KR20090067163A - Radio base station, relay station, and communication control method - Google Patents

Abstract

A radio base station performs data transmission to/from radio terminals under control of each of a plurality of relay stations via the relay stations. The radio base station comprises a control unit for transmitting first data addressed to a first radio terminal under control of a first relay station and second data addressed to a second radio terminal under control of a second relay station at timings which are overlapped at least partially.

Description

Wireless base station, relay station, and communication control method {RADIO BASE STATION, RELAY STATION, AND COMMUNICATION CONTROL METHOD}

The present invention relates to a wireless base station, a relay station, and a communication control method using wireless communication. Specifically, the present invention relates to a radio base station and the like which improves the use efficiency of a frequency to be used.

In IEEE802.16WG, which is taken as an example of a wireless communication system, mainly IEEE802.16d (for example, non-patent document 1 below) for fixed communication use, and IEEE802.16e (for example, for mobile communication use) Two types of the following nonpatent literatures 2) are prescribed.

Fig. 22 shows a service image of such IEEE802.16d and IEEE802.16e. It is based on a point-to-multipoint (P-MP) type connection in which a plurality of terminals 101 to 103 are connected to one wireless base station 100.

As described above, since IEEE802.16d and the like are based on P-MP type connection, the service area is limited to the cover area (cell) covered by the wireless base station 100, and there is a problem that the communication rate is lowered at the cell edge. .

In order to solve this problem, the IEEE802.16WG has initiated a review of a relay station which relays communication between a wireless base station and a wireless terminal (IEEE802.16j).

Fig. 23 is a diagram showing an example of the network configuration of IEEE802.16j. 23 shows an example of arranging relay stations RS in order to improve communication rates of two radio terminals MS # 1 and MS # 2 located near the cell edge of the radio base station BS.

On the other hand, in IEEE802.16d and IEEE802.16e, the wireless terminal MS communicates with the wireless base station BS and the wireless terminal MS in accordance with MAP information transmitted from the wireless base station BS.

Here, the MAP information includes radio resources (frequency channel and time (transmission timing): hereinafter referred to as "burst") used by the radio terminal MS for communication, burst modulation schemes and encoding schemes, and radio communication targets. Terminal MS is specified. The MAP information includes a DL-MAP message in the downlink direction and a UL-MAP message in the uplink direction.

FIG. 24 shows an example of a DL-MAP message, and FIG. 25 shows an example of a Burst Profile DL-MAP IE (hereinafter referred to as "DL-MAP IE") included in the DL-MAP message. One or more DL-MAP IEs are inserted into the "DL-MAP_IE for OFDMA PHY" field of the DL-MAP message (n in the example of FIG. 24).

As shown in FIG. 25, the DL-MAP IE has a "DIUC" field and a "CID" field. In the "DIUC" field, a code indicating a burst modulation scheme and a coding scheme (including the encoding rate) is inserted. In the "CID" field, the identifier of the connection of the packet included in the burst is inserted, and the wireless terminal MS selects the burst to decode by recognizing the CID.

Fig. 26 is a diagram illustrating an example of allocation of downlink bursts by the DL-MAP IE. Each burst is designated by "Symbol Offset" of the DL-MAP IE, and the wireless terminal MS communicates with the wireless base station BS by the allocated transmission area (frequency (vertical axis) and time (horizontal axis)).

FIG. 27A shows an example of an UL-MAP message, and FIG. 27B shows an example of a Burst Profile UL-MAP IE (hereinafter, referred to as "UL-MAP IE") included in the message. Drawing.

As shown in FIG. 27B, the UL-MAP IE includes fields of "CID", "UIUC", and "Duration".

In the "CID" field, an ID for identifying a wireless terminal MS to which a burst has been assigned is inserted. In the "UIUC" field, a code indicating a modulation method and a coding method (including a coding rate) of the burst is inserted. ", The amount of bandwidth to be allocated (number of slots) is inserted.

28A and 28B are diagrams showing examples of allocation of uplink bursts by the UL-MAP IE. As shown in these figures, allocation of uplink bursts is basically defined by the number of slots. That is, each slot is sequentially allocated in the direction of the time axis (Symbol direction: horizontal axis), and the slot number specified in "Duration" is allocated while moving to the next Subchannel (vertical axis) from the cut-off point of the Uplink Zone. Then, the first slot of the next burst is allocated to continue from the last slot of the immediately preceding burst.

As shown in Figs. 28A and 28B, the allocation of uplink bursts is different from the case of the downlink represented by the quadrangles by the number of Subchannnel and the number of Symbols. It becomes the form that there is.

As shown in Fig. 28C, each burst is sequentially assigned to the uplink burst in the order of UL-MAP IE ("Burst Profile IE Burst # 1 ..." in the figure).

[Non-Patent Document 1] IEEE Std802.16-2004

[Non-Patent Document 2] IEEE Std802.16e-2005

However, the allocation of radio resources by the aforementioned DL-MAP message or UL-MAP message is an example performed between the radio base station BS and the radio terminal MS. Therefore, when a relay station RS exists between the radio base station BS and the radio terminal MS, it has been required to allocate radio resources appropriately.

In addition, when allocating radio resources, it is desirable to increase the utilization efficiency of frequencies as much as possible. This is because the throughput can be improved.

Accordingly, the present invention has been made in view of the above problems, and an object thereof is to provide a radio base station, a relay station, and a communication control method capable of allocating appropriate radio resources when performing radio communication between a radio terminal and a radio base station through a relay station. To provide.

Another object of the present invention is to provide a radio base station and the like which improves the efficiency of using a frequency.

Means for solving the problem

In order to achieve the above object, according to an embodiment of the present invention, in a wireless base station that transmits data to and from a wireless terminal under management of each relay station through a plurality of relay stations under management, the first relay station includes: The radio frame configuration is such that a part of the first transmission area for the first wireless terminal under the control of the relay station and the second transmission area for the second wireless terminal under the control of the second relay station from the second relay station overlap in part or all. And a map information generation unit for generating map information to be displayed, and a transmission unit for transmitting the map information.

Further, in order to achieve the above object, according to another embodiment of the present invention, in a relay station relaying data between a wireless terminal under management and a wireless base station, the first data in front of the wireless terminal under management and the relay station are different from each other. And another different relay station having a control unit for transmitting the first data in a transmission area in which part or all of the second data in front of the second wireless terminal under another relay station is overlapped.

