WO2010069095A1

WO2010069095A1 - A self-adapting harq method, apparatus and device

Info

Publication number: WO2010069095A1
Application number: PCT/CN2008/002030
Authority: WO
Inventors: 陈继明; 王伟; 金珊
Original assignee: 上海贝尔股份有限公司; 阿尔卡特朗讯
Priority date: 2008-12-19
Filing date: 2008-12-19
Publication date: 2010-06-24
Also published as: CN102124685B; CN102124685A

Abstract

A self-adapting HARQ method, apparatus and device are provided by the embodiments of this invention. A receiving end receives the data packet, and feeds the different message to the transmitting end self-adaptively according to the detecting condition of the date packet and the reception times. The transmitting end selects a retransmitting scheme self-adaptively according to the retransmitting times and the received feedback message, if it is the first time to retransmit, the data packet is retransmitted to the receiving end by using HARQ technology which is based on STBC, wherein, the retransmitting data packet and the first transmitted data packet form a STBC code word; if it is the second time to retransmit or more times retransmission, the data packet is retransmitted by using HARQ technology which is based on the closed loop MIMO system, wherein, a pre-encode matrix is selected according to the feedback pre-encode matrix index, the data packet that will be transmitting in this time is pre-encoded, then is retransmitted to the receiving end. Wherein, pre-encode matrix is calculated according to the result of unitedly optimizing the received data packet and the data packet that will be received at the next time, and the pre-encoded matrix index is fed back to the transmitting end. By applying the self-adapting HARQ scheme of this invention, the time diversity gain and the total space diversity gain can be obtained, the delay of the system can be reduced, the throughput of the MIMO system can be improved, and it can split the difference between the performance and the complexity.

Description

Method, device and device for adaptive HARO

The present invention relates to communication technologies, and more particularly to a method, apparatus and apparatus for adaptive HARQ. Background technique

In wireless communication systems, MIMO (Multiple Input Multiple Output Antenna Technology) systems are used to provide spatial multiplexing to improve point-to-point link capacity, but due to the deep fading of time-varying channels, large amounts of noise and co-channel interference, the receiving end cannot The transmitted data packets are correctly recovered, so hybrid automatic retransmission HARQ technology is widely used to combine decoding error packets and retransmit packets to enhance the reliability of packet transmission.

A number of HARQ transmission techniques for MIMO systems have been proposed. In the conventional simple repetitive transmission HARQ scheme, the transmitting end transmits at least 2 data packets through two or more antennas. If the transmitted data packet is not correctly received, the received initial transmitted data packet is discarded at the receiving end, and the data packet is simply repeatedly transmitted during the retransmission phase. Table 1 illustrates a packet retransmission method according to a conventional simple HARQ scheme in two transmit antennas and two receive antenna systems, where Si and S ₂ are transmitted data packets. Using this method, the first retransmission completes a repetitive coding process, and a partial diversity gain is obtained accordingly. Since the simple repeat transmission cannot obtain the full diversity gain, the reliability of the retransmission is not enhanced, and the system delay is correspondingly increased.

Table 1

To obtain full diversity gain and a simple retransmission scheme, Reference 1: Elisabeth de Carvalho and Petar Popovski, "Strategies for ARQ in 2 x 2 MIMO Systems," IEEE communications letters, vol. 12, no. 6, June 2008, Pp. 441-443 proposes a STBC-based HARQ retransmission technique in which retransmitted data packets retain the same data, allowing for data symbol changes, data conjugate changes, and antenna assignments. Variety. Obviously, these two retransmissions form an STBC codeword (based on the packet). Table 2 shows the packet retransmission scheme based on STBC-based HARQ in 2 X 2 MIMO systems. Wherein in the first stage Si packets from the transmitting antenna 1 and transmitted from an antenna 2 S _2. If two packets have errors during decoding, in the second phase, the switched antenna assignment, ie -S ₂ * is retransmitted from antenna 1, and Si* is retransmitted from antenna 2, then the receiver receives twice. The data packet constitutes the STBC group, and the packet recovery is completed by STBC decoding. If the error still occurs when the data packet is decoded at this time, the second retransmission still sends the original data packet to form an STBC codeword together with the first retransmitted data packet, and the third retransmission sends the first retransmission. Packets, and so on. Since the full diversity gain and antenna array gain generated by the STBC can combat channel fading, each retransmission can increase the probability of correct reception of the packet. However, if the decoding error is caused by co-channel interference, the correct reception reliability of the retransmission scheme will be reduced.

Table 2

In order to combat the reception errors caused by intra-cell interference and inter-cell interference, a HARQ technology based on a closed-loop MIMO system is proposed to reduce interference. The basic principle is that a precoding matrix is calculated according to the received channel information and the precoding matrix information is fed back. For each retransmission, the transmitting end pre-codes the retransmitted data using the feedback precoding matrix to obtain the diversity gain of the retransmission; at the same time, the receiving end, according to the given retransmission combining type, such as Chase combining scheme and incremental redundancy The remaining combining schemes and the like to maximize the use of the received multiple MIMO signals. Reference 2: Byung-Jae Kwak, Dong Seung Kwon, et. AL, "HARQ in a Closed Loop MIMO System", ETRI, IEEE C802.16m-08/440 proposes a HARQ scheme for a closed-loop MIMO system, in which, Each time a retransmission, a linear precoding matrix is selected to precode the transmitted data packet, and the retransmitted data is combined at the receiving end to obtain a higher combining gain to improve the decoding probability. FIG. 1 is a schematic diagram showing the implementation structure of a closed-loop MIMO system HARQ scheme, where S is a packet vector and WL is a precoding matrix. The received signal of the second retransmission is H, which is the MIMO channel matrix of the first transmission, and L is the maximum number of transmissions, n For noise. After L - l retransmissions, the data received by the receiving end multiple times can be cascaded as:

After the symbol level merging process, the combining gain is obtained to reduce intra-cell interference and inter-area interference, and the probability of corresponding correct reception of the data packet increases. However, due to the time-varying characteristics of the channel, the precoding matrix W is calculated according to the channel estimation for each retransmission, and the computational complexity of the scheme is too high to be applied in an actual system. Summary of the invention

In order to solve the above disadvantages in the prior art, the present invention proposes a new adaptive HARQ method, apparatus and apparatus. The receiving end receives the data packet, and adaptively feeds back different messages to the transmitting end according to the data packet detection situation and the number of receiving times. The transmitting end adaptively selects a retransmission scheme according to the number of retransmissions and the received feedback message, and if it is the first retransmission, retransmits the data packet to the receiving end by using the STBC-based HARQ technology, and the retransmission data packet and the The data packets sent once form one STBC codeword; if it is the second and higher retransmissions, the HARQ technology based on the closed-loop MIMO system is selected to retransmit the data packet, and the precoding matrix is selected according to the feedback precoding matrix index. The pre-encoded data packet of this transmission is retransmitted to the receiving end. The precoding matrix is calculated by the receiving end jointly optimized according to the received data packet and the data packet to be received by the next retransmission, and the precoding matrix index is fed back to the transmitting end.

