JP3356146B2 - Communication terminal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication terminal, and more particularly, to a communication terminal that performs retransmission control when an error in received data is detected.

[0002]

2. Description of the Related Art Mobile phones and personal handy-phone systems (hereinafter abbreviated as PHS) as wireless mobile terminals have been reduced in size and weight and provided with more functions. Opportunities to perform not only voice calls but also data communications such as transmission and reception of the Internet or e-mail are increasing. In a mobile communication environment,
Compared to wired, multi-path fading caused by geographical conditions, city noise generated by various electronic devices, interference between radio waves in the same frequency band, etc. deteriorate the transmitted and received signals, resulting in errors in received data The likelihood of doing so is significantly higher. In particular, in the case of data communication, an error in received data cannot be allowed.

[0003] Even if such signal degradation occurs, error correction is performed to enable data communication. This error correction is performed, for example, by performing a Cyclic Redundancy Check (hereinafter abbreviated as CRC) coding for error detection on the transmission side, and a BCH (Bose-Chaudhuri-code) as a block code having higher error correction capability. Hocquengh
em) After encoding, it is transmitted after interleaving. On the receiving side, after deinterleaving, error correction is performed by BCH decoding, and then a CRC check is performed to detect errors. If the error correction code of the BCH code and the error detection code of the CRC code are added, the throughput of the data communication is reduced accordingly, so that it is necessary to achieve both the throughput and the reliability in the communication system.

In packet communication performed using a mobile phone, whether or not to perform forward error correction (hereinafter, abbreviated as FEC) is determined according to the reception level at the start of the packet communication. Communication is performed in a determined data format. When the reception level at the start of packet communication is low, that is, when the mobile communication environment is poor, communication is generally performed on the premise of FEC in a data format to which a redundant error correction code capable of correcting one bit error is added. On the other hand, if the reception level at the start of packet communication is high, that is, if the mobile communication environment is good, communication that does not assume FEC in a data format that does not add redundant error correction codes is performed.
In this case, if even a single bit error is detected on the receiving side, retransmission control is performed without correcting the data error, and an attempt is made to re-receive error-free data. FEC
Is not performed in the mobile communication environment as described above, so that the probability of occurrence of an error is low. However, once an error is detected, a backward process called retransmission control of received data occurs, which causes a decrease in data transmission throughput. Below, FE
Data communication without C will be described.

FIG. 8 shows an example of retransmission control timing in packet communication by a conventional portable telephone. FIG. 2A shows an uplink user packet channel (User P) transmitted from a mobile phone to a base station.
acket CHannel: Abbreviated below as UPCH. ) Shows data. FIG. 2B shows downlink UPCH data transmitted from the base station to the mobile phone. Figure (c)
Shows the timing of the reception completion signal generated when the reception of the uplink UPCH data is completed in the mobile phone. FIG. 3D shows the timing of the CRC calculation process performed when the mobile phone receives downlink UPCH data. FIG. 9E shows the occurrence of a CRC error detected as a result of the CRC calculation process.

As shown in FIG. 1B, _first to _N-th unit data 10 ₁ to 10 _N are transmitted from the base station to the downlink UPCH.
Sent as data. The first to N-th unit data 10 ₁ to 10 _N are packet frame data 11 in which predetermined frame data is packetized by the base station. Mobile phone, CRC calculation process 12 ₁ to 12 _N is performed each time it receives the unit data 10 ₁ to 10 _N of the first to N.
Each CRC calculation process 12 ₁ to 12 _N, occurrence of reception completion signal 13 ₁ to 13 _N in synchronization with CRC error indicating the completion of reception of each unit data is detected. here,
Second unit data 10 ₂ only, assuming that the data error has occurred, when the CRC error is detected in the CRC calculation process 12 _2, in synchronization with the reception completion signal 13 _2,
CRC error 1 indicating that a CRC error has occurred
4 stands up.

When an error occurs in the received unit data, a retransmission request 15 for the second unit data is sent to the portable telephone in response to the CRC error 14 indicating the occurrence of the error in the second unit data. UPCH from
It is transmitted to the base station as data. The second unit data 16 is transmitted again as downlink UPCH data from the base station receiving this. In the mobile phone, the received second unit data 16 is subjected to a CRC again.
When the calculation processing 17 is performed and no error is detected,
The transmission side frame data is reproduced.