Further, in order to achieve the above object, according to another embodiment of the present invention, communication control in a wireless communication system for transmitting data between each wireless terminal under management of each relay station and a wireless base station through a plurality of relay stations under management; In the method, first data in front of a first wireless terminal under management of a first relay station and second data in front of a second wireless terminal under management of a second relay station are respectively transmitted from the wireless base station to the first relay station and the second relay station. And transmit the first data and the second data from the first relay station and the second relay station so as to partially or completely overlap the transmission area.

Effect of the Invention

According to the present invention, when wireless communication is performed at a wireless terminal and a wireless base station via a relay station, a wireless base station, a relay station, and a communication control method capable of allocating appropriate radio resources can be provided. In addition, it is possible to provide a radio base station and the like with improved frequency utilization efficiency.

1A is an example of a subframe, and (B) and (C) are examples of transmission.

2 is a block diagram illustrating an example of a block configuration of a wireless base station.

3A is an example of a wireless communication system management table, (B) is an example of a wireless terminal communication path management table, and (C) is an example of a non-interfering relay station management table.

4 is a flowchart showing an example of band allocation processing.

5A illustrates an example of DL-MAP IE, and FIG. 5B illustrates an example of a subframe.

6A and 6B show an example of data transmission.

7 is a diagram showing a block configuration example of a relay station.

8 is a diagram illustrating a distribution example of a wireless terminal.

9A and 9B are diagrams showing examples of DL-MAP information and data transmission.

10 is a flowchart showing an example of band allocation processing.

11 is a diagram illustrating a distribution example of a wireless terminal.

12A and 12B show examples of DL-MAP information and data transmission.

13 is a flowchart illustrating an example of band allocation processing.

14 is a diagram showing an example block configuration of a wireless base station.

Fig. 15 is a diagram showing an example block configuration of a wireless base station.

16A illustrates an example of an RS-MAP message, and FIG. 16B illustrates an example of an RS-MAP IE.

17A and 17B show an example of a subframe, and (C) and (D) show an example of data transmission.

18 is a flowchart showing an example of band allocation processing.

19 is a flowchart showing an example of band allocation processing.

20 is a flowchart showing an example of band allocation processing.

21A and 21B show an example of a subframe, and (C) and (D) show an example of data transmission.

22 is a diagram illustrating an example of a service image.

23 is a diagram illustrating an example of a network configuration using a relay station.

24 illustrates an example of a DL-MAP message.

25 is a diagram illustrating an example of DL-MAP IE.

26 is a diagram illustrating an example of a subframe.

27A illustrates an example of an UL-MAP message, and FIG. 27B illustrates an example of an UL-MAP IE.

28A and 28B are examples of allocation of uplink bursts, and (C) are examples of UL-MAP messages.

<Explanation of symbols for the main parts of the drawings>

11: receiver

14: communication path determining unit

15: wireless terminal communication path management unit

16: Communication method decision unit

17: wireless terminal communication method management unit

18: Non-Interfering Relay Station Administration

19: wireless frame configuration information generation unit

20: packet identification unit

25: relay station transmit power control information generation unit

26: control information extraction unit

27: band request analysis unit

28: relay station band allocation information generation unit

31: receiver

32: control message extractor

35: MAP information interpreter

36: control message generator

T1: wireless terminal communication method management table

T2: wireless terminal communication path management table

T3: Non-Interfering Relay Station Management Table

MS: wireless terminal

RS: relay station

BS: wireless base station

Best Mode for Carrying Out the Invention

Best Mode for Carrying Out the Invention The following describes the best mode for carrying out the present invention.

<First Embodiment>

First, the first embodiment will be described.

The first embodiment is an example in which radio resources are appropriately allocated when radio communication is performed through the relay station RS in the radio base station BS and the radio terminal MS.

FIG. 1A is a diagram illustrating an example of a subframe in the downlink direction (where the horizontal axis represents time (transmission timing) and the vertical axis represents frequency channel).

As shown in Fig. 1A, the radio resources are allocated to be transmitted simultaneously using half the frequency bands for each of the relay stations RS # 1 and RS # 2. The radio resources MS # 1 and MS # 2 are also allocated radio resources such that they are simultaneously transmitted using half of the frequency bands. The DL-MAP message can be assigned by setting such that the transmission areas (frequency channel and time) do not overlap between the bursts.

By the assignment of such radio resources, data is transmitted from the radio base station BS to the relay stations RS # 1 and RS # 2 simultaneously using different frequency bands (see Fig. 1B). Next, data is simultaneously transmitted from the relay stations RS # 1 and RS # 2 to the wireless terminals MS # 1 and MS # 2 under management (see Fig. 1C).

As described above, in the communication between the radio terminal MS and the radio base station BS through the relay station RS, separate radio resources are allocated to the radio terminals MS # 1 and MS # 2 under the management of the relay stations RS # 1 and RS # 2. Wireless resources can be allocated.

Second Embodiment

Next, a second embodiment will be described.

In the first embodiment, the radio resources are allocated to the relay station RS and the radio terminal MS under management so that the transmission area (frequency channel, transmission timing) does not overlap. However, a plurality of relay stations RS exist under the management of the radio base station BS, and each relay station RS is disposed at a position where there is no interference (for example, the cover area of each relay station (area for providing wireless communication service to the wireless terminal) is overlapped). Different radio resources have been allocated.

Therefore, in the second embodiment, the radio base station BS manages relay stations RS which are not interfered with each other, and communicates by the same burst profile (combination of modulation and coding schemes) among the radio terminal MSs under such relay station RS management. DL which allocates the downlink burst allocation (the radio resource allocation in the downlink direction) to the wireless terminal MS in the same burst (transmission area) region (Symbol time and frequency channel (subchannel)) in the downlink subframe. The radio base station BS generates and transmits the MAP. As a result, since the same transmission area (frequency channel) can be used for a plurality of wireless terminal MSs at the same time, the efficiency of using the frequency can be improved. Further, the allocation of radio resources in the uplink direction will be described in detail in the fifth embodiment.

The radio communication system composed of the radio terminal MS, the plurality of relay stations RS, and the radio base station BS under the management of the relay station RS is applied in the same manner as in the first embodiment. Hereinafter, the present invention will be described in detail with reference to FIGS. 2 to 7.

