CN103888231B - Wireless communication system and wireless communications method - Google Patents

Abstract

Wireless communication system and wireless communications method, the wireless communication system include：Sending device has the multiple transmission antennas for the MIMO transmission for executing multiple data blocks；And reception device, it receives the multiple data block, the sending device is transmitted to the reception device into program number by the control channel different from data channel, when executing MIMO diversity transmissions, the reception device not according to for prevent competition between the data block into program number, and according into program number, HARQ processes are executed in the data block received described in being received from the sending device.

Description

Wireless communication system and wireless communication method

This application is based on Article 42 of the Detailed Rules for the Implementation of the Patent Law. It is the application date of October 27, 2006, and the application number is 200680056206.X. Divisional application.

technical field

The present invention relates to a wireless communication system and a wireless communication method in the wireless communication system, in particular to a retransmission control technology suitable for MIMO (Multi Input Multi Output) transmission.

Background technique

With regard to mobile communication systems such as mobile phones, the third-generation system based on CDMA (Code Division Multiple Access) has already begun to serve, and OFDMA (Orthogonal Frequency Division Multiple Access) is being promoted. Research on a next-generation mobile communication system that realizes faster communication based on the method of address access) (refer to Non-Patent Document 1 described later).

Therefore, MIMO has been proposed as a powerful technique for increasing the transmission rate. Fig. 19 shows an overview of a MIMO transmission system. The MIMO transmission system shown in FIG. 19 is configured to include: a transmitting device 100 having a plurality of transmitting antennas (antenna groups) Tx#1, Tx#2, ..., Tx#n (n is an integer greater than or equal to 2); A receiving device 200 for a plurality of receiving antennas (antenna groups) Rx#1, Rx#2, ..., Rx#n. In this MIMO transmission system, different data are transmitted in parallel from each transmitting antenna Tx#i (i=1~n) A spatial multiplexing transmission technique that increases the transmission capacity proportionally to the number n of transmit antennas. Different transmitting antennas Tx#i are configured to have no correlation with each other, and the data streams sent from each transmitting antenna Tx#i respectively pass through independent fading transmission paths, and are mixed with other data streams in space to be received by the receiving antenna Rx# i receive.

As an implementation example of such a MIMO transmission system, as shown in FIG. 20 , for example, there is a method of independently performing stream processing for each antenna. For example, PARC (Per Antenna Rate Control, per-antenna rate control) that does not perform precoding (Precoding) (see Non-Patent Document 2 described later), and PSRC (PerStream Rate Control, per-stream rate control) that performs precoding can be cited. control) (see Non-Patent Document 3 described later) and the like.

Specifically, in the system shown in FIG. 20 , for example, the transmission device 100 is configured to include a stream separation unit 101, a CRC addition unit 102 for each transmission stream, an encoding unit 103, a HARQ processing unit 104, a transmission unit 105, and a retransmission unit 105. The transmission control unit 106 and the receiving device 200 include, for example, a signal separation/combination unit 201 , a HARQ processing unit 202 and a CRC calculation unit 203 for each received stream, an ACK/NACK determination unit 204 , and a stream synthesis unit 205 . In addition, ATR represents the receiving antenna of the transmitting device 100, and ATT represents the transmitting antenna of the receiving device 200. In this example, for convenience, it is shown that an ACK/NACK (Acknowledgment/Negative Acknowledgment) signal (acknowledgment response signal) is transmitted from the transmitting antenna ATT. , and is received by the receiving antenna ATR.

Furthermore, the transmitting device (hereinafter also referred to as the transmitting side) 100 operates, for example, according to the flowchart shown in FIG. 21 , and the receiving device (hereinafter also referred to as the receiving side) 200 operates, for example, according to the flowchart shown in FIG. 22 .

That is, in the transmission device 100, the transmission data is separated into the transmission streams of each antenna group Tx#i by the stream separation unit 101 (step A1), and the error detection is added to the transmission streams of each antenna group Tx#i by the CRC addition unit 102. CRC (CyclicRedundant Check, Cyclic Redundant Check) code (step A2) used, in order to correct the bit error, carry out the coding of the data stream in the coding part 103, in order to retransmit control, carry out the HARQ (Hybrid Automatic RepeatreQuest) processing (step A4), the transmission unit 105 selects and modulates the transmission antenna Tx#i that transmits the HARQ block (process), and transmits it to the reception device 200 . Here, each process can select a plurality of transmit antennas Tx#i when precoding is used ("Yes" in step A5), but when PARC is used ("No" in step A5), it is selected from a predetermined The transmitting antenna Tx#i transmits.

On the other hand, in the receiving apparatus 200, as shown in FIG. Step B1), determine whether the received signal (process) is a retransmission process (step B2). If the result is a retransmission process ("Yes" in step B2), the receiving device 200 uses the HARQ processing unit 202 to combine the signal received this time with the received signal of the same process previously received and held (step B3). Bit errors are detected by checking the CRC attached to each process by the CRC computing unit 203 (step B4). Also, when the process received this time is not a retransmission process ("No" in step B2), the HARQ processing unit 202 does not perform combination, and the CRC calculation unit 203 performs bit error detection (step B4).

And, when a bit error is detected in the ACK/NACK determination section 204 (step B5 is "yes"), the receiving process is maintained and a NACK signal is returned to the transmitting device 100 using the transmitting antenna ATT (step B6), and when no error is detected (step B5: No), an ACK signal is sent back to the transmitting device 100 using the transmitting antenna ATT, and the process is passed to the upper layer (step B7). In addition, the received signals of the streams for which no errors have been detected are finally combined by the stream combining unit 205 and output.

In this series of processing, an important function required for fast communication is HARQ. HARQ is an ARQ scheme that combines automatic repeat request (ARQ) and error correction coding (FEC: Forward Error Correction, forward error correction). Specifically, the transmitting side 100 adds parity bits for error detection to the information bit block to perform error correction coding, and transmits all or part of it. When retransmission occurs, all or part of the coded bits for the current block are retransmitted.

At the receiving side 200, the corresponding bits of each existing block in the retransmission block are combined, and the resultant combined block is used to perform error correction and error detection again. In this way, the receiving side 200 repeats the ACK/NACK reply to the transmitting side 100 and the retry of the decoding process by retransmission until the error of the block is eliminated within the range of the predetermined upper limit number of times.

N-channel Stop-and-Wait ARQ is particularly suitable for next-generation mobile communications (see Non-Patent Document 4 described later). Here, N represents an integer and represents the number of blocks (the number of processes) that can be transmitted simultaneously. Regarding the process of sending at the same time, the retransmission control based on Stop and Wait is performed for each process.

Fig. 23 shows an overview of N-channel Stop-and-Wait ARQ.

Each process is transmitted in a wireless transmission unit interval (TTI: Transmission Time Interval), and is identified by an identifier such as a program number N. In FIG. 23 , the case where the number of processes N=5 (0 to 4) is shown, and therefore corresponds to the case of 5-channel Stop-and-Wait ARQ. In addition, in Fig. 23, for convenience, the data part of each process is added into the program number, but actually the program number is sent through the control channel, and the data part of each process is not added into the program number. That is, the program number is transmitted in the data portion of each process (the same applies hereinafter).

After receiving the process from the sending device 100, the receiving device 200 performs the above-mentioned error detection. Here, it is assumed that among the processes 0 to 4, the processes "1", "3", and "4" have generated errors, and the processes "0" and "2" have not generated errors. For the processes "0", "2" that have not generated errors, ", an ACK signal is returned to the transmission device 100, and for the processes "1", "3", and "4" in which errors occurred, the process is held in a memory (not shown), and a NACK signal is returned to the transmission device 100. The reply of the ACK/NACK signal is also sent through the control channel, but in this case, there is no need to reply to the program number.

The receiving device 200 adjusts the reply timing of each process and replies with an ACK/NACK signal, so that the sending device 100 can identify which process the ACK/NACK signal is for. After the sending device 100 receives the ACK signal, the sending of the new process is carried out, but the process number at this time can be arbitrarily added including the time when the program number is added, and the process number that has not been used in the past 5 processes (in FIG. 23 , the sequence numbers are appended in ascending order of unused sequence numbers).

