JP2008252503A - Retransmission method and transmission device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To retransmit data efficiently by selecting an appropriate modulation method at the time of retransmission, and to synthesize retransmitted data efficiently. <P>SOLUTION: If there is a unit having an error occurred therein in a terminal device 2, a demodulating portion 105 acquires NACK replied by the terminal device 2. A dividing portion 1033 divides data of the unit having an error occurring therein, making each divided part of the data correspond to a node of a tree structure. A unit generating portion 1031 generates division structure information indicating which node of the tree structure each divided part of the data corresponds to, and at the same time, generates a unit for retransmission for retransmitting the data after division including the division structure information. A modulation method selecting portion 1070 selects, among a plurality of modulation methods, a modulation method having a fewer multilevels than the modulation method used when the unit having an error occurring therein has been transmitted and capable of transmitting data of at least a half-size of the unit having an error occurring therein. A modulation executing portion 1034 modulates the unit for retransmission by the selected modulation method and retransmits the modulated unit to the terminal device 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a retransmission technique, and more particularly to a transmission apparatus that performs communication using a plurality of modulation schemes.

  In mobile communication systems, error control techniques for correcting transmission errors are widely used in order to realize high-quality transmission. As one of such error control techniques, there is an automatic repeat request (ARQ) technique. In the automatic retransmission request, the transmission side adds an error detection code to the data and transmits the data to the reception side, and performs error detection processing on the data received on the reception side. When an error is detected, a signal requesting retransmission of data (NACK: Negative Acknowlege) is returned to the transmission side. When receiving the NACK from the receiving side, the transmitting side retransmits the same data and repeats the retransmission until receiving an ACK from the receiving side.

In recent mobile communication systems, as in data communication, in order to realize high-speed and large-capacity data transmission compared to conventional voice communication, the signal modulation method is adaptively changed according to the propagation environment. Adaptive modulation techniques are widely used. Therefore, a technology that combines automatic retransmission request technology and adaptive modulation technology, and when the transmission side receives a NACK from the reception side, it selects a modulation method according to the transmission quality, and modulates and retransmits the same data using this modulation method It has been known. (For example, Patent Document 1)
JP 2006-14197

  However, if retransmission is performed by selecting a modulation scheme according to the transmission quality at the time of retransmission, a modulation scheme with a small amount of information per symbol is used as a modulation scheme for retransmission data as compared to the modulation scheme at the time of transmission of new data. May be selected. Since the amount of information per symbol decreases, the transmission capacity at the time of retransmission decreases. In this case, the transmission side cannot retransmit all the data at once, but separately retransmits the data according to the decrease in the transmission capacity. If the difference in transmission capacity between transmission and retransmission is very small, the amount of data to be retransmitted is considerably smaller than the transmission capacity at retransmission, and the transmission efficiency during separate retransmission is reduced. In addition, due to the influence of the propagation environment, the number of retransmissions increases, and if retransmission is performed with various modulation schemes, the transmission capacity fluctuates each time retransmission is performed, and it becomes necessary to retransmit data separately according to the increase or decrease . For this reason, management of data to be retransmitted separately becomes complicated, and efficient retransmission is difficult.

  The present invention has been made in view of such a situation, and even when the number of retransmissions increases due to the influence of the propagation environment and the transmission quality fluctuates frequently, efficient data retransmission can be performed. An object is to provide a possible transmitter.

  One embodiment of the present invention is a retransmission method. In this retransmission method, when a retransmission request resulting from detection of error data is received from a receiving device, the error data is divided, and a modulation method corresponding to the size of the divided data is selected to perform modulation, and the receiving device The gist of this is to resend it.

  Further, while associating the data that is the origin of the retransmission request with a tree structure having a root as a root, the division is performed, and division structure information that associates the divided data with the tree structure is generated, It is desirable to add the division structure information and retransmit to the receiving apparatus.