As described above, if even a single bit error occurs in packet communication by a portable telephone that does not perform FEC, the data throughput decreases due to the retransmission process of retransmission control. It is desirable that the error can be corrected without adding a new code.

For example, Japanese Unexamined Patent Publication No. Hei.
The 1-bit error correction circuit based on the RC operation includes a 1-bit error detection circuit that decodes a syndrome using a predetermined cyclic circuit, detects a 1-bit error, and performs an exclusive OR operation with the reproduced main signal to obtain correction data. An error correction technique is disclosed. If this is applied to a mobile phone, the received downlink U
When even one bit error occurs in the PCH data,
It is possible to correct this and eliminate the need for retransmission control.

[0010]

However, in a communication terminal to which the technique disclosed in Japanese Patent Application Laid-Open No. Hei 5-227041 is applied, a cyclic circuit is used. Therefore, as the number of bits of the data to be inspected increases, the CRC error detection processing is performed. It takes time. In particular, in packet communication using a mobile phone as a communication terminal, the throughput of data communication is improved until redundant error correction codes are not added. Nevertheless, if the CRC error detection processing takes time, it is not possible to improve the throughput of data communication. Furthermore, when performing a CRC error detection process using a predetermined algorithm, the development TAT becomes longer due to its development and verification. Therefore, it is desirable to simplify the configuration as much as possible.

Accordingly, an object of the present invention is to simplify the configuration and perform high-speed data error correction irrespective of the number of bits of received data even when performing data communication that does not assume FEC. An object of the present invention is to provide a communication terminal for improving throughput.

[0012]

In the invention SUMMARY OF THE INVENTION Claim 1, wherein a first error detecting means for detecting based on an error of the received data added in advance an error correction code (b) the error correction code, ( B) Each bit of the received data is
Reception that generates bit-inverted data inverted by one bit
Bit inversion means for the number of data bits;
Each bit inversion data is provided corresponding to the bit inversion means.
Bit error of the number of received data bits that
And (d) these bit-reversed data.
Error of bit-reversed data detected by data error detection means
Whether there is only one bit-reversed data that has not been
And (e) first error detecting means.
Therefore, if no error is detected, select the received data
The error is detected by the first error detection means,
No bit-reversed data error detected by stage
When it is determined that only one bit-reversed data exists
Data selecting means for selecting the bit-inverted data;
(F) To the data selected by this data selection means
A reception processing means for performing predetermined reception processing on the communication terminal;
To be prepared.

[0013]

[0014]

[0015] That is, in the first aspect of the present invention, the first first error detecting means, for detecting, based an error in received data in advance the error correction code is added to the error correction code. Further, bit inversion data in which each bit of the reception data is inverted by one bit is generated by the bit inversion means by the number of bits of the reception data, and provided by the bit inversion data error detection means provided corresponding to these bit inversion means. , An error of each bit-reversed data is detected. Further, the discriminating means discriminates whether or not there is only one bit-reversed data for which no error of the bit-reversed data is detected by the bit-reversed data error detecting means. Then, when no error is detected by the first error detecting means, the received data is selected as the data to be received, and the error is detected by the first error detecting means. When it is determined that only one bit inversion data that has not been detected exists, this bit inversion data is selected.

According to the second aspect of the present invention, (a) first error detecting means for detecting an error of received data to which an error correction code is added in advance based on the error correction code;
(B) Invert each bit of the received data by one bit
Received data bit that generates inverted bit inverted data
Bit inversion means for several minutes, and (c) these bit inversion means
Detects errors in bit-reversed data
Bit-reversed data error detection for the number of received data bits
Output means, and (d) these bit-reversed data error detection means.
For which no bit-reversed data error was detected
To determine whether only one bit-reversed data exists.
An error is detected by another means and (e) the first error detection means.
Error of the bit-reversed data output by the discriminating means
0 or 2 or more bit inversion data for which no
If it exists, it is deemed impossible to correct the error.
The communication terminal is provided with retransmission request means for requesting retransmission to a data transmission source .