Further, the present invention also proposes a joint optimization algorithm, where the receiving end cooperates with the channel state information when transmitting the previous data packets and the channel diversity of the current data packet transmission to achieve greater diversity gain to combat intra-cell and inter-cell Interference. Specifically, the optimized precoding matrix is calculated based on the maximum SNR criterion. The data packet that has been received and the next retransmission will be combined for symbol level combining, and the precoding matrix is calculated after the maximum symbol level is combined and the output signal is compared to the S NR criterion.

The invention further optimizes the symbol level combination of the receiving end, that is, the first few times After receiving the decoded data packet, the received data packet is separately symbol-level merged with the data packet received this time, and the symbol level is combined and jointly decoded. Similarly, the optimization of symbol-level merging can also be applied to the joint optimization algorithm, that is, after the data packets that have been received are respectively erased and the data packets that have been decoded correctly are combined with the data packets that are received by the next retransmission, the symbol-level merging is combined to maximize The precoding matrix is calculated under the criterion of output level signal ratio combining after symbol level combining.

In addition, in the present invention, selective retransmission can also be applied, that is, the receiving end feeds back the decoding error information to the transmitting end according to the decoding situation, and the transmitting end selects the decoded error data packet as the retransmission data packet according to the decoding error information, and Sent with new packets to increase port throughput.

Specifically, according to an embodiment of the present invention, an adaptive HARQ method is provided. The method includes: sending, by a sending end, a data packet; receiving, by a receiving end, a data packet, determining a number of times of receiving, and determining a data packet detecting method according to the number of times of receiving, And sending different messages to the sending end according to the data packet detection result and the receiving times; the sending end receives the feedback message, and determines the retransmission mode and the retransmission content according to the feedback message and the number of retransmissions.

According to an optional embodiment of the present invention, the receiving end determines the number of times of receiving, and determining the data packet detecting method according to the number of receiving times includes: if the number of receiving times is 0, directly decoding the received data packet; otherwise, the data packet received before and the current Packets received several times are jointly decoded after symbol level merging.

According to an optional embodiment of the present invention, the data packet received this time and the data packet received in the previous several times are combined and decoded at the symbol level, which means that the data packets received in the previous several times are respectively decoded and decoded correctly. After the data packet, it is combined with the data packet received this time, and the symbol level is combined and decoded.

According to an optional embodiment of the present invention, feeding different messages to the sending end according to the data packet detection result and the receiving number of times includes:

If the packet is decoded correctly, an ACK (acknowledgement) message is fed back to the sender, and the number of receptions is set to 0; if the packet is decoded incorrectly, it is judged

If the number of receptions reaches a set value, a NAK (Negative Acknowledgement) message is fed back to the sender, and the number of receptions is set to 0; If the number of receptions is less than one set value, the received data packet is stored, and the number of times of reception will be 1 and

If the number of receptions is 1, the receiver sends a NAK message to the sender; if the number of receptions is greater than 1, a precoding matrix is calculated and the precoding matrix index and a NAK message are fed back to the sender.

According to an optional embodiment of the present invention, the data packet detection result and the number of receptions further include if the data packet decoding error is less than a set value, and the receiving end further sends a data packet decoding error message to the transmitting end.

According to an optional embodiment of the present invention, the sending end determines the retransmission mode and the retransmission content according to the feedback message and the number of retransmissions, including:

If an ACK message is received, a new data packet is sent, and the number of retransmissions is set to 0. If a NAK message is received, the number of retransmissions is incremented by one and the number of retransmissions is determined: If the number of retransmissions is 1, the first transmission is performed. The data packet is used as the data packet of the current transmission, and the data packet is retransmitted to the receiving end by using the STBC-based HARQ technology, and the retransmitted data packet and the first transmitted data packet form an STBC codeword;

If the number of retransmissions is not greater than a system setting value, the data packet transmitted for the first time is used as the data packet transmitted this time, and the precoding matrix is selected according to the precoding matrix index in the feedback message, and the data packet for the current transmission is selected. Perform precoding and retransmit to the receiving end; if the number of retransmissions is greater than a system setting value, send a new data packet and set the number of retransmissions to 0.

According to an optional embodiment of the present invention, the data packet transmitted for the first time is used as the data packet transmitted this time, and the data packet that needs to be retransmitted is selected according to the data packet error information and used as the data packet for the current transmission.

According to an alternative embodiment of the invention, the data packet transmitted this time further comprises a new data packet.

According to an optional embodiment of the present invention, the retransmission of the data packet by the transmitting end by the STBC-based HARQ technology refers to the coherence of the transmitting end transmitting the initial data packet.

According to an optional embodiment of the present invention, the retransmission of the data packet by the transmitting end by the STBC-based HARQ technology refers to the orthogonal sequence corresponding to the sending of the initial data packet by the transmitting end. According to an optional embodiment of the present invention, the calculating a precoding matrix is based on a maximum SNR criterion, and calculating an optimized precoding matrix.

According to an optional embodiment of the present invention, the data packet that has been received is combined with the data packet to be received by the next retransmission for symbol level combining, and the pre-calculation is calculated under the criterion of outputting the signal-to-noise ratio SNR after maximizing the symbol level combining. Encoding matrix.

According to an optional embodiment of the present invention, combining the already received data packet with the next retransmission of the received data packet for symbol level merging means that the already received data packet is respectively erased and decoded after the correct data packet is decoded. The secondary retransmission combines the received packets for symbol level merging.

According to an alternative embodiment of the invention, the set value refers to the maximum number of retransmissions set by the system.

According to an embodiment of the present invention, an adaptive HARQ retransmission method is provided. The method includes: a sender sends a data packet, a sender receives a feedback message, and determines a retransmission mode and a retransmission content according to the feedback message and the number of retransmissions. .

According to an optional embodiment of the present invention, further, the data packet transmitted for the first time is used as the data packet transmitted this time, and the data packet that needs to be retransmitted is selected according to the data packet error information in the feedback message and is used as this time. The transmitted data packet. According to an alternative embodiment of the invention, the data packet transmitted this time further comprises a new data packet.

According to an optional embodiment of the present invention, the retransmission of the data packet by the transmitting end by the STBC-based HARQ technology refers to the coherence of the data packet that the transmitting end needs to transmit.

According to an optional embodiment of the present invention, the transmitting end retransmits the data packet by using the STBC-based HARQ technology, where the transmitting end sends the orthogonal sequence corresponding to the data packet to be transmitted.

According to an embodiment of the present invention, an adaptive HARQ receiving feedback method is provided. The method includes: receiving, by a receiving end, the data packet, determining a number of times of receiving, determining a data packet detection according to the number of times of receiving, and detecting a result according to the data packet. The number of receptions feeds back different messages to the sender.

