JP5252034B2 - Relay station, radio base station, and communication method - Google Patents

Description

The present invention relates to a relay station, a radio base station, and a communication method using radio communication, for example, IE.
It is particularly suitable for use when adding a relay station based on a wireless communication system defined in EE 802.16.

Currently, wireless communication systems that perform communication via wireless communication paths are widely used worldwide, with systems such as WCDMA and CDMA2000 being representative. In such a radio communication system, a plurality of radio base stations are installed for a service area, and a radio terminal communicates with another communication device (communication terminal) via any one of the radio base stations. At this time, an overlapping portion is provided in a service area in which adjacent radio base stations can perform radio communication, and a radio terminal can be handed over to an adjacent radio base station as the radio environment deteriorates.

In addition, as a radio system, for example, code division multiplexing, time division multiplexing, frequency multiplexing, OFDM,
In general, a plurality of wireless terminals can be connected to one wireless base station at the same time.

However, even in a service area where the wireless base station can perform wireless communication, high-speed communication is often difficult at locations close to the boundary of the area due to poor wireless environment.

Therefore, a proposal has been proposed in which a relay station is arranged in the service area of the radio base station so that the radio terminal and the radio base station can perform radio communication via the relay station.

In particular, in the 802.16j task group, such a relay station (RS: Rela
The introduction of y Station) is currently under consideration.

The above-described matters relating to IEEE 802.16 are disclosed in, for example, the following non-patent documents 1 and 2.
IEEE Std802.16TM-2004 IEEE Std802.16eTM-2005

According to the background art described above, a wireless terminal can perform wireless communication with a wireless base station directly or via a relay station, but the relay station is interposed between the wireless base station and the wireless terminal. The transmission and reception of the wireless terminal cannot be controlled simply by transferring the signal.

Accordingly, one of the objects of the present invention is to enable a relay station to control communication between the relay station and a wireless terminal.

In addition, the present invention is not limited to the above object, and other effects of the present invention can be obtained by the respective configurations shown in the best mode for carrying out the invention described below, and cannot be obtained by conventional techniques. It can be positioned as one of

In the present invention, receives the first control signal from the radio base station a first control signal sent directly to the wireless terminal for controlling the receiving operation in the no line terminal, wireless accordance first control signal to the wireless terminal In the relay station that transmits a signal, a determination unit that determines whether it is necessary to control the reception operation in the wireless terminal based on the reception status from the wireless base station or the wireless terminal, and based on the determination generates a second control signal which the relay station controls the reception operation of the wireless terminal transmits to the wireless base station, the first generated by the radio base station based on said second control signal a transmitting unit that transmits radio signals to the control signal thus against the wireless terminal, using a relay station, comprising the.

In the present invention, directly transmit a first control signal for controlling the reception operation of the wireless terminal to the wireless terminal, the relay station radio signals to the radio terminals under the control of receiving operation by said first control signal in the radio base station transmitting through, from the relay station to determine based on whether or not it is necessary to control the receiving operation in the wireless terminal with a reception status from the wireless base station or wireless terminal, the relay station generates a reception processing unit a signal for controlling the reception operation of the wireless terminal receiving the second control signal based on the determination, the first control signal based on said second control signal, transmitted A radio base station characterized by including a transmission processing unit is used.

In the present invention, it receives the first control signal from the radio base station a first control signal sent directly to the wireless terminal that controls the reception operation of the wireless terminal, included in the radio signal received from the radio base station a relay station for transmitting data to said first control signal to thus wireless terminal, when an error is detected in the received said data, the determination unit to determine that it is necessary to control the receiving operation of the wireless terminal And a transmission processing unit that generates a second control signal indicating that an error in the data has been detected based on the determination result of the determination unit and transmits the second control signal to the radio base station, and the data from the radio base station and a reception processing section for receiving data relating to the retransmission, the transmission processing unit, the wireless terminal operating in accordance with the first control signal generated by the radio base station based on said second control signal In contrast, a feature to transmit to said first control signal generated by the radio base station based on the second control signal therefore a radio signal to the wireless terminal including the data relating to feed該再received Use a relay station.

In the present invention, it receives the first control signal from the radio base station a first control signal sent directly to the wireless terminal that controls the reception operation of the wireless terminal, included in the radio signal received from the radio base station In a relay station that transmits data to the wireless terminal according to the first control signal ,
A storage unit for storing the data received from the radio base station, an error is not detected for the data received from the radio base station, indicating that detects Ri erroneous for the data from the wireless terminal which has received the data When the signal is received, a determination unit that determines that the reception operation in the wireless terminal needs to be controlled, and an error in the data is detected in the wireless terminal based on a determination result of the determination unit It generates a second control signal indicating that a transmission processing section that transmits to the wireless base station, the transmission processing unit, the first generated by the radio base station based on said second control signal against wireless terminal operating in accordance with the control signal, it generates a retransmission data with the data stored in the storage unit, the first control signal generated by the radio base station based on the second control signal follow the Te, using relay station and transmitting a radio signal containing the retransmitted data to the wireless terminal.

In the present invention, a first control signal for controlling a reception operation in a wireless terminal is directly transmitted to the wireless terminal, and data included in the wireless signal is transmitted to the wireless terminal via a relay station according to the first control signal. Generated when an error is detected in the data received by the relay station and a transmission processing unit for transmitting a radio signal including data to be transmitted to the radio terminal in accordance with the first control signal in the transmitting radio base station It is a reception processing unit for the second control signal transmitted received from the relay station, the transmission processing unit, the wireless terminal operating in accordance with the first control signal generated based on the second control signal features respect, via the relay station, a radio signal containing data relating to the retransmission of the data, and Turkey be transmitted in accordance with the first control signal generated based on the second control signal Using a radio base station.