  Another aspect of the present invention is a transmission device that transmits data to a reception device. This apparatus combines an acquisition unit that acquires information for specifying error data in which an error has occurred in data received by the receiving device, a division unit that divides error data specified by the information, and the divided data A generating unit that generates information to be used and adds the generated information to the divided data; a selecting unit that selects a multi-level modulation method according to the size of the divided data among a plurality of modulation methods; and the selected modulation method And a retransmission unit that modulates the divided data by using and retransmits the divided data to the receiving apparatus.

  Here, the “multi-level number” includes the amount of information per symbol.

  The division unit executes the division while associating the data that is the origin of the retransmission with a tree structure having a root, and the generation unit associates the divided data with the tree structure node. It is desirable to generate information.

  According to the present invention, the number of retransmissions increases, and even in a propagation environment in which retransmission is performed with various modulation methods when a modulation method corresponding to the transmission quality at the time of retransmission is selected, the portion where the error has occurred is divided. Since a modulation scheme corresponding to the size of the divided data is selected and retransmitted, efficient retransmission can be performed.

  The outline will be described before the present invention is specifically described. The embodiment of the present invention is a base station apparatus that connects a plurality of terminal apparatuses by the TDMA-TDD system, as in the second generation cordless telephone system. In the second generation cordless telephone system, as shown in FIG. 1, a TDMA frame (hereinafter referred to as a TDMA frame) is composed of four time slots for uplink communication (terminal device to base station device) and four time slots for downlink communication (base station device to terminal device). Frame), and the frames are continuously arranged. In the present embodiment, uplink communication and downlink communication are symmetric, and therefore only the downlink communication in which the transmission side is a base station device and the reception side is a terminal device will be described below for convenience of explanation.

  As shown in FIG. 2, the base station apparatus also applies OFDMA (Orthogonal Frequency Division Multiple Access), and allocates a plurality of terminal apparatuses to one time slot. FIG. 2 shows the arrangement of time slots on the time axis in the direction of the horizontal axis, and the arrangement of subchannels on the frequency axis in the direction of the vertical axis. That is, the multiplexing on the horizontal axis corresponds to TDMA, and the multiplexing on the vertical axis corresponds to OFDMA. FIG. 2 includes the first time slot (shown as T1 in the figure) to the fourth time slot (shown as T4 in the figure) in one frame. FIG. 2 includes the first subchannel (indicated as SC1 in the figure) to the eighth subchannel (indicated as SC8 in the figure) in each time slot. In FIG. 2, the terminal device A is on the first subchannel of the first time slot, the terminal device B is on the first subchannel to the fourth subchannel of the second time slot, and the terminal device is on the eighth subchannel of the third time slot. C, and the terminal device D is allocated to the fifth subchannel to the eighth subchannel of the fourth time slot. In the following description, for convenience of explanation, description will be made based on an example in which one terminal device is assigned to one time slot.

  FIG. 3 is a conceptual diagram showing a configuration of a radio channel (hereinafter referred to as a subchannel block) specified by a time slot and a subchannel in FIG. The horizontal direction in FIG. 3 is the time axis, and the vertical direction is the frequency axis. The numbers “1” to “29” indicate subcarrier numbers. In this way, the subchannel is composed of OFDM multicarrier signals. In the figure, “TS” corresponds to a training symbol, and includes known signals such as a symbol “STS” for synchronization detection and a symbol “LTS” for estimation of channel characteristics. “GS” corresponds to a guard symbol, and no effective signal is arranged here. “PS” corresponds to a pilot symbol, and is configured by a known signal. “SS” corresponds to a signal symbol, and a control signal is arranged. “DS” corresponds to a data symbol and is data to be transmitted. “GT” corresponds to a guard time, and no effective signal is arranged.

  FIG. 4 is a conceptual diagram showing a configuration of signal symbols in FIG. The signal symbol includes a modulation parameter notification MI, HARQ control HC, and HARQ response HA. The HARQ control HC includes a HARQ sequence number HARQ SN. The HARQ response HA includes a HARQ ACK sequence number.

  FIG. 5 is a conceptual diagram showing the configuration of the network hierarchy in the embodiment of the present invention. FIG. 5 shows the MAC layer (layer 2) and higher layers. A channel type CI and a MAC layer basic unit PDU (Protocol Data Unit, hereinafter referred to as a unit) are configured from data symbols of one subchannel block shown in FIG.

