Method for cooperative relay beamforming based on limited feedback

Abstract

A method for cooperative relay beamforming based on limited feedback is applicable to a communication system. The communication system comprises a transmitter, a plurality of relays and a receiver. The transmitter is provided with a plurality of antennae, each relay is provided with a single antenna, the receiver is provided with a plurality of antennae, and the plurality of the relays cooperate and adopt an amplification and forwarding protocol; the whole communication process is finished in two time slots, wherein in the first time sot, after performing transmit beamforming on a data flow, the transmitter broadcasts the data flow to all relays; and in the second time slot, all relays determine distributed beamforming code words according to limited feedback information containing code word indicators and power amplification factors from the receiver and forward receipt signals subjected to respective code word component treatment to a information sink; and the design of a code book is completed by code book design and cord word updating algorithm, the relays select code words which can maximize the instant signal to noise ratio of the receiver from the code book according to each channel condition as a beamforming vector.

Description

technical field [0001] The invention relates to a beam forming method applied to a wireless communication system, in particular to a limited feedback-based cooperative relay beam forming method, which belongs to the field of wireless communication. Background technique [0002] Relay-assisted cellular wireless communication systems have the advantages of extending cell coverage, improving spectrum efficiency of cell edge users, and overcoming shadow fading. In recent years, researchers have studied relay communication from the perspectives of relay protocols, information theory, and processing algorithms. For example, for single-input single-output (SISO) wireless relay communication systems, there are three typical Relay protocols, namely Amplify-and-Forward (AF), Decode-and-Forward (DF) and Compress-and-Forward (CF), where the AF relay protocol does not require decoding Directly forwarding signals, the processing complexity and power consumption are very low, so it is mor...

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Problems solved by technology

[0004] Current research usually assumes that each relay must obtain the ideal Channel State Information (CSI), and then due to the inaccurate channel estimation of the receiver, the time delay of channel information feedback, and noise pollution, this assumption is not valid. The realistic, more practical case is that the relay only knows part of the CSI

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