In the present invention, a first control signal for controlling a reception operation in a wireless terminal is directly transmitted to the wireless terminal, and data included in the wireless signal is transmitted to the wireless terminal via a relay station according to the first control signal. In the transmitting radio base station, a transmission processing unit that transmits a radio signal including data to be transmitted to the radio terminal according to the first control signal, and no error is detected in the data received at the relay station, and the radio the second control signal is generated and sent when an error is detected for the data received at the terminal and a reception processing unit for receiving from the relay station, the transmission processing section, based on said second control signal It generates and transmits the first control signal Te, but for data related to retransmission of said data transmission to the relay station uses a radio base station, wherein the go, such performed.

According to the present invention, the relay station can control communication between the relay station and the wireless terminal.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[A] Description of First Embodiment It is necessary to establish synchronization when a wireless terminal receives a signal from a wireless base station by wireless. Therefore, each radio base station transmits a signal for synchronization within the service area of the own station. For example, a signal (synchronization signal) for the synchronization can be a preamble signal different in each radio base station. The wireless terminal stores a plurality of types of preamble signal patterns in advance, and can select a pattern having the best reception quality (for example, reception level) from among the patterns as a communication destination wireless base station.

As a radio scheme, for example, when using OFDM, a radio base station allocates transmission data to each subcarrier and performs transmission using a plurality of subcarriers. A preamble is transmitted to each subcarrier in a predetermined pattern. Can be allocated and sent. The wireless terminal can synchronize with the wireless base station that receives the predetermined combination of subcarriers, matches the known preamble signal, and transmits the best preamble.

Further, the radio base station configures a frame based on the synchronization signal and transmits the signal. The wireless terminal establishes frame synchronization using the synchronization signal, and data mapping (radio frame structure) information (data for controlling the transmission or reception operation of the wireless terminal on the basis of the synchronization signal; MAP;
Data). For example, MAP data is arranged immediately after the synchronization signal.

In MAP data, timing when mapping data to physical channels (down channel (channel from the radio base station to the radio terminal side), uplink channel (channel from the radio terminal side to the radio base station side)), channel information Modulation scheme, encoding scheme, encoding rate, etc., and the radio frame has a structure corresponding to MAP data. Furthermore, a physical channel can be designated for each wireless terminal by designating the wireless terminal using the identification information of the terminal. Of course, mapping information is transmitted to a plurality of wireless terminals (for example, all wireless terminals in a service area formed by one wireless base station) for transmission / reception of a predetermined signal without specially specifying the wireless terminal. You can also.

Therefore, data configured by associating parameters necessary for reception (transmission) such as reception (transmission) timing, reception (transmission) channel (reception (transmission) subchannel pattern information) with the terminal ID is an example of MAP data. Can be used as

The wireless terminal receives a radio signal through the reception timing and reception channel specified by the MAP data, and transmits the radio signal through the transmission timing and transmission channel specified by the MAP data. As a result, wireless communication can be performed directly (without going through a relay station) with the wireless base station.

On the other hand, the relay station similarly receives the synchronization signal from the radio base station and establishes synchronization. Then, MAP data is received with reference to the synchronization signal, and transmission data to the wireless terminal is transmitted according to parameters necessary for transmission such as transmission timing and transmission channel (transmission subchannel pattern information) specified by the MAP data. . Note that transmission data to the wireless terminal can be acquired using a communication link (MMR link) between the wireless base station and the relay station. Note that the relay station can also acquire in advance parameters such as transmission timing and channel designated by the MAP data using the MMR link.

That is, the relay station receives a radio signal addressed to itself through the reception timing and reception channel specified by the MAP data or the MMR link, and transmits a radio signal to be transmitted from the local station through the transmission timing and transmission channel specified by the MAP data. Send a signal. The MMR link is communication between the radio base station and the relay station, and the radio terminal does not need to receive it.

For MAP data, the relay station does not retransmit to the wireless terminal. This is because the MAP data is likely to reach the wireless terminal with respect to the transmission data by increasing the transmission power only at that portion or transmitting at a low speed with respect to the general transmission data (user data). It is.

The wireless terminal can receive the transmission data retransmitted from the relay station by receiving the MAP data directly from the wireless base station and receiving the wireless signal accordingly.

Accordingly, the radio terminal can directly receive data from the radio base station, and can also receive data once received from the radio base station by the relay station from the relay station.

The wireless terminal only receives and transmits according to the MAP data transmitted from the wireless base station, and does not need to recognize that data is transmitted / received via the relay station.

As described above, by using the relay station, a plurality of wireless terminal transmission / reception path candidates are provided, and wireless communication of the wireless terminal near the boundary of the service area of the wireless base station can be supported.

Here, it is desirable that the relay station does not transfer (transmit) the synchronization signal periodically transmitted from the radio base station to the radio terminal. That is, if the relay station transmits a synchronization signal, the wireless terminal receives the synchronization signal from the relay station, synchronizes with the relay station, and searches for MAP data based on the synchronization signal, but does not find it. This is because. In addition, it becomes necessary to recognize the existence of a separate station different from the radio base station.

As described above, when the MAP data is not transmitted from the relay station to the wireless terminal, there is no means for controlling the transmission / reception operation of the wireless terminal from the relay station.

Therefore, the relay station transmits a signal for controlling the transmission / reception operation of the wireless terminal to the wireless base station.

  Hereinafter, the detailed configuration and operation of each part will be described with reference to the drawings.

FIG. 1 shows the configuration of a wireless communication system in the first embodiment. In the figure, 1 is a routing device, 2 is a radio base station (BS), 3 is a relay station (RS), and 4 is a radio terminal (T). The wireless terminal 4 is a so-called MS (Mobile) suitable for mobile use.
Station) or any wireless device suitable for fixed use can be used.

Here, the wireless terminal 4 can perform wireless communication directly with the wireless base station 2 within the service area of the wireless base station 2 (without passing through the relay station), or within the service area of the relay station 3. Wireless communication with the wireless base station 2 can also be performed via the relay station 3. The relay station 3 is the radio base station 2
One or more service areas are provided, and can perform wireless communication with the wireless terminal 4.