Fig. 2 is a diagram showing an example of the configuration of the radio base station BS in the second embodiment. The wireless base station BS includes a receiving unit 11, a packet reproducing unit 12, an NW interface unit 13, a communication path determining unit 14, a wireless terminal communication path managing unit 15, and a communication method determining unit. 16, the wireless terminal communication system management unit 17, the non-interfering relay station management unit 18, the radio frame configuration information generation unit 19, the packet identification unit 20, the packet buffer unit 21, And a PDU generator 22 and a transmitter 23.

The reception unit 11 receives the PDU (Protocol Data Unit) including the user data through the antenna 24, and outputs it to the packet reproduction unit 12. The PDU is reconstructed into an IP (Internet Protocol) packet or the like by the packet reproducing unit 12 and transmitted to the upper network via the NW interface unit 13.

In addition, the reception unit 11 may provide downlink radio channel performance information (eg, CINR: Carrier to Interface and Noise Ratio) measured by the wireless terminal MS and the uplink radio channel measured by the reception unit 11. The information, or the radio channel performance information of the uplink measured and transmitted by the relay station RS, is output to the communication method determination unit 16.

The communication method determination unit 16 determines, from the radio channel performance information, the communication method (modulation method, error correction coding method, and coding rate) for each wireless terminal MS, and transmits the information to the wireless terminal communication method management unit 17. Output

The wireless terminal communication method management unit 17 holds the wireless terminal communication method management table T1 and stores this information. An example of the wireless terminal communication method management table T1 is shown in Fig. 3A. As shown in Fig. 3A, the modulation scheme "Modulation" (for example, QPSK, 16QAM) and the error correction code coding scheme "FEC" (Forward Error Correction) used for each wireless terminal MS (example For example, a convolutional code and a turbo code, and coding rates (for example, 1/2, 3/4) are shown.

In addition, when the wireless channel performance is good, the communication method selects a combination of communication methods that enable higher speed communication, and when not, selects a combination of communication methods that enable slower communication. That is, so-called AMC (Adaptive Modulation Control) is performed.

The communication path determining unit 14, based on the radio channel performance information between each of the radio terminal MS, the radio base station BS, and the relay station RS, transmitted from the receiver 11, optimizes the effective use of radio resources. A communication path to be determined is determined, and the information is output to the wireless terminal communication path manager 15.

For example, in the wireless terminal MS, when the CINR of the received signal from the relay station RS1 is better than the CINR of the received signal from the radio base station BS, a path via the relay station RS1 is selected.

The radio terminal communication path management unit 15 holds the radio terminal communication path management table T2 and stores such information. An example of the wireless terminal communication path management table T2 is shown in FIG. 3B. In the example shown in FIG. 3B, wireless terminal MS # 1 is the best communication path for communication via relay station RS # 1, and wireless terminal MS # 3 is the best communication path for direct communication with wireless base station BS. do.

The non-interfering relay station management unit 18 grasps the presence or absence of interference between each relay station RS at the time of the installation of the relay station RS, and stores the information in the non-interfering relay station management table T3. An example of the non-interfering relay station management table T3 is shown in Fig. 3C. In this example, the relay station RS # 1 and the relay station RS # 2 show that there is no mutual interference with each other. Such information is, for example, the presence or absence of interference by receiving a carrier sense for the radio signal from the neighboring relay station RS by the relay station RS or the CINR of the received signal from the neighboring relay station RS from the wireless terminal MS under management. Can be determined and stored in the table T3. That is, when the reception signal from the neighboring relay station RS is above a predetermined level, the interference is assumed to be present, or when the CINR report from the wireless terminal MS indicates that a signal of CINR exceeding the reference value is received from the neighboring relay station. It is to be.

Of course, it is also possible to calculate whether or not to interfere with each other from the arrangement positions of the plurality of relay stations and the transmission outputs, to create and store the table.

The NW interface unit 13 receives an IP packet or the like from an upper network, and outputs it to the packet identification unit 20. The packet identification unit 20 identifies a wireless terminal MS or a quality of service (QoS) class to be received from information such as an IP header, and requests bandwidth allocation from the radio frame configuration information generation unit 19. In addition, an IP packet or the like is output to the packet buffer unit 21. The CID is specified by identification of the wireless terminal MS as the destination.

The radio frame configuration information generation unit 19 manages the communication method (modulation method, error correction code) of the radio terminal MS corresponding to each CID for which the band is requested, and manages the radio terminal communication method of the radio terminal communication method management unit 17. Obtained from table T1. The radio frame configuration information generation unit 19 communicates with the radio base station BS directly from the radio terminal communication path management table T2 of the radio terminal communication path management unit 15, or relays the relay station RS when relaying the relay station RS. Get a wife. In addition, the radio frame configuration information generation unit 19 acquires the presence or absence of mutual interference between the target relay stations RS from the non-interfering relay station management table T3 of the non-interfering relay station management unit 18.

The radio frame configuration information generation unit 19 generates a DL-MAP message that defines the band allocation of the radio frame based on these information, and transmits the same through the PDU generation unit 22 and the transmission unit 23. The necessary data packets before the relay station RS and the radio terminal MS are read from the packet buffer unit 21 and transmitted via the PDU generation unit 22 and the transmission unit 23.

4 is a flowchart of band allocation processing for the wireless terminal MS, which is performed at the wireless base station BS. The radio frame configuration information generating unit 19 executes.

First, it is judged whether or not it is band allocation timing for the wireless terminal MS (S11). Whether or not it is allocation timing is determined by whether or not the time for generating map information for one frame has arrived, for example, since map information is created for each frame.

If it is not the assignment timing (No in S11), it waits until the corresponding timing is reached. When the allocation timing is reached (Yes), the candidate of the wireless terminal MS to which the band is allocated is extracted (S12). Extraction is performed by the destination wireless terminal MS from the packet identification unit 20.

Next, the wireless terminal communication path management table T2 is searched to obtain a communication path of the candidate wireless terminal MS (S13).

Next, a band is allocated to the wireless terminal MS communicating with the wireless base station BS directly from the candidate wireless terminal MS (S14). That is, in the DL-MAP message, the downlink transmission area assigned to this wireless terminal MS is defined.

Next, the non-interfering relay station management table T3 is searched for, and the wireless terminal MS under non-interfering relay station management is grouped (S15).

Next, the wireless terminal communication method management table T1 is searched, and the group is further subdivided into a wireless terminal MS of the same communication method (modulation method and error correction coding method) (S16).

