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A method of automatic retransmission request without error check code

A technology of automatic retransmission request and error check code, applied in the direction of error prevention, transmission system, digital transmission system, etc., to achieve the effect of simple circuit implementation, flexible implementation, and diversity gain

Active Publication Date: 2019-06-14
ZHEJIANG UNIVERSITY OF SCIENCE AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The purpose of the present invention is to overcome the above-mentioned existing ARQ problems under the low average signal-to-noise ratio of wireless fading channels, and propose an automatic retransmission request method without error checking codes, by monitoring channel coefficients and retransmitting based on channel coefficients Request conditions, flexibly improve communication reliability

Method used

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  • A method of automatic retransmission request without error check code
  • A method of automatic retransmission request without error check code
  • A method of automatic retransmission request without error check code

Examples

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example 1

[0042] The examples of the present invention will be described in detail below in conjunction with the accompanying drawings. This example is implemented on the premise of the technical solution of the present invention, and detailed implementation and performance analysis are given, but the protection scope of the present invention is not limited to the following example 1. Include the following steps:

[0043] Step 1: The receiving end sets a channel coefficient threshold, and when the actual channel coefficient is lower than the threshold, the channel is considered unreliable.

[0044] In step 2, the information at the sending end is modulated by binary phase shift keying (BPSK) without channel coding, and sent in units of frame length k=12.

[0045] Step 3, the channel is a Rayleigh fading channel. The receiving end can realize ideal channel estimation and obtain accurate channel coefficient h.

[0046] Step 4, the receiving end compares the channel coefficient amplitud...

example 2

[0068] Example 2 for comparison: no retransmission system.

example 3

[0069] Example 3 for comparison: the information bit length of the traditional ARQ transmitter is k=12, and 4 redundant bits are added after CRC-4 encoding. The receiving end will feed back NAK if the CRC check fails; if the check passes, it will feed back ACK, and perform BPSK demodulation on the received signal.

[0070] Example 4 for comparison: Single-Input-Multiple-Output (SIMO) diversity reception can realize diversity in three ways: time, frequency and space. In time diversity, the same frame information is repeatedly sent L times. Frequency diversity uses L different frequency bands to send the same frame of information simultaneously. Space diversity receives the same frame of information through L antennas. All three perform maximum-ratio combination on signals that receive the same frame of information L times. Under the same total effective signal-to-noise ratio (after diversity combining), the same diversity gain L can be realized in time, frequency and space. ...

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Abstract

The invention discloses an automatic repeat request method needing no error check codes. The method comprises that a receiving end sets an optimum channel coefficient threshold, wherein through adoption of the threshold, an average receiving bit error rate can be minimized; a receiving end estimates a channel; when a channel coefficient amplitude is less than the threshold, the receiving end sends one bit of negative acknowledge (NAK) to the sending end; otherwise, the receiving end does not feed back and expresses acknowledgement; and the sending end sends a next frame or repeat according to the response. According to the method, the sending end does not need the error check codes and channel information; the channel coefficient threshold of the receiving end can be adjusted flexibly; ACK / NAK feedback only needs one bit; the performance of the method is better than the conventional ARQ; diversity reception and sending power control of ideal channel information are realized; and the diversity gain is increased linearly along with effective signal to noise ratio.

Description

technical field [0001] The invention relates to an automatic retransmission request method without an error check code, optimizes the threshold based on the effective signal-to-noise ratio, and is suitable for the technical field of wireless communication. Background technique [0002] Two error control strategies widely used in data communication are Forward Error Control (FEC) and Automatic Repeat Request (ARQ). ARQ improves the reliability of the communication system through error checking and data retransmission. The error checking code commonly used in ARQ in modern communication standards is cyclic redundancy checking code, such as Ethernet, wireless local area network, LTE (Long Term Evolution). ARQ was originally designed for the time-invariant additive Gaussian white noise channel AWGN, and can also be directly applied to wireless fading channels. [0003] The improvement of ARQ reliability depends on the retransmission of detected error frames. It is well known ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L1/16H04L1/18
CPCH04L1/1657H04L1/1806H04L1/1825
Inventor 吴茗蔚甘培润宋天宇
Owner ZHEJIANG UNIVERSITY OF SCIENCE AND TECHNOLOGY