JP2001285086A - Equipment and method for communication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide communications equipment and a communicating method, capable of accelerating processing clock. SOLUTION: An ACS part 2 inputs the 1st and 2nd metric values of each state and generates a 3rd new metric value. The part 2 also calculates selection information from the difference of the metric values. The part 2 further selects and outputs the 3rd metric value, on the basis of the calculated selection information. Thus, the 1st and 2nd metric values of each state are inputted to an operation processor 1, the 3rd new metric value is generated, the selection information is calculated from the difference of the metric values, the metric value is selected and outputted on the basis of the calculated selection information and the processing clock can be accelerated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device having an arithmetic device and a communication method.

[0002]

2. Description of the Related Art Conventionally, in data communication on a communication line, a bit error frequently occurs, so that it is necessary to perform an error correction process. As a method of error correction, there is a method of decoding a convolutional code generated from information bits by Viterbi decoding on a receiving side.

In a communication apparatus employing such Viterbi decoding, decoding characteristics can be improved by decoding using soft decision information, which is information on the degree of certainty. You are decrypting. Thus, by using Viterbi decoding, decoding of a convolutional code can be realized by repeating simple processing of addition, comparison, and selection and finally by traceback for decoding data.

In recent years, since turbo codes have been adopted for error correction, some communication devices perform turbo decoding when decoding. An element decoder for turbo decoding uses a soft-output Viterbi decoder or a MAP decoder that performs maximum a posteriori probability decoding.

For example, there is a method for decoding a communication device disclosed in Japanese Patent Laid-Open Publication No. Hei 3-212820 (Viterbi decoder). In this decoder, an arithmetic unit for performing a square operation of a difference between a sample value and an expected value of input data, an ACS circuit for adding an output of the arithmetic unit, and information obtained by selecting an ACS circuit having a small square error are used. Some include a bus memory to be added, a bus selector to add the output of the last stage of the bus memory, and a normalization circuit. In this communication device, the number of bits of the metric value obtained by accumulating the square errors of the ACS circuit and the normalization circuit can be reduced to such an extent that the error rate is not affected.

[0006]

However, in the conventional communication device, when a series of arithmetic processing is performed within one sample (one clock), a time longer than the total processing time of each adder is required. Therefore, the speed of the clock, which is one sample, may decrease. become. further,
When the number of bits of the soft decision value increases, the processing delay in the ACS circuit and the overflow control circuit increases, and the clock speed may decrease.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a communication device and a communication method capable of increasing the processing clock speed.

[0008]

In order to achieve the above object, a communication apparatus according to the present invention inputs a first metric value and a second metric value of each state and sets a new third metric value. Metric value generation means for generating, selection information calculation means for obtaining selection information from a difference between metric values, and selection output means for selecting and outputting a metric value based on the selection information calculated from the selection information calculation means, It is configured to have.

With this configuration, a new third metric value is generated by inputting the first metric value and the second metric value of each state, and selection information is obtained and calculated from a difference between the metric values. The metric value is selected and output based on the selected information, and the processing clock can be speeded up.

An arithmetic unit for a communication device according to the present invention includes: a metric value generating means for inputting a first metric value and a second metric value of each state to generate a new third metric value; A selection information calculating means for obtaining selection information from a difference, and a selection output means for selecting and outputting a third metric value based on the selection information calculated by the selection information calculation means are provided.

With this configuration, the first metric value and the second metric value of each state are input to the arithmetic unit to generate a new third metric value, and the selection information is obtained from the difference between the metric values. , A metric value is selected and output based on the calculated selection information, and the processing clock can be speeded up.

An arithmetic unit for a mobile station communication device according to the present invention comprises:
Metric value generating means for inputting the first metric value and the second metric value of each state to the mobile station to generate a new third metric value; selection information calculating means for obtaining selection information from a difference between the metric values; And a selection output unit that selects and outputs a third metric value based on the selection information calculated by the selection information calculation unit.

[0013] With this configuration, the mobile station inputs the first metric value and the second metric value of each state into the arithmetic unit, generates a new third metric value, and generates a difference between the metric values. Request selection information from
A metric value is selected and output based on the calculated selection information, and the processing clock can be sped up.

