment. FIG. 15 (B) is a DCI format of a modification
where the seventh embodiment is applied to the second embodiment. The DCI
formats in FIG. 15 both have a region to store a UL sending destination
identifier, which is an identifier of the other wireless base station lb.

[00211] According to the seventh embodiment, the wireless terminal 2a is
capable of generating and sending the DM-RS towards the other wireless base
station lb, so that an effect of suppressing decoding errors in the other wireless
base station lb is obtained.
[00212] The functional configuration and the hardware configuration of the
respective device in the seventh embodiment follow those in the first
embodiment, so that the description is omitted.
[00213] [i] Eighth embodiment
[00214] The eighth embodiment is also to solve the problem same as the
seventh embodiment, and it is possible to combine with the first embodiment or
the second embodiment. Since the eighth embodiment has many points in
common with the seventh embodiment, descriptions are given mainly to the
points in the eighth embodiment different from the seventh embodiment in the
following descriptions.
[00215] In the eighth embodiment, it does not have to store an identifier of
the other wireless base station lb in the DCI as in the seventh embodiment.
Instead, in the eighth embodiment, the other wireless base station lb analyzes
the DM-RS in the received UL wireless frame using the identifier of the
connected wireless base station la (not the identifier of itself) and carries out
channel estimation. The other wireless base station lb is capable of learning
the identifier of the connected wireless base station la in a message sent and
received with the connected wireless base station la.
[00216] According to the eighth embodiment, the other wireless base
station lb is capable of appropriately receiving the DM-RS towards the connected
wireless base station la and capable of estimating the channel characteristics
with high precision, so that an effect of suppressing decoding errors is obtained.
Comparing the seventh embodiment with the eighth embodiment, the former has
to use a function compatible with both the wireless base stations 1 and the
wireless terminals 2, while the latter has to use a function compatible only with

the wireless base stations 1, so that the latter is considered to be easier for
introduction.
[00217] The functional configuration and the hardware configuration of the
respective device in the eighth embodiment follow those in the first embodiment,
so that the description is omitted.
[00218] [j] Ninth embodiment
[00219] The ninth embodiment is also to solve the problem same as the
seventh embodiment and the eighth embodiment, and it is possible to combine
with the first embodiment or the second embodiment. The ninth embodiment is
equivalent to an embodiment in which the seventh embodiment and the eighth
embodiment are combined.
[00220] When an identifier of the other wireless base station lb is stored in
the DCI in the received DL wireless frame, the wireless terminal 2a in the present
embodiment generates the DM-RS using the identifier of the other wireless base
station lb. At this time, the other wireless base station lb analyzes the DM-RS
in the UL wireless frame received as regularly using the identifier of itself and
carries out channel estimation.
[00221] In contrast, when the identifier of the other wireless base station
lb is not stored in the DCI, the wireless terminal 2a generates the DM-RS using
an identifier of the connected wireless base station la. At this time, the other
wireless base station lb analyzes the DM-RS in the received UL wireless frame
using the identifier of the connected wireless terminal 2a and carries out channel
estimation.
[00222] The other wireless base station lb is regularly not capable of
learning whether or not an identifier of the other wireless base station lb is
stored in the DCI. Therefore, the other wireless base station lb has to be
notified of whether or not the identifier of the other wireless base station lb is
stored in the DCI from the connected wireless base station la in advance.

[00223] By the ninth embodiment as well, similar to the seventh and eighth
embodiments, an effect of suppressing decoding errors in the other wireless base
station lb is obtained.
[00224] The functional configuration and the hardware configuration of the
respective device in the ninth embodiment follow those in the first embodiment,
so that the description is omitted.
[00225] [k] Other embodiments
[00226] In the first through ninth embodiments described above, when the
wireless terminal 2a is UL sent to the other wireless base station 2b, the
connected wireless base station la carries out determination of the other
wireless base station 2b to be the destination (determined wireless base station)
and the UL wireless resource to be used (determined wireless resource).
However, the subject of such determination is not limited to the connected
wireless base station la.
[00227] For example, an upper station (upper device) connected to the core
network and the like may also determine the determined wireless base station
and the determined wireless resource. In addition, the other wireless base
station lb different from the connected wireless base station la may also
determine the determined wireless base station and the determined wireless
resource. Further, the wireless terminal 2a may also determine the determined
wireless base station and the determined wireless resource.
[00228] Further, an upper station (upper device), the other wireless base
station lb, the wireless terminal 2a, and the like may also receive other station
wireless resource information from the other wireless base stations 2b, 2c in a
procedure similar to that carried out by the connected wireless base station la in
the first through ninth embodiments described above. Then, the upper station
(upper device), the other wireless base station 2b, wireless terminal 2a, and the
like may also determine the determined wireless base station and the determined
wireless resource based on the received other station wireless resource
information.

