WO2006082816A1

WO2006082816A1 - Control station apparatus, base station apparatus, and data retransmission method

Info

Publication number: WO2006082816A1
Application number: PCT/JP2006/301583
Authority: WO
Inventors: Hiroki Haga; Atsushi Sumasu; Katsuyoshi Naka; Hidenori Kayama
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2005-02-03
Filing date: 2006-01-31
Publication date: 2006-08-10
Also published as: JP2006217219A

Abstract

A control station apparatus wherein the information of retransmitted data is transferred from a handover source to a handover designation, thereby suppressing the number of retransmissions and preventing the degradation of throughput, while allowing a communication terminal apparatus to perform a correct demodulation in a case of employing the constellation rearrangement. According to this apparatus, a wired transmitting/receiving part (111) outputs the information of a retransmitted data of a base station apparatus (104-1), which is received from a wired transmission path (106-1), to a wired transmission path (106-2), thereby forwarding the information of the retransmitted data of the base station apparatus (104-1) to a base station apparatus (104-2). A handover determining part (112) determines, based on reception quality information of SIR or the like received from the wired transmitting/receiving part (111), whether or not to handover a communication terminal apparatus (105) from the base station apparatus (104-1) to the base station apparatus (104-2).

Description

Control station apparatus, base station apparatus, and data retransmission method

Technical field

TECHNICAL FIELD [0001] The present invention relates to a control station apparatus, a base station apparatus, and a data retransmission method, and more particularly, to a control station apparatus, a base station apparatus, and a data retransmission method that perform handover in a mobile communication system that transmits packet data at high speed.

Background art

[0002] In mobile communication systems, studies on transmission technologies capable of realizing high-speed packet communication are being actively conducted. Especially in 3rd generation mobile communication systems represented by IMT-2000 (International Mobile Telecommunications -2000), the throughput is 10 times higher than the conventional several hundred kbps like HSDPA (High Speed Downlink Packet Access). A study on the high-speed packet transmission technology is underway.

[0003] Specified by 3GPP (3rd Generation Partnership Project)! In HSDPA, when error detection is performed by error correction decoding, a retransmission method (Automatic Repeat reQuest; hereinafter referred to as "ARQ") that requests retransmission of packet data. “Hybrid Automatic Repeat reQuest (hereinafter referred to as“: HARQ ”) is used (for example, Patent Document 1).

[0004] Also, in HSDPA, in order to average bit errors during multi-level modulation such as 16QAM, a constellation rearrangement (Constellation Re-arrangement) that rearranges and transmits bit positions for each retransmission (For example, Non-Patent Document 1).

[0005] When the mobile communication terminal moves between areas covered by the base station (hereinafter referred to as "cell"), the base station performs packet communication performed in the cell before the terminal moves. -Stop and resume packet communication in the cell after the terminal moves. In this way, the base station continues packet communication with the terminal without disconnecting the call. Such stop and restart of communication due to the movement of the terminal between cells is called node or handover.

Patent Document 1: Special Table 2003-534710 Publication

Non-Patent Document 1: 3GPP TS25.212 V6.2.0 (2004-06) "Multiplexing and channel coding" (Section 4.5.7)

Disclosure of the invention

Problems to be solved by the invention

[0006] However, in the conventional apparatus, since retransmission of packet data continues at the handover source base station, the HARQ retransmission information is not inherited at the handover destination base station. The previous base station resets the retransmission and retransmits the retransmitted packet data first. As a result, there is a problem that the total number of times of retransmission including that before handover increases, resulting in a deterioration in throughput. In addition, in the conventional apparatus, the information power of the constellation 'rearrangement bit arrangement pattern, the base station power of the handover source, and the bit arrangement transmitted by the base station of the handover destination are not carried over to the base station of the handover destination. However, there is a problem that the bit arrangement assumed by the communication terminal device is different from that assumed for demodulation, and demodulation is impossible.

[0007] An object of the present invention is to take over the retransmission data information to the handover destination and to reduce the number of retransmissions, prevent the deterioration of the throughput, and reduce the constellation level. The present invention provides a control station apparatus, a base station apparatus, and a data retransmission method that can be correctly demodulated by a communication terminal apparatus when employing an arrangement.

Means for solving the problem

[0008] The control station apparatus of the present invention comprises: a determining unit that determines that the communication terminal apparatus performs handover from the first base station apparatus to the second base station apparatus based on reception quality in the communication terminal apparatus; When the first base station apparatus decides to perform handover during the retransmission process, which is a process of retransmitting data to the communication terminal apparatus, the information on the retransmission process before the handover is And a transfer means for transferring from the base station device to the second base station device.

[0009] The base station apparatus of the present invention, when the communication terminal apparatus is handed over from its own station to another station during the retransmission process, which is a process of retransmitting data to the communication terminal apparatus, before the handover. Transmission means for transmitting the retransmission process information to a higher-level station apparatus, and the retransmission process And a retransmission processing means for stopping the retransmission processing after the transmission means transmits the retransmission processing information to the higher station apparatus.