The radio base station 2 is connected to the routing device 1, receives data from the radio terminal 4, sends the data to the routing device 1, and conversely sends the data received from the routing device 1 to the radio terminal 4. Control to send. The routing device 1 is connected to a plurality of radio base stations, and sends the data received from the radio base station 2 to another routing device or another radio base station, thereby performing routing so that the data reaches the transmission destination. Do.
Preferably, the radio base station 2 converts the data into a packet format and then transfers the data to the routing device. A database storing the location registration area of the wireless terminal (information on the location of the wireless terminal in each area composed of a plurality of wireless base stations), the service form, etc. is arranged so that it can be accessed from the routing device 1. It is desirable that the routing device can acquire these pieces of information as necessary during routing.

  Next, the configuration of the radio base station 2 will be described in more detail with reference to FIG.

  FIG. 2 is a diagram showing the configuration of the radio base station 2.

In the figure, 10 is an antenna for transmitting and receiving a radio signal between the relay station 3 and the wireless terminal 4, 11 is a duplexer for sharing the antenna 10 in a transmission and reception system, 12 is a receiving unit, 13
Is a demodulator for demodulating the received signal, 14 is a decoder for decoding the demodulated received signal, 15 is for extracting control data from the decoded data and transferring it to the communication path determining unit 17, and for other data such as user data A control data extraction unit 16 for transferring to the packet generation unit 16 and a packet generation unit 16 for packetizing the data transferred from the control data extraction unit and delivering it to the NW interface unit.

Reference numeral 17 denotes an interface unit that forms an interface with the routing apparatus 1 (here, packet communication is performed), and 18 identifies an IP address included in the packet data received from the NW interface unit 20. The destination wireless terminal 4 is identified based on the address data (for example, the correspondence between the IP address data and the ID of the wireless terminal 4 is stored and the ID of the corresponding wireless terminal 4 is acquired), and the QOS corresponding to the ID (similarly I
Information is stored in correspondence with D), ID and QOS information is given to the MAP information generation unit 24, a bandwidth allocation request is made, and the packet data passed from the NW interface unit 17 is sent to the packet buffer unit 19. Store.

Reference numeral 24 denotes a MAP information generation unit. When a bandwidth allocation request is received, a communication path is specified by searching using the ID of the wireless terminal 4 as a key, a mapping area corresponding to the QOS is determined, and a frame according to it is determined. The PDU generation unit 24 is instructed to configure. At that time, the data to be transmitted is read from the packet buffer unit 19 and the PDU generation unit 2 together with the MAP data.
Deliver to 0. Since a communication link (MMR link) is also provided between the radio base station 2 and the relay station 3, the identification information of the relay station 3 to be communicated, the transmission / reception timing,
Data can also be transmitted to the relay station at the corresponding timing and channel including the channel.

Further, the MAP information generation unit 24 generates MAP data based on a control signal from the relay station 3 according to an instruction from the control unit 25. For example, UL MAP that defines upstream communication
DL that generates data based on a control signal from the relay station 3 or defines downlink communication
MAP data is generated based on a control signal from the relay station 3.

Reference numeral 20 denotes a PDU generator, which generates a PDU so that MAP data, transmission data (including measurement control data), etc. are stored in each area of a radio frame formed with reference to a synchronization signal (preamble). To the conversion unit 21. Reference numeral 21 denotes an encoding unit, 22 denotes a modulation unit, and 23 denotes a transmission unit. The PDU data is subjected to encoding processing such as error correction encoding in order, and then modulated, and a radio signal is transmitted from the transmission unit 23 via the antenna 10. Send as.

Reference numeral 25 denotes a control unit, which controls the transmission processing unit and the reception processing unit to control the transmission / reception operation, acquires control data from the relay station 3 extracted by the control data extraction unit 15, and based on the control data The MAP data generation unit 24 is instructed to generate MAP data.

  FIG. 3 is a diagram illustrating the configuration of the relay station 3.

In the figure, 30 is an antenna for transmitting and receiving radio signals between the radio base station 2 and the radio terminal 4, 31 is a duplexer for sharing the antenna 10 for transmission and reception, 32 is a receiving unit, 3
3 is a demodulator that demodulates the received signal, 34 is a decoder that decodes the demodulated received signal, and 35 is a MAP information analyzer 36 that extracts MAP data (received from the radio base station 2) from the decoded data.
And a control data extraction unit 35 that transfers data addressed to the wireless terminal 4 received from the wireless base station 2 to the PDU buffer unit 37. Similarly, when a radio signal is received from the radio terminal 4, the received data is transferred to the PDU buffer unit 37 for transmission to the radio base station 2.

Reference numeral 37 denotes a PDU buffer unit, and the MAP data or M analyzed by the MAP information analysis unit 36
Based on the data received via the MR link, the stored data is transmitted so that the corresponding data addressed to the radio terminal 4 received from the radio base station 2 is transmitted according to the transmission timing and channel notified by the radio base station 2. Delivered to the encoding unit. Note that data addressed to the wireless terminal 4 is received via a communication link (MMR link) formed between the wireless base station 2 and the relay station 3.
In addition, since the MAP data transmitted from the radio base station 2 includes the identification information of the relay station 3, the transmission timing, and information on the channel, the relay station 3 receives the signal at the designated timing and channel. Transmission of data or the like is executed between the radio base station 2 and the relay station 3 (the uplink direction is similarly defined by MAP data).

Reference numeral 38 denotes an encoding unit, and 39 denotes a modulation unit, which encodes transmission data from the PDU buffer unit 37 and performs modulation processing so that user data is transmitted on the transmission timing and channel acquired by the MAP information analysis unit 36. And then hand it over to the transmitter 40.

Reference numeral 40 denotes a transmission unit which transmits a transmission signal as a radio signal to the radio terminal 4 and the radio base station 2 via the antenna 30.