According to an optional embodiment of the present invention, the receiving end determines the number of times of receiving, and determining the data packet detection according to the number of receiving includes: if the number of receiving times is 0, directly decoding the received data packet; otherwise, the data packet received before and the first few The received data packets are jointly decoded after symbol level combining.

In an optional embodiment of the present invention, combining the data packet received this time and the data packet received in the previous several times after being combined at the symbol level refers to erasing the data packet received in the previous several times and decoding the correct data packet. Then, the data packets received this time are combined at the symbol level, and the symbol level is combined and decoded.

If the data packet is decoded correctly, an ACK message is fed back to the sender, and the number of receptions is set to 0;

If the packet is decoded incorrectly, judge

If the number of receptions reaches a set value, a NAK message is fed back to the sender, and the number of receptions is set to 0;

If the number of receptions is less than one set value, the received data packet will be stored, and the number of times will be received 1 and

If the number of receptions is 1, the receiving end sends a NAK message to the sending end; If the number of receptions is greater than 1, a precoding matrix is calculated and the precoding matrix index and an N AK message are fed back to the transmitting end.

According to an optional embodiment of the present invention, different messages are fed back to the transmitting end according to the data packet detection result and the number of receptions, and further includes: if the data packet is decoded incorrectly, the receiving number is less than a set value, and the receiving end further sends a data packet decoding error. Information to the sender.

According to an alternative embodiment of the invention, calculating a precoding matrix is based on a maximum SNR criterion and computing an optimized precoding matrix.

According to an embodiment of the present invention, an apparatus for retransmitting an adaptive HARQ is provided, the apparatus comprising: a sending unit, configured to send a data packet, a receiving unit, configured to receive a feedback message, and a determining unit, configured to determine a feedback message and The number of retransmissions; the processing unit is configured to determine a retransmission mode and a retransmission content according to the feedback message and the number of retransmissions.

According to an optional embodiment of the present invention, determining the retransmission mode and retransmitting the content according to the feedback message and the number of retransmissions includes:

If the number of retransmissions is not greater than a system setting, the packet will be transmitted for the first time. As the data packet of the current transmission, the precoding matrix is selected according to the precoding matrix index in the feedback message, and the data packet transmitted in this time is precoded and then retransmitted to the receiving end;

If the number of retransmissions is greater than one system setting, send a new packet and set the number of retransmissions to 0.

According to an optional embodiment of the present invention, if the NAK message is received, the first transmitted data packet is used as the data packet transmitted this time, and the data packet that needs to be retransmitted is selected according to the data packet error information in the feedback message. As the data packet for this transmission.

In accordance with an alternative embodiment of the present invention, retransmitting a data packet with a STBC based HARQ technique refers to transmitting a common packet of data packets that need to be transmitted.

According to an alternative embodiment of the present invention, retransmitting a data packet based on the STBC-based HARQ technique refers to transmitting an orthogonal sequence corresponding to a data packet to be transmitted.

According to an embodiment of the present invention, an adaptive HARQ receiving feedback apparatus is provided, the apparatus comprising: a receiving unit, configured to receive the data packet; a determining unit, configured to determine a receiving times and a data packet decoding situation; a detecting unit, configured to determine a packet detection according to the number of times of receiving; and a feedback unit, configured to feed back different messages according to the packet detection result and the number of times of receiving.

According to an optional embodiment of the present invention, determining the data packet detection according to the number of receptions includes: if the number of receptions is 0, directly decoding the received data packet; otherwise, the data packet received this time and the data packet received in the previous time are The symbol level is combined and decoded.

According to an optional embodiment of the present invention, combining the data packet received this time and the data packet received in the previous several times after being combined at the symbol level means decoding the data packet received in the previous several times to decode the correct data packet. Then, the data packets received this time are combined at the symbol level, and the symbol level is combined and decoded.

According to an optional embodiment of the present invention, different messages according to the data packet detection result and the received number of times of feedback include:

If the data packet is decoded correctly, an ACK message is fed back, and the number of receptions is set to 0; If the packet is decoded incorrectly, judge

If the number of receptions reaches a set value, a NAK message is fed back, and the number of receptions is set to 0;

If the number of receptions is less than a set value, the received data packet is stored, and the number of receptions is incremented by one, and

If the number of receptions is 1, the receiving end sends a NAK message;

If the number of receptions is greater than 1, a precoding matrix is calculated and the precoding matrix index and a NAK message are fed back.

According to an optional embodiment of the present invention, feeding back different messages according to the number of receptions further includes transmitting a packet decoding error message if the packet decoding error is less than a set value.

According to an embodiment of the present invention, there is provided a network side device employing adaptive HARQ, including the above-described adaptive HARQ retransmission device.

According to an embodiment of the present invention, there is provided a terminal device employing adaptive HARQ, comprising the above-described adaptive HARQ retransmission device.

According to an embodiment of the present invention, a network end device using adaptive HARQ is provided, including a receiving feedback device of the adaptive HARQ.

According to an embodiment of the present invention, an end using adaptive HARQ is provided The end device includes the above-mentioned adaptive HARQ receiving feedback device.

By using the method, device and device provided by the present invention, the HARQ technology is adaptively selected according to the number of retransmissions, and the precoding matrix weights are jointly optimized, so that the time diversity gain and the full space diversity gain are obtained by retransmission, which can reduce system delay and improve The throughput of MIMO systems, and a good compromise between performance and complexity. BRIEF DESCRIPTION OF THE DRAWINGS Other objects and effects of the present invention will become more apparent and appreciated from the following description of the appended claims.

Figure 1 shows a schematic block diagram of a HARQ scheme for a closed-loop MIMO system.

FIG. 2 is a schematic flowchart of a HARQ scheme according to an embodiment of the present invention, where the maximum number of retransmissions is 2.

FIG. 3 is a schematic flow chart of a HARQ scheme according to an embodiment of the present invention, with packet error information.

Fig. 4 shows a schematic flow chart of a HARQ retransmission method employing an embodiment of the present invention.

FIG. 5 shows a schematic flow chart of a HARQ reception feedback method according to an embodiment of the present invention.

Fig. 6 is a block diagram showing the structure of a retransmission apparatus according to an embodiment of the present invention.

Fig. 7 is a block diagram showing the structure of a receiving feedback device according to an embodiment of the present invention.

Figure 8 is a diagram showing the results of throughput simulation based on a 2 2 MIMO system in accordance with the present invention.

Figure 9 is a diagram showing the simulation result of the average number of transmissions based on the 2 X 2 MIMO system according to the present invention.

In all of the above figures, the same reference numerals are used to indicate the same, similar or corresponding features or functions. detailed description

Embodiments of the present invention will be specifically described below with reference to the accompanying drawings.