Next, after subdividing, the same radio resource is allocated to the wireless terminal MSs of the same group (S17). That is, in the DL-MAP message, the same downlink transmission area is defined for the wireless terminal MS belonging to the same group.

Next, if there is no unassigned band (YES in S18), DL-MAP data is generated and transmitted. The process then returns to S11 to repeat the above-described processing. If there is an unassigned band (NO in S18), the process proceeds to S12 and the above-described processing is repeated.

Further, in the transmission area defined by the DL-MAP data, data transmission is directly performed from the radio base station BS to the radio terminal MS, and is also different from each of the plurality of relay stations RS to each radio terminal MS under management. Transmission of the data including the contents is performed.

More specifically, there are relay stations RS1, 2, and 3 that do not interfere with each other, wireless terminals MS11, 12 exist under the management of relay station RS1, and wireless terminals MS21, 22 exist under the management of relay station RS2. It is assumed that the wireless terminal MS31 exists under the management of the relay station RS3.

It is assumed that the wireless terminals MS11, 21, and 31 correspond to the same communication scheme, and the wireless terminals MS22, 32 correspond to the same communication scheme.

At this time, when defining the downlink transmission area in the DL-MAP, at least a part of the downlink transmission areas (transmission timing, transmission subchannel) of MS11, 21, 31 are overlapped. Preferably, the transmission area is made the same. In addition, at least a part of the downlink transmission bands (transmission timing, transmission subchannel) of MS12 and 22 are overlapped (including a relationship in which one transmission area is included in the other transmission area). Preferably, the transmission area is made the same.

In order to be able to transmit data from the relay station RS to each wireless terminal MS in the defined band, the data before MS11 and 12 for RS1, the data before MS21 and 22 for RS2, and the data before MS31 for RS3 are transmitted to each MMR. Transmit via a link (communication link between a wireless base station BS and a relay station RS).

By this process, the same radio resource is allocated to the radio terminal MS using the same communication scheme for the radio terminal MS under the management of the relay station RS which does not interfere with each other from among the plurality of relay stations RS.

FIG. 5A shows an example of a DL-MAP IE generated by the process of band allocation, and FIG. 5B shows an example of a downlink subframe.

In the DL-MAP IE shown in FIG. 5A, two CIDs (CID of wireless terminal MS # 1 and CID of wireless terminal MS # 2) define one DL-MAP IE that defines one transmission area. As defined in FIG. 5 and "Symbol Offset", as shown in FIG. 5B, two radio terminals MS # 1 and MS # 2 are arranged in one burst. In one burst, it is allowed to transmit data from different relay stations RS (here RS # 1, RS # 2) to a plurality of wireless terminal MSs (here, wireless terminals MS # 1, MS # 2) under management, respectively. Will be.

In addition, since "DIUC" of the DL-MAP IE inserts a code value indicating a combination of a modulation method and an error correction coding method, the two wireless terminals MS # 1 and MS # 2 have a common modulation method and an error correction code. To communicate.

In addition, the frame | frame shown by RS # 1 and RS # 2 represents the MMR link between radio base station BS and relay station RS # 1, and the MMR link between radio base station BS and relay station RS # 2, respectively. Preferably, the radio base station transmits data to the relay station RS to the relay station RS using the MMR of the same subframe as the transmission bands of the bursts indicated by MS # 1 and MS # 2. That is, data for MS # 1 in RS # 1 and data for MS # 2 in RS # 2 are stored and transmitted.

Therefore, the two wireless terminals MS # 1 and MS # 2 receive DL-MAP from the wireless base station BS, respectively, and receive the bursts defined in the DL-MAP IE from the relay stations RS # 1 and RS # 2, respectively, and demodulate them. And decode and receive a data packet to which the CID in front of it is added. In this burst, data packets are simultaneously transmitted from different relay stations, but since these relay stations do not interfere with each other, each of the wireless terminals MS # 1 and MS # 2 can normally perform reception processing. The relay station RS needs to relay only data to the wireless terminal MS existing under management. In this way, the DL-MAP message indicates that data in front of the plurality of radio terminals MS exists, and in reality, each relay station RS transmits only data in front of the radio terminal MS under management.

6A and 6B are diagrams showing an example when communication is performed using the DL-MAP IE and the like shown in FIGS. 5A and 5B.

First, the radio base station BS transmits data to two relay stations RS # 1 and RS # 2 using different frequency channels at the same time (same symbol) (see Fig. 6A).

Next, each relay station RS # 1, RS # 2 transmits data to the wireless terminals MS # 1, MS # 2 under management simultaneously using a common frequency channel (subchannel) (see FIG. 6B). ).

In this way, the relay stations RS # 1 and RS # 2 that do not interfere with each other use the same radio resources when transmitting data to the wireless terminals MS # 1 and MS # 2 under their management, thereby improving the use efficiency of the band. You can.

In addition, in the burst of "RS # 1" in the subframe shown in FIG. 5B, the data transmitted from the radio base station BS to the relay station RS # 1 is converted to the burst immediately after "MS # 1, MS # 2". It is not necessary to transmit from the relay station RS # 1 to the radio terminal MS # 1. Data preceding the radio terminal devices MS # 1 and MS # 2 may be transmitted in advance to the relay stations RS # 1 and RS # 2 in the radio frame immediately before the radio frame. This is because the processing delays (processing delays for interpreting control messages such as DL-MAP) of the relay stations RS # 1 and RS # 2 are taken into account.

In addition, although the burst in front of the relay stations RS # 1 and RS # 2 shown in FIG. 5B is shown as being separately defined, the two relay stations RS # 1 and RS # 2 have the same modulation scheme. When communicating using the error correction coding method, it is also possible to define as one burst.

Next, a block configuration example of the relay station RS will be described with reference to FIG. 7.

The relay station RS includes a receiving unit 31, a control message extracting unit 32, a PDU buffer unit 33, a transmitting unit 34, a MAP information analyzing unit 35, and a control message generating unit 36. Equipped.

The receiver 31 outputs the uplink radio channel performance information measured by the signal from the radio terminal MS, and the radio channel performance information of the downlink fed back from the radio terminal MS to the control message generator 36, Other user data and control messages (DL-MAP messages, etc.) are output to the control message extraction unit 32.