On the other hand, after receiving NACK, the transmitting device 100 retransmits the process in which an error occurred, and the process number at this time is assigned the same sequence number as the previous process number. After retransmission, the receiving device 200 recognizes the program number and determines which process should be combined with it. That is, when receiving retransmission processes, that is, processes "1", "3", and "4", they are respectively the same as the processes "1", "2", and " 3" for group synthesis. After combining, the CRC is checked, and when it can be received without error, an ACK is returned to the transmitting device 100 . On the other hand, when an error occurs, the combined process is maintained, and a NACK signal is returned to the transmitting device 100 again.

In addition, there are two representative methods regarding the synthesis method, and any of the synthesis methods can be used in the present invention. One is to retransmit exactly the same data as in the previous transmission during retransmission, synthesize the received signal during previous transmission and the received signal during retransmission, and generate the data to be decoded, and the other is to retransmit Change the puncturing pattern of the coded data from time to time, and send the bits that have not been sent so far, combine the received signal of the previous transmission and the received signal of the retransmission, reduce the equivalent coding rate, and improve the error correction capability (coding gain). The latter technology is called IR (Incremental Redundancy, incremental redundancy).

This processing is carried out in the same manner regardless of the similarities and differences between PARC and precoding described above. Therefore, PARC is taken as an example to continue the description below.

FIG. 24 shows the state of N-channel Stop-and-WaitARQ when the transmitting apparatus 100 and the receiving apparatus 200 support PARC.

As mentioned above, in PARC, CRC addition, encoding, and HARQ processing are performed independently for each antenna, so the HARQ process number is also appended with an independent sequence number. FIG. 24 shows a case where retransmission occurs in the processes "1", "3", and "4" transmitted from the transmission antenna Tx#1 and the process "1" transmitted from the transmission antenna Tx#2 (see the dotted arrow). In this case, as described above, HARQ is performed for each antenna group, so retransmission control is independently performed for each antenna group. In addition, the procedure number is added according to the same rules as in FIG. 23 .

Furthermore, in MIMO transmission of the next generation mobile communication system, the transmitting device 100 transmits antenna identification signals (for example, pilot signals and scrambling codes) in order to separate/combine data signals transmitted between transmitting antennas Tx#i.

FIG. 25 shows an example of adding pilot signals when the transmitting device 100 has two transmitting antennas. As shown in (1) and (2) in FIG. 25 , pilot signals (R: Reference Symbol) are added in the same time sequence and different frequency sequences between the antenna groups Tx#1 and Tx#2. The receiving apparatus 200 separates the signal of the antenna group Tx#1 from the signal received by the antenna group Rx#1 of the receiving apparatus 200, and separates the signal of the antenna group Tx#1 from the signal received by the antenna group Rx#2 of the receiving apparatus 200 by referring to the pilot signal. The signal of group Tx#2 restores the stream (process) transmitted after combining each signal. And usually, the correspondence relationship between the antenna group and the pilot signal is transmitted using notification information.

Non-Patent Document 1: "3GPP TR25.913V7.3.0 Requirements for Evolved UTRA (E-UTRA) and Evolved UTRAN (E-UTRAN) (Release 7)," 3GPP (France), 2006-03

Non-Patent Document 2: Lucent, "Improving MIMO throughput with per-antenna ratecontrol (PARC)," 3GPP (France), 2001-08

Non-Patent Document 3: Lucent, "Per Stream Rate Control with Code Reuse TxAA and APP Decoding for HSDPA," 3GPP (France), 2002-09

Non-Patent Document 4: "3GPP TR25.814V7.4.0 Physical Layer Aspects for evolved Universal Terrestrial Radio Access (UTRA) (Release 7)," 3GPP (France), 2006-06

Regarding the communication environment to which the MIMO transmission system is applied, for example, the cell structure shown in FIG. 26 can be cited. That is, a cell is divided into areas according to the form of MIMO transmission. As shown in FIG. (transmission using two streams in FIG. 26(1)), and in the outer area (non-MIMO multiplexing transmission area) 303, non-MIMO multiplexing transmission (transmission using one stream in FIG. 26(1)). In addition, "non-MIMO multiplexing transmission" refers to, for example, MIMO diversity transmission and MIMO single transmission in which one antenna is used to transmit and receive one stream.

Furthermore, as shown in FIG. 26(2), even in the MIMO multiplexing transmission area 302, when the mobile station 400 is located in the vicinity area 301 of the base station 300 and performs line-of-sight communication, non-MIMO multiplexing may be performed. The case of using transmission (using one stream transmission in Fig. 26(2)). This is because antenna-to-antenna correlation occurs during line-of-sight communication, so it is difficult to separate/combine signals in the receiving device 200, and there is a possibility that a high traffic volume cannot be realized.

In this case, MIMO multiplexing transmission is not performed even in the vicinity area 301 of the base station 300, but non-MIMO multiplexing transmission is performed with a high modulation rate and a high coding rate. This method may realize high traffic volume.

In this way, MIMO multiplexing transmission is not fixedly applied in one cell, but non-MIMO multiplexing transmission is sometimes applied depending on the location of mobile station 400 . For example, when the radio quality of the mobile station 400 (for example, the average value of the SN ratio reported by the mobile station 400 to the base station 300) is greater than a certain threshold, MIMO multiplexing transmission is performed, and when it is less than the threshold, non-MIMO multiplexing transmission is performed.

At this time, the number of streams is reduced from multiple streams to one stream. For example, in the method of independently attaching program numbers to each antenna group like PARC, when the number of streams decreases, the program numbers of HARQ are repeated (competition), which may cause Cannot continue communication.

For example, FIG. 27 shows an example of operation when switching from MIMO multiplexing transmission to MIMO diversity transmission in PARC. This example shows a case where an ACK/NACK signal is replied with one stream.

The antenna group Tx#1 and the antenna group Tx#2 of the slave sending device 100 follow the timing transmission process "0", "1" and "2" shown in FIG. After the ACK signals of the processes "0" and "1" transmitted by the respective antenna groups Tx#1 and Tx#2, at the timing indicated by symbol 500 in FIG. Use the transmission area 302 to move to the non-MIMO multiplexing transmission area (MIMO diversity transmission area) 301 or 303 .

At this time, if the main antenna group of the transmitting device 100 that processes the incoming stream is set as the antenna group Tx#2, the transmitting device 100 transmits from the antenna groups Tx#1 and Tx#2 before switching to MIMO diversity transmission. Stored process "2". The receiving apparatus 200 receives these signals using the antenna group Rx#1 and Rx#2, and combines the signals to construct a process "2". Then, the receiving apparatus 200 attempts to perform packet combination with the process "2" held at the time of the previous transmission, but the following problems arise here.

(Problem 1) The receiving apparatus 200 cannot recognize with which process the retransmission process "2" should be synthesized. That is, for example, as shown in FIG. 28 , the receiving apparatus 200 receives the retransmission process "2" through MIMO diversity. Since the group Rx#2 holds the process "2", it cannot be determined which process it will merge with. Assume that in the case of trying to combine with the process (refer to symbol 601) held by the main antenna group Rx#2, the process "2" (refer to symbol 602) of the antenna group Rx#1 and the antenna group Rx# represented by symbol 601 are combined. The process "2" of 2 performs group synthesis, which destroys the integrity of the synthesis.

In addition, the following problems also arise.

(Problem 2) In the transmitting apparatus 100, erroneous retransmissions as shown in the following cases 1 and 2 occur.

(Case 1) When the ACK/NACK signal is returned by timing adjustment

In this case, the base station instructs the mobile station to reply timing (reply time and reply frequency) of ACK/NACK.

Fig. 29 shows its outline. The receiving device 200 responds with an ACK/NACK signal by adjusting the timing of the main antenna group Rx#2. At this time, the sending device 100 uses the timing information of the main antenna group Tx#2 to receive the reply. In this case, as shown in FIG. 29 , the timing at which the transmitting device 100 receives the reply coincides with the retransmission timing of the process "2" of the antenna group Tx#2 indicated by symbol 603, and the retransmission of the process "2" of the antenna group Tx#1 should have been retransmitted. Process "2", but it is possible to retransmit process "2" of antenna group Tx#2 by mistake. At this time, the process "2" of the antenna group Tx#1 cannot be retransmitted.

(Case 2) The case where the ACK/NACK signal is replied by using the sequence number instead of the time timing adjustment

This case refers to a case where ACK/NACK reply is executed without timing adjustment. Therefore, different from case 1, there is no need to perform an instruction of response timing adjustment, but a program number needs to be added when replying ACK/NACK.