Embodiments of the present invention are implemented based on a MIMO system. For the description, a 2 x 2 antenna system is taken as an example, but the present invention is not limited thereto. Those skilled in the art will appreciate that MIMO systems have many alternative antenna configurations and can be applied to the present invention. The above settings are only examples of ') and birth instructions.

In a MIMO system, if a decoding error occurs at the receiving end, it is generally caused by three reasons: (1) a large amount of noise (2) deep fading of the time-varying channel (3) severe co-channel interference. When HARQ technology is applied to improve the reliability of data packet transmission, the choice of retransmission scheme needs to be adaptively selected according to different error reasons. When a NAK message is received at the transmitting end of the MIMO system, the transmitting end knows that the transmitted data packet is corrupted by noise and channel deep fading, or noise and co-channel interference, or the above three causes together to cause a decoding error.

In order to reduce the implementation complexity, in the present invention, the first retransmission selects a STBC-based HARQ scheme to combat channel deep fading, that is, space-time coding of the initially transmitted data.

If an error occurs after the initial transmission and the space-time decoding of the first retransmission, the MI MO channel suffers from severe co-channel interference. At this time, the HARQ scheme of a closed-loop MIMO system is selected.

The next retransmission still selects the HARQ scheme of the closed-loop MIMO system until the receiver decodes correctly or reaches the maximum number of retransmissions set by the system.

That is to say, the present invention proposes an adaptive selection retransmission scheme according to the number of retransmissions on the basis of analyzing the reason for the decoding error of the receiving end in the MIMO system, and the first retransmission selects the HARQ retransmission technique based on STBC, wherein The transmitted data packet retains the same data, while allowing for changes in data symbols, data conjugate changes, and antenna assignment changes. These two retransmissions form an STBC codeword (based on the data packet). Since the full diversity gain and antenna array gain generated by the STBC can combat channel fading, each retransmission can increase the probability of correct reception of the data packet. The second and subsequent retransmissions use the HARQ scheme of the closed-loop MIMO system. Each time the retransmission is performed, the receiving end estimates the channel state based on the received signal. And calculating a precoding matrix according to the channel state information, and feeding back the precoding matrix index to the transmitting end, and the sending end selects a precoding matrix according to the received precoding matrix index, and precodes the retransmitted data. Then, it is retransmitted to the receiving end to make the retransmission obtain the diversity gain. At the same time, the receiving end combines the data of multiple retransmissions according to the given retransmission combining type, such as Chase combining scheme and incremental redundancy combining scheme. High combining gain to improve decoding probability.

Further, the present invention also proposes a joint optimization algorithm, where the receiving end cooperates with the channel state information when transmitting the previous data packets and the channel diversity of the current data packet transmission to achieve greater diversity gain to combat intra-cell and inter-cell Interference. Specifically, the optimized precoding matrix is calculated based on the maximum SNR criterion. The data packet that has been received and the next retransmission will be combined for symbol level combining, and the precoding matrix is calculated after the maximum symbol level is combined and the output signal is compared to the SNR criterion.

The present invention further optimizes the symbol level combination of the receiving end, that is, the data packets received by the previous several times are respectively decoded to decode the correct data packet, and then the received data packets are symbol-level merged, and the symbol level is combined and jointly decoded. Similarly, the optimization of symbol-level merging can also be applied to the joint optimization algorithm, that is, after the data packets that have been received are respectively erased and the data packets that have been decoded correctly are combined with the data packets that are received by the next retransmission, the symbol-level merging is combined to maximize The precoding matrix is calculated under the criterion of output level signal ratio combining after symbol level combining.

The working process of the adaptive HARQ will be specifically described with reference to FIG. 2 . In this embodiment, the maximum number of retransmissions is set to two. In addition, in order to reduce the overhead of the precoding matrix feedback, this embodiment adopts a codebook-based form to feed back a precoding matrix, that is, a transceiver group pre-defining a finite length code group, and the receiving end is based on the calculated precoding matrix, and then An index value representing the precoding matrix is found in the codebook and fed back to the transmitting end, and the transmitting end finds a corresponding precoding matrix in the codebook according to the received precoding matrix. Line precoding to eliminate co-channel interference. When the system is initialized, the receiving end and the transmitting end respectively initialize the number of receptions and the number of retransmissions to 0, set a set value, that is, the maximum number of retransmissions is 2, and configure the codebook.

At step S201, the transmitting end transmits an initial data packet (S _l5 S ₂ ).

At step S211, the receiving end receives the data packet, and the received signal can be expressed as:

Where ^'' / = 1, ² is the channel coefficient between the receiving antenna i and the transmitting antenna j.

The receiving end judges that the number of receptions is 0, directly decodes the received data, assuming a decoding error, adds 1 to the received number, stores the received data, and feeds back a NAK message.

In step S202, the sender receives the NAK message, adds 1 to the number of retransmissions, and determines that it is the first retransmission. Then, the retransmission is performed by using the STBC-based HARQ technology, and the retransmission packet is (-S ₂ *, Si*).

At step S212, the signal received by the receiving end is expressed as follows:

When it is judged that the number of receptions is 1, the formulas (3) and (4) are combined to obtain

Based on equation (5), joint detection of received signals is performed: symbol level combining and decoding. Assuming a decoding error, and then judging that the number of receptions is 1, less than the maximum number of retransmissions 2, the number of receptions is incremented by one, storing the received data, and calculating the precoding matrix: assuming the next retransmission, that is, the received signal after the second retransmission Can be expressed as follows:

Where 1 indicates the number of transmissions, 1 = 3 at this time, W indicates the precoding matrix, and ^W "" ⁼ is the precoding weighting coefficient when the HARQ scheme of closed-loop MIMO is used for the first time.

Combine equations (5) and (6) to get:

Its simplified expression is

r = Hs + n (8) fi is the combined channel for multiple transmissions, S is the combined noise after multiple transmissions, _S is the transmitted multi-path packet, and r is the received signal after multiple transmissions 1. Symbol level detection The combined SNR can be calculated according to formula (7), expressed as a function of W, ie

Where ^g '' is the row vector of the minimum mean square error MMSE weight, expressed as

= [gi,g ₂ ] ^r (10) denotes the transpose of the vector, [·] ^-1 denotes the inverse matrix, (·)" denotes the conjugate transpose of the vector, I denotes the identity matrix, and ^£ 'is S The i-th column vector. Based on the maximum SNR criterion, an optimized precoding matrix is calculated, ie

= arg max x(h _; , h ₂ , hj ³⁾ , h ⁽ ₂ ³⁾ ; W ^{1) )

w(i) ( 11 ) where argmax represents the value of W(l) when γ is maximized, and γ represents the SNR of the combined output at the receiving end,

Hl ⁼ [ ^/Z U ' ^2 ] ' ^h 2 = I l , ] , hi ³⁾ = [/ΐ,

The receiving end finds the corresponding precoding matrix index in the code table according to the calculated precoding matrix, and feeds the precoding matrix index together with a ΝΑΚ message to the transmitting end.