  FIG. 6 is a conceptual diagram showing the configuration of the unit. The unit includes a retransmission data structure valid flag RSF, a layer 2 data length LEN, a retransmission data structure RTY ST, a layer 2 header including a sequence number PDU SN, layer 2 data in which data is arranged, and an error detection code CRC (Cyclic Redundancy Check). Consists of

  Retransmission control is performed in units of subchannel blocks. In the embodiment of the present invention, since one subchannel block corresponds to one MAC layer unit, HARQ is performed in units of MAC layer units. In the embodiment of the present invention, retransmission control is performed by a hybrid automatic repeat request (HARQ) in which ARQ is combined with FEC (Forward Error Collection). As HARQ, there are known three types of type I, type II, and type III. In the following, for convenience of explanation, type II using a convolutional code and a puncture code will be described as an example.

  One of the factors that the unit cannot receive correctly on the receiving side is a deterioration in communication quality. For this reason, when retransmitting a unit, transmission reliability can be expected to improve by selecting a modulation method with a high error tolerance and a low multi-level number and performing unit modulation.

  At this time, if a modulation method with a small number of multi-values is selected, the transmission capacity per unit is reduced. For example, when changing from a modulation method that can transmit 100-bit data per unit to a modulation method that can only transmit 80-bit data per unit, it is necessary to divide the 100-bit data into 80 bits and 20 bits, and send only 20-bit data. The transmission unit will reduce the transmission efficiency for the remaining 60 bits.

  Therefore, in the base station apparatus according to the embodiment of the present invention, if there is a unit in which an error has occurred on the receiving side, information identifying the unit in which the error has occurred is acquired, and the data of the unit in which the error has occurred is divided. In addition to generating division structure information for synthesizing the division data, a retransmission unit for retransmitting the division data including the division structure information is generated, and a modulation scheme according to the size of the division data is selected for retransmission. The unit was modulated and retransmitted. As a result, it is possible to perform retransmission by selecting a modulation scheme with a small number of multi-values suitable for the data to be retransmitted, so that the efficiency and reliability at the time of data retransmission can be improved.

  FIG. 7 is a conceptual diagram showing the configuration of the mobile communication system 10 according to the embodiment of the present invention. The mobile communication system includes a base station device 1 and a terminal device 2. In FIG. 7, three terminals, ie, the first terminal apparatus 2a, the second terminal apparatus 2b, and the third terminal apparatus 2c, which are collectively referred to as the terminal apparatus 2, are illustrated, but there are two or less terminal apparatuses or four or more terminal apparatuses. May be.

  FIG. 8 is a conceptual diagram showing the configuration of the base station apparatus 1 of FIG. In FIG. 8, an antenna 100 transmits and receives radio frequency signals.

  Radio section 101 performs frequency conversion on a radio frequency signal received by antenna 100 during reception, derives a baseband signal, and outputs the baseband signal to reception section 104. Further, at the time of transmission, the baseband signal from the transmission unit 102 is frequency-converted to derive a radio frequency signal.

  The transmission unit 102 converts the frequency domain signal transmitted from the modulation unit 103 into a time domain signal and outputs the time domain signal to the radio unit 101. Note that IFFT (Inversed Fast Fourier Transform) is used for the conversion from the frequency domain signal to the time domain signal.

  Modulation section 103 modulates the input from IF section 106 and outputs the result to transmission section 102. As a modulation method, BPSK (Binary Phase Shift Keying), QPSK (Quadrature Phase Shift Keying), 16QAM (Quadrature Amplitude Modulation), 32QAM, 64QAM, 256QAM, or the like is used.

  The reception unit 104 converts the time domain signal transmitted from the radio unit 101 into a frequency domain signal and outputs the frequency domain signal to the demodulation unit 105. Note that FFT (Fast Fourier Transform) is used for the conversion from the time domain signal to the frequency domain signal.