Fig. 30 shows its outline. The receiving device 200 indicates the program number from the main antenna group Rx#2 and replies with an ACK/NACK signal. At this time, the reply is received through the antenna group Tx#2. At this time, as shown in FIG. 30 , when receiving the reply for the process “2” of the antenna group Tx#1, the transmitting apparatus 100 misinterprets it as a NACK signal for the process “2” of the antenna group Tx#2. Therefore, the process "2" of the antenna group Tx#1 cannot be retransmitted.

In this way, when the program numbers are repeated in each antenna group, the following problems will occur. In the receiving device 200, it cannot be determined which antenna group processes are to be combined. On the other hand, a process error occurs in the transmitting device 100. Resend, so that the process that should have been resent cannot be resent.

Furthermore, when an acknowledgment (ACK/NACK signal) is returned from the receiving device 200 to the transmitting device 100 using two streams, the same problem as the above-mentioned problem occurs. Figures 31 and 32 show this situation. That is, in receiving apparatus 200 , as shown in FIG. 28 , it cannot be determined which process the retransmission process "2" should be combined with, respectively held by antenna group Rx#1 and antenna group Rx#2. Also, the same problems as those described above using FIGS. 29 and 30 occur in the transmitting device 100 .

That is, when switching from MIMO multiplexing transmission to MIMO diversity transmission,

(1) When the acknowledgment response returned from the receiving device 200 is returned from the antenna group Rx#2, as shown in FIG. 31 , an ACK/NACK signal is returned from the transmitting antenna ATT2 of the receiving device 200. The action of the device 100 is the same as that shown in FIG. 29 and FIG. 30 , so the process "2" of the antenna group Tx#2 is wrongly retransmitted, and the process "2" of the antenna group Tx#1 cannot be retransmitted.

(2) When the acknowledgment reply from the receiving device 200 is replied by MIMO diversity, as shown in FIG. The signals replied by ATR2, but since the main antenna group is the antenna group Tx#2, they are finally determined to be the reply for the antenna group Tx#2. Therefore, the course "2" of the antenna group Tx#2 is erroneously retransmitted, and the course "2" of the antenna group Tx#1 cannot be retransmitted.

Contents of the invention

The present invention was made in view of the above-mentioned problems, and its object is to maintain the sequence number (i.e. identification) and can continue to communicate normally.

In order to achieve the above objects, the present invention is characterized by using the following transmission control method, transmitting apparatus, and receiving apparatus in a wireless communication system. which is,

(1) The first aspect of the transmission control method in the wireless communication system of the present invention is characterized in that, in wireless communication, a plurality of stream data can be transmitted from a transmitting device having a plurality of transmitting antennas to a receiving device in predetermined data block units. In the system, the sending device appends data block identification information without contention between the stream data to each of the plurality of stream data, and sends the data block to the receiving device, and the receiving device according to the The data block identification information attached to the received data block of the sending device performs retransmission combination processing on the received data block and the retransmitted data block to which the same data block identification information is added.

(2) Here, the transmitting device may also add information including an antenna identifier, which is related to the transmitting antenna that transmits the streaming data, to the data block as the data block identification information identifier.

(3) In addition, the sending device may also group a series of serial number information according to each stream data, and attach the serial number information in the corresponding group as the data block identification information to the serial number information according to each stream data. in the data block described above.

(4) In addition, the receiving device may also add the data block identification information to the retransmission request for the received data block, and send the retransmission request to the sending device. When requesting, the data block identified by the data block identification information attached to the retransmission request is retransmitted to the receiving device as the retransmission data block.

(5) Furthermore, the second aspect of the transmission control method in the wireless communication system of the present invention is characterized in that, in a wireless communication system capable of transmitting a plurality of stream data from a transmitting device having a plurality of transmitting antennas to a receiving device, the The transmission device detects the reduction control factor of the stream data amount, and when the decrease control factor is detected, delays the reduction control timing of the stream data amount according to the untransmitted data amount of the stream data subject to reduction control.

(6) Here, the transmission device may perform the reduction control after the transmission of the untransmitted data is completed.

(7) Furthermore, the transmission device may monitor the radio quality with the reception device, and execute the reduction control even if the transmission of the remaining data is not completed when the radio quality is lower than a predetermined threshold.

(8) In addition, the transmitting device may monitor the wireless quality with the receiving device, and if there is no remaining data of stream data to be reduced at the time point when the wireless quality is lower than a predetermined threshold value, the A reduction control of the number of streams is implemented.

(9) Furthermore, the transmitting device of the present invention is a transmitting device in a wireless communication system capable of transmitting a plurality of stream data in predetermined data block units from a transmitting device having a plurality of transmitting antennas to a receiving device, and the transmitting device is characterized in that , having: a data block identification information adding unit, which adds data block identification information to the data block according to each of the plurality of stream data; a sending unit, which sends the data to the receiving device a data block of block identification information; and a control unit that controls the data block identification information adding unit so that the data block identification information appended to the data block does not compete among the respective stream data.

(10) Here, the control unit may be configured to include an antenna identifier generating unit that uses information including the antenna identifier of the transmitting antenna for the data stream as information to be added to the data stream. The data block identification information in the data block is provided to the data block identification information adding unit.

(11) In addition, the control unit may also be configured to have a group-by-group serial number generation unit, which groups a series of serial number information according to each data stream, and groups the corresponding serial number information according to each data stream. The sequence number information in the group is provided to the data block identification information adding means as data block identification information to be added to the data block.

(12) In addition, the sending device may further have a retransmission control unit, and when receiving a retransmission request for the received data block to which the data block identification information is appended from the receiving device, the retransmission The transmission control unit retransmits the data block identified by the data block identification information to the receiving device.

(13) Furthermore, the receiving device of the present invention is a receiving device in a wireless communication system capable of transmitting a plurality of stream data in predetermined data block units from a transmitting device having a plurality of transmitting antennas to a receiving device, wherein the receiving device The device has: a receiving unit that receives a data block transmitted by the transmitting device according to each of the plurality of stream data after adding data block identification information that does not compete among the stream data; and repeating The sending and combining unit performs retransmission and combining processing on the received data block and the retransmitted data block to which the same data block identification information is added according to the data block identification information attached to the received data block received by the receiving unit.

(14) In addition, the receiving device may further include a retransmission request sending unit that adds the data block identification information to the retransmission request for the received data block, and sends the retransmission request to to the sending device.

Invention effect

According to the present invention described above, at least the following effects or advantages can be obtained.

That is, when the number of transport streams between the transmitting device and the receiving device changes (decreases) even as in the case where the transmission mode is switched from MIMO multiplexing transmission to non-MIMO multiplexing transmission (MIMO diversity transmission, etc.), There is also no contention of data block recognition among the data blocks, so that the erroneous retransmission of the data block sending device and the erroneous combination in the receiving device can be avoided. Therefore, normal communication (streaming) between the transmitting device and the receiving device can be continued.

Description of drawings

FIG. 1 is a block diagram showing the configuration of a MIMO transmission system according to the first embodiment of the present invention.

FIG. 2 is a block diagram collectively showing an example of a sequence number for explaining a method of adding sequence numbers in the MIMO transmission system shown in FIG. 1 .

FIG. 3 is a diagram for explaining retransmission processing operations in the MIMO transmission system shown in FIG. 1 .

FIG. 4 is a flowchart for explaining the operation of the transmission device in the MIMO transmission system shown in FIG. 1 .

FIG. 5 is a diagram for explaining an ACK/NACK reply method (case 1) in the MIMO transmission system shown in FIG. 1 .

FIG. 6 is a flowchart for explaining the operation (case 1) of the receiving device in the MIMO transmission system shown in FIG. 1 .

FIG. 7 is a diagram for explaining an ACK/NACK reply method (case 2) in the MIMO transmission system shown in FIG. 1 .

Fig. 8 is a flowchart for explaining the operation (case 2) of the receiving device in the MIMO transmission system shown in Fig. 1 .

FIG. 9 is a block diagram showing an example of a configuration and sequence number of a MIMO transmission system according to the second embodiment of the present invention.

FIG. 10 is a block diagram together showing an example of sequence numbers for explaining another method of adding sequence numbers in the MIMO transmission system shown in FIG. 9 .

FIG. 11 is a diagram for explaining retransmission processing operations in the MIMO transmission system shown in FIG. 9 .

FIG. 12 is a flowchart for explaining the operation of the transmitting device in the MIMO transmission system shown in FIG. 9 .