[0010] Further, the base station apparatus of the present invention is configured such that when the communication terminal apparatus performs handover from the other station to the own station during the retransmission process in which the other station retransmits data to the communication terminal apparatus. In addition, based on the receiving means for receiving the retransmission processing information in the other station before handover and the information on the retransmission processing before handover received by the receiving means, the retransmission processing of the other station And a retransmission control unit that continuously performs the handover after the handover.

[0011] The data retransmission method according to the present invention includes a step of performing a retransmission process, which is a process in which the first base station apparatus retransmits data to the communication terminal apparatus, and based on a reception quality in the communication terminal apparatus 1, A step in which the control terminal apparatus determines that the communication terminal apparatus performs handover from the first base station apparatus to the second base station apparatus, and the communication terminal apparatus performs the first base station apparatus during the retransmission process. The handover from the first base station apparatus to the second base station apparatus when the first base station apparatus transmits the retransmission process information before the handover, and the first base station apparatus performs the retransmission process. Stopping the retransmission process after transmitting the information, and receiving the retransmission process information before the handover transmitted from the first base station apparatus by the control station apparatus; The control station apparatus that has received the retransmission process information before handover transfers the retransmission process information before handover to the second base station apparatus, and the transferred retransmission process information before handover. The second base station device continuously performing the retransmission processing of the first base station device after the handover.

The invention's effect

[0012] According to the present invention, it is possible to suppress the number of retransmissions by taking over the retransmission data information to the handover destination, to prevent the deterioration of the throughput, and to reduce the constellation level. When the arrangement is adopted, the communication terminal device can correctly demodulate.

Brief Description of Drawings FIG. 1 is a block diagram showing a configuration of a mobile communication system according to Embodiment 1 of the present invention.

FIG. 2 is a diagram for explaining handover according to the first embodiment of the present invention.

FIG. 3 is a sequence diagram showing a data retransmission method according to Embodiment 1 of the present invention.

FIG. 4 is a diagram for explaining a data retransmission method according to Embodiment 1 of the present invention.

FIG. 5 is a diagram for explaining a data retransmission method according to Embodiment 1 of the present invention.

FIG. 6 is a block diagram showing a configuration of a mobile communication system according to Embodiment 2 of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

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

[0015] (Embodiment 1)

FIG. 1 is a block diagram showing a configuration of mobile communication system 100 according to Embodiment 1 of the present invention. The mobile communication system 100 includes a server 101, a network 102, a control station device 103, a base station device 104-1 (first base station device), a base station device 104-2 (second base station device), a communication terminal device 105, It consists of a wired transmission line 106-1 and a wired transmission line 106-2. The base station apparatus 104-1 is a handover source base station apparatus covering the cell # 1, and the base station apparatus 104-2 is a handover destination base station apparatus covering the cell # 2. It is. In FIG. 1, two base station devices, base station device 104-1 and base station device 104-2, are connected to control station device 103 via wired transmission paths 106-1 and 106-2. However, the present invention is not limited to this, and the number of base station devices connected to the control station device 103 can be any number.

First, the configuration of control station apparatus 103 will be described using FIG.

The buffer 110 receives downlink packet data transmitted from the server 101 via the network 102, and temporarily stores the received downlink packet data. Then, the noffer 110 accumulates and outputs the downstream packet data to the wired transmission / reception unit 111 at a predetermined timing.

[0018] The wired transmission / reception unit 111, which is a transfer means, reads out the downlink packet data from the nother 110 on the basis of the determination result of whether or not the handover determination unit 112 is capable of handing over, and the wired transmission path 106-1 or Output to cable transmission line 106-2. That is, the wired transmission / reception unit 111 outputs the packet data to the wired transmission path 106-1 before the handover decision, The packet data is transferred from the wired transmission path until the handover is performed after the handover is determined.

Outputs to both 106-1 and wired transmission path 106-2, and outputs the packet data to wired transmission path 106-2 after handover. Also, the wired transmission / reception unit 111 receives the reception quality information, which is the reception quality information of the base station device 104-1 and the base station device 1042, in the communication terminal device 105, which is input from the wired transmission path 106, and performs handover determination. Output to part 112. Furthermore, when the determination result for handover is input from the handover determination unit 112, the wired transmission / reception unit 111 outputs a radio link release request with the communication terminal device 105 to the wired transmission path 106-1, and prepares for handover reception. The request and wireless link establishment request are output to the wired transmission path 106-2.

