TITLE OF THE INVENTION
RADIO BASE STATION, RELAY STATION AND RADIO
COMMUNICATION METHOD
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a radio
base station, a relay station, using radio
communication, and a radio communication method.
The present invention is especially advantageous
when it is applied to a case where a radio
communication system prescribed by IEEE802.16 is
used as a base system and thereto a relay station is
added.
2. Description of the Related Art
A radio communication system carrying out
communication with the use of a radio channel, i.e.,
WCDMA, CDMA2000 or such, as a typical example,
currently spreads worldwide. In such a radio
communication system, a plurality of radio base
stations are set for a service area, and each radio
terminal carries out communication with another
communication apparatus (i.e., another communication
terminal) with the use of any of the radio base
stations. At this time, an overlapping area is
provided with an adjacent service area in which an
adjacent base station can carry out radio
communication, and, handover to the adjacent radio
base station is available when a radio environment
degrades.
Further, as a radio communication method,
for example, code division multiplexing, time
division multiplexing, frequency division
multiplexing, OFDMA or such, is applicable. In
these methods, generally speaking, a plurality of
radio terminals can connect to a single radio base

station simultaneously.
However, even within the service area in
which the radio base station can carry out radio
communication, high speed communication may not be
available in a place close to the area boundary,
since the radio environment may not be satisfactory.
Further, even within the area, radio signal
propagation may be obstructed by a cause such as a
building shade. Thus, an area (so-called dead zone)
in which satisfactory radio connection with the
radio base station is difficult may occur.
In order to solve the problem, a plan in
which a relay station is disposed in the service
area of the radio bases station, and radio
communication is available between the radio
terminal and the radio base station with the use of
the relay station, has been proposed.
Especially, in a task group of 802.16j,
introduction of such a relay station (RS) is
currently studied.
As to the above-mentioned IEEE802.16,
details are disclosed in, for example, IEEE Std
802.16TM-2004 and IEEE Std 802.16eTM-2005.
SUMMARY OF THE INVENTION
In the related art described above, the
radio terminal can carry out radio communication
with the base station directionally or with the use
of the relay station. In this case, it is necessary
to determine how the radio terminal utilizes the
relay station.
An object of the present invention is to
provide a system and a procedure for efficiently
utilizing the relay station.
Another object of the present invention is
to prevent management of the radio terminal by the
radio base station from being obstructed by the

existence of the relay station.
Further another object of the present
invention is to prevent degradation in the
transmission efficiency otherwise degrading due to a
fact that a radio communication environment between
the radio base station and the relay station may not
necessarily equal to that between the relay station
and the radio terminal.
Other than these objects, advantages which
may be obtained from respective configurations of
preferred embodiments described later, which are not
obtained from the related art, may be regarded as
further objects of the present invention.
(1) According to the present invention, a
relay station is used, which has:
a reception unit receiving a signal
sequence indicating a connection request, from a
predetermined signal sequence group;
a control unit generating a ranging
request message indicating that a radio terminal
newly requesting connection exists; and
a transmission unit transmitting the
ranging request message to a radio base station.
(2) Further, according to the present
invention, a radio base station is used, which has:
a reception unit receiving a ranging
request message, transmitted from a relay station in
response to reception of a signal sequence
indicating a connection request from a radio
terminal;
a control unit determining in response to
the reception whether or not connection with the
radio terminal is to be newly permitted, and
generating a ranging response message including the
determination result; and
a transmission unit transmitting the
ranging response message to the relay station.

(3) Further, according to the present
invention, a relay station is used, which has:
a reception unit receiving a signal
sequence indicating a connection request, from a
predetermined signal sequence group;
a control unit generating reception
information of the signal sequence received by the
reception unit or correction value information
indicating a deviation from a predetermined
criterion calculated upon the reception of the
reception unit; and
a transmission unit transmitting the
reception information or the correction value
information to a radio base station.
(4) Further, according to the present
invention, a relay station is used, which has:
a reception unit receiving a first ranging
request message including an identifier of a radio
terminal, from the radio terminal;
a control unit generating in response to
the reception a second ranging request message
including the identifier of the radio terminal; and
a transmission unit transmitting the
second ranging request message to a radio base
station.
(5) Preferably, the identifier included in
the second ranging request message may be stored in
a payload or a header.
(6) Further, according to the present
invention, a radio base station is used, which has:
a reception unit receiving from a relay
station a ranging request message;
a control unit storing identification
information of a radio terminal included in the
ranging request message, and generating a ranging
response message corresponding to the ranging
request message; and

a transmission unit transmitting to the
relay station the ranging response message.
(7) Preferably, the control unit may
include in the ranging response message a connection
identifier allocated to the radio terminal; and
the connection identifier is stored with a
correspondence to the identifier of the radio
terminal.
(8) Further, according to the present
invention, a radio communication method is used,
which has the steps of:
in a relay station, receiving a first
ranging request message including an identifier of a
radio terminal, from the radio terminal, generating
a second ranging request message to which the
identifier of the radio terminal is added, and
transmitting the second ranging request message to a
radio base station; and
in the radio base station, receiving the
second ranging request message, storing the
identifier of the radio terminal included in the
second ranging request message, generating a ranging
response message corresponding to the second ranging
request message, and transmitting the ranging
response message to the relay station.
(9) Further, according to the present
invention, a radio communication method is used,
which has the steps of:
in a relay station, receiving a signal
sequence indicating a connection request from a
radio terminal, generating a ranging request message
indicating that the radio terminal newly requesting
connection exits, and transmitting the ranging
request message; and
in a radio base station, receiving the
ranging request message, determining whether or not
to newly permit a connection of the radio terminal,

generating a ranging response message including the
determination result, and transmitting the ranging
response message.
(10) Preferably, the ranging request
message may be transmitted to the radio base station
when the reception of the signal sequence meets a
predetermined criterion, and may not be transmitted
when the predetermined criterion is not met.
(11) Further, according to the present
invention, a radio communication method is used,
which has the steps of:
in a relay station, receiving a signal
sequence indicating a connection request from a
radio terminal; and
in the relay station, determining whether
or not to newly permit connection with the radio
terminal, generating a ranging response message
including the determination result, and transmitting
the ranging response message to the radio terminal.
(12) Further, according to the present
invention, a relay station is used, which has:
a reception unit receiving a signal
sequence indicating a connection request from a
radio terminal;
a control unit determining whether or not
to newly permit connection with the radio station,
and generating a ranging response message including
the determination result; and
a transmission unit transmitting the
ranging response message to the radio terminal.
(13) Further, according to the present
invention, a radio base station is used, which has:
a control unit generating key information
used for communication between a radio terminal and
the radio base station; and
a transmission unit transmitting the key
information to the radio terminal and a relay

station.
(14) Preferably, the key information may
include a shared key and an authentication key.
(15) Preferably, the control unit may
transmit the key information after encrypting it
with such a key that the relay station can decrypt
it.
(16) Further, according to the present
invention, a relay station is used, which has:
a reception unit receiving a message
transmitted from a radio base station;
a processing unit modifying data obtained
from decrypting encrypted data transmitted between a
radio terminal and the radio base station, with key
information included in the message; and
a transmission unit transmitting the thus-
modified data.
(17) Preferably, the key information may
include shared key information, and the data
transmitted by the transmission unit may include
data obtained from encryption with the use of the
shared key information after the modification.
(18) Further according to the present
invention, a relay station is used, which has:
a reception unit receiving a message
transmitted from a radio base station;
a processing unit modifying data to which
authentication data is added, transmitted between a
radio terminal and a radio base station, and adding
the authentication data to the thus-modified data
with the use of authentication key information
included in the message; and
a transmission unit transmitting the data
to which the authentication data is added by the
processing unit.
According to the present invention, it is
possible to provide the system and the procedure in

which the relay station can be efficiently used.
Further, according to the present
invention, management of the radio terminal by the
radio base station can be made smoothly even with
the existence of the relay station.
Further, according to the present
invention, it is possible to prevent degradation in
the transmission efficiency otherwise degrading due
to a fact that a radio communication environment
between the radio base station and the relay station
may not necessarily equal to that between the relay
station and the radio terminal.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and further features of the
present invention will become more apparent from the
following detailed description when read in
conjunction with the accompanying drawings:
FIG. 1 shows an example of a ranging and
basic capability registration sequence;
FIG. 2 shows a processing flow of a RS
when receiving a ranging code from a MS;
FIG. 3 shows a processing flow of a RS
when receiving a ranging request from the MS;
FIG. 4 shows a processing flow of the RS
when receiving a ranging response from the BS;
FIG. 5 shows a processing flow of the BS
when receiving a ranging request;
FIG. 6 shows a block configuration example
of the BS;
FIG. 7 shows a management table of the MS
(1) ;
FIG. 8 shows a block configuration example
of the RS;
FIG. 9 shows another example of the
ranging and basic capability registration sequence;
FIG. 10 shows a processing flow of the RS

when receiving a ranging code from the MS;
FIG. 11 shows a processing flow of the RS
when receiving a ranging request from the MS;
FIG. 12 shows a processing flow of the RS
when receiving a ranging response from the BS;
FIG. 13 shows a processing flow of the BS
when receiving a ranging request;
FIG. 14 shows another block configuration
example of the RS; and
FIG. 15 shows an example of an
authentication sequence.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to figures, embodiments of
the present invention will be described. It is
noted that, although separate embodiments are
described, for the sake of convenience, they may be
combined and thus, with advantages from the
combination, the advantages may be further improved.
[a] Description of first embodiment:
In a first embodiment of the present
invention, a relay station transmits a signal after
processing a signal received from a radio terminal,
to a radio base station.
In this configuration, the relay station
positively functions in communication between the
radio terminal and the radio base station. For
example, a signal which is not necessarily required
to be transmitted to the radio base station is not
transmitted to the radio base station. Thus,
management of the radio terminal by the radio base
station can be carried out smoothly. Further,
signal processing which can be carried out by the
relay station is carried out by the relay station
itself. Accordingly, it is possible to reduce a
processing load of the radio base station. Further,