Fig. 13 is a flowchart for explaining the operation (case 1) of the receiving device in the MIMO transmission system shown in Fig. 9 .

Fig. 14 is a flowchart for explaining the operation (case 2) of the receiving device in the MIMO transmission system shown in Fig. 9 .

FIG. 15 is a diagram for explaining retransmission processing operations in the MIMO transmission system according to the third embodiment of the present invention.

FIG. 16 is a diagram illustrating a MIMO transmission switching method according to the third embodiment.

FIG. 17 is a diagram for explaining a MIMO transmission switching method according to the fourth embodiment of the present invention.

FIG. 18 is a diagram for explaining retransmission processing operations in the MIMO transmission system according to the fourth embodiment.

Fig. 19 is a schematic diagram of a MIMO transmission system.

FIG. 20 is a block diagram showing a configuration example of a transmitting device and a receiving device in the MIMO transmission system shown in FIG. 19 .

FIG. 21 is a flowchart for explaining the operation of the transmission device in the MIMO transmission system shown in FIG. 20 .

FIG. 22 is a flowchart for explaining the operation of the receiving device in the MIMO transmission system shown in FIG. 20 .

FIG. 23 is a diagram for explaining the outline of N-channel Stop-and-Wait ARQ in the MIMO transmission system shown in FIG. 20 .

FIG. 24 is a diagram showing a state of N-channel Stop-and-Wait ARQ when the transmitting device and receiving device in the MIMO transmission system shown in FIG. 20 correspond to PARC.

Fig. 25 is a diagram showing an example of pilot signal addition in the MIMO transmission system shown in Fig. 20 .

Fig. 26 is a block diagram showing an example of a cell structure of a MIMO transmission system.

FIG. 27 is a diagram for explaining an example of operation when switching from MIMO multiplexing transmission to MIMO diversity transmission in PARC.

FIG. 28 is a diagram for explaining problems of the conventional technique.

FIG. 29 is a diagram for explaining problems of the conventional technique.

FIG. 30 is a diagram for explaining problems of the conventional technique.

FIG. 31 is a diagram for explaining problems of the conventional technique.

FIG. 32 is a diagram for explaining problems of the conventional art.

Label description

1. Transmitting device (base station); 11. Stream separating unit; 12. CRC adding unit; 13. Coding unit; 14. HARQ sending processing unit (data block identification information adding unit); 15. Sending unit; Additional part (control unit: antenna identifier generation part, group sequence number generation part); 2 receiving device (mobile station); 21 signal separation/combining part (receiving unit); 22 HARQ receiving processing part (retransmission combining unit); 23 CRC operation part; 24 ACK/NACK judgment part (retransmission request sending unit); 25 stream synthesis part; ); Rx#1, Rx#2, ..., Rx#n receiving antenna (antenna group); ATT transmitting antenna; ATR receiving antenna.

Detailed ways

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments, and it is needless to say that various modifications can be made and implemented without departing from the gist of the present invention.

(A) Explanation of the first embodiment

FIG. 1 is a block diagram showing a configuration of a MIMO transmission system according to a first embodiment of the present invention. The MIMO transmission system shown in FIG. 1 is configured to include a plurality of transmission antennas (antenna groups) Tx#1 and Tx#2. , . . . , at least one transmitting device 1 of Tx#n; and at least one receiving device 2 having a plurality of receiving antennas (antenna groups) Rx#1, Rx#2, . . . , Rx#n. Also, the transmitting device 1 can be used as a transmitting system of a base station device, and the receiving device 2 can be used as a receiving system of a mobile station device, for example. Also, in this example, the number of transmitting antennas and the number of receiving antennas are set to be the same number (n), but they may be different.

In addition, the transmission device 1 is configured to include, for example, a stream separation unit 11, a CRC addition unit 12 for each transmission stream, an encoding unit 13, a HARQ transmission processing unit 14, a transmission unit 15, and a retransmission control unit while focusing on its main parts. 16 and the program number addition unit 17, when the receiving device 2 focuses on its main parts, for example, it is configured to include a signal separation/combination unit 21, a HARQ reception processing unit 22 and a CRC calculation unit 23 for each received stream, and an ACK/NACK determination Part 24, stream compositing part 25 and program number assigning part 26. In addition, in this FIG. 1, ATR represents the receiving antenna of the transmitting device 1, and ATT represents the transmitting antenna of the receiving device 2. For convenience of description, an acknowledgment (ACK/NACK signal) is transmitted from the transmitting antenna ATT of the receiving device 2 using one stream. ), and the acknowledgment response (ACK/NACK signal) is received by the receiving antenna ATR of the transmitting device 1 as a premise.

Here, in the transmission device 1, the stream separation unit 11 separates the transmission data signal into transmission streams for each antenna group Tx#i, the CRC adding unit 12 adds a CRC code for error detection to each of the transmission streams, and the encoding unit 13 Each of the transmission streams to which the CRC code is added is encoded into a necessary error correction code such as a Turbo code.

The HARQ transmission processing unit 14 performs HARQ processing (blocking) on the transmission stream according to each program number and sends it to the transmission unit 15, and temporarily stores the HARQ block (process) in a memory not shown for retransmission For control, the transmission unit 15 performs modulation, DA conversion, and frequency conversion to a radio frequency (RF) signal ( Up-frequency conversion) and other necessary wireless transmission processing, and transmit to the receiving device 2 from any one of the transmitting antennas Tx#i.

The retransmission control section 16 performs the following control: According to the ACK/NACK signal from the receiving device 2 received by the receiving antenna ATR, it is determined whether retransmission is required, and if retransmission is required, the antenna group Tx#i and the process to be retransmitted are determined. , read out the stored corresponding process from the memory of the HARQ transmission processing unit 14 corresponding to the retransmission target antenna group Tx#i, and send it to the transmission unit 15 . In addition, the antenna group Tx#i and the process to be retransmitted can be determined, for example, by adjusting the timing of the ACK/NACK signal described above or specifying the process number for the ACK/NACK signal, as will be described later.

And, the program number adding unit 17 adds a program number to each HARQ block (data block) in each HARQ transmission processing unit 14, and in this example, information having the format of (antenna identifier)+(serial number) is used as The program number is given to the HARQ transmission processing unit 14, and the information that there is no contention (duplication) among the antenna groups Tx#i (between the transmission streams), that is, the transmission stream identifier is added to the transmission stream. For example, as shown schematically in Figure 2, the program number attached to the transmission stream of antenna group Tx#1 can be expressed as "0...00xxx" using a bit string, and the program number attached to the transmission stream of antenna group Tx#2 The program number in the stream is expressed as "0...01yyy", and the program number attached to the transmission stream of the antenna group Tx#n is expressed as "1...11zzz" (where x, y, z are 0 or 1). The transmitting device 1 transmits the transmission stream to the receiving device 2 after adding such an independent process number.

That is, the HARQ transmission processing unit 14 functions as a data block identification information adding unit, and adds a program number (data block identification information) to a process (data block) for each of a plurality of streams, and the program number adding unit 17 functions as a control unit that controls the HARQ transmission processing unit 14 so that the process number added to the process does not compete among the streams, and the process number adding unit 17 also functions as an antenna identifier generating unit The role of this is to provide the HARQ transmission processing unit 14 with information including the antenna identifier of the transmit antenna Tx#i of the stream as a sequence number added to the process of the stream.

On the other hand, in the receiving device 2, the signal separation/combination unit 21, under the control from the process allocation unit 26, transmits from each transmission antenna Tx#i (i = 1 to n) and spatially multiplexes each The signal received by the receiving antenna Rx#i is separated according to each process, and diversity synthesis processing can be performed during MIMO diversity. The HARQ reception processing unit 22 performs the reception flow (process) obtained by the signal separation/combination unit 21 together with the process number. It is stored for retransmission synthesis processing, and the stored process is combined with the retransmission process of the same program number from the sending device 1.

That is, the above-mentioned signal separation/combination unit 21 functions as a receiving unit that receives the streams transmitted by the transmission device 1 after adding a process number (sequence number information including an antenna identifier) that does not compete between streams for each stream. process, the HARQ reception processing unit 22 plays the role of a retransmission combining unit, which performs a process number on a received process to which the same process has been added and The retransmission process performs retransmission composition processing.

