DESCRIPTION
Title of Invention
COMMUNICATION DURATION CONFIGURING METHOD, RELAY STATION,
MOBILE STATION AND MOBILE COMMUNICATION SYSTEM
Technical Field
The embodiments discussed herein are related to a
relay technology of radio communication between a base
station and a mobile station.
Background Art
In a cellular mobile communication system, an
evolution from a UMTS (universal mobile telecommunication
system) to an LTE (long term evolution) has been devised.
In the LTE, an OFDM (orthogonal frequency division
multiplexing) and an SC-FDMA (single carrier-frequency
division multiple access) are adopted respectively as
downlink and uplink radio access technology, thereby
enabling a high-speed radio packet communication to be
performed at 100Mb/s or higher for a downlink peak
transmission rate and 50Mb/s or higher for an uplink peak
transmission rate. In the 3GPP (3rd Generation Partnership
Project) as an international standardization organization,
a study of a mobile communication system LTE-A (LTE-
Advanced) based on the LTE has been started to realize a

further high-speed communication. In the LTE-A, the
downlink peak transmission rate of 1Gb/s and the uplink
peak transmission rate of 500Mb/s are aimed at, and various
new techniques are studied on a radio access system, a
network architecture, etc. (non-patent literatures 1 to 3).
Note that, since the LTE-A is based on the LTE, it is
devised to maintain backward compatibility.
As one of the methods for establishing a high-
speed data communication, the method of deploying a relay
station (relay node (RN)) as illustrated in FIG. 1 has been
studied to support the communication between a base station
and a mobile station (non-patent literature 2). The relay
station relays the communication between a base station
(Doner eNB or eNB) and a mobile station (user equipment
(UE)), and is provided to support a high-speed data
communication. As illustrated in FIG. 2, the link between
the mobile station UE and the relay station RN is referred
to as a Uu, and the link between the base station (eNB) and
the relay station (RN) is referred to as a Un. In the
following explanation, the Uu may be referred to as an
access link, and the Un may be referred to as a backhaul
link.
Various schemes can be implemented to embody a
relay station, but for example, a repeater scheme, a decode
and forward scheme, an L2 scheme, and an L3 scheme have
been studied. The relay station in the repeater scheme has
only the function of amplifying a radio signal (data signal

and noise). The relay station in the decode and forward
scheme has the function of amplifying only a data signal in
the radio signal. The relay station in the L2 scheme has
the function of the L2 such as a MAC layer etc. The relay
station in the L3 scheme has the function of the L3 such as
an RRC layer etc., and functions like a base station. The
relay station in the L3 scheme is referred to as a Typel RN
in the LTE-A.
A method of evolving a relay station in to a cell
is also studied. For example, a method of evolving a relay
station to be provided at a cell edge to increase the
throughput of the cell edge, a method of evolving a relay
station to be provided in a range where radio waves do not
reach from the base station locally in a cell (dead spot) ,
etc. are studied.
When data is transmitted between the base station
and the mobile station through the relay station (Typel RN)
of the L3 scheme, it is preferable that no self-
interference is generated in the relay station in inband
relaying in which the same frequency band is shared between
the base station and the relay station, and between the
relay station . and the mobile station. The self-
interference (or also called "loop interference") refers to
interference occurring when the relay station receives DL
data from the base station to the relay station and
simultaneously transmits downlink data to the mobile
station, and the transmission data appears in a receiver of

the relay station, thereby generating interference with the
data from the base station. Likewise with the uplink data,
there can occur the self-inter f erence. When the self-
. interference occurs, the relay station cannot correctly
receive data.
To overcome the problem of the self-interference,
the following policies are studied for LTE-A (non-patent
literature 2).
(A) Downlink: The relay station does not transmit
data to the mobile station in the DL backhaul as a subframe
for receiving data from an upper base station.
(B) Uplink; The relay station does not receive
data from the mobile station in the UL backhaul as a
subframe for transmitting data to an upper base station.
Based on the policy (A) above, as illustrated in
FIG. 3, when the downlink backhaul is set between the relay
station and the base station, the subframe between the
relay station and the mobile station is set as an MBS FN
(multicast/broadcast over single frequency network)
subframe because, in the MBSFN subframe, the mobile station
for the LTE does not receive unicast data. Therefore,
since the mobile station UE does not receive a part of a
reference signal, it is preferable because it is not
necessary to make an unnecessary measurement of the
reference signal in the mobile station. That is to say,
the relay station can transmit a PDCCH (physical downlink
control channel), a PHICH (physical hybrid ARQ indicator

channel), a PCFICH (physical control format indicator
channel) while it cannot transmit a PDSCH. To receive the
control signal, a reference signal is arranged in the first
half (CTRL section illustrated in FIG. 3) of the MBSFN
subframe, but it is not arranged in the last half of the
MBSFN subframe.
Based on the policy (B) above, control is
performed in the relay ' station not to grant the mobile
station permission to transmit uplink data before 4
subframes (4ms) in the UL backhaul because if the mobile
station is granted the permission to transmit uplink data
before 4ms in the uplink backhaul, the mobile station
transmits data to the relay station in the uplink backhaul,
which is to be avoided.
Furthermore, in the relay station, control is
performed not to transmit downlink data to the mobile
station before 4 subframes (4ms) in the uplink backhaul for
the following reason. That is, in the HARQ (hybrid
automatic repeat request) of the LTE, it is regulated that
a receiving station is to return an ACK/NACK signal in 4ms
(4 subframes) after a transmitting station transmits data.
Therefore, if downlink data is transmitted to the mobile
station in 4ms in the uplink backhaul, the mobile station
transmits the ACK/NACK signal to the relay station in the
uplink backhaul, which is to be avoided.
In the uplink backhaul, a PUCCH (physical uplink
control channel) and a PUSCH (physical uplink shared

channel) as control signals to the relay station can be
transmitted, but the PUCCH and the PUSCH as control signals
from the mobile station cannot be transmitted.
Citation List
Non-Patent Literature
NPTL1: 3GPP TR 36. 913 V8. 0. 1 (2009-03) , 3rd
Generation Partnership Project; Technical Specification
Group Radio Access Network; Requirements for further
advancements for Evolved Universal Terrestrial Radio Access
(E-UTRA) (LTE-Advanced) (Release 8)
NPTL2: 3GPP TR 36. 912 V9. 0. 0 (2009-09), 3rd
Generation Partnership Project; Technical Specification
group Radio Access Network; Feasibility study for Further
Advancements for E-UTRA (LTE-Advanced) (Release 9)
NPTL3: 3GPP TR 36. 133 V0. 1. 1 (2009-11) , 3rd
Generation Partnership Project; Technical Specification
Group Radio Access Network; Evolved Universal Terrestrial
Radio Access (E-UTRA); Requirements for support of radio
resource management (Release 9)
Summary of Invention
Technical Problem
As illustrated in non-patent literature 2, a
backhaul is discussed with regard to the LTE-A. There is
made a study on whether to establish downlink and uplink
backhauls in which subframe of a radio Frame in the LTE-A.

Suppose that a backhaul is always fixedly configured in a
position of the same" subframe in a radio Frame. When
considering a relationship between a HARQ (Hybrid Automatic
Repeat reQuest) and performance timing, there arise the
following problems. These problems will be described in
detail below. Suppose that in the following description,
as illustrated in FIG. 4, a radio frame having a duration
of 10 ms is composed of ten subframes #0 to #9 each having
a duration of 1 ms as a TTI (Transmission Time Interval).
An example in the case where a backhaul is always
configured in a position of the same subframe in a radio
Frame will be described with reference to FIG. 5. In the
continuing Frames (Frame_0, Frame_l, Frame_2, Frame_3, ...) ,
FIG. 5 illustrates setting of 1 ms unit or timing of
operations of (a) a downlink backhaul DL_BH, (b) a
downstream access link DL_AL, (c) an uplink backhaul UL_BH,
(d) an upstream access link UL_AL, and (e) HARQ processes
(process numbers PID1, ..., PID8) of access link. In FIG. 5,
a downward arrow indicates transmission of a downlink
signal, and an upward arrow indicates transmission of an
uplink signal.
In (a) to (d) of FIG. 5, black-filled portions
mean that backhauls or access links are incapable of being
configured. In (a) of FIG. 5, for example, since
downstream access links are used in the subframes #0, #4,
#5, and #9 for transmission of control data, the downlink
backhauls are incapable of being configured in these

subframes. therefore, in this example, downlink backhauls
are configured in the subframes #1 in all of the continuing
Frames. In the specifications of the LTE, since an
ACK/NACK signal is sent back after 4 ms of data
transmission, the relay station RN sends back the ACK/NACK
signal to the subframe #5 with respect to the data
transmission through the base station eNB in the subframe
#1. As a result, in (c) of FIG. 5, the uplink backhauls
are configured in the subframes #5. In (a) and (c) of FIG.
5, durations of the downlink or uplink backhauls are
highlighted by solid thick frame lines.
When the downlink backhauls are configured in the
subframes #1 and the uplink backhauls are configured in the
subframes #5, access links are incapable of being
configured in the same subframes. Therefore,as
illustrated in (b) and (d) of FIG. 5, portions of the
subframes #1 are displayed (incapable of being configured)
to be black-filled in the downstream access links. On the
other hand, portions of the subframes #5 are displayed to
be black-filled (incapable of being configured) in the
upstream access links.
There are two problems in the case where a
backhaul is always configured in a position of the same
subframe in one Frame as illustrated in FIG. 5.
First, a first problem is that backward
compatibility with the LTE is lost. As described above, in
the specifications of the LTE, an ACK/NACK signal is sent

back after 4 ms of the data transmission. However, when
the backhaul is configured as illustrated in FIG. 5, the
ACK/NACK signal is to be sent back after 6 ms, and
therefore the specifications of the LTE are not satisfied.
In the example of FIG. 5, the ACK/NACK signal from the base
station eNE toward the data transmission through the uplink
backhaul (subframe #5) corresponds to the downlink backhaul
(subframe #1) of the next Frame. However, when the
backward compatibility with the LTE need not be maintained
with regard to the reply timing of the HARQ, the above
matter does not become a big problem.
Next, a second problem is as follows. That is, in
the configuration of the backhaul illustrated in FIG. 5, a
HARQ process in which the HARQ of an access link is
incapable of being performed and duration of the HARQ
process are scattered. Therefore, effective scheduling of
the access link becomes difficult in the relay station RN.
In the example illustrated in FIG. 5, a part (four
portions; illustrated by thick lines) of the HARQ processes
of the process numbers PID2, PID4, PID6, and PID8 are
incapable of being used. Specifically, in the HARQ
processes of the process numbers PID2, PID4, PID6, and PID8,
timing points of the uplink data transmission are matched
with the uplink backhauls of the Frame_2, Frame_3, Frame_0,
and Frame_l, respectively, and therefore the access links
are incapable of being used. Accordingly, in the case of
performing new data transmission, particular duration

scattered as illustrated in FIG. 5 of the HARQ process in
which the HARQ is incapable of being performed are avoided
and scheduling is to be configured. As a result, there are
problems that complexity of the scheduling is increased and
the efficiency of the access link is reduced.
Based on the above-described viewpoint, it is an
object in one aspect of the embodiments to provide a
communication duration configuring method, a relay station
RN, a mobile station UE, and a mobile communication system
in such a manner that a reduction in efficiency of the
access link is suppressed at the time of configuring a
communication duration between a base station eNB and a
relay station RN in the mobile communication system
including the relay station RN which relays radio
communication between the base station eNB and the mobile
station UE.
Solution to Problem
A first viewpoint is a communication duration
configuring method for use in a mobile communication system
including a relay station which relays radio communication
between a base station and a mobile station. This
communication duration configuring method includes:
(A) configuring at least one of a downlink
communication duration in which the replay station receives
a transmission signal from the base station while limiting
transmission of a signal from the relay station to the