Reference numeral 41 denotes a control unit, and the relay station 3 and the wireless terminal 4 according to the reception status in the reception processing unit.
When it is determined that control is necessary for communication with the mobile station, a control signal (data) corresponding to the control is generated and transmitted so as to be transmitted to the radio base station 2 via the MMR link. Control the processing unit. That is, the control unit 25 of the radio base station 2 and the control unit 41 of the relay station 3
It is possible to transmit / receive control signals to / from each other via a link.

The control unit 41 controls the transmission processing unit and the reception processing unit so that transmission / reception is performed at the transmission / reception timing acquired by the MAP information analysis unit 36.

  FIG. 4 is a diagram showing the configuration of the wireless terminal 4.

In the figure, 50 is an antenna for transmitting and receiving radio signals between the relay station 3 and the radio base station 2, 51 is a duplexer for sharing the antenna 50 for transmission and reception, 52 is a receiver, 53
Is a demodulator for demodulating the received signal, 54 is a decoder for decoding the demodulated received signal, 55 is extracting control data from the decoded data, and if it is MAP data, it is supplied to the MAP information analyzer 58 and other data (user Data) to the data processing unit 56. Reference numeral 56 denotes a data processing unit, which performs display processing of various data included in received data, audio output processing, and the like.

Further, user data desired to be transmitted from the data processing unit 56 to the communication destination device is:
The data is input to the PDU buffer unit 57.

Reference numeral 57 denotes a PDU buffer unit, which outputs data stored in the encoding unit 59 so that transmission data from the data processing unit 56 can be transmitted by the transmission timing and transmission channel specified by the MAP data.

Reference numeral 58 denotes a MAP information analysis unit, which analyzes MAP data received directly from the radio base station 2 and gives an analysis result to the control unit 62. That is, the transmission / reception timing of various data is notified to the control unit 62.

59 denotes an encoding unit, 60 denotes a modulation unit, and transmission data from the PDU buffer unit 57 is converted into MA.
The transmission data is encoded and modulated under the control of the control unit 62 so that transmission is performed using the transmission timing and transmission channel specified by the P information.

  The transmission unit 61 transmits a radio signal via the antenna 50.

  The control unit 62 controls operations of the transmission processing unit and the reception processing unit based on the MAP data.

Next, an example of a radio frame format is presented, and a communication procedure in the system is described in detail. Here, a radio frame format corresponding to IEEE Std 802.16d, e is taken as an example, but the embodiment is not limited to this.

FIG. 5 is a diagram illustrating an example of a frame format of a radio signal transmitted / received between a radio base station, a relay station, and a radio terminal. It is assumed that BS2-1, RS3-1, T4-1, and T4-3 have the arrangement relationship shown in FIG.

In the figure, Tx and Rx mean transmission and reception, respectively. Therefore, B2 uses DL / UL MAP, MMR1 (relay station 3-1) with preamble (P) as the head of the frame.
Send / receive data to and from The preamble is a predetermined known pattern that is transmitted to enable the radio terminal 4 and the relay station 3 to synchronize with the radio base station 2, and O
When FDM is used, a predetermined pattern signal is transmitted through each subchannel.

Following the preamble transmission is DL / UL MAP, which is an area for storing control data (MAP data) for notifying the relay station 3 and the wireless terminal 4 about the transmission reception timing and transmission / reception channel. . For example, the transmission timing and transmission channel information of MMR1 transmitted as a MMR link from the radio base station to the relay station via the downlink channel, and data transmission (T4-1, T4-) to the radio terminals 4-1 and 4-3. 3) timing and transmission channel information, and MAP data (radio frame structure information) indicating information indicating at which timing and in which channel data (MMR1, T4-1, T4-3) should be transmitted via the uplink channel )including.

Therefore, each relay station 3 and the wireless terminals 4 (4-1, 4-3) receive the preamble P directly from the wireless base station 2 to synchronize with the frame timing of the wireless base station 2 and use the DL as a reference. / UL MAP is received, the timing and channel to be transmitted / received are grasped, and transmission / reception is performed at the corresponding timing and channel.

In the example of the figure, the wireless terminal 4-3 can directly receive T4-3 from the wireless base station 2 and directly transmit T4-3 to the wireless base station 2.

However, the wireless terminal 4-1 cannot directly receive T 4-1 from the wireless base station 2 and directly transmit T 4-1 to the wireless base station 2.

Therefore, the RS 3-1 analyzes the DL / UL MAP and receives the MMR 1 including the message addressed to itself, thereby transmitting the data to be transmitted to the wireless terminal 4-1 by the transmission of T 4-1. Receive from. Similarly, the wireless terminal 4 designated by the DL / UL MAP
It is understood that the transmission timing of data to -1 is T4-1 in the figure, and the data received by MMR1 is transmitted at the timing of T4-1.

On the other hand, the wireless terminal 4-1 uses the preamble transmitted from the wireless base station 2 to transmit the wireless base station 2.
And the DL / UL MAP is analyzed, and the specified timing (T
4-1) Since it recognizes that data is transmitted on the channel, it operates to receive the data transferred from the relay station 3 by the timing and channel.

Accordingly, the wireless terminal 4 can receive data without being aware of the data transmission source (without distinguishing whether it is the wireless base station 2 or the RS 3).

The RNG is a ranging (Rangi) transmitted from the wireless terminal (T4-1, 4-3).
ng) signal. The Ranging signal is a known signal and is received by the radio base station 2 or the relay station 3, and the reception processing unit obtains reception timing shift (phase shift), reception frequency shift, and necessary transmission power increase / decrease information. Is reported to the radio base station 2. In this example, the RNG from the radio terminal 4-3 is directly received in the RNG reception period of the radio base station 2, and the RNG from the radio terminal 4-1 is received from the RNG reception period of the relay station 3 (of the radio base station 2). The same as the RNG reception period). Wireless terminal 4-1 received by relay station 3
Are transferred to the radio base station 2 through the uplink MMR link indicated by MMR1.
At that time, the adjustment information is generated by the relay station 3 and added to the RNG to be given to the radio base station 2.