The CRC calculation unit 23 performs CRC calculation on the received streams obtained by the HARQ reception processing unit 22 to perform an error check, and the ACK/NACK determination unit 24 generates an acknowledgment response signal based on the CRC calculation result, and transmits (feedback) from the transmission antenna ATT To the transmitting device 1, specifically, when the CRC operation result indicates normal (OK), an ACK signal is generated and fed back to the transmitting device 1, and when the CRC operation result is abnormal (NG), a NACK signal is generated and fed back to the transmitting device 1 .

Here, the ACK/NACK determination unit 24 of this example can add a part (antenna identifier) or all (sequence number) of the sequence number information to an acknowledgment response signal (ACK/NACK signal), and transmit it to sending device 1. That is, the ACK/NACK determination unit 24 of this example functions as a retransmission request transmitter, which adds an antenna identifier or a procedure number to a retransmission request (NACK signal) for a reception process, and transmits it to the transmission device 1 .

The stream combining unit 25 combines the streams whose CRC calculation results by the respective CRC calculating units 23 are OK, and outputs the streams as received data.

And, the process allocation part 26 identifies the process number of the receiving process, and controls the signal separation and synthesis processing in the signal separation/combining part 21 according to the process number, so that the receiving process is allocated and input to any of the HARQ reception processing parts 22. party. In addition, in order to identify the process number, in the process allocating unit 26, the process number used in the process number adding unit 17 and information related to the method of adding it are stored in advance in a memory (not shown) or the like, and the transmission device 1 and The receiving apparatus 2 shares the addition method of the program number.

Hereinafter, the operation of the MIMO transmission system according to the present embodiment configured as described above will be described with reference to FIGS. 3 to 8 .

First, in the transmission device 1, the transmission data is separated into the transmission streams of each antenna group Tx#i by the stream separation unit 11, and the CRC code is added by the corresponding CRC addition unit 12, and then encoded by the encoding unit 13. into necessary error correction codes such as Turbo codes, and input to the HARQ transmission processing unit 14.

In the HARQ transmission processing unit 14, HARQ processing (blocking) is performed on the transmission stream input from the encoding unit 13, and as shown in FIG. 2, the program number is added under the control of the program number adding unit 17, and the HARQ block is stored (Process) for retransmission control and sent to the sending unit 15.

Thus, the transmission unit 15 performs the above-described wireless transmission processing on the process input from each HARQ transmission processing unit 14, and transmits to the reception device 2 from any one of the transmission antennas Tx#i. FIG. 3 schematically shows this situation. 3 shows the case where the antenna groups for transmission and reception are n=2, and it shows that the "antenna identifiers" of the antenna groups Tx#1 and Tx#2 are respectively set to "0" and "1", and the HARQ block The "serial number" is set to 0, 1, 2, ..., and the process numbers "0-0", "0-1", "0-2", ... are sequentially added to the processes sent from the antenna group Tx#1. The process sent from the antenna group Tx#2 is sequentially appended with "1-0", "1-1", "1-2", ... and sent to the receiving device 2 (refer to FIG. 3 toward the bottom of the paper) in the case of the solid arrow).

In addition, when the transmission device 1 reduces the number of antenna groups to be used (refer to symbol 500 in FIG. 3 ) as in the case of switching from MIMO multiplexing transmission to MIMO diversity transmission (hereinafter sometimes referred to as transmission mode switching), the above-described Similarly, the above method of adding program numbers by the program number adding unit 17 is also maintained, and stream transmission is performed. Here, when the transmission of streams other than the main antenna group Tx#i is completed, the antenna identifier may be omitted, and transmission and reception may be performed in progress. Here, the so-called "main antenna group" refers to the antenna group maintained in use before and after the switching of the transmission mode (hereinafter the same), and refers to the antenna group Tx#2 in the example of FIG. 3 .

FIG. 4 shows an operation flowchart of the transmitting device 1 including such an option. That is, the transmission device 1 performs stream transmission by adding a program number as described above by the program number adding unit 17 (step S11), and monitors and determines whether a transmission mode switching (change to MIMO diversity transmission) occurs by using the retransmission control unit 16. (Step S12), if the transmission mode switching does not occur (step S12 is "No"), the retransmission control unit 16 controls the program number addition unit 17 and the HARQ transmission processing unit 14 to continue the stream transmission with the program number added.

On the other hand, if the transmission mode switching occurs (YES in step S12), the retransmission control unit 16 determines whether there is no data (process) to be transmitted other than the main antenna group Tx#i (step S13). Exist (step S13 is "No"), then be identical with above-mentioned step S11, control program number adding part 17 and HARQ transmission processing part 14, so that add program number by entering program number adding part 17, and carry out stream transmission (step S14).

On the other hand, if there is no data (process) to be transmitted other than the main antenna group Tx#i (YES in step S13), the retransmission control unit 16 controls the program number addition unit 17 and the HARQ transmission processing unit 14, In order to add the program number of the antenna identifier, which is an element in which the program number is omitted, stream transmission is performed (step S15).

On the other hand, in the receiving apparatus 2, the signals received by the respective receiving antennas Rx#i are separated for each process by the signal separation/combination unit 21 according to the control from the process allocation unit 26, and distributed to each HARQ reception processing unit Either of 22.

In the HARQ reception processing section 22, the reception process from the signal separation/combination section 21 is stored together with the program number for retransmission and synthesis processing, and the stored process is the same as that retransmitted from the transmission device 1. The retransmission process synthesis of the program number (in the case of no retransmission process, directly output the receiving process).

Then, in the corresponding CRC calculation unit 23, a CRC calculation is performed on the reception process output from the HARQ reception processing unit 22, and an acknowledgment signal (ACK signal or NACK signal) corresponding to the calculation result is generated by the ACK/NACK determination unit 24, This signal is fed back to the transmitting device 1 via the transmitting antenna ATT (refer to the arrow pointing upward in FIG. 3 ). However, the ACK/NACK determination unit 24 includes the antenna identifier or the sequence number in the acknowledgment signal.

In addition, the process whose CRC calculation result is normal is combined with other processes receiving streams in the stream synthesis unit 25, and output as normally received data, and the process with an abnormal CRC calculation result is not input to the stream synthesis unit. 25 and discarded it.

In addition, in the transmission device 1, the program number addition unit 17 and the HARQ transmission processing unit 14 are controlled so that if an ACK signal is received from the reception device 2 as an acknowledgment signal, a new process is transmitted, and if a NACK signal is received, a retransmission is performed on the receiving end. Device 2 is an abnormal process. In addition, a new process/a process that should be retransmitted is determined based on the antenna identifier or process number included in the received acknowledgment signal.

Thus, the HARQ transmission processing unit 14 also retransmits the process with the same process number as the process number at the time of the previous transmission when retransmitting the process, and the receiving device 2 realizes the identification of the received process number and the allocation control of the receiving process by the process allocating unit 26. When switching from MIMO multiplexing transmission to non-MIMO multiplexing transmission such as MIMO diversity transmission or MIMO single transmission, even if the number of transmission streams (the number of transmission antennas) fluctuates, the HARQ reception processing unit 22 can perform correct processing Synthesis.

For example, consider the case where a switch to MIMO diversity transmission occurs at the timing indicated by symbol 500 in FIG. Whichever retransmission process of the program number the sending device 2 receives (refer to the double arrow toward the bottom of the paper in FIG. Synthesis between processes with the same sequence number. That is, it is possible to prevent the integrity of the synthesis from being broken (the aforementioned problem 1 can be solved).

In addition, according to the following cases 1 and 2, the reply method of ACK/NACK is studied, and thus the aforementioned problem 2 can also be solved, that is, the wrong retransmission of the process occurs in the sending device 1, so that the retransmission that should have been retransmitted cannot be retransmitted. process problem.

(Case 1) When ACK/NACK signals are received by timing adjustment (Fig. 5, Fig. 6)

FIG. 5 shows a schematic diagram corresponding to FIG. 3 in this case 1. As shown in FIG. As shown in FIG. 5 , even after transmission mode switching (change to MIMO diversity transmission) occurs (refer to reference numeral 500), the receiving device 2 sends an acknowledgment signal using (adding) the antenna identifier of each antenna group ( ACK/NACK signal) reply. Here, "using" the antenna identifier does not indicate that an ACK/NACK signal is returned by adding an antenna identifier, but that, for example, even when the main antenna group is specified as one, the transmitting apparatus indicates each antenna to the receiving apparatus. The frequency band of the ACK/NACK signal of the group is used by the receiving device to reply the ACK/NACK. Therefore, when the transmitting device receives the ACK/NACK signal, it analyzes its frequency band to identify which antenna group the ACK/NACK is for. On the other hand, the meaning of "addition" of an antenna identifier refers to explicitly adding an antenna identifier to an ACK/NACK signal, as shown in FIG. 5 .