mobile station and an uplink communication duration in
which the raiay station transmits a transmission signal to
the base station while limiting transmission of a signal
from the mobile station to the relay station;
(B) providing a plurality of communication
processes in which first communication processing including
data transmission and an acknowledgment after a
predetermined first time period from the data transmission
is managed on an access link between the mobile station and
the relay station;
(C) configuring the uplink communication duration
at timing according to. the timing of uplink data
transmission of a particular first communication process
among the plurality of communication processes; and
(D) configuring a downlink communication duration
before the predetermined first time period of each of the
configured uplink communication duration.
A second viewpoint is a relay station to be
movable and to relay radio communication between a base
station and a mobile station. This relay station includes:
(E) a first transmission and reception unit to
transmit andreceive a signal between the relay station and
the base station;
(F) a second transmission and reception unit to
transmit and receive a signal between the relay station and
the mobile station;
(G) a control unit to configure at least one of a

downlink communication duration in which a first
transmission and reception unit receives a transmission
signal from the base station while a second transmission
and reception unit limits transmission of a signal to the
mobile station and an uplink communication duration in
which the fi rst transmission and reception unit transmits a
transmission signal to the base station while the mobile
station limits transmission of a signal to the relay
station; and
(H) a first communication management unit to
manage a plurality of communication processes in which
first communication processing including data transmission
and an acknowledgment after a predetermined first time
period from the data transmission is provided on an access
link between the mobile station and the relay station,
wherein the control unit configures the
communication duration so that, among the plurality of
communication processes, a communication process in which
the first communication processing is incapable of being
performed is integrated into a particular communication
process.
A third viewpoint is a mobile station to perform
radio communication with a base station through a relay
station. This mobile station includes:
(I) a transmission and reception unit to transmit
and receive a radio signal to and from the relay station;
and

(J) a second communication management unit to
manage communication timing between the mobile station and
the relay station based on at least one of a downlink
communication duration in which the relay station receives
a transmission signal from the base station while limiting
transmission of a signal from the relay station to the
mobile station and an uplink communication duration in
which the relay station transmits a transmission signal to
the base station while limiting transmission of a signal
from the mobile station to the relay station,
wherein the communication duration is configured
in such a manner that, among the plurality of communication
processes, a communication process in which the first
communication processing is incapable ofbeing performed is
integrated into a particular communication process.
A fourth viewpoint is a mobile communication
system including a base station; a mobile station; and a
relay station which relays radio communication between the
base station and the mobile station.
Advantageous Effects of Invention
The proposed communication duration configuring
method, relay station RN, mobile station UE, and mobile
communication system permit a mobile communication system
including the relay station RN which relays radio
communication between the base station eNB and the mobile
station UE to suppress a reduction in efficiency of an

access link at the time of configuring a communication
duration between the base station eNB and the relay station
RN.
Brief Description of Drawings
[FIG. 1] FIG. 1 is a configuration diagram
illustrating a mobile communication system including a
relay station RN which supports communication between a
base station eNB and a mobile station UE.
[FIG. 2] FIG. 2 illustrates a link configuration
among a base station eNB, a relay station RN, and a mobile
station UE.
[FIG. 3] FIG. 3 illustrates a configuration
guideline of a known backhaul.'
[FIG. 4] FIG. 4 illustrates a configuration of one
Frame.
[FIG. 5] FIG. 5 illustrates a problem in the case
of configuring a backhaul in a position of the same
subframe in a radio Frame at all times.
[FIG. 6] FIG. 6 illustrates a configuration
condition of a backhaul configuring method according to a
first embodiment.
[FIG. 7-1] FIG. 7-1 illustrates one example of a
backhaul configuring method according to a first embodiment.
[FIG. 7-2] FIG. 7-2 illustrates one example of a
backhaul configuring method according to a first embodiment.
[FIG. 7-3] FIG.7-3 illustrates one example of a

backhaul configuring method according to a first embodiment.
[FIG: 7-4] FIG. 7-4 illustrates one example of a
backhaul configuring method according to a first embodiment.
[FIG. 7-5] FIG. 7-5 illustrates one example of a
backhaul configuring method according to a first embodiment.
[FIG. 7-6] FIG. 7-6 illustrates one example of a
backhaul configuring method according to a first embodiment.
[FIG. 7-7] FIG. 7-7 illustrates one example of a
backhaul configuring method according to a first embodiment.
[FIG. 7-8] FIG. 7-8 illustrates one example of a
backhaul configuring method according to a first embodiment.
[FIG. 8-1] FIG. 8-1 illustrates one example of a
backhaul configuring method according to a second
embodiment.
[FIG. 8-2] FIG. 8-2 illustrates one example of a
backhaul configuring method according to a second
embodiment.
[FIG. 8-3] FIG. 8-3 illustrates one example of a
backhaul configuring method according to a second
embodiment.
[FIG. 8-4] FIG. 8-4 illustrates one example of a
backhaul configuring method according to a second
embodiment.
[FIG. 8-5] FIG. 8-5 illustrates one example of a
backhaul configuring method according to a second
embodiment.
[FIG. 8-6] FIG. 8-6 illustrates one example of a

backhaul configuring method according to a second
embodiment.
[FIG. 8-7] FIG. 8-7 illustrates one example of a
backhaul configuring method according to a second
embodiment.
[FIG. 8-8] FIG. 8-8 illustrates one example of a
backhaul configuring method according to a second
embodiment.
[FIG. 9] FIG. 9 tabulates backhauls configured by
a backhaul configuring method exemplified in FIGS. 8-1 to
8-8.
[FIG. 10-1] FIG. 10-1 illustrates one example of a
backhaul configuring method according to a third embodiment.
[FIG. 10-2] FIG. 10-2 illustrates one example of a
backhaul configuring method according to a third embodiment.
[FIG. 10-3] FIG. 10-3 illustrates one example of a
backhaul configuring method according to a third embodiment.
[FIG. 10-4] FIG. 10-4 illustrates one example of a
backhaul configuring method according to a third embodiment.
[FIG. 10-5] FIG. 10-5 illustrates one example of a
backhaul configuring method according to a third embodiment.
[FIG. 10-6] FIG. 10-6 illustrates one example of a
backhaul configuring method according to a third embodiment.
[FIG. 10-7] FIG. 10-7 illustrates one example of a
backhaul configuring method according to a third embodiment.
[FIG. 10-8] FIG. 10-8 illustrates one example of a
backhaul configuring method according to a third embodiment.

[FIG. 11] FIG. 11 tabulates backhauls configured
by a backhaul configuring method exemplified in FIGS. 10-1
to 10-8.
[FIG, 12] FIG. 12 illustrates one example of
durations of a Measurement gap configured in a fourth
embodiment.
[FIG. 13] FIG. 13 is a block diagram illustrating
a schematic configuration of a relay station RN according
to a fifth embodiment.
[FIG. 14] FIG. 14 is a block diagram illustrating
a schematic configuration of a mobile station UE according
to a fifth embodiment.
[FIG. 15] FIG. 15 is a flowchart illustrating one
example of operations of a relay station RN according to a
fifth embodiment.
[FIG. 16] FIG. 16 is a flowchart illustrating one
example of operations of a relay station RN according to a
fifth embodiment.
[FIG. 17] FIG. 17 is a flowchart illustrating one
example of operations of a mobile station UE according to a
fifth embodiment.
[FIG. 1.8] FIG. 18 is a flowchart illustrating one
example of operations of a mobile station UE according to a
fifth embodiment.
Description of Embodiments
A plurality of embodiments will be described below.

In the following description, a Donor eNB, a Relay Node,
and User Equipment are appropriately abbreviated as a base
station eNB," an RN, and a mobile station UE, respectively.
The base station eNB according to the present embodiment is
a Donor eNB which supports a backhaul between its own
station and the relay station RN. Further, a HARQ is
appropriately referred to as one indicating processing
(first communication processing) including data
transmission and an acknowledgment after a predetermined
time from the data transmission.
In the following description, a backhaul duration
represents one duration unit or a plurality of duration
units among a plurality of duration units configured in a
TTI (Transmission Time Interval) unit in a single radio
Frame. In the present embodiment, the TTI is configured as
time of a subframe (1 ms) unit. "Configuring a backhaul"
means that a backhaul is configured or identified as a
subframe in the radio frame. Note that also in the case
where the TTI is not time of a subframe unit, the present
embodiment is applicable.
(1) First Embodiment
A backhaul configuring method according to a first
embodiment will be described below.
The backhaul configuring method according to the
present embodiment is a method of a case where backward
compatibility with the LTE is maintained with regard to
reply timing of the HARQ. Specifically, with regard to the

reply timing of the HARQ, an ACK/NACK signal (A/N;
acknowledgment) is here assumed to be sent back after 4 ms
of the data transmission. In this backhaul configuring
method, it is intended that complexity of scheduling is
reduced and efficiency of an access link is improved in
such a manner that the number of HARQ processes ,
(communication processes) incapable of being partly used is
reduced as much as possible.
First, a configuration condition at the time of
the backhaul configuring method according to the present
embodiment will be described with reference to FIG. 6. A
format of FIG. 6 is the same"as that of the above-described
FIG. 5.
Specifically, in FIG. 6, configurations of 1 ms
unit or timing points of operations in each of (a) a
downlink backhaul DL_BH, (b) a downstream access link DL_AL,
(c) an uplink backhaul UL_BH, (d) an upstream access link
UL_AL, and (e) a HARQ process (process numbers PID1, ...,
PID8) as a communication process of an access link are
illustrated in continuing Frames (Frame_0, Frame_l, Frame_2,
Frame_3, ...) . In FIG. 6, a downward arrow indicates
transmission of. a downlink signal, and an upward arrow
indicates transmission of an uplink signal, respectively.
In (a) to (d) of FIG. 6, black-filled portions
each mean that a backhaul link or access link is incapable
of being configured. On the other hand, in (a) to (d) of
FIG. 6, subframes surrounded by solid thick frame lines

each mean that a backhaul or access link is secured in the
subframe.
Specifically, in the LTE, since the subframes #0,
#4, #5, and #9 are used for a Primary Synchronization
Channel, Paging, Secondary Synchronization Channel, and
Paging in the downstream access link, respectively, the
downlink backhaul is incapable of being configured in these
subframes. Therefore, in the downlink backhaul DL_BH, the
subframes #0, #4, #5, and #9 are black-filled in respective
Frames, and in the downstream access link DL AL, the
subframes #0, #4, #5, and #9 are surrounded by solid thick
frame lines in respective Frames. Further, after 4 ms of
the transmission from the relay station RN on the
downstream access links of the subframes #0, #4, #5, and #9,
the upstream access link for a reply of the ACK/NACK signal
(A/N) is used. Therefore, in the upstream access link
UL_AL, the subframes #4, #8, #9, and #3 are surrounded by
solid thick frame lines in respective Frames. In the
uplink backhaul UL_BH, the subframes #4, #8, #9, and #3 are
black-filled _in respective Frames.
Based on the configuration condition at the time
of the backhaul, configuring method illustrated in FIG. 6,
the backhaul configuring method according to the present
embodiment will be specifically described with reference to
FIGS. 7-1 to..7-8. Format's of FIGS. 7-1 to 7-8 are the same
as that of FIG. 6. FIGS. 7-1 to 7-8 illustrate a case
where the HARQ processes of the process numbers PID1 to

PID8 are configured as a HARQ process in which a HARQ is
incapable of being at least partly used. In FIGS. 7-1 to
7-8, timing at which the HARQ is incapable of being
performed is illustrated by thick lines.
FIG. 7-1 illustrates the backhaul configuring
method in the case where only the HARQ process of the
process number PID1 is configured as a HARQ process in
which a HARQ is incapable of being partly performed among
the HARQ processes ""'of the process numbers PID1 to PID8.
That is, the HARQ process in which the HARQ is incapable of
being partly performed is limited to the HARQ process of .
the process number PIDl.
In FIG. 7-1, the downlink backhauls of three times
are secured among the continuing four Frames. Specifically,
in FIG. 7-1, the downlink backhauls are configured in a
subframe #2 of the Frame_l, the subframe #8 of the Frame_2,
and a subframe #6 of the Frame_3. Also, in the same
positions as in the above also in Frames continuous with
the Frame_0 to Frame_3, ..the downlink backhauls are
configured. After 4 ms of the data transmission from the
base station eNB on the thus configured downlink backhaul,
the ACK/NACK signal is sent back from the relay station RN.
Therefore, the uplink backhauls are configured in the
subframe #6 of the Frame_l, the subframe #2 of the Frame_3,
and the subframe #0 of the Frame_0.
On this uplink backhaul, an upstream access link
is incapable of being used. As illustrated in (e) of FIG.