the radio base station can manage as to which relay
station is used by the radio terminal.
"Basic system configuration":
FIG. 1 shows a processing sequence for a
case where the relay station is newly introduced to
a radio communication system prescribed in
IEEE802.16, as one example of a radio communication
system including the radio base station and the
radio terminal for carrying out radio communication.
This sequence may also be applied to another type of
radio communication system.
First, a basic function of each apparatus
will be described.
In FIG. 1, a BS (Base Station) 300 denotes
a radio base station, which is one of radio base
stations disposed in an area in which the present
radio communication system provides a radio
communication service. Accordingly, there are other
radio base stations providing other radio areas,
which are not shown, adjacent to the area provided
by the present radio base station.
In this radio communication system,
transmission/reception channels (i.e., uplink and
downlink channels) of an MS 100 and an RS 200 are
controlled by transmission/reception channel
definition data, called MAP data.
The MAP data includes, for example,
transmission/reception timing, sub-channel
information used for transmission/reception, code
values indicating a modulation method and an error
correction coding method, and a CID (Connection ID).
The MS 100 and the RS 200 determine whether or not
connection is relevant to themselves, from the CID,
and, carry out radio communication (transmission or
repetition of a radio signal) in the
transmission/reception timing, with the sub-cannels

corresponding to the CID. Accordingly, it may be
said that the MAP data defines a
transmission/reception region. It is noted that,
data of the MAP data, defining the communication
region of the uplink direction (from the MS 100 to
the RS 200 (or the BS 300), is referred to as UL (Up
Link)-MAP data, while data of the MAP data, defining
the communication region of the downlink direction
(from the BS 300 to the RS 200 (or the MS 100)), is
refereed to as DL (Down Link)-MAP data.
The MS 100 denotes a radio terminal, which
exists in the radio area provided by the BS 300, and
thereby, can communicate with the BS 300. It is
noted that the radio terminal is allowed to carry
out communication with changing a location (for
example, upon moving). Then, when it moves to under
another base station providing adjacent another
radio area, handover processing is carried out and
thereby, radio communication can be continued. The
MS 100 can communicate directly with the BS 300.
However, in this example, the MS 100 carries out
radio communication with the BS 300 with the use of
the RS 200.
The RS 200 denotes a relay station, which
is disposed so that it can communicate with the BS
300, transmits a signal to the MS 100 based on a
signal received from the BS 300, or, reversely,
transmits a signal to the BS 300 based on a signal
received from the MS 100, whereby the above-
mentioned dead zone can be eliminated.
"Ranging and basic capability registration":
Next, with reference to FIG. 1, a ranging
and basic capability registration sequence for
starting connection of the radio terminal with the
radio base station will be described. FIG. 1 shows
processing for when so-called network entry is

carried out.
It is noted that both the BS 300 and the
RS 200 generate the MAP data, respectively, and
transmit the same. That is, the BS 300 transmits
the MAP data for defining a transmission/reception
region of radio communication with the MS 100
belonging thereto and with the RS 200 with which
radio communication is directly carried out.
Further, based on the data to transmit/receive, the
BS 300 carries out scheduling, and generates the MAP
data according to the scheduling.
The RS 200 generates the MAP data based on
scheduling for defining a transmission/reception
region of radio communication with the MS 100
belonging thereto, and transmits the same.
The transmission/reception region defined
by the MAP data of the BS 300 and the transmission
/reception region defined by the MAP data of the RS
200 are separated by timing, by frequencies, by
spread codes or such, and thus, have such a
relationship that radio communication can be carried
out without obstruction to one another.
In FIG. 1, (1), the RS 200 transmits a
known signal (i.e., a preamble signal) as a
synchronization signal. Then, subsequent to the
preamble signal, MAP data (including both UL- and
DL-MAP data) is used. Also, user data is
transmitted from the RS 200 in the transmission
region defined by the DL-MAP data, to the MS 100 (2).
The MS 100 receives the preamble signal
thus transmitted by the RS 200, and establishes
synchronization to a radio frame which the RS 200
has transmitted. It is noted that, the MS 100
should not distinguish between the RS 200 and the BS
300. This is because, the processing for detecting
the preamble signal and subsequently carrying out
transmission/reception according to the MAP data may

be the same between the case of radio communication
with BS 300 and the radio communication with the RS
200.
The MS 100 receives MAP data (DL and UL)
based on the preamble (2), detects the transmission
region defined by the MAP data, and receives DCD and
UCD transmitted through the transmission region. It
is noted that the DCD and the UCD are data
broadcasted, and thus, BC which is a broadcast
connection ID is stored in the definition
information of the transmission region in the DL-MAP
data and in the transmission region. In the figures,
BC, IR, Bms and Brs, provided at a top of each
message, denote the connection IDs used for
transmission. That is, BC, IR, Bms and Brs denote a
broadcast CID, an initial ranging CID, a MS's basic
CID and a RS's basic CID, respectively.
As a function of the DCD (Downlink Channel
Descriptor), it defines a relationship between code
values DIUC (Downlink Internal Usage Code)
indicating a downlink modulation method and an error
correction encoding method(including an encoding
rate), and the downlink modulation method and the
error correction encoding method (including an
encoding rate) themselves. For example, DIUC=3 may
define 16QAM, a convolution code and an encoding
rate of 3/4. Thereby, merely by defining DIUC=3 in
the DL-MAP, it is possible to notify the RS 200 or
the MS 100 that the region is encoded and modulated
by 16QAM, the convolution code and the encoding rate
of 3/4. Similarly, UCD (Uplink Channel Descriptor)
defines a relationship between code values UIUC
(Uplink Internal Usage Code) indicating an uplink
modulation method and an error correction encoding
method (including encoding rate), and the uplink
modulation method and the error correction encoding
method (including encoding rate) themselves.

Thus, by receiving the definitions of DIUC
and UIUC from DCD and UCD, it becomes possible that
the MS 100 or RS 200 can interpret the DL-MAP or UL-
MAP. The MS 100 obtains the transmission region by
which transmission of a ranging code indicating a
request for connection of the MS 100 is allowed, by
receiving the UL-MAP data in (2) or by receiving the
UL-MAP data included in the subsequent frame (3).
The ranging region is a region for transmitting a
predetermined signal (i.e., a CDMA ranging code)
from the MS 100. The RS 200 notifies of this region
to the MS 100 with the MAP data. The ranging region
may be one including a plurality of regions, for
example, and thus, such a manner is allowed that a
first MS transmits a predetermined signal in a first
region while a second MS transmits a predetermined
signal in a second region.
As the CDMA ranging code (i.e., a signal
sequence), for example, it is preferable to
selectively use, from a predetermined number or
plurality of codes (i.e., a signal sequence group).
For example, upon transmission of a code, the MS 100
selects one of the plurality of codes, and transmits
the same. Upon the selection, it is possible to
reduce a possibility that the same code is selected,
even when a plurality of MSs share the codes, when
the code is selected randomly.
After obtaining the transmission region
for the ranging signal, the MS 100 selects any of
the regions (for example, a first region) from among
the ranging regions, and transmits the selected CDMA
code (for example, a code 1) in the selected region
(4) .
The CDMA ranging code is a CDMA code for
initial ranging. On the other hand, when the MS 100
comes from another BS 300 in a handover manner, a
CDMA code for HO ranging is transmitted.

The RS 200 receives the CDMA ranging code
transmitted in the transmission region of the
ranging signal, and stores the code reception
information such as the reception timing (for
example, which region is used), a type of the code
(in this example, the code 1, mentioned above) and
so forth. Further, other than the code reception
information, a deviation of the frequency (sub-band)
upon the code reception from a standard frequency, a
deviation of the reception power from a standard
reception power, a deviation of the reception timing
from standard timing (i.e., the transmission region
of the ranging region defined by the MAP data) and
so forth are measured, and are stored as correction
values (i.e., correction values of transmission
parameters of the MS 100).
Then the RS 200 transmits an RNG-REQ
message to the BS 300 (5).
As transmission timing of the RNG-REQ
message, a region in which data transmission is
possible from the RS 200 to the BS 300, defined by
the UL-MAP transmitted by the BS 300, is used. That
is, a communication link (MMR link) using the data
transmission/reception region between the BS 300 and
the RS 200, defined by the BS 300, is used. However,
in this case, the MMR link in the uplink direction
is used. Further, as to the MMR link, different
regions should be preferably designated to
respective RSs, for the purpose of avoiding
collision.
As the contents of the RNG-REQ message, a
message requesting ranging may be used.
Specifically, a basic CID of the RS 200 as a
connection ID (for example, a CID, designated by the
BS 300, which is an ID for distinguishing from the
radio terminal and the other relay stations
belonging to the BS 300, i.e., Brs) may be used, and

the message may include data (i.e., New MS) for
notifying that entry of a new MS 100 is made (i.e.,
a new MS 100 exists which requests connection).
It is preferable that the above-mentioned
New MS is data (i.e., the number) which is changed
(incremented) each time the RNG-REQ message
including New MS is transmitted. For example, when
the RS 200 receives the code 1 in the first region
of the ranging region, subsequently receives a code
2 in the second region, and transmits RNG-REQ
messages for the respective codes, the transmission
may be made with such a setting of SN=1, and then,
SN=2, respectively.
The example of the contents of the message
transmitted in (5) has been thus described.
Preferably, this message may be transmitted to the
BS 300 when the deviations of the frequency, the
reception power level and the timing upon the code
reception lie within predetermined ranges (i.e., no
correction is required; a "success" status).
Otherwise, the message may not be transmitted to the
BS 300. This is because, when the error is large,
the MS 100 should be made to again transmit the CDMA
code, then the RNG-REQ message should be generated
based on the re-transmitted CDMA code, and, should
be transmitted to the BS 300. Thus, it is possible
to reduce messages to be transmitted to the BS 300,
and thus, the processing load of the BS 300 can be
reduced.
The BS 300 receiving the RNG-REQ can
determine from the CID the relay station which has
thus transmitted the message. Then, since the
message indicates that the entry of the new MS 100
is made, the BS 300 refers to the communication
resources of the BS 300 itself (i.e., radio channels,
radio communication units and so forth), RS busy
resource conditions and so forth, which are