[0019] Also, the wired transmission / reception unit 111 outputs the retransmission data information of the base station apparatus 104-1 input from the wired transmission path 106-1 to the wired transmission path 106-2, so that the base station apparatus 104 1 The retransmission data information is transferred to base station apparatus 104-2. Here, the retransmission data information includes, for example, a sequence number of packet data in which ACK that is a signal indicating successful reception in communication terminal device 105 is returned, or NACK that is a signal indicating reception failure in communication terminal device 105. This is information such as the sequence number of the returned packet data or the change pattern of the bit arrangement within one symbol of the constellation rearrangement. Note that the retransmission data information includes a sequence number of packet data in which ACK, which is a signal indicating successful reception in communication terminal device 105, and NACK, which is a signal indicating failure in reception in communication terminal device 105, is returned. The packet data sequence number and the information on the change pattern of the bit arrangement in one symbol of the constellation / rearrangement may include two or more.

[0020] The handover determining unit 112, which is a determining unit, performs handover from the communication terminal device 105 to the base station device 104-2 from the base station device 104-1 based on reception quality information such as SIR input from the wired transmission / reception unit 111. It is determined whether or not the power to do. And the handover determination unit

112 outputs the determination result to the wired transmission / reception unit 111.

The control unit 113 controls the wired transmission / reception unit 111.

Next, the configuration of base station apparatus 104-1 as a handover source will be described using FIG. Base station apparatus 104-1 transmits HARQ retransmission method to communication terminal apparatus 105. Resend at.

The wired transmission / reception unit 120 outputs the downlink packet data input from the wired transmission path 106-1 to the buffer 121. Further, the wired transmission / reception unit 120 outputs the information of the retransmission data input from the retransmission control unit 122 to the wired transmission path 106-1. Further, the wired transmission / reception unit 120 outputs the reception quality information of the communication terminal device 105 input from the wireless transmission / reception unit 124 to the wired transmission path 106-1. Also, when a wireless link release request is input from the wired transmission path 106-1, the wired transmission / reception unit 120 outputs the input wireless link release request to the retransmission control unit 122 and the control unit 123.

[0024] The noffer 121 temporarily stores the downlink packet data input from the wired transmission / reception unit 120 and outputs it to the wireless transmission / reception unit 124 and the retransmission control unit 122 at a predetermined timing.

[0025] The retransmission control unit 122 serving as a retransmission processing unit reads packet data that has failed to be received from the buffer 121 by ACK or NACK input from the wireless transmission / reception unit 124, and transmits the packet data to the wireless transmission / reception unit 124 as retransmission data. Output. In addition, when a wireless link release request is input from the wired transmission / reception unit 120, the retransmission control unit 122 stops retransmission processing and transmits information on retransmission data from the start of retransmission to the stop of forced retransmission. Output to transceiver 120.

The control unit 123 controls the wired transmission / reception unit 120 and the wireless transmission / reception unit 124. In addition, when a wireless link release request is input from the wired transmission / reception unit 120, the control unit 123 causes the wireless transmission / reception unit 124 to stop transmission of downlink packet data and retransmission data to the communication terminal device 105. Control.

Radio transmitting / receiving section 124 modulates downlink packet data input from notch 121, up-converts the baseband frequency power to a radio frequency, and transmits it to communication terminal apparatus 105. Radio transmission / reception section 124 modulates retransmission data input from retransmission control section 122 and up-converts it to baseband frequency power radio frequency and transmits it to communication terminal apparatus 105. Also, the wireless transmission / reception unit 124 receives the reception quality information, down-converts the received reception quality information to a radio frequency power baseband frequency, demodulates it, and outputs it to the wired transmission / reception unit 120. In addition, when the wireless transmission / reception unit 124 is controlled by the control unit 123 to stop transmission of downlink packet data or retransmission data First, transmission of downlink packet data or retransmission data is stopped. Radio transmitting / receiving section 124 receives ACK or NACK and outputs the received ACK or NACK to retransmission control section 122.

Next, the configuration of base station apparatus 104-2 as a handover destination will be described using FIG. Base station apparatus 104-2 retransmits to / from communication terminal apparatus 105 using the HARQ retransmission method.

[0029] The wired transmission / reception unit 130 outputs the downlink packet data input from the wired transmission path 106-2 to the buffer 131. In addition, when a handover reception preparation request is input from the wired transmission path 106-2, the wired transmission / reception unit 130 outputs the input handover reception preparation request to the retransmission control unit 132 and the control unit 133. Further, when a wireless link establishment request is input from the wired transmission path 106-2, the wired transmission / reception unit 130 outputs the input wireless link establishment request to the control unit 133. Further, the wired transmission / reception unit 130 outputs the information of the retransmission data input from the wired transmission path 106-2 to the retransmission control unit 132.

[0030] The noffer 131 temporarily stores the downlink packet data input from the wired transmission / reception unit 130, and outputs it to the wireless transmission / reception unit 134 and the retransmission control unit 132 at a predetermined timing.

