JP2001144826A - Receiver and communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the efficiency of communication. SOLUTION: This receiver being the component of a communication system, where the length and/or the data rate of a communication frame is changed for every communication frame in accordance with that which encoding processing system is applied among plural encoding processing systems, is provided with a reception/demodulation means for receiving and demodulating the communication frame and generating the demodulated signal, plural decoding processing system which are composed of the number of systems, which corresponds to the encoding processing system for decoding demodulation data and generating plural pieces of decoding data, have functions symmetrical to the corresponding encoding processing systems and execute a decoding processing, and a selection means for selecting and outputting decoding data where an error is not detected by prescribed error detection as real decoding data from plural pieces of decoding data received from the decoding processing systems.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system, and is suitably applied to, for example, a case where the length of a message (frame) or data rate is changed for each frame in a mobile telephone or the like.

[0002] The present invention also relates to a receiving device as a component of such a communication system.

[0003]

2. Description of the Related Art Conventionally, in a communication system such as a cellular phone in which a frame length can be changed for each communication frame, a transmitting side adds control information to an overhead of the communication frame as control information.
By adding information on the changed frame length, the receiving side is explicitly notified of the frame length itself.

[0004] On the receiving side receiving the information, the received communication frame is processed normally by examining the frame length information of the overhead and specifying the frame length.
Can be decrypted.

[0005]

However, in such a conventional communication system, transmission and reception of frame length information requires an overhead of communication control, and the transmission of user information which is originally desired to be transmitted and received is required by the overhead. Efficiency decreases.

Further, the transmitting side needs a configuration and a processing procedure for adding the overhead, and the receiving side requires a configuration and a processing procedure for checking the overhead. Disadvantageous.

[0007]

In order to solve the above-mentioned problems, according to the present invention, among a plurality of predetermined encoding processing systems,
A receiving device as a component of a communication system in which the length and / or data rate of a communication frame can be changed for each communication frame depending on which coding processing system is applied, (1) receiving the communication frame Receiving and demodulating means for generating demodulated data by demodulating and demodulating the data; (2)
In order to generate a plurality of decoded data by decoding the demodulated data, the decoding system is composed of a number of systems corresponding to the encoding processing system, and each system has a function symmetric with the corresponding encoding processing system, and A plurality of decoding processing systems for performing decoding processing;
(3) selecting means for selecting, from among the plurality of decoded data received from these decoding processing systems, decoded data for which no error has been detected by predetermined error detection as authentic decoded data, and outputting the genuine decoded data. It is characterized by.

Further, in the communication system according to the present invention, the length and / or data rate of a communication frame to be transmitted according to which coding processing system is to be applied among a plurality of predetermined coding processing systems are determined. A transmission device that changes for each frame and a reception device according to claim 1 are provided.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION (A) Embodiment Hereinafter, an embodiment will be described with reference to an example in which a receiving apparatus and a communication system of the present invention are applied to a receiving section of a mobile telephone and a mobile telephone system.

(A-1) Configuration of the Embodiment FIG. 2 shows a mobile telephone system 10 of the embodiment. The receiver 11 shown in FIG.
3 may be mounted on the base station.

In FIG. 2, the mobile telephone system 10
Has a receiver 11, a transmission path 12, and a transmitter 13.

The transmitter 13 encodes and modulates transmission data SD, which is user information to be transmitted, to generate modulated data MD, and transmits the modulated data MD to the transmission line 12 by radio. is there. The transmitter 13 also
It has a function to change the frame length of transmission data for each frame.

The transmitter 13 modulates the modulated data MD to 5
The frame length is changed between ms and 20 ms. There is a relationship between frame length and data rate.
As shown in the figure, when the frame length is 5 ms, the data rate is 9600 bps (rate set No. 1), and when the frame length is 20 ms, there are four data rates from 1500 bps to 9600 bps (rate set Nos. 2 to 5). obtain.

The data rate described here is substantially the data rate of the information sequence to be communicated, and is not the apparent external data rate that is increased by the repetition processing described later. In the present embodiment, the external data rate is constant even when the rate set No. is switched.

FIG. 3 describes the mode of decoding in the receiver 11.
Since the encoding performed in X is also a process symmetric to the decoding, the encoding will be described with reference to FIG.

As is apparent from FIG. 3, the encoding unit CSX
Performs the encoding corresponding to the rate set Nos. 1 to 5
Assuming that there are three coding modes and one coding mode corresponds to one coding system, the coding unit CSX has a total of five parallel coding systems CS1 to CSN.