[00229] 1 wireless base station
[00230] 2 wireless terminal

[Claim 1]
A wireless communication system comprising:
a wireless base station; and
a wireless terminal that carries out wireless communication with the
wireless base station; wherein
the wireless base station includes
a receiving unit that receives first information related to a first uplink
resource not used by another wireless terminal that carries out wireless
communication with another wireless base station, and
a downlink wireless sending unit that sends second information
indicating a second uplink resource selected from the first uplink resource for
sending to the other wireless base station to the wireless terminal based on the
first information.
[Claim 2]
The wireless communication system according to claim 1, wherein
the wireless base station further includes a sending unit that sends the
second information to the other wireless base station.
[Claim 3]
The wireless communication system according to claim 1 or 2, wherein
the wireless terminal includes an uplink wireless sending unit that sends
a wireless signal to the other wireless base station using the second uplink
resource indicated by the second information.
[Claim 4]
The wireless communication system according to any one of claims 1
through 3, wherein

the second information indicates the second uplink resource in
association with a downlink resource for sending from the wireless base station
to the wireless terminal.
[Claim 5]
The wireless communication system according to any one of claims 1
through 4, wherein
the second information indicates the second uplink resource in an offset
from a downlink resource for sending from the wireless base station to the
wireless terminal.
[Claim 6]
A wireless base station comprising:
a receiving unit that receives first information related to a first uplink
resource not used by another wireless terminal that carries out communication
with another wireless base station; and
a downlink wireless sending unit that sends second information
indicating a second uplink resource selected from the first uplink resource for
sending to the other wireless base station to a wireless terminal based on the
first information.
[Claim 7]
The wireless base station according to claim 6, wherein
the wireless base station further includes a sending unit that sends the
second information to the other wireless base station.
[Claim 8]
The wireless base station according to claim 6 or 7, wherein

the second information specifies the second uplink resource in
association with a downlink resource for sending from the wireless base station
to the wireless terminal.
[Claim 9]
The wireless base station according to any one of claims 6 through 8,
wherein
the second information specifies the second uplink resource in an offset
from a downlink resource for sending from the wireless base station to the
wireless terminal.
[Claim 10]
A wireless base station, connected by a wireless terminal, comprising:
a sending unit that sends first information related to a first uplink
resource not used by the wireless terminal; and
a wireless receiving unit that receives a wireless signal from another
wireless terminal based on a second uplink resource selected by another wireless
base station from the first uplink resource for sending to the wireless base
station based on the first information.
[Claim 11]
The wireless base station according to claim 10, wherein
the second information indicates the second uplink resource in
association with a downlink resource for sending from the wireless base station
to the wireless terminal.
[Claim 12]
The wireless base station according to claim 10 or 11, wherein

the second information indicates the second uplink resource in an offset
from a downlink resource for sending from the wireless base station to the
wireless terminal.
[Claim 13]
A wireless terminal carrying out communication with a wireless base
station, comprising:
a wireless receiving unit that receives second information indicating a
second uplink resource selected from the first uplink resource based on first
information, from the wireless base station that has received first information
related to a first uplink resource not used by another wireless terminal carrying
out communication with the other wireless base station; and
a wireless sending unit that sends a wireless signal to the other wireless
base station based on the second uplink resource.
[Claim 14]
The wireless terminal according to claim 13, wherein
the second information indicates the second uplink resource in
association with a downlink resource for sending from the wireless base station
to the wireless terminal.
[Claim 15]
The wireless terminal according to claim 13 or 14, wherein
the second information indicates the second uplink resource in an offset
from a downlink resource for sending from the wireless base station to the
wireless terminal.
[Claim 16]
A wireless communication method in a wireless communication system
provided with a wireless base station and a wireless terminal that carries out

wireless communication with the wireless base station, the wireless
communication method comprising:
receiving first information, by the wireless base station, that is related to
a first uplink resource not used by another wireless terminal carrying out wireless
communication with another wireless base station; and
sending second information, by the wireless base station, that indicates a
second uplink resource selected from the first uplink resource for sending to the
other wireless base station to the wireless terminal based on the first
information.
[Claim 17]
The wireless communication method according to claim 16, wherein
the wireless base station sends the second information to the other
wireless base station.
[Claim 18]
The wireless communication method according to claim 16 or 17,
wherein
the wireless terminal sends a wireless signal to the other wireless base
station using the second uplink resource indicated by the second information.
[Claim 19]
The wireless communication method according to any one of claims 16
through 18, wherein
the second information indicates the second uplink resource in
association with a downlink resource for sending from the wireless base station
to the wireless terminal.
[Claim 20]

The wireless communication method according to any one of claims 16
through 19, wherein
the second information indicates the second uplink resource in an offset
from a downlink resource for sending from the wireless base station to the
wireless terminal.