[0031] Based on the signal indicating the successful reception and the signal indicating the reception failure in communication terminal apparatus 105, which are input from radio transceiver 134, retransmission control section 132 reads packet data that has failed to be received from notifier 131 as retransmission data. Output to the wireless transceiver 134. In addition, when a handover acceptance preparation request is input from the wired transmission / reception unit 130, the retransmission control unit 132 prepares to start retransmission processing. Then, retransmission control section 132 retransmits input from wired transmission / reception section 130 when communication terminal apparatus 105 hands over from cell # 1 of base station apparatus 104-1 to cell # 2 of base station apparatus 104-2. Based on the data information, the retransmission processing in base station apparatus 104-1 is continued.

The control unit 133 controls the wired transmission / reception unit 130 and the wireless transmission / reception unit 134. In addition, when a wireless link establishment request is input from the wired transmission / reception unit 130, the control unit 133 controls the wireless transmission / reception unit 134 to open a wireless line. In addition, when a handover acceptance preparation request is input from the wired transmission / reception unit 130, the control unit 133 performs wireless transmission / reception so as to start transmission of downlink packet data and transmission of retransmission data to the communication terminal device 105. Control part 134.

[0033] When the control unit 133 controls the radio transmission / reception unit 134 to open a radio channel and when it is controlled to start transmission of downlink packet data or retransmission data, the radio transmission / reception unit 134 Open the line and start sending downlink packet data or retransmission data. In this case, the radio transmission / reception unit 134 reads the downlink packet data from the notfer 131, modulates it, up-converts it to the baseband frequency power radio frequency, and transmits it to the communication terminal apparatus 105. Radio transmission / reception section 134 modulates retransmission data input from retransmission control section 132 and up-converts the data to baseband frequency power radio frequency and transmits it to communication terminal apparatus 105. Also, the wireless transmission / reception unit 134 receives the reception quality information, down-converts the received reception quality information to a radio frequency power baseband frequency, demodulates it, and outputs it to the wired transmission / reception unit 130. Radio transceiver 134 receives ACK or NACK, and outputs the received ACK or NACK to retransmission control section 132. Note that the base station device 104-1 and the base station device 104-2 have the same configuration, and the base station device 104-1 and the base station device 104-2 have either processing of the handover source or the handover destination described above. Can also be done.

Next, a data retransmission method in mobile communication system 100 will be described using FIG. 2 and FIG. FIG. 2 is a diagram illustrating handover, and FIG. 3 is a sequence diagram illustrating a data retransmission method.

From FIG. 2, communication terminal apparatus 105 is a cell that is an area covered by base station apparatus 104-1.

It is located near the boundary of # 1 (no, over-over region) and is in cell # 1 at a certain time. Then, in the state of FIG. 2, communication terminal apparatus 105 hands over from base station apparatus 104-1 to base station apparatus 104-2. Cell # 2 is an area covered by base station apparatus 104-2. Further, the base station apparatus 104-1 and the base station apparatus 104-2 are omitted in FIG. 2 for convenience of explanation of the force controlled by the control station apparatus 103 as described above.

From FIG. 3, first, the server 101 transmits downlink packet data to the control station apparatus 103 via the network 102.

Next, the control station apparatus 103 that has received the downlink packet data receives the received downlink packet data. Data is temporarily stored in the buffer 110.

[0038] Next, the wired transmission / reception unit 111 of the control station apparatus 103 reads the downlink packet data stored in the notch 110, and transmits it to the base station apparatus 104-1 via the wired transmission path 106-1. Step ST301).

Next, the wired transmission / reception unit 120 of the base station apparatus 104-1 receives the transmitted downlink packet data and stores it in the buffer 121.

[0040] Next, radio transmitting / receiving section 124 of base station apparatus 104-1 reads the downlink packet data stored in notifier 121, and transmits it to communication terminal apparatus 105 via the radio transmission path (step ST302). ).

Next, communication terminal apparatus 105 that has received the downlink packet data returns ACK to base station apparatus 104-1 because there is no error in the reception result (step ST303).

[0042] In addition, radio transmission / reception section 134 of base station apparatus 104-2 transmits a known signal to communication terminal apparatus 105 using the no-lot channel (step ST304). Radio transmitting / receiving section 124 of base station apparatus 104-1 transmits a known signal to communication terminal apparatus 105 using a pilot channel (step ST305).

Next, communication terminal apparatus 105 that has received the known signal measures the reception quality of base station apparatus 104-1 and base station apparatus 104-2 using the known signal. Communication terminal apparatus 105 transmits the measured reception quality information as reception quality information to base station apparatus 104-1 (step ST306).

[0044] Next, the base station apparatus 104-1 that has received the reception quality information by the wireless reception unit 124 transmits the received reception quality information from the wired transmission / reception unit 120 via the wired transmission path 106-1 to the control station. Transmit to apparatus 103 (step ST307). Note that the processing from step ST301 to step ST307 is repeated. In addition, the timing and number of times of performing each process that can be performed by performing the process of step ST304 to step ST307 during the process of step ST301 to step ST303 can be arbitrarily set.