The CQI indicates a transmission period for reporting a result of measurement of reception quality by a radio terminal for a known signal such as a preamble or a pilot signal. The radio base station 2 receives the received CQI
Based on the above, the transmission processing unit is controlled to change the transmission parameters such as the modulation scheme, the coding scheme, and the coding rate. The CQI is also transferred to the radio base station 2 through the uplink MMR link indicated by MMR1.

Transmission control of signals transmitted in the uplink direction such as RNG and CQI is performed using MAP data. For example, the timing at which RNG and CQI transmission is permitted by MAP data is set in a short cycle or in a long cycle. For example, when the transmission allowable period of RNG and CQI is provided once (defined) in one transmission of M transmissions of MAP data, the value of M is switched. In addition, RNG and CQI can individually specify the transmission timing and channel for each wireless terminal 4, and can also specify the transmission timing and channel for a plurality of wireless terminals 4. In the example, a period in which transmission is performed from BS2 to RS and T, a period in which transmission is performed from BS2 to RS (MMR period), a period in which transmission is performed from RS3-1 to T, RS3- The period during which transmission from 2 to T is performed is separated in time. Furthermore, the upstream direction is also temporally separated from the downstream direction, and similarly T, RS
The transmission periods are also separated in time. In this case, transmission and reception in each section are separated by time division (the same frequency band can be used), but other separation methods such as frequency separation can also be adopted.

Next, communication control between the relay station 3 and the wireless terminal 4 (4-1) when this frame configuration is used will be described.

First, the reception processing unit of the wireless terminal 4-1 receives the preamble transmitted from the wireless base station 2, synchronizes with the wireless frame transmitted from the wireless base station 2, and receives MAP data based on the preamble. Do. The MAP data is analyzed by the MAP data information analysis unit 58 and the analysis result is given to the control unit 62. Therefore, the control unit 62 grasps the transmission / reception timing of each data designated by the MAP data, and controls the transmission processing unit and the reception processing unit to operate according to the designated timing.

On the other hand, the reception processing unit of the relay station 3 also receives the preamble transmitted from the radio base station 2 to synchronize with the radio frame transmitted from the radio base station 2, and receives MAP data based on the preamble. The data addressed to the wireless terminal 4-1 is received via the MMR link, and the data received via the MMR link is transmitted to the wireless terminal 4-1 at the transmission timing designated by the wireless terminal 4-1 using the MAP data. Send to

Now, the MAP information analysis unit 36 of the relay station 3 interprets the MAP data (UL MAP),
In order to give the control unit 41 the uplink transmission timing specified by the MAP data, the control unit 62 receives the radio signal transmitted from the radio terminal 4-1 by controlling the reception processing unit according to the timing. be able to.

However, since the radio signal from the radio terminal 4 is transmitted according to the MAP data of the radio base station 2, the relay station 3 cannot control the transmission.

Therefore, if the control unit 41 of the relay station 3 determines that it is necessary to control the transmission operation of the subordinate radio terminal 4 (4-1), the control unit 41 generates contents to be reflected in the MAP data as a control signal. Then, the data is transmitted to the radio base station 2 via the MMR link via the transmission processing unit.

As the control signal, for example, a signal affecting the signal for controlling the CQI transmission operation in the wireless terminal 4 (4-1) can be considered. Specifically, the control unit 41 generates the control signal (CQI transmission control signal) illustrated in FIG. 7 and transmits it to the radio base station 2.

In the figure, MS Basic CID indicates identification information of a target wireless terminal for which transmission operation is to be controlled. Note that it is possible to designate a general unrelated terminal as a target, or to designate all wireless terminals as targets, and not to designate one wireless terminal specially.

Period indicates a cycle in which a specific signal is transmitted, and M can be specified as described above.

Frame Offset designates the timing for starting transmission by the current control, and designates how much the frame is delayed from the frame number of the radio frame being transmitted as a frame offset. It can also be the starting frame number itself.

Duration indicates a period during which the current control is valid. For example, N of the radio frame
Can be instructed to do so.

The Report Configuration is for instructing information to be transmitted to the wireless terminal 4 and an internal operation of the wireless terminal 4. For example, the type of data to be transmitted can be designated,
If it is CQI information to be transmitted to the wireless terminal 4, it is possible to specify for which signal the reception quality is measured and what type of CQI information is to be transmitted.

When the control unit 25 of the radio base station 2 receives the control signal from the relay station 3, the MAP information generation unit 24 reflects the contents of the control signal in MAP data to be transmitted thereafter.
To instruct. Preferably, all the request contents of the relay station 3 are reflected, but there are cases where it is difficult to reflect all the contents on the schedule. Therefore, it is preferable to reflect in the MAP data as much as possible.

For example, the frequency with which transmission is permitted to the wireless terminal 4 (only 4-1 in some cases) is increased by MAP data. In other words, data that allows the wireless terminal 4 to transmit data is set only once for M times of MAP data to be transmitted, whereas once for M + P (or MP) times (
The transmission frequency can be controlled by setting data that allows the wireless terminal 4 to transmit data. Also, the transmission timing specified by the MAP data can be set so as to be convenient for the relay station 3. Also, such a reflection rule is
It can be continued until P data is transmitted N times. Furthermore, when the type of data to be transmitted to the wireless terminal 4 and the internal operation can be designated by the MAP data, the MAP data is set based on the control signal from the relay station 3. For example, the MAP data is adjusted to have the content requested by the control signal, and is generated as MAP data to be transmitted.

Then, when the MAP data reflecting the content of the control signal from the relay station 3 is transmitted from the wireless base station 2, the wireless terminal 4-1 receives it, and the control unit 62 transmits the reflected MAP data. The internal operation and transmission operation are controlled based on the above.

