JP2009302864A - Mobile terminal and data transmission method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To dissolve the following problem: a data transmission result retransmitted in the first time from a mobile terminal becomes NACK when a receiving result notified from a base station can be determined neither as ACK nor as NACK in data transmission on an E-DPDCH (Enhanced Dedicated Physical Data Channel) of an HSUPA (High Speed Uplink Packet Access). <P>SOLUTION: A rate matching part 12 of a mobile communication terminal 6 performs rate matching of data encoded by a channel encoding part 11 based on a rate matching parameter for first transmission when the data is retransmitted when the receiving result notified from the base station in the first data transmission can be determined neither as ACK nor NACK. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mobile terminal apparatus and a data transmission method for transmitting transmission data to a base station on an enhanced dedicated channel (E-DCH) of high speed uplink packet access (HSUPA).

  FIG. 1 shows a conventional data transmission flow on the E-DCH. In step S10, the mobile terminal apparatus transmits an enhanced dedicated physical data channel (E-DPDCH) to the base station via the enhanced dedicated physical control channel (E-DPCCH). Control information such as the format is transmitted, and in step S11, the mobile terminal apparatus transmits data to the base station via the E-DPDCH.

  In steps S12 and S13, the base station decodes the signal received via the E-DPCCH and E-DPDCH, and in step S15, the base station receives the reception result as an E-DCH HARQ confirmation indication channel (E-HICH: E-DCH). It is transmitted to the mobile terminal apparatus via the HARQ Acknowledgment Indicator Channel). At this time, the base station transmits ACK as the reception result if the decoding result of E-DPDCH is normal, and transmits NACK if the decoding result of E-DPDCH is abnormal.

  In addition to the case where the base station transmits ACK or NACK, the base station may transmit neither ACK nor NACK. For example, if the decoding result of E-DPCCH is abnormal, the base station discards the reception result of E-DPDCH in step S14, and neither ACK nor NACK is transmitted on E-HICH in S15. In this way, a state in which neither ACK nor NACK is transmitted from the base station may be described as “DTX” hereinafter.

The mobile terminal apparatus soft-combines received signals received on one or more base stations on E-HICH for each base station, and then the reception result of the previously transmitted data is ACK or NACK. Determine whether. At this time, when the mobile terminal apparatus receives reception results from a plurality of base stations, if even one of these base stations receives an ACK, the mobile terminal apparatus determines ACK and transmits the next data, In other cases, NACK is determined and the previously transmitted data is retransmitted.
At this time, if the decoding results of E-DPCCH are abnormal in all radio links, the contents of the reception results transmitted on E-HICH of these radio links are all DTX (step S16), As a result, the base station retransmits the previously transmitted data (steps S17 and S18).

  In Patent Document 1 below, when user data retransmission control is performed in a physical layer and a MAC sublayer between a mobile station and a base station, Ack-DTX determination is performed according to the number of radio base stations to which the mobile station is connected. Setting a threshold is disclosed.

JP 2006-295912 A

  Data transmitted from the mobile terminal device to the base station is channel-coded by turbo coding processing, and the size of the data channel-coded by rate matching processing is matched with the data size of the transmission channel. The value of the rate matching parameter that determines the rate matching process is determined by the number of retransmissions, and when transmitting the data for the first time, i.e., when the data is transmitted for the first time, the systematic bits have priority over the turbo encoded channel encoded data. In the first retransmission, the parity bit is determined to be transmitted with priority over the systematic bit. For this reason, the data retransmitted in steps S17 and S18 of the flow shown in FIG.

  However, if, for example, the decoding result of E-DPCCH is abnormal, the data at the time of initial transmission is discarded on the base station side in step S14, the E-DPCCH and the data are temporarily stored in steps S19 and S20. Even if the signal on the E-DPDCH can be normally decoded, transmission data before encoding cannot always be decoded under a predetermined condition (step S21). In particular, if the data size before channel coding and the data size of the data transmitted on the physical channel are approximately the same, the amount of information is not sufficient with only the retransmitted parity bits. Cannot decrypt.

  As a result, even if data is retransmitted in steps S17 and S18, a NACK is transmitted as a reception result (step S22), and the mobile terminal apparatus that has received the NACK in step S23 performs a second retransmission in steps S24 and S25. It must be.

  The disclosed apparatus and method solve the problem that the data transmission result retransmitted first time is always NACK when the reception result notified from the base station cannot be determined as ACK or NACK as described above. Objective.