At step S203, the transmitting end receives the precoding matrix index of the ΝΑΚ message and the feedback, and the number of retransmissions is incremented by one, and the second retransmission is determined, and the corresponding precoding is selected in the codebook according to the precoding matrix index of the feedback message. The matrix performs precoding matrix on the retransmitted data packet and sends it to the receiving end.

At step S213, the signal received by the receiving end is represented as shown in equation (7). On the basis of equation (7), the received signal is symbol-level merged and decoded. Assuming the decoding is correct, the number of receptions is set to 0, and an ACK message is fed back to the sender. At step S204, the transmitting end receives the ACK message, sets the number of retransmissions to 0, and transmits a new data packet.

Without loss of generality, FIG. 3 shows the operation of adaptive HARQ with a maximum number of retransmissions of L, L>2, in accordance with an embodiment of the present invention. Also, in the embodiment shown in Fig. 3, the symbol level combining optimization at the receiving end and the selective retransmission based on the decoding error information are also described in detail. Also, in order to reduce the overhead of precoding matrix feedback, this embodiment uses a codebook based form feedback feedback precoding matrix. When the system is initialized, the receiving end and the transmitting end respectively initialize the number of receptions and the number of retransmissions to 0, set a set value, that is, the maximum number of retransmissions is L, and configure the codebook.

At step S301, the transmitting end transmits an initial data packet (St, S ₂ ).

At step S31 1, the receiving end receives the data packet, and the received signal is expressed as equation (3).

The receiving end judges that the number of receptions is 0, directly detects and decodes the received data, assuming 8 decoding errors, S ₂ decoding is correct, adding 1 to the received number, storing the received data, and feeding back a NAK message and packet error information.

At step S302, the sender receives the NAK message, increments the number of retransmissions, and determines that it is the first retransmission. According to the received packet error information, only retransmission will be performed, and (-S ₃ *, The transmitted data packet is shown in Table 3.

table 3

At step S312, the signal received by the receiving end is expressed as follows

n

When it is judged that the number of receptions is 1, the data of the first reception and the current reception is symbol-level combined, and the first received signal is cancelled according to the first packet error information, and the correct data packet S _{2 is} decoded, that is, the formula /z ₂ in (3), A _{22 is} set to 0. That is, formula (3) is modified to:

[η,

V h"2, 1

Combine the formulas ( 12 ) and ( 13 ) to get the formula ( 14 ) (14)

Joint detection of received signals, symbol level combining, and decoding. Assuming that the Si decoding is wrong, then it is judged that the number of receptions is 1, less than the maximum number of retransmissions L, and the number of receptions is incremented by 1, the received data is stored, and the precoding matrix is calculated. The calculation of the precoding matrix is as described in step S212, except that the formula (7) is modified to the following formula (15):

The first time, the second received data packet is decoded and the correct data packet is decoded and then symbol level merged. According to formula (15), the precoding matrix under the maximum SNR is

W ^(,) = argmax^(h _I ,h ₂ ,hj ³⁾ ,h^ ³⁾ ;W ⁽¹⁾ )

w('> ( 16) where argmax represents the value of W(l) when γ is maximal, and γ represents the SNR of the combined output at the receiving end.

h, is o. Connect

The code matrix index feeds back the precoding matrix index, the NAK message, and the packet decoding error information to the transmitting end.

In step S303, the transmitting end receives the NAK message and the feedback precoding matrix index, and the number of retransmissions is increased by 1, and it is determined that the second retransmission is less than the maximum retransmission number L, and the selection is only performed according to the received packet error information. Pass, and (S!, S ₄ ) as the transmitted data packet, where S ₄ is the new data packet. Then, the corresponding precoding matrix is selected in the codebook according to the precoding matrix index of the feedback message, and the retransmission data packet is precoded and sent to the receiving end.

At step S313, the number of receptions of the receiving end is (L-1), and the processing is similar to the description of step S312. At this point, the formula ( 11 ) is modified to:

W ⁽ⁱ - ²⁾ = argmax (h _n h ₂ , hi ³ \h ⁽ ₂ ³ .^hj ⁱ \h^\w ⁽ ^--^W ^{i - ³⁾ ; ⁽ⁱ ^)

w(") (17) Where argmax represents the value of W ^(L - ²⁾ when γ is maximized, and γ represents the SNR of the combined output of the receiver, L represents the maximum number of transmissions, ^h ' ⁼ lA, 'A ₂ ], ^h ) ⁼ [3⁄4 ), )], i=l, 2. The weight corresponding to the correct data decoded by each retransmission also corresponds to 0.

At step S304, the processing of the transmitting end is similar to that described in step S303.

At step S3 14, the receiving end receives the data packet and decodes it after optimizing the symbol level merging process, similar to the corresponding process of step S312, assuming a decoding error, determining that the number of receptions is L, and the maximum number of retransmissions is reached. The number of receptions is set to 0 and a NAK message is fed back.

At step S305, the sender receives a NAK message, determines that the number of retransmissions is L, has reached the set maximum number of retransmissions, and the sender sends a new data packet.

4 is a schematic flow chart of a HARQ retransmission method in accordance with an embodiment of the present invention.

At step S401, the sender sets the maximum number of retransmissions. Set the number of retransmissions to 0 and set the codebook.

At step S402, the transmitting end transmits a data packet. At step S403, feedback information is received.

At step S404, it is determined whether an ACK message is received or the number of retransmissions reaches the set maximum number of retransmissions. If either condition is satisfied, the process proceeds to step S405, and the number of retransmissions is set to 0. At step S406, a new one is selected. The data packet returns to the step S402 to transmit a new data packet. If the NAK message is received and the number of retransmissions is less than the set maximum number of retransmissions, the process proceeds to step S407, and the retransmission data packet is selected. According to an embodiment of the present invention, the retransmission data packet may be an initial transmission data packet. According to another embodiment of the present invention, the feedback message includes a data packet decoding error information, and the decoding error is selected according to the data packet decoding error information. The data packet is used as a retransmitted data packet and is used together with the new data packet as the data packet for this retransmission.

At step S408, the number of retransmissions is incremented by one. At step S409, it is determined whether the number of retransmissions is 1, and if yes, proceeding to step S410, retransmitting the selected retransmission data packet in a HARQ manner based on STBC, and returning to step S402 to transmit a new data packet; If the number of transmissions is not 1, the process proceeds to step S41 1. The corresponding precoding matrix is selected according to the precoding matrix index in the feedback message, and then, at step S412, the selected data packet is retransmitted by the closed loop MIMO based HARQ method, which is about to be selected. Retransmitted data The packet is precoded and then returned to the new data packet at step S402.

FIG. 5 is a schematic flow chart of a HARQ reception feedback method according to an embodiment of the present invention.