The control message generating unit 36 generates a control message for transmitting the radio channel performance information from the receiving unit 31 to the radio base station BS, and accumulates in the PDU buffer unit 33. The accumulated control message is transmitted to the transmitter 34 for each frame and transmitted to the wireless terminal MS.

The control message extraction unit 32 outputs the control message to the MAP information analysis unit 35 and outputs the user data to the PDU buffer unit 33.

The MAP information analysis unit 35 analyzes a control message such as DL-MAP, and can receive transmission data (data transmitted via the MMR link) from the wireless base station BS based on the analysis result. The relay data (user data) stored in the PDU buffer unit 33 is transmitted to the wireless terminal MS under management.

In addition, as described above, in consideration of the processing delay for interpreting the DL-MAP, the relay data to the wireless terminal MS may be received in another control message immediately before the DL-MAP reception.

The receiver 31 receives only data for the radio terminal MS under the management of the relay station RS itself among the data transmitted from the radio base station BS, and discards other data. As described above, the DL-MAP message is assigned radio resources for a plurality of wireless terminal MSs in one burst. However, as for each relay station RS, only the wireless terminal MS under management transmits data. .

In the second embodiment, two wireless terminal MSs are defined in one burst, but of course, when there are three or more non-interfering relay stations RS, three or more wireless terminal MSs may be defined. It may be. Also in this case, since the same radio resource is allocated to each radio terminal MS, the use efficiency of the radio resource can be improved.

Third Embodiment

Next, a third embodiment will be described.

In this embodiment, the following examples are considered. 8 is a diagram illustrating a distribution example of the wireless terminal MS. As shown in Fig. 8, the wireless terminals MS # 1, MS # 2, MS # 3 are located at the cell edge of the relay station RS. It is assumed that relay stations RS # 1, RS # 2 and these wireless terminals MS # 1, MS # 2, MS # 3 communicate by QPSK. Since the wireless terminal MS # 4 is located in the vicinity of the relay station RS # 2, it is assumed that communication is performed by 16QAM which enables higher speed communication. The amount of data transmitted from each relay station RS to each radio terminal MS is assumed to be the same. At this time, the data in front of the wireless terminal MS # 4 can be transmitted in the radio resources (the number of subchannels) of half of other wireless terminal MSs. The relay stations RS # 1 and RS # 2 do not interfere with each other.

FIG. 9A is a diagram illustrating DL-MAP information and an example of data transmission in this case. Since the three wireless terminals MS # 1, MS # 2, and MS # 3 use a common QPSK communication scheme, MS # 3 uses the same transmission area as MS # 1 and / or MS # 2. Can be. In the figure, MS # 1 and MS # 3 use the same transmission area (same transmission timing, same transmission subchannel).

However, different radio resources are allocated to the wireless terminal MS # 4. In the figure, the transmission timing of MS # 4 is the same as the transmission timing of MS # 3. However, the transmission subchannel is a subchannel different from the transmission subchannel used by MS # 1, MS # 2, and MS # 3.

In this case, paying attention to the relay station RS # 1, since the wireless terminal MS # 4 is not the managed wireless terminal MS, it does not use the transmission area X assigned to the wireless terminal MS # 4. On the other hand, when attention is paid to relay station RS # 2, band Y other than the band allocated to wireless terminal MS # 3 is not used among the bands of QPSK.

Therefore, in the third embodiment, as shown in Fig. 9B, the wireless terminal MS # 4 is changed to communication by QPSK, thereby being used for the wireless terminal MS # 4 in Fig. 9A. The radio resource can be used by a radio base station BS (such as a radio terminal MS under the management of the radio base station BS) or another relay station RS, thereby improving the use efficiency of the radio resource.

10 shows a flowchart of the transmission area allocation process performed in the wireless base station BS. The radio frame configuration information generation unit 19 is processed. Processing from S21 to S26 is the same as the processing from S11 to S16 in FIG. 4. In a wireless terminal MS under non-interfering relay station RS management, the wireless terminal MSs are grouped by the same modulation scheme using the same error correction coding scheme.

In the radio resource unassignment, the same radio resource is allocated to the radio terminal MS of the modulation method and the error correction coding group having the lowest multivalue (S27). For example, in the case of QPSK, the multivalue is low, and in the case of 16QAM, the multivalue is high. In advance, it is possible to determine by holding in the radio base station BS a multi-value degree combining the modulation method and the error correction coding method and comparing them in the present processing. In the example of FIG. 9A, since the group of QPSK has the lowest multivalue, the radio resource is first assigned to the group of QPSK.

Next, it is determined whether the actual bandwidth usage difference between the relay stations RS is greater than or equal to the threshold value (S28). For example, in the above-described example, it is determined whether or not the difference "x-y" between the actual bandwidth usage "x" of the relay station RS # 1 and the actual bandwidth usage "y" of the relay station RS # 2 is equal to or greater than the threshold value. It is determined whether or not there is a band that can be used sufficiently.

If it is equal to or greater than the threshold (YES in S28), the same radio resource is allocated to the radio terminal unallocated radio terminal MS under the relay station RS management which has a low actual usage (S29). For example, in the above-described example, when the difference "xy" (area of band Y) can be sufficiently used, the same radio as that of the QPSK group is used for the radio terminal MS # 4 under the management of the relay station RS # 2 having a low actual usage. Allocate resources. An example of DL-MAP information when assigned is shown in FIG. 9B. In addition, MS # 4 employs QPSK as a communication method, although it has been determined that communication using QAM is possible by adaptive modulation control.

On the other hand, when it is not more than the threshold value (NO in S28), since there is no enough bandwidth available, the process proceeds to S30 without performing the process of S29.

Next, if there is a radio terminal unassigned radio resource (NO in S30), the process proceeds to S27 to repeat the process. If there is no unassigned wireless terminal MS (YES at S30), it is determined whether there is no unassigned band (S31). If there is an unassigned band (No in S31), the process proceeds to S22. If there is no unassigned band (Yes in S31), the creation of the DL-MAP is finished and transmitted.

Thereafter, the flow advances to S21 to repeat the above-described processing.

Of course, in order to be able to transmit data in the transmission area defined by DL-MAP, data is transmitted to the corresponding relay station RS from the radio base station BS to each radio terminal, and each relay station transmits data defined in the DL-MAP. Transmits data to the wireless terminal received from the wireless base station BS.

Fourth Example

Next, a fourth embodiment will be described.