  In the disclosed apparatus and method, when the reception result notified from the base station at the first data transmission cannot be determined as either ACK or NACK, when the data is transmitted again, the rate matching parameter for initial transmission is set. Based on the rate matching process.

  The rate matching parameter for initial transmission may be used when ACK and NACK cannot be determined for any base station connected to the mobile terminal device via a radio link. In addition, when no ACK signal is detected for any base station and the communication quality with the base station from which the NACK signal is detected satisfies a predetermined standard, the rate matching parameter for initial transmission is used. Also good.

When the reception result notified from the base station cannot be determined as ACK or NACK, the problem that the second data transmission result is always NACK is solved, and the data throughput in the uplink between the mobile terminal apparatus and the known station is solved. Is improved.
Even if NACK is received from any of the base stations, when the communication quality with these base stations satisfies a predetermined standard, a more reliable radio link is obtained by using a rate matching parameter for initial transmission. It is possible to determine which rate matching parameter for initial transmission or retransmission should be used according to the reception result information obtained from the connected base station.

Hereinafter, embodiments will be described with reference to the accompanying drawings. FIG. 2 is a schematic configuration diagram of the disclosed communication system. The communication system 1 is a communication system that supports HSUPA, and includes a core network 2 including a packet switching network and a circuit switching network, a radio network controller 3 (RNC) connected to the core network 2, and a radio network controller R3. And base stations 4 and 5 connected to the mobile terminal device 6 (UE).
In the illustrated example, the base station 4 covers a plurality of cells C1 to C3, and the mobile terminal device 6 and the base station 4 are simultaneously connected by a plurality of radio links RL1 and RL2. The base station 5 covers a plurality of cells C4 and C5, and the mobile terminal device 6 is connected to the base station 5 as well as the base station 4. The radio link between the mobile terminal device 6 and the base station 5 is indicated by the reference symbol RL3.

FIG. 3 is a schematic configuration diagram of the disclosed mobile terminal apparatus. The configuration diagram of FIG. 3 describes only the functions related to the description of the data retransmission function and the retransmission method disclosed in this specification among the functions provided as a mobile terminal apparatus supporting HSUPA, and supports HSUPA. Description of other functions that the mobile terminal device 6 should have as a mobile terminal device to be performed is omitted.
The mobile terminal apparatus 6 generates a baseband processing unit 10 for generating or processing transmission data, and performs turbo encoding processing on transmission data output from the baseband processing unit 10 to perform channel encoded data (S, P1, P2). The channel encoding unit 11 for generating the channel encoded data (S, P1, P2) is subjected to rate matching processing including puncturing processing and repetition processing, and the size of the channel encoded data is set to the data size of the transmission channel. A rate matching unit 12 that generates transmission data according to the transmission rate, a transmission unit 13 that transmits transmission data via E-DPDCH, and control information such as a transmission format of E-DPDCH via E-DPCCH, and rate matching. The rate matching parameter that determines the operation of the rate matching process performed by the unit 12 It includes a parameter setting unit 14 for a constant, a.

  In addition, the mobile terminal device 6 receives, with respect to the reception result of the data transmitted via the E-DPDCH, the reception unit 15 that receives the reception result information transmitted from the base stations 4 and 5 via the E-HICH, and the reception unit 15 A reception result detection unit 16 that detects an ACK signal or a NACK signal transmitted from the base stations 4 and 5 based on the reception signal received by the unit 15 is provided. The reception quality measurement unit 17 will be described later.

  The reception result detection unit 16 detects these signals by despreading the ACK signal or NACK signal spread by the base stations 4 and 5 with a predetermined spreading code, and receives the reception result information received from the base stations 4 and 5. Is ACK, NACK, or DTX which is neither of these, the parameter setting unit 14 is notified.

  When the reception result detection unit 16 detects the NACK signal, the parameter setting unit 14 performs rate matching for retransmission to the rate matching unit 12 that performs rate matching processing on the previously transmitted channel encoded data (S, P1, P2).・ Set the parameters. The rate matching unit 12 in which the rate matching parameters for the first retransmission are set generates transmission data by giving priority to the parity bits P1 and P2 that are error correction codes.

  On the other hand, when the reception result detection unit 16 detects neither an ACK signal nor a NACK signal, that is, in a state of DTX, the parameter setting unit 14 performs rate matching processing on the previously transmitted channel encoded data (S, P1, P2). The rate matching parameter for initial transmission is set in the rate matching unit 12 that performs the above. The rate matching unit 12 to which the rate matching parameter for initial transmission is set generates transmission data with priority given to the systematic bit S.