At step S501, the receiving end sets the maximum number of retransmissions. Initialize the number of receptions to 0 and set the codebook.

At step S502, a data packet is received.

At step S503, it is determined whether the number of receptions is 0. If yes, it indicates that the current reception is the first reception, and the received data is directly detected and decoded; if not, it indicates that the reception is receiving retransmission data. The packet will be jointly detected by the received data packet. According to an embodiment of the present invention, the joint detection is to combine the data received this time and the data received in the previous several times at the symbol level to obtain a combined gain, and reduce intra-cell interference and interval interference. According to another embodiment of the present invention, an optimized symbol level merging process is employed, that is, the packets received in the previous few times are respectively erased to decode the correct data packet and merged with the data packet received this time at the symbol level. How to eliminate It has been explained in detail, and will not be repeated here.

After decoding, the process proceeds to step S506, where it is judged whether the decoding is correct. If the decoding is correct, the process proceeds to step S508, the number of receptions is set to 0 and an ACK message is transmitted, and then returns to step S502 to receive the data packet. If the decoding is wrong, the process proceeds to step S509, where the number of receptions is further determined. If the number of receptions is equal to the set value, that is, the maximum number of retransmissions is reached, then the process proceeds to step S510, the NAK message is sent and the number of receptions is set to 0, and then the process returns to step S502 to receive data. package.

If the number of receptions is equal to 1, the process proceeds to step S51 1 , the number of receptions is incremented by 1, and the data received this time is stored, and the process proceeds to step S512, and a NAK message and a packet error message are transmitted. After step S512 is performed, the process returns to step S502 to receive the data packet.

If the number of receptions is greater than 1 and less than the set maximum number of retransmissions, proceeding to step S513, adding 1 to the number of receptions, storing the data received this time, and proceeding to step S514, the data to be received and the data to be received next time retransmission Joint optimization, calculating the precoding matrix of the next retransmission under the criterion of maximum SNR; another implementation according to the present invention For example, in the process of joint optimization calculation of the precoding matrix, the optimized symbol level merging process is adopted, that is, the data packets that have been received are respectively decoded to decode the correct data packet, and then the data packets to be received are merged at the symbol level with the next retransmission. The process of how to jointly optimize the calculation of the precoding matrix and the use of the optimized symbol level merging process has been described in detail above, and will not be described here. Next, proceeding to step S515, the NAK message is transmitted, the matrix index and the packet error information are precoded, and then the process returns to step S502 to receive the data packet.

According to another embodiment of the present invention, in the processing of step S512 and step S515, the packet error message may not be transmitted.

In the embodiment of the present invention, the retransmission device 600 is configured to transmit/retransmit a data packet, and includes a receiving unit 601, a determining unit 602, a processing unit 603, and a transmitting unit 604.

Specifically, the receiving unit 601 may be configured to acquire a feedback message, and the feedback message may be {ACK message}, {NAK message}, {NAK message, packet decoding error information}, {NAK message, precoding matrix index}, or {NAK message, precoding matrix index, packet decoding error message}. The ACK message or the NAK message is input to the judging unit 602. The packet decoding error information and the precoding matrix index are input to the processing unit 603, the former for selecting the retransmission data packet, and the latter for precoding the retransmission data packet in the HARQ mode of the closed loop MIMO.

The judging unit judges that the feedback message is an ACK message or a NAK message, and judges the number of retransmissions, and the judgment result is input to the processing unit 603.

The processing unit 603 is configured to adaptively select a retransmission mode according to the determination result. If it is an ACK message, the processing unit 603 selects a new data packet and inputs it to the sending unit 604 to send; if it is a NAK message, further determines the result according to the number of retransmissions. If the number of retransmissions has reached the set maximum number of retransmissions, the processing unit 603 selects a new data packet and inputs it to the sending unit 604 for transmission; if it is a NAK message and the number of retransmissions is 1 is less than the maximum number of retransmissions, the processing unit 603 Adapting and selecting the STBC-based HARQ mode to process the retransmission data packet and inputting it to the sending unit 604 for data packet retransmission; if it is a NAK message and the number of retransmissions is greater than 1 and less than the maximum number of retransmissions, the processing unit 603 The adaptively selecting the closed-loop MIMO-based HARQ method processes the retransmission data packet and inputs it to the transmitting unit 604 for packet retransmission. The specific process of processing the retransmission data packet and the HARQ mode based on the closed loop MIMO based on the STBC-based HARQ method has been described in detail above, and will not be described herein.

Transmitting unit 604 is configured to transmit a data packet or retransmit a data packet.

In the embodiment of the present invention, the receiving feedback device 700 is configured to receive a data packet and perform message feedback according to the packet detection, and includes a receiving unit 701, a determining unit 702, a detecting unit 703, and a feedback unit 704.

Specifically, the receiving unit 701 is configured to receive a data packet. The received packet is input to the detecting unit 703.

The judging unit 702 is configured to judge the number of receptions and judge the packet detection result. First, the number of receptions is judged, and the result of the judgment of the number of receptions is input to the detecting unit 703.

The detecting unit 703 is configured to perform packet detection based on the number of receptions, and if the number of receptions is 0, the detecting unit 703 performs direct packet detection, and if the number of receptions is greater than 0, performs packet joint detection. According to an embodiment of the present invention, the joint detection is to combine the data received this time and the data received in the previous several times at the symbol level to obtain a combined gain, and reduce intra-cell interference and interval interference. According to another embodiment of the present invention, an optimized symbol level merging process is employed, in which the previously received packets are respectively decoded to decode the correct data packet and merged with the currently received data packet at the symbol level. The specific process of how to eliminate the correct data packet and perform symbol level merging and joint decoding has been described in detail above, and will not be mentioned here.

The result of the packet inspection is further input to the judging unit, and the judging unit inputs the packet detection result judgment and the reception count judgment to the feedback unit 704.

The feedback unit 704 is configured to generate a feedback message and send a feedback message according to the number of receptions and the packet detection result. Specifically, the feedback message may be {ACK message}, {NAK message}, {NAK message, packet decoding error information}, {NAK message, precoding matrix index}, or {NAK message, precoding matrix index, data packet Decoding error letter Interest rate}. If the input unit 702 determines that the input packet is correctly decoded, the feedback unit 704 generates an ACK message and transmits the message, and the determining unit 702 sets the number of times of reception to 0. If the input packet decodes the error message, it further processes the result according to the number of received times. If the number of receptions reaches the set value, that is, the maximum number of retransmissions, the feedback unit 704 generates a NAK message and feeds back the NAK message; the determining unit 702 sets the number of receptions to 0, and if it is determined that the number of receptions is equal to 1, the determining unit 702 adds 1 to the number of receptions. The detecting unit 703 stores the data received this time, and the feedback unit 704 generates a NAK message and a packet error message and feeds back the NAK message and the packet error message. If the number of receptions is greater than 1 and less than the set maximum number of retransmissions, the determining unit 702 adds 1 to the number of receptions, the detecting unit 703 stores the data received this time, and the feedback unit 704 calculates a precoding matrix and generates the precoding matrix. Feedback messages for indexes, NAK messages, and packet error messages are fed back. The calculation process of the precoding matrix has been described in detail above and will not be described here.