7-1, all the HARQs (performance timing of thick lines)
incapable of being performed belong to the same HARQ
process (namely, the process number PID1).
FIG. 7-2 illustrates the backhaul configuring
method in the case where only the HARQ process of the
process number PID2 is configured as a HARQ process in
which a HARQ is incapable of being partly performed among
the HARQ processes of the process numbers PID1 to PID8.
That is, a HARQ process in which the HARQ is incapable of
being partly performed is limited to the HARQ process of
the process number PID2.
In FIG. 7-2, the downlink backhauls of three times
are secured among the four continuing Frames. Specifically,
in FIG. 7-2, the downlink backhauls are configured in the
subframe #3 of the Frame_1, a subframe #1 of the Frame_2,
and a subframe #7 of the Frame_3. Also, in the same
positions as in the above also in Frames continuous with
the Frame_0 to Frame_3, the downlink backhauls are
configured. After 4 ms of the data transmission from the
base station eNB on the thus configured downlink backhaul,
the ACK/NACK signal (A/N) is sent back from the relay
station RN. Therefore, the uplink backhauls are configured
in the subframe #1 of the Frame_0, the subframe #7 of the
Frame_1, and the subframe #5 of the Frame_2.
On this uplink backhaul, an upstream access link
is incapable of being used. As illustrated in (e) of FIG.
7-2, all the HARQs (performance timing of thick lines)

incapable of being performed belong to the same HARQ
process (namely, the process number PID2).
FIG. 7-3 illustrates the backhaul configuring
method in the case where only the HARQ process of the
process number PID3 is configured as a HARQ process in
which a HARQ is incapable of being partly performed among
the HARQ processes of the process numbers PID1 to PID8.
That is, a HARQ process in which the HARQ is incapable of
being partly performed is limited to the HARQ process of
the process number PID3.
In FIG. 7-3, the downlink backhauls of three times
are secured among the four continuing Frames. Specifically,
in FIG. 7-3, the downlink backhauls are configured in the
subframe #6 of the Frame_0, the subframe #2 of the Frame_2,
and the subframe #8 of the Frame_3. Also, in the same
positions as in the above also in Frames continuous with
the Frame_0 to Frame_3, the downlink backhauls are
configured. After 4 ms of the data transmission from the
base station eNB on the thus configured downlink backhaul,
the ACK/NACK signal is sent back from the relay station RN.
Therefore, the uplink backhauls are configured in the
subframe #2 of the Frame_0, the subframe #0 of the Frame_1,
and the subframe #6 of the Frame_2.
On this uplink backhaul, an upstream access link
is incapable of being used. As illustrated in (e) of FIG.
7-3, all the HARQs (performance timing of thick lines)
incapable of being performed belong to the same HARQ

process (namely, the process number PID3).
FIG. 7-4 illustrates the backhaul configuring
method in the case where only the HARQ process of the
process number PID4 is configured as a HARQ process in
which a HARQ is incapable of being partly performed among
the HARQ processes of the process numbers PID1 to PID8.
That is, a HARQ process in which the HARQ is incapable of
being partly performed is limited to the HARQ process of
the process number PID4.
In FIG. 7-4, the downlink backhauls of three times
are secured among the four continuing Frames. Specifically,
in FIG. 7-4, the downlink backhauls are configured in the
subframe #7 of the Frame_0, the subframe #3 of the Frame_2,
and the subframe #1 of the Frame_3. Also, in the same
positions as in the above also in Frames continuous with
the Frame_0 to Frame_3, the downlink backhauls are
configured. After 4 ms of the data transmission from the
base station eNB on the thus configured downlink backhaul,
the ACK/NACK signal is sent back from the relay station RN.
Therefore, the uplink backhauls are configured in the
subframe #1 of the Frame_l, the subframe #7 of the Frame_2,
and the subframe #5 of the Frame_3.
On this uplink backhaul, an upstream access link
is incapable of being used. As illustrated in (e) of FIG.
7-4, all the HARQs (performance timing of thick lines)
incapable of being performed belong to the same HARQ
process (namely, the process number PID4).

FIG. 7-5 illustrates the backhaul configuring
method in the case where only the HARQ process of the
process number PID5 is configured as a HARQ process in
which a HARQ is incapable of being partly performed among
the HARQ processes of the process numbers PID1 to PID8.
That is, a HARQ process in which the HARQ is incapable of
being partly performed is limited to the HARQ process of
the process number PID5.
In FIG. 7-5, the downlink backhauls of three times
are secured among the four continuing Frames. Specifically,
in FIG. 7-5, the downlink backhauls are configured in the
subframe #8 of the Frame_0, a subframe #6 of the Frame_1,
and a subframe #2 of the Frame_3. Also, in the same
positions as in the above also in Frames continuous with
the Frame_0 to Frame_3, the downlink backhauls are
configured. After 4 ms of the data transmission from the
base station eNB on the thus configured downlink backhaul,
the ACK/NACK signal is sent back from the relay station RN.
Therefore, the uplink backhauls are configured in the
subframe #2 of the Frame_1, the subframe #0 of the Frame_2,
and the subframe #6 of the Frame_3.
On this uplink backhaul, an upstream access link
is incapable of being used. As illustrated in (e) of FIG.
7-5, all the HARQs (performance timing of thick lines)
incapable of being performed belong to the same HARQ
process (namely, the process number PID5).
FIG. 7-6 illustrates the backhaul configuring

method in the case where only the HARQ process of the
process number PID6 is configured as a HARQ process in
which a HARQ is incapable of. being partly performed among
the HARQ processes of the process numbers PID1 to PID8.
That is, a HARQ process "in which the HARQ is incapable of
being partly performed is limited to the HARQ process of
the process number PID6.
In FIG. 7-6, the downlink backhauls of three times
are secured among the four continuing Frames. Specifically,
in FIG. 7-6, the downlink backhauls are configured in the
subframe #1 of the Frame_0, the subframe #7 of the Frame_l,
and the subframe #3 of the Frame_3. Also, in the same
positions as in the above also in Frames continuous with
the Frame_Q to Frame_3, the downlink backhauls are
configured. After 4 ms of the data transmission from the
base station eNB on the thus configured downlink backhaul,
the ACK/NACK signal is sent back from the relay station RN.
Therefore, the uplink backhauls are configured in the
subframe #5 of the Frame 0, the subframe #1 of the Frame_2,
and the subframe #7 of the Frame_3.
On this uplink backhaul, an upstream access link
is incapable of being used. As illustrated in (e) of FIG.
7-6, all the HARQs (performance timing of thick lines)
incapable of being performed belong to the same HARQ
process (namely, the process number PID6).
FIG. 7-7 illustrates the backhaul configuring
method in the case where only the HARQ process of the

process number PID7 is configured as a HARQ process in
which a HARQ is incapable of being partly performed among
the HARQ processes of the process numbers PID1 to PID8.
That is, a HARQ process in which the HARQ is incapable of
being partly performed is limited to the HARQ process of
the process number PID7.
In FIG. 7-7, the downlink backhauls of three times
are secured among the four continuing Frames. Specifically
in FIG. 7-7, the downlink backhauls are configured in the
subframe #2 of the Frame_0, the subframe #8 of the Frame_1,
and the subframe #6 of the Frame_2. Also, in the same
positions as in the above also in Frames continuous with
the Frame_0 to Frame_3, the downlink backhauls are
configured. After 4 ms of the data transmission from the
base station eNB on the thus configured downlink backhaul,
the ACK/NACK signal is sent back from the relay station RN.
Therefore, the uplink backhauls are configured in the
subframe #6 of the Frame_0, the subframe #2 of the Frame_2,
and the subframe #0 of the Frame_3.
On this uplink backhaul, an upstream access link
is incapable of being used. As illustrated in (e) of FIG.
7-7, all the HARQs (performance timing of thick lines)
incapable of being performed belong to the same HARQv
process (namely, the process number PID7).
FIG. 7-8 illustrates the backhaul configuring
method in the case where only the HARQ process of the
process number PID8 is configured as a HARQ process in

which a HARQ is incapable of being partly performed among
the HARQ processes of the process numbers PID1 to PID8.
That is, a HARQ process in which the HARQ is incapable of
being partly performed is limited to the HARQ process of
the process number PID8.
In FIG. 7-8, the downlink backhauls of three times
are secured among the four continuing Frames. Specifically,
in FIG. 7-8, the downlink backhauls are configured in the
subframe #3 of the Frame_0, the subframe #1 of the Frame_l,
and a subframe #7 of the Frame_2. Also, in the same
positions as in the above also in Frames continuous with
the Frame_0 to Frame_3, the downlink backhauls are
configured. After 4 ms of the data transmission from the
base station eNB on the thus configured downlink backhaul,
the ACK/NACK signal is sent back from the relay station RN.
Therefore, the uplink backhauls are configured in the
subframe #7 of the Frame_0, the subframe #5 of the Frame_1,
and the subframe #1 of the Frame_3.
On this uplink backhaul, an upstream access link
is incapable of being used. As illustrated in (e) of FIG.
7-8, all the HARQs (performance timing of thick lines)
incapable of being performed belong to the same HARQ
process (namely, the process number PID8).
As described above, in the backhaul configuring
method according to the present embodiment, the backhaul is
configured in such a manner that the HARQ process in which
the HARQ on an upstream access link is incapable of being