  Demodulation section 105 demodulates the input from reception section 104 and outputs the result to IF section. Further, the signal symbol shown in FIG. 4 and the layer 2 header of the unit shown in FIG. 6 are analyzed, and the result is output to the control unit 107.

  The IF unit 7 is connected to a network (not shown), and outputs a signal demodulated by the demodulation unit 105 during reception to a network (not shown). Further, the IF unit 7 inputs data from the network at the time of transmission and outputs it to the modulation unit 103.

  The control unit 107 receives the signal symbol analysis result of the unit sent from the demodulating unit 105 as input, and responds to the terminal device 2 that has returned a NACK to the base station device 1 indicating that the unit cannot be correctly received. Resend data. In addition, the timing of the entire base station apparatus 1 is controlled.

  The control unit 107 receives information sent from a communication quality measurement unit that measures EVM (Error Vector Magnitude), which is a distortion characteristic between an ideal modulation signal and a reception modulation signal, not shown, and sent from the demodulation unit 105. A modulation system selection unit 1070 that receives the unit layer 2 header analysis result as input, selects a modulation system, and controls the modulation unit 103 and the demodulation unit 105 is included.

  The modulation scheme selection unit 1070 records a table showing the relationship between the modulation scheme at the time of transmission and the modulation scheme at the time of retransmission. If it is determined from the signal symbol analysis result that a NACK indicating that the unit cannot be correctly received from the terminal device 2 is returned, the table is referred to, and the data for this unit is retransmitted from the modulation scheme when the unit is transmitted. Determine the modulation method.

  The control unit 107 also includes a division control unit 1071 that controls the unit generation unit 1031, the division unit 1033, and the like to generate a unit for retransmission based on the layer 2 header analysis result of the unit sent from the demodulation unit 105. Including.

  When the division control unit 1071 determines from the signal symbol analysis result that a NACK response indicating that the unit cannot be correctly received from the terminal device 2 has been received, the division unit 1033 divides the data into two, and the unit generation unit 1031 uses the 2 Two new units for resending the divided data are generated. Then, the division control unit 1071 associates the data of the two-division source with the parent and the data after the division into the child each time the data is divided until all the data of the unit that is the starting point of the retransmission is re-transmitted. Then, a tree structure having the root of the data of the unit that is the starting point of the retransmission is formed, and the divided structure information indicating which node of the tree structure corresponds to each divided data.

  FIG. 9 is a conceptual diagram illustrating a detailed configuration of the modulation unit 103. In FIG. 9, the selection unit 1030 selects an input from the IF unit 106 during normal transmission, and an input from the division unit 1033 during retransmission. The unit generation unit 1031 performs convolutional code on the input from the selection unit 1030 and stores the convolutional code in the layer 2 data shown in FIG. 6 and adds a signal symbol, a layer 2 header, and an error detection code CRC to the unit. Generate. In addition, when a specific coding rate is designated, the convolutional code is applied to the input from the selection unit 1030, and the puncture code that thins out the output while referring to a predetermined puncture pattern, and then the layer 2 data To store.

  The transmission buffer 1032 records the data of the unit until the data of the unit that is the starting point of retransmission is correctly received on the receiving side. Further, a predetermined portion of the recorded data is output to the dividing unit 1033 according to an instruction from the dividing control unit 1071. In order to determine whether a unit has been correctly received on the receiving side, the transmission side stores the sequence number assigned to the HARQ SN of the signal symbol of the unit in the HARQ ACK SN of the signal symbol of the paired unit, This is performed based on whether the receiving side has notified within a predetermined time. The dividing unit 1033 divides the output from the transmission buffer 1032 into two and outputs the divided output to the selecting unit 1030. The modulation execution unit 1034 performs modulation such as BPSK on the output from the unit generation unit 1031.