That is, according to the second aspect of the present invention, an error of the received data to which the error correction code is added in advance by the first error detection means is detected based on the error correction code . In addition, each bit of the received data is
The bit inversion data inverted only by
Each bit is generated by bit inversion means for several minutes.
Bit inversion data error is provided corresponding to the bit inversion means.
Error detection means for detecting an error in each bit-inverted data.
You. Furthermore, these bit inversion data are determined by the determination means.
Data error detection means detects bit-reversed data errors.
Whether there is only one bit-reversed data that was not output
It is determined whether or not. And, as the data to be received,
An error is detected by the first error detecting means, and
No error in bit-reversed data is detected by the discriminating means.
If there are 0 or more bit-reversed data
Error correction cannot be performed,
Requested retransmission from sender. This
Data without adding a new redundant error correction code.
Data communication throughput can be improved
Data reliability can be avoided.
You.

[0018]

[0019]

According to the third aspect of the present invention, the first aspect or the first aspect
3. The communication terminal according to claim 2 , wherein the error correction code is a cyclic redundancy check code.

That is, according to the third aspect of the present invention, the data error is detected by using the cyclic redundancy check code used in the existing data communication, so that the conventional error detection circuit can be efficiently applied. Become possible, development TAT
Can be shortened.

[0022] In the invention of claim 4, claims 1
Item 4. The communication terminal according to any one of Items 3 , wherein the received data is received in data communication without performing forward error correction.

In other words, the invention according to claim 4 can be applied to data communication without forward error correction performed by a radio wave environment at the start of reception in packet communication in a cellular phone, for example, and extremely efficient data communication is possible. Communication is enabled, and the load on the mobile communication network can be greatly reduced.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments.

FIG. 1 shows an outline of the configuration of a portable telephone as a communication terminal in one embodiment of the present invention. The mobile phone includes a wireless unit 20 for transmitting and receiving a communication signal to and from a base station (not shown) via a wireless line, a transmitting and receiving unit 21 for performing data communication processing of a signal transmitted and received by the wireless unit 20, and a wireless unit 20. And a control unit 22 for controlling communication with a base station (not shown).

The portable telephone according to the present embodiment is capable of performing packet communication in a predetermined format, and determines whether or not to perform FEC according to the reception level at the start of the communication. Communication is performed in a predetermined data format depending on whether or not FEC is performed. Further, the mobile phone according to the present embodiment can correct a 1-bit error at high speed without adding a redundant error correction code even at the time of packet communication not premised on FEC, thereby improving the throughput of data communication. It is characterized by improvement.

The transmitting / receiving section 2 of the mobile phone in the present embodiment
1 includes a channel coding / decoding (COderand DECorder: hereinafter abbreviated as CODEC) unit 23. The channel CODEC unit 23 performs data processing at the layer 1 level which is the lowest layer level in a communication protocol in data transmission.

The channel CODEC 23 is a decoder
4, a 1-bit error correction unit 25, a two-input one-output selector 26, and an encoder 27. Decoder 2
4 is a downlink UP of a predetermined format from received data 28 as unit data from a base station (not shown).
The CH data is reassembled as the decoding result UPCH data, and the UPCH data 29 is extracted therefrom.

FIG. 2 shows an example of the configuration of the decoded result UPCH data processed by the decoder 24 and the data format of the UPCH data.
FIG. 9A shows an example of the configuration of the decoded result UPCH data. FIG. 2B shows an example of the configuration of the UPCH data 29. The decoding result UPCH data 30 is 28
An R bit 31 having a 0-bit configuration and a 4-bit configuration;
P bit 32 of 2 bits configuration and U bit of 112 bits configuration
PCH bit 33 and SW bit 34 of 20 bits configuration
, An 8-bit CC bit 35, a 112-bit UPCH bit 36, and a 22-bit E bit 37. The R bit 31 has a role of a guard bit between the unit data in the up direction and a specific pattern. A specific pattern is arranged as the P bit 32 as a preamble bit. SW bit 34 is
This is a synchronization word having a predetermined pattern, and determines the reception timing of unit data. CC bit 35
Specifies the scrambling pattern and specifies the type of scrambling applied on the transmitting side. The E bit 37 is an echo bit, and is an area in which data transmitted in the upstream direction is directly transmitted in the downstream direction.