In the third embodiment, a radio resource of a wireless terminal MS having a low multivalue is allocated to a wireless terminal MS having a high multivalue. In the fourth embodiment, on the contrary, it is an example of allocating a radio resource of the wireless terminal MS having a high multivalue to the wireless terminal MS having a low multivalue.

Consider the following example. 11 is a diagram illustrating a distribution example of the wireless terminal MS. As shown in Fig. 11, the wireless terminals MS # 1 and MS # 2 are located at the cell edge of the relay station RS # 1. It is assumed that these wireless terminals MS # 1 and MS # 2 communicate with QPSK.

On the other hand, the wireless terminals MS # 3 and MS # 4 are located near the relay station RS # 2. It is assumed that these wireless terminals MS # 3 and MS # 4 communicate with each other by 16QAM.

The amount of data to be transmitted to each wireless terminal MS is the same. Data in front of the wireless terminals MS # 3 and MS # 4 can be transmitted by half of the data in front of the wireless terminals MS # 1 and MS # 2.

At this time, if the processing according to the second embodiment is performed, as shown in Fig. 12A, the DL-MAP information includes a group of wireless terminals MS # 1 and MS # 2 that perform QPSK communication, Different radio resources are allocated to groups of the wireless terminals MS # 3 and MS # 4 that communicate with each other.

In the transmission of the relay station RS # 1, the band Z allocated to the radio terminals MS # 3 and MS # 4 is not used, and in the transmission of the relay station RS # 2, the band U allocated to the radio terminals MS # 1 and MS # 2 is Not used.

In the fourth embodiment, as shown in Fig. 12B, the wireless terminal MS # 3 of 16QAM communication having high multivalue is compared to the wireless terminals MS # 1 and MS # 2 of low QPSK communication. Allocates the same radio resource as MS # 4. Therefore, as in the third embodiment, the use efficiency of the radio resource can be improved. In addition, in FIG. 12A, the radio band used for the communication of the QPSK can be allocated to another relay station RS or a radio base station BS. From this point of view, the radio resource utilization efficiency can be improved.

In the fourth embodiment, however, the wireless terminals MS # 1 and MS # 2 are to increase their transmission power power in order to perform communication at 16QAM. This is to reliably communicate with the wireless terminals MS # 1 and MS # 2 located at the cell edge.

Fig. 13 is a diagram showing a flowchart of band allocation processing for the wireless terminal MS. This is a process executed by the radio frame configuration information generation unit 19. S41 to S46 are the same as S21 to S26 in FIG. 10. In a wireless terminal MS under non-interfering relay station RS management, wireless terminal MSs of the same FEC are grouped by the same modulation scheme.

In the radio resource unassignment, the same radio resource is allocated to the radio terminal MS of the modulation method and the FEC group having the highest multivalue (S47). In the example of FIG. 12B, the same radio resources are allocated to the wireless terminals MS # 3 and MS # 4.

Next, it is determined whether the actual bandwidth usage difference between the relay stations RS is equal to or greater than the threshold value (S48). As in the third embodiment, it is judged whether or not there is sufficient bandwidth.

If it is equal to or greater than the threshold value (YES in S48), the transmission power for the radio terminal unallocated radio terminal MS is increased under the relay station RS management with less actual usage, and the same radio resource is allocated (S49). In the above-described example, the same radio resources as those of the wireless terminals MS # 3 and MS # 4 are allocated to the wireless terminals MS # 1 and MS # 2. The relay station RS # 1 is instructed to increase the transmission power when communicating with the wireless terminals MS # 1 and MS # 2.

If the difference in the actual bandwidth usage is not greater than or equal to the threshold (No in S48), since the sufficient bandwidth is not secured, the process proceeds to S50 without performing the process of S49.

In S50, it is determined whether there is an unassigned radio terminal MS, and if there is no unassigned radio terminal MS (YES in S50), it is determined whether there is an unassigned band (S51). If there is an unassigned wireless terminal MS (NO in S50), the processing proceeds to S47.

If there is an unassigned band (YES in S51), the process proceeds to S41 and the above-described processing is repeated. If there is no unassigned band (NO in S51), the creation of DL-MAP is terminated and transmitted.

Thereafter, the flow advances to S41 and the above-described processing is repeated.

Of course, in order to be able to transmit data in the transmission area defined by DL-MAP, data is transmitted from the radio base station BS to each radio terminal to the corresponding relay station RS, and each relay station transmits data defined in the DL-MAP. In the area, data transmitted to the wireless terminal received from the wireless base station BS is transmitted.

Fig. 14 is a diagram showing a block configuration example of the radio base station BS in the fourth embodiment. What is different from the structure of the radio base station BS shown in FIG. 2 is that the relay station transmission power control information generation part 25 is added.

When the relay station transmission power control information generation unit 25 receives an instruction to increase the transmission power of the relay station RS from the radio frame configuration information generation unit 19, the control information for instructing the relay station RS to control information for increasing the transmission power. Create a message. The generated control information message is stored in the packet buffer unit 21 and transmitted by an instruction from the radio frame configuration information generation unit 19.

The power control for the relay station RS can also be performed by boosting information included in the DL-MAP IE (see FIG. 25).

Although the fourth embodiment has been described with respect to an example of increasing the transmission power with respect to the relay station RS, it is also possible to lower the transmission power and to adapt the high-value wireless terminal MS to a low modulation method and an error correction coding method. At this time, when the relay station transmission power control information generation unit 25 receives an instruction to lower the transmission power from the radio frame configuration information generation unit 19, the relay station transmission power control information generation unit 25 transmits control information for reducing the transmission power to the relay station RS.

In addition, as shown in FIG. 7, the relay station RS side interprets the control information for controlling the transmission power in the MAP information analysis unit 35, and instructs the transmission unit 34 to increase or decrease the transmission power. Based on that, the transmitter 34 adjusts the transmission power and data is transmitted to the wireless terminal MS.

Fifth Embodiment

Next, a fifth embodiment will be described.

In the fifth embodiment, this is an example of an uplink. By allocating the same transmission area to the radio terminal MS under the relay station RS management that does not interfere with each other, the use efficiency of radio resources and the use efficiency of frequencies are improved as in the second to fourth embodiments.

However, as described above, each burst by the UL-MAP message is defined by the number of slots as compared with the case by the DL-MAP message, and thus is not disposed at an absolute position, but is disposed at a relative position (Fig. 28 (A)). In addition, only one CID can be specified in the UL-MAP message. Therefore, it is impossible to arrange a plurality of wireless terminal MSs in one burst, and it is difficult to allocate a plurality of wireless terminal MSs in one uplink transmission area.