partly performed is limited to one HARQ process.
Accordingly, although the configuration frequency (three
times among four Frames) of the backhaul is relatively
small, the HARQ process in which the HARQ on the upstream
access link is incapable of being partly performed is
integrated:. Further, the complexity of the scheduling is
reduced, and the efficiency of the access link is improved.
(2) Second Embodiment
A backhaul configuring method according to a
second embodiment will be described below.
The backward configuring method according to the
present embodiment is a method of a case where backward
compatibility with the LTE is maintained with regard to
reply timing of the HARQ. Specifically, with regard to the
reply timing of the HARQ, an ACK/NACK signal is here
assumed to be sent back after 4 ms of data transmission.
The present embodiment differs from the first embodiment in
that the configuration frequency of the backhaul is
increased. Through the process, as compared with the first
embodiment, while the configuration frequency of the
backhaul is more increased, the efficiency of the access
link is maintained.
The backhaul configuring method according to the
present embodiment will be specifically described below
with reference to FIGS. 8-1 to 8-8. Formats of FIGS. 8-1
to 8-8' are the same as that of FIG. 6. FIGS. 8-1 to 8-8
illustrate a case where each of the HARQ processes of the

process numbers PID1 to PID8 is a HARQ process in which the
HARQ is incapable of being performed at all timing points.
FIGS. 8-1 to 8-8 further illustrate by thick lines the
timing at which the HARQ is incapable of being performed.
In contradiction to the configuration conditions
illustrated in FIG. 6, In FIGS. 8-1 to 8-8, portions of
subframes incapable of being used as the upstream access
link are displayed to be black-filled by dotted thick frame
lines.
In the backhaul configuring method illustrated in
FIGS. 8-1 to 8-8, a downlink backhaul is each added to the
backhaul configuring method illustrated in FIGS. 7-1 to 7-8,
thereby securing the downlink backhaul of one time in each
Frame. Further, in the backhaul configuring method
illustrated in FIGS. 8-1 to 8-8, the HARQ process in which
the HARQ is incapable of being performed at all the timing
points is each configured, thereby securing the number of
the uplink backhauls more.
In the backhaul configuring method illustrated in
FIG. 8-1, as compared with that illustrated in FIG. 7-1,
the downlink backhaul is newly added and configured in the
subframe #8 of the Frame_0. The downlink backhaul is
configured in the same positions as in the above also in
Frames continuous with the Frame_0 to Frame_3. As a result,
after 4 ms of the data transmission from the base station
eNB on this added and configured downlink backhaul, the
uplink backhaul is configured in the subframe #2 of the

Framel for sending back the ACK/NACK signal from the relay
station RN.
As the HARQ process in which the HARQ is incapable
of being performed at all the timing points, when the HARQ
process of the process number PID1 is further configured,
the number of the uplink backhauls is more secured.
Specifically, correspondingly to the upstream access link
in the HARQ process of the process number PIDl, the uplink
backhauls are configured in the subframe #8 of the Frame_0
and the subframe #4 of the Frame_2. In the added and
configured downlink backhaul (the subframe #8 of the
Frame_0), the uplink backhaul is further configured in the
subframe #.4 of the FrameO before 4 ms so as to receive the
ACK/NACK signal from the base station eNB. For securing
the number of the uplink backhauls more as described above,
the newly configured uplink backhaul having the
configuration condition different from that using as a base
the LTE illustrated in FIG. 6 is controlled by the relay
station RN in such a manner that transmission is not
performed through the upstream access link.
As a result of configuring the downlink backhaul
and the uplink backhaul as described above, as illustrated
in (e) of FIG. 8-1, the HARQ process in which the HARQ is
incapable of being performed is integrated into a part of
the HARQ processes {the PID1 and the PID5 shifted by 4 ms
from the PIDl) . Through the process, the downlink
backhauls of four times and the uplink backhauls of seven

times are capable of being configured for every four Frames.
In the backhaul configuring method illustrated in
FIG. 8-2, as compared with that illustrated in FIG. 7-2,
the downlink backhaul is newly added and configured in the
subframe #1 of the Frame_0. The downlink backhaul is
configured in the same positions as in the above also in
Frames continuous with the Frame__0 to Frame_3. As a result,
after 4 ms of the data transmission from the base station
eNB on this added and configured downlink backhaul, the
uplink backhaul is configured in the subframe #5 of the
Frame_0 for sending back-the ACK/NACK signal from the relay
station RN.
As the HARQ process in which the HARQ is incapable
of being performed at all the timing points, when the HARQ
process of the process number PID2 is further configured,
the number of the uplink backhauls is more secured.
Specifically, correspondingly to the upstream access link
in the HARQ process of the process number PID2, the uplink
backhauls are configured in the subframe #9 of the Frame_0
and the subframe #3 of' the Frame_3. In the added and
configured downlink backhaul (the subframe #1 of the
Frame_0), the uplink backhaul is further configured in the
subframe #7 of the Frame_3 before 4 ms so as to receive the
ACK/NACK signal from the base station eNB. For securing
the number of the uplink backhauls more as described above,
the newly configured uplink backhaul having the
configuration condition different from that using as a base

the LTE illustrated in FIG. 6 is controlled by the relay
station RN in such a manner that transmission is not
performed through the upstream access link.
As a result of configuring the downlink backhaul
and the uplink backhaul as described above, as illustrated
in (e) of FIG. 8-2, the HARQ process in which the HARQ is
incapable of being performed is integrated into a part of
the HARQ processes {the PID2, and the PID6 shifted by 4 ms
from the PID2). Through the process, the downlink
backhauls of four times and the uplink backhauls of seven
times are capable of being configured for every four Frames.
In the backhaul configuring method illustrated in
FIG. 8-3, as compared with that illustrated in FIG. 7-3,
the downlink backhaul is newly added and configured in the
subframe #8 of the Frame_l. The downlink backhaul is
configured in the same positions as in the above also in
Frames continuous with the Frame_0 to Frame_3. As a result,
after 4 ms of the data transmission from the base station
eNB on this added and configured downlink backhaul, the
uplink backhaul is configured in the subframe #2 of the
Frame_2 for sending back the ACK/NACK signal from the relay
station RN.
As the HARQ process in which the HARQ is incapable
of being performed at all the timing points, when the HARQ
process of the process number PID3 is further configured,
the number of the uplink backhauls is more secured.
Specifically, correspondingly to the upstream access link

in the HARQ process of the process number PID3, the uplink
backhauls are configured in the subframe #8 of the Frame_l
and the subframe #4 of the Frame_3. In the added and
configured downlink backhaul (the subframe #8 of the
Frame_l), the uplink backhaul is further configured in the
subframe #4 of the Frame_l before 4 ms so as to receive the
ACK/NACK signal from the base station eNB. For securing
the number of the uplink backhauls more as described above,
the newly configured uplink backhaul having the
configuration condition different from that using as a base
the LTE illustrated in FIG. 6 is controlled by the relay
station RN in such a manner that transmission is not
performed through the upstream access link.
As a result of configuring the downlink backhaul
and the uplink backhaul as described above, as illustrated
in (e) of FIG. 8-3, the HARQ process in which the HARQ is
incapable of being performed is integrated into a part of
the HARQ processes (the PID3, and the PID7 shifted by 4 ms
from the PID3). Through the process, the downlink
backhauls of four times and the uplink backhauls of seven
times are capable of being configured for every four Frames.
In the backhaul configuring method illustrated in
FIG. 8-4, as compared with that illustrated in FIG. 7-4,
the downlink backhaul is newly added and configured in the
subframe #1 of the Frame_l. The downlink backhaul is
configured in the same positions as in the above also in
Frames continuous with the Frame_0 to Frame_3. As a result,

after 4 ms of the data transmission from the base station
eNB on this added and configured downlink backhaul, the
uplink backhaul is configured in the subframe #5 of the
Frame_l for sending back the ACK/NACK signal from the relay-
station RN.
As the HARQ process in which the HARQ is incapable
of being performed at all the timing points, when the HARQ
process of the process number PID4 is further configured,
the number of the uplink backhauls is more secured.
Specifically, correspondingly to the upstream access link
in the HARQ process of the process number PID4, the uplink
backhauls are configured in the subframe #3 of the Frame__0
and the subframe #9 of the Frame_l. In the added and
configured downlink backhaul (the subframe #1 of the
Frame_l), the uplink backhaul is further configured in the
subframe #7 of the Frame_0 before 4 ms so as to receive the
ACK/NACK signal from the base station eNB. For securing
the number of the uplink backhauls more as described above,
the newly configured uplink backhaul having the
configuration condition different from that using as a base
the LTE illustrated in FIG. 6 is controlled by the relay
station RN in such a manner that transmission is not
performed through the upstream access link.
As a result of configuring the downlink backhaul
and the uplink backhaul as described above, as illustrated
in (e) of FIG. 8-4, the HARQ process in which the HARQ is
incapable of being performed is integrated into a part of

the HARQ processes (the PID4, and the PID8 shifted by 4 ms
from the PID4). Through the process, the downlink
backhauls of four times and the uplink backhauls of seven
times are capable of being configured for every four Frames.
In the backhaul configuring method illustrated in
FIG. 8-5, as compared with that illustrated in FIG. 7-5,
the downlink backhaul is newly added and configured in the
subframe #8 of the Frame_2. The downlink backhaul is
configured in the same positions as in the above also in
Frames continuous with the Frame_0 to Frame_3. As a result,
after 4 ms of the data transmission from the base station
eNB on this added and configured downlink backhaul, the
uplink backhaul is configured in the subframe #2 of the
Frame_3 for sending back the ACK/NACK signal from the relay
station RN.
As the HARQ process in which the HARQ is incapable
of being performed at all the timing points, when the HARQ
process of the process number PID5 is further configured,
the number of the uplink backhauls is more secured.
Specifically, correspondingly to the upstream access link
in the HARQ process of the process number PID5, the uplink
backhauls are configured in the subframe #4 of the Frame_0
and the subframe #8 of the Frame_2. In the added and
configured downlink backhaul (the subframe #8 of the
Frame__2), the uplink backhaul is further configured in the
subframe #4 of the Frame_2 before 4 ms so as to receive the
ACK/NACK signal from the base station eNB. For securing

the number of the uplink backhauls more as described above,
the newly configured' uplink backhaul having the
configuration condition different from that using as a base
'the LTE illustrated in FIG. 6 is controlled by the relay
station RN in such a manner that transmission is not
performed through the upstream access link.
As a result of configuring the downlink backhaul
and the uplink backhaul as described above, as illustrated
in (e) of FIG. 8-5, the HARQ process in which the HARQ is
incapable of being performed is integrated into a part of
the HARQ processes (the PID5 and the PID1 shifted by 4 ms
from the PID5). Through the process, the downlink
backhauls of four times and the uplink backhauls of seven
times are capable of being configured for every four Frames.
In the backhaul configuring method illustrated in
FIG. 8-6, as compared with that illustrated in FIG. 7-6,
the downlink backhaul is newly added and configured in the
subframe #1 of the Frame_2. The downlink backhaul is
configured in the same positions as in the above also in
Frames continuous with the Frame_0 to Frame_3. As a result,
after 4 ms of the data transmission from the base station
eNB on this adojed and configured downlink backhaul, the
uplink backhaul is configured in the subframe #5 of the
Frame_2 for sending back the ACK/NACK signal from the relay
station RN.
As the HARQ process in which the HARQ is incapable
of being performed at all the timing points, when the HARQ