  FIG. 10 shows a data structure of a table showing the relationship between the modulation method at the time of transmission and the modulation method at the time of retransmission recorded by the modulation method selection unit 1070. In FIG. 10, 256QAM or the like represents a modulation method. The fraction attached to the modulation scheme represents the coding rate of the puncture code. The coding rate 1/2 represents that only modulation is performed without performing convolutional code and puncture code. In the table, the modulation scheme that is closest to the half size of the modulation scheme at the time of transmission of information per unit is associated as the modulation scheme at the time of retransmission. With this table, for example, the modulation scheme “64QAM 3/4” at the time of transmission is associated with the modulation scheme “16QAM 3/4” at the time of retransmission.

  FIG. 11 is a conceptual diagram illustrating a configuration of a tree structure of divided data generated by the division control unit 1071. In FIG. 11, each of L = 0 to 4 represents the depth of the tree structure. L = 0 is the route. Further, each of P = 0 to 5... Represents the position from the left end of the tree-structured node having the same depth. P = 0 represents the leftmost position. The division structure information includes a depth of the tree structure (L INFO) and a position from the left end of the tree structure (P INFO). FIG. 11 shows the data of a unit whose modulation method is 256QAM 3/4 as the starting point of retransmission, and shows the modulation method and division structure information of divided data at each retransmission in a tree structure rooted at this data. is there.

  As a specific example of retransmission control, a case where a retransmission request is made for data of a unit whose modulation scheme is 256QAM 3/4 will be described with reference to FIG.

  When the modulation scheme selection unit 1070 determines from the signal symbol analysis result that the terminal device 2 has returned a NACK indicating that the unit whose modulation scheme is 256QAM 3/4 cannot be correctly received, the modulation scheme selection unit 1070 refers to the table of FIG. 64QAM 3/4 is selected as the modulation method for retransmission, and the modulation execution unit 1034 is controlled.

  The division control unit 1071 reads data to be retransmitted from the transmission buffer unit 1032 and sends the data to the division unit 1033. Dividing unit 1033 divides the data into two and outputs the divided data to selecting unit 1030. The division control unit 1071 controls the selection unit 1030 to select the output of the division unit 1033, and the output of the division unit 1033 is sent to the unit generation unit 1031. The unit generation unit 1031 generates two units for retransmitting the data divided into two. The division control unit 1071 assigns L INFO = 001 and P INFO = 00000 as the division structure information to the two divided data corresponding to the left child. On the other hand, L INFO = 001 and P INFO = 00001 are assigned as the divided structure information to the two divided data corresponding to the right child. Then, the generated division structure information is notified to the receiving side by storing L INFO in the upper 3 bits of the RTY ST of the layer 2 header shown in FIG. 6 and P INFO in the lower 5 bits, enabling RSF. Thereafter, the above operation is repeated until there is a notification from the receiving side that all the data of the unit, which is a tree-structured node, has been correctly received. As the split structure information, the depth of the tree structure is 3 bits, the position from the left end of the tree structure is 5 bits, and each 2 split data expresses which node of this tree structure corresponds, but the split structure information It may be expressed uniquely without being divided into depth and position, and the division structure information may be configured with a number of bits other than 8 bits.

  The retransmission control described so far corresponds to a function in the base station apparatus 1. On the other hand, in order to execute retransmission, not only the base station apparatus 1 but also the terminal apparatus 2 needs to execute a predetermined operation. That is, the terminal device 2 performs error detection on the unit data transmitted from the base station device 1, makes a retransmission request to the base station device 1, and combines the divided and retransmitted data. Here, the operation is described as the operation of the terminal device 2, but this function may be included in the base station device 1.

  FIG. 12 is a conceptual diagram illustrating a configuration of functional blocks related to wireless communication of the terminal device 2 of FIG. In FIG. 12, the antenna 200, the transmission unit 202, and the reception unit 204 correspond to the antenna 100, the transmission unit 102, and the reception unit 104 in FIG.

  Modulation section 203 modulates the input from IF section 206 and outputs the result to transmission section 202. Also, the sequence number of the unit determined to have been correctly received by the unit analysis unit 2051 is received from the control unit 207 and stored in the HARQ ACK SN of the signal symbol of the paired unit.

  Demodulation section 205 demodulates the input from reception section 204 and outputs the result to IF section 206. Further, the signal symbol shown in FIG. 4 and the layer 2 header of the unit shown in FIG. 6 are analyzed, and the result is output to the control unit 207.