Next, the control station apparatus 103 that has received the reception quality information selects the base station apparatus 104-2 with good reception quality information as a handover candidate in the handover determination unit 112, and the base station apparatus 104 — 2 is determined to be a no-over candidate. And the control station device 10 The third wired transmission / reception unit 111 transmits a handover acceptance preparation request to the base station device 104-2 selected by the handover determination unit 112 via the wired transmission path 106-2 (step ST308).

[0046] Next, the wired transmission / reception unit 111 of the control station apparatus 103 transmits the downlink packet data read from the notch 110 to the base station apparatus 104-2 via the wired transmission path 106-2 (step S1). ST309), and transmits it to the base station device 104-1 via the wired transmission path 106-1 (step ST310). Thereafter, the control station apparatus 103 transmits the same downlink packet data to the handover candidate base station apparatus 104-2 in the same manner as the communicating base station apparatus 104-1.

Next, the base station apparatus 104-1 that has received the downlink packet data accumulates the received downlink packet data in the buffer 121. Further, the base station device 104-2 that has received the downlink packet data accumulates the received downlink packet data in the buffer 131.

Next, radio transmitting / receiving section 124 of base station apparatus 104-1 wirelessly transmits the lower packet data read from buffer 121 to communication terminal apparatus 105 (step ST311).

Next, communication terminal apparatus 105 that has received the downlink packet data returns a NACK to base station apparatus 104-1 because there is an error in the reception result (step ST312).

[0050] Next, retransmission control section 122 of base station apparatus 104-1 that has received NACK retransmits downlink packet data (step ST313). Thereby, the retransmission process of base station apparatus 104-1 is started.

[0051] Next, communication terminal apparatus 105 that has received retransmission data returns NACK again to base station apparatus 104-1 because there is an error in the reception result (step ST314). Thereafter, transmission of retransmission data is repeated until ACK is returned from communication terminal apparatus 105. The type of retransmission data to be sent at the time of retransmission depends on the HARQ retransmission method. Here, there are three types of HARQ retransmission methods: Type I (Type I), Type II (Type II), and Type III (Type III). However, other retransmission methods may be used.

[0052] In addition, radio transmitting / receiving section 134 of base station apparatus 104-2 transmits a known signal to communication terminal apparatus 105 using the no-lot channel (step ST315). Also, the radio transmission / reception unit 124 of the base station device 104-1 transmits a pilot channel to the communication terminal device 105. Is used to transmit a known signal (step ST316).

Next, communication terminal apparatus 105 that has received the known signal measures the reception quality of base station apparatus 104-1 and base station apparatus 104-2 using the known signal. Communication terminal apparatus 105 transmits the measured reception quality information as reception quality information to base station apparatus 104-1 (step ST317).

[0054] Next, base station apparatus 104-1 that has received the reception quality information at wireless reception unit 124 receives the received reception quality information from wired transmission / reception unit 120 via wired transmission path 106-1, as a control station. Transmit to apparatus 103 (step ST318). It should be noted that the timing and number of times each process can be performed can be arbitrarily set even if the process of step ST315 to step ST318 is performed during the process of step ST311 to step ST314.

Next, control station apparatus 103 that has received the reception quality information causes handover determination section 112 to hand over from base station apparatus 104-1 to base station apparatus 104-2 based on the reception quality information. To decide. For example, when the SIR is used as the reception quality information, the handover determining unit 112 has an SIR in the communication terminal apparatus 105 of the base station apparatus 104-1, which is less than the communication terminal apparatus of the base station apparatus 104-2. If the SIR at 105 is above the threshold! /, The value is determined to be handed over.

[0056] Next, wired transmission / reception section 111 of control station apparatus 103 transmits a radio link release request to base station apparatus 104-1 via wired transmission path 106-1 (step ST319).

[0057] Next, the base station device 104-1 that has received the radio link release request releases the resources allocated to the communication with the communication terminal device 105 in the control unit 123, and sends it to the retransmission control unit 122. To stop sending retransmission data.

[0058] Next, retransmission control section 122 of base station apparatus 104-1 transmits / receives information on retransmission data when retransmission data transmission is stopped, that is, information on retransmission data retransmitted by retransmission processing from step ST313. The data is transmitted to control station apparatus 103 via section 120 and wired transmission path 106-1 (step ST320).

[0059] Next, the control station apparatus 103 that has received the retransmission data information transmits the received retransmission data information to the base station apparatus 104-2 via the wired transmission path 106-2 from the wired transmission / reception unit 111. (Step ST321). [0060] Also, wired transmission / reception section 111 of control station apparatus 103 transmits a wireless link establishment request to base station apparatus 104-2 via wired transmission path 106-2 (step ST322).

Next, the wired transmission / reception unit 111 of the control station apparatus 103 transmits a physical channel setting request to the base station apparatus 104-2 via the wired transmission path 106-2, and sends a physical channel setting request. Receiving base station apparatus 104-2 transmits the received physical channel request to communication terminal apparatus 105 (step ST323).