separately managed and stored, and, determines
whether or not the new MS 100 can be accepted.
The determination result is then
transmitted to the RS 200 as a RNG-RSP message (6).
The transmission region to be used there is the MMR
link defined by the MAP data of the BS 300 described
above. As the CID, Brs can be used.
In this RNG-RSP message, for example, a
"success" status may be included when the MS 100 can
be accepted, while an "abort" status may be included
when the MS 100 cannot be accepted. If necessary,
the New MS, the same as the New MS in the RNG-REQ
received from the RS, may be further included.
The RS 200 has having received the RNG-RSP
message from the BS 300 continues the ranging
processing of the MS 100 when the status thus
notified of is "success". That is, when a
correction is required for the reception frequency,
the reception power level and the reception timing
of the ranging code which the RS 200 has received,
the RS 200 transmits RNG-RSP ("continue" status) as
a response message including the corresponding
correction values.
The correction values are those obtained
upon the reception of the ranging CDMA code, which
is stored in the above-mentioned example. In order
to search for the correction values, the New MS may
be used as a search key when the correction values
are stored with correspondence to the New MS. Any
other identification information may also be used as
a search key.
When no correction is required, the RS 200
transmits RNG-RSP ("success") as a response message
(7) .
On the other hand, when the status
notified of from the BS 300 is "abort", the RS 200
transmits to the MS 100, RNG-RSP of an "abort"

status. The MS 100 which has thus received the RNG-
RSP of the "abort" status stops the connection
processing for the RS 200, and then, inquires into
another BS or another RS. That is, the MS 100 tries
to receive another preamble.
It is noted that, in such a case that the
BS's resources are sufficient, the RS 200 may omit
the step of transmitting the RNG-REQ to the BS 300
notifying existence of the MS 100 which requests
connection, in response to the reception of the
ranging code. That is, the transmission/reception
with the BS 300 in (5), (6) may be omitted, and RNG-
RSP ("continue" status) or RNG-RSP ("success"
status) may be transmitted in (7). Thereby, an
increase in the processing speed can be achieved.
The BS 300 may notify the RS 200 of the number of
MSs which can be processed through the MMR link, and
the RS 200 may omit the processing as mentioned
above, when this number is not actually exceeded.
It is noted that the RNG-RSP message is
transmitted in the transmission region which is made
to have correspondence to IR (Initial Ranging) as a
connection ID in the DL-MAP data. The IR may be
used as one unique ID used for ranging processing.
At this time, since RNG-RSP can be received by all
the radio terminals which have transmitted the CDMA
ranging code, it is preferable that the reception
information of the CDMA ranging code is stored in
the RGN-RSP message, and thus the transmission
destination of the RNG-RSP is specified. It is
noted that, in the examples mentioned below, the RS
200 stores the reception information of the CDMA
ranging code, search may be made with the New MS or
such which may be used as a key, and, the thus-
obtained reception information may be transmitted.
The MS 100 having received the RNG-RSP
adjusts the frequency, transmission power and timing

according to the correction values included in the
RNG-RSP when the status is "continue", and again,
the MS 100 transmits a ranging CDMA code to the RS
200 (not shown). When the status is "success", the
MS 100 receives the CDMA allocation IE included in
the UL-MAP data included in the same frame or a
subsequent frame.
As the CDMA allocation IE included in the
UL-MAP data, BC is used as a connection ID.
Therefore, all the radio terminals belonging to the
RS 200 can receive it. Accordingly, the MS 100
carries out matching the type of the code (code 1)
and the timing (region 1) which the MS 100 itself
has transmitted, with the reception information of
the code stored in the CDMA allocation IE. Then,
when the matching results in agreement, the MS 100
receives it as a message transmitted for itself, and
detects the transmission region defined by the CDMA
allocation IE. On the side of RS 200, a
correspondence relationship between the transmission
region which the RS 200 has allocated and the
identification information of the MS 100 such as New
MS or such, is stored.
The MS 100 who thus has received the CDMA
allocation IE transmitted for itself, transmits an
RNG-RSP message including the MAC address (MSID)
which is identification information for the MS 100,
to the RS 200 via the transmission region detected
as mentioned above (9). It is noted that, as a
connection ID, the IR is used, which is also stored
in the RNG-RSP message.
When receiving the RNG-RSP message
designated by the CDMA allocation IE via the
transmission region, the RS 200 specifies the New MS
corresponding to the transmission region, and,
generates and transmits an RNG-REQ message to the BS
300.

In this stage, the identification
information (MSID) of the MS 100 has been obtained.
Accordingly, as a result of the MSID being included
in the RNG-REQ message, it can be seen that the RNG-
REQ message transmitted by the RS 200 corresponds to
a ranging request from the MS 100. Preferably, the
New MS should be further included there.
The RS 200 adds Brs which is the basic CID
of the RS 200 to the information to obtain the RNG-
REQ message, and transmits the same to the BS 300
via the MMR link (10).
When receiving the RNG-REQ message from
the RS 200, the BS 300 identifies the RS 200 which
has transmitted the message, from the CID (Brs)
included in the header thereof. Further, the BS 300
stores the MAC address of the MS 100 (MSID) included
in the payload part, with association to the RS 200.
Thereby, the BS 300 can manage as to which RS the MS
300, identified by the MSID, belongs to. From the
New MS included in the RNG-RSP, it is possible to
check whether or not the MS, the same as the MS for
which the status "success" has been given in (5),
(6), has transmitted the RNG-REQ. When the New MS
does not correspond to the MS 100, from which the
message has been received (5), the subsequent
processing may be rejected and the current
processing may be terminated.
The BS 300 having received the RNG-RSP
message further creates a basic CID and a primary
CID for the MS 100, adds the MSID, and thus,
generates an RNG-RSP message, which is then returned
to the RS 200. At this time, as a connection ID,
Brs may be used. Then, with the use of the MMR link,
the same as the above, the RNG-RSP message is
transmitted via the data region (11).
The RS 200 which has thus received the
RNG-RSP message including the basic CID and the

primary CID for the MS 100, from the BS 300,
converts the connection ID in the header into IR,
and transfers the RNG-RSP message, having been thus
converted, to the MS 100 (12). It is noted that the
connection ID is stored in the DL-MAP data together
with the definition information of the corresponding
data transmission region, and also, it is stored in
the header part of the data stored in the
transmission region.
Based on IR which is the connection ID of
the DL-MAP data, the MS 100 receives the
corresponding data transmission region, and then,
the MS 100 receives the RNG-RSP message including
the basic CID and the primary CID. Since the MSID
is also stored, the MS 100 can easily determine that
the message is one for itself.
After that, the MS 100 carries out
processing for notifying of a capability of itself.
That is, with the use of the thus-obtained
basic CID as the connection ID, the MS 100 transmits
an SBC-REQ message to the RS 200. That is, the SBC-
REQ message (including the basic CID) is transmitted
via the transmission region designated as a region
for transmission by the UL-MAP data (13).
The RS 200 having received the SBC-REQ
message transfers the same with the basic CID of the
MS 100 used as it is, to the BS 300 via the MMR link
(14) .
The BS 300 having received the SBC-REQ
message generates an SBC-RSP message notifying the
MS 100 of a function, from among those of the
capability of the MS 100, thus notified of from the
MS 100, which each of the MS 100, RS 200 and BS 300
can support. The SBC-RSP message is then
transmitted to the RS 200 via the MMR link (15). At
this time, the basic CID of the MS 100 is used as
the connection ID. It is noted that, the contents

which are thus notified of, are stored with
correspondence to the MS 100, on the side of the BS
300.
Brs may also be used as the connection ID
for the MMR link. In this case, it is preferable
that information for identifying the MS 100 is
stored in the message. As the information to store,
for example, MSID, the basic CID of the MS 100 or
such, may be used. From the information, the BS 300
can identify the MS 100, and thus, can identify the
MS for which the capacity to use is determined. As
another method, it is also possible to carry out
transmission/reception ((14), (15)) of the messages
using the MMR link with the use of another CID
corresponding, in a one-to-one manner, to the basic
CID of the MS 100.
The RS 200 transfers the SBC-RSP to the MS
100 (16). The basic CID may be used as the
connection ID.
Thus, the ranging and basic capability
registration sequence has been described. Thereby,
the reception information of the code should not be
transmitted to the BS 300. Thus, it is possible to
prevent degradation in the channel efficiency.
Further, management of the MS 100 by the BS 300 can
be carried out easily.
It is noted that, in the process of
relaying the messages between the MS 100 and the BS
300, the RS 200 may obtain the information included
in the messages and store the same.
Thereby, not only the BS 300 but also the
RS 200 can manage the MAC address (MSID) of the MS
100, the basic CID, the primary CID, and the support
functions notified by the SBC-REQ and SBC-RSP
messages.
Thereby, the RS 200 can properly select
the modulation method and the error correction

encoding method supported by the MS. Also, the RS
200 may transmit the stored contents in response to
a query from the BS 300. Thus, the RS 200 can
function as a backup apparatus.
"Processing flow in RS, BS":
Next, processing flows in each apparatus
will be described.
FIG. 2 shows a processing flow of the RS
200 upon receiving the ranging code from the MS 100;
FIG. 3 shows a processing flow of the RS 200 when
receiving the RNG-REQ from the MS 100; FIG. 4 shows
a processing flow of the RS 200 when receiving the
RNG-RSP from the BS 300; and FIG. 5 shows a
processing flow of the BS 300 when receiving the
RNG-REQ.
Processing flow of the RS 200 when receiving the
ranging code from the MS 100 (FIG. 2):
This processing flow is carried out by a
control part of the RS 200.
The RS 200 determines whether or not to
have received the ranging code from the MS 100 (SI).
When the determination result is No, the RS 200
carries out subsequent reception again (SI). When
the result is Yes, the RS 200 determines the status
of code reception (S2). When the status is "success"
(Yes), the RS 200 generates an RNG-REQ message
including information "New MS" indicating that a new
MS connection request exists (S3), and transmits the
same to the BS 300 with the basic CID of the RS 200
added in the CID field of the header (S4).
When the result of S2 is No (not
"success"), the RS 200 transmits an RNG-RSP message
to the MS 100, including a status "continue" (S5).
At this time, initial ranging (IR) is used as the
CID.