  The IF unit 206 is connected to a speech decoding unit (not shown) or the like, and outputs a signal demodulated by the demodulation unit 205 at the time of reception to a speech decoding unit (not shown). In addition, IF section 206 inputs data from the voice encoding section at the time of transmission, and outputs this to modulation section 203.

  The control unit 207 receives the signal symbol analysis result of the unit sent from the demodulation unit 205 as an input, and requests the base station apparatus 1 that has transmitted a unit that cannot be received correctly to retransmit the data of the unit. In addition, the timing of the entire base station apparatus 1 is controlled.

  Control section 207 includes a modulation scheme selection section 2070 that determines a modulation scheme with reference to modulation parameter MI included in the signal symbol shown in FIG. 4 and controls modulation section 203 and demodulation section 205.

  The control unit 207 also controls the reception buffer unit 2052, the synthesis unit 2053, and the like to synthesize unit data for retransmission based on the layer 2 header analysis result of the unit sent from the demodulation unit 205. 2071 is included.

  Based on the error detection result sent from the unit analysis unit 2051 and the analysis result of the layer 2 header, the composition control unit 2071 determines whether all the data of the unit that is the starting point of retransmission has been received correctly. If it is determined that all data has been received correctly, the divided data is read from the reception buffer unit 2052 and sent to the synthesis unit 2053. The composition control unit 2071 controls the composition unit 2053 with reference to the division structure information extracted from the RTY ST of the layer 2 header. The synthesizing unit 2053 repeats the operation of synthesizing from the child to the parent in order from the divided data corresponding to the leaf of the tree structure until the root is selected, and finally selects the obtained data as the data of the unit that is the starting point of the retransmission To the unit 2054.

  FIG. 13 is a conceptual diagram illustrating a detailed configuration of the demodulation unit 205. In FIG. 13, the demodulation execution unit 2050 performs demodulation such as BPSK on the output from the reception unit 204. Unit analysis section 2051 extracts and analyzes the layer 2 header from the input from demodulation execution section 2050, and sends the result to control section 207. Further, Viterbi decoding is performed on the data stored in the layer 2 data, it is determined whether an error has occurred using the error detection code CRC, and the result is sent to the control unit 207.

  If no error has occurred, Viterbi-decoded data is extracted. When a specific coding rate is specified, puncture decoding is performed by inserting null data while referring to a predetermined puncture pattern, and Viterbi decoding of the output is performed. Whether or not to perform puncture decoding is determined by referring to the modulation parameter MI included in the signal symbol shown in FIG. 4 and determining whether or not a specific coding rate is designated on the transmission side.

  Further, the unit analysis unit 2051 determines whether or not the unit to be analyzed is for retransmission based on whether or not the RSF of the layer 2 header shown in FIG. 6 is valid. If the unit is a retransmission unit, the data extracted from the layer 2 data is output to the reception buffer 2052. On the other hand, if it is not a unit for retransmission, it is output to the selection unit 2054. The reception buffer 2052 records the retransmitted divided data until all the data of the unit that is the starting point of the retransmission can be correctly received. Further, the recorded divided data is output to the synthesizing unit 2053 according to an instruction from the synthesizing control unit 2071. The synthesizer 2053 synthesizes the output from the reception buffer 2052 in accordance with an instruction from the synthesize controller 2071, and outputs it to the selector 2054. The selection unit 2054 selects an input from the unit analysis unit 2051 at the time of normal reception, and selects an input from the synthesis unit 2053 at the time of completion of retransmission, and outputs it to the IF unit 206.

  The operation of the mobile communication system 10 having the above configuration will be described. FIG. 14 is a flowchart showing a retransmission procedure of the mobile communication system 10.

Based on the measured EVM, the base station apparatus 1 decides the selection of 256QAM 3/4 as the modulation method (S200), and sequences the sequence number “1” to the HARQ SN of the signal symbol and the PDU SN of the layer 2 header. The unit # 1 is generated by storing the number “1” and transmitted to the terminal device 2 (S201). The terminal device 2 performs error detection on the received unit # 1, and determines that this unit has not been received correctly (S202).