From the decoded result UPCH data 30 having such a configuration, the decoder 24 converts the UPCH data shown in FIG.
From CH bits 33 and 36, UP with user data
The CH data 29 is taken out. UPCH data 29 is 2
It has a 24-bit configuration and includes user data 38 having a 208-bit configuration and CCR bits 39 having a 16-bit configuration.

Returning to FIG. 1, the description will be continued. The decoder 24 for extracting the UPCH data 29 as shown in FIG. 2 further includes a reception completion signal 40 for notifying the reception completion of the unit data.
And a CRC error detection signal 41 for notifying the presence or absence of a CRC error detection as a result of checking the CRC bit 39 added to the extracted UPCH data 29. UPC
The H data 29 includes a 1-bit error correction unit 25, a 2-input 1
It is supplied to the output selector 26. Reception complete signal 40
Is supplied to the control unit 22 and the 1-bit error correction unit 25. The CRC error detection signal 41 is transmitted to the control unit 22 and 2
It is supplied to the input 1 output selector 26.

The 1-bit error correction section 25 synchronizes with the reception completion signal 40 and outputs a CR
When the occurrence of the C error is detected, the UPCH data 29
Generates an error correction enable / disable signal 42 indicating whether 1-bit error correction is possible and corrected data 43 after 1-bit error correction. The error correction enable / disable signal 42 is supplied to the control unit 22 and the two-input one-output selector 26. Correction data 43
Are supplied to a two-input one-output selector 26.

When a CRC error of the UPCH data extracted by the decoder 24 is not detected from the CRC error detection signal 41 and the error correction enable / disable signal 42, the two-input one-output selector 26 outputs the UPCH supplied from the decoder 24. Select data 29 to download downlink UPCH data 4
4 is output to the control unit 22. When a CRC error of the extracted UPCH data is detected by the decoder 24 and the error correction enable / disable signal 42 indicates that error correction is possible, the correction data 43 supplied from the 1-bit error correction unit 25 is selected and the downstream UPCH data is selected. Output to the control unit 22 as 44. Further, when a CRC error of the extracted UPCH data is detected by the decoder 24 and the error correction enable / disable signal 42 indicates that error correction cannot be performed, the predetermined 224-bit configuration data is selected. , The incoming UPCH
The data 44 is invalidated and retransmitted to the base station.

When transmitting the uplink UPCH data 45 from the mobile phone in this embodiment to the base station (not shown), the encoder 27 performs a predetermined encoding process and supplies it to the radio unit 20 as transmission data 46. , A transmission completion signal 47 to the control unit 22.

FIG. 3 shows a main part of the configuration of the 1-bit error correction section 25 in the present embodiment. The 1-bit error correction unit 25 in the present embodiment is configured to receive first to 22nd UPCH data 29 each having a 224 bit configuration.
It includes a 4-bit inversion circuit 50 ₁ to 50 _224, and a CRC circuit 51 _{1-51 224} first to 224 that are connected in correspondence with the bit inversion circuit 50 ₁ to 50 ₂₂₄ of these first to 224 ing. The first to 224th bit inversion circuits 50 ₁ to 50 ₁
50 ₂₂₄ generates the first to 224 bit inverted data 52 _{1-52 224} only first to 224-th bit of the UPCH data 29 for each 224 bit configuration bit-inverted, first to 224 each CRC circuits 51 _{1 to} 5
Output to 1 ₂₂₄ . For example, the second bit inversion circuit 50 ₂ generates _second bit inversion data 52 ₂ by inverting only the second bit of the 224-bit UPCH data 29, and outputs the second bit inversion data 52 ₂ to the second CRC circuit 51 ₂ . Output to

Further, the 1-bit error correction section 25 has
An input 1 output selector 53 and a correction possibility determination circuit 54 are provided. First to 224th bit-reversed data 52 ₁
To ₂₂₄ are 224 input and 1 output selectors 53, respectively.
Is also supplied.