In accordance with another embodiment of the present invention, a packet error message may also not be generated at feedback unit 704.

Figures (8) and (9) give simulation results of throughput simulation and average transmission times based on 2 X 2 MIMO system according to the present invention, respectively, and compare with system throughput and average transmission times using STBC-based HARQ. . The simulation parameters are shown in Table 4, Table 4

Simulation parameter parameter value

Carrier frequency 2.5GHz

Bandwidth 10MHz

Modulation code 16QAM-1/2

Channel coding convolution Turbo code

FFT length 1024

Channel model 3 GPP spatial channel model non-line-of-sight propagation

(3GPP SCM urban micro NLOS ) channel estimation ideal channel estimation

Movement speed 3km/h

M maximum retransmission times 3 According to the figure (8) and (9), it can be seen that, compared with the STBC-based HARQ scheme, with the adaptive HARQ of the present invention, the system throughput is increased, the average number of transmissions is reduced, and the system delay can be reduced. In addition, compared to the closed-loop ΜΙΜΟ-based HARQ system, the complexity is relatively reduced due to the first STBC-based HARQ retransmission. Therefore, the present invention has a good compromise between performance and complexity. Therefore, the present invention can achieve a better compromise between performance and complexity.

The invention can be implemented in hardware, software, firmware, and combinations thereof. Those skilled in the art will recognize that the present invention may also be embodied in a computer program product disposed on a signal bearing medium for use by any suitable data processing system. Such signal bearing media can be a transmission media or a recordable media for machine readable information, including magnetic media, optical media or other suitable media. Examples of recordable media include: magnetic or floppy disks in a hard disk drive, optical disks for optical drives, magnetic tape, and other media as will occur to those of skill in the art. Those skilled in the art will recognize that any communication device having suitable programming means will be capable of performing the steps of the inventive method as embodied in the program product.

It will be understood from the above description that modifications and variations of the various embodiments of the invention may be made without departing from the spirit of the invention. The description in the specification is for illustrative purposes only and should not be considered as limiting. The scope of the invention is limited only by the claims.

Claims

Claim

An adaptive HARQ method, the method comprising:

The sender sends a data packet;

Receiving, by the receiving end, the data packet;

The receiving end determines the number of times of receiving, and determines a data packet detecting method according to the number of receiving times; and feeds different messages to the transmitting end according to the data packet detection result and the number of receiving times;

The sender receives the feedback message, and determines the retransmission mode and the retransmission content according to the feedback message and the number of retransmissions.

2. The method according to claim 1, wherein

The receiving end determines the number of times of receiving, and the method for detecting the data packet according to the number of times of receiving includes: if the number of receiving times is 0, directly decoding the received data packet; otherwise, the data packet received this time and the data received in the previous several times are in the symbol The level is merged and combined for decoding.

3. The method according to claim 2, wherein the combining the data packet received this time and the data packet received in the previous several times after being combined at the symbol level refers to decoding and decoding the data packets received before. After the correct data packet, the received data packet is symbol-level merged, and the symbol level is combined and decoded.

4. The method according to claim 2 or 3, wherein

Different messages are fed back to the sender according to the packet detection result and the number of receptions:

If the packet is decoded incorrectly, judge

If the number of receptions is 1, the receiving end sends a NAK message to the sending end; If the number of receptions is greater than 1, a precoding matrix is calculated and the precoding matrix index and a NAK message are fed back to the transmitting end.

5. The method according to claim 4, wherein

The data packet detection result and the number of receptions further include if the data packet is decoded incorrectly, the number of receptions is less than a set value, and the receiving end further sends a packet decoding error message to the transmitting end.

6. The method according to claims 1 - 5, wherein

The sending end determines the retransmission mode and the retransmission content according to the feedback message and the number of retransmissions, including:

The method according to claim 6, wherein, further, the data packet transmitted for the first time is used as the data packet transmitted this time, and the data packet that needs to be retransmitted is selected according to the data packet error information and used as the current transmission. data pack.

8. The method according to claim 7, wherein the data packet transmitted this time further includes a new data packet.

9. The method according to claim 6-8, wherein the transmitting end retransmits the data packet by the STBC-based HARQ technology, where the transmitting end sends the common data packet.

10. The method according to claim 6-8, wherein the transmitting end retransmits the data packet by the STBC-based HARQ technology, where the transmitting end sends the orthogonal sequence corresponding to the initial data packet.

11. The method according to claims 4-10, wherein the calculating a precoding matrix is based on a maximum SNR criterion, and calculating an optimized precoding matrix.

12. The method according to claim 11, wherein the received data packet is combined with the data packet received by the next retransmission to perform symbol level combining, and the signal to noise ratio SNR is output after the maximum symbol level is combined. The precoding matrix is calculated.

13. The method according to claim 12, wherein combining the already received data packet with the next retransmission of the received data packet for symbol level merging refers to erasing the already received data packet and respectively decoding the correctly decoded data packet. The next time the next retransmission combines the received packets for symbol level merging.

14. The method according to claim 4 - 13, wherein the set value refers to a maximum number of retransmissions set by the system.

15. An adaptive HARQ retransmission method, the method comprising:

The sender sends a data packet;

16. The retransmission method according to claim 15, wherein

If the number of retransmissions is not greater than a system setting value, the data packet transmitted for the first time is used as the data packet transmitted this time, and the precoding matrix is selected according to the precoding matrix index in the feedback message, and the data packet for the current transmission is selected. Perform precoding and retransmit to the receiving end; if the number of retransmissions is greater than a system setting value, send a new data packet, and set the number of retransmissions to 0;

17. The retransmission method according to claim 16, wherein, further, the first The data packet transmitted once as the data packet transmitted this time refers to the data packet that needs to be retransmitted according to the packet error information in the feedback message and used as the data packet for the current transmission.

18. The retransmission method according to claim 17, wherein the data packet transmitted this time further includes a new data packet.

The retransmission method according to any one of claims 16-18, wherein the transmitting end retransmits the data packet by the STBC-based HARQ technology, that is, the transmitting end sends the data packet to be transmitted.

The retransmission method according to any one of claims 16-18, wherein the transmitting end retransmits the data packet by the STBC-based HARQ technology, that is, the transmitting end sends an orthogonal sequence corresponding to the data packet to be transmitted.

An adaptive HARQ receiving feedback method, the method comprising:

Receiving, by the receiving end, the data packet;

The receiving end determines the number of receptions, and determines the packet detection according to the number of receptions;

Different messages are fed back to the sender according to the packet detection result and the number of receptions.