Processing flow of the RS 200 when receiving the
RNG-REQ from the MS 100 (FIG. 3):
This processing flow is mainly carried out
by the control part of the RS 200.
The RS 200 determines whether or not to
have received the RNG-REQ from the MS 100 (Sll) .
When the result is No, next reception check is
carried out (Sll). When the result is Yes, it is
determined whether or not the CID is IR (S12) . When
the result is No, periodic ranging processing of the
MS 100 is carried out (S15). That is, instead of
initial ranging being carried out first, a signal
for correcting errors in the transmission power, the
transmission timing, the transmission frequency and
so forth, is generated, as ranging processing which
should be carried out periodically after that, and
the signal is transmitted to the MS 100.
When the result of S12 is Yes, the RS 200
converts the CID of the header of the received RNG-
REQ message into the basic CID of the RS 200, and
transmits the RNG-REQ message to the BS 300 (S13,
S14). New MS may also be included in the message.
Processing flow of the RS 200 when receiving the
RNG-RSP from the BS 300 (FIG. 4):
This processing flow is mainly carried out
by the control part of the RS 200.
First, the RS 200 determines whether or
not to have received the RNG-RSP (S21). When the
result is No, next reception check is carried out
again (S21). When the result is Yes, the RS 200
determines whether or not the CID is other than the
IR (S22). When the result is the IR (No), the RS
200 carried out initial ranging processing of the RS
200 (S26).
When the result of S22 is Yes (for example,

the CID is Brs), it is determined whether or not a
"New MS" flag exists (S23). When the result is No,
it is determined whether or not MSID exists (S25).
When MSID exists (Yes), the CID of the header of the
RNG-RSP is changed into the IR, and the RNG-RSP is
transmitted to the MS 100 (S29). When MSID does not
exist (No in S25), the RS 200 adjusts the frequency,
transmission power and timing according to the
correction information included in the RNG-RSP, as
periodic ranging processing of the RS 200 itself
(S30) .
On the other hand, when the "New MS" flag
exists (Yes in S23), it is determined whether or not
the status is "success" (S24). When the status is
"success" (Yes), the RNG-RSP including the status
"success" is returned to the MS 100 (S28). When the
status is other than "success" (No in S24), the RNG-
RSP including of a status "abort" is returned to the
MS 100 (S27) .
Processing flow of the BS 300 when receiving the
RNG-REQ (FIG. 5):
This processing flow is carried out mainly
by a control part of the BS 300.
First, the BS 300 determines whether or
not to have received the RNG-REQ (S41). When the
result is No, the BS 300 carries out next reception
check again (S41). When the result of S41 is Yes,
it is determined whether or not the CID is other
than the IR (S42). When the result is No (i.e., the
CID is the IR), the BS 300 carries out initial
ranging processing of the MS 100 or the RS 200 which
the BS 300 communicates with directly (S52).
When the CID is other than the IR (Yes in
S42), it is determined whether or not the CID is the
basic CID of the RS 200 (S43). When the result is
No, the BS 300 carries out periodic ranging

processing of the MS 100 (S48) .
When the CID is the basic CID of the RS
200 (Yes in S43), it is determined whether or not a
"New MS" flag exits (S44). When the "New MS" flag
exists (Yes), it is determined whether or not the
new MS 100 can be accepted (S46). When it can be
accepted (Yes), the BS 300 generates an RNG-RSP
including a status "success", and transmits the RNG-
RSP to the RS 200 with the use of the same CID as
that of the RNG-REQ (S50). When the new MS 100
cannot be accepted (No in S46), the BS 300 generates
an RNG-RSP including a status "abort", and transmits
the RNG-RSP to the RS 200 with the use of the same
CID as that of the RNG-REQ (S51).
When no "New MS" flag exists (No in S44),
the BS 300 determines whether or not the MS MAC
address (MSID) exists (S41). When MSID does not
exist (No), the BS 300 carries out periodic ranging
processing of the RS 200. When MSID exists (Yes in
S41), the BS 300 stores the MAC adders (MSID)
included in the RNG-REQ, with association to the RS
200 expressed by the CID included in the header of
the message (S47). Then, the BS 300 generates an
RNG-RSP including the basic CID and the primary CID,
and transmits the same to the RS 200 with the use of
the same CID as that of RNG-REQ (S49) .
"Configuration of each apparatus":
FIG. 6 shows a block configuration of the
BS 300.
In FIG. 6, 10 denotes an antenna for
transmission/reception of radio signals with the RS
200 or the MS 100; 11 denotes duplexer for the
antenna 10 to be shared for transmission/reception;
12 denotes a reception part; 13 denotes a
demodulation part for demodulating the reception
signal; 14 denotes a decoding part for decoding the

demodulated reception signal; 15 denotes a control
message extraction part extracting control data from
the reception signal to give it to a ranging control
part 26, and also, transferring data such as user
data to a packet reproduction part 16; 16 denotes
the packet reproduction part generating a packet
from the data transferred from the control message
extraction part 15 to give it to a NW interface part
17.
17 denotes the NW interface part for
providing an interface (in this example, for packet
communication) with a routing apparatus (not shown;
which is connected to a plurality of radio base
stations, and carries out data forwarding control);
18 denotes a packet identification part, which
identifies an IP address included in packet data
received through the NW interface part 17,
identifies a destination MS 100 based on the IP
address (for example, a correspondence between IP
address data and the MS's ID being previously stored,
and, ID of the corresponding MS being obtained), and
also, obtains QoS information corresponding to the
ID (QoS being also previously stored with
correspondence to the ID), gives the QoS information
to an MAP information generation part 21 to request
it to allocate a band, and stores the packet data
received from the NW interface part 17 in a packet
buffer part 19.
21 denotes the MAP information generating
part which, in response to the band allocation
request, determines a communication route by
searching with the MS's ID as a key (or determines a
relay station to use), generates MAP data setting a
mapping area according to the QoS in any of the
downlink data transmission regions, and also, gives
instructions to a PDU generation part 20 for
configuring a radio frame according thereto.

20 denotes the PDU generation part which
generates a PDU such that MAP data and transmission
data are stored in respective regions of a radio
frame created based on a synchronization signal
(preamble), and gives it to an encoding part 22. 22
denotes the encoding part; 23 denotes a modulation
part; and 24 denotes a transmission part. The
encoding part 22 carries out encoding processing
such as error correction enclosing or such on the
PDU data, the modulation part 23 modulates the thus-
obtained data, and the transmission part 24
transmits the thus-modulated data as a radio signal
via the antenna 10.
25 and 26 denote a control message
generation part and the ranging control part,
respectively, included in the control part of the BS
300 which carries out control of the respective
parts of the BS 300.
The control part is connected with a
storage part, in which various sorts of data the BS
300 should store is stored. For example, capability
information determined for each MS, information as
to whether or not MS should be directly communicated
with, and further, information as to which RS is
used to communicate with MS, and so forth, is stored.
Further, the storage part is used for managing busy
conditions of the BS and RS resources.
The control message generation part 25
generates various sorts of control messages
according to instructions from the ranging control
part 26, and gives them to the PDU generation part
20 as transmission data. Further, for the purpose
of ensuring transmission regions, a request for
ensuring the transmission regions is made to the MAP
information generation part 21. At this time, also
information required for creating the MAP data (i.e.,
connection IDs and so forth) is given to the MAP

information generation part 21.
26 denotes the ranging control part, which
analyses the control message (for example, RNG-REQ)
extracted by the control message extraction part 15,
analyses the CID included in the message header, and
requests the control message generation part 25 to
generate RNG-RSP and transmit the same.
When the CID is one for initial ranging
(IR), this means a ranging request message from the
MS or RS belonging to the BS 300. When correction
of the frequency, transmission power and timing of
MS is not required, it is notified to the control
message generation part 25 to generate an RNG-RSP
including the MAC address included in the RNG-REQ,
the "success" status, the basic CID, the primary CID
and so forth, is generated, and transmit it with
CID=IR.
On the other hand, when the above-
mentioned correction is required, it is notified to
the control message generation part 25 to generate
an RNG-RSP including the MAC address included in the
RNG-REQ, the "continue" status and necessary
correction information, and transmit the same with
CID=IR.
When the CID is not for IR, but is the
basic CID of the MS, periodic ranging of the MS is
carried out. The same as the above-mentioned case
of the IR, it is notified to the control message
generation part 25 to generate an RNG-RSP including
contents according to whether or not the correction
is required, and transmit the same with the use of
the basic CID of the RNG-REQ.
When the CID is not for IR but is the
basic CID of the RS, processing to carry out differs
according to whether or not a "New MS" indicator
exists in the payload part of the RNG-REQ message.
When the "New MS" indicator does not exist,

processing to carry out defers according to whether
or not the MS MAC address (MSID) exists. When the
MS MAC address (MSID) does not exist, periodic
ranging processing of the RS is carried out. On the
other hand, when the MS MAC address is included,
this massage that, the received RNG-REQ is one
transmitted from the MS, and then, is relayed by RS.
At this time, the MS MAC address included in the
RNG-REQ and the RS's basic CID included in the
header of the RNG-REQ are managed with association
to one another, so that the RS via which the MS is
connected can be identified. Next, it is notified
to the control message generation part 25 to
generate an RNG-RSP message including the basic CID
and the primary CID to be allocated to the MS, and
transmit it to the RS with the use of the basic CID
of the RS. An MS management table is used to manage
association between the MS and the RS, and the MS's
basic CID and the primary CID.
FIG. 7 shows an example of the MS
management table.
This shows a part of the contents of the
above-mentioned storage part.
As shown in FIG. 7, the MS management
table manages and stores information indicating
whether or not communication via the RS is carried
out with correspondence to the MS's MAC address
(MSID), information indicating which RS is used when
the RS is used, the basic CID and the primary CID.
When the "New MS" indicator exists, it is
determined whether or not the new MS can be accepted.
Whether or not the new MS can be accepted can be
determined from busy conditions of various sorts of
resources, such as the radio resource busy condition,
the management table busy condition, and so forth.
When the new MS can be accepted, it is notified to
the control message generation part 25 to generate