The first to 224th CRC circuits 51 _{1 to} 51
_Reference numeral ₂₂₄ checks the CRC bits shown in FIG. 2B for the data in which only one specific bit is inverted. Then, the detection result of whether or not a CRC error has occurred is
First to 224th CRC error presence / absence information 55 _{1 to} 55 ₂₂₄
Is supplied to the correction possibility determination circuit 54. The correction possibility determination circuit 54 synchronizes with the reception completion signal 40 and
From the CRC error presence / absence information 55 _{1 to} 55 _{224 of the} 24
If only one C error does not occur, a selection control signal 56 for selecting the bit-inverted data is generated to generate 2 bits.
While selecting and controlling the 24-input / 1-output selector 53,
An error correction enable / disable signal 42 indicating that error correction is possible is output. In addition, the correction possibility determination circuit 54 includes a first to a 224th CRC.
From the error presence / absence information 55 _{1 to} 55 ₂₂₄ , if there is 0 or more than one where no CRC error has occurred, a selection control signal 56 is generated to select predetermined bit-inverted data, and error correction is disabled. Is output.

The 224 input / output selector 53 includes first to first
Only the bit inverted data of alternatively selected 224 bits constituted by the selection control signal 56 from the bit inverted data 52 _{1-52 224} of the first 224, and outputs it as correction data 43.

In the portable telephone having such a configuration, the decoder 24 extracts the downlink UPCH data 29 received from the base station (not shown), and extracts the downlink UPCH data 29 from the CRC bits assigned in advance by the transmitting base station. The occurrence of a CRC error is detected. UPCH data 2
9, the 1-bit error correction unit 25 detects the presence or absence of a CRC error of bit-inverted data obtained by inverting 1 bit different from each other by the number of bits of the UPCH data, and the decoder 24 detects the CRC error. If not, the UPCH data 29 is decoded by the decoder 24 and the one-bit error correction unit 25 outputs only one CRC error.
When there is any data in which no C error has occurred, the bit-inverted data having no error is selected as the downlink UPCH data 44. As a result, the received UPC
Even if an error of only one bit occurs in H data, error correction can be performed with a very high-speed and simple configuration, and a retransmission request to the base station can be omitted, thereby improving the data communication throughput.

The control unit 22 has a central processing unit (CPU) (not shown), and based on a control program stored in a predetermined storage device, unit data for which error correction is impossible. Can be executed.

FIG. 4 shows an outline of the processing contents of the retransmission control by the control unit 22 in this embodiment. The control unit 22 monitors the reception of the reception completion signal 40 generated by the decoder 24 (step S60: N), and when detecting this (step S60: Y), furthermore, the CRC error detection signal generated by the decoder 24. With reference to 41, it is determined whether or not a CRC error has occurred in the received UPCH data 29 (step S61).
When it is determined that a CRC error has occurred (step S61: Y), it is determined whether error correction of the UPCH data 29 is possible with reference to the error correction enable / disable signal 42 generated by the 1-bit error correction unit 25. (Step S6)
2). When it is determined from the error correction enable / disable signal 42 that the error correction of the UPCH data 29 is not possible (step S62: N), the base station (not shown) is requested to retransmit the unit data in which the error has occurred (step S62). S63).

In step S61, the CRC error detection signal 4
If no CRC error has occurred in the UPCH data 29 due to 1 or if it is determined in step S62 that the error correction of the UPCH data 29 is possible by the error correction enable / disable signal 42, no retransmission request is made (end). .

FIG. 5 shows an outline of the retransmission request processing by the control unit 22 in this embodiment. In step S63 in FIG. 4, when a retransmission request for unit data that cannot be corrected is made to a base station (not shown), first, uplink UPCH data 45 indicating a retransmission request is generated (step S70). The data is transmitted (step S71). After that, the control unit 22 sends the transmission completion signal 47
Is received (step S72: N). Encoder 27
Performs a predetermined encoding process and transmits the transmission data 46 to the wireless unit 20. At this time, since the encoder 27 transmits the transmission completion signal 47 to the control unit 22, the control unit 22 receives the transmission completion signal 47 (Step S
72: Y), a series of retransmission request processing ends (END).

Next, the flow of packet communication by the portable telephone according to the present embodiment will be specifically described.