In particular, when the data length of the transmission data transmitted through the physical channel is substantially the same as the data length before encoding, the data length of the channel encoded data after turbo encoding is approximately three times the data length of the transmission data. It becomes.
At this time, the transmission data generated by the rate matching unit 12 in which the rate matching parameter for the first retransmission is set is data including approximately 50% of the parity bits P1 and P2, and the original transmission data is There is always a lack of data to reproduce. Therefore, the original data cannot be reproduced on the base station side only from the retransmitted data.

On the other hand, the transmission data generated by the rate matching unit 12 in which the rate matching parameter for initial transmission is set includes at least all systematic bits. Therefore, the original transmission data is reproduced only from this data. be able to. In this way, the disclosed apparatus and method improve the throughput by increasing the possibility that the reception result of the data retransmitted at the first time becomes ACK and avoiding the second retransmission.
In the disclosed apparatus and method, the transmission data output by the rate matching unit 12 in which the rate matching parameter for the first retransmission is set does not include all information necessary for reproducing the original transmission data. Good effect in case. Therefore, a particularly good effect is exhibited when the ratio of the data length before encoding to the data length of transmission data transmitted through the physical channel is about 1 to 1/2.

FIG. 4 is a diagram illustrating a data transmission flow on the E-DCH according to the disclosed data transmission method. Steps S10 to S16 are the same as the flow described with reference to FIG.
The reception unit 15 of the mobile terminal device 6 receives a signal indicating the reception result transmitted from the base stations 4 and 5 via E-HICH. In step S16, the reception result detection unit 16 decodes the received signal and transmits an ACK. A signal or a NACK signal is detected.

When the reception result detection unit 16 detects a NACK signal in any of the currently connected radio links, the parameter setting unit 14 generates a rate matching parameter for the first retransmission as in the conventional case. .
When the reception result detection unit 16 does not detect the ACK signal or the NACK signal in any of the currently connected radio links, the reception result detection unit 16 is in the DTX state in which neither the ACK signal nor the NACK signal is detected. The parameter setting unit 14 is notified of this, and in step S30, the parameter setting unit 14 generates a rate matching parameter for initial transmission.

  The rate matching unit 12 generates transmission data including data for initial transmission including the systematic bit S preferentially in accordance with the rate matching parameter for initial transmission generated by the parameter setting unit 14, and the E-DPCCH and Transmission data is transmitted to the base station via the E-DPDCH (steps S31 and S32).

  In the base stations 4 and 5, if the received data can be normally decoded (steps S33 and S34), the received data includes all information for reproducing the original data before channel coding. The data can be reproduced. Therefore, unlike the conventional flow described with reference to FIG. 1, the base stations 4 and 5 can transmit the ACK signal to the mobile terminal apparatus 6 without requesting the second retransmission (step S36). The receiving unit 15 and the reception result detecting unit of the mobile terminal device 6 receive and decode the ACK signal, respectively, and the transmission process of the data is completed.

In the above embodiment, when the reception result is DTX in all the radio links connecting the base stations 4 and 5 and the mobile terminal device 6, the transmission data for the initial transmission is transmitted again.
However, for example, if the determination result in Serving RL, which is a radio link connecting the most reliable communication base station, is DTX, even if the determination result in Non-Serving RL is NACK However, it is possible to reduce the second retransmission by transmitting the transmission data for the first transmission again.

Therefore, the mobile terminal apparatus 6 shown in FIG. 3 includes a reception quality measurement unit 17 that measures reception quality in the currently connected radio link.
For example, the reception quality measurement unit 17 may measure the SIR (reception signal power to interference power ratio) of the reception radio wave detected by the reception unit 15 as the reception quality. Further, the bit error rate of the received data may be measured as the reception quality.

When the reception result detection unit 16 does not detect that the ACK signal has been received from any of the connected base stations, the parameter setting unit 14 receives the reception quality index measured by the reception quality measurement unit 17 for each base station. When the reception quality measured for the base station from which the NACK signal is detected satisfies a predetermined standard, a rate matching parameter for initial transmission is set in the rate matching unit 12.
On the other hand, when it is not detected that an ACK signal has been received from any of the connected base stations and the reception quality measured for the base station from which the NACK signal is detected does not satisfy the predetermined criterion, rate matching is performed. A rate matching parameter for the first retransmission is set in the unit 12.