22. The receiving feedback method according to claim 21, wherein

The receiving end determines the number of times of receiving, and determining the data packet detection according to the number of times of receiving includes: if the number of receiving times is 0, directly decoding the received data packet; otherwise, the data packet received this time and the data packet received in the previous time are at the symbol level. Combined and decoded after the combination.

The receiving feedback method according to claim 22, wherein the combining the data packet received this time and the data packet received in the previous several times after being combined at the symbol level refers to respectively decoding the data packets received in the previous several times. After decoding the correct data packet, it performs symbol level merging with the data packet received this time, and the symbol level is combined and decoded.

The receiving feedback method according to claim 22 or 23, wherein the different messages are fed back to the transmitting end according to the data packet detection result and the number of receptions:

If the packet is decoded incorrectly, judge

If the number of receptions reaches a set value, a NAK message is fed back to the sender. The number of receptions is set to 0;

If the number of receptions is 1, the receiving end sends a NAK message to the transmitting end; if the receiving number is greater than 1, a precoding matrix is calculated and the precoding matrix index and a NAK message are fed back to the transmitting end.

25. The receiving feedback method according to claim 24, wherein

The message that is different according to the packet detection result and the number of receptions is sent to the transmitting end. Further, if the data packet is decoded incorrectly, the number of times of receiving is less than a set value, and the receiving end sends a packet decoding error message to the transmitting end.

The reception feedback method according to any one of claims 24 to 25, wherein said calculating a precoding matrix is based on a maximum SNR criterion, and calculating an optimized precoding matrix.

27. The receiving feedback method according to claim 26, wherein the already received data packet is combined with the data packet to be received by the next retransmission for symbol level combining, and the signal to noise ratio SNR is output after the maximum symbol level combining. The precoding matrix is calculated under the criteria.

The receiving feedback method according to claim 27, wherein combining the already received data packet with the next retransmission to receive the data packet for symbol level merging means that the already received data packet is respectively decoded and decoded correctly. The data packet is combined with the next retransmission to receive the data packet for symbol level merging.

The receiving feedback method according to any one of claims 24 to 28, wherein the set value refers to a maximum number of retransmissions set by the system.

30. An adaptive HARQ retransmission device, the device comprising:

a sending unit, configured to send a data packet;

a receiving unit, configured to receive a feedback message;

a determining unit, configured to determine a feedback message and a number of retransmissions;

The processing unit is configured to determine a retransmission mode and a retransmission content according to the feedback message and the number of retransmissions.

31. The retransmission device according to claim 30, wherein

The determining the retransmission mode and the retransmission content according to the feedback message and the number of retransmissions include: If an ACK message is received, a new data packet is sent, and the number of retransmissions is set to 0;

If a NAK message is received, the number of retransmissions is incremented by one and the number of retransmissions is determined:

If the number of retransmissions is 1, the data packet transmitted for the first time is used as the data packet of the current transmission, and the data packet is retransmitted to the receiving end by the STBC-based HARQ technology, and the retransmitted data packet is sent for the first time. The data packet forms an STBC code word;

If the number of retransmissions is not greater than a system setting value, the data packet transmitted for the first time is used as the data packet transmitted this time, and the precoding matrix is selected according to the precoding matrix index in the feedback message, and the data packet for the current transmission is selected. Perform precoding and retransmit to the receiving end;

If the number of retransmissions is greater than a system setting, send a new packet and set the number of retransmissions to 0;

32. The retransmission apparatus according to claim 31, wherein if the NAK message is received, the data packet transmitted for the first time is used as the data packet transmitted this time, and the selection is required according to the packet error information in the feedback information. The retransmitted data packet is used as the data packet for this transmission.

33. The retransmission device of claim 32, wherein the data packet transmitted this time further comprises a new data packet.

34. The retransmission apparatus according to any one of claims 31 to 33, wherein retransmitting the data packet by the STBC-based HARQ technique means transmitting a common packet of the data packet to be transmitted.

35. The retransmission apparatus according to claim 31-33, wherein retransmitting the data packet by the STBC-based HARQ technology refers to transmitting an orthogonal sequence corresponding to the data packet to be transmitted.

36. An adaptive HARQ receiving feedback device, the device comprising:

a receiving unit, configured to receive the data packet;

a determining unit, configured to determine the number of times of receiving and the decoding of the data packet;

a packet detecting unit, configured to determine a packet detection according to the number of times of receiving;

a feedback unit, configured to perform different cancellation according to the packet detection result and the number of reception times

37. The receiving feedback device according to claim 36, wherein

The determining the packet detection according to the number of receptions includes: if the number of receptions is 0, straight The received data packet is decoded; otherwise, the data packet received this time and the data packet received in the previous time are combined at the symbol level and jointly decoded.

The receiving feedback device according to claim 37, wherein the jointly combining the data packet received this time and the data packet received in the previous several times after being combined at the symbol level means that the data packets received in the previous several times are respectively After decoding the correct data packet, it performs symbol level merging with the data packet received this time, and the symbol level is combined and decoded.

39. The receiving feedback device according to claim 37 or 38, wherein

Different messages based on packet detection results and receiving times feedback include:

If the packet is decoded correctly, an ACK message is fed back, and the number of receptions is set to 0; if the packet is decoded incorrectly, it is judged

If the number of receptions is 1, the receiving end sends a NAK message;

40. The receiving feedback apparatus according to claim 39, wherein the message different in feedback according to the number of receptions further comprises transmitting a packet decoding error message if the data packet is decoded incorrectly, the number of receptions is less than a set value.

41. The receive feedback apparatus according to claims 39-40, wherein said calculating a precoding matrix is based on a maximum SNR criterion to calculate an optimized precoding matrix.

42. The receiving feedback apparatus according to claim 41, wherein the already received data packet is combined with the data packet to be received by the next retransmission for symbol level combining, and the signal to noise ratio S NR is output after maximizing the symbol level combining. The precoding matrix is calculated under the criteria.

43. The receiving feedback apparatus according to claim 42, wherein the symbol level combining of the already received data packet and the next retransmission of the received data packet means that the already received data packet is respectively decoded and decoded correctly. After the data packet is connected with the next retransmission The received packets are combined for symbol level merging.

44. The receiving feedback device according to claims 39-43, wherein the set value refers to a maximum number of retransmissions set by the system.

A network-side device using adaptive HARQ, wherein the network-side device comprises the retransmission device according to any one of claims 30-35.

46. A terminal device employing an adaptive HARQ, wherein the terminal device comprises the retransmission device according to any one of claims 30-35.

A network-side device using adaptive HARQ, wherein the network-side device comprises the receiving feedback device according to any one of claims 36-44.

48. A terminal device employing an adaptive HARQ, wherein the terminal device comprises the receiving feedback device according to any one of claims 36-44.