For example, if the coding system CS1 has a rate set
Corresponding to No. 1, the coding system CS2 is the rate set No. 2
.., The coding system CSN (N = 5) corresponds to the rate set No. 5.

The transmission path 12 in FIG. 2 is a radio communication path, and the receiver 11 receives the modulated data MD from the transmission path 12.

The coding unit CSX of the transmitter 13 has a unified coding unit CC before the coding systems CS1 to CS5.
It has. The unified coding unit CC performs, for example, convolutional coding, and outputs the coding result to the coding system CS.
1 to a portion for parallel output to CSN.

On the other hand, a rake (RA
KE) Receiver 20, Decoder 21, CRC (Cyclic Redundancy Check: Cyclic Redundancy Ch)
eck) determining section 22 is provided.

The rake receiving unit 20 is provided for performing site diversity and performing soft handoff in the CDMA (code division multiple access) type mobile telephone system 10 using the same frequency in adjacent cells.

The decoding unit DSX of the decoder 21 includes five decoding systems DS connected in parallel to the output terminal of the rake receiver 20.
1 to DS5 (DSN: N = 5) and one unified decoding unit V
C. In the decoder 21, the decoding system D
S1 corresponds to the encoding system CS1, and the decoding system DS2
Corresponds to the coding system CS2, the decoding system DS3 corresponds to the coding system CS3, the decoding system DS4 corresponds to the coding system CS4, and the decoding system DS5 corresponds to the coding system CS5. I do.

The decoding system DS1 includes a deinterleaver DI1 and a depletion unit DR1 connected in this order, and the decoding system DS2 connects a deinterleaver DI2 and a depletion unit DR2 in this order. The decoding system DS3 includes a deinterleaver DI.
3, a depuncture unit DP3, and a depletion unit DR
3 are connected in this order, and the decoding system DS4 includes a deinterleaver unit DI4, a depuncture unit DI4,
The decoding system DS5 is configured by connecting the deinterleaving unit DI5, the depuncturing unit DP5, and the depletion unit DR5 in this order.

The deinterleaver section such as the deinterleaver section DI1 changes the state of the data series subjected to the interleaver processing (interleave) performed by the encoder CSX of the transmitter 13 to the state before the interleaver processing is performed. This is the process of returning to.

The interleaver process is a process of changing the arrangement order of the data series within a predetermined range such as 1536 symbols according to a predetermined regularity. Therefore, the deinterleaver process is performed within the range. In other words, according to the regularity corresponding to the regularity, the order of arrangement of the data series is restored.

The depletion unit such as the depletion unit DR1 changes the state of the data series subjected to the repetition processing (repeat) performed by the encoding unit CSX of the transmitter 13 to the state before the repetition processing is performed. This is the process of returning to.

The repetition process is a process of repeating a data sequence according to the number of repetitions. For example, if the data sequence is “1, 2, 3,...” With the number of repetitions 2, the data sequence becomes “1,
1, 2, 2, 3, 3, ... ".

Therefore, in the depletion processing for this, the repetition of the data sequence is removed according to the number of repetitions. In this case, the data sequence is changed to “1, 1, 2, 2, 3, 3,. From "1, 2,
3, ... ".

Finally, in the depuncturing section such as the depuncturing section DP3, the state of the punctured data sequence performed by the encoding section CSX of the transmitter 13 is returned to the state before the puncturing processing is performed. Processing.

The puncturing process is executed on the premise that the transmission of the same data is continued by the coding method on the transmitter 13 side, and a part of the data is removed from the continuous data series at a preset rate. This is the processing to be performed. For example, the data series "1,1,1,1, ..." is converted to "1,1,1, ..." by the puncturing process.

Therefore, in the depuncturing process, the data is inserted into the received data sequence at a rate corresponding to the rate. By this depuncturing processing, for example, the data series "1,1,1, ..." is converted into the data series "1,1,1,1, ...".

The puncturing process and the repetition process are processes that affect the data rate in nature, and the interleaver process is a process that does not affect the data rate.

The reason why no depuncturing processing section exists in the decoding systems DS1 and DS2 is that puncturing processing is not performed in the corresponding coding systems CS1 and CS2.

Further, the arrangement order of the deinterleaver, depuncture, and depletion units in each of the decoding systems DS1 to DS5 corresponds to the processing order of the interleaver processing, puncturing processing, and repetition processing in the corresponding coding systems CS1 to CS5. And just in reverse order.

