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Method of mixed automatic request of retransmission based on orthogonal frequency division multiplex

An orthogonal frequency division, hybrid automatic technology, applied in the multi-frequency code system, using the return channel for error prevention/detection, etc., can solve the problem that the receiving end cannot decode correctly, the receiving end cannot decode correctly, cannot receive correctly, etc. problem, to achieve the effect of improving retransmission efficiency, system throughput, and frequency utilization.

Inactive Publication Date: 2007-05-09
BEIJING XINWEI TELECOM TECH
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AI Technical Summary

Problems solved by technology

Assume that due to poor wireless channel conditions, parts c and d cannot be received correctly, resulting in the receiving end not being able to decode correctly
The existing HARQ technology retransmits without knowing which data blocks are wrong and the receiving end cannot decode correctly
That is to say, the existing HARQ technology does not care that the cause of incorrect decoding is caused by part c and d (or the error mainly occurs in part c and d), and it cannot take advantage of this effective function when retransmitting. information

Method used

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  • Method of mixed automatic request of retransmission based on orthogonal frequency division multiplex
  • Method of mixed automatic request of retransmission based on orthogonal frequency division multiplex
  • Method of mixed automatic request of retransmission based on orthogonal frequency division multiplex

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Embodiment Construction

[0037] As a representative of multi-carrier transmission technology, the basic principle of Orthogonal Frequency Division Multiplexing OFDM is to decompose the high-speed data stream into parallel data streams through serial-to-parallel conversion, and then modulate them on several sub-carriers accordingly to form a data stream capable of transmitting high-speed data. A parallel transmission system for multiple subcarriers of a stream.

[0038] FIG. 2 shows the correspondence between data transmitted via OFDM and subcarriers.

[0039] The present invention proposes that when the receiving end cannot decode correctly, according to the characteristics of OFDM itself (see details), using the existing technology (such as channel estimation), the receiving end can know that some frequency points have serious problems at a certain moment. decline.

[0040] For example, Fig. 3 shows that severe fading occurs at frequency points fc and fd at a certain moment. Through the feedback, t...

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Abstract

The method includes steps: (1) After orthogonal and frequency-division multiplex process, data are sent from the sending end (SE) to the receiving end (RE); (2) RE receives data, estimates channels, de-modulates, decodes and sends ACK / NACK and the position info of the re-sending data block to SE; (3) SE continues to send the new data after receiving ACK; (4) After receiving NACK, SE ascertains the data block which needs to be re-sent, then accumulates the number of re-sent data blocks. If this number is not larger than the max re-sent number, SE re-sends this data block. Otherwise, SE waives this data block and starts to send the new data of the next frame; (5) after receiving the re-sent data block, RE combines these data with the data received before and decodes them, then feedbacks a info to SE, then repeats steps (3) and (4). The invention raises re-sent efficiency, frequency utility and the system throughput.

Description

technical field [0001] The invention relates to a method for hybrid automatic retransmission in a mobile communication system, in particular to a method for hybrid automatic retransmission based on orthogonal frequency division multiplexing in a mobile communication system. Background technique [0002] In modern mobile communication, data transmission will become the main business type. Data services have extremely high requirements on transmission reliability, but the wireless channel environment is very harsh, and signal energy not only attenuates rapidly with the increase of transmission distance, but also is affected by factors such as multipath fading and Doppler frequency shift. It poses challenges to data transmission, especially high-speed data transmission. In terms of improving the reliability of data transmission, the automatic retransmission request (Automatic-Repeat-reQuest, ARQ) technology has played a huge role. As the name implies, ARQ improves transmissio...

Claims

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Application Information

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IPC IPC(8): H04L1/18H04L27/26
Inventor 郑瑜生路鹏
Owner BEIJING XINWEI TELECOM TECH
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