Next, communication terminal apparatus 105 that has received the physical channel setting request starts reception of packet data after establishing synchronization with base station apparatus 104-2.

[0063] Next, the communication terminal device 105 that has received the physical channel setting request transmits a physical channel setting notification to the base station device 104-2, and the base station device 104-2 that has received the physical channel setting notification receives The received physical channel setting notification is transmitted to control station apparatus 103 via wired transmission path 106-2 (step ST324).

[0064] Next, retransmission control section 132 of base station apparatus 104-2 that has received the information on retransmission data reads packet data from noffer 131 based on the information on retransmission data. That is, retransmission control section 132 continues the retransmission process of base station apparatus 104-1 by continuing the retransmission process at the time of handover of base station apparatus 104-1.

Next, based on the control of retransmission control section 132, radio transmission / reception section 134 of base station apparatus 104-2 transmits the retransmission data read from nofer 131 to communication terminal apparatus 105 (step ST325). ). Thereby, the handover from the base station apparatus 104-1 to the base station apparatus 104-2 is completed.

Next, communication terminal apparatus 105 that has received the retransmission data has an error in the reception result, so N

ACK is returned to base station apparatus 104-2 (step ST326).

[0067] Next, retransmission control section 132 of base station apparatus 104-2 that has received NACK retransmits the downlink packet data (step ST327).

Next, communication terminal apparatus 105 that has received the retransmission data has no error in the reception result.

CK is returned to base station apparatus 104-2 (step ST328). As a result, the retransmission process ends.

[0069] Next, the information on the sequence number of the packet data is the base station device information as the retransmission data information. A data retransmission method when data is transferred from device 104-1 to base station device 104-2 will be described with reference to FIG. 4A is a diagram showing the order of packet data transmitted by the base station device 104-1, and FIG. 4B is a diagram showing the order of packet data transmitted by the base station device 104-2. is there. Note that the left force in Fig. 4 also assumes that time has passed to the right.

[0070] Base station apparatus 104-1 transmits packet data # 402 of sequence number "1" after transmitting packet data # 401 of sequence number "1", and also transmits sequence data of sequence number "1". When packet data # 401 is received from the communication terminal device 105 for ACK for packet data # 401 !, the previous NACK, and bucket data # 402 with sequence number “2”, packet data # 401 with sequence number “1” Is sent as the first retransmission data # 403.

Communication terminal apparatus 105 fails to receive the first retransmission data # 403 of the packet data of sequence number “1” and returns a NACK.

At this time, if the control station apparatus 103 decides to perform handover, the communication terminal apparatus 105 receives the first retransmission data # 403 of the packet data of the sequence number “1”. The information returned from the NACK is transferred as retransmission data information from the base station device 104-1 to the base station device 104-2 via the control station device 103.

The base station device 104-2 that has received the information on the retransmission data transmits second retransmission data # 404 of the bucket data with the sequence number “1”.

Communication terminal apparatus 105 then successfully receives the second retransmission data # 404 of the packet data of sequence number “1” and returns an ACK.

Base station apparatus 104-2 transmits packet data of sequence number “3” and thereafter. Conventionally, when the base station apparatus 104-1 performs handover after transmitting the first retransmission data # 403 of the packet data with the sequence number “1”, the base station apparatus 104-2 It must be retransmitted from the first retransmission data # 403 of packet data “1”. In the case of FIG. 4, the base station apparatus 104-2 does not have to transmit the first retransmission data # 403 of the packet data with the sequence number “1”, and therefore the number of retransmissions can be reduced accordingly. .

[0076] In the above, the ability to transfer the packet data information of the sequence number for which the NACK was returned at the time of handover as the information of the retransmission data is not limited to this. The packet data information of the sequence number to which K is returned may be transferred as retransmission data information. In this case, base station apparatus 104-2 retransmits packet data having a sequence number not included in the retransmission data information. In addition, information on both the packet data of the sequence number to which NACK is returned and the packet data of the sequence number to which ACK is returned may be transferred as retransmission data information at the time of handover. In this case, base station apparatus 104-2 retransmits the packet data of the sequence number for which NACK is returned.

Next, a method for retransmitting data when information on a change pattern of the bit arrangement of constellation rearrangement is transferred from base station apparatus 104-1 to base station apparatus 104-2 as information on retransmission data This will be described with reference to FIG. FIG. 5 (A) is a diagram showing a bit arrangement of packet data transmitted by the base station apparatus 104-1, and FIG. 5 (B) is a bit arrangement of packet data transmitted by the base station apparatus 10 42. FIG. In FIG. 5, it is assumed that one symbol is composed of 4 bits of “a”, “b”, “c”, and “d”. It is assumed that time has passed from left to right in Fig. 5.

[0078] The retransmission control unit 122 of the base station device 104-1 and the retransmission control unit 132 of the base station device 104-2 are arranged with the bit arrangement of "abcd" at the first transmission before retransmission, and "bcda" at the first retransmission. The bit arrangement change pattern of the bit arrangement of “cdab” is stored in the bit arrangement of “” and the second retransmission.

