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Hybrid automatic request retransmission method, transmitter, receiver and communication system

A hybrid automatic and transmitter technology, applied in the field of communication, can solve the problem of reducing the overall capacity and performance of the system, and achieve the effect of reducing the amount of feedback information and improving reliability and effectiveness

Inactive Publication Date: 2009-01-07
NTT DOCOMO INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] Moreover, if the retransmitted data includes unnecessary information, it will reduce the overall capacity and performance of the system

Method used

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  • Hybrid automatic request retransmission method, transmitter, receiver and communication system
  • Hybrid automatic request retransmission method, transmitter, receiver and communication system
  • Hybrid automatic request retransmission method, transmitter, receiver and communication system

Examples

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Comparison scheme
Effect test

example 1

[0047] Assuming that transmitter 1 adopts high-order modulation 16QAM, the code rate is 1 / 2, and the spectral efficiency is 2bps / Hz, then receiver 2 decodes according to MAP, calculates the value of the logarithmic likelihood ratio of each information bit, and compares these The absolute values ​​of the values ​​are sorted.

[0048] Acquisition unit 22 determines the least reliable information bit equal to the threshold according to the given retransmission information bit threshold value A; finds the corresponding A least reliable information bit according to the adaptive coding and modulation mapping table Symbols and their positions; among these symbols, first find the position of the symbols containing two unreliable information bits, assuming that the number of symbols meeting the above conditions is B, then the remaining symbols only contain one unreliable information bit, a total of A-B *2; select the least reliable (A-B*2) / 2 symbols from the remaining A-B*2 symbols, wh...

example 2

[0051] Assume that transmitter 1 adopts the low-order modulation method QPSK, the code rate is 3 / 4, and the spectral efficiency is 1.5bps / Hz (according to this encoding method, it is assumed that there are C symbols including two information bits, and D symbols only include one information bit ), then the receiver 2 calculates the value of the log likelihood ratio of each information bit according to the MAP decoding, and sorts the absolute values ​​of these values.

[0052] Acquisition unit 22 determines the least reliable information bit equal to the threshold value A according to the given retransmission information bit threshold value A; finds the symbols corresponding to these unreliable information bits and their symbols according to the adaptive coding and modulation mapping table. position; in these symbols, first find the symbol position containing two unreliable information bits, assuming that the number of symbols meeting the above conditions is B, then the remaining...

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Abstract

The invention provides a method, a system and a device for enhancing reliability and validity of HARQ and reducing bandwidth required by feedback information simultaneously. The method comprises the following steps: data which is sent from a transmitting end is demodulated and decoded by a receiving end; if an error is detected in the data sent from the transmitting end, the receiving end feeds back symbol position information that includes symbols with unreliable information bit to the transmitting end according to the distribution characteristics of the information bit in the symbols; the transmitting end obtains corresponding unreliable information bit in the data sent by the transmitting end according to the symbol position information which is fed back by the receiving end and the distribution characteristics of the information bit in the symbols, and retransmits the unreliable information bit.

Description

technical field [0001] The invention relates to the technical field of communication, in particular to a hybrid automatic retransmission method, a transmitter, a receiver and a communication system. Background technique [0002] At present, there are three basic error control methods to realize the reliable transmission of data communication, FEC, ARQ and their combination hybrid ARQ. Among them, hybrid ARQ has the best reliability and throughput performance. Hybrid ARQ can be divided into three categories, HARQ-I, HARQ-II, and HARQ-III. [0003] Type I (Chase Merge - Chase Merge) appends a CRC (Cyclic Redundancy Check) and encodes data with FEC. The receiver performs FEC decoding and checks the data packet, if there is an error, it retransmits the data packet, the error packet is discarded, and the same FEC code as the first transmission is still used when retransmitting. This is HARQ at the software level, with transmission control at the RLC (Radio Link Control). [0...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L1/18H04L1/16H04L1/00
Inventor 刘芳佘小明陈岚
Owner NTT DOCOMO INC
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