an RNG-RSP including a "success" status, and
transmit it to the RS with the use of the same CID
as that of the RNG-REQ. On the other hand, when the
new MS cannot be accepted, it is notified to the
control message generation part 25 to generate an
RNG-RSP including an "abort" status, and transmit it
to the RS with the use of the same CID as that of
the RNG-REQ.
FIG. 8 shows a block configuration of the
RS 200.
In FIG. 8, 30 denotes an antenna for
transmission/reception of radio signals with the BS
or the MS; 31 denotes a duplexer for the antenna 10
to be shared for the transmission/reception; 32
denotes a reception part; 33 denotes a demodulation
part demodulating a reception signal; 34 denotes a
decoding part decoding the thus-demodulated signal;
and 35 denotes a control message extraction part
which extracts MAP data from the decoded data
(received from the BS), gives it to a MAP
information generation and analysis part 36, and
also, transfers data for the MS from the BS to a
packet buffer part 38. Also the same in a case of
receiving a radio signal from the MS, reception data
is transferred to the packet buffer part 38 for
being transmitted to the BS. Further, the control
message extraction part 35 extracts a control
message (RNG-REQ, RNG-RSP, or such) from the
received message, and gives it to a ranging control
part 39.
37 denotes a code reception part which,
when receiving a ranging code from the MS (initial
ranging, handover ranging or such), determines
whether or not correction is required for the
frequency, reception power level and timing of the
reception signal, and notifies the ranging control
part 39 of the status (success/abort/continue), as

well as information concerning the received code,
for example, code reception information such as the
frame number, sub-channel, code value and so forth
of the reception of the code, together with the
correction values.
39, 40 denote the ranging control part and
a control message generation part included in the
control part controlling the respective parts of the
RS 200, respectively.
The control part is connected to a storage
part. In the storage part, various sorts of data
which the RS 200 should store are stored. For
example, the code reception information, correction
information and so forth are stored.
When receiving information from the code
reception part 37, and when the status is "success",
the ranging control part 39 notifies the control
message generation part 40 to generate an RNG-REQ
including a "New MS" indicator, and transmit it to
the BS with the basic CID of the RS. On one hand,
when the status is "continue", it is notified to the
control message generation part 40 to generate an
RNG-RSP message including the correction information
and information concerning the code, and transmit it
to the MS with the CID for initial ranging.
Further, when the RNG-REQ message is
received from the control message extraction part 35,
the ranging control part 39 determines whether or
not the CID included in the header of the message is
the CID for initial ranging. When it is the CID for
IR, it is notified to the control message generation
part 40 to change the CID field of the header of the
received RNG-RSP message into the basic CID of the
RS 200, and transmit it to BS. On one hand, when it
is not the CID for IR, that is, it is the MS's basic
CID, ordinary periodic ranging processing of the MS
is then carried out.

Further, when the RNG-RSP message is
received from the control message extraction part 35,
first it is determined whether or not the CID is the
CID for initial ranging. When it is the CID for IR,
initial ranging processing of the RS 200 is carried
out. That is, when the MAC address included in the
RNG-RSP is the own MAC address, the basic CID and
the primary CID included in the message are stored,
which are then used for subsequent
transmission/reception of control messages. On the
other hand, when it is other than the CID for IR,
processing to carry out differs according to whether
or not the message includes a "New MS" indicator.
When the "New MS" indicator is included, and also,
when a "success" status is included in the message,
it is notified to the control message generation
part 40 to generate an RNG-RSP message including a
"success" status, and return it to the MS with a CID
for IR. However, when no "success" status is
included, it is notified to the control message
generation part 40 to generate an RNG-RSP message
including an "abort" status, and return it to the MS
with a CID for IR. On one hand, when no "New MS"
indicator is included, and when MSID, i.e., the MS
MAC address is included in the message, it is
notified to the control message generation part 40
to convert the CID field of the header of the
received RNG-RSP message into a CID for IR, and
return it to the MS.
The control message generation part 40
responds to instructions from the ranging control
part 39, to generate the various sorts of control
messages, and give them to the PDU generation part
41 as transmission data. Further, for the purpose
of ensuring transmission regions, a request is made
to the MAP information generation and analysis part
36 for ensuring the transmission regions. At this

time, information required for creating MAP data (a
connection ID and so forth) is also given to the MAP
information generation and analysis part 36.
The MAP information generation and
analysis part 36 uses a broadcast CID transferred
from the control message extraction part 35, to
control downlink and uplink communication (MMR link)
with the BS, according to DL-MAP and UL-MAP obtained
from the BS, and also, to generate DL-MAP and UL-MAP
according to scheduling which is carried by itself,
and transmit them to the MS with the broadcast CID.
In a frame by which the RS 200 transmits the MAP
data and corresponding data, a preamble is included
the same as in the BS 300. This is because
synchronization should be established in the MS.
38 denotes the packet buffer part.
Therewith, according to the MAP data generated by
the MAP information generation and analysis part 36,
packet data is transferred to the PDU generation
part 41 for radio communication.
41 denotes the PDU generation part, which
obtains the MAP data generated by the MAP
information generation and analysis part 36 and data
to be transmitted in the region defined by the MAP
data from the packet buffer part 38 and the control
message generation part 40, and gives them to an
encoding part 41 as the entire transmission data.
42 denotes the encoding part, and 43
denotes a modulation part. The transmission data
given by the PDU generation part 41 is encoded by
the encoding part 42, and modulation processing is
carried out by the modulation part 43 such that,
user data is transmitted in transmission timing and
channel generated by the MAP information generation
and analysis part 36. After that, the thus-obtained
data is given to a transmission part 44.
44 denotes the transmission part which

transmits the given data as a radio signal to the MS
or the BS.
[b] Description of second embodiment:
In the first embodiment described above,
the RS 200 itself generates the MAP data, and
transmits it to the MS 100. However, in a second
embodiment of the present invention, which will now
be described, the BS 300 generates the MAP data
which the RS 200 transmits to the MS 100, and
transmits it via the MMR link. Thus, the RS 200
transmits the MAP data, having been received from
the BS 300, as MAP data which the RS 200 itself is
to transmit.
Thereby, the RS 200 can leave scheduling
processing in the charge of the BS 300, and thus, a
processing load of the RS 200 can be reduced,
whereby the apparatus of the RS 200 can be
miniaturized.
FIG. 9 shows a ranging and basic
capability registration sequence for the MS 100 to
start connection with the RS 200.
In comparison with FIG. 1, it is seen that,
the MAP data (3), (5) and (11), corresponding to the
messages (2), (3) and (8) of FIG. 1, are transmitted
based on the MAP data (2), (4) and (10) (received in
the data regions) given via the MMR link from the BS
300 to the RS 200.
That is, in FIG. 9, a message of (2) is
transmitted as (3), a message of (4) is transmitted
as (5) and a message of (10) is transmitted as (11).
The other messages correspond to those described
above for FIG. 1, and the same processing is carried
out therefor.
The operation will be briefly described.
The MS 100 first receives a preamble
signal from the RS 200 (1), and establishes

synchronization. It is noted that, at this time,
the MS 100 does not distinguish between the RS 200
and the BS 300, and thus, recognizes the RS 200 as
the BS 300.
The BS 300 generates MAP information such
as DL-MAP and UL-MAP which the RS 200 transmits to
the MS 100, and the BS 300 transmits it to the RS
200 with the use of the basic CID of the RS 200, via
the MMR link, through transmission with the data
region (2).
The RS 200 which has received the MAP
information then uses a broadcast CID to transmit
the received MAP information to the MS 100 as DL-MAP
and UL-MAP data (3). It is noted that, the contents
of (2) and (3) are basically identical. However,
the connection ID is changed. Further, while the
message (2) is transmitted via the MMR link with the
data transmission region (i.e., the transmission
region defined by the MAP region), the message (3)
is transmitted in the MAP data transmission region
which the RS 200 carries out transmission. Also,
messages (4) and (10) described below, have the same
relationship.
After receiving messages such as the DL-
MAP, UL-MAP, DCD, UCD and so forth, thus receiving
the necessary information, and then receiving the
UL-MAP defining a ranging region (5), the MS 100
uses the ranging region designated by the MAP to
transmit a ranging CDMA code to the RS 200 (6) .
Also at this time, the UL-MAP, having been generated
by the BS 300, is then transmitted and relayed by
the RS 200.
The RS 200 having received the code, then
transmits an RNG-REQ message to the BS 300 (7),
which message includes information indicating that
the MS 100 exists which requests connection (i.e., a
"New MS" indicator), reception information

concerning the CDMA code, for example, a frame
number and a sub-channel of the reception of the
code, a code value, a status and so forth, and also,
correction values for when the transmission
parameters of the MS 100 should be corrected.
At this time, a "success" status is given
when errors in the frequency, reception power level
and timing lie within predetermined values, while a
"continue" status is given when the errors exceed
the predetermined values. Further, the RNG-REQ
message is transmitted with the use of the basic CID
allocated to the RS 200 by the BS 300. Accordingly,
the BS 300 can determine which RS has received the
connection request, from the CID of the message. It
is noted that, in this sequence, the CDMA code for
initial ranging is assumed. However, the same
operation is also carried out in a case where a CDMA
code for HO ranging which is used when the MS 100
carries out handover from another BS is received.
The BS 300 having received the RNG-REQ
refers to storage data of the storage part for
vacant resources of its own or vacant resources of
the RS 200, and therefrom, determines whether or not
the new MS 100 can be accepted. Then the
determination result is returned to the RS 200 by
means of an RNG-RSP message (8). In this message,
when the new MS 100 is acceptable, in addition to
the "New MS" indicator, the "continue" status, the
CDMA code reception information and the correction
information are included when the status in the RNG-
REQ message received form the RS 200 is the
"continue" status. On the other hand, the "success"
status and the CDMA code reception information are
included when the status in the RNG-REQ message
received from the RS 200 is the "success" status.
The RNG-RSP message is then transmitted to the RS
200 with the use of the basic CID of the RS 200. On

one hand, when the new MS 100 cannot be accepted, an
RNG-RSP message including an "abort" status and the
CDMA code reception information is generated and
transmitted to the RS 200 with the use of the basic
CID of the RS 200.
The RS 200 which has received the RNG-RSP
from the BS 300 generates an RNG-RSP in which, the
"New MS" indicator is removed when the received
message includes the "New MS" indicator, and
transmits the generated message to the MS 100 with
the use of a CID for initial ranging (9).
When transmitting the RNG-RSP of the
"success" status to the RS 200, the BS 300 generates
UL-MAP including CDMA_Allocation-IE to allocate a
band for the MS 100, to transmit an RNG-REQ message
by means of the MAP information generation part 21,
and transmits it to the RS 200 with the use of the
basic CID of the RS 200 via the MMR link (10).
The RS 200 which has received the UL-MAP
including the CDMA_Allocation-IE transmits the
message to the MS 100 with the use of a broadcast
CID (11).
The MS 100 having received the RNG-RSP
adjusts the frequency, reception power level and
timing according to the correction information
included in the RNG-RSP, when the status is
"continue", and again transmits a ranging CDMA code
to the RS 200 (not shown). When the status is
"success", the MS 100 refers to the CDMA_Allocation-
IE included in the UL-MAP massage, and transmits an
RNG-REQ message to the RS 200, which includes the
MAC address of the MS 100 (MSID) (12).
The RS 200 having received the RNG-REQ
from the MS 100 replaces the CID for IR included in
the header of the message transmitted by the MS 100
with the basic CID of the RS 200, and transfers it
to the BS 300 (13).