FIG. 5 is a flowchart illustrating a data retransmission procedure in the disclosed data transmission method.
In step S50, the mobile terminal apparatus 6 transmits data for the first time to the base station. At this time, the rate matching unit 12 performs rate matching of the channel encoded data using the rate matching parameter for initial transmission.
In step S51, the base station determines the reception result transmitted in step S50. If the reception results transmitted from all the base stations currently connected by the radio link are ACK, the mobile terminal apparatus 6 moves the process to S50 and performs the first transmission of the next data.

If there is a base station whose reception result is not ACK among the base stations currently connected by the radio link, the reception quality measurement unit 17 determines the quality of the reception signal detected by the reception unit 15 in each base station in step S52. Measure every time. The reception quality measuring unit 17 determines an index of reception quality for each base station.
For example, the index may be obtained as the ratio of the measurement value of the reception quality from each base station to the measurement value of the reception quality from the base station having the highest reception quality.

  For the following description, for example, the mobile terminal device 6 is connected to four base stations BS0 to BS3, and the indices determined for the base stations BS0 to BS3 are 1.0, 0.75, 0.5, respectively. And 0.1, and the reception results by the base stations BS0 and BS1 are DTX, and the reception results by the base stations BS2 and BS3 are NACK.

  In step S53, the parameter setting unit 14 calculates the total value of the reception quality indices in other base stations other than the base station whose reception result is determined to be DTX. In the above example, since the reception results by the base stations BS2 and BS3 are not DTX, the total value (0.5 + 0.1 = 0.6) of the reception quality indices at these base stations is calculated.

In step S54, it is determined whether or not the total value calculated in step S53 is less than a predetermined threshold value.
As a result of the determination, if the total value is less than the predetermined threshold value, it is considered that the reception quality at the base station (base stations BS2 and BS3 in this example) whose reception result is not DTX is lower than an allowable value. For this reason, the reception result by these base stations is not adopted, and the parameter setting unit 14 sets the rate matching parameter for initial transmission in the rate matching unit 12 in step S55. For this reason, transmission data for initial transmission is transmitted again to the base stations BS0 to BS3.
For example, in the above example, if the threshold value is preset to 0.625, the total value 0.6 calculated in step S53 is smaller than the threshold value, so the process moves to step S55, and the transmission data for the initial transmission is stored. It is transmitted again to the base stations BS0 to BS3.

  On the other hand, if the result of determination in step S54 is that the total value is less than the predetermined threshold value, it is considered that the reception quality at the base stations whose reception results are not DTX (base stations BS2 and BS3 in this example) satisfies the allowable value. . For this reason, in step S56, the parameter setting unit 14 sets the rate matching parameter for the first retransmission in the rate matching unit 12. For this reason, the transmission data for the first retransmission is transmitted again to the base stations BS0 to BS3.

  The following additional notes are further disclosed with respect to the embodiment including the above examples.

(Appendix 1)
A mobile terminal apparatus that transmits transmission data to a base station on an enhanced dedicated physical data channel (E-DPDCH) of high-speed uplink packet access (HSUPA),
A rate matching unit that generates transmission data by puncturing channel encoded data of the transmission data according to a rate matching parameter determined according to whether transmission of the transmission data is initial transmission or retransmission;
A transmission unit for transmitting the transmission data to a base station;
A reception result detection unit for detecting an ACK signal or a NACK signal transmitted from the base station with respect to the reception result of the transmission data;
For the transmission data transmitted at the time of the initial transmission of the transmission data, when the reception result detection unit detects neither an ACK signal nor a NACK signal, rate matching of the channel encoded data for transmitting the transmission data again A parameter setting unit that sets a rate matching parameter for initial transmission as the rate matching parameter used for
A mobile terminal device comprising: (1, Fig. 3)

(Appendix 2)
The mobile terminal apparatus according to supplementary note 1, wherein the rate matching unit generates the transmission data including an error detection code when a rate matching parameter for retransmission is designated.

(Appendix 3)
The parameter setting unit, when neither an ACK signal nor a NACK signal is detected for any base station connected to the mobile terminal device via a radio link, the rate matching when transmitting the initial transmission data again. The mobile terminal device according to attachment 1, wherein a rate matching parameter for initial transmission is set as a parameter. (2, Fig. 4)

(Appendix 4)
A communication quality measuring unit for measuring communication quality between the mobile terminal device and the base station;
When no ACK signal is detected for any base station connected to the mobile terminal device through a radio link and the communication quality with the base station from which the NACK signal is detected satisfies a predetermined standard, the initial transmission The mobile terminal apparatus according to appendix 1, wherein a rate matching parameter for initial transmission is set as the rate matching parameter when transmitting transmission data again. (3, Fig. 5)

