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Addition comparison selection calculation method and addition comparison selection calculation device in radix-4 algorithm

A computing device and computing method technology, applied in the field of communication, can solve problems such as large delay and uneconomical, and achieve the effects of improving performance, reducing critical path delay, and increasing decoding rate

Active Publication Date: 2015-12-16
BEIJING SMART LOGIC TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method has a relatively large delay. After the calculation of the state measurement value is completed by the addition and comparison, it is necessary to add several levels of comparison and subtraction operations. The time consumption is equivalent to the addition and comparison operation. This method is not cost-effective.

Method used

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  • Addition comparison selection calculation method and addition comparison selection calculation device in radix-4 algorithm
  • Addition comparison selection calculation method and addition comparison selection calculation device in radix-4 algorithm
  • Addition comparison selection calculation method and addition comparison selection calculation device in radix-4 algorithm

Examples

Experimental program
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Effect test

Embodiment 1

[0034] Example 1: Select the smallest number among the four data

[0035] The four temporary state metric values ​​SUM0, SUM1, SUM2 and SUM3 are compared in pairs, and the comparison result is marked with 0 or 1. If SUM0 is greater than SUM1, it is recorded as 0, otherwise it is recorded as 1; if SUM0 is greater than SUM2, it is recorded as 0, otherwise it is recorded as 1; and so on, six groups of comparison results are obtained. According to the comparison result, it is judged which number among the four temporary state metrics is the smallest. The logic of selecting the smallest number among the four data is shown in Table 1:

[0036] Table I

[0037]

[0038]

Embodiment 2

[0039] Example 2: Select the largest number among the four data

[0040] The four temporary state metric values ​​SUM0, SUM1, SUM2 and SUM3 are compared in pairs, and the comparison result is marked with 0 or 1. If SUM0 is greater than SUM1, it is recorded as 0, otherwise it is recorded as 1; if SUM0 is greater than SUM2, it is recorded as 0, otherwise it is recorded as 1; and so on, six groups of comparison results are obtained. According to the comparison results, determine which of the four numbers is the largest. The logic for selecting the largest number among the four temporary state metrics is shown in Table 2:

[0041] Table II

[0042]

[0043]

[0044] The present invention also proposes an addition ratio selection calculation device under a radix-four algorithm, such as Figure 7 As shown, the device includes:

[0045] Adders (601, 602, 603, 604): including four adders, the input of each adder is a branch metric value and the corresponding state metric val...

Embodiment

[0049] Embodiment: Select the smallest state metric value among the four state metric values

[0050] First, the branch metric values ​​of the four branches and the state metric values ​​at the previous moment are respectively sent to four adders to obtain the temporary state metric values ​​of the four branches; the temporary state metric values ​​of the four branches are respectively compared with the previous moment The state metric value of the 0 state is subtracted and reduced to obtain the state metric value after the reduction operation of the four branches; at the same time, the temporary state metric values ​​of the four branches are sent to six comparators in pairs. , the output of the comparator is used as the strobe signal of the selector, and the smallest one is selected from the state measurement values ​​after the reduction operation of the four branches, that is, the update work of the state measurement value is completed.

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Abstract

The invention discloses an addition comparison selection calculation method in a radix-4 algorithm. The addition comparison selection calculation method comprises the following steps: adding a branch measurement value to a corresponding state measurement value to obtain four temporary state measurement values; pairwise comparing the four temporary state measurement values, and simultaneously, respectively subtracting a certain state measurement value at a previous time from the four temporary state measurement values so as to obtain statute operated state measurement values; and selecting the maximal / minimal value in the four statute operated state measurement values as new state measurement values according to a comparison result. The invention further discloses an addition comparison selection calculation device in the radix-4 algorithm. According to the invention, the critical path delay of a decoding unit can be reduced; the decoding rate can be increased; and thus, the decoding performance of the whole system can be improved.

Description

technical field [0001] The invention relates to the field of communication, in particular to a calculation method and device for addition, comparison and selection under the radix-four algorithm. Background technique [0002] In order to meet the demands of today's society on digital traffic and improve the error correction capability of the system, channel coding technology is becoming more and more important. Since Elias first proposed convolutional coding for discrete memoryless channels in 1955, various improvements and optimization algorithms for convolutional codes have emerged in an endless stream. In 1967, AndrewJ.Viterbi proposed a dynamic programming decoding algorithm for convolutional codes - viterbi algorithm, which is a maximum likelihood decoding algorithm, by decoding the input information bit by bit, find the corresponding The sequence with the closest distance to the received sequence is output as the decoding. When the code constraint length is relativel...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03M13/23H03M13/41
Inventor 赵旭莹王晓琴吴军宁田燕
Owner BEIJING SMART LOGIC TECH CO LTD
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