When receiving the RNG-REQ message
transferred from the MS 100, the BS 300 identifies
the RS 200 which has transmitted the message, from
the CID (the basic CID of the RS 200) included in
the header of the message, and registers it with
association to the MAC address of the MS 100
included in the payload part and the RS 200.
Thereby, it is possible to manage as to which RS the
MS 100 identified from the MAC address belongs to.
Then, the BS 300 generates an RNG-RSP including the
basic CID and the primary CID which are the control
connection for the MS 100 which has transmitted the
RNG-REQ message, and returns it to the RS 200 (14) .
The RS 200 having received the RNG-RSP
including the basic CID and the primary CID for the
MS 100, from the BS 300, changes the CID in the
header of this message into a CID for initial
ranging, and transfers it to the MS 100 (15).
The MS 100 having received the RNG-RSP
including the basic CID and the primary CID
transmits an SBC-REQ message to the RS 200 for
notifying of a capability of the MS 100 itself (16).
The RS 200 having received the SBC-REQ
message from the MS 100 transfers it to the BS 300
(17) .
The BS 300 having received the SBC-REQ
message from the RS 200 generates an SBC-RSP massage
notifying the MS 100 of a function which each of the
MS 100, the RS 200 and the BS 300 can support, from
among the support functions of the capability having
been notified of from the MS 100, and transmits it
to the RS 200 (18). At this time, in order that the
RS 200 can recognize what has the support function
included in the SBC-RSP, the basic CID of the MS 100
included in the header of the SBC-REQ message is
used as it is, and the BS 300 transmits the SBC-RSP
to the RS 200. As another method, the basic CID of

the RS 200 may be used in the header, and, in the
payload, an identifier indicating the MS 100, for
example, the MAC address or the basic CID of the MS
100, may be included. Thereby, the RS 200 can
determine which MS has the support function.
It is noted that, in a process in which
the RS 200 relays the messages between the MS 100
and the BS 300, the information included in the
messages may be obtained by the RS 200. For example,
the MAC address, the basic CID, the primary CID of
the MS 100, and also, the support functions notified
of by the SBC-REQ/RSP messages, can be managed not
only by the BS 300 but also by the RS 200.
The RS 200 which has received the SBC-RSP
message transfers it to the MS 100 as it is (19) .
FIGS. 10 through 13 show a processing flow
of the RS 200 when receiving the ranging code from
the MS 100, a processing flow of the RS 200 when
receiving the RNG-REQ from the MS 100, a processing
flow of the RS 200 when receiving the RNG-RSP from
the BS 300 and a processing flow of the BS 300 when
receiving the RNG-REQ, respectively.
Further, a block configuration example of
the BS 300 in the second embodiment of the present
invention is the same as that of the BS 300 in the
first embodiment described above.
With reference to the block configuration
of the BS 300 shown in FIG. 6, as well as the
processing flow of FIG. 13, the operation of the BS
300 will now be described.
After receiving a message (Yes in S101 of
FIG. 13), the BS 300 extracts a control message
(RNG-REQ) from the received message, and gives it to
the ranging control part 26.
The ranging control part 26 analyzes the
RNG-REQ message, analyzes the CID included in the
header of the message, carries out control described

below, and requests the control message generation
part 25 to generate and transmit an RNG-RSP message.
When the CID is a CID for initial ranging
(IR) (No in S102), this means that the message
corresponds to a ranging request message from the MS
100 or the RS 200 belonging to the BS 300, and thus,
it is notified to the control message generation
part 25 to generate the RNG-RSP message including
the MAC address included in the RNG-REQ, the
"success" status, the basic CID and the primary CID
when correction of the frequency, transmission power
and timing of the MS 100 is not necessary, and
transmit it with CID=IR (S115). When the correction
is necessary, it is notified to the control message
generation part 25 to generate the RNG-RSP message
including the MAC address included in the RNG-REQ,
the "continue" status, and the necessary correction
information, and transmit it with CID=IR (S115).
When the CID is not for IR but is the
basic CID of the MS 100 (Yes in S102 and No in S103),
periodic ranging of the MS 100 is carried out (Sill) .
The same as the above-mentioned case for IR, it is
notified to the control message generation part 25
to generate the RNG-RSP including the contents
depending on whether or not the correction is
necessary, and transmit it with the use of the basic
CID of the RNG-REQ.
When the CID is not for IR but is the
basic CID of the RS 200 (Yes in S103), processing to
carry out differs according to whether or not a "New
MS" indicator is included in the payload part of the
RNG-REQ message.
When the "New MS" indicator is not
included (No in S104), processing to carry out
differs according to whether or not the MS MAC
address (MSID) exists. When the MS MAC address does
not exist (No in S105), periodic ranging of the RS

200 is carried out (Sill). When the MS MAC address
exists (Yes on S105), the received RNG-REQ message
means a message relayed by the RS 200 after being
transmitted from the MS 100. At this time, the MS
MAC address in the RNG-REQ message and the basic CID
included in the header of the RNG-REQ message are
managed with association to one another (S108), and
thus, the RS 200 currently connected from the MS 100
can be identified. Next, it is notified to the
control message generation part 25 to generate the
RNG-RSP message including the basic CID and the
primary CID to allocate to the MS 100, and transmit
it with the use of the CID of the basic CID of the
RS 200 (S112). The association between the MS 100
and the RS 200, as well as the basic CID and the
primary CID of the MS 100, are managed by an MS
management table stored in the storage part.
When the "New MS" indicator exists (Yes in
S104), it is determined whether or not the new MS
100 is acceptable (S106). This determination can be
made from busy conditions of the respective
resources, such as busy conditions of the radio
resources, a busy condition in the management table
and so forth. When the new MS 100 is acceptable
(Yes in S106), it is notified to the control message
generation part 25 to generate the RNG-RSP message
including a "success" status and UL-MAP including
CDMA_Allocation-IE, and transmit it with the use of
the basic CID of the RS 200, when the status in the
RNG-REQ is "success" (Yes in S107, then, S109 and
S113). When the status included in the RNG-REQ is
not "success" (No in S107), it is notified to the
control message generation part 25 to generate the
RNG-RSP message including the status from the RNG-
REQ, and correction values for the transmission
parameters, and transmit it with the use of the
basic CID of the RS 200 (S114). The

CDMA_Allocation-IE is created based on information
concerning the code notified of by the RNG-REQ. On
one hand, when the new MS 100 is not acceptable (No
in S106), it is notified to the control message
generation part 25 to generate the RNG-RSP message
including an "abort" status, and transmit it with
the use of the CID, the same as that of the RNG-REQ,
to the RS 200 (S110) .
With reference to FIG. 14 showing a block
configuration of the RS 200, as well as the
processing flows of FIGS. 10, 11 and 12, the
operation of the RS 200 will now be described.
The block configuration of FIG. 14 is
basically the same as that of FIG. 8. However,
since the generation of the MAP information is not
necessary, a MAP information processing part 46 is
provided, instead of the MAP information generation
and analysis part 36 of FIG. 8. The other parts are
the same as those of FIG. 8, and the duplicated
description is omitted.
When the ranging code (for initial ranging,
handover ranging or such) is received from the MS
100 (Yes in S61 of FIG. 10), the code reception part
37 determines whether or not correction of the
frequency of the reception signal, reception power
level and timing is required, and notifies the
ranging control part 39 of its status
(success/abort/continue), code reception information,
for example, a frame number, sub-channel, code value
of the received code and so forth. When the
correction is necessary, the correction values to be
directed to the MS 100 are also given to the ranging
control part 39. Also, the correction values may be
stored in the storage part.
The control message extraction part 35
extracts the control message (RNG-REQ, RNG-RSP or
such) from the received message, gives it to the

ranging control part 39, and gives the MAP data
received from the BS 300, and the MAP data received
via the data region of the MMR link to be
transmitted to the MS 100, to the MAP information
processing part 46.
When receiving information from the code
reception part 37, the ranging control part 39
notifies the control message generating part 40 to
generate and transmit the "New MS" indicator and the
status (success/abort/continue) to the BS 300 with
the basic CID of the RS 200 (S62, S63 of FIG. 10).
When the status is "continue", the correction values
are also notified of to the control message
generation part 40.
When receiving the RNG-REQ message from
the control message extraction part 35 (Yes in S71
of FIG. 11), the ranging control part 39 determines
whether or not the header of the message has a CID
for initial ranging (S72). When it is the CID for
IR (Yes), it is notified to the control message
generation part 40 to transmit the message to the BS
300 after changing the CID field in the header of
the received RNG-REQ message into the basic CID of
the RS 200 (S73, S75 of FIG. 11). When the CID is
not the CID for IR (No in S72), that is, when the
CID is the basic CID of the MS 100, it is notified
to the control message generation part 40 to add to
the received RNG-REQ message the status and, if
necessary, the correction information for the
frequency, reception power level and timing, and
transmit it to the BS 300 with the basic CID of the
MS 100 (S74 and S75).
When receiving the RNG-RSP message from
the control message extraction part 35 (Yes in S81
of FIG. 12), the ranging control part 39 first
determines whether or not the CID is the CID for
initial ranging (S82). When it is the CID for IR