For example, reception quality (CINR) is measured for a designated signal, and CQI data corresponding to the reception quality measured at a designated timing is transmitted.

Since the relay station 3 receives the radio signal transmitted from the radio terminal 4 at the timing and channel specified by the MAP data from the radio base station 2, the relay station 3 receives the target transmission signal that is requested to be changed by the control signal. Can do.

  The processing flow in the control unit 41 of the relay station 3 is shown in FIG.

That is, the control unit 41 of the relay station 3 determines whether or not control of the transmission operation is necessary for the subordinate radio terminal 4 (for example, only 4-1), and if it is determined that it is necessary, the parameter desired to be changed. To decide. For example, MS Basic CID, Period, Frame Off
Parameters such as set, Duration, and Report Configuration. Then, a control signal including the parameter is transmitted to the radio base station 2, and MAP data (in particular, UL MAP data) in which the control signal is reflected is received. Then, the reception processing unit of the relay station 3 receives the radio signal transmitted from the radio terminal 4 according to the UL MAP data.

For example, the reception processing unit measures the reception quality of the received radio signal, and then changes the modulation scheme, encoding scheme, encoding rate, etc. when transmitting to the radio terminal 4 based on the reception quality.

Alternatively, only reception may be performed, and the received signal may be stored in a storage unit included in the control unit 41. This is because it can be used for later analysis and can be reported to the radio base station 2 via the MMR link as necessary.

[B] Description of Second Embodiment In the first embodiment, the transmission operation of the wireless terminal is controlled. In this embodiment, the reception operation of the wireless terminal is controlled.

That is, when the control unit 41 of the relay station 3 determines that it is necessary to control the reception operation of the subordinate radio terminal 4 (4-1), the control unit 41 generates the content desired to be reflected in the MAP data as a control signal. Then, the data is transmitted to the radio base station 2 via the MMR link via the transmission processing unit.

Then, the control unit 25 of the radio base station 2 receives this control signal, and reflects the content of the control signal in MAP data (particularly DL MAP) to be transmitted thereafter.

Accordingly, the MAP data reflecting the control signal from the relay station 3 is transmitted from the wireless base station 2, and the wireless terminal 4 (4-1) receiving the reflected MAP data receives the reflected M
A reception operation (reception process) is performed based on the AP data. The contents of the control signal can be the same as those in the first embodiment, and the object to be reflected may be DL MAP data.

Hereinafter, retransmission control (in particular, HARQ (Hybrid used in WCDMA systems)
(Auto Repeat request)) will be described with reference to FIG. 9 as an example of the case where the wireless terminal 4 has a function.

In addition, the structure similar to what was shown to FIGS. 2-4 can be used for the structure of the wireless base station 2, the relay station 3-1, and the wireless terminal 4-1.

  FIG. 9 is a diagram illustrating a sequence for performing retransmission control.

First, the reception processing unit of the wireless terminal 4-1 receives the preamble transmitted from the wireless base station 2, synchronizes with the wireless frame transmitted from the wireless base station 2, and receives MAP data based on the preamble. Do. The MAP data is analyzed by the MAP data information analysis unit 58 and the analysis result is given to the control unit 62. Therefore, the control unit 62 grasps the transmission / reception timing of data (for example, user data) designated by the MAP data, and controls the transmission processing unit and the reception processing unit to operate according to the designated timing. Here, user data designated by the MAP data is received.

On the other hand, the reception processing unit of the relay station 3 also receives the preamble transmitted from the radio base station 2 to synchronize with the radio frame transmitted from the radio base station 2, and receives MAP data based on the preamble. And receiving user data addressed to the wireless terminal 4-1 via the MMR link. Then, the received user data is transmitted to the wireless terminal 4-1 at the transmission timing designated by the wireless terminal 4-1 by the MAP data. However, at that time, the control unit 41 of the relay station 3 performs control so that a copy of the transmission data is stored in the storage unit (or the PDU buffer unit 37). Further, error detection processing is performed on the decoding result of the user data obtained by the reception processing unit. Note that data obtained as a result of decoding is error detection encoded. That is, error detection coding (for example, addition of CRC bits) is performed before (error correction) coding in the transmission processing unit of the radio base station 2 or the relay station 3 on the transmission side. Then, the error detection result and the received user data are stored in the storage unit of the control unit 41 together with identification data such as a radio frame number.

The wireless terminal 4-1 that has received the user data from the relay station 3-1 is demodulated and (error correction) decoded by the reception processing unit, and error detection processing is performed on the decoding result using CRC bits and the like.

Here, if there is no error, an ACK signal is transmitted via the relay station 3 at the timing specified by the MAP data, and if there is, an NACK signal is transmitted. Even when the NACK signal is transmitted, the wireless terminal 4-1 holds (stores) the received data in the storage unit included in the control unit 62.

The control unit 41 of the relay station 3 that has received the ACK signal can notify the radio base station 2 that the data has arrived correctly by transferring the data to the radio base station 2. .

On the other hand, when the NACK signal is received, the relay station 3 needs to retransmit the user data to the wireless terminal 4-1, but cannot perform transmission unless the MAP data is controlled.

Therefore, the control unit 41 of the relay station 3 generates a control signal and transmits it to the radio base station 2 via the MMR link. An example of the control signal is shown in FIG.

In this example, the control signal is Frame Number, Index, ACK / NACK.
(Between BS and RS), ACK / NACK (between RS and T).

Frame Number and Index are information for specifying which user data the information is about. The number of the radio frame when the data is transmitted and the user data transmitted in the same radio frame correspond to any of them. It is a number indicating whether to do. A
CK / NACK (between BS and RS) and ACK / NACK (between RS and T) indicate whether user data was received normally (no error detection) between BS and RS, or between RS and T, respectively. This is data for notifying by transmission of ACK or NACK whether transmission has been received normally (assuming no error is detected). The ACK / NACK (between BS and RS) has already been controlled by the control unit 41.
Can be set according to the error detection result stored in the storage unit. That is, this data area is set as ACK if there is no error and NACK if there is any error. ACK / N
The area of ACK (between RS and T) is set according to the content received from the wireless terminal 4-1. That is, ACK is set when the relay station 3 receives ACK, and NACK is set when NACK is received.

Therefore, the control unit 25 of the radio base station 2 sends this control signal to the relay station 3 via the MMR link.
ACK / NACK (between BS and RS), ACK / NACK (RS
, T) is reflected in the MAP data to be transmitted thereafter.

That is, if the BS and the RS are NACK, the control unit 25 of the radio base station 2 assigns to the MAP information generation unit 24 the timing for transmitting data to the radio terminal 4-1. Is generated and transmitted from the transmission processing unit.

In this case, the user data is retransmitted from the radio base station 2 according to the MAP data in the same manner as described above, the relay station 3 transfers the user data, and the radio terminal 4-1 transmits the retransmission data via the relay station 3. After receiving and combining with the previously received and stored data, error correction decoding and error detection are performed again.

When the BS and the RS indicate ACK and the RS and T indicate NACK, the control unit 25 of the radio base station 2 transmits data to the MAP information generation unit 24 to the radio terminal 4-1. MAP data to which the timing is assigned is generated and transmitted from the transmission processing unit.

However, in this case, retransmission of user data according to the MAP data from the radio base station 2 is not performed. Instead, the relay station 3 controls the transmission processing unit so as to transmit the user data stored in the storage unit of the control unit 41 to the wireless terminal 4 according to the MAP data. In this way, there is no need to retransmit from the radio base station 2 again.

The wireless terminal 4-1 receives the retransmission data transmitted from the relay station 3, combines it with the previously received and stored data, and again performs error correction decoding and error detection.

The control unit 25 of the radio base station 4-1 determines that the reception is normally completed in the radio terminal 4 when the BS and the RS and between the RS and T indicate ACK, and the following is performed as necessary. Performs processing for data transmission.

As described above, the relay station 3 can control the reception operation of the wireless terminal 4 by transmitting the control signal to the wireless base station 2.

11 and 12 show a processing flow in the relay station 3 and a processing flow in the radio base station 2, respectively.

  FIG. 11 shows a processing flow in the relay station 3.

The relay station 3 receives the MAP from the radio base station 2 and transmits the transmission timing (Fra) addressed to the radio terminal 4.
me Number n, Index i), acquires a channel, receives user data (HARQ data) to be transmitted at the timing via the MMR link, and transmits the user data at the transmission timing and channel at which the user data is acquired.

Then, the received user data (HARQ data) is demodulated and decoded. Note that when data is transmitted (transmitted) to the wireless terminal 4, decoding of the user data received from the wireless base station 2 is omitted, and the modulation unit 39 does not encode the demodulated data. It can also be modulated and transmitted. In this case, decoding is executed for the first time at this stage (after data transfer to the wireless terminal 4), but if it is in time for transmission, decoding (error correction decoding) is performed, and the error-corrected signal is again transmitted. It is desirable to transmit after encoding and modulation.

When the relay station 3 finishes decoding, the relay station 3 determines whether or not there is an error. If there is an error here, the control signal (A) is transmitted to the radio base station 2. The content of the control signal A is Frame
Number: n, Index: i, Between BS and RS: Between NACK, RS and T4-1: NA
CK.

If there is no error, the received user data (HARQ data) is held in the storage unit of the control unit 41, and the reception of the reception result from the wireless terminal 4-1 is awaited.

When the reception result is received, it is determined whether or not it is ACK. If it is ACK, the control signal B is transmitted to the radio base station 2. The contents of the control signal B are Frame Number: n, In
dex: i, between BS and RS: ACK, between RS and T4-1: ACK.

On the other hand, if the reception result is NACK, it is determined whether or not HARQ data is held, and N
If it is o, the process ends, and if it is determined that it is held, the control signal C is sent to the radio base station 2
Send. The contents of the control signal C are as follows: Frame Number: n, Index: i, B
Between S and RS: ACK, between RS and T4-1: NACK.

Then, MAP data transmitted from the radio base station 2 is received, and HARQ data held in the storage unit is read and retransmitted. The retransmission at that time is performed at the timing specified by the MAP data. Here, Frame Number: n + q, Ind
ex: j.

  FIG. 12 shows a processing flow in the radio base station 2.

After transmitting user data, the radio base station 2 receives a control signal from the RS. When the control signal indicates that the reception result between the BS and the RS is NACK, the radio base station 2 defines the data transmission timing for retransmission using the MAP data, and transmits the HARQ data related to the retransmission to the relay station. 3 to retransmit to the wireless terminal 4. On the other hand, the reception result between the control signal BS and the RS is
When indicating that it is ACK, the radio base station 2 checks the reception result between the RS and the MS, and if it is ACK, does not perform retransmission processing of the user, and starts transmission processing of the next data,
If it is NACK, the data transmission timing for retransmission is defined by MAP data. However, in this case, since retransmission uses data stored in the relay station 3, the radio base station 2 to the relay station 3
Do not retransmit to.

When the relay station 3 detects that there is an error in the user data received from the radio base station 2, the relay station 3 does not perform the process of transmitting user data to the radio terminal 4, and F
It is preferable that information corresponding to the frame number and index is stored, and a control signal storing NACK as a reception result between the BS and the RS is transmitted to the radio base station 2 via the MMR link. This is because even if data that is difficult to be corrected by the relay station 3 is transmitted to the wireless terminal 4, it is unlikely that the error correction will succeed in the non-terminal terminal 4.

However, when using HARQ, since the success rate of decoding increases by combining already received data with retransmission data, even if the reception result between the BS and the RS is NACK, the wireless terminal 4
It is also possible to transmit erroneous data. That is, the control unit 62 of the wireless terminal 4 stores the erroneous received data in the storage unit, combines it with the retransmitted data, and then performs decoding, so that the erroneous received data is also used meaningfully. be able to.