process of the process number PID6 is further configured,
the number of the uplink backhauls is more secured.
Specifically, correspondingly to the upstream access link
in the HARQ process of the process number PID6, the uplink
backhauls are configured in the subframe #3 of the Frame_l
and the subframe #9 of the Frame_2. In the added and
configured downlink backhaul (the subframe #1 of the
Frame_2), the uplink backhaul is further configured in the
subframe #7 of the Framel before 4 ms so as to receive the
ACK/NACK signal from the base station eNB. For securing
the number of the uplink backhauls more as described above,
the newly configured uplink backhaul having the
configuration condition different from that using as a base
the LTE illustrated in FIG. 6 is controlled by the relay
station RN in such a manner that transmission is not
performed through the upstream access link.
As a result - of configuring the downlink backhaul
and the uplink backhaul as described above, as illustrated
in (e) of FIG. 8-6, the HARQ process in which the HARQ is
incapable of being performed is integrated into a part of
. the HARQ processes (the PID6 and the PID2 shifted by 4 ms
from the PID6). Through the process, the downlink
backhauls of four times and the uplink backhauls of seven
times are capable of being configured for every four Frames.
In the backhaul configuring method illustrated in
FIG. 8-7, as compared with that illustrated in FIG. 7-7,
the downlink backhaul is newly added and configured in the

subframe #8 of the Frame_3.' The downlink backhaul is
configured in the same positions as in the above also in
Frames continuous with the Frame_0 to Frame_3. As a result,
after 4 ms of the data transmission from the base station
eNB on this added and configured downlink backhaul, the
uplink backhaul is configured in the subframe #2 of the
Frame_0 for sending back "the ACK/NACK signal from the relay
station RN.
As the HARQ process in which the HARQ is incapable
of being performed at all the timing points, when the HARQ
process of the process number PID7 is further configured,
the number of the uplink backhauls is more secured.
Specifically, correspondingly to the upstream access link
in the HARQ process of the process number PID7, the uplink
backhauls are configured in the subframe #4 of the Frame_l
and the subframe #8 of" the Frame_3. In the added and
configured downlink backhaul {the subframe #8 of the
Frame_3), the uplink backhaul is further configured in the
subframe #4 of the Frame_3 before 4 ms so as to receive the
ACK/NACK signal from the base station eNB. For securing
the number of the uplink backhauls more as described above,
the newly configured uplink backhaul having the
configuration condition different from that using as a base
the LTE illustrated in FIG. 6 is controlled by the relay
station RN in such a manner that transmission is not
performed through the upstream access link.
As a result of configuring the downlink backhaul

and the uplink backhaul as described above, as illustrated
in (e) of FIG. 8-7, the HARQ process in which the HARQ is
incapable of being performed is integrated into a part of (
the HARQ processes (the PID7 and the PID3 shifted by 4 ms
from the PID7). Through the process, the downlink
backhauls of four times and the uplink backhauls of seven
times are capable of being configured for every four Frames.
In the backhaul configuring method illustrated in
FIG. 8-8, as compared with that illustrated in FIG. 7-8,
the downlink backhaul is newly added and configured in the
subframe #1 of the Frame_3. The downlink backhaul is
configured in the same positions as in the above also in
Frames continuous with the Frame_0 to Frame_3. As a result,_
after 4 ms of the data transmission from the base station
eNB on this added and configured downlink backhaul, the
uplink backhaul is configured in the subframe #5 of the
Frame_3 for sending back the ACK/NACK signal from the relay
station RN.
As the HARQ process in which the HARQ is incapable
of being performed at all the timing points, when the HARQ
process of the process number PID8 is further configured,
the number of the uplink backhauls is more secured.
Specifically, correspondingly to the upstream access link
in the HARQ process of the process number PID8, the uplink
backhauls are configured in the subframe #3 of the Frame_2
and the subframe #9 of the Frame_3. In the added and
configured downlink backhaul (the subframe #1 of the

Frame_3), the uplink backhaul is further configured in the
subframe #7 of the Frame_2 before 4 ms so as to receive the
ACK/NACK signal from the base station eNB. For securing
the number of the uplink backhauls more as described above,
the newly configured uplink backhaul having the
configuration condition different from that using as a base
the LTE illustrated in FIG. 6 is controlled by the relay
station RN in such a manner that transmission is not
performed through the upstream access link.
As a result of configuring the downlink backhaul
and the uplink backhaul as described above, as illustrated
in (e) of FIG. 8-8, thevHARQ process in which the HARQ is
incapable of being performed is integrated into a part of
the HARQ processes (the PID8 and the PID4 shifted by 4 ms
from the PID8). Through the process, the downlink
backhauls of four times and the uplink backhauls of seven
times are capable of being configured for every four Frames.
FIG. 9 tabulates the backhauls configured by the
backhaul configuring method exemplified in FIGS. 8-1 to 8-8.
In FIG. 9, in the case where values of Configuration are 0
to 7, they correspond to. transmission and reception timing
points set in FIGS. 8-1 to 8-8, respectively. An SFN
(System Frame Number) means a Frame number, and Frames of
the SFN in which SFN mod 4=0, 1, 2, and 3 hold correspond
to the Frames 0, 1, 2, and 3 in FIGS. 8-1 to 8-8,
respectively.
For each value of the Configuration, FIG. 9A

illustrates a subframe #i (i=0, ..., 9) through which the
relay station RN receives the ACK/NACK signal, namely, the
downlink backhaul #i. In the subframe #(i-4) before 4 ms
of the here described subframe #i, the uplink backhaul is
configured.
FIG. 9B illustrates a subframe #i (i=0, ..., 9)
through which the relay station RN transmits the ACK/NACK
signal, namely, an uplink backhaul #i. That is, in the
subframe #(i-4) before 4 ms of the here described subframe
#i, the downlink backhaul is configured. The uplink
backhaul not described in FIG. 9B is appropriately
determined according to a value of each configuration,
namely, the timing of the uplink transmission of the HARQ
process to be integrated.
As can be seen from the above description, in the
backhaul configuring method according to the present
embodiment, a plurality of HARQ processes are integrated
into the HARQ process in which the HARQ is incapable of
being performed for more securing the configuration
frequency of the downlink and uplink backhauls. Through
the process, the configuration frequency of the backhaul is
more increased and the scheduling on the access link of the
relay station RN is easily performed to maintain the
efficiency of the access link. As a result, both of the
above matters are compatible with a high level.
Referring again to FIG. 8-1, for example, the
downlink backhaul is not configured after 4 ms of the

uplink backhaul configured in the subframe #2 of the
Frame_l. Therefore, it is not preferred that on the uplink
backhaul configured in the subframe #2 of the Frame_l/ the
relay station RN transmits data (user data) necessary for a
reply of the ACK/NACK signal to the base station eNB. The
reason is that the downlink backhaul is not configured
after 4 ms of the uplink backhaul configured in the
subframe #2 of the Frame_l. Accordingly, through the
uplink backhaul in which the downlink backhaul is not
configured after 4 ms among the uplink backhauls configured
by using the backhaul configuring method illustrated in
FIGS. 8-1 to 8-8, the relay station RN transmits data
unnecessary for a reply of the ACK/NACK signal from the
base station eNB. Examples of the data unnecessary for a
reply of the ACK/NACK signal include data for a CQI
(Channel Quality Indicator) report.
Although there is limited a data type to be
transmitted through a part of the configured uplink
backhaul, data to be transmitted through each uplink
backhaul is appropriately managed, thereby securing the
configuration frequency of the uplink backhaul more.
(3) Third Embodiment
A backhaul configuring method according to a third
embodiment will be described below.
In the second embodiment, there is illustrated an
example in which a backhaul is added to the backhauls
configured according to the first embodiment and the

downlink backhaul is secured in each Frame. However, the
downlink backhaul is arbitrarily configured in each frame.
Assume specifically that with regard to the reply timing of
the HARQ, the ACK/NACK signal is sent back after 4 ms of
the data transmission. At the same time, the backhaul is
preferably configured in such a manner that the number of
the HARQ processes in which the HARQ is incapable of being
performed partly or wholly is reduced as much as possible.
An example in which the proposed backhaul configuring"
method is different from that according to the second
embodiment will be described below.
The backhaul configuring method according to the
present embodiment will be specifically described below
with reference to FIGS. 10-1 to 10-8. Formats of FIGS. 10-"
1 to 10-8 are the same as that of FIG. 6. FIGS. 10-1 to
10-8 each illustrate a case where the HARQ process in which
the HARQ is incapable of being partly performed stands in
the HARQ processes of the process numbers PID1 to PID8 and
the HARQ processes of the process numbers PID5 to PID4
shifted after 4 ms of the above HARQ processes. FIGS. 10-1
to 10-8 further illustrate by using thick lines the timing
points at which the HARQ is incapable of being performed.
The backhaul configuring method illustrated in
FIGS. 10-1 to 10-8 differs from that illustrated in FIGS."'
8-1 to 8-8 in that two HARQ processes in which the HARQ is
incapable of being partly performed are configured.
In FIG. 10-1, the downlink backhauls are secured

in each of the four continuing frames. Specifically, in
FIG. 10-1, in the subframe #8 of the Frame_0, the subframe
#6 of the Frame_l, the subframe #8 of the Frame_2, and the
subframe #6 of the Frame_3, the downlink backhauls are
configured. Also, with relation to Frames continuous with
the Frame_0 to Frame_3, the downlink backhauls are
configured in the same position as in the above. After 4
ms of the data transmission from the base station eNB
through the thus configured downlink backhauls, for sending
back the ACK/NACK signal from the relay station RN, the
uplink backhauls are configured in the subframe #2 of the
Frame 1, the subframe #0 of the Frame_2, the subframe #2 of
the Frame_3, and the subframe #0 of the Frame_0.
Here, as a HARQ process in which the HARQ is
incapable of being partly performed, there are configured
the HARQ process of the process number PID1 and the HARQ
process of the process number PID5 shifted after 4 ms from
the HARQ process of the process number PID1. Through the
process, the number of the uplink backhauls is more secured.
Specifically, the uplink backhauls are configured in the
subframe #4 of the Frame_2 corresponding to the upstream
access link in the HARQ process of the process number PIDl,
and the subframe #4 of the Frame_0 corresponding to the
upstream access link in the HARQ process of the process
number PID5. A part of the configured uplink backhauls
having the configuration condition different from that
using as a base the LTE illustrated in FIG. 6 are

controlled by the relay station RN in such a manner that-
transmission is not performed through the upstream access
link.
As a result of configuring the downlink backhauls
and the uplink backhauls as described above, as illustrated
in (e) of FIG. 10-1, the HARQ processes in which the HARQ
is incapable of being partly performed are integrated into
a part of the HARQ processes (PID1 and the PID5 shifted by
4 ms from the PIDl). Through the process, the downlink
backhauls of four times and the uplink backhauls of six
times are capable of being configured for every four Frames.-
In FIG. 10-2, the downlink backhauls are secured
in each of the four continuing frames. Specifically, in
FIG. 10-2, in the subframe #1 of the Frame_0, the subframe
#3 of the Frame_l, the subframe #1 of the Frame_2, and the
subframe #3 of the Frame_3, the downlink backhauls are
configured. Also, with relation to Frames continuous with
the Frame_0 to Frame_3, the downlink backhauls are
configured in the same position as in the above. After 4
ms of the data transmission from the base station eNB
through the thus configured downlink backhauls, for sending-
back the ACK/NACK signal from the relay station RN, the
uplink backhauls are configured in the subframe #5 of the
Frame_0, the subf rame #7 of the Frame 1, the subframe #5 of
the Frame_2, and the subframe #7 of the Frame_3.
Here, as a HARQ process in which the HARQ is.
incapable of being partly performed, there are configured