[0079] In this case, base station apparatus 104-1 transmits packet data # 501 having a bit arrangement of "abcd" in one symbol, and NACK for packet data # 501 is transmitted from communication terminal apparatus 105. When it is received, the bit arrangement is changed and packet data having the bit arrangement power of rbcdaj is transmitted as the first retransmission data # 502.

Then, communication terminal apparatus 105 fails to receive retransmission data # 502 and returns NAC K.

At this time, if the control station apparatus 103 decides to perform handover, the information on the bit arrangement change pattern at the first retransmission is transmitted as the retransmission data information via the control station apparatus 103. Thus, the data is transferred from the base station device 104-1 to the base station device 104-2.

[0082] The base station apparatus 104-2 that has received the information on the retransmission data changes the bit arrangement and performs "cda Packet data with bj bit allocation power is transmitted as second retransmission data # 503.

Then, communication terminal apparatus 105 has successfully received retransmission data # 503 and returns ACK. Conventionally, when the base station apparatus 104-1 performs handover after transmitting the first retransmission data # 502, the base station apparatus 104-2 must transmit again from the first retransmission data # 502. . In the case of FIG. 5, since the base station apparatus 104-2 does not have to transmit the first retransmission data # 502, the number of retransmissions can be suppressed accordingly.

[0084] Thus, according to the first embodiment, since retransmission information is carried out by the handover destination information being handed over to the handover source retransmission data, the number of retransmissions can be suppressed, and throughput can be degraded. When the constellation rearrangement is employed, the communication terminal device can correctly demodulate.

[0085] (Embodiment 2)

FIG. 6 is a block diagram showing a configuration of mobile communication system 600 according to Embodiment 2 of the present invention.

[0086] Control station apparatus 601 of mobile communication system 600 according to Embodiment 2 is the same as control station apparatus 103 of mobile communication system 100 according to Embodiment 1 shown in FIG. A retransmission number determination unit 602 is added. In FIG. 6, parts having the same configuration as in FIG.

The wired transmission / reception unit 111 reads the downlink packet data from the noferer 110 based on the determination result of whether or not to perform handover by the handover determination unit 112, and goes to the wired transmission path 106-1 or the wired transmission path 106-2. Output. That is, the wired transmission / reception unit 111 outputs the bucket data to the wired transmission path 106-1 before the handover is determined, and the packet data is transmitted to the wired transmission path 106-1 and the wired transmission path 106-2 after the handover is determined. Output to both sides. Also, the wired transmission / reception unit 111 receives the reception quality information, which is the reception quality information of the base station device 104-1 and the base station device 104-2 in the communication terminal device 105, input from the wired transmission path 106, and performs handover. Output to determination unit 112. Further, when the determination result for handover is input from the handover determination unit 112, the wired transmission / reception unit 111 outputs a wireless link release request with the communication terminal device 105 to the wired transmission path 106-1. At the same time, a handover acceptance preparation request and a wireless link probability request are output to the wired transmission path 106-2.

In addition, wired transmission / reception section 111 outputs information on the number of retransmissions included in the information of retransmission data input from wired transmission path 106-1 to retransmission number determination section 602. Then, when there is an instruction to transfer retransmission data information from retransmission number determination section 602, wired transmission / reception section 111 outputs the retransmission data information of base station apparatus 104-1 to wired transmission path 106-2. As a result, the retransmission data information of base station apparatus 104-1 is transferred to base station apparatus 104-2. Here, the retransmission data information includes, for example, the sequence number of the packet data for which ACK is returned, the sequence number of the packet data for which NACK is returned, or the bit arrangement within one symbol of the constellation 'rearrangement. In addition to pattern information, etc., information on the number of retransmissions is included. The retransmission data information includes a sequence number of packet data for which ACK, which is a signal indicating successful reception in communication terminal device 105, and NACK, which is a signal indicating failure in reception in communication terminal device 105, are returned. Even if the packet data contains the sequence number of the packet data, the information on the change pattern of the bit arrangement in one symbol of the constellation 'rearrangement, and more than one of them and the information on the number of retransmissions good.

The retransmission number determination unit 602 compares the number of retransmissions with a threshold value based on the information on the number of retransmissions input from the wired transmission / reception unit 111. Then, when the number of retransmissions is equal to or greater than the threshold value, retransmission number determination unit 602 controls wired transmission / reception unit 111 so as not to transfer retransmission data information to base station apparatus 104-2. When the number of times is less than the threshold value, the wired transmission / reception unit 111 is controlled to transfer the information on the retransmission data to the base station device 104-2.