Since the base station apparatus 1 has not been notified because the sequence number “1” is stored in the HARQ ACK SN of the signal symbol of the unit paired within a predetermined time (S203), the terminal apparatus 2 receives the NACK of the unit # 1. Is determined to have responded.

Next, the base station apparatus 1 performs retransmission of unit # 1 (S204). This is because if the unit # 1 can be transmitted by retransmission, the transmission efficiency may be improved compared to the case where the data of the unit # 1 is divided into two. The unit # 1 may be retransmitted a predetermined number of times, or may be retransmitted or not depending on the propagation environment such as measured EVM. Here, it is assumed that it is performed only once.

The terminal device 2 performs error detection on the received unit # 1, and determines that this unit has not been received correctly (S205).

Since the base station apparatus 1 has not been notified because the sequence number “1” is stored in the HARQ ACK SN of the signal symbol of the unit paired within a predetermined time (S206), the terminal apparatus 2 determines that the NACK of the unit # 1 Is determined to have responded.

Therefore, the base station apparatus 1 determines the selection of 64QAM 3/4 as the modulation scheme for retransmission with reference to the table of FIG. 10, and divides the data of unit # 1 into two and stores the respective data Generate # 1-1 and unit # 1-2. (S207) Here, the sequence number “1” is assigned to the HARQ SN of the signal symbol of the unit # 1-1, the sequence number “1” is assigned to the PDU SN of the layer 2 header, and the tree structure depth is assigned to the L INFO. “1” is stored in P INFO and the position “0” from the left end of the tree structure is stored. In addition, the sequence number “1” is assigned to the HARQ SN of the signal symbol of unit # 1-2, the sequence number “1” is assigned to the PDU SN of the layer 2 header, and the tree structure depth “1” is assigned to the L INFO. , P INFO stores the position “1” from the left end of the tree structure.

The base station apparatus 1 modulates the unit # 1-1 with 64QAM 3/4 and transmits it to the terminal apparatus 2 (S208). The terminal device 2 detects the error of the received unit # 1-1, determines that this unit has been received correctly, and records it in the reception buffer 2052 (S209). Then, “1” is stored in the HARQ ACK SN of the signal symbol of the paired unit and transmitted to the base station apparatus 1, and the ACK of the unit # 1-1 is returned (S210).

The base station apparatus 1 determines that the unit # 1-1 has been correctly received by the terminal apparatus 2 because the ACK of the unit # 1-1 has been returned from the terminal apparatus 2. Therefore, the unit # 1-2 is modulated by 64QAM 3/4 and transmitted to the terminal device 2 (S211). The terminal device 2 detects the error of the received unit # 1-2, determines that this unit has been received correctly, and records it in the reception buffer 2052 (S212). Then, “1” is stored in the HARQ ACK SN of the signal symbol of the paired unit and transmitted to the base station apparatus 1, and the ACK of the unit # 1-2 is returned (S213).

The base station apparatus 1 determines that the unit # 1-2 has been correctly received by the terminal apparatus 2 because the ACK of the unit # 1-2 has been returned from the terminal apparatus 2. Since it has been confirmed that the terminal device 2 has received all the data of the unit # 1 that is the starting point of the retransmission, the retransmission related to the unit # 1 is completed.

On the other hand, since the terminal apparatus 2 has correctly received all the data of the unit # 1 that is the starting point of the retransmission, the terminal apparatus 2 completes the retransmission request for the unit # 1. Further, the division data of unit # 1-1 and the division data of unit # 1-2 are read from the reception buffer 2052, and are synthesized as data of the parent unit # 1 by the synthesis unit 2053 (S214).

  According to such an embodiment of the present invention, the following operational effects can be enjoyed.