(No), the ranging control part 39 carries out
initial ranging processing of the RS 200 (S86).
That is, when the MAC address included in the RNG-
RSP is the MAC address of itself, the basic CID and
the primary CID in the message are stored in the
storage part, and are used for
transmission/reception of subsequent control
messages. On one hand, when a CID other than the
CID for IR is included in the message (Yes in S82),
processing to then carry out differs according to
whether or not the "New MS" indicator is included in
the message (S83). When the "New MS" indicator is
included (Yes), it is notified to the control
message generation part 40 to generate an RNG-RSP
message including a "success" status and return it
to the MS 100 with the CID for IR (S88), when the
"success" status is included in the message (Yes in
S84). When no "success" status is included in the
message (No in S84), it is notified to the control
message generation part 40 to generate the RNG-RSP
message including the "abort" status and return it
to the MS 100 with the CID for IR (S87). On one
hand, when no "New MS" indicator is included in the
message (No in S83) and, MSID, i.e., the MS MAC
address is included in the message (Yes in S85), it
is notified to the control message generation part
40 to convert the CID field in the header of the
received RNG-REQ into the CID for IR, and transmit
it to the MS 100 (S89). When MSID does not exist
(No in S85), the RS 200 adjusts the frequency,
transmission power and timing according to the
correction information included in the RNG-RSP, as
the periodic ranging processing of the RS 200 itself
(S90) .
The MAP information processing part 46
carries out controlling of the PDU generation part
41 for creating the MMR link according to the MAP

data of the BS 300 transferred from the control
message extraction part 35. Further, it controls
the PDU generation part 41 and so forth, for
transmitting the MAP data to be transmitted to the
MS 100, which has been received from the BS 300 via
the MMR link.
In the second embodiment described above,
when the RS 200 receives the ranging code from the
MS 100, the RS 200 transmits the code reception
information to the BS 300. As a result, the BS 300
should not generate the code reception information,
and thus, the processing load of the BS 300 is
reduced.
Further, in the second embodiment, another
MMR link, than the transmission region of the
ranging signal, defined by the MAP data transmitted
to the RS 200 and so forth, belonging to the BS 300,
is used to transmit the code reception information
to the BS 300. As a result, collision with the
ranging signal of another MS 100, also belonging to
the BS 300, can be reduced.
Further, also in this embodiment, the
transmission region defined by the MAP data
transmitted by the BS 300 and the transmission
region defined by the MAP data transmitted by the RS
200 may have such a relationship that they are
separated by means of timing, by means of the
frequency (sub-channel) or by means of the spread
code or such, so that radio communication are not
obstructed by one another. For this purpose, the BS
300 should generate appropriate MAP data.
[c] Description of third embodiment:
In a third embodiment of the present
invention, degradation in the transmission
efficiency, otherwise occurring due to a fact that a
radio communication environment between the BS and

the RS and a radio communication environment between
the RS and the MS may not be identical to one
another can be controlled.
It is noted that, in this embodiment, one
example of an authentication sequence is described,
which may be carried out subsequent to the ranging
and basic capability registration sequence described
above for the first and second embodiments.
FIG. 15 shows the authentication sequence
which should be preferably carried out after the end
of the ranging and basic capability registration
sequence.
In this embodiment, the MS 100 carries out
the authentication sequence after finishing the
ranging and basic capability registration sequence.
First, the MS 100 transmits its own
authentication data (for example, an electronic
certificate including the MS's public key) to the RS
200 with the use of a PKMv2-REQ message (1). In FIG.
15, an example is shown in which, in the PKMv2-REQ
message, an EAP (Extensible Authentication Protocol:
RFC2284) packet is encapsulated. It is noted that,
at this time, the primary CID obtained previously is
used as the connection ID. Thereby, both of the RS
200 and the BS 300 can easily identify the MS 100.
The RS 200 which has thus received the
PKMv2-REQ (EAP-transfer) relays the message to the
BS 300 (2). There, it is not necessary to decrypt
cipher at the RS.
The BS 300 which has thus received the
PKMv2-REQ (EAP-transfer) transfers the electronic
certificate to an external server to obtain an
authentication result, and thus, carries out
authentication. When the authentication is
succeeded in, an authentication key (AK) to be
shared by the MS 100 and the BS 300 is then
generated, and also, to the MS 100, a PKMv2-RSP

(EAP-transfer) including the authentication key (AK
or a parameter for generating AK) is generated,
which is then returned to the RS 200 (3). At this
time, preferably, the AK or the parameter for
generating the AK is encrypted with the use of the
public key included in the electronic certificate of
the MS 100. Thereby, only the MS 100 itself, which
has the corresponding private key, can decrypt, and
thus, it is possible to achieve safe transfer of the
authentication key information.
The RS 200 which has thus received the
PKMv2-RSP (EAP-transfer) relays the message to the
MS 100 (4). At this time, the RS 200 does not have
the private key, and thus, cannot decrypt the
encrypted authentication key information.
On one hand, the BS 300 transmits a PKMv2-
RSP (key-transfer (AK)) including data obtained from
encrypting the authentication key information (AK or
the parameter for generating AK), to the RS 200, in
order that the authentication key used with the MS
100 is also shared with the RS 200 (5). In the
encryption, it is preferable to use the key, shared
when the RS 200 has carried out the authentication
to connect with the BS 300. The RS 200 stores the
authentication key information.
The MS 100 which has thus received the
PKMv2-RSP (EAP-transfer) detects that the
authentication has been succeeded in. In order to
establish security association (i.e., an encryption
method and so forth) with the BS 300, the MS 100
transmits a PKMv2-REQ (SA-TEK-request) (6). In this
message, a calculation result (a hash value, for
example) obtained from predetermined calculation
(hash calculation or such, for example) being
carried out on the AK, obtained from the
authentication key information, previously obtained
the MS 100, and the transmission data, is added.

For example, a parameter generated from the AK is
one argument of a function F(x), and, a calculation
result F(D) is obtained as a result of the
transmission data D being substituted for x.
Further, in this message, encryption methods (for
example, AES, DES, key length information and so
forth) to require, are included.
The RS 200 which has thus received the
PKMv2-REQ (SA-TE-request) relays the message to the
BS 300.
The BS 300 which has thus received the
PKMv2-REQ (SA-TE-request) decrypts the cipher, the
same as in the previous case, refers to the
encryption methods required by the MS 100, selects a
encryption method which can be adopted, determines
SA configured by the encryption method (for example,
key length information) used between the BS 300 and
the MS 100, and returns the SA information to the RS
200 by means of a PKMv2-RSP (SA-TEK-response) (8).
It is noted that, the BS 300 checks as to whether or
not the calculation result (hash value) included in
the message agrees with a calculation result
obtained from predetermined calculation (for example,
hash calculation) with the use of the authentication
key (AK or the parameter obtained from AK) which the
BS 300 itself has (stores) and the reception data.
Thereby, the BS 300 determines whether or not the
message is one from the MS 100 which has been
authenticated and thus is authentic. When it is not
authentic, the processing should be rejected.
The RS 200 which has thus received the
PKMv2-RSP (SA-TEK-response) relays the message to
the MS 100 (9).
The MS 100 which has thus received the
PKMv2-RSP (SA-TEK-response) and thus shares the SA
with the BS 300, transmits a PKMv2-RSP (key-request)
requesting from the BS 300 an encryption key for

encrypting user data, corresponding to the SA, to
the RS 200 (10). At this time, the same as (6), the
calculation result is added for the purpose of
authentication.
The RS 200 which has thus received the
PKMv2-REQ (key-request) relays the message to the BS
300 (11) .
The BS 300 which has thus received the
PKMv2-REQ (key-request) generates an encryption key
corresponding to the SA (TEK: Traffic Encryption
Key), encrypts it with the use of the shared key
shared with the MS 100, includes it in a PKMv2-RSP
(key-replay), and transmits the message to RS 200
(12). Also at this time, the BS 300 uses the
calculation result added in the reception message,
for the purpose of authentication to check as to
whether or not the data is one from the MS 100 which
is authentic. Then, when it is authentic, the
PKMv2-RSP is transmitted to the RS 200.
The RS 200 which has thus received the
PKMv2-RSP (key-reply) relays the message to the MS
100 (13).
On one hand, the BS 300 shares the key
information (instead of the data of the key itself,
information for identifying the key, a parameter for
generating the key or such, may be used) with the RS
200. That is, the key information (in this example,
TEK, i.e., the key itself) is encrypted, and a
PKMv2-RSP (key-transfer (TEK)) including TEK, i.e.,
the thus-encrypted key, is transmitted to the RS 200.
In the encryption of the key, the key shared upon
the authentication for the purpose that the RS 200
has connected with the BS 300, is used.
In this case, TEK is used as the shared
key. However, this may also be used as another key
(private key or such).
Thus, the RS 200 can obtain AK and TEK

required for the data, transmitted/received between
the BS 300 and the MS 100.
As a result, the RS 200 can decrypt user
data (MAC-PDU) received from the MS 100 or the BS
300, and further, TEK is used for decrypting the
cipher, so that the RS 200 can obtain the
transmission data before being encrypted.
Further, the RS 200 can adjust the data
amount by modifying (dividing, combining with other
data or such) the transmission data before being
encrypted (plain language), which is obtained from
decryption of the encryption.
For example, when the available
transmission speed of data via radio between the RS
200 and the MS 100 is lower than the available
transmission speed of data via radio between the BS
300 and the RS 200, the cipher of MAC-PDU is
decrypted, and then, the data is divided into a
plurality of MAC-PDU. Then, for each of the thus-
divided data, MAC-PDU is encrypted with the use of
TEK (shared key), and/or, a predetermined
calculation result (i.e., an authentication
calculation result), obtained from each of the thus-
divided data and AK, is added, for example. After
that, the data is transmitted one by one (each
divided data being transmitted with a respective one
of different frames). As a result, it is possible
to control degradation in the transmission
efficiency, otherwise occurring due to the
difference in the radio environment. It is noted
that, the authentication calculation result may not
be added when the user data is transmitted, but may
be added only when the control data is transmitted
(the same manner may be applied also in the
subsequent processing).
On the other hand, when the available
transmission speed of data via radio between the RS