[0090] Retransmission control section 132 reads packet data that has failed to be received from receiver 131 from the signal indicating successful reception and the signal indicating reception failure in communication terminal apparatus 105, which are input from radio transmission / reception section 134, as retransmission data. Output to the wireless transceiver 134. In addition, when a handover acceptance preparation request is input from the wired transmission / reception unit 130, the retransmission control unit 132 prepares to start retransmission processing. Then, retransmission control section 132 has communication terminal device 105 transferred from cell # 1 of base station device 104-1 to cell # 2 of base station device 104-2. If retransmission data information is input from the wired transmission / reception unit 130 in the event of a handover, the retransmission processing in the base station device 104-1 is continued based on the retransmission data information input from the wired transmission / reception unit 130, and If retransmission data information is not input from the transmission / reception unit 130, retransmission processing is restarted from the beginning. The data retransmission method is the same as that shown in FIG. 3 except that it is selected whether to continue the retransmission process or start again from the beginning according to the number of retransmissions, and a description thereof will be omitted.

[0091] The reason for selecting whether to continue the retransmission process according to the number of retransmissions or to start over from the beginning is that the packet data that already has a large number of retransmissions at the time of handover decision has an error rate due to poor reception quality, etc. It is considered large. In this state, even if the retransmission control information is handed over to the node, the throughput improvement effect is not expected. Therefore, in the second embodiment, when the number of retransmissions is equal to or greater than the threshold, the retransmission data information is reset, and when the number of retransmissions is not equal to or greater than the threshold, the retransmission is performed as in the first embodiment. Communicate by taking over data information.

As described above, according to the second embodiment, in addition to the effect of the first embodiment, when the number of retransmissions is threshold //, the retransmission processing is re-executed from the beginning when the value is greater than or equal to the value. The number of times can be reliably suppressed, and when the constellation rearrangement is employed, the communication terminal device can reliably demodulate.

Note that in Embodiment 1 and Embodiment 2 described above, the ability to use HARQ as the retransmission scheme is not limited to this, and an arbitrary retransmission scheme can be used.

[0094] This specification is based on Japanese Patent Application No. 2005-27428 filed on Feb. 3, 2005. All this content should be included here.

Industrial applicability

The control station apparatus, base station apparatus, and data retransmission method according to the present invention are suitable for use in a mobile communication system that transmits packet data at high speed.

Claims

The scope of the claims

[1] A determining unit that determines that the communication terminal apparatus performs handover from the first base station apparatus to the second base station apparatus based on reception quality in the communication terminal apparatus;

When it is determined that the first base station apparatus performs handover by the determining means during the retransmission process, which is a process of retransmitting data to the communication terminal apparatus, information on the retransmission process before the handover is obtained. Transfer means for transferring from the first base station device to the second base station device;

A control station apparatus comprising:

[2] When the number of retransmissions is less than a threshold, the transfer unit transfers the retransmission processing information before the handover to the second base station apparatus, and the number of retransmissions is equal to or more than the threshold! 2. The control station apparatus according to claim 1, wherein in this case, the information on the retransmission process before handover is not transferred to the second base station apparatus.

[3] The transfer means uses the sequence number of packet data to which a signal indicating successful reception is returned or the sequence number of packet data to which a signal indicating reception failure is returned as information on the retransmission processing before handover. The control station apparatus according to claim 1, which is transferred.

4. The control station apparatus according to claim 1, wherein the transfer means transfers information on a bit arrangement change pattern in one symbol that is changed for each retransmission as information for the retransmission process.

[5] When the communication terminal apparatus is handed over to its own station or another station during the retransmission process, which is a process of retransmitting data to the communication terminal apparatus, information on the retransmission process before the handover is sent to the upper station apparatus. A transmission means for transmitting;

A retransmission processing means for performing the retransmission processing and stopping the retransmission processing after transmitting the retransmission processing information to the upper station apparatus by the transmission means;

A base station apparatus comprising:

[6] When the communication terminal apparatus performs handover from the other station to the own station during the retransmission process in which the other station retransmits data to the communication terminal apparatus, Receiving means for receiving information of the retransmission process;

Based on the information on the retransmission process before the handover received by the receiving means, the retransmission control means for continuously performing the retransmission process of the other station after a node over; A base station apparatus comprising:

Performing a retransmission process, which is a process in which the first base station apparatus retransmits data, to the communication terminal apparatus;

Based on the reception quality in the communication terminal device, the control station device determines that the communication terminal device is handed over from the first base station device to the second base station device;

When it is determined that the communication terminal apparatus is to be handed over from the first base station apparatus to the second base station apparatus during the retransmission process, information on the retransmission process before the handover is transmitted to the first base station apparatus. Sending from

Stopping the retransmission processing after the first base station apparatus transmits the information on the retransmission processing;

The control station apparatus receiving the retransmission process information before handover transmitted from the first base station apparatus;

The control station apparatus that has received the retransmission process information before the handover transfers the retransmission process information before the handover to the second base station apparatus, and the transferred retransmission process information before the handover The second base station device continuously performs the retransmission processing of the first base station device after handover, and

A data retransmission method comprising: