JP2006109155A - Mobile communication equipment, radio communication method, and program for radio communication - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress power consumption as enhancing throughput of communication even when data are continuously transmitted. <P>SOLUTION: In mobile communication equipment 101, when a receiving part 102 receives data from a base station 100, a re-transmission request determination part 106 measures field intensity of received data, determines a communication state on the basis of the field intensity, updates reliability of the data on the basis of the communication state and when the reliability of the data does not exceed a predetermined threshold, transmits the number of times of re-transmission corresponding to the communication state to the base station 100 via a transmitting part 104. Then, the base station 100 re-transmits the data to the mobile communication terminal 101 for the number of times of re-transmissions. When the reliability of the data exceeds the predetermined threshold, a decoder part 103 decodes the re-transmitted data, combines it with the previous data, performs an error correction processing about the combined data and an error determination part 105 determines presence/absence of an error. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a mobile communication device, a wireless communication method, and a wireless communication program for communicating with another mobile communication device via a base station by a wireless communication method such as a CDMA method.

  In recent years, the importance of data communication in addition to voice communication is increasing as the mainstream of communication in wireless communication systems. This is because the demand for multimedia communication has increased rapidly, and the communication of e-mail on mobile phones has also increased the distribution of images and moving images. At this time, data communication is mainly performed by dividing the data into packets.

  The operation of the mobile communication device in conventional CDMA packet communication will be described. The mobile communication device receives data transmitted from the base station, and decodes the data received by the receiving unit. An error correction process is performed on the decoded data in the decoder unit. The error determination unit determines whether an error has occurred in the data. If there is no error in the data, the data is adopted as received data, and an ACK signal indicating completion of data reception is transmitted to the base station. Upon receiving the data reception completion determination from the mobile communication device, the base station transmits new data to the mobile communication device.

  If it is determined as an error as a result of the error determination process, the mobile communication device makes a data retransmission request to the base station by transmitting a NACK signal. Then, the data is decoded again with respect to the data retransmitted from the base station, and error correction processing is performed.

  Until there is no error in the above processing and the mobile communication device transmits an ACK signal, the base station continues to transmit data, and the mobile communication device repeats the data reception, decoding, error correction, and error determination processing. It will be.

  In the case of this configuration, if the communication state is poor and data containing a lot of noise is received, there is a high probability that an error will occur in the data, and data retransmission requests to the base station will frequently occur, and throughput will be reduced. The problem of deteriorating will arise. Furthermore, a series of processes of data decoding, error correction processing, and error determination processing are sequentially performed, leading to an increase in power consumption.

In order to solve such a problem, the field strength of the received data is sampled, the packet size and the number of continuous transmissions are determined based on the parameters that define the state of the radio channel obtained from the sampled data, and the transmission is performed. There is a conventional technique in which data is divided and stored in packets, and the packets are continuously transmitted for the number of times of continuous transmission (see, for example, Patent Document 1).
JP 2001-197144 A

  However, in the above-described prior art, although the field strength of the received data is sampled and the packet size and the number of continuous transmissions are controlled according to the state of the wireless line, all of the packets transmitted and received are transmitted. Although it is necessary to perform error correction processing and error determination processing for the communication, it is possible to improve communication throughput, but the number of error correction processing and error determination processing itself does not decrease, so in a mobile communication system There is a problem that the number of operating parts increases and it is difficult to reduce power consumption.

  Therefore, the present invention provides a mobile communication device and wireless communication capable of suppressing power consumption by reducing the number of error correction processes and error determination processes while improving communication throughput even when data is continuously transmitted. A method and a program for wireless communication are provided.

  In order to solve the above-described problem, the present invention determines a communication state every time data is received, requests the base station to retransmit the data based on the determined communication state, and the base station A configuration is adopted in which the same data transmitted a plurality of times is decoded and combined into one data, and error correction processing is performed on the combined data.

  According to the present invention, each time data is received, the communication state is determined each time, the base station is requested to retransmit the data based on the determined communication state, and the same data transmitted by the base station a plurality of times is received. Since the error correction process is performed by decoding and combining with 1 data, the number of error correction processes and error determination processes can be reduced even when the base station continuously transmits data based on the communication state. The power consumption can be suppressed while improving the communication throughput.

  Hereinafter, an embodiment of the present invention will be described.

  FIG. 1 shows a configuration of a mobile communication device according to the present embodiment of the present invention.

  In FIG. 1, mobile communication apparatus 101 according to the present embodiment includes receiving section 102, decoder section 103, transmitting section 104, error determining section 105, and retransmission request determining section 106.

  The receiving unit 102 receives data transmitted from the base station 100, demodulates the data modulated by the base station 100, and passes the data to the decoder unit 103.

  The decoder unit 103 receives and decodes the data from the base station 100 received by the receiving unit 102, combines the same data into one data, and performs error correction processing.

  The error determination unit 105 determines whether there is an error in the decoded and error-corrected data by CRC or the like.

  The transmission unit 104 transmits data and signals to the base station 100.

  The retransmission request determination unit 106 includes the retransmission number determination table 1061 illustrated in FIG. 2, measures the electric field strength of the data received by the reception unit 103, and refers to the retransmission number determination table 1061 to determine the received data The communication status rank is set based on the electric field strength, the number of retransmissions to the base station 100 is determined according to the communication status rank, and the data reliability is updated and the block error rate, which is the data error rate, is determined. The number of retransmissions to the base station 100 is determined.

  FIG. 2 is an example of the retransmission number determination table 1061 used when the retransmission request determination unit 106 determines the number of retransmissions based on the electric field strength.

  As shown in FIG. 2, in the retransmission count determination table 1061, four stages of communication states A to D, the number of retransmissions, the data reliability, and the block error rate are set correspondingly. Based on the electric field strength of the received data, retransmission request determination section 106 refers to retransmission number determination table 1061 and designates four-stage communication states A to D.

  For example, in rank A with the best communication state, as shown in FIG. 2, the number of retransmissions is “0”, the data reliability is “1”, and the block error rate, which is the data error rate, is “0” or measured. On the other hand, for rank D with the worst communication state, the number of retransmissions is set to “3”, the data reliability is set to “1/4”, the block error rate is set to “γ”, and the like. .

  Although details will be described later, the retransmission request determination unit 106 refers to the retransmission number determination table 1061 shown in FIG. 2 and determines the number of retransmissions based on the ranks A to D of the communication state and adds the data reliability. If there is an error in the error correction process, the number of retransmissions is determined again based on the block error rate that is the error rate of the data.

  Next, the operation will be described.

  FIG. 3 is a flowchart showing processing on data received by mobile communication apparatus 101 from base station 100.

  In mobile communication apparatus 101, when receiving section 102 receives data from base station 100, demodulation is performed (step S 11), and the demodulated received data is output to retransmission request determining section 106.

  The retransmission request determination unit 106 measures the electric field strength of the reception data received from the reception unit 102 (step S12), and refers to the retransmission number determination table 1061 shown in FIG. 2 based on the measured electric field strength of the reception data. Then, the communication state is determined (step S13). Further, based on the communication state, the reliability of the data is updated by adding to the data reliability when the same data as that data was previously received (step S14). The reliability of the updated data and a predetermined threshold value are updated. Are compared to determine whether the reliability of the updated data is a predetermined threshold, for example, 1 or more (step S15).

  Specifically, for example, in response to a request for the previous number of retransmissions from the mobile communication device 101, for example, the base station 100 is instructed to perform 3 retransmissions, and the normal state of the first received data is B. When the data reliability is 1/2 and the communication state of the second received data is C and the data reliability is reduced to 1/3, the data reliability is updated in step S15. The data reliability is 1/2 + 1/3 = 5/6.

  In this way, as shown in retransmission count determination table 1061, retransmission request determination section 106 holds a weighted value based on the communication state as the reliability of data, and the electric field strength of the data to be retransmitted has changed. In this case, the reliability of the data corresponding to the change in the communication state is always updated by adding the reliability of the data corresponding to the electric field strength to the data reliability when the same data as that data was previously received. Update. When the reliability of this data is equal to or higher than a predetermined threshold value (for example, 1 in the present embodiment), even if data for the number of retransmissions is not transmitted, It is assumed that data has been transmitted for the number of times of retransmission. As a result, in response to changes in the communication state, that is, if the communication state is improved, a smaller number of retransmissions than the initially specified number of retransmissions is sufficient, whereas if the communication state is deteriorated, the number of retransmissions is larger than the first specified number of retransmissions. By specifying the number of times again, the number of data retransmissions can be updated sequentially.

  If the retransmission request determination unit 106 determines that the reliability of the updated data is less than the threshold ("N" in step S15), the retransmission request determination unit 106 refers to the retransmission number determination table 1061 and sets the communication state measured this time. A NACK signal instructed to be retransmitted for the corresponding number of retransmissions is transmitted to the base station 100 via the transmission unit 104, and the base station 100 is allowed to continue data retransmission (step S20).

  On the other hand, when it is determined that the reliability of the updated data is equal to or higher than the threshold (step S15 “Y”), the retransmission request determination unit 106 instructs the decoder unit 103 to perform data synthesis and error correction processing. Output.

  As described above, in this embodiment, each time data is received, the communication state is determined and the data reliability is updated. Even if you are in a place with poor communication conditions, such as in a building, and you determine that the number of data retransmissions is three, for example, if you move from that place to a place with good communication conditions, such as outdoors, the reliability of the data corresponding to the communication condition Therefore, the decoder unit 103 is made to perform data composition and error correction processing even before the set number of retransmissions of data, for example, once before the number of retransmissions. On the other hand, when the mobile communication device 101 moves from a place with a good communication state to a bad place, the data corresponding to the communication state can be determined even if the number of retransmissions of the data is determined to be small, for example, once. If the reliability is lower, it is possible to cause the decoder unit 103 to perform data synthesis and error correction processing after retransmitting more times.

  Then, the decoder unit 103 decodes and synthesizes a plurality of identical data that have been transmitted so far, executes error correction processing on the synthesized data, and outputs the error-corrected data to the error determination unit 105 (Step S16). Note that the decoding and combining timing may be before or after the error correction processing instruction from the retransmission request determination unit 106 is input.

  When the combined and error-corrected data is input from the decoder unit 103, the error determination unit 105 performs error determination processing on the data and determines whether there is an error (step S17).

  As a result, when it is determined that there is an error (step S17 “N”), the error determination unit 105 issues an instruction to the retransmission request determination unit 106, and the retransmission request determination unit 106 determines the block error that is the error rate of the data. The rate is measured (step S19), the number of retransmissions is recalculated with reference to the retransmission number determination table 1061 shown in FIG. 2, and a NACK signal instructed to be retransmitted by the recalculated number of retransmissions via the transmitter 104. It transmits with respect to the base station 100 (step S20).

  For example, when the measured block error rate is smaller than α%, the retransmission request determination unit 106 refers to the retransmission number determination table 1061 shown in FIG. 2 and transmits a NACK signal instructed to add one more number of retransmissions. While transmitting to the base station 100, if the measured block error rate is larger than α% and smaller than β%, the number of retransmissions is instructed to be added twice, and when the measured block error rate is larger than γ%, A NACK signal instructed to add three more times is transmitted to base station 100.

  On the other hand, when it is determined that there is no error as a result of the error determination processing (step S17 “Y”), the error determination unit 105 issues an instruction to the retransmission request determination unit 106, and the retransmission request determination unit 106 An ACK signal is transmitted to the base station 100 via 104 to notify that the retransmitted data can be restored without error (step S18).

  As described above, in this mobile communication apparatus 101, even if the error correction processing result is incorrect, the received data can be reliably restored by adding the number of retransmissions according to the block error rate.

  Also, in this mobile communication apparatus 101, a plurality of identical data received after being retransmitted adaptively to the base station 100 according to the communication state are combined into 1, and error correction processing and error determination are performed on the combined data. Therefore, the number of error correction processes and error determination processes can be reduced while improving the communication throughput.

  Next, the data flow of the mobile communication device 101 according to the embodiment shown in FIG. 1 will be specifically described.

  FIG. 4 is a sequence diagram illustrating a transmission order of packet communication in the mobile communication device 101 according to the embodiment.

  In FIG. 4, it is assumed that the base station 100 transmits the packet 2 to the mobile communication device 101 after transmitting the packet 1.

  Here, when the communication state when the base station 100 transmits the packet 1 is bad, in the mobile communication device 101, the reception unit 102 receives and demodulates the packet 1 (step S11), and the retransmission request determination unit 106 Measures the field strength of packet 1 (step S12), determines the communication state to be “B” based on the measured field strength (step S13), and refers to the retransmission count judgment table 1061 shown in FIG. The reliability of the updated data is updated (step S14), and when the reliability of the updated data is less than a predetermined threshold ("N" in step S15), the retransmission number determination table 1061 is referred to and the number of retransmissions is set to NACK signal. To the base station 100 (step S20). At this time, the decoder unit 103 decodes the data of the packet 1 from the receiving unit 102 and stores it in its memory (not shown).

  Then, the base station 100 transmits the data of the packet 1 again as the packet 1 ′ after the transmission of the packet 2 in response to the instruction from the mobile communication device 101 for the number of retransmissions of 1 for the packet 1.

  In the mobile communication device 101, the reception unit 102 receives and demodulates the packet 1 ′ (step S11), the retransmission request determination unit 106 measures the electric field strength of the received packet 1 ′ (step S12), and the communication state (Step S13), and when the data reliability is updated (step S14) and the data reliability is equal to or higher than a predetermined threshold (step S15 “Y”), the retransmission request determination unit 106 determines the number of retransmissions. It is determined that the data that is sufficiently satisfied can be received, and the decoder unit 103 is instructed to decode and synthesize the received packet and perform error correction processing.

  Then, the decoder unit 103 combines the packet 1 stored in the memory (not shown) and the packet 1 ′ by addition or averaging, and performs error correction processing on the packet 1 + 1 ′ (step S16). ). Of course, a filtering process or the like may be performed at the time of the synthesis process.

  As described above, the packet 1 + 1 ′ combines the same data of the packet 1 and the packet 1 ′ to cancel random noise and the like, while the signal portion becomes obvious and the likelihood of error correction increases. As reliability improves.

  When the error determination unit 105 determines whether there is no error in the packet 1 combined with the packet 1 + 1 ′ by the decoder unit 103 and subjected to error correction processing (step S17), (Step S17 “Y”), an ACK signal is transmitted to the base station 100 (step S18), and the base station 100 is informed that data has been successfully received.

  FIG. 5 is a sequence diagram showing the transmission order of packet communication when the error determination unit 105 determines that there is an error.

  In FIG. 4, packet 1 and packet 1 ′ are combined to form packet 1 + 1 ′. In the error determination process in step S17 of FIG. 3, no error is detected and no error is detected, but the case shown in FIG. Will be described in the case where it is determined that there is an error in the error determination processing in step S17.

  In other words, in the case shown in FIG. 5, when packet 1 + 1 'is synthesized by combining packet 1 and packet 1 + 1', error correction processing is performed, and as a result of error determination processing, it is determined that there is an error (step S17 "N"). The determination unit 105 measures the block error rate of the combined packet 1 + 1 ′ (step S19), and outputs it to the measured block error rate retransmission request determination unit 106.

  The retransmission request determination unit 106 refers to the retransmission number determination table 1061 illustrated in FIG. 2 and resets the number of retransmissions based on the block error rate from the error determination unit 105, and transmits to the base station 100 via the transmission unit 104. Request retransmission.

  For example, if the measured block error rate is smaller than α%, retransmission request determination section 106 transmits a NACK signal to base station 100 so as to add the number of retransmissions once more, while the measured block error rate is α If it is larger than% and smaller than β%, the NACK signal is transmitted to the base station 100 so that the number of retransmissions is added two more times, and if the block error rate is larger than γ%, the number of retransmissions is further added three times. To do. As a result, even if the result of the error correction process is an error, the received data can be reliably restored by adding the number of retransmissions according to the block error rate.

  Then, the base station 100 retransmits the packet 1 ″ after retransmitting the packet 1 ′ in response to the retransmission request by the NACK signal again from the mobile communication device 101.

  In the mobile communication apparatus 101, the receiving unit 102 receives and demodulates the packet 1 ″ (step S11), passes the packet 1 ″ to the decoder unit 103, and measures the electric field strength of the received packet 1 ″ (step S11). In step S12, the communication state is determined (step S13), the data reliability is updated (step S14), and it is determined whether the data reliability is equal to or higher than the threshold (step S15). The unit 103 decodes and synthesizes the newly received packet 1 ″ with the packet 1 + 1 ′ received and synthesized so far to obtain a synthesized packet 1 + 1 ′ + 1 ″.

  When the retransmission request determination unit 106 determines that the reliability of the data is equal to or higher than the threshold (step S15 “Y”), the retransmission request determination unit 106 instructs the decoder unit 103 to perform error correction, and the decoder unit 103 The error correction process is performed on the packet 1 + 1 ′ + 1 ″ (step S16), and the error determination unit 105 performs the error determination process (step S17).

  As a result, if it is determined that there is no error in this data (step S17 “Y”), retransmission request determination section 106 transmits an ACK signal to base station 100 via transmission section 104, and packet 1 is Notify that you have received.

  On the other hand, when it is determined that there is an error in this data (step S17 “N”), the retransmission request determination unit 106 again measures the block error rate (step S20), and the retransmission shown in FIG. The number of retransmissions is determined based on the block error rate with reference to the number of times determination table 1061, and a NACK signal is transmitted to the base station 100 via the transmission unit 104 to notify the new number of retransmissions.

  Therefore, according to the present embodiment, retransmission request determination section 106 sets the number of retransmissions to base station 100 based on the communication state, and decoder section 103 decodes a plurality of identical data retransmitted from base station 100. The number of error correction processes and error determination processes in the mobile communication device 101 even when the base station 100 continuously transmits the same data. The power consumption can be suppressed while improving the communication throughput.

  In particular, in the present embodiment, as shown in the retransmission number determination table 1061 in FIG. 2, the weighted number of retransmissions and the data reliability are set according to the communication state, and the data is received. In addition, the electric field strength of the received data is measured, the data reliability is updated, the number of retransmissions according to the total is instructed to the base station 100, and the total data reliability exceeds a predetermined threshold value. In this case, the decoder unit 103 synthesizes the same data received so far and performs error correction as one data, so that not only can the number of error correction processes be reduced, but also the mobile communication device 101 can perform communication. Even when moving from a bad state to a good state, a decrease in data throughput can be prevented.

  That is, the mobile communication device 101 is often used while being moved, and it is expected that the communication state is constantly changing. At this time, when the reception state of the first data is poor and the number of retransmissions is set to a large number, in the conventional device, even if the mobile communication device 101 moves and the communication state is improved, the communication state is poor. Data is transmitted and received a plurality of times according to the determined number of retransmissions, leading to a decrease in data throughput. On the other hand, in the present embodiment, by measuring the electric field strength of the data received by the retransmission request determination unit 106 every time data is received, it responds to changes in the communication state as needed. Even if the field strength of the received data is low and the number of retransmissions is set high, if the field strength of the second received data is high, the reliability of the data becomes higher than the first time. The station 100 is notified.

  Further, when the mobile communication device 101 moves from a good communication state to a bad communication state, for example, even if the electric field strength of the first received data is high and the number of retransmissions is set low, the electric field strength of the second received data is Is low, the reliability of the data is lower than the first time, so it is possible to reset the number of retransmissions and notify the base station 100, and when the error is determined after the error correction process, the number of errors is determined. Not only can the communication throughput be improved, but also the number of error correction processing and error determination processing can be reduced, and power consumption can be reduced.

  In the mobile communication device 101 according to the present embodiment, when the reliability of the updated data is less than the threshold, the retransmission request determination unit 106 refers to the retransmission number determination table 1061 and sets the communication state measured this time. The base station 100 is requested to retransmit the data a corresponding number of times, but the present invention is not limited to this, and the reliability of the updated data is less than the threshold value regardless of the communication state. The base station 100 may always be requested for the number of retransmissions. If the reliability of the updated data is less than the threshold value, for example, according to the reliability of the updated data, If the reliability is 1/3 + 1/4 = 7/12, referring to the retransmission count determination table 1061, 1/2 <7/12 <1, so it is determined that the number of retransmissions is 1 or the like, and update is performed. Data Course it may be requested by the base station 100 to resend the number of retransmissions in accordance with the time. Even in this case, in this embodiment, every time data is received, the communication state is determined and the reliability of the data is updated and compared with the threshold value. Therefore, the reliability of the updated data is the threshold value. If the number is less than the threshold value, a retransmission request is always transmitted to the base station 100 until the threshold value is exceeded, so that the same effect as instructing retransmission for the number of retransmissions corresponding to the communication state can be obtained.

  This also applies to the case where the retransmission request determination unit 106 determines that there is an error and determines the number of retransmissions according to the block error rate and requests the base station 100 to perform retransmission. In this case, the base station 100 may be requested to request the number of retransmissions once, regardless of the block error rate. In this way, the block error rate measurement process in S19 can be omitted, and the number of operating parts is reduced in this respect as well, so that power consumption can be reduced.

  Further, in the present embodiment, as shown in FIG. 1, the configuration of the mobile communication device 101 is shown in hardware by a block diagram, but the present invention is not limited to this, and the mobile communication device is not limited thereto. 101 is executed by a general-purpose computer such as a PC having a CPU and a hard disk storing a wireless communication program for executing the CPU as described above, or a storage device such as a memory as software. Is of course good. In this case, the wireless communication program for performing the function as the mobile communication device described above is recorded on a recording medium such as a CD, and is read from the recording medium and installed in a storage device in the computer. It is downloaded from a server or the like via a network such as the Internet and stored in a storage device. In this way, even a general-purpose computer such as a PC may execute the wireless communication method shown in FIG. 3 by executing the program for performing the function as the mobile communication device described above. .

  According to the mobile communication device, wireless communication method, and wireless communication program of the present invention, the number of error correction processing and error determination processing can be reduced while improving communication throughput even when data is continuously transmitted. This has an advantageous effect that power consumption can be suppressed, and can contribute to reduction of power consumption of the mobile communication device.

The block diagram which shows the structure of the radio | wireless communications system of embodiment of this invention The figure which shows an example of the retransmission count determination table of the retransmission request determination part Flowchart showing processing for data received by mobile communication device from base station Sequence diagram showing transmission order of packet communication in mobile communication device of embodiment The sequence diagram which shows the transmission order of packet communication when it determines with an error in the error determination part of embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Base station 101 Mobile communication apparatus 102 Reception part 103 Decoder part 104 Transmission part 105 Error determination part 106 Retransmission request determination part

Claims (6)

A mobile communication device that performs data communication with another mobile communication device via a base station,
A retransmission request determination unit that determines a communication state each time data is received, and requests the base station to retransmit the data based on the determined communication state;
A decoder unit that decodes the same data transmitted by the base station a plurality of times and combines it into one data, and performs error correction processing on the combined data;
A mobile communication device comprising: When the retransmission request determination unit requests the base station to retransmit data based on the determined communication state, the retransmission request determination unit requests the base station to retransmit the data for the number of retransmissions according to the determined communication state. To
The mobile communication apparatus according to claim 1. The retransmission request determination unit, when determining the communication state every time data is received, adds the data reliability corresponding to the determined communication state to the data reliability when the same data as that data was previously received. If the updated data reliability does not exceed a predetermined threshold, the base station is requested to retransmit the data, while the updated data reliability exceeds a predetermined threshold, Causing the decoder unit to perform error correction processing of the combined data;
The mobile communication device according to claim 1 or 2, characterized in that Further, an error determination unit that determines whether or not there is an error in the composite data that has been subjected to error correction processing by the decoder unit,
If it is determined that there is an error in the combined data that has been subjected to error correction processing by the error determination unit, the retransmission request determination unit retransmits the data for the number of retransmissions corresponding to the error rate of the data. Request to the base station;
The mobile communication device according to any one of claims 1 to 3, wherein the mobile communication device is characterized in that: A wireless communication method of a mobile communication device that performs data communication with another mobile communication device via a base station,
Each time data is received, the communication state is determined, and the base station is requested to retransmit the data based on the determined communication state, and the same data transmitted by the base station multiple times is decoded and 1 Combine the data and perform error correction on the combined data.
A wireless communication method. A wireless communication program for a mobile communication device that performs data communication with another mobile communication device via a base station,
Each time data is received, the communication state is determined, and the base station is requested to retransmit the data based on the determined communication state, and the same data transmitted by the base station multiple times is decoded and 1 Combine the data and perform error correction on the combined data.
A program for wireless communication that causes a mobile communication device to execute the above.

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