Therefore, in the fifth embodiment, at least part, preferably all, of the transmission area in the direction from the other relay station to the radio base station not interfering with the transmission area in the direction from the radio terminal MS to the relay station RS is overlapped.

In addition, allocation of a transmission area from the radio terminal MS to the relay station RS is performed by using a part of the UL-MAP message, and allocation of a transmission area from the relay station RS to the radio base station BS is performed by other parts of the UL-MAP message (particularly, RS-MAP). Is referred to).

For example, the allocation of a transmission area from each radio terminal MS to each relay station RS allocates a different transmission area (for example, a transmission time zone), and the allocation of a transmission area from each relay station RS to a radio base station is, respectively. Although different transmission areas (for example, transmission time zones) are allocated, the transmission area from the wireless terminal MS to the relay station RS # 1 and the relay station RS # 2 in a relationship not interfering with the relay station RS # 1 to the radio base station are transmitted. This allows for overlapping of regions.

By generating and transmitting such a UL-MAP message, a common radio band can be allocated to different transmission apparatuses as in the second embodiment and the like, and the efficiency of using the frequency can be improved.

Fig. 15 is a diagram showing a block configuration example of the radio base station BS in the fifth embodiment. Compared with the block diagram of the radio base station BS shown in FIG. 2, a control information extracting unit 26, a band request analyzing unit 27, and a relay station band allocation information generating unit 28 are added.

The control information extracting unit 26 extracts the band request (the band request from the relay station RS or the wireless terminal MS) from the receiving unit 11 and outputs it to the band request analyzing unit 27. The band request analysis unit 27 outputs the creation request information of the UL-MAP message corresponding to the band request to the radio frame configuration information generation unit 19.

The radio frame configuration information generation unit 19 creates a UL-MAP message based on this creation request. The information for creating the UL-MAP is obtained from the radio terminal communication path manager 15, the radio terminal communication method manager 17, and the non-interfering relay station manager 18, similarly to the second embodiment. At this time, the radio frame configuration information generation unit 19 outputs the information on the UL-MAP to the relay station band allocation information generation unit 28.

The relay station band allocation information generation unit 28, upon receiving the information on the UL-MAP, generates an RS-MAP message (relay station band allocation information) and transmits it to the relay station RS via the packet buffer unit 21 or the like.

FIG. 16A illustrates an example of an RS-MAP message, and FIG. 16B illustrates an example of a Burst Profile RS-MAP IE (hereinafter referred to as "RS-MAP IE") included in an RS-MAP message. . In the RS-MAP IE, similar to the DL-MAP IE (see Fig. 5A), the relay station RS targeted by the "CID" is designated, the burst is designated by the "Symbol Offset", and the radio resources are allocated. do. Of course, like the DL-MAP IE, a plurality of "CIDs" may be specified.

17A and 17B are diagrams showing the same transmission area in the same transmission subframe, respectively (MAP data is omitted).

As shown in these figures, the band allocation of the uplink (for relay station RS # 1) to the radio terminal MS # 1 under the management of the relay station RS # 1 is performed in the time zone of Zone # 1, and at the same time, the relay station RS # 1 Band allocation of the uplink (for the wireless base station BS) is performed for the relay station RS # 2 that does not interfere. Further, in the following Zone # 2, band allocation for transmission to the relay station RS2 for the radio terminal MS # 2 under the management of the relay station RS # 2 is performed, and for the relay station RS # 1 that does not interfere with the relay station RS # 2 at the same time. Band allocation for transmission to the wireless base station BS is performed. In addition, a UL-MAP message is created and transmitted so that radio resource allocation is performed in this way.

In addition, since the number of slots is defined in the UL-MAP message (see FIG. 27B), the burst shown in FIG. This can be assigned.

17C and 17D schematically show the communication status in each time zone. In Zone # 1, the radio terminal MS # 1 transmits data to the relay station RS # 1, and the relay station RS # 2 also transmits to the radio base station BS simultaneously using the same radio resource. In Zone # 2, relay station RS # 1 transmits data to wireless base station BS, and wireless terminal MS # 2 transmits data to relay station RS # 2 using the same radio resource at the same time. 18 is a flowchart of band allocation processing in the radio frame configuration information generation unit 19. The processing from S61 to S65 is the same as the processing from S11 to S15 in Fig. 4 which is the second embodiment.

Then, the radio frame configuration information generation unit 19 allocates a band to the radio terminal MS under each group management by using different time zones for each group (S66). In the above example, the same radio resource is allocated to the radio terminal MS # 1 and the relay station RS # 2, and the same radio resource is allocated to the radio terminal MS # 2 and the relay station RS # 1.

Next, if there is no unassigned band (YES in S67), MAP data indicating the allocated result is created and transmitted. Thereafter, the flow advances to S61 and the above-described processing is repeated.

If there is an unassigned band (NO in S67), the process proceeds to S62 and the above-described processing is repeated.

19 is a flowchart of processing in the relay station band allocation information generation unit 28 of the radio base station BS.

First, it is determined whether or not the information used for generating UL-MAP information has been received from the radio frame configuration information generation unit 19 (S71), and when received (Yes), under the control of another RS that does not interfere, The band in the time zone in which the band is allocated to the wireless terminal MS is allocated to the relay station RS (S72). In the above-described example, the band in the time zone Zone # 1 in which the band is allocated to the wireless terminal MS # 1 under the control of another relay station RS # 1 that does not interfere is allocated to the relay station RS # 2. Corresponds to the generation process of the RS-MAP message.

On the other hand, when the information is not received from the radio frame configuration information generation unit 19 (No in S71), it waits until the reception.

The fifth embodiment can be applied to the above-described third and fourth embodiments.

Sixth Example

Next, a sixth embodiment will be described.

In the second embodiment, a plurality of CIDs are designated in the DL-MAP IE (FIG. 5A), and the same transmission area is allocated to the plurality of wireless terminal MSs. In the sixth embodiment, one CID is designated to one DL-MAP IE, the "Symbol Offset" of each DL-MAP IE is the same, and "DIUC" is specified to a different value. As a result, the same transmission area is allocated to each wireless terminal MS, and the modulation scheme, coding scheme, and coding rate can be specified differently.