For example, in FIG. 5, if attention is paid to the process "0-2" transmitted from the antenna group Tx#1 (the main antenna group is Tx#2) of the transmitting device 1 after the transmission mode switching occurs, the receiving device 2 utilizes ACK/NACK The determination unit 24 generates a signal to which the antenna identifier “0” which is the serial number element (part) of the receiving process “0-2” is added as a response acknowledgment signal for the process “0-2”, and returns it to the transmitting device 1 .

Thus, the transmitting device 1 acquires synchronization with the receiving device 2 at least with respect to the reply timing of the acknowledgment signal for the transmission progress (that is, the transmitting device 1 receives the acknowledgment signal through timing adjustment with the receiving device 2) as The premise is that the retransmission control unit 16 can be used to identify that the acknowledgment signal is for the process "0-2", so that the process "1-2" will not be retransmitted by mistake, and the main antenna group Tx#2 can correctly Resend process "0-2".

In addition, when the transmitting device 1 performs transmission and reception of the process by omitting the antenna identifier as described above (that is, in the case of being able to transmit all the processes except the main antenna group Tx#2), the reply of the confirmation response, even if Since the acknowledgment signal is transmitted without the antenna identifier and the timing is adjusted, the transmission device 1 can recognize which process the acknowledgment signal is for.

FIG. 6 shows an operation flowchart of the receiving device 2 in this case 1. As shown in FIG.

That is, the receiving device 2 monitors and determines whether a transmission mode switching (change to MIMO diversity transmission) occurs (step S21), and if the transmission mode switching does not occur (step S21: No), the ACK/NACK determination unit 24 An acknowledgment signal to which the antenna identifier, which is the serial number element of the receiving process, is added is generated and returned to the transmitting device 1 . When the acknowledgment signal is a NACK signal, the HARQ reception processing unit 22 maintains the reception process for retransmission synthesis (step S22).

On the other hand, when the transmission mode switching occurs (YES in step S21), the receiving device 2 uses the process allocation unit 26 to separate the receiving process (identify the program number) (step S23), and determines whether an antenna identification is added. character (step S24). As a result, if the antenna identifier is added ("Yes" in step S24), then the receiving device 2 generates an acknowledgment signal to which the antenna identifier, which is the serial number element of the receiving process, is added in the same manner as in the above-mentioned step S22, and replies to the sending device. The device 1, and when the acknowledgment signal is a NACK signal, the HARQ reception processing unit 22 maintains the reception process for retransmission and synthesis (step S25).

On the other hand, when the antenna identifier is not added (step S24 is "No"), the receiving device 2 has adjusted the timing, so the reply of the confirmation response omits the antenna identifier, and replies to the transmitting device 1, and in the confirmation When the response signal is a NACK signal, the HARQ reception processing unit 22 maintains the reception process for retransmission synthesis (step S26).

In this way, in this case 1, whenever a transmission mode switching (change to MIMO diversity transmission) occurs and each transmission process needs to be identified among each antenna group Tx#i (Rx#i), only the acknowledgment response signal is added. Receive the information elements of the program number, that is, the antenna identifier, suppress its information volume to the minimum and reply to the sending device 1 at the same time, and can transmit all processes except the main antenna group Tx#2. If each antenna group Tx#i(Rx# i) If there is no need to identify each transmission process, the addition of the antenna identifier is omitted, so the effective use of radio resources between the transmission device 1 and the reception device 2 can be realized.

(Case 2) The case where the ACK/NACK signal is returned by explicitly adding a program number (Fig. 7, Fig. 8)

FIG. 7 shows a schematic diagram corresponding to FIG. 3 and FIG. 5 in this case. As shown in FIG. 7, even after transmission mode switching (change to MIMO diversity transmission) occurs (refer to reference numeral 500), since timing adjustment is not performed between the transmitting device and the receiving device, the receiving device 2 explicitly adds Enter the program number to reply ACK/NACK.

For example, in this case 2, in FIG. 7, if attention is paid to the process "0-2" transmitted from the antenna group Tx#1 (the main antenna group is Tx#2) of the transmission device 1 after the transmission mode switching occurs, Then, the receiving device 2 uses the ACK/NACK determination unit 24 to generate a signal with the process number of the receiving process "0-2" added as an acknowledgment signal for the process "0-2", and replies to the transmitting device 1 .

Thus, the retransmission control unit 16 can identify to which antenna group the acknowledgment signal is directed, regardless of whether the timing of the reply of the acknowledgment signal to the transmission process is synchronized between the transmitting device 1 and the receiving device 2. The reply of which process of Tx#i (in this example, the reply for the process "0-2"), so that the process "1-2" will not be wrongly retransmitted, and can be retransmitted correctly from the main antenna group Tx#2 Process "0-2".

FIG. 8 shows a flow chart of the operation of the receiving device 2 in the second case.

That is, the receiving device 2 monitors and determines whether a transmission mode switch (change to MIMO diversity transmission) occurs (step S31), and if the transmission mode switch does not occur (step S31: No), the ACK/NACK determination unit 24 An acknowledgment signal to which the received program number is added is generated and returned to the transmitting device 1 . When the acknowledgment signal is a NACK signal, the HARQ reception processing unit 22 maintains the reception process for retransmission synthesis (step S32).

On the other hand, when the transmission mode switching occurs (YES in step S31), the receiving device 2 separates the receiving process (identifies the program number) through the process allocating unit 26 (step S33), and determines whether an antenna identification is added. character (step S34). As a result, if the antenna identifier is attached (step S34 is "yes"), then the receiving device 2 is the same as in the case of the above-mentioned step S32, and adds the received program number and replies an acknowledgment signal to the transmitting device 1, and when the acknowledgment signal is In the case of a NACK signal, the HARQ reception processing unit 22 maintains the reception process for retransmission synthesis (step S35).

On the other hand, when the antenna identifier is not added ("No" in step S34), that is, the transmission device 1 can transmit all processes except the main antenna group Tx#i, and transmits the process while omitting the antenna identifier. In the case of reception, since the addition of the antenna identifier can be omitted, the receiving device 2 does not add the antenna identifier, and uses the sequence number of the main antenna group Tx#2 (the same sequence number as the conventional method in which the antenna identifier is omitted) to transmit The device 1 returns an acknowledgment signal, and when the acknowledgment signal is a NACK signal, the HARQ reception processing unit 22 maintains the receiving process for retransmission synthesis (step S36).

In this way, in this case 2, whenever a transmission mode switch (change to MIMO diversity transmission) occurs, and each transmission process needs to be identified among each antenna group Tx#i (Rx#i), the reception acknowledgment signal is added to the acknowledgment signal. The program number is sent back to the sending device 1, so even if the timing of the reply of the acknowledgment signal for the sending process is not synchronized with the receiving device 2, the sending device 1 can correctly identify the message that should be retransmitted. process, which can reliably suppress erroneous retransmissions of the retransmission process.

Also, in this case 2, all processes other than the main antenna group Tx#2 can be transmitted, and if it is not necessary to identify the transmission process between each antenna group Tx#i (Rx#i), the addition of the transmission antenna is omitted, Therefore, effective use of radio resources between the transmitting device 1 and the receiving device 2 can be realized.

(B) Explanation of the second embodiment

FIG. 9 is a block diagram corresponding to FIG. 2 showing the configuration of a MIMO transmission system according to a second embodiment of the present invention. The MIMO transmission system (transmitter 1 and receiver 2) shown in FIG. 2, the difference lies in that a program number adding unit 17A and a process allocating unit 26A are provided instead of the program number adding unit 17 and process allocating unit 26 described above. In addition, other configurations are the same as or the same as those described in FIG. 1 and FIG. 2. In FIG. 9, they are the same as in FIG. 13) and a part of the components of the receiving device 2 (the CRC calculation unit 22 and the stream compositing unit 25).

Here, the process number adding unit 17A of this example independently adds process numbers to the HARQ blocks (processes) obtained in the HARQ transmission processing unit 14 so that there is no contention among all antenna groups Tx#i. For example, it can be considered that The additional method shown in (1) or (2).