  When there is a retransmission request from the terminal device 2, the demodulation unit 105 acquires a NACK returned from the terminal device 2, the dividing unit 1033 divides the data of the unit in which the error has occurred, and the unit generating unit 1031 And generating a retransmission unit for retransmitting the divided data including the division structure information, and the modulation scheme selection unit 1070 includes a plurality of modulation schemes, The modulation system 1034 selects a modulation system that has fewer multi-values than the modulation system used when the unit in which the error occurred is transmitted and is stored in the reproduction unit, and the modulation execution unit 1034 uses the selected modulation system. Since the unit for reproduction is modulated and retransmitted to the terminal device 2, even if the number of retransmissions increases due to the influence of the propagation environment and the transmission quality fluctuates frequently, the divided data Can be selected with less modulation method multi-level number in accordance with the size, it is possible to improve the efficiency and reliability at the time of data retransmission.

  In addition, the division unit 1033 divides the data of the unit in which an error has occurred in association with the tree structure, and the unit generation unit 1031 generates division structure information for associating the divided data with the nodes of the tree structure. Even when the number of retransmissions increases due to the influence of the above, it becomes easy to manage the divided data associated with the tree structure, and the efficiency at the time of data retransmission can be further improved.

  Although the best mode for carrying out the present invention has been described above, the present invention is not limited to the configuration of this embodiment, and the scope of application of the present invention defined in the claims. As long as the functions of the configuration of the above-described embodiment can be achieved, various modifications are possible.

  For example, in the embodiment of the present invention, the communication system 10 has been described as applying TDMA and OFDMA. However, the present invention is not limited to this. For example, TDMA and CDMA (Code Division Multiple Access) may be applied. And SDMA (Space Division Multiple Access) may be applied.

  In the embodiment of the present invention, HARQ type II has been described as an example of retransmission control. However, the present invention is not limited to this, and for example, random transmission retransmission control such as HARQ type I, type III, or SRARQ (Selective Repeat Automatic Request). May be applied.

Conceptual diagram showing the TDMA frame structure Conceptual diagram showing OFDMA subchannel configuration Conceptual diagram showing the configuration of the subchannel block Conceptual diagram showing the configuration of the signal symbol The conceptual diagram which shows the structure of the network hierarchy in embodiment of this invention Conceptual diagram showing the configuration of the unit The conceptual diagram which shows the structure of the communication system which concerns on embodiment of this invention The conceptual diagram which shows the structure of the base station apparatus which concerns on embodiment of this invention Conceptual diagram showing the detailed configuration of the modulation unit The figure which shows the data structure of the table which showed the relationship between the modulation system at the time of transmission, and the modulation system at the time of retransmission Conceptual diagram showing the structure of the tree structure of divided data The conceptual diagram which shows the structure of the functional block regarding the radio | wireless communication of the terminal device which concerns on embodiment of this invention Conceptual diagram showing a detailed configuration of the demodulation unit 205 Flow chart showing resending procedure

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Radio | wireless part 102 Transmission part 103 Modulation part 104 Reception part 105 Demodulation part 106 IF part 107 Control part 1070 Modulation system selection part 1071 Division | segmentation control part

Claims (4)

  Upon receiving a retransmission request resulting from detection of error data from a receiving device, the error data is divided, and a modulation method corresponding to the size of the divided data is selected, modulated, and retransmitted to the receiving device. A characteristic transmission method. While performing the division while associating the data that is the origin of the retransmission request with a tree structure having a root,
The transmission method according to claim 1, wherein division structure information that associates the division data with the tree structure is added to the division data and retransmitted to the reception apparatus. A transmitting device that transmits data to a receiving device,
An acquisition unit for acquiring information identifying error data in which an error has occurred in the data received by the receiving device;
A dividing unit for dividing the error data identified by the information;
Generating information used to synthesize the divided data, and adding to the divided data;
Among a plurality of modulation schemes, a selection unit that selects a modulation scheme of a multi-level number according to the size of the divided data;
A retransmission unit that modulates the divided data using the selected modulation scheme and retransmits the divided data;
A transmission device comprising: The division unit performs the division while associating with a tree structure having the root of the data that is the starting point of the retransmission,
The transmission apparatus according to claim 3, wherein the generation unit generates division structure information that associates the divided data with the nodes of the tree structure.

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