Therefore, in the coding system CS1 corresponding to the decoding system DS1, the repetition processing is first performed, then the interleaver processing is performed, and in the coding system CS2 corresponding to the decoding system DS2, the repetition processing is performed first. Then, an interleaver process is performed next, and in a coding system CS3 corresponding to the decoding system DS3, a repetition process is performed first, and then a puncturing process and an interleaver process are performed in this order, and a code corresponding to the decoding system DS4 is processed. In the coding system CS4, first, a repetition process is performed, then a puncturing process and an interleaver process are performed in this order, and the coding system CS corresponding to the decoding system DS5.
In 5, the repetition processing is performed first, and then the puncturing processing and the interleaver processing are performed in this order.

Further, the detailed mode of each processing also corresponds between the corresponding encoding system and decoding system.

Further, for example, even in the same depletion processing, the processing performed in the depletion sections DR2 to DR5 differs in the number of repetitions, and there is a similar difference in the depuncturing section and the deinterleaver section. As an example, since the repetition processing of the number of repetitions 2 is performed in the repetition processing of the encoding system CS2, the depletion unit DR2 of the decoding system DS2 performs the depletion processing of the number of repetitions 2.

In this embodiment, five encoding systems CS1
To CS5 are all repetition processes, the last of the five decoding systems DS1 to DS5 are all depletion processing units DR1 to DR5.

In short, the contents of processing performed in each of the decoding systems DS1 to DS5 correspond to each rate set No. in FIG.

That is, the processing performed in the decoding system DS1 corresponds to the rate set No. 1, the processing performed in the decoding system DS2 corresponds to the rate set No. 2,
The processing performed in the decoding system DS4 corresponds to the rate set No. 3, the processing performed in the decoding system DS4 corresponds to the rate set No. 4, and the processing performed in the decoding system DS5 corresponds to the rate set No. 3.
Corresponding to 5.

The processing data DD1 to DD5 in the middle of decoding output from the five decoding systems DS1 to DS5 are supplied to a common Viterbi decoding unit VC.

The Viterbi decoding unit VC includes one Viterbi decoder (not shown) for executing Viterbi decoding corresponding to the convolutional encoding of the unified encoding unit CC, and a time-division unit provided at an input unit of the Viterbi decoder. It includes a multiplexer for multiplexing and a demultiplexer for demultiplexing provided at the output of the Viterbi decoder.

The processed data DD1 to DD5 are time-division multiplexed by the multiplexer and supplied to a common Viterbi decoder, so that the Viterbi decoding result is obtained in a time-division multiplexed state. The Viterbi decoding result is demultiplexed by the demultiplexer and converted into decoded data VD1 to VD5.

That is, the Viterbi decoding unit VC performs the Viterbi decoding of the processing data DD1 so that the decoded data V
D1 is obtained, and the decoded data VD2 is obtained by Viterbi decoding of the processed data DD2.
Is decoded to obtain decoded data VD3. Viterbi decoding of processed data DD4 yields decoded data VD4. Viterbi decoding of processed data DD5 yields decoded data VD5.

Each of the decoded data VD1 to VD5 is transmitted to the next stage C
A corresponding CRC operation unit P provided in the RC determination unit 22
1 to P5 and receive error detection.

That is, the decoded data VD1 is subjected to error detection by the CRC operation unit P1, and the decoded data VD2 is
An error is detected by the RC operation unit P2, and the decoded data V
D3 receives an error detection by the CRC calculation unit P3, the decoded data VD4 receives an error detection by the CRC calculation unit P4, and the decoded data VD5 receives an error detection by the CRC calculation unit P5.

If the transmitter 13 has the coding system CS1
In the case where encoding has been performed by using the CRC operation unit P1
Should be output as no error because the CRC matches, and the error detection results of the other CRC calculation units P2 to P5 should be output as having an error.

Here, the CRC calculation units P1 to P5 can also function to detect an error of a normal meaning in a communication path such as the transmission path 12, but rather, the above-mentioned rate set No. used by the transmitter 13 is used. Works to identify.
If the rate set No. is different from the one used by the transmitter 13, the combination of the data rate and the frame length will be different, and normal decoding will not be performed, as in the case where a normal transmission error occurs. An error is detected by the CRC calculation units P1 to P5.

