Method of hybrid automatic request for retransmission

Abstract

The invention discloses a method for retransmitting a hybrid automatic request. Four constellation diagrams are defined in the method to form a rearranging HARQ technology based on a 256-QAM constellation diagram. The method comprises the following steps that: a) the first constellation diagram is defined as a standard constellation diagram, and the rearrangement of significance bit for other constellation diagrams based on the first constellation diagram is performed; b) data is mapped to the first constellation diagram to modulate and transmit, after a binary random bit stream generated by an information source is scrambled and coded by a transmitting terminal; c) a receiving terminal passes through an inverse process of step b), decodes and judges the data after modulation, when the data is correct, the data is descrambled and transmitted to an information sink; when the data is incorrect, NACK is transmitted to the transmitting terminal, and the data is mapped to the second constellation diagram, and so on, the data is mapped to the third constellation diagram and the fourth constellation diagram for the modulation and transmission in the third time and the fourth time; when the transmitting terminal receives the NACK for the fourth time, the data is mapped to the first constellation diagram once more for the modulation and the transmission, thereby finishing the circulation.

Description

technical field The invention relates to a hybrid automatic retransmission method in the communication field, in particular to a hybrid automatic retransmission method for constellation diagram rearrangement. Background technique The usual method used in communication systems with unreliable and time-varying channel conditions is based on automatic repeat request (ARQ) mode combined with feedforward error correction (FEC) technology, called hybrid automatic repeat request (HARQ) Methods. In order to improve transmission efficiency and transmission quality in time-varying fading channels, many technical standards and proposals including 3GPP and 3GPP2 have adopted Hybrid Automatic Repeat Request (HARQ) technology. HARQ based on Turbo codes and high-order modulation (such as 16-QAM and 64-QAM, 256-QAM) is one of the key technologies for improving system capacity and quality in future mobile communications. HARQ is divided into three types: Type-I; Type-II; Type-III: The en...

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Problems solved by technology

i 1 and i 2 The maximum difference in average reliability can be up to 9 times (i 3 , i 4 =01), i 1 and i 3 The maximum difference in average reliability can be up to 13 times (i 2 , i 3 , i 4 =110), i 1 and i 4 The maximum difference in average reliability can be up to 15 times (i 2 , i 3 , i 4 =111), so the difference in bit reliability is large, which will have an adverse effect on the subsequent Turbo decoding

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