(1) As shown in Fig. 9, add from antenna group Tx#1 to antenna group Tx#n according to ascending order (also can be descending order), after determining the process number for the flow of the last antenna group Tx#n, again The method of adding program numbers in ascending order from the first antenna group Tx#1. That is, the method of adding a sequence of program numbers is repeated for all antenna groups Tx#i. For example, the program number for the antenna group Tx#1 is expressed as "...00000" by a bit string, the program number for the antenna group Tx#n is expressed as "...00111", and the program number following the antenna group Tx#1 The progress number is expressed as "...01000", and the progress number following the antenna group Tx#n is represented as "...01111".

(2) As shown in FIG. 10 , a method of adding an independent (no contention) series of program numbers to each antenna group Tx#i in ascending order (or descending order). For example, the program number of antenna group Tx#1 is "...00000～...00111", the program number of antenna group Tx#2 is "...01000～...01111", and the program number of antenna group Tx#3 is "...01000～...01111". The program number is "...10000～...11111".

That is, the process number adding unit (control unit) 17A of this example also functions as a group-by-group number generating unit in order to achieve the same process number addition control as in the first embodiment without contention between streams. The sequence number information of the group is grouped for each flow, and for each flow, the sequence number information in the corresponding group is provided to the HARQ transmission processing unit 14 as the sequence number (data block identification information) that should be added to the transmission process.

Also, in both cases of (1) and (2) above, in order to avoid the same problems as in the first embodiment, an additional method of sharing a program number between the transmitting device 1 and the receiving device 2 is required.

That is, in order to identify the process number, the process allocation unit 26A of the receiving device 2 stores in advance the process number used in the process number adding unit 17A and the information related to the adding method in a memory not shown in the figure. An additional method for sharing the program number between the sending device 1 and the receiving device 2. Thus, the process allocation unit 26A can identify the process number of the receiving process, and control the signal separation and synthesis processing in the signal separation/combination unit 21 according to the process number, so as to allocate and input the receiving process to each HARQ reception processing unit 22 either of the parties.

Hereinafter, the operation of the MIMO transmission system according to the present embodiment configured as described above will be described with reference to FIGS. 11 to 14 .

First, in the transmitting device 1, the transmission data is separated into the transmission streams of each antenna group Tx#i by the stream separation unit 11, and CRC codes are appended by the corresponding CRC adding units 12, and then encoded into Turbo codes by the encoding unit 13. Wait for the necessary error correction code, and input it into the HARQ transmission processing unit 14.

In the HARQ transmission processing unit 14, HARQ processing (blocking) is performed on the transmission stream input from the encoding unit 13, and as shown in FIG. There is no process number competing among i (step S41 in FIG. 12 ), and the HARQ block (process) is kept for retransmission control, and is transmitted to the transmitting unit 15 .

Thus, the transmission unit 15 performs the above-described wireless transmission processing on the process input from each HARQ transmission processing unit 14, and transmits to the reception device 2 from any one of the transmission antennas Tx#i. Fig. 11 schematically shows this situation. This FIG. 11 is a diagram corresponding to FIG. 3 of the first embodiment, and shows a case where the antenna groups for transmission and reception are each n=2, and the addition method shown in FIG. 9 is applied. The process sent by #1 is sequentially appended with even-numbered program numbers such as "0", "2", and "4", and the process sent from the antenna group Tx#2 is sequentially appended with the program numbers independent of the antenna group Tx#1 (without Competing), odd numbers such as "1", "3", and "5" enter the program number and send it to the receiving device 2 (refer to the situation of the solid line arrow facing downward on the paper in FIG. 9 ).

In addition, in the present embodiment, even after the number of antenna groups to be used decreases as in the case where transmission mode switching occurs (refer to reference numeral 500 in FIG. 11 ), the transmission device 1 maintains the above-described operation of the program number adding unit 17A in the same manner as above. Add method to program number, and perform stream sending.

In the receiving apparatus 2, for example, when the process "4" and the process "5" are received in the case shown in FIG. Therefore, even if transmission mode switching occurs, the HARQ reception processing unit 22 can perform correct combination of processes, that is, combination of processes with the same process number. That is, it is possible to prevent the integrity of the synthesis from being broken (the aforementioned problem 1 can be solved).

In addition, in this embodiment, as in the first embodiment, the ACK/NACK reply method is studied as shown in the following cases 1 and 2, thereby also solving the aforementioned problem 2, that is, the occurrence of a process in the transmission device 1. Error retransmission prevents the process that should have been retransmitted from being retransmitted.

(Case 1) The case of receiving ACK/NACK signal by timing adjustment (Fig. 13)

After switching the transmission mode (change to MIMO diversity transmission) (refer to symbol 500 in FIG. 11 ), the receiving device 2 confirms using (adding) the antenna identifier of each antenna group as in the first embodiment 1. Reply of acknowledgment signal (ACK/NACK). Here, the meanings of "using" and "adding" the antenna identifier are the same as those in the first embodiment.

In addition, after switching to MIMO diversity, in the first embodiment, it means that when the reception device receives a process number without an antenna identifier added, only the process from the main antenna group is transmitted. However, in the second embodiment, since the antenna identifier is not added to the received program number, when a certain period of time (T) elapses, the transmitting device 1 only starts from the main antenna group (referred to as the antenna group in the case of FIG. 11 ). Tx#2) Send process. Therefore, after the time T has elapsed, the receiving device 2 may omit the antenna identifier in reply to the acknowledgment response, and may reply the acknowledgment signal to the sending device 1 only by using the timing information of the main antenna group.

FIG. 13 shows an operation flowchart of the receiving device 2 in this case 1. As shown in FIG.

As shown in FIG. 13 , the receiving device 2 monitors and determines whether a transmission mode switch (change to MIMO diversity transmission) occurs (step S51), and if the transmission mode switch does not occur (step S51: No), the ACK/ The NACK determination unit 24 generates an acknowledgment signal using (added) the antenna identifier, and returns it to the transmitting device 1 . Also, when the acknowledgment signal is a NACK signal, the HARQ reception processing unit 22 maintains the reception process for retransmission synthesis (step S52).

On the other hand, when the transfer mode switching occurs (YES in step S51), the receiving device 2 separates the receiving process (identifies the program number) using the process allocating unit 26A (step S53), and judges whether or not time has elapsed. T (step S54). As a result, if the time T has not elapsed ("No" in step S54), the receiving device 2 generates an acknowledgment signal using (added) the antenna identifier in the same manner as in the above-mentioned step S52, and replies to the transmitting device 1, and When the acknowledgment signal is a NACK signal, the HARQ reception processing unit 22 maintains the reception process for retransmission synthesis (step S55).

On the other hand, if time T has passed (step S54 is "yes"), then the receiving device 2 uses the timing information of the main antenna group to reply an acknowledgment signal to the transmitting device 1, and when the acknowledgment signal is a NACK signal, The reception process is held by the HARQ reception processing unit 22 for retransmission synthesis (step S56).

In this way, in this case 1, when a transmission mode switch (change to MIMO diversity transmission) occurs, as long as it is necessary to identify each transmission process among each antenna group Tx#i (Rx#i), use (additional) Each antenna identifier returns an acknowledgment signal to the transmitting device 1, and can transmit all processes except the main antenna group Tx#2. If it is not necessary to identify each transmission process between each antenna group Tx#i (Rx#i), then Only the timing information of the main antenna group can be used to reply the acknowledgment response, so the effective use of radio resources between the transmitting device 1 and the receiving device 2 can be realized.

(Case 2) A case where an ACK/NACK signal is returned by explicitly adding a program number (Fig. 14)

Even after transmission mode switching (change to MIMO diversity transmission) occurs (refer to symbol 500 in FIG. 11 ), the receiving apparatus 2 explicitly adds a sequence number and returns ACK/NACK. For example, in FIG. 11 , if attention is paid to the process "4" transmitted from the antenna group Tx#1 (the main antenna group is Tx#2) of the transmitting device 1 after transmission mode switching occurs, the receiving device 2 utilizes ACK/NACK The determination unit 24 generates a signal to which the process number of the receiving process “4” is added as a response acknowledgment signal for the process “4”, and returns it to the transmitting device 1 .

Thus, the transmitting device 1 can use the retransmission control unit 16 to recognize that the acknowledgment signal is a reply to which process of which antenna group Tx#i (in this example, a reply to the process "4"), so that Process "5" is retransmitted incorrectly, and process "4" can be correctly retransmitted from the main antenna group Tx#2.