the HARQ process of the-process number PID2 and the HARQ
process of the process number PID6 shifted after 4 ms from
the HARQ process of the process number PID2. Through the
process, the number of the uplink backhauls is more secured.
Specifically, the uplink backhauls are configured in the"
subframe #9 of the Frame_0 corresponding to the upstream
access link in the HARQ process of the process number PID2,
and the subframe #9 of the Frame_2 corresponding to the
upstream access link in the HARQ process of the process
number PID6. A part of the configured uplink backhauls''
having the configuration condition different from that
using as a base the LTE illustrated in FIG. 6 are
controlled by the relay station RN in such a manner that
transmission is not performed through the upstream access
link.
As a result of configuring the downlink backhauls
and the uplink backhauls as described above, as illustrated
in (e) of FIG. 10-2, the HARQ processes in which the HARQ
is incapable of being partly performed are integrated into
a part of the HARQ processes (PID2 and the PID6 shifted by"
4 ms from the PID2). Through the process, the downlink
backhauls of four times and the uplink backhauls of six
times are capable of being configured for every four Frames.
In FIG. 10-3, the downlink backhauls are secured
in each of the four continuing frames. Specifically, in
FIG. 10-3, in the subframe #6 of the Frame_0, the subframe
#8 of the Frame__l, the subframe #6 of the Frame_2, and the

subframe #8 of the Frame_3, the downlink backhauls are
configured. Also, with relation to Frames continuous with
the Frame_0 to Frame_3, the downlink backhauls are
configured in the same position as in the above. After 4
ms of the data transmission from the base station eNB
through the thus configured downlink backhauls, for sending
back the ACK/NACK signal from the relay station RN, the
uplink backhauls are configured in the subframe #0 of the ,
Frame_l, the subframe #2 of the Frame_2, the subframe #0 of
the Frame_3, and the subframe #2 of the Frame__0.
Here, as a HARQ process in which the HARQ is
incapable of being partly performed, there are configured
the HARQ process of the process number PID3 and the HARQ ...
process of the process number PID7 shifted after 4 ms from
the HARQ process of the process number PID3. Through the
process, the number of the uplink backhauls is more secured.
Specifically, the uplink backhauls are configured in the
subframe #4 of the Frame_3 corresponding to the upstream ,
B
access link in the HARQ process of the process number PID3,
and the subframe #4 of the Frame_l corresponding to the
upstream access link in the HARQ process of the process
number' PID7. A part of the configured uplink backhauls
having the configuration condition different from that
using as a base the LTE illustrated in FIG. 6 are
controlled by the relay station RN in such a manner that
transmission is not performed through the upstream access
link.

As a result of configuring the downlink backhauls
and the uplink backhauls as described above, as illustrated. -
in (e) of FIG. 10-3, the HARQ processes in which the HARQ
is incapable of being partly performed are integrated into
a part of the HARQ processes (PID3 and the PID7 shifted by
4 ms from the PID3) . Through the process, the downlink
backhauls of four times and the uplink backhauls of six'
times are capable of being configured for every four Frames.
In FIG. 10-4, the downlink backhauls are secured
in each of the four continuing frames. Specifically, in
FIG. 10-4, in the subframe #3 of the Frame_0, the subframe
#1 of the Frame_l, the subframe #3 of the Frame_2, and the,'
subframe #1 of the Frame_3, the downlink backhauls are
configured. Also, with relation to Frames continuous with
the Frame_0 to Frame3, the downlink backhauls are
configured in the same position as in the above. After 4
ms of the data transmission from the base station eNB, -
through the thus configured downlink backhauls, for sending
back the ACK/NACK signal from the relay station RN, the
uplink backhauls are configured in the subframe #7 of the
Frame_0, the subframe #5 of the Frame_l, the subframe #7 of
the Frame_2, and the subframe #5 of the Frame_3. . -
Here, as a HARQ process in which the HARQ is
incapable of being partly performed, there are configured
the HARQ process of the process number PID4 and the HARQ
process of the process number PID8 shifted after 4 ms from
the HARQ process of the process number PID4. Through the -

process, the number of the uplink backhauls is more secured.
Specifically, the uplink backhauls are configured in the
subframe #9 of the Frame_l corresponding to the upstream
access link in the HARQ process of the process number PID4,
and the subframe #9 of the Frame_3 corresponding to the
upstream access link in the HARQ process of the process
number PID8. A part of the configured uplink backhauls
having the configuration condition different from that
using as a base the LTE illustrated in FIG. 6 are
controlled by the relay station RN in such a manner that
transmission is not performed through the upstream access
link.
As a result of configuring the downlink backhauls
and the uplink backhauls as described above, as illustrated
in (e) of FIG. 10-4, the HARQ processes in which the HARQ
is incapable of being partly performed are integrated into
a part of the HARQ processes (PID4 and the PID8 shifted by
4 ms from the PID4). Through the process, the downlink
backhauls of four times and the uplink backhauls of six
times are capable of being configured for every four Frames.
In FIG. 10-5, the downlink backhauls are secured
in each of the four continuing frames. Specifically, in
FIG. 10-5, in the subframe #8 of the Frame_0, the subframe
#6 of the Frame_l, the subframe #8 of the Frame_2, and the
subframe #6 of the Frame_3, the downlink backhauls are
configured. Also, with relation to Frames continuous with
the Frame_0 to Frame_3, the downlink backhauls are

configured in the same position as in the above. After 4
ms of the data transmission from the base station eNB
through the thus configured downlink backhauls, for sending
back the ACK/NACK signal from the relay station RN, the
uplink backhauls are configured in the subframe #2 of the
Frame_l, the subframe #0 of the Frame_2, the subframe #2 of
the Frame_3, and the subframe #0 of the Frame_0.
Here, as a HARQ process in which the HARQ is
incapable of being partly performed, there are configured
the HARQ process of the process number PID5 and the HARQ
process of the process number PID1 shifted after 4 ms from
the HARQ process of the process number PID5. Through the
process, the number of the uplink backhauls is more secured.
Specifically, the uplink backhauls are configured in the
subframe #4 of the Frame_0 corresponding to the upstream
access link in the HARQ process of the process number PID5,
and the subframe #4 of the Frame__2 corresponding to the
upstream access link in the HARQ process of the process
number PIDl. A part of the configured uplink backhauls
having the configuration condition different from that
using as a base the LTE illustrated in FIG. 6 are
controlled by the relay station RN in such a manner that
transmission is not performed through the upstream access
link.
As a result of configuring the downlink backhauls
and the uplink backhauls as described above, as illustrated
in (e) of FIG. 10-5, the HARQ processes in which the HARQ

is incapable of being partly performed are integrated into
a part of the HARQ processes (PID5 and the PID1 shifted by
4 ms from the PID5) . Through the process, the downlink
backhauls of four times and the uplink backhauls of six
times are capable of being configured for every four Frames.
In FIG. 10-6, the downlink backhauls are secured
in each of the four continuing frames. Specifically, in
FIG. 10-6, in the subframe #1 of the Frame_0, the subframe .,
#3 of the Frame_l, the subframe #1 of the Frame_2, and the
subframe #3 of the Frame_3, the downlink backhauls are
configured. Also, with relation to Frames continuous with
the Frame_0 to Frame_3, the downlink backhauls are
configured in the same position as in the above. After 4 -
ms of the data transmission from the base station eNB
through the thus configured downlink backhauls, for sending
back the ACK/NACK signal from the relay station RN, the
uplink backhauls are configured in the subframe #5 of the
Frame_0, the subframe #7 of the Frame_l, the subframe #5 of
the Frame_2, and the subframe #7 of the Frame_3.
Here, as a HARQ process in which the HARQ is
incapable of being partly performed, there are configured
the HARQ process of the process number PID6 and the HARQ
process of the process number PID2 shifted after 4 ms from ■
the HARQ process of the process number PID6. Through the
process, the number of the uplink backhauls is more secured.
Specifically, the uplink backhauls are configured in the
subframe #9 of the Frame__2 corresponding to the upstream

access link in the HARQ process of the process number PID6,
and the subframe #9 of the Frame_0 corresponding to the
upstream access link in the HARQ process of the process
number PID2. A part of the configured uplink backhauls
having the configuration condition different from that
using as a base the LTE illustrated in FIG. 6 are
controlled by the relay station RN in such a manner that
transmission is not performed through the upstream access
link.
As a result of configuring the downlink backhauls
and the uplink backhauls as described above, as illustrated
in (e) of FIG. 10-6, the HARQ processes in which the HARQ ~'
is incapable of being partly performed are integrated into
a part of the HARQ processes (PID6 and the PID2 shifted by
4 ms from the PID6). Through the process, the downlink
backhauls of four times and the uplink backhauls of six
times are capable of being configured for every four Frames."
In FIG. 10-7, the downlink backhauls are secured
in each of the four continuing frames. Specifically, in
FIG. 10-7, in the subframe #6 of the Frame_0, the subframe
#8 of the Frame__l, the subframe #6 of the Frame_2, and the
subframe #8 of the Frame_3, the downlink backhauls are "
configured. Also, with relation to Frames continuous with
the Frame_0 to Frame_3, the downlink backhauls are
configured in the same position as in the above. After 4
ms of the data transmission from the base station eNB
through the thus configured downlink backhauls, for sending '"

back the ACK/NACK signal from the relay station RN, the
uplink backhauls are configured in the subframe #0 of the
Frame_l, the subframe #2 of the Frame_2, the subframe #0 of
the Frame_3, and the subframe #2 of the Frame_0.
Here, as a HARQ process in which the HARQ is :
incapable of being partly performed, there are configured
the HARQ process of the process number PID7 and the HARQ
process of the process number PID3 shifted after 4 ms from
the HARQ process of the process number PID7. Through the
process, the number of the uplink backhauls is more secured.f
Specifically, the uplink backhauls are configured in the
subframe #4 of the Frame_l corresponding to the upstream
access link in the HARQ process of the process number PID7,
and the subframe #4 of the Frame_3 corresponding to the
upstream access link in the HARQ process of the process
number PID3. A part of the configured uplink backhauls
having the configuration condition different from that
. using as a base the LTE illustrated in FIG. 6 are
controlled by the relay station RN in such a manner that
transmission is not performed through the upstream access
link.
As a result of configuring the downlink backhauls
and the uplink backhauls as described above, as illustrated
in (e) of FIG. 10-7, the HARQ processes in which the HARQ
is incapable of being partly performed are integrated into
a part of the HARQ processes (PID7 and the PID3 shifted by
4 ms from the PID7) . Through the process, the downlink

backhauls of four times and the uplink backhauls of six
times are capable of being configured for every four Frames.
In FIG. 10-8, the downlink backhauls are secured
in each of the four continuing frames. Specifically, in
FIG. 10-8, in the subframe #3 of the Frame_0, the subframe
#1 of the Frame_l, the subframe #3 of the Frame_2, and the
subframe #1 of the Frame_3, the downlink backhauls are
configured. Also, with relation to Frames continuous with
the Frame_0 to Frame_3, the downlink backhauls are s
configured in the same position as in the above. After 4
ms of the data transmission from the base station eNB
through the thus configured downlink backhauls, for sending
back the ACK/NACK signal from the relay station RN, the
uplink backhauls are configured in the subframe #7 of the ...
Frame_0, the subframe #5 of the Frame_l, the subframe #7 of
the Frame_2, and the subframe #5 of the Frame_3.
Here, as a HARQ process in which the HARQ is
incapable of being partly performed, there are configured
the HARQ process of the process number PID8 and the HARQ
process of the process number PID4 shifted after 4 ms from
the HARQ process of the process number PID8. Through the
process, the number of the uplink backhauls is more secured.
Specifically, the uplink backhauls are configured in the
subframe #9 of the Frame__3 corresponding to the upstream,
access link in the HARQ process of the process number PID8,
and the subframe #9 of the Frame_l corresponding to the
upstream access link in the HARQ process of the process