Among the five CRC calculation sections P1 to P5, the CRC calculation section that has output without error is selected by the selector (SE).
L) By controlling the control input terminal 23A of 23, the selector 2
3 causes its output terminal to be selected. At this time, the output of the CRC operation unit is transmitted from the selector 23 as the reception data RD.

For example, in the above-described case where the transmitter 13 performs encoding using the encoding system CS1, the CRC operation unit P1 causes the selector 23 to select its own output terminal, so that the decoded data VD1 From the CRC determination unit 22.

Hereinafter, the operation of the present embodiment having the above configuration will be described.

(A-2) Operation of Embodiment The rate set that can be used in the mobile telephone system 10 is as follows.
As shown in FIG. 3, there are five rate sets No. 1 to No. 5.

Of these, in rate set No. 1, the frame length is 5 ms, the data rate is 9600 bps, no depuncturing (or puncturing) is performed, the number of repetitions of depletion (repetition) is 2, and the deinterleaver is repeated. Processing (interleaver processing)
Is performed within the range of 384 symbols.

In rate set No. 2, the frame length is 20 ms, the data rate is 1500 bps, the depuncturing process is not performed, the number of repetitions of the depletion process is 16, and the deinterleaver process is performed within the range of 1536 symbols.

Similarly, in rate set No. 3, the frame length is 20 ms, the data rate is 2700 bps, the depuncturing process is 1 of 5, that is, one symbol is inserted for every five symbols, the number of repetitions of the depletion process is 16, and the deinterleaver process is 1536 symbols. It is performed in the range.

Further, in the rate set No. 4, the frame length is 20 ms, the data rate is 4800 bps, the depuncturing process is 1of9, that is, one symbol is inserted for every 9 symbols, the number of repetitions of the depletion process is 4, and the deinterleaver process is 1536 symbols. In rate set No. 5, the frame length is 20 ms, the data rate is 9600 bps, the depuncturing process is 1 of 9, that is, one symbol is inserted for every 9 symbols, the number of repetitions of the depletion process is 2, and the deinterleaver process is 1536 symbols. Done.

By switching the rate set No., the transmitter 13 changes the frame length, the data rate, the presence or absence of the puncturing process, the mode of the repetition process, and the mode of the interleaver process for each frame. Will do.

Assuming that the transmitter 13 is transmitting the modulated data MD in the rate set No. 3 mode, the receiver 11 receives the modulated data MD via the transmission line 12.

In the receiver 11, the rake receiving unit 20
Receives the demodulated data MD and demodulates it to output demodulated data DM. The demodulated data DM is simultaneously supplied to five decoding systems DS1 to DS5 in the decoder 21.

As described above, since the decoding system that performs the process corresponding to the rate set No. 3 is only the decoding system DS3, the processing data DD output from the decoding system DS3 is used.
Only the decoded data VD3 corresponding to the CRC
It is determined that there is no error by (the CRC calculation unit P3),
All other decoded data VD1, VD2, VD4, VD5 are determined to have errors. Therefore, the selector 23 uses only the decoded data VD3 as final decoded data,
Output as reception data RD.

When the transmitter 13 transmits the next frame at the rate set No. 1, the receiver 11 that receives and processes the next frame decodes the decoded data corresponding to the processed data DD1 output from the decoding system DS1. It is determined that only VD1 has no error, and the VD1 is CR
This is output from the C determination unit 22.

The same operation is repeated thereafter, and the transmitter 1
Even if the receiver 11 does not notify the receiver 11 of the fact that the rate set No. has been switched and the control information for identifying the switched rate set No.
On the one side, it is possible to obtain normal received data RD. That is, the receiver 11 can perform blind determination of the rate set No. used by the transmitter 13.

In the above, only the downlink channel from the base station equipped with the transmitter 13 to the mobile telephone equipped with the receiver 11 has been described. For processing, the mobile telephone will have an encoding unit similar to the transmitter 13 and the base station will have a decoder and CRC determination unit similar to the receiver 11.

(A-3) Effects of Embodiment According to the present embodiment, the receiver side can normally receive the control information itself such as the changed data rate and the changed frame length without transmitting the control information from the transmitter to the receiver. In this case, it is possible to perform proper decoding and obtain normal received data, so that the transmission efficiency of user information is high and the communication efficiency is high.

In this embodiment, the transmitting side can omit a configuration and a processing procedure for generating and transmitting control information itself such as a frame length, and the receiving side decodes and processes the control information. Can be omitted.