An arithmetic unit for a base station communication device according to the present invention comprises:
Metric value generating means for inputting the first metric value and the second metric value of each state to the base station to generate a new third metric value; selection information calculating means for obtaining selection information from a difference between the metric values; And a selection output unit that selects and outputs a third metric value based on the selection information calculated by the selection information calculation unit.

[0015] With this configuration, the base station inputs the first metric value and the second metric value of each state into the arithmetic unit, generates a new third metric value, and calculates the difference between the metric values. Request selection information from
A metric value is selected and output based on the calculated selection information, and the processing clock can be sped up.

According to the communication method of the present invention, a step of inputting a first metric value and a second metric value of each state to generate a new third metric value, and a step of obtaining selection information from a difference between the metric values And a step of selecting and outputting the third metric value based on the calculated selection information.

In this manner, a new third metric value is generated by inputting the first metric value and the second metric value of each state, and selection information is obtained from the difference between the metric values to calculate the selection information. The metric value is selected and output based on the selected information, and the processing clock can be speeded up.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An object of the present invention is to increase the speed of a processing clock.

(Embodiment 1) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an arithmetic unit for a communication device according to Embodiment 1 of the present invention.

Referring to FIG.
The adder Add1 in the S section 2 calculates a first metric value (branch metric value). The adder Add2 has a second metric value (bus metric value)
Is calculated. The adder Add3 is ACS
The path metric value is calculated as part of the calculation.

The selector 6 selects two newly generated metric values. ACS part 2
The adders Add1 and Add2 perform calculation for obtaining a delta value which is a difference between path metric values.

FIG. 1 shows a case where the constraint length K = 3 and the reception signal is decoded by the convolutional encoder shown in FIG.
FIG. 5 is a block diagram illustrating an output Viterbi decoder including the arithmetic device illustrated in FIG. 4.

In the output Viterbi decoder shown in FIG.
The CS unit 2 outputs a branch metric value and a metric based on an output of the branch metric calculation unit 3 that calculates a branch metric value based on a sample value (judgment signal) of the received signal of the convolutional code and an output of the overflow control circuit 4. The values are added, a path metric value is calculated, each path metric value is compared, and a path metric value is selected.

After the selection of the path metric value, the path metric value is output. In the arithmetic processing device 1, the output of the ACS unit 2 is output from the arithmetic result memory unit 8 to the delta value selection information, which is the difference between the path metric values of the traceback unit 5, and the delta value, which is the difference between the metric value and the path metric value. Store the value. The path selector 7 selects a delta value, which is a difference between path metric values, from the selection information stored in the operation result memory unit based on the output of the operation result memory unit 8.

The branch metric calculation unit 3 calculates a branch metric value from the sample value (judgment signal) of the received signal and outputs it to the ACS unit 2. The branch metric value is calculated according to the transition of the convolutional encoder. ACS
The unit 2 has four arithmetic units 2a to 2d, each of which has metric values M00 to M11 of each state and selection information PS.
The operation of PS11 is performed from 00.

The ACS unit 2 also has a
Delta value D00, which is the difference between the bus metric values, is applied to the S circuit.
And a circuit for performing the operations of D11 to D11, and performs processing in parallel with the operation corresponding to the ACS operation. The most significant code bits from delta D00 to D11 are selection information PS00
To PS11.

For example, a description will be given assuming that the following equations (1) to (4) hold. D00 = (P00 + BR00)-(P01 + BR11) (1) D01 = (P11 + BR01)-(P01 + BR10) (2) D10 = (P01 + BR01)-(P11 + BR10) (3) ) D11− (P10 + BR01) − (P11 + BR01) (4)

When these equations are expanded, the following equations are obtained. D00 = (M00-M01) + (BR00-BR11) (5) D11 = (M11-M10) + (BR01-BR10) (6) D10 = (M01-M00) + (BR00-BR11) (7) D11 = (M10-M11) + (BR01-BR10) (8)

Equations (5) to (8) can be operated by three adders. As described above, the delta values D00 to D11, which are the differences between the path metric values, and the selection information P
By performing the operations of S00 to PS11 by cascade connection of three adders in two stages, the processing clock can be speeded up.