FIG. 6 shows an example of the timing of packet communication by the portable telephone in this embodiment. FIG. 3A shows uplink UPCH data transmitted from a mobile phone to a base station. FIG.
Indicates downlink UPCH data transmitted from the base station to the mobile phone. FIG. 11C shows the timing of the reception completion signal generated when the reception of the uplink UPCH data is completed in the mobile phone. FIG. 3D shows a CR performed by a mobile phone when receiving downlink UPCH data.
The timing of the C calculation process is shown. (E) of FIG.
This shows the occurrence of a CRC error detected as a result of the calculation processing.
FIG. 11F shows the 1-bit error correction unit 2 in the present embodiment.
5 shows the timing of the one-bit error correction process performed in Step 5.

As shown in FIG. 6B, _first to _Nth unit data 80 ₁ to 80 _N are transmitted from the base station to the downlink UPCH.
Sent as data. The first to N-th unit data 80 ₁ to 80 _N are packet frame data 81 in which predetermined frame data is packetized by the base station. The mobile phone performs the CRC calculation processing 82 _{1 to} 82 _N every time the _first to _N-th unit data 80 ₁ to 80 _N are received. Each C
When a CRC error is detected in the RC calculation processes 82 _{1 to} 82 _N , the CRC error is notified in synchronization with the reception completion signals 83 _{1 to} 83 _N indicating the completion of reception of each unit data.
Here, the second unit data ₈₀₂ only, assuming that the data error has occurred, CRC calculation process 82 ₂
, A CRC error 84 is detected. If the detected CRC error only a specific one bit of UPCH data received in synchronization with the reception completion signal 83 _2, error correction processing 85 in 1-bit error correction unit 25 is performed.

As described above, in the 1-bit error correction section 25, for error correction of only 1 bit, the error can be corrected at high speed without adding a new error correction code, and retransmission to the base station is performed. Since frame data can be reproduced without making a request, the throughput of data communication can be improved as compared with the related art.

Modification

In the portable telephone as a communication terminal in this embodiment, the 1-bit error correction unit 25 generates bit-inverted data in parallel by the bit length of the UPCH data 29 and corrects the error. However, the present invention is not limited to this. For example, the 1-bit error correction unit 25 and the 2-input / 1-output selector 26 may be omitted, and the direct control unit 25 may perform error correction by software processing. In this case, although the error correction processing is performed at a low speed, each step is greatly simplified, so that its design and verification are also simplified, and the development TAT can be greatly reduced.

That is, in the mobile phone according to the present modification, the UPCH data extracted by the decoder is directly supplied to the control unit. This control unit is capable of determining whether or not error correction is possible and performing error correction.

FIG. 7 shows an outline of a process of judging whether or not error correction can be performed by the control unit according to this modification. Here, it is assumed that n-bit UPCH data is handled and the least significant bit is the first bit. That is, the control unit in the present modification first sets the variable i to “0” (Step S90). Next, the UPC extracted from the decoder
Invert the i-th bit of the H data (step S91), and
An RC calculation is performed (step S92), and it is determined whether a CRC error has occurred (step S93). CRC
When it is determined that an error has occurred (step S9)
3: Y), “1” is added to the variable i (step S9)
4) Then, the value of the variable i after the addition is the error correction target UP
It is determined whether or not the bit length is longer than the bit length n of the CH data (step S95). When it is determined that the value of the variable i is not greater than the bit length n (step S95: N), the process returns to step S91 to continue detecting the CRC error.

When it is determined in step S95 that the value of the variable i is larger than the bit length n (step S95:
Y), it is determined that error correction is impossible, and downlink UPCH data is generated (step S96).

When the occurrence of a CRC error is not detected in step S93 (step S93: N), downlink UPCH data is generated as error-correctable (step S97).

The control unit that has determined whether or not the error can be corrected in accordance with the CRC error detection signal from the decoder.
When no RC error occurs, predetermined reception processing is performed using the UPCH data extracted by the decoder as downlink UPCH data. The occurrence of a CRC error is detected by the CRC error detection signal from the decoder, and when it is determined in step S96 of FIG. 7 that the error can be corrected, the bit-inverted data of the i-th bit in which the CRC error has occurred is downloaded downward.
A predetermined receiving process is performed as the CH data. Otherwise, retransmission control is performed as described with reference to FIGS.

In this embodiment and the modification, the communication terminal is described as a mobile phone, but the present invention is not limited to this. For example, a personal digital assistant (Person
al Digital Assistants: PDA)
In addition, the present invention can be applied to a communication terminal in a wired communication system.