In addition, in this case 2, after a certain period of time (T) elapses after transmission mode switching occurs, the transmitting device 1 only transmits a process from the main antenna group, but the transmitting device 2 cannot omit a process after the elapse of time T Serial number to send the process. In this case 2, even if a certain period of time (T) elapses after transmission mode switching occurs, and the transmission device 1 only transmits the process from the main antenna group, it is different from case 1 and cannot obtain timing synchronization, so it is necessary to add the program number to Reply with an acknowledgment.

FIG. 14 shows a flow chart of the operation of the receiving device 2 in the second case.

That is, the receiving device 2 monitors and determines whether a transmission mode switch (change to MIMO diversity transmission) occurs (step S61), and if the transmission mode switch does not occur (step S61: No), the ACK/NACK determination unit 24 An acknowledgment signal to which the received program number is added is generated and returned to the transmitting device 1 . Also, when the acknowledgment signal is a NACK signal, the HARQ reception processing unit 22 maintains the reception process for retransmission synthesis (step S62).

On the other hand, when transfer mode switching occurs (YES in step S61), the receiving device 2 separates the receiving process (identifies the program number) by the process allocating unit 26A (step S63), regardless of whether the time T has elapsed or not. , all generate the acknowledgment signal added with the received program number, and reply to the transmitting device 1, and when the acknowledgment signal is a NACK signal, the HARQ reception processing section 22 keeps the receiving process for retransmission synthesis (step S66 ).

In this way, in this case 2, when a transmission mode switch (change to MIMO diversity transmission) occurs, as long as it is necessary to identify each transmission process among each antenna group Tx#i (Rx#i), it sends an acknowledgment signal By adding the received program number and replying to the sending device 1, even if the timing of replying to the confirmation response signal to the sending process is not synchronized with the receiving device 2, the sending device 1 can correctly recognize that it should be repeated. The retransmission process can reliably suppress the error retransmission of the retransmission process.

(C) Explanation of the third embodiment

In the above-mentioned first and second embodiments, regarding the method of adding program numbers, it was shown that the number is added so that there is no contention among the antenna groups, so that even when switching from MIMO multiplexing transmission to non-MIMO Even in the case of multiplexed transmission, it is possible to correctly combine processes, prevent erroneous retransmission of processes, and continue stream transmission without interruption. It is also a method that enables continuous communication without interruption of streaming by appending program numbers independently to existing PARC or precoding in the transmitted stream.

In the present embodiment, attention is paid to the occurrence of erroneous retransmission due to processes remaining in antenna groups other than the main antenna group when the transmission mode switching occurs first. Therefore, in order to prevent erroneous retransmission, when switching from MIMO multiplexing transmission to, for example, MIMO diversity transmission, the switching (reduction of the number of streams) is controlled according to the amount of processes (untransmitted processes) remaining in antenna groups other than the main antenna group. ) timing delay (for example, the switching is implemented after the transmissions of the remaining processes are all completed).

FIG. 15 shows the state of communication between the transmitting device 1 and the receiving device 2 when this method is applied. In FIG. 5, FIG. 7, and FIG. 11, when it is detected that the receiving device 2 moves from the MIMO multiplexing transmission area 302 (refer to FIG. 26) to the non-MIMO multiplexing transmission area (MIMO diversity area) 301, 303, the transmitting device In 1, switching to MIMO diversity transmission is implemented immediately (refer to symbol 500).

In contrast, in FIG. 15 , even if the above-mentioned movement (area change) is detected at the timing indicated by symbol 600, since there is a remaining process "2" in the antenna group Tx#1 at this point of time, the transmitting apparatus 1 continues Perform MIMO multiplexing transmission, and actually switch from MIMO multiplexing transmission to MIMO diversity transmission after the transmission of the remaining process "2" ends (for example, the timing indicated by symbol 700). Accordingly, even without using a special process number adding method as in the first and second embodiments, communication can be continued without interrupting streaming when mode switching occurs through simpler control.

However, in this method, the switch to MIMO diversity cannot be made until the retransmission of the remaining process "2" is successful. Therefore, for example, as shown in FIG. 16 , in addition to the switching threshold for MIMO diversity transmission (threshold A for radio quality), a threshold for switching to MIMO diversity even if a process remains is set (threshold B<A for radio quality). And, when the wireless quality of the receiving device (mobile station) 2 is between the threshold A and the threshold B, the transmitting device 1 continues to perform MIMO multiplexing transmission if there are remaining processes, and if the wireless quality is lower than the threshold B, no matter whether there is a process or not. If there is no remaining data, switch to MIMO diversity transmission.

In addition, the above functions may be incorporated as one function of the retransmission control unit 16 described above, for example, or may be incorporated as an independent control unit (transmission mode switching timing control unit). Also, for example, the transmission device 1 can grasp the radio quality of the reception device 2 by using a known method of feeding back reception quality information such as SIR and CQI measured by the reception device 2 to the transmission device 1 (the same applies hereinafter).

(D) Explanation of the fourth embodiment

Here, similar to the above-mentioned third embodiment, another method of continuing stream transmission without interruption in the conventional PARC in which a program number is independently added to a transmission stream for each antenna group is shown.

Also in the fourth embodiment, as in the third embodiment, attention is paid to the occurrence of erroneous retransmission due to processes remaining in antenna groups other than the main antenna group when transmission mode switching occurs. That is, when the mode is switched from MIMO multiplexing transmission to non-MIMO multiplexing transmission (MIMO diversity transmission), the radio quality at the receiving device 2 is larger than the switching threshold (threshold A), but smaller than the other threshold (threshold C) (i.e. threshold C>threshold A>threshold B), and there is no transmission data (process) in the antenna groups other than the main antenna group, the transmitting device 1 does not wait for the wireless quality to become lower than the threshold A, but switches to MIMO diversity transmission.

FIG. 17 shows an example of setting of the thresholds A and C described above. 18 shows the state of communication between the transmitting device 1 and the receiving device 2 when the method of this example is applied.

In FIG. 18, the following situation is shown: after detecting that the receiving apparatus 2 moves from the MIMO multiplexing transmission area to the non-MIMO multiplexing transmission area (MIMO diversity area) (refer to symbol 600), the transmitting apparatus 1 receives The NACK signal of the process "2" of #1 (refer to the dotted line arrow 610), so the retransmission of the process "2" is generated, and after the ACK signal (refer to the solid line arrow 620) for the retransmission process is replied to the sending device 1 , immediately send all remaining processes of antenna group Tx#1. After such a time when there are no remaining processes, if the radio quality of the receiving device 2 is between the threshold A and the threshold C, the transmitting device 1 immediately switches to MIMO diversity transmission at the timing indicated by symbol 700 .

In addition, the above functions may be incorporated as one function of the retransmission control unit 16 described above, for example, or may be incorporated as an independent control unit (transmission mode switching timing control unit). In addition, the above-mentioned threshold A, threshold B, and threshold C may be set simultaneously as long as the relationship threshold C>threshold A>threshold B is satisfied.

Industrial availability

As described above, according to the present invention, in the wireless communication system, even when the number of transport streams between the transmitting device and the receiving device changes (decreases), it is possible to maintain the integration of data blocks to be retransmitted and combined. It is extremely useful in the field of wireless communication technology because it can continue communication normally.

Claims (2)

1. a kind of wireless communication system, wherein the wireless communication system includes：

Sending device has the multiple transmission antennas for the MIMO transmission for executing multiple data blocks；And

Reception device receives the multiple data block,

The sending device is transmitted to the reception device into program number by the control channel different from data channel, it is described into Being associated between value of the program number based on increasing or decreasing in order and data flow, in the sending device and the reception device Between share the association so that it is described not competed between the data block into program number,

When executing MIMO diversity transmissions, the reception device according to described in being received from the sending device into program number, Execute the HARQ processing of the data block received.

2. the wireless communications method in a kind of wireless communication system, wherein the wireless communication system includes：Sending device, tool There are the multiple transmission antennas for the MIMO transmission for executing multiple data blocks；And reception device, the multiple data block is received, In, include the following steps in the wireless communications method：

In the sending device, transmitted to the reception device into program number by the control channel different from data channel, Being associated between value and data flow based on increasing or decreasing in order into program number, connects in the sending device with described The association is shared between receiving apparatus so that it is described not competed between the data block into program number,

In the reception device, when executing MIMO diversity transmissions, the reception device is received according to from the sending device That arrives is described into program number, executes the HARQ processing of the data block received.