In the convolutional encoder 20 shown in FIG. 2, the information bit “1” is changed to “X” and the information bit “0” is changed to “−”.
When modulated to “X”, the branch metric values BR00 and BR01 inverted by the inverters 22 and 23 correspond to BR11 and BR10, respectively. The adders 21 and 24 add the input data, and the output of the adder 24 is output data.

In the formulas (5) to (8), BR11 and BR10 can be used without performing the calculation, but by inverting each of them. This can be modeled as in FIG.

In FIG. 3, the encoder performs addition in adders 32 to 34 based on the output from the overflow control circuit 37, and performs division in the arithmetic unit 31 based on a signal corresponding to the branch metric value. Has become.

The addition is performed in the adder 36 based on the output of the arithmetic unit 31 and the output of the adder 32 to obtain the selection information and the delta value. Furthermore, selector 3
In 5, the metric value is selected based on the output of the adder 36 and the outputs of the adders 33 and 34.

FIG. 5 shows the operation of the element signal unit 51 based on the input of the received signal, the interleaver 52 and the element decoder 5.
3. A circuit 50 for operating the deinterleaver 54 in order to obtain decoded data.

FIG. 6 shows the configuration of the mobile station communication device 50, and FIG. 7 shows the configuration of the base station communication device. The mobile station in FIG. 6 includes an antenna 60, a radio unit 61, a baseband processing device 67, an interface unit 62, a display unit 63, a key input unit 65, a speaker 64, and a microphone 66. In the base station, the antenna 7
0, a wireless unit 71, a baseband processing device 73, and a network interface unit 72.

The three adders described above are vertically connected in two stages to calculate the delta value, which is the difference between the metric values, and the selection information, or one divider and two adders are used. The processing clock can be sped up by connecting the cascade vertically to obtain the delta value which is the difference between the bus metric values and the selection information.

[0037]

According to the present invention as described above,
A communication device and a communication method capable of increasing the processing clock speed can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an arithmetic processing device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a modified example of the first embodiment of the present invention;

FIG. 3 is a block diagram showing a configuration of a modified example of the first embodiment of the present invention;

FIG. 4 is a block diagram showing a configuration of a modified example of the first embodiment of the present invention;

FIG. 5 is a block diagram showing a configuration of a modified embodiment of the first embodiment of the present invention;

FIG. 6 is a block diagram showing a configuration of a mobile station communication device.

FIG. 7 is a block diagram illustrating a configuration of a base station communication device.

[Explanation of symbols]

Reference Signs List 1 arithmetic processing device (communication device) 2a to 2d ACS unit (metric value generation unit, selection information calculation unit, selection information calculation unit) 3 branch metric unit (branch metric unit) 4 digit overflow control circuit 5 traceback unit 6 selector 7 Bus select section 8 Operation result memory section

Claims (5)

[Claims] 1. A first metric value and a second metric value for each state.
Metric value generating means for generating a new third metric value by inputting the metric value, selecting information calculating means for obtaining selection information from a difference between the metric values, and the selection information calculated from the selection information calculating means. Selection output means for selecting and outputting the metric value based on
A communication device comprising: 2. A first metric value and a second metric value for each state.
Metric value generating means for generating a new third metric value by inputting the metric value, selecting information calculating means for obtaining selection information from a difference between the metric values, and the selection information calculated from the selection information calculating means. And a selection output means for selecting and outputting the third metric value based on the metric value. 3. A metric value generating means for inputting a first metric value and a second metric value of each state to a mobile station to generate a new third metric value, and selecting information from a difference between the metric values. Mobile station communication, comprising: selection information calculation means to be obtained; and selection output means for selecting and outputting the third metric value based on the selection information calculated by the selection information calculation means. Arithmetic unit for the device. 4. A metric value generating means for inputting a first metric value and a second metric value of each state to a base station to generate a new third metric value, and selecting information from a difference between the metric values. Base station communication, comprising: selection information calculation means to be obtained; and selection output means for selecting and outputting the third metric value based on the selection information calculated by the selection information calculation means. Arithmetic unit for the device. 5. A first metric value and a second metric value for each state.
Generating a new third metric value by inputting the metric value of the above, obtaining the selection information from the difference between the metric values, selecting the third metric value based on the calculated selection information, Outputting a communication method.