Further, in the present embodiment, in the existing mobile telephone system, the decoder (21) and the CR
Since it can be realized by incorporating the function of the C determination unit (22), it is also excellent in feasibility.

(B) Other Embodiments In the above embodiment, the coding unit CSN and the decoding unit DSN are provided with five parallel coding systems CS1 to CS5 corresponding to the rate sets No. 1 to 5, respectively. Decoding system DS1-D
Although S5 is provided, this number may be more or less than 5.

In the case of the encoding unit CSX on the transmitter 13 side, unlike the decoding unit DSX on the receiver 11 side, each system does not need to have a parallel structure in hardware.
By changing the mode of software-based coding processing by one system in hardware, the coding unit CS
X may have the same function as X.

For example, the depletion units DR1 to DR5
Are connected serially to five repetition units corresponding to the above, a depuncture unit corresponding to each of the depuncture units DR3 to DR5, an interleaver unit corresponding to the deinterleaver unit DR1, an interleaver unit corresponding to the deinterleaver units DR2 to DR5, and the like. The encoding unit may be configured in such a manner. In this case, a portion that simply passes the transmission data SD (for example, an interleaver unit) and a portion that performs processing (for example, an interleaver unit) change according to the rate set No. to be used.

In this case, the "encoding processing system" in claim 1 is not a concept fixed in hardware but a concept designating a function to be changed in software.

The rake reception used in the above embodiment is not an essential requirement for the present invention.

Further, in the above embodiment, the Viterbi decoding unit VC has a built-in multiplexer and demultiplexer and decodes the time-division multiplexed processing data DD1 to DD5. Viterbi decoding may be performed in parallel on one piece of processing data DD1 to DD5.

In this case, five Viterbi decoders inside the Viterbi decoding unit VC are required, which is disadvantageous in that the circuit scale is increased, but is more advantageous than the above embodiment in terms of processing speed and processing capability.

In the above embodiment, the final output from the receiver 11 is only the normal received data RD. However, for example, any one of the CRC calculation units P1 to P5 has an error. Depending on whether it is determined that there is no data, a rate set number used for communication or one characteristic value (for example, data rate 9600 bps) in the rate set number itself is output, and the output is output to the receiver 11.
It may be used on the side.

Further, the present invention can be applied to the case where the length and data rate of a message (frame) are changed for each frame, so that it is naturally applicable to communication systems other than the mobile telephone system. is there.

Further, the present invention can be realized by incorporating a function corresponding to the decoding unit DSX and the CRC determination unit 22 in the existing communication system, so that the present invention is also excellent in feasibility.

That is, according to the present invention, the length and / or data rate of a communication frame is changed for each communication frame in accordance with which coding processing system among a plurality of predetermined coding processing systems is applied. The present invention can be widely applied to a receiving device as a component of a communication system to be obtained, and a communication system including such a receiving device.

[0078]

As described above, according to the present invention, it is not necessary to notify the changed communication frame length, data rate, and the like by communication from the transmitting device to the receiving device. Increase.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an overall configuration of a mobile telephone system according to an embodiment.

FIG. 2 is a schematic diagram showing a main part of a receiver used in the mobile telephone system according to the embodiment.

FIG. 3 is an explanatory diagram showing an operation of the embodiment.

[Explanation of symbols]

10: Mobile telephone system, 11: Receiver, 12: Transmission line, 13: Transmitter, 21: Decoder, 22: CRC determination unit, CS1 to CSN: Encoding system, DS1 to DS5: Decoding system.

Claims (2)

[Claims] 1. A communication system in which the length and / or data rate of a communication frame can be changed for each communication frame in accordance with which coding processing system among a plurality of predetermined coding processing systems is applied. In a receiving device as a component, a reception demodulation unit that generates demodulated data by receiving and demodulating the communication frame; and the encoding processing system for decoding the demodulated data to generate a plurality of decoded data. , Each system has a function symmetric to the corresponding encoding processing system, and performs a plurality of decoding processing systems that simultaneously perform decoding processing, and a plurality of decoding systems received from these decoding processing systems. Selecting means for selecting, as genuine decoded data, decoded data from which no error has been detected by predetermined error detection from among the decoded data, and outputting the genuine decoded data. Receiving device. 2. A transmission apparatus for changing a length and / or a data rate of a communication frame to be transmitted for each communication frame according to an encoding processing system to be applied among a plurality of predetermined encoding processing systems. A communication system comprising: the receiving device according to claim 1.