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Method for updating soft information and demodulating equipment

A technology of soft information and input information, applied in the field of Viterbi algorithm in the field of wireless communication technology

Inactive Publication Date: 2012-05-23
ZTE CORP
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  • Description
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Problems solved by technology

However, we can see the disadvantages of this method. The difference between the cumulative metrics between multiple paths to a state is taken as the reliability value between different symbols at this moment, that is, the formula (8) is equivalent to the following formula

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  • Method for updating soft information and demodulating equipment
  • Method for updating soft information and demodulating equipment
  • Method for updating soft information and demodulating equipment

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Embodiment Construction

[0038] From figure 1 It can be seen that in the SOVA-1 algorithm, for each state at each moment in the advancement process of the VA algorithm, the path to reach this state is selected from the input information u i = 0 causes the path set to have the minimum cumulative metric path path_0 (indicated by the solid line with an arrow in the figure), and is determined by the input information u i =1 causes the path set to have the minimum cumulative metric path path_1 (indicated by the dotted line with an arrow in the figure), and the difference between the cumulative metrics of these two paths is used as the soft information value of the state at this moment.

[0039] In the above method, use p'(u i =0|y i ) because it is not the real p(y i =0|y i ), it only considers the state at each moment on the optimal path by u i = 0 causes the probability of the path, the real p(u i =0|y i ) according to the total probability formula should be all u at this moment i = the sum of th...

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Abstract

The invention discloses a method for updating soft information and demodulating equipment. The method applied to soft output Viterbi comprises the following steps of: dividing all state transitions from the last moment to the current time into two sets, setting a set of state transitions caused by an input information bit value of 0 as a first state transition set, setting a set of state transitions caused by an input information bit value of 1 as a second state transition set, and taking the difference between the minimum cumulative metric selected from the first state transition set and the minimum cumulative metric selected from the second state transition set as a soft information value of the current time. The soft output Viterbi algorithm (SOVA)-1 is improved, and only one soft information value is stored at one moment; and compared with an SOVA-1 of storing a soft information value in each state at each moment, the method has the advantages that: the storage capacity can be greatly saved, backtracking is not required, and the decoding performance is improved on the basis of maintaining the computational complexity of the SOVA-1.

Description

technical field [0001] The present invention relates to a Viterbi (VA for short) algorithm in the field of wireless communication technology, in particular to a method for updating soft information and a demodulation device. Background technique [0002] In the process of wireless communication, the sending end sends the data to the receiving end through the wireless link. During the transmission process, the data will encounter the influence of white noise, intersymbol interference and co-channel interference. How to accurately obtain the Sending signals is a challenging task. For this reason, source coding, channel coding, and modulation techniques are introduced at the sending end, and demodulation, channel decoding, and source decoding are carried out at the receiving end. [0003] The Maximum Likelihood Sequence Estimation (MLSE) criterion is a criterion commonly used in demodulation devices, and the Viterbi (VA) algorithm is an effective algorithm commonly used to rea...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L1/00H03M13/41
CPCH03M13/41H03M13/4146H04L1/00
Inventor 张淑娟杨锋卢勤博
Owner ZTE CORP