[0057]

As described above, according to the first aspect of the present invention, each bit of the received data is inverted without adding a new error correction code.
Data generation and data error detection in parallel.
So if the number of bits in the received data is
Can detect and correct data errors at high speed.
Wear. Also, when a 1-bit data error occurs,
You don't have to make a retransmission request to the base station.
To increase the data communication throughput compared to the past.
Can be

[0058]

[0059]

According to the second aspect of the present invention, when an error is detected by the first error detecting means and the error cannot be corrected, a request is made to the source of the received data for retransmission. In addition, the throughput of data communication can be improved without adding a new redundant error correction code, and a decrease in the reliability of data communication can be avoided.

According to the third aspect of the present invention, a data error is detected by using a cyclic redundancy check code used in existing data communication, so that a conventional error detection circuit can be efficiently applied. It becomes possible to develop TA
T can be shortened.

Further, according to the fourth aspect of the present invention,
For example, it can be applied to data communication that does not perform forward error correction performed by the radio wave environment at the start of reception in packet communication in mobile phones, enabling extremely efficient data communication and greatly increasing the load on the mobile communication network. Can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an outline of a configuration of a mobile phone as a communication terminal according to an embodiment.

FIG. 2 is an explanatory diagram illustrating an outline of a configuration of data received by packet communication in the present embodiment.

FIG. 3 is a block diagram illustrating a main configuration of a 1-bit error correction unit according to the embodiment.

FIG. 4 is a flowchart illustrating an outline of a retransmission control process according to the embodiment.

FIG. 5 is a flowchart showing an outline of a retransmission request process in the embodiment.

FIG. 6 is a timing chart showing an example of the timing of packet communication by the conventional mobile phone in the embodiment.

FIG. 7 is a flowchart showing an outline of a process of determining whether or not error correction is possible in the present modified example.

FIG. 8 is a timing chart showing an example of retransmission control timing in packet communication by a conventional mobile phone.

[Explanation of symbols]

 Reference Signs List 20 radio section 21 transmission / reception section 22 control section 23 channel CODEC section 24 decoder 25 1-bit error correction section 26 2-input 1-output selector 27 encoder 28 reception data 29 UPCH data 40 reception completion signal 41 CRC error detection signal 42 error correction enable / disable signal 43 Correction data 44 Downlink UPCH data 45 Uplink UPCH data 46 Transmission data

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04L 1/00 H03M 13/00

Claims (4)

(57) [Claims] A first error detecting means for detecting an error of received data to which an error correction code is added in advance based on the error correction code; and a bit inversion in which each bit of the received data is inverted by one bit. Bit inversion means for the number of bits of the received data for generating data; bit inversion data error detection for the number of bits of the reception data provided corresponding to these bit inversion means for detecting an error of each bit inversion data Means for judging whether or not there is only one bit-inverted data for which no error of the bit-inverted data is detected by the bit-inverted data error detecting means; If no error is detected, the received data is selected and an error is detected by the first error detection means, Data selecting means for selecting the bit-inverted data when it is determined by the stage that there is only one bit-inverted data in which no error has been detected in the bit-inverted data; A communication terminal, comprising: reception processing means for performing a predetermined reception process. 2. A first error detecting means for detecting an error of received data to which an error correction code is added in advance based on the error correction code, and inverting each bit of the received data by one bit.
Bits of the received data to generate inverted bit inverted data.
And bit inversion means for the number of bits, and are provided corresponding to these bit inversion means.
The number of bits of the received data for detecting an error in the
Bit inversion data error detection means, and the bit inversion data error detection means
Bit inversion data for which no error was detected
Determining means for determining whether only one data exists, and an error detected by the first error detecting means;
The discrimination means detects an error in the bit-reversed data.
Zero or two or more bit-reversed data not output
Data, it is determined that the error cannot be corrected.
And a retransmission request unit for requesting retransmission to the transmission source of the communication terminal. 3. The communication terminal according to claim 1, wherein said error correction code is a cyclic redundancy check code. 4. A communication terminal according to any one of claims 1 to claim 3, wherein the received data was received in the data communication is not performed forward error correction.