number PID4. A part of the configured uplink backhauls
having the configuration condition different from that
using as a base the LTE illustrated in FIG. 6 are controlled by the relay station RN in such a manner that
transmission is not performed through the upstream access
link.
As a result of configuring the downlink backhauls
and the uplink backhauls as described above, as illustrated
in (e) of FIG. 10-8, the HARQ processes in which the HARQ
is incapable of being partly performed are integrated into
a part of the HARQ processes (PID8 and the PID4 shifted by
4 ms from the PID8). Through the process, the downlink
backhauls of four times and the uplink backhauls of six
times are capable of being configured for every four Frames. .
FIG. 11 tabulates the backhauls configured by the
backhaul configuring method exemplified in FIGS. 10-1 to
10-8. In FIG. 11, in the case where values of the
Configurations are from 0 to 7, they correspond to "
transmission and reception timing points set in FIGS. 10-1
to 10-8, respectively. Frames of the SFNs in which the SFN
mod .4=0, 1, 2, and 3 hold correspond to the Frames_0, 1, 2,
and 3 in FIGS. 10-1 to 10-8, respectively.
For each value of the Configurations, FIG. 11A
illustrates a subframe #i (i=0, ..., 9) through which the
relay station RN receives the ACK/NACK signal, namely, the
downlink backhaul #i. In the subframe #(i-4) before 4 ms
of the here described subframe #i, the uplink backhaul is

configured.
FIG. 11B illustrates a subframe #i (i=0, ..., 9)
through which the relay station RN transmits the ACK/NACK
signal, namely, the uplink backhaul #i. In other words,
the downlink backhaul is configured in the subframe #(i-4)
before 4 ms of the here described subframe #i. The uplink
backhauls not described in FIG. 11B are appropriately
determined according to each value of the Configurations,
namely, the timing of the uplink transmission of the HARQ
process to be integrated.
As described above, in the backhaul configuring
method according to the present embodiment, for securing
the configuration frequency of the downlink and uplink
backhauls as much as possible, a plurality of HARQ
processes are integrated into the HARQ process in which the
HARQ is incapable of being performed. Through the process,
in the same manner as in the second embodiment, the
configuration frequency of the backhaul is more increased
and the scheduling on the access link of the relay station
RN is easily performed to maintain the efficiency of the
access link. As a result, both of the above matters are ,
compatible with a high level.
{4) Fourth Embodiment
A backhaul configuring method according to a
fourth embodiment will be described below.
In the first to third embodiments, the backhaul
configuring method is described assuming that the backward

compatibility with the LTE is maintained with regard to
reply timing of the HARQ. Specifically, in the first to
third embodiments, the ACK/NACK signal is assumed to be
sent back after 4 ms of the data transmission. However,
when the backward compatibility with the LTE is not assumed,/
the efficiency of the access link may be improved by a
method different from those described in the first to third
embodiments.
Assume that, in the present embodiment, since the
specifications are different from those of the LTE, the J~
ACK/NACK signal is sent back after 4 ms of the downlink
data transmission, and the ACK/NACK signal is sent back
after 6 ms of the uplink data transmission. According to
this assumption, as exemplified in FIG. 5, a position of
the downlink backhaul and that of the uplink backhaul are /'"'
always made constant in each Frame. In FIG. 5, an example
in which the downlink backhaul is configured in the
subframe #1 is illustrated; however, it is not limited
thereto. As far as the uplink backhaul is configured after
4 ms of the downlink backhaul, the downlink backhaul may be /'
configured in an arbitrary position of one Frame.
As illustrated in FIG. 5, in the case where the
downlink backhaul is configured in the subframe #1, it is
as described previously that the HARQ is incapable of being
performed due to the timing of a part of the respective /
HARQ processes of the process numbers PID2, PID4, PID6, and
PID8. In the present embodiment, a duration in which this

HARQ is incapable of being performed is configured in the
Measurement gap specified by the LTE.
As described in the non-patent literature 3, the
Measurement gap is composed of a duration of 6 ms in the'
downlink transmission direction and a duration of 7 ms in
the uplink transmission direction provided for a handover
of the mobile station UE. As an interval of the
Measurement gap, for example, 40 ms is specified. In this
Measurement gap, the mobile station UE switches a reception '>■
frequency, and performs radio quality measurement of a
frequency band different from that of the relay station RN
with which the mobile station UE communicates at present.
That is, since the uplink transmission is performed from
the mobile station UE to the relay station RN in the •■■
Measurement gap, there is no trouble even if the HARQ is
incapable of being performed in the Measurement gap.
FIG. 12 illustrates durations of the Measurement
gap at the time when the backhaul is configured at the
timing illustrated in FIG. 5. FIG. 12 differs from FIG. 5-
in that duration of the Measurement gap is added. As an
example, (f) of FIG. 12 illustrates durations of the
Measurement gaps of the mobile stations UEl to UE4.
Each mobile station UE connected to the relay
station RN is allocated to any of the HARQ processes of the '■-
process numbers PID1 to PID8. In the present embodiment,
with respect to the mobile station UE allocated to the HARQ
process including the duration in which the HARQ is

incapable of being performed, the duration in which the
HARQ is incapable of being performed is configured in the
duration of the Measurement gap. Suppose, for example,
that in an example illustrated in FIG. 12, the mobile
station UE1 is allocated to the process number PID6. At
this time, the duration of the Measurement gap including
the duration of the subframes #5 to #9 of the Frame 0 is
configured to the mobile station UE1. In the example
illustrated in FIG. 12, the mobile stations UE2, UE3, and
UE4 are allocated to the process numbers PID8, PID2, and
PID4, respectively, and the duration of the Measurement gap
is configured in the same manner.
In the backhaul configuring method according to
the present embodiment, the configuration itself of the
backhaul is performed by the same method as those of the
foregoing first to third embodiments. In the present
embodiment, the duration of the Measurement gap including
V," •
the duration in which the HARQ is incapable of being
performed is further configured to the mobile station UE.
That is, since the Measurement gap is configured in the
duration in which the access link is incapable of being
used, while the configuration frequency of the backhaul is
more secured, each mobile station UE maintains the
efficiency of the access link.
The configuration of the backhaul illustrated in
FIG. 12 is simply one example for describing the present
embodiment. The duration of the Measurement gap including

the duration in which the HARQ is incapable of being
performed is preferably configured to the mobile station UE
allocated to the HARQ process including the HARQ incapable
of being performed, irrespective of a position in one Frame
of the backhaul. Accordingly, configuration of the
duration of the Measurement gap according to the present
embodiment is apparently applicable to the foregoing first
to third embodiments. Namely, the above configuration is
applicable also to a case where reply timing of the
ACK/NACK signal of the LTE is maintained. In the backhaul
configuring method illustrated in FIG. 8-1, for example, ,
the duration of the Measurement gap including the duration
{the duration in which the HARQ is incapable of being
performed) from the subframe #4 of the Frame_0 to the
subframe #6 of the Frame_l is configured to the mobile
station UE allocated to the process number PID5.
(5) Fifth Embodiment
A relay station RN and mobile station UE according
to a fifth embodiment will be described below.
In the present embodiment, configurations and
operations of the relay station RN and mobile station UE
for performing processes of the foregoing first to fourth
embodiments will be described.
(5-1) Configuration of relay station RN
FIG. 13 is a block diagram illustrating a
schematic configuration of the relay station RN.
As illustrated in FIG. 13, the relay station RN

according to the present embodiment relays radio
communication between the base station eNB and the mobile
station UE. This relay station RN includes transmission
and reception units 31 and 32, a Uu HARQ unit 35, a Un HARQ
unit 36, and a control unit 40. The control unit 40 v
includes a backhaul management unit 45, an access link
management unit 46, and a HARQ management unit 47.
The transmission and reception unit 31 {first
transmission and reception unit) performs transmission and
reception processing between the relay station RN and the
base station eNB. The transmission and reception unit 32
(second transmission and reception unit) performs
transmission and reception processing between the relay
station RN and the mobile station UE. In this relay
station RN, at the time of relay of the radio communication "•
between the base station eNB and the mobile station UE,
demodulation and decoding are performed once to received
signals. Data signals of the demodulated and decoded
received signals are scheduled, and then coded and
modulated again for transmission. In the case where a >
downlink signal is an OFDM signal, for example, the
transmission and reception unit 32 FFT-processes an OFDM
signal received from the base station eNB to separate a
data signal of a subcarrier unit, and subjects the data
signal to demodulation and decoding processing. The data
signal is subjected to coding and modulation processing
again, and mapped to a predetermined radio frame format by

a scheduler 33. The transmission and reception unit 31
performs conversion to a time area signal in each
subcarrier (IFFT processing), synthesis processing of a
time area signal, and CP {Cyclic Prefix) additional
processing.
The Uu HARQ unit 35 performs HARQ relating to data
transmission and reception between the relay station RN and
the mobile station UE. Since the HARQ processing is
previously known, detailed description will not be repeated
here. At the time of the data transmission to the mobile
station UE, for example, the Uu HARQ unit 35 generates data
blocks obtained by subjecting information bits to error-
correction-coding. In the case where the data blocks are
not correctly received by the mobile station UE (in the
case where the transmission and reception unit 31 receives
the NACK signal), the Uu HARQ unit 35 then performs a
process of generating other data blocks based on the same
information bits. These data blocks are transmitted from
the transmission and reception unit 31. The Uu HARQ unit-
35 then generates to the mobile station UE the ACK/NACK
signal as an acknowledgment of data from the mobile station
UE. This ACK/NACK signal is transmitted from the
transmission and reception unit 31.
In the same manner as in the Uu HARQ unit 35, the
Un HARQ unit 36 performs the HARQ relating to the data
transmission and reception between the relay station RN and
the base station eNB.

The transmission and reception unit 32 of the
relay station RN receives from the base station eNB a
backhaul configuration message having described therein
data (refer to FIGS. 9 and 11) of the configuration
relating to the configuration of the backhaul. The
backhaul management unit 45 of the control unit 40 then
configures and manages the backhaul between the relay-
station RN and the base station eNB based on the data of
the configuration included in the backhaul configuration
message. The backhaul configuration message is transferred
to the mobile station UE connected to the relay station RN.
The access link management unit 46 of the control
unit 40 refers to the duration of the backhaul configured
by the backhaul management unit 45, and establishes the
downlink backhaul to an MBSFN subframe. The access link1
management unit 4 6 further manages a UL grant (UL grant to
be transmitted by PDCCH) in such a manner that the mobile
station UE does not perform the uplink data transmission
through the uplink backhaul configured by the backhaul
management unit 4 5 and the UL grant is not given before 4
ms of the uplink backhaul.
The access link management unit 46 as a first
measurement duration management unit configures in the
mobile station UE allocated to the HARQ process the
Measurement gap calculated by the HARQ management unit 47,
including the duration in which the HARQ is incapable of
being performed in a particular HARQ process. As a message

to the mobile station UE, the access link management unit
4 6 generates a Measurement gap configuration message having
described therein information on the duration of the
Measurement gap.
The HARQ management unit 47 as a first
communication management unit manages the HARQ process in a
TTI unit of the subframe. The HARQ management unit 47
allocates the HARQ processes of the process numbers PID1 to
PID8 to each connected mobile station UE. Based on the
backhaul configuration message received from the base
station eNB, the HARQ management unit 47 further calculates
the HARQ process unused on the access link between the
relay station RN and the mobile station UE, and the
duration in which the HARQ is incapable of being performed
in the HARQ process.
(5-2) Configuration of mobile station UE
FIG. 14 is a block diagram illustrating a
schematic configuration of the mobile station UE.
As illustrated in FIG. 14, the mobile station UE
according to the present embodiment performs transmission
and reception of radio .communication between the mobile
station UE and the relay station RN. This mobile station
UE includes a transmission and reception unit 61 and a
control unit 70. The control unit 70 includes a Uu HARQ
management unit 75 (second communication management unit)
and a Measurement gap management unit 7 6 (second
measurement duration management unit).

The transmission and reception unit 61 performs
transmission and reception processing between its own
station and any of the relay station RN and the base
station eNB. The transmission and reception processing of
the transmission and reception unit 61 is the same as that
of the relay station RN. Based on the data of the
configuration received through the transmission and
reception unit 61 from the relay station RN, among the HARQ
processes allocated to its own station, the Uu HARQ
management unit 75 calculates the duration in which the
HARQ is incapable of being performed and manages
communication timing through the access link between its
own station and the relay station RN. The Measurement gap
management unit 76 configures (allocates) the duration of
the Measurement gap based on the duration described in the
Measurement gap configuring message received from the relay
station RN. The Measurement gap management unit 76 further
switches a reception frequency in this duration, and
performs measurement processing of signals in a frequency
band different from that of the relay station RN with which
its own station communicates at present.
(5-3) Operation of relay station RN
Referring next to FIGS. 15 and 16, one example of
operations of the relay station RN relating to the backhaul
configuration will be mainly described. FIGS. 15 and 16
are flowcharts illustrating one example of operations of
the relay station RN. The flowchart of FIG. 15 illustrates

operations of the relay station RN corresponding to the
second and third embodiments, and the flowchart of FIG. 16
illustrates operations of the relay station RN
corresponding to the fourth embodiment.
Referring first to FIG. 15, the transmission and
reception unit 32 of the relay station RN receives the
backhaul configuration message from the base station eNB
(Step S10). The backhaul management unit 45 acquires the
data of the Configuration (refer to FIGS. 9 and 11)
described in the backhaul configuration message (Step S12).
Based on the data of the acquired Configuration, the
backhaul management unit 45 configures the downlink
backhaul and the uplink backhaul in each Frame according to
a value of the SFN mod 4. Next, the access link management
unit 4 6 configures the DL subframe according to the data
(e.g., FIG. 9A) of the Configuration acquired at step S12,
namely, the MBSFN subframe (Step S14) . The access link
management unit 4 6 further configures the uplink backhaul
according to the data (e.g. , FIG. 9B) of the Configuration
acquired at step S12, and controls a stoppage of the UL
grant (UL grant transmitted by the PDCCH) to the mobile
station UE before 4 ms of the uplink backhaul (Step S16).
Based on the data of the configuration acquired at step S12,
the HARQ management unit 47 calculates the HARQ process
which is unused on the access link between its own station
and the mobile station UE (Step S18).
Referring next to FIG. 16, processes of steps S30

and S32 are added to the flowchart of FIG. 15. At step S30,
the access link management unit 46 configures the
Measurement gap including the duration in which the HARQ is
incapable of being performed in the particular HARQ process
to the mobile station UE allocated to the HARQ process
(Step S30) . The transmission and reception unit 31 then
transmits to the corresponding mobile station UE the
Measurement gap configuration message including information
on the duration of the Measurement gap configured at step
S30 (Step S32).
(5-4) Operation of mobile station UE
Referring next to FIGS. 17 and 18, one example of
operations of the mobile station UE will be described.
FIGS. 17 and 17 are flowcharts illustrating one example of
operations of the mobile station UE. The flowchart of FIG.
17 illustrates operations of the mobile station UE
corresponding to the second and third embodiments, and the
flowchart of FIG. 18 illustrates operations of the mobile
station UE corresponding to the fourth embodiment.
Referring first to FIG. 17, the transmission and
reception unit 61 of the mobile station UE receives the
backhaul configuration message transmitted from the relay
station RN (Step S20) . The Uu HARQ management unit 75 of
the control unit 70 acquires the data of the Configuration
described in the backhaul configuration message acquired at
step S20 (Step S22) . Based on the data of the
configuration acquired at step S22, the Uu HARQ management

unit 75 further calculates the duration in which the HARQ
is incapable of being performed among the HARQ processes
allocated to its own station (Step S24) .
Referring next to FIG. 18, steps S40 to S44 are
added to the flowchart of FIG. 17. The transmission and
reception unit 61 of the mobile station UE receives the
Measurement gap configuration message {Step S40). The
Measurement gap management unit 7 6 configures the duration
of the Measurement gap described in the Measurement gap
configuration message received at step S40 (Step S42). In
the duration of this Measurement gap, the mobile station UE
measures a signal in the frequency band different from that
of the relay station RN with which its own station
communicates at present. Based on the data of the
Configuration described in the backhaul configuration
message acquired at step S20, the Measurement gap
management unit 7 6 further confirms whether the downlink
and uplink backhauls are included in the duration of the
Measurement gap configured at step S42 (Step S44).
The present embodiment of the invention is
described in detail, and it is to be understood that the
communication duration configuring method, relay station RN,
mobile station UE, and mobile communication system of the
invention are not limited to the above embodiment and that
various changes and modifications may be made without
departing from the scope of the invention.

Reference Signs List
RN Relay station
31, 32 Transmission and reception unit
35 Uu HARQ unit
36 Un HARQ unit
40 Control unit
4 5 Backhaul management unit
4 6 Access link management unit
47 HARQ management unit
UE Mobile station
61 Transmission and reception unit
70 Control unit
7 5 Uu HARQ management unit
7 6 Measurement gap management unit

CLAIMS
[Claim 1] A communication duration configuring method for
use in a mobile communication system including a relay
station which relays radio communication between a base
station and a mobile station, the communication duration
configuring method comprising:
configuring at least one of a downlink
communication duration in which the relay station receives
a transmission signal from the base station while limiting
transmission of a signal from the relay station to the
mobile station and an uplink communication duration in
which the relay station transmits a transmission signal to
the base station while limiting transmission of a signal
from the mobile station to the relay station;
providing a plurality of communication processes
in which first communication processing including data
transmission and an acknowledgment after a predetermined
first time period from the data transmission is managed on
an access link between the mobile station and the relay
station;
configuring the uplink communication duration at
timing according to the timing of uplink data transmission
of a particular first communication process among the
plurality of communication processes; and
configuring a downlink communication duration
before the predetermined first time period of each of

configured uplink communication durations.
[Claim 2] The communication duration configuring method
according to claim 1, further comprising allocating a
duration in which the first communication processing is
incapable of being performed among the plurality of
communication processes to a measurement period for
measuring, by the mobile station, a radio signal of a
frequency different from- a communication frequency between
the relay station and the mobile station.
[Claim 3] The communication duration configuring method
according to claim 1 or 2, further comprising allocating at
least a part of the configured uplink communication
duration to the uplink data transmission that needs no
acknowledgement from the base station.
[Claim 4] A relay station to be movable and to relay
radio communication between a base station and a mobile
station, the relay station comprising:
a first transmission and reception unit to
transmit and receive a signal between the relay station and
the base station;
a second transmission and reception unit to
transmit and receive a signal between the relay station and
the mobile station;
a control unit to configure at least one of a

downlink communication duration in which the first
transmission and reception unit receives a transmission
signal from the base station while the second transmission
and reception unit limits transmission of a signal to the
mobile station and an uplink communication duration in
which the first transmission and reception unit transmits a
transmission signal to the base station while the mobile
station limits transmission of a signal to the relay
station; and
a first communication management unit to manage a
plurality of communication processes in which first
communication processing including data transmission and an
acknowledgment after a predetermined first time period from
the data transmission is provided on an access link between
the mobile station and the relay station,
wherein the control unit configures the
communication duration so as to integrate, among the
plurality of communication processes, a communication
process in which the first communication processing is
incapable of being performed to a particular communication
process.
[Claim 5] The relay station according to claim 4, further
comprising a first measurement duration management unit to
allocate a measurement period for measuring, by the mobile
station, a radio signal of a frequency different from a
communication frequency between the relay station and the

mobile station to a duration in which the first
communication processing is incapable of being performed
among the plurality of communication processes.
[Claim 6] The relay station according to claim 4 or 5,
wherein at least a part of the configured uplink
communication duration is allocated to uplink data
transmission that needs no acknowledgment from the base
station.
[Claim 7] A mobile station to perform radio communication
with a base station through a relay station, the mobile
station comprising:
a transmission and reception unit to transmit and
receive a radio signal to and from the relay station; and
a second communication management unit to manage
communication timing between the mobile station and the
relay station based on at least one of a downlink
communication duration in which the relay station receives
a transmission signal from the base station while limiting
transmission of a signal from the relay station to the
mobile station and an uplink communication duration in
which the relay station transmits a transmission signal to
the base station while limiting transmission of a signal
from the mobile station to the relay station,
wherein the communication duration is configured
in such a manner that a communication process in which,

among the plurality of communication processes, the first
communication processing is incapable of being performed is
integrated into a particular communication process.
[Claim 8] The mobile station according to claim 7,
further comprising a second measurement duration management
unit to allocate a measurement period for measuring a radio
signal of a frequency different from a communication
frequency between the mobile station and the relay station
communicating therewith to a duration in which the first
communication processing is incapable of being performed
among the plurality of communication processes.
[Claim 9] A mobile communication system comprising:
a base station;
a mobile station; and
a relay station to relay radio communication
between the base station and the mobile station;
wherein:
the relay station comprises a control unit which
configures at least one of a downlink communication
duration in which the relay station receives a transmission
signal from the base station while limiting transmission of
a signal from the relay station to the mobile station and
an uplink communication duration in which the relay station
transmits a transmission signal to the base station while
limiting transmission of a signal from the mobile station

to the relay station;
the base station comprises a transmission and
reception unit which transmits and receives a signal
between the base station and the relay station based on the
communication duration;
the mobile station comprises a transmission and
reception unit which transmits and receives a signal
between the mobile station and the relay station based on
the communication duration;
a plurality of communication processes in which
first communication processing including data transmission
and an acknowledgment after a predetermined first time
period from the data transmission is managed are provided
on an access link between the mobile station and the relay
station; and
the communication duration is configured in such a
manner that, among the plurality of communication
processes, a communication process in which the first
communication processing is incapable of being performed is
integrated into a particular communication process.
[Claim 10] The mobile communication system according to
claim 9, wherein a duration in which the first
communication processing is incapable of being performed
among the plurality of communication processes is allocated
to a measurement period for measuring, by the mobile
station, a radio signal of a frequency different from a

communication frequency between the relay station and the
mobile station.
[Claim 11] The mobile communication system according to
claim 9 or 10, wherein at least a part of the configured
uplink communication duration is allocated to uplink data
transmission that needs no acknowledgment from the base
station.

ABSTRACT

A backhaul is configured in such a manner that a
HARQ process in which a HARQ on an upstream access link is
incapable of being partly or entirely performed is limited
to a particular one of a plurality of HARQ processes. As a
result, complexity of scheduling is reduced and efficiency
of the access link is improved.