200 and the MS 100 is higher than the available
transmission speed of data via radio between the BS
300 and the RS 200, MAC-PDU obtained from decryption
with the use of TEK is combined together, then the
combined result is again encrypted with the use of
TEK, and/or, a predetermined calculation result with
the use of AK is added thereto, and then, is
transmitted within one frame. As a result, it is
possible to avoid useless transmission, and to
allocate the thus-saved resource to another radio
communication.
The reason why the cipher decrypted is
again encrypted by the RS 200 is as follows: Since,
when receiving MAC-PDU from the RS 200, the MS 100
tries to decrypt it as one unit, and thus, an error
may occur when decrypting is tried on incomplete
data. Especially when the MS 100 does not
distinguish as to whether it carries out radio
communication with the RS 200 or the BS 300, a
trouble may occur when data modification is thus
made by the RS 200. The same situation may occur
also when data is combined as mentioned above.
Further, as a result of the RS 200 checking, with
the use of AK, authenticity of the authentication
calculation result added to the control message
transmitted from the MS 100 or the BS 300, it is
possible to prevent transfer of non-authentic packet,
and thus, it is possible to effectively use the
radio resources.
A configuration of a relay station in the
third embodiment is shown in FIG. 8.
The above-mentioned message received from
the MS 100 or the BS 300 is given to the control
message generation part 40 after being extracted by
the control message extraction part 35.
The message transmitted to the MS 100 or
the BS 300 is generated and transmitted in such a

manner that the control message generation part 40
generates a transmission control message based on
the received control message which is then given to
the PDU generation part 41.
For example, in FIG. 15, the same message
may be used between (1) and (2), between (3) and (4),
between (6) and (7), between (8) and (9), between
(10) and (11) and between (12) and (13). The
control message generation part 40 may not encrypt
the reception message, may give it as it is to the
PDU generation part 41, and thus, may transmit it
from the PDU generation part 41.
On one hand, as to the messages of (5) and
(14) in FIG. 15, the message is given to the
encryption processing part 45 from the control
message extraction part 35 since it is one for the
RS 200, according to the CID. The encryption
processing part 45 decrypts the cipher with the use
of the key shared between the RS 200 and the BS 300,
thus obtains information such as AK which is the
authentication key information (or the parameter for
generating AK), TEK which is the encryption key
information and so forth, and stores them.
When the dividing or combining of the data
is to be carried out as mentioned above, the
encryption processing part 45 takes the transmission
packet from the packet buffer part 38, decrypts the
cipher with the use of TEK, and then carries out the
above-mentioned dividing or combining of the data.
The thus-modified data is then again encrypted with
the use of TEK (i.e., encryption in the same type as
that in which the BS 300 carries out the encryption),
and the thus-encrypted data is then given to the
packet buffer part 38. Thus, the data after being
thus modified can be transmitted.
It is noted that, the transmission region
is defined by the MAP information generation and

analysis part 36, corresponding to the thus-modified
data, and the data is thus transmitted.
Further, when the authentication data is
required, the encryption processing part 45 carries
out the predetermined calculation with the use of AK
(or the parameter for AK) which is stored in the
same manner, and the transmission data, encrypts the
data with the use of TEK, to which data the
calculation result has been added, and then, gives
it to the packet buffer part 38. It is noted that,
the authentication calculation result added by the
MS 100 may be deleted at this time.
It is noted that, when the radio
communication system adopts an automatic repeat
request (ARQ) control system, the BS 300 transmits
the data, after adding identification information
for each transmission data such as a sequence number
or such.
In this case, in the RS 200, as a result
of the sequence number encrypted being decrypted,
automatic repeat request control can be carried out
separately between the RS 200 and the MS 100.
That is, when it is detected by the
decoding part 34 that data transmission is properly
carried out from the BS 300 to the RS 200 (i.e., it
is detected that the reception is carried out
properly from a determination with the use of a CRC
check bit added to the data), the encryption
processing part 45 decrypts the cipher, and stores
the reception data in the packet buffer 38.
Then, when transmitting to the MS 100, the
encryption processing part 45 of the RS 200 stores,
to the data to which the dividing or combining has
been carried out as mentioned above, the sequence
number separately in the same format, an then,
encrypts it, and returns it to the packet buffer
part 38. Then, the data is transmitted to the MS

100 from the transmission part 44. Thereby, the
automatic repeat request control can be carried out
between the RS 200 and the MS 100. It is noted that,
the sequence number added by the BS 300 is deleted.
It is noted that, the data to which the sequence
number has been added, i.e., which is the data
before being encrypted, is stored in the encryption
processing part 45.
That is, when the data received from the
RS 200 has an error, the MS 100 identifies the data
with the use of the sequence number which the RS 200
has added, and makes a repeat request to the RS 200.
The RS 200 receives the repeat request identifying
the sequence number from the MS 100 by the control
message extraction part 35, which then notifies the
encryption processing part 45 of the corresponding
sequence number. The encryption processing part 45
reads from the storage part the data having the
sequence number thus notified of, encrypts it with
the use of TEK, and gives the encrypted result to
the packet buffer part 38. Thus, data transmission
in response to the repeat request to the MS 100 is
thus carried out.
Further, when the RS 200 detects that the
reception data from the BS 300 has an error, the
encryption processing part 45 identifies the data
from the sequence number added by the BS 300, which
is obtained from decryption, generates a message to
notify the BS 300 of the sequence number, and gives
it to the packet buffer part 38. Thus, transmission
of the message to the BS 300 is carried out. Thus,
it is possible to send a repeat request to the BS
300 for the desired data.
The present invention is not limited to
the above-described embodiments, and variations and
modifications may be made without departing from the
basic concept of the present invention claimed below.

The present application is based on
Japanese Priority Application No. 2006-301214, filed
on November 7, 2006, the entire contents of which
are hereby incorporated herein by reference.

We claim:
1. A relay station (200) comprising:
a reception unit (32) receiving a signal sequence indicating a
connection request, from a radio terminal (100), the signal sequence
being selected by the radio terminal from among a group of
predetermined signal sequences shared by a plurality of radio
terminals;
a control unit (39, 40) generating a ranging request message
indicating that the radio terminal (100) newly requesting connection
exists; and
a transmission unit (44) transmitting the ranging request message to a
radio base station (300),
wherein the reception unit (32) is configured to measure, when the
signal sequence is received, a deviation of a transmission parameter of
the radio terminal (100) in the received signal sequence from a
standard transmission parameter, and the control unit (39, 40) is
configured to generate the ranging request message when the
measured deviation of the transmission parameter is within a
predetermined range.

2. A radio base station (300) for use with the relay station (200) as
claimed in claim 1 comprising:
a reception unit (12) receiving a ranging request message, transmitted
from the relay station (200) in response to reception of a signal
sequence indicating a connection request from a radio terminal (100);
a control unit (25, 26) determining in response to the reception of the
signal sequence whether not to newly permit connection with the radio
terminal (100), and generating a ranging response message including
the determination result; and
a transmission unit (24) transmitting the ranging response message to
the relay station (200).
3. The relay station (200) as claimed in claim 1, wherein:
the control unit (39, 40) is configured to generate reception information
of the signal sequence received by said reception unit (32) or
correction value information indicating a deviation from a
predetermined criterion calculated upon the reception of said reception
unit (32); and
the transmission unit (44) is configured to transmit said reception
information or the correction value information to a radio base station
(300).

4. The relay station (200) as claimed in claim 1, wherein:
the reception unit (32) is configured to receive a first ranging request
message including an identifier of the radio terminal (100), from the
radio terminal (100);
the control unit (39, 40) is configured to generate in response to the
reception of the first ranging request message a second ranging
request message including the identifier of the radio terminal (100)
and an identifier of the relay station (200); and
the transmission unit (44) is configured to transmit the second ranging
request message to the radio base station (300).
5. The relay station (200) as claimed in claim 4, wherein:
the identifier of the radio terminal (100) included in the second
ranging request message is stored in a payload or a header.
6. The radio base station (300) as claimed in claim 2, wherein:
the control unit (25, 26) is configured to store identification
information of the radio terminal (100) and the relay station (200)
included in the ranging request message, and to generate a ranging
response message corresponding to the ranging request message; and

the transmission unit (24) is configured to transmit to the relay station
(200) the ranging response message.
7. The radio base station (300) as claimed in claim 6, wherein:
said control unit (25, 26) includes in the ranging response message a
connection identifier allocated to the radio terminal (100); and
said connection identifier is stored with a correspondence to the
identifier of the radio terminal (100).
8. A radio communication method comprising the steps of:
in a relay station (200), receiving a signal sequence indicating a
connection request from a radio terminal (100) the signal sequence
being selected by the radio terminal from among a group of
predetermined signal sequences shared by a plurality of radio
terminals, generating a ranging request message indicating that the
radio terminal (100) newly requesting connection exits, and
transmitting the ranging request message to a radio base station
(300); and
in the radio base station (300), receiving the ranging request message
from the relay station (200), determining whether or not to newly

permit connection of the radio base station (300) with the radio
terminal (100), generating a ranging response message including the
determination result, and transmitting the ranging response message
to the relay station (100),
wherein, when the signal sequence is received at the relay station
(200), a deviation of a transmission parameter of the radio terminal
(100) in the received signal sequence from a standard transmission
parameter is measured, and the ranging request message is generated
at the relay station (200) when the deviation of the transmission
parameter is within a predetermined range.
9. The radio communication method as claimed in claim 8, wherein:
said ranging request message is transmitted to the radio base station
(300) when the reception of the signal sequence meets a
predetermined criterion, and is not transmitted when the
predetermined criterion is not met.

ABSTRACT

RADIO BASE STATION. RELAY STATION AND RADIO COMMUNICATION
METHOD
A relay station (200) has a reception unit receiving a signal sequence indicating a
connection request, from among a predetermined signal sequence group; a
control unit generating a ranging request message indicating that a radio
terminal newly requesting connection exists; and a transmission unit transmitting
the ranging request message to a radio base station (300).