(Appendix 5)
A method for transmitting data from a mobile terminal apparatus to a base station on an enhanced dedicated physical data channel (E-DPDCH) of high-speed uplink packet access (HSUPA),
In accordance with a rate matching parameter determined according to whether transmission of transmission data is initial transmission or retransmission, the channel encoded data is subjected to rate matching processing by puncturing the channel encoded data of the transmission data,
Transmitting transmission data obtained by puncturing the encoded data to a base station;
Detecting an ACK signal or a NACK signal transmitted from the base station with respect to a reception result of the transmission data;
For the transmission data transmitted at the time of initial transmission of the transmission data, when neither an ACK signal nor a NACK signal is detected, in order to transmit the transmission data again, based on the rate matching parameter for initial transmission, A data transmission method characterized by performing the rate matching processing of channel encoded data. (4, Fig. 4)

(Appendix 6)
The data transmission method according to appendix 5, wherein the rate matching processing generates the transmission data including an error detection code when a rate matching parameter for retransmission is designated.

(Appendix 7)
When neither an ACK signal nor a NACK signal is detected for any base station connected to the mobile terminal device through a radio link, the rate matching process of the channel coded data is performed based on a rate matching parameter for initial transmission. The data transmission method according to attachment 5, wherein:

(Appendix 8)
Measure the communication quality between the mobile terminal device and the base station,
When no ACK signal is detected for any base station connected to the mobile terminal device via a radio link and the communication quality with the base station from which the NACK signal is detected satisfies a predetermined standard, The data transmission method according to appendix 5, wherein the rate matching processing of the channel encoded data is performed based on a rate matching parameter. (Fig. 5)

It is a figure which shows the conventional data transmission flow on E-DCH. It is a schematic block diagram of the communication system of an indication. It is a schematic block diagram of the mobile terminal device of an indication. It is a figure which shows the data transmission flow on E-DCH by the data transmission method of an indication. It is a flowchart which shows the data resending procedure in the data transmission method of an indication.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Communication system 2 Core network 3 Wireless network control device 4, 5 Base station 6 Mobile terminal device C1-C5 Cell RL1-RL3 Wireless link

Claims (4)

A mobile terminal device that transmits transmission data to a base station on an enhanced dedicated physical data channel for high-speed uplink packet access,
A rate matching unit that generates transmission data by puncturing channel encoded data of the transmission data according to a rate matching parameter determined according to whether transmission of the transmission data is initial transmission or retransmission;
A transmission unit for transmitting the transmission data to a base station;
A reception result detection unit for detecting an ACK signal or a NACK signal transmitted from the base station with respect to the reception result of the transmission data;
For the transmission data transmitted at the time of the initial transmission of the transmission data, when the reception result detection unit detects neither an ACK signal nor a NACK signal, rate matching of the channel encoded data for transmitting the transmission data again A parameter setting unit that sets a rate matching parameter for initial transmission as the rate matching parameter used for
A mobile terminal device comprising:   The parameter setting unit, when neither an ACK signal nor a NACK signal is detected for any base station connected to the mobile terminal device via a radio link, the rate matching when transmitting the initial transmission data again. The mobile terminal apparatus according to claim 1, wherein a rate matching parameter for initial transmission is set as a parameter. A communication quality measuring unit for measuring communication quality between the mobile terminal device and the base station;
When no ACK signal is detected for any base station connected to the mobile terminal device through a radio link and the communication quality with the base station from which the NACK signal is detected satisfies a predetermined standard, the initial transmission The mobile terminal apparatus according to claim 1, wherein a rate matching parameter for initial transmission is set as the rate matching parameter for transmitting transmission data again. A method of transmitting data from a mobile terminal apparatus to a base station on an enhanced dedicated physical data channel for high-speed uplink packet access,
In accordance with a rate matching parameter determined according to whether transmission of transmission data is initial transmission or retransmission, the channel encoded data is subjected to rate matching processing by puncturing the channel encoded data of the transmission data,
Transmitting transmission data obtained by puncturing the encoded data to a base station;
Detecting an ACK signal or a NACK signal transmitted from the base station with respect to a reception result of the transmission data;
For the transmission data transmitted at the time of initial transmission of the transmission data, when neither an ACK signal nor a NACK signal is detected, in order to transmit the transmission data again, based on the rate matching parameter for initial transmission, A data transmission method characterized by performing the rate matching processing of channel encoded data.

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