WO2008148293A1

WO2008148293A1 - Method and device for realizing data packet automatic repeat request in wireless communication network

Info

Publication number: WO2008148293A1
Application number: PCT/CN2008/000937
Authority: WO
Inventors: Liyu Cai
Original assignee: Alcatel Lucent
Priority date: 2007-05-30
Filing date: 2008-05-13
Publication date: 2008-12-11
Also published as: CN101316373A

Abstract

A method and device to control/assist a data packet automatic repeat request, controls a source device to send a objective data packet to a objective device and a repeat request assist device from different transfers path, if the objective device didn't correctly receive the objective data packet, then controls the repeat request assist device to repeat request the objective data packet which received and stored by different from the transfers path of the objective device to the objective device.

Description

Used in wireless communication networks

Method and device for automatically retransmitting data packets

The present invention relates to a wireless communication network, and more particularly to a method and apparatus for automatically retransmitting data packets in a wireless communication network. Background technique

Automatic retransmission (ARQ) is an error control scheme in a communication network, that is, a mechanism that requires the sender to retransmit a packet after the receiver detects an error (failure to receive the packet correctly). On this basis, in order to ensure reliable transmission of data under wireless fading channel conditions, compensate for the received bit error rate caused by fast fading and shadow, a hybrid automatic combining forward error correction coding (FEC) and ARQ is generated. Retransmission (HARQ) technology.

1 is a topology diagram of a wireless non-relay communication network, which includes a base station BS1 and a plurality of mobile stations (only the mobile station MS1 and the mobile station MS2 are shown therein for the sake of brevity). Taking the downlink transmission between BS1 and MS1 as an example, in the initial transmission, the target data packet (hereinafter referred to as the data packet) is sent by the source device BS1 and then reaches the destination device MSI via the wireless channel, and the MS1 verifies the incoming data packet:

- If the check result is correct, MS1 will send a Receive Status Report message (containing ACK information and identification information of the packet) for reporting that it correctly received the packet to BS1, after which BS1 will schedule the next one. The initial transmission of the packet. For the sake of brevity, the above-mentioned reception status report message including ACK information is hereinafter referred to as an ACK message;

- If the result of the check is incorrect, MS1 will send a Receive Status Report message (containing NACK information and identification information of the packet) for reporting that it did not correctly receive the packet to BS1, based on which BS1 will arrange The data packet is retransmitted, for example, a corresponding time-frequency resource is determined, and the data packet is retransmitted by using the determined time-frequency resource. For the sake of brevity, the above-mentioned reception status report message containing NACK information is hereinafter referred to as a NACK message. It can be seen that in the existing non-relay network, the retransmission of the data packet is performed by the source device separately. Therefore, if the channel between the source device and the destination device is under the influence of fast fading or shadow for a long time, the data packet may not be correctly received by the destination device after multiple retransmissions, and the packet is discarded. .

With the introduction of the relay station, the topology of the wireless communication network has undergone a major change. The base station will not necessarily communicate directly with the mobile station, but will be based on factors such as channel quality (eg, between the base station and the mobile station via different paths). The signal strength of the communication) is selectively communicated via the one or more relay stations or directly with the mobile station. Figure 2 shows a topography of a wireless communication network in which a base station communicates with a mobile station via a primary relay station. The network shown includes a base station BS2, a relay station RSI and a plurality of mobile stations (for simplicity, only mobile stations MS3 and MS4 are shown). Taking the downlink transmission between BS2 and MS3 as an example, the data packet transmission in the prior art has the following solutions:

Solution 1. The relay station does not verify the target data packet.

BS2 first sends the target data packet to RS1;

RS1 directly forwards the target data packet to MS3;

MS3 verifies the received target packet forwarded by RS1:

If the check is correct, MS3 returns an ACK to BS2;

Otherwise, MS3 returns a NACK to BS2, which will retransmit the packet, and the retransmitted packet arrives at MS3 via RS1 relay.

Solution 2. The relay station verifies the target data packet, and the verification is correct before forwarding.

BS2 first sends the data packet to RS1;

RS1 verifies the received packet:

If the check is correct, RS1 sends the verified packet to MS3; MS3 verifies the target packet sent by RS1:

If the check is correct, MS3 will return an ACK message to BS2. Preferably, the ACK message is relayed by RS1;

Otherwise, MS3 returns a NACK message to BS2. Preferably, the NACK message is also relayed by RS1, and BS2 will allocate resources for RS1 to retransmit the data packet. Otherwise, the RSI returns a NACK message to BS2 requesting BS2 to retransmit the packet for it. Until the packet is correctly received, RS1 sends the packet to MS3. For Time Division Multiplexing (TDM) networks, it is assumed that the time required for a packet to arrive at another node by a node (base station or relay station or mobile station) in the network without relaying is T. Taking the above scheme 1 as an example, in the network shown in FIG. 2, the data packet initially transmitted by BS2 arrives at MS3 via RS1 takes 2 Τ; if MS3 does not correctly receive the data packet, BS2 will schedule based on the NACK message fed back by MS3. Retransmission, the retransmission of the packet will take up 2 传输 of transmission time. Here, it is assumed that after receiving the retransmission data packet, the MS3 corrects the result of the retransmission data packet verification (in the case of ARQ), or the data obtained by combining the retransmission data packet with the data packet of the initial transmission. If the result of the check ( HARQ ) is correct, the total time spent transmitting the data packet is 4Τ. If the result of the check performed after receiving the retransmitted data packet is incorrect, it may need to be retransmitted again. Therefore, the transmission of this packet will take more time.

Taking the above scheme 2 as an example, in the network shown in FIG. 2, the initial transmission of the data packet from the BS2 to the RS1 takes time; if the RS1 correctly receives the data packet, the RS1 sends the correctly received data packet to the MS3. Time. Thus, in the case where both RS1 and MS3 correctly receive the data packet, the total time required for transmission of the data packet is 2T. If the RSI or MS3 does not receive the packet correctly, the retransmission triggered by this will further extend the transmission time, that is, when the retransmission is triggered, the transmission time is at least 3T.

It can be seen that the above transmission scheme brings a long time for data packet transmission in the TDM network, thereby reducing the overall transmission efficiency of the network, and is not conducive to the full utilization of the wireless resources. In the more complex multi-level relay network (each stage includes one or more relay stations), the above problems also exist, and are more obvious because the number of relay stations is more. In addition, similar to the non-relay network, in the relay network shown in Figure 2, the retransmission of the target data packet is performed separately by the source device. Summary of the invention

In view of the above problems in the prior art, the present invention introduces a retransmission auxiliary device in a wireless non-relay network/relay network, respectively, in which the data packet is not correct by the destination device. Upon reception, the secondary source device performs retransmission of the data packet, and correspondingly, a corresponding method and apparatus (module) for controlling the retransmission assistance device is also introduced for the base station.

According to a first aspect of the present invention, a method for controlling automatic retransmission of a data packet in a base station of a wireless communication network is provided, wherein the method includes the following steps: determining whether the destination device correctly receives the target data packet; If the destination device does not correctly receive the target data packet, control one or more retransmission auxiliary devices corresponding to the destination device to retransmit the target data packet received and saved by using a different transmission path from the destination device. Give the device of the purpose.

According to a second aspect of the present invention, there is provided a retransmission control apparatus for controlling automatic retransmission of a data packet in a base station of a wireless communication network, wherein the first determining means is configured to determine whether the destination device is correct Receiving a target data packet; the first control device, configured to: when the destination device does not correctly receive the target data packet, control one or more retransmission auxiliary devices corresponding to the destination device to communicate with the destination device The target data packet received and saved by the different transmission paths is retransmitted to the destination device.

According to a third aspect of the present invention, a method for assisting automatic retransmission of a data packet in a retransmission auxiliary device of a wireless communication network is provided, comprising the steps of: The target data packet received and saved by the different transmission paths of the destination device is retransmitted to the destination device that does not correctly receive the target data packet.

According to a fourth aspect of the present invention, there is provided a retransmission assistance apparatus for assisting automatic retransmission of a data packet in a retransmission assistance device of a wireless communication network, characterized in that it is passed through its corresponding purpose The target data packet received and saved by the different transmission paths of the device is retransmitted to the destination device that does not correctly receive the target data packet.

The technical solution provided by the present invention introduces diversity gain and additional reliability in data packet retransmission for a non-relay network; in the relay network, not only diversity gain can be introduced, but also participation data can be flexibly selected. Retransmission of packets and devices that are initially transmitted to optimally utilize system resources. DRAWINGS Other features, objects, and advantages of the present invention will become apparent from the Detailed Description of Description

Figure 1 shows a topology diagram of a wireless non-relay communication network;

Figure 2 shows a topology diagram of a wireless relay communication network;

3 is a flow chart of a method for controlling automatic packet retransmission in a base station of a wireless communication network in accordance with an embodiment of the present invention;

4 is a network topology diagram of the retransmission auxiliary device provided by the present invention in the non-relay network shown in FIG. 1 according to an embodiment of the present invention;

FIG. 5 is a diagram showing a network topology after the retransmission auxiliary device provided by the present invention is introduced in the relay network shown in FIG. 2 according to an embodiment of the present invention;

6 is a block diagram of a retransmission control apparatus for controlling automatic packet retransmission in a base station of a wireless communication network according to an embodiment of the present invention;

7 is a flow chart of a method for assisting automatic packet retransmission in a retransmission auxiliary device of a wireless communication network according to an embodiment of the present invention;

Figure 8 is a block diagram of a retransmission assistance device for assisting automatic packet retransmission in a retransmission assistance device of a wireless communication network in accordance with an embodiment of the present invention.

Wherein, the same or similar reference numerals denote the same or similar device (module) or step features. detailed description

3 is a flow diagram of a method for controlling automatic packet retransmission in a base station of a wireless communication network in accordance with an embodiment of the present invention. The method is described in detail below for various network topologies.

Non-relay network

An example of the application of the present invention to a non-relay network is shown in Fig. 4, in which the retransmission assistance device provided by the present invention is introduced. According to the present invention, the retransmission assistance device can be implemented by modifying an existing relay station (e.g., configuring a retransmission assistance device thereon), or by introducing a network device dedicated to assisting retransmission. In the network shown in FIG. 4, the retransmission auxiliary device XI (hereinafter referred to as XI) corresponds to MS1, that is, XI retransmits the data packet when MS1 does not correctly receive the data packet from BS1. Taking the downlink transmission between BS1 and MS1 as an example, in the initial transmission shown in step S10, BS1 controls to transmit the data packet to MS1 and XI via different transmission paths. The control in step S10 can be understood as BS1 allocates radio resources for MS1, XI and itself for the initial transmission of the data packet. The packet transmitted for the first time is transmitted from BS1 to MS1 via transmission path L1, and arrives at XI via transmission path L2 different from L1. Preferably, the same radio resource for receiving downlink data from BS1 may be allocated to MS1 and XI by the BS1 for the initial transmission, and then the BS1 transmits the data packet downward by using the same downlink radio resource.

Thereafter, the destination device MS1 will verify the data packet (e.g., cyclic redundancy check, CRC). It should be understood that the specific check mode does not constitute a limitation on the protection scope of the present invention. In addition, it should be understood that, for a communication scheme using HARQ, when the target data packet is initially transmitted, the verification of the target data packet refers to performing verification on the target data packet; and when the target data packet is retransmitted, The verification of the target data packet refers to performing a check on the combined result after combining the target data packet received in the retransmission with the previously received target data packet.

If the verification result of the data packet by the MS1 is correct, it indicates that the MS1 correctly receives the data packet, and then the MS1 sends an ACK message to the BS1. In step S11, the BS1 extracts the ACK information and other corresponding information after receiving the ACK message. The information (e.g., the packet identification information) can be judged by the judgment that the data packet has been correctly received by the MS1, and then the initial transmission of the next downlink data packet is scheduled.

Preferably, the XI also receives the ACK message, and extracts the ACK information and the packet identification information therefrom, so as to determine that the data packet has been correctly received by the MS1, and then the XI discards the received and saved in the initial transmission. A copy of the packet, and waiting to receive the next packet transmitted for the first time. Similarly, for network operators and equipment manufacturers, they may not want equipments such as XI to have higher complexity. Therefore, XI may not have the above-mentioned judgment function, but simply follow BS1 based on the judgment result. Do the scheduling and do it. Subject to a variety of factors, the channel quality between BS1 and MSI may be poor, resulting in bit errors. Therefore, the packet originally transmitted by BS1 to MS1 is not correctly received by MS1. At this time, MS1 will send NACK to BS1. Message.

After determining in step S11 that the MS1 has not correctly received the data packet based on the NACK message from MS1 (extracting the NACK information therein and the data packet identification and analysis), in step S12, BS1 will control XI to receive it previously via L2. And save a copy of the packet to retransmit to MS1. Preferably, in step S12, in order to introduce a gain, BS1 and XI jointly perform retransmission of the data packet, and the joint retransmission includes the following implementation manner:

- BS1 and XI use the same radio resources (such as time-frequency resources) to retransmit the same data to MS1 (for example, retransmit the complete data packet to MS1 respectively), then on MS1, only need to receive the heavy Transmit packets to perform radio frequency (RF) merging or maximum ratio combining;

- BS1 and XI use the same radio resources to retransmit different data to MS1 (eg, retransmit the first part and the second part of the data packet to MS1 respectively), which can be regarded as a cooperative spatial multiplexing, then in MS1 End, it is necessary to perform spatial multiplexing detection on the received retransmitted data packet;

- After performing STBC (space time block coding) or SFBC (space frequency block coding) on the retransmitted data packet, BS1 and XI use the same radio resource to send the retransmitted data packet after the above encoding to MS1. Considering a cooperative STBC or cooperative SFBC, on the MS1 side, the corresponding retransmission data packet needs to be decoded by STBC/SFBC.

Since there is a spatial distance between BS1 and XI, the above method can introduce diversity gain including at least spatial diversity gain for retransmission.

In this example, the description is mainly directed to a transmission scheme using the HARQ technology, that is, after the destination device demodulates the initially transmitted data packet to obtain the demodulated initial transmission data, if the verification result is incorrect, the foregoing is retained. Demodulated initial transmission of data. After receiving the retransmission data packet from BS1 and XI, MS 1 demodulates the retransmitted data packet to obtain demodulated retransmission data, and then demodulates the retransmitted data and the stored solution. The initial transmission data of the tone is weighted and combined for verification. Those skilled in the art It can be understood that in the scenario supporting multiple retransmissions, MS1 preferably retains the demodulated retransmission data obtained by demodulating the previous (one or more) retransmission data packets and the demodulated initial transmission. Data, used to perform verification after combining with the demodulated current retransmission data.

If MS1 checks the result of the weighted combined data correctly, it will return an ACK message to BS1, and BS1 will judge based on the message that MS1 correctly receives the target data packet after retransmission, and then schedules the next target. The initial transmission of the data packet; if MS1 incorrectly checks the weighted combined data, it will return a NACK message to BS1, request a second retransmission, or discard the data packet. How to choose is usually determined by the specific settings of the network. For example, a retransmission threshold is set, and the transmission of the packet is abandoned when the number of retransmissions reaches the threshold.

Optionally, as a special subscriber station of BS1, XI may verify the initial transmission data packet sent by BS1 received by L2, or may not perform the above verification. The case where XI does not perform verification has been disclosed by the above.

As for the case where the XI verifies the initial transmission packet sent by the BS1 via the L2, when the verification result is correct, the XI can rely on the saved copy of the data packet in step S12. The secondary BS1 performs the retransmission of the data packet, and the specific process is the same as when the XI does not perform the verification; when the verification result of the data packet sent by the XI to the BS1 is an error, optionally:

- XI ignores the error of the packet, and the secondary BS1 performs retransmission of the packet as if the packet check is not performed or the check result is correct;

- XI sends a NACK message to BS1, requesting BS1 to retransmit the data packet to it, if MS1 does not correctly receive the data packet, XI will not assist BS1 to perform retransmission of the data packet, and BS1 performs the same pass.

In order to make the retransmission auxiliary equipment meet the requirements of simple design and low cost, all the scheduling and control functions can be concentrated at the base station. Therefore, XI can fully rely on the scheduling of BS1 without judging whether or not it participates in retransmission. This will be discussed in detail below in the description of the third and fourth aspects of the invention.

It should be understood that in Figure 4 and subsequent network topologies, only for the sake of simplicity A retransmission auxiliary device of the destination device. In practical applications, multiple retransmission auxiliary devices can be configured for a more important destination device (such as a base station or a relay station), thereby introducing more diversity gain and enhancing reliability.

In the network shown in FIG. 4, for the uplink transmission, please refer to the description above in connection with the downlink transmission, and it should be understood that when the BS1 is used as the destination device, it will not need to rely on receiving the external ACK/NACK message to judge whether the destination device correctly receives the target data. The packet itself can make the above judgment (that is, for the data packet sent by MS1, BS1 can check whether it has correctly received the data packet by checking it).

Relay network

FIG. 5 is a diagram showing a new network topology after the introduction of the retransmission auxiliary device provided by the present invention in the relay network shown in FIG. 2 according to an embodiment of the present invention, wherein the retransmission assistance is assumed The device X2 (hereinafter referred to as X2) corresponds to BS2, that is, when BS2 does not correctly receive the uplink data packet, X2 retransmits the target data packet for it. Those skilled in the art understand that BS2 may have a plurality of retransmission auxiliary devices corresponding thereto, and only X2 is shown for the sake of simplicity in the figure.

The following takes the uplink data transmission between MS3 and BS2 as an example. According to a preferred embodiment of the present invention, X2 can be obtained by modifying RS1 shown in Fig. 2.

A preferred embodiment of the present invention will now be described with reference to FIG.

It is assumed that MS3 moves to a location where the channel quality between MS3 and BS2 is acceptable, i.e., the channel quality allows direct communication between BS2 and MS3 without relaying. BS2 can determine the channel quality by the signal strength of the ranging request it receives.

When the above positional relationship is satisfied between MS3 and BS2, in step S10, preferably, BS2 controls MS3 to directly transmit the data packet to X2 and BS2 via paths L3, L4, respectively.

Thereafter, BS2 will demodulate the received data packet from the initial transmission from MS3 to obtain demodulated initial transmission data, after which the demodulated initial transmission data will be verified and the inspection result obtained. , to obtain the judgment result in step S11. When the judgment result in the step S11 is that the data packet of the initial transmission is not positive by the BS2 When receiving (verification result error), in step S12, BS2 will control MS3 to retransmit the data packet directly to BS2 via path L4, and control X2 via its transmission path L5 with BS2 (different from MS3 and The transmission path between BS2) retransmits the data packet previously received and saved to BS2. Among them, X2 performs the retransmission with MS3 regardless of whether the packet is correctly received by itself.

Of course, BS2 may also select whether X2 is required to participate in performing retransmission of the data packet according to a reception status report message or the like from X2, for example, if X2 does not correctly receive the data packet (X2 sends a NACK message to BS2) Then, only MS3 is controlled to retransmit the data packet to BS2. When BS2 has a plurality of retransmission assistance devices corresponding thereto, preferably, BS2 selects those retransmission assistance devices that have correctly received the data packet to retransmit the data packet with MS3.

Preferably, in the present invention, the determining manner of the retransmission auxiliary device corresponding to the destination device includes: determining a signal strength between the retransmission auxiliary device and the corresponding destination device according to the ranging signal sent by each retransmission auxiliary device. Etc.) to determine. That is, a retransmission auxiliary device having a strong signal strength with the destination device is selected as the retransmission auxiliary device corresponding thereto. In addition, each retransmission auxiliary device that finally participates in the retransmission of the data packet may be further determined according to the reception status (whether or not received correctly) of the initially transmitted data packet according to each retransmission auxiliary device corresponding to the destination device.

Another embodiment of the method will be described below with reference to FIG. 3 and with reference to FIG. 5 in which uplink data transmission between MS4 and BS2 is taken as an example. It is assumed that MS4 is far away from BS2 and communicates via RS2, and it is assumed that RS2 does not verify the data packet but simply forwards it, and the retransmission auxiliary device corresponding to BS2 is X2.

Thus, in step S10, BS2 controls MS4 to transmit the initially transmitted data packet to BS2 via L7-L6, and sends the data packet to X2 via L8.

If BS2 fails to correctly receive the packet, after obtaining the negative judgment result in step S11, BS2 may control X2 to retransmit the previously received and saved data packet to BS2 in step S12. Thus, the time required for the retransmission is only T, which is reduced by half compared to the prior art (as described in the background art, requiring 2T), which is undoubtedly beneficial to improve the overall data transmission rate of the communication system. According to a variant of the embodiment, when retransmitting the data packet, the BS2 controls the MS4 to transmit the retransmission data packet to the BS2 without RS2 relay (the corresponding transmission path is not shown in the figure), and controls the X2 heavy Pass the packet to get the diversity gain.

According to another embodiment of the present invention, in the initial transmission of the data packet, the BS2 controls the MS4 to transmit the initial transmission data packet to the BS2 without RS2 relay (the corresponding transmission path is not shown in the figure), and controls the MS4. Send the packet to X2. At the time of retransmission, the control MS4 transmits the retransmission packet to the BS2 without the RS2 relay, and controls X2 to perform the retransmission with the MS4. Then, in the present embodiment, the initial transmission and the retransmission time T are respectively 2 Τ, which is superior to the prior art (the initial transmission and the total retransmission are at least 3 Τ). The optimal situation of this embodiment is as described in the preferred embodiment described above (the distance between the destination device and the source device is relatively close).

6 is a block diagram of a retransmission control apparatus for controlling automatic packet retransmission in a base station of a wireless communication network in accordance with an embodiment of the present invention. The retransmission control device will be described below with reference to the network environments shown in Figs. The retransmission assistance device 10 includes: a first control device 100, a first determination device 101, and a second control device 102. Further, the first determination device 101 includes: a receiving device 1010, an extraction device 1011, and a Second judging device 1012.

Non-relay grid

An example of the application of the present invention to a non-relay network is shown in Fig. 4, in which the retransmission assistance device provided by the present invention is introduced. In accordance with the present invention, the retransmission assistance device can be implemented by modifying an existing relay station (e.g., by configuring a retransmission assistance device thereon), or by introducing a network device dedicated to assisting retransmission.

In the network shown in FIG. 4, the retransmission auxiliary device XI (hereinafter referred to as XI) corresponds to the MS1, that is, when the XI does not correctly receive the data packet from the BS1 (the retransmission control device provided by the present invention is configured). Retransmit the packet for it. Taking the downlink transmission between BS1 and MS1 as an example, the second control device 102 controls to transmit the data packet to MS1 and XI via different transmission paths. Wherein, the control can be understood as BS1 allocates radio resources for MS1, XI and itself for the initial transmission of the data packet. The packet transmitted for the first time is sent by BS1 to MS1 via transmission path L1, and via L1. The different transmission path L2 reaches XI. Preferably, the second control device 102 can allocate the same radio resource for receiving downlink data from the BS1 to the MS1 and the XI for the initial transmission, and then use the same downlink radio resource by a transmitting device not shown in the figure. The packet is sent down so that the XI can receive the target packet.

Thereafter, the destination device MS1 will check the data packet (for example, cyclic redundancy check, CRC). It should be understood that the specific check mode does not constitute a limitation on the scope of the present invention. In addition, it should be understood that for HARQ When the target data packet is initially transmitted, the verification of the target data packet refers to performing verification on the target data packet, and when the target data packet is retransmitted, the verification of the target data packet is After the target data packet received in this retransmission is merged with the previously received target data packet, the merge result is verified.

If the verification result of the data packet by the MS1 is correct, it indicates that the MS1 correctly receives the data packet, and then the MS1 sends an ACK message to the BS1, and the receiving device 1010 provides the ACK message to the extracting device 101 1 after receiving the ACK message. The latter extracts ACK information and other corresponding information (e.g., packet identification information) therefrom, and then the second judging device 1012 determines that the data packet has been correctly received by the MS1, and then the second control device 102 can schedule the next downlink. The initial transmission of the packet.

Preferably, the XI also receives the ACK message (which can be implemented by the BS1 to allocate a corresponding radio resource), and extracts ACK information and other related information (eg, packet identification information) therefrom, thereby determining that the ACK message is obtained. The data packet has been correctly received by MS1, and preferably, XI discards a copy of the data packet it received and saved in the initial transmission, waiting to receive the next initial transmitted data packet. Similarly, in order to reduce the complexity of XI and reduce the cost, XI may not have the above-mentioned judgment function, but simply follow the scheduling behavior of BS1 based on the judgment result.

Subject to a variety of factors, the channel quality between BS1 and MS1 may be poor, resulting in bit errors. Therefore, the packet originally transmitted by BS1 to MS1 is not correctly received by MS1. At this time, MS1 will send a NACK message to BS1. .

The receiving device 1010 receives the NACK message from the MS1 and supplies it to the extracting device 1011, from which the NACK information and other related information are extracted (eg, According to the packet identification information, the second judging device 1012 will thereby judge that the MS1 does not correctly receive the data packet, and provide the result of the determination to the first control device 100, and the first control device 100 will control the XI to receive it previously via L2. The saved copy of the packet is then retransmitted to MS1, which is then verified by MS1. Preferably, in order to introduce a gain, BS1 and XI jointly perform retransmission of the data packet, and the joint retransmission includes the following implementation manners:

- After performing STBC (space time block coding) or SFBC (space frequency block coding) on the retransmitted data packet, BS1 and XI use the same radio resource to send the retransmission data packet after the above encoding processing to MS1. Considering a cooperative STBC or cooperative SFBC, on the MS1 side, the corresponding retransmission data packet needs to be decoded by STBC/SFBC.

After receiving the retransmission data packet from BS1 and XI, MS1 demodulates the data packet and verifies the demodulated data. If the verification result is correct, it returns an ACK message, and BS1 will judge based on the message. The MS1 correctly receives the target data packet, and then schedules the initial transmission of the next target data packet; if the verification result is incorrect, MS1 will return a NACK, request a second retransmission, or discard the data packet, and how to choose is usually determined. The specific setting of the network (for example, setting a retransmission threshold, and discarding the transmission of the packet when the number of retransmissions reaches the threshold).

Optionally, as a special user station of BS1, XI may check the initial transmission data packet sent by BS1 received by L2, or may not perform the above verification. The case where XI does not perform verification has been disclosed by the above. As for the case where XI checks the initial transmission packet sent by BS1 received by L2, when the verification result is correct, XI can rely on the saved copy of the data packet by the first control device. 100 performs retransmission of the data packet; when the verification result is an error, optionally:

In order to make the retransmission auxiliary equipment meet the requirements of simple design and low cost, all the scheduling and control functions can be concentrated at the base station. Therefore, XI can fully rely on the scheduling of BS1 without judging whether or not it participates in retransmission. This will be discussed in detail below in the description of the third fourth aspect of the invention.

It should be understood that in FIG. 4 and subsequent network topology diagrams, only one retransmission auxiliary device of the destination device is shown for the sake of simplicity, and in practical applications, it may be a more important destination device (eg, a base station or a relay station). Configure multiple retransmission aids to introduce more diversity gain and increase reliability.

In the network shown in FIG. 4, for the uplink transmission, please refer to the description above in connection with the downlink transmission, and it should be understood that BS1 as the destination device will not need to rely on receiving the external ACK/NACK message to judge whether the destination device correctly receives the target data packet. The first judging device 101 can make the above judgment by itself (that is, for the data packet sent by the MS1, the BS1 can check whether it has correctly received the data packet by checking it).

Relay network

FIG. 5 is a schematic diagram showing a network topology after the retransmission auxiliary device provided by the present invention is introduced in the relay network shown in FIG. 2 according to an embodiment of the present invention, wherein the retransmission auxiliary device X2 is assumed. (hereinafter referred to as X2) Corresponding to BS2 (provided with the retransmission control device provided by the present invention), that is, when BS2 does not correctly receive the uplink data packet, X2 retransmits the target data packet for it. Those skilled in the art understand that BS2 may have a plurality of retransmission auxiliary devices corresponding thereto, and only X2 is shown for the sake of simplicity. Hereinafter, the uplink data transmission between MS3 and BS2 is taken as an example. According to a preferred embodiment of the present invention, X2 can be obtained by modifying RS1 shown in Fig. 2.

When the above positional relationship is satisfied between MS3 and BS2, preferably, the second control means 102 controls MS3 to directly transmit the data packets to X2 and BS2 via paths L3, L4, respectively.

Thereafter, BS2 will demodulate the received data packet from the initial transmission from MS3 to obtain demodulated initial transmission data, after which the demodulated initial transmission data will be verified and the inspection result obtained. The first judging device 101 thereby obtains a judgment result as to whether the BS 2 correctly receives the data packet. When the first judgment device 101 obtains the result that the initially transmitted data packet is not correctly received by the BS 2 (the check result is incorrect), preferably, the first control device 100 controls the MS3 to directly transmit the data packet via the path L4. Retransmitted to BS2, and control X2 to retransmit the data packet previously received and saved to BS2 via its transmission path L5 with BS2 (different from the transmission path between MS3 and BS2). Among them, whether or not X2 correctly receives the data packet, it performs retransmission of the data packet with MS3.

Of course, BS2 may also select whether X2 is required to participate in performing retransmission of the data packet according to a reception status report message or the like from X2, for example, if X2 does not correctly receive the data packet (X2 sends a NACK message to BS2) Then, only MS3 is controlled to jointly retransmit the data packet to BS2. When the BS 2 has a plurality of retransmission assistance devices corresponding thereto, preferably, the first control device 100 selects those retransmission assistance devices that have correctly received the data packet to retransmit the data packet with the MS 3.

Another embodiment of the retransmission control apparatus 10 will be described below with reference to FIG. 6 and with reference to FIG. 5 as an example in which uplink data transmission between MS4 and BS2 is taken as an example. Wherein, it is assumed that MS4 is far away from BS2 and communicates via RS2, and it is assumed that RS2 does not calibrate the data packet. The test is simple forwarding, and the retransmission auxiliary device corresponding to BS2 is X2. Then, the second control device 102 controls the MS 4 to transmit the initially transmitted data packet to the BS 2 via L7-L6, and transmits the data packet to X2 via L8.

If BS2 fails to correctly receive the packet, after the negative determination result is obtained in the first judging means 101, the first control means 100 retransmits the previously received and saved packet to the BS2 by the control X2. In this way, the retransmission time is only T, which is shortened by half compared with the prior art (as described in the background art), which is undoubtedly beneficial to improve the overall data transmission rate of the communication system.

According to a variant of the embodiment, when retransmitting the data packet, the first control device 100 controls the MS4 to transmit the retransmission data packet to the BS2 without RS2 relay (the corresponding transmission path is not shown in the figure), And control X2 to retransmit the packet to obtain the diversity gain.

According to another embodiment of the present invention, in the initial transmission of the data packet, the second control device 102 controls the MS4 to transmit the initial transmission data packet to the BS2 without RS2 relay (the corresponding transmission path is not shown in the figure) And control MS4 to send the packet to X2. At the time of retransmission, the first control device 100 controls the MS 4 to transmit the retransmission packet to the BS 2 without RS2 relay, and controls X2 to perform the retransmission with the MS 4 . Then, in this embodiment, the initial transmission and the retransmission time T are totaled 2T, which is superior to the prior art (the initial transmission and the retransmission total time are at least 3Τ). The optimal situation of this embodiment is as described in the preferred embodiment described above (the distance between the destination device and the source device is relatively close).

7 is a flow chart of a method for assisting in automatic retransmission of data packets in a retransmission assistance device of a wireless communication network, in accordance with an embodiment of the present invention. The method will be described below with reference to Fig. 7 and with reference to Fig. 4.

Taking the downlink transmission between BS1 and MS1 as an example, in step S20, XI receives the data packet sent by BS1 via L2 by using the radio resource allocated by BS1, and stores it. At the same time, BS1 also sends the same data packet to MS1 via path L1. Then, in step S21, XI determines whether the MS1 correctly receives the data packet sent by the BS1, and the determining process may be specifically implemented by receiving an ACK/NACK message from the MS1. If the judgment result is that the MSI does not correctly receive the data packet, the XI will transmit it according to the retransmission indication information (for example, resource allocation information) from BS1 via a different transmission path from MS1 (the destination device corresponding to XI) (MS1) The data received and saved via L2) via LI, XI is retransmitted to MS 1.

In order to minimize the complexity of the retransmission auxiliary device, the method can omit the judgment process described in step S21. After receiving and storing the copy of the data packet, the XI completely relies on the scheduling (instruction information) of the BS1 to perform the operation.

According to a specific embodiment of the present invention, as a special user equipment of the BS1, the XI can also verify the data packet from the BS1 and inform the BS1 of the verification result. When the XI fails to receive the packet correctly, it will send a NACK message to BS1. After learning that the XI has not received the packet correctly, BS1 will retransmit the packet by itself. When the MS 1 has a plurality of retransmission auxiliary devices corresponding thereto, preferably, the BS 1 selects, from among them, the retransmission assistance devices that correctly receive the initial transmission data packets sent by the BS 1 to participate in the retransmission of the data packets.

For the situation shown in Figure 5, reference is made to the description of the first and second aspects of the present invention and the description of the method in conjunction with Figure 4, and will not be described in detail herein.

Figure 8 is a block diagram of a retransmission assistance device for assisting automatic packet retransmission in a retransmission assistance device of a wireless communication network, in accordance with an embodiment of the present invention. The method will be described below with reference to Fig. 8 and with reference to Fig. 4, and the retransmission assisting device XI of Fig. 4 includes the retransmission assisting device 20 shown in Fig. 8.

The retransmission assisting device 20 shown in Fig. 8 includes: a third judging device 200 and a controlled retransmission device 201.

Taking the following line transmission as an example, one of the retransmission assistance devices 20 (not shown) receives the data packet sent by the BS1 via L2 using the radio resource allocated by the BS1, and hands it over to an auxiliary storage device (not shown). Out) save. Thereafter, the third determining apparatus 200 determines, according to the ACK/NACK message from the MS1, whether the MS1 correctly receives the data packet sent by the BS1, wherein the radio resource used for receiving the ACK/NACK message from the MS1 should also be allocated by the BS1. Give XI.

If the judgment result is that the data packet is not correctly received by the MS1, the controlled retransmission device 201 According to the retransmission indication information (for example, resource allocation information) from BS1, it is received and saved via a transmission path different from MS1 (the destination device corresponding to XI) (MS1 via L1, XI via L2) The packet is retransmitted to MS1.

In order to minimize the complexity of the retransmission auxiliary device, the third judging device 200 may be omitted. After receiving and storing the data packet replica, the controlled retransmission device 201 completely relies on the subsequent scheduling of the BS1 to perform subsequent operations.

For the case shown in Fig. 5, reference is made to the description of the first, second, and third aspects of the present invention and the description of the retransmission auxiliary device in conjunction with Fig. 4, and will not be described in detail herein.

The embodiments of the present invention have been described above, but the present invention is not limited to the specific systems, equipment, and specific protocols, and various modifications and changes can be made by those skilled in the art within the scope of the appended claims.

Claims

Claim

A method for controlling automatic packet retransmission in a base station of a wireless communication network, comprising the steps of:

b. Determine whether the destination device correctly receives the target data packet;

c. If the destination device does not correctly receive the target data packet, control one or more retransmission auxiliary devices corresponding to the destination device to receive and save the target data via a different transmission path from the destination device. The packet is retransmitted to the destination device.

2. The method according to claim 1, wherein before the step b, the method further comprises:

a. The control source device transmits the target data packet to the destination device and the one or more retransmission assistance devices via different transmission paths.

3. The method according to claim 2, wherein the step c further comprises the following steps:

Cl. If the destination device does not correctly receive the target data packet, controlling the source device and the one or more retransmission assistance devices to retransmit the target data packet to the destination device via a different transmission path.

The method according to claim 3, wherein the step cl further comprises:

C2. if the destination device does not correctly receive the target data packet, controlling the source device to join the target data packet with the one or more retransmission auxiliary devices via different transmission paths through one or more retransmission auxiliary stations. Retransmitted to the destination device.

The method according to claim 4, wherein the step c2 further comprises:

- if the destination device does not correctly receive the target data packet, controlling one or more relay devices between the source device and the transmission path of the destination device to communicate with the one or more retransmission assistance devices via different transmissions The path association retransmits the target data packet to the destination device.

The method according to any one of claims 2 to 5, wherein Step a also includes:

Controlling the source device to send the target data packet to the destination device through a first transmission path, and controlling the source device to send the target data packet to the one via another transmission path different from the first transmission path Or a plurality of retransmission auxiliary devices, wherein the first transmission path includes one or more relay stations.

The method according to any one of claims 1 to 6, wherein the source device comprises a base station itself, and the target device comprises a mobile station or a relay station; or

The source device includes a mobile station, and the target device includes a relay station or a base station itself; or

The source device includes a relay station, and the target device includes a base station itself, a relay station, or a mobile station.

The method according to claim 7, wherein, when the destination device is a relay station or a mobile station, the step b further includes:

Receiving a reception status report message from the destination device, which includes receiving status indication information indicating whether the device of the destination correctly receives the target data packet;

- extracting the reception status indication information from the reception status ^^ report message; - determining whether the destination device correctly receives the target data packet based on the extracted reception status indication information.

A retransmission control apparatus for controlling automatic packet retransmission in a base station of a wireless communication network, comprising:

a first determining means, configured to determine whether the destination device correctly receives the target data packet; the first control means, configured to: when the destination device does not correctly receive the target data packet, control one or more corresponding to the destination device The retransmission assistance device retransmits the target data packet received and saved via a different transmission path from the destination device to the destination device.

The retransmission control apparatus according to claim 9, further comprising: second control means, configured to control the source device to send the target data packet to the destination device and the one or more via different transmission paths Multiple retransmission auxiliary devices.

The retransmission control device according to claim 10, wherein The first control device is also used to:

And when the destination device does not correctly receive the target data packet, controlling the source device and the one or more retransmission auxiliary devices to jointly retransmit the target data packet to the destination device via different transmission paths.

12. The retransmission control device according to claim 1, wherein the first control device is further configured to:

When the destination device does not correctly receive the target data packet, controlling the source device to retransmit the target data packet by using the one or more retransmission auxiliary devices in association with the one or more retransmission auxiliary devices via different transmission paths. Give the device of the purpose.

The retransmission control device according to claim 12, wherein the first control device is further configured to:

When the destination device does not correctly receive the target data packet, control one or more relay devices between the source device and the transmission path of the destination device and the one or more retransmission auxiliary devices via different transmission paths The target packet is retransmitted to the destination device.

The retransmission control device according to any one of claims 10 to 13, wherein the second control device is further configured to:

Controlling the source device to send the target data packet to the destination device through a first transmission path, and controlling the source device to send the target data packet to the one or more via another transmission path different from the first transmission path a plurality of retransmission auxiliary devices, wherein the first transmission path includes one or more relay stations.

The retransmission control apparatus according to any one of claims 9 to 14, wherein the source device comprises a base station itself, and the target device comprises a mobile station or a relay station; or

16. The retransmission control device according to claim 15, wherein: When the device is a relay station or a mobile station, the first determining device further includes:

a receiving device, configured to receive a receiving status report message from the destination device, where the receiving status indication information indicating whether the destination device correctly receives the target data packet is included;

And an extracting device, configured to extract the receiving status indication information from the receiving status report message;

The second determining means is configured to determine, according to the extracted receiving status indication information, whether the destination device correctly receives the target data packet.

17. A method for assisting automatic packet retransmission in a retransmission auxiliary device of a wireless communication network, comprising the steps of:

B. Retransmit the target data packet received and saved via its different transmission path to its destination device to the destination device that did not correctly receive the target data packet.

18. The method according to claim 17, wherein the step B further comprises the following steps:

- Retransmitting the target data packet received and saved via a different transmission path from the corresponding destination device to the destination device that did not correctly receive the target data packet based on the retransmission indication information from the base station.

The method according to claim 17 or 18, wherein the step B further comprises the following steps:

B1. determining whether the destination device correctly receives the target data packet;

B2. If the destination device fails to correctly receive the target data packet, retransmit the target data packet received and saved via a different transmission path from the destination device to the destination according to the retransmission indication information from the base station. device.

20. A retransmission assistance apparatus for assisting automatic retransmission of a data packet in a retransmission auxiliary device of a wireless communication network, characterized in that it is received and stored via a transmission path different from a destination device corresponding thereto The target data packet is retransmitted to the destination device that did not correctly receive the target data packet.

The retransmission assistance device according to claim 20, wherein the retransmission assistance device is further configured to: - Retransmitting the target data packet received and saved via a different transmission path from the corresponding destination device to the destination device that did not correctly receive the target data packet based on the retransmission indication information from the base station.

The retransmission assistance device according to claim 20 or 21, wherein the retransmission assistance device further comprises:

a third determining device, configured to determine whether the destination device correctly receives the target data packet;

a controlled retransmission device, configured to: when the destination device fails to correctly receive the target data packet, according to the retransmission indication information from the base station, receive the target by using a different transmission path from the destination device The packet is retransmitted to the destination device.