By differentiating the modulation scheme from the relay station RS to the wireless terminal MS under management that does not interfere with each other, it is possible to transmit data adapted to the position of the wireless terminal MS in the cell. Of course, since the same transmission area is allocated to each wireless terminal MS, it is possible to improve the efficiency of using the frequency.

20 is a diagram showing a flowchart of processing in the radio frame configuration information generation unit 19 according to the sixth embodiment. The processing from S81 to S84 is the same as the processing from S11 to S14 in the second embodiment (Fig. 4).

In the processing of S85, the non-interfering relay station management table T3 is searched for, the wireless terminal MS under the non-interfering relay station RS management is extracted, and grouped for each relay station RS to be connected. Similarly to the second embodiment, when the wireless terminal MS shown in Fig. 6A is distributed, the wireless terminal MS # 1 and the wireless terminal MS # 2 are grouped separately.

Next, a band is allocated to the wireless terminal MS for each group by using the same transmission area (S86). In the above example, the band is allocated to the wireless terminal MS # 1 and the wireless terminal MS # 2 using the same transmission area.

Next, the same processing as in S18 of the second embodiment is performed (S87).

21A and 21B are diagrams showing an example of allocation of DL-MAP. Two wireless terminals MS # 1 and MS # 2 are assigned to the same burst.

Examples of downlink transmissions in this case are shown in Figs. 21C and 21D. Data is transmitted from the radio base station BS to the relay stations RS # 1 and RS # 2 that do not interfere with each other at the same time, and the same time to the radio terminals MS # 1 and MS # 2 under the management of each relay station RS # 1 and RS # 2. The data is transmitted by different modulation schemes.

In the sixth embodiment, the downlink has been described, but the same can be applied to the uplink. In addition, the sixth embodiment can also be applied to the third and fourth embodiments. Either one can be assigned to the wireless terminal MS under the management of the relay station RS that does not interfere with the same transmission area, and data can be transmitted to the wireless terminal MS by different modulation schemes or the like.

In addition, in any of the above-described embodiments, although the transmission areas are shared between different transmission devices, the transmission areas to be shared do not have to be completely matched. For example, some transmission regions may be overlaid in time, or some transmission subchannels may be overlaid.

Preferably, the transmission start timings of the transmission areas are matched, and the transmission end timings may be allowed to be different between transmission devices.

Claims (15)

A wireless base station for transmitting data to and from a wireless terminal under management of each relay station through a plurality of relay stations under management, Some or all of the first transmission area from the first relay station to the first wireless terminal under management of the first relay station, and the second transmission area from the second relay station to the second wireless terminal under management of the second relay station A map information generation unit for generating map information indicating a radio frame configuration so as to overlap; Transmitter for transmitting the map information Wireless base station comprising a. The method of claim 1, The overlapping transmission area is a radio base station, characterized in that the frequency channel. The method of claim 1, And the first relay station and the second relay station are arranged at positions not interfering with each other. The method of claim 1, A wireless base station, wherein the same modulation scheme and coding scheme are used for the portion where the duplication occurs. The method of claim 1, The control unit may further include: when the modulation scheme and encoding scheme of the first wireless terminal and the modulation scheme and encoding scheme of the second wireless terminal are different from each other by adaptive modulation control, And specifying an encoding scheme to match the modulation scheme and the encoding scheme of the second wireless terminal. The method of claim 1, And the control unit generates control information for changing transmission power when transmitting the first data from the first relay station to the first radio terminal, and transmits the control information to the first relay station. The method of claim 1, And the control unit separately specifies the modulation scheme and encoding scheme of the first wireless terminal and the modulation scheme and encoding scheme of the second wireless terminal from the map information. A relay station for relaying data between a wireless terminal under management and a wireless base station, The first data in front of the radio terminal under the management and another relay station different from the relay station transmit the first data in a transmission area where some or all of the second data in front of the second radio terminal under the other relay station overlaps. Control unit The relay station comprising a. A wireless base station for transmitting data between a first terminal and a second relay station under management, with a wireless terminal under management of the first and second relay stations, The second radio terminal under the management of the second relay station from the first relay station to the first radio terminal under the management of the first relay station, and to the map information defining one transmission area. A map information generation unit defining a transmission to Transmitter for transmitting the map information Wireless base station comprising a. As a relay station for relaying data between a wireless terminal under management and a wireless base station, A receiving unit which receives map information in which first and second transmission areas in which all or part overlap with each other are defined; Transmitter that transmits data to the wireless terminal under the management in the first transmission area, but does not transmit the data to the wireless terminal under the management of another relay station in the second transmission area. Relay station, characterized in that provided with. A relay station for relaying data between a first wireless terminal under management and a wireless base station, A first wireless terminal under management of the relay station in a transmission area in which part or all overlap with a transmission area in which another relay station under management of the wireless base station transmits data from a second wireless terminal under management of the other relay station to the wireless base station; Control to control receiving data from The relay station comprising a. A relay station for relaying data between a first wireless terminal under management and a wireless base station, The data from the first wireless terminal under the control of the relay station is stored in a transmission area in which part or all overlap with the transmission area in which data is transmitted from the second wireless terminal under management of the radio base station to the other relay station. Control unit to control transmission to the wireless base station The relay station comprising a. A wireless base station for receiving data from each wireless terminal under management of each relay station through a plurality of relay stations under management, Some or all of the first transmission area allocated to the first wireless terminal under the management of the first relay station and the second transmission area allocated to the second relay station or, A part or all of the third transmission area allocated to the first relay station and the fourth transmission area allocated to the second wireless terminal under management of the second relay station are overlapped and defined. A map information generator for generating map information, A transmitter for transmitting the first map information and the second map information Wireless base station comprising a. A communication control method in a wireless communication system in which data is transmitted between a radio base station and a radio base station under management of each relay station through a plurality of relay stations under management. Transmitting first data to a first wireless terminal under management of a first relay station and second data to a second wireless terminal under management of a second relay station from the wireless base station to the first relay station and the second relay station, respectively, Transmitting the first data and the second data from the first relay station and the second relay station so that a transmission area overlaps with some or all of them; Communication control method, characterized in that. A communication control method in a wireless communication system in which data is transmitted between a radio base station and a radio base station under management of each relay station through a plurality of relay stations under management. And transmitting the first data from the first wireless terminal under the control of the first relay station and the second data from the second relay station in a transmission area in which part or all overlap.

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