Note that not only the wireless terminal 4 but also the relay station 3 performs decoding by combining the already received data with the retransmission data (which can be considered as various combinations such as taking the average probability of each bit). The possibility can be increased.

In this embodiment, a NACK signal is transmitted.
The fact that the signal cannot be received within a predetermined time is interpreted as being synonymous with the transmission of the NACK signal, and the same control can be performed.

In addition, when both the BS and the RS, and between the RS and the MS are NACK, one aggregated NAC
It can also be transmitted from the relay station 3 to the radio base station 2 as K information.

Wireless communication system Wireless base station 2 Relay station 3 Wireless terminal 4 Wireless frame format Uplink communication control sequence Control signal (CQI transmission control signal) Uplink communication control sequence Retransmission control sequence Control signal (ACK / NACK message) Processing flow in relay station 3 Processing flow in the radio base station 2

DESCRIPTION OF SYMBOLS 1 Routing apparatus 2 Wireless base station 3 Relay station 4 Wireless terminal 10, 30, 50 Antenna 11, 31, 51 Duplexer 12, 32, 52 Receiving part 13, 33, 53 Demodulating part 14, 34, 54 Decoding part 15, 35 55 Control data extraction unit 16 Packet generation unit 17 NW interface unit 18 Packet identification unit 19 Packet buffer unit 20 PDU generation unit 21, 38, 59 Encoding unit 22, 39, 60 Modulation unit 23, 40, 61 Transmission unit 24 MAP Information generation unit 25, 41, 62 Control unit 36, 58 MAP information analysis unit 37, 57 PDU buffer unit 56 Data processing unit

Claims (6)

Receiving the first control signal from the radio base station a first control signal sent directly to the wireless terminal for controlling the receiving operation in the radio terminal, the relay station transmits radio signals to the wireless terminal in accordance with said first control signal In
A determination unit that determines whether it is necessary to control the reception operation in the wireless terminal based on a reception state from the wireless base station or the wireless terminal;
Based on the determination, the relay station generates a second control signal for controlling the reception operation of the wireless terminal transmits to the wireless base station, generated by the radio base station based on said second control signal a transmission processing unit for transmitting a radio signal to the thus wireless terminal to the first control signal,
A relay station comprising: Directly transmit the first control signal for controlling the reception operation of the wireless terminal to the wireless terminal, and transmits via a wireless signal relay station to the radio terminals under the control of receiving operation by said first control signal wirelessly In the base station
The relay station determines whether it is necessary to control the reception operation in the wireless terminal based on the reception state from the wireless base station or the wireless terminal , and the relay station performs the reception operation of the wireless terminal. A reception processing unit for receiving a second control signal based on the determination ,
A transmission processing unit that said generating said first control signal based on the second control signal, and transmits,
A radio base station comprising: Receiving the first control signal from the radio base station a first control signal sent directly to the wireless terminal that controls the reception operation of the wireless terminal, the first data included in the radio signal received from the radio base station the control signal is therefore in the relay station to transmit to the wireless terminal,
A determination unit that determines that it is necessary to control the reception operation in the wireless terminal when an error is detected in the received data ;
A transmission processing unit that generates a second control signal indicating that an error in the data has been detected based on the determination result of the determination unit and transmits the second control signal to the radio base station;
And a reception processing unit for receiving data according to the retransmission of the data from the radio base station,
The transmission processing section, to the wireless terminal operating in accordance with the first control signal generated by the radio base station based on the second control signal, the radio base station based on the second control signal the generated first control signal therefore, the relay station and transmitting a radio signal containing data relating to feed該再received in the wireless terminal. Receiving the first control signal from the radio base station a first control signal sent directly to the wireless terminal that controls the reception operation of the wireless terminal, the first data included in the radio signal received from the radio base station In the relay station that transmits to the wireless terminal according to the control signal ,
A storage unit for storing the data received from the radio base station ;
Error is not detected for the data received from the radio base station, when receiving a signal indicating that detected the Ri erroneous for the data from the wireless terminal which has received the data, the reception operation in the wireless terminal A determination unit that determines that control is necessary;
Based on the determination result of the determination unit, and a transmission processing unit in which an error of the data is transmitted to the radio base station to generate a second control signal indicating that detected in the wireless terminal,
The transmission processing section, to the wireless terminal operating in accordance with the first control signal generated by the radio base station based on the second control signal, retransmits the data by using the data stored in the storage unit generate, thus to the first control signal generated by the radio base station based on the second control signal, the relay station and transmitting a radio signal containing the retransmitted data to the wireless terminal . A radio base that directly transmits a first control signal for controlling a reception operation in a radio terminal to the radio terminal, and transmits data included in the radio signal to the radio terminal via a relay station according to the first control signal In the station
A transmission processing unit for transmitting a wireless signal including data to be transmitted to the wireless terminal according to the first control signal;
The second control signal error for the data received is transmitted is generated when it is detected in the relay station and a reception processing unit for receiving from said relay station,
The transmission processing section, to the wireless terminal operating in accordance with the first control signal generated based on the second control signal, via the relay station, including the data relating to the retransmission of the data radio the signal, that sends according to said first control signal generated based on the second control signal
Radio base station which is characterized a call. A radio base station that directly transmits a first control signal for controlling a reception operation in a radio terminal to the radio terminal, and transmits data included in the radio signal to the radio terminal via a relay station according to the first control signal In
A transmission processing unit for transmitting a wireless signal including data to be transmitted to the wireless terminal according to the first control signal;
A reception processing unit that receives from the relay station a second control signal that is generated and transmitted when no error is detected for the data received at the relay station and an error is detected for the data received at the wireless terminal It equipped with a door,
The transmission processing unit, the second control the signal generating and transmitting a first control signal based on, the data relating to the retransmission of the data, transmission to the relay station has a performed
Radio base station which is characterized a call.

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