Research On Precoding Technique For Wireless Relay System

With the arrival of mobile Internet era, wireless communication systems need to provide people with wider network coverage, higher reliability, and greater system capacity. The characteristics of Multi antenna for MIMO relay technology can be more efficient to play the characteristics of the space gain relay station, to cope with the current growth needs of mobile communication traffic. Meanwhile,precoding technology can improve the performance of the relay MIMO system.This paper focuses on the precoding technique for wireless relay system. The following content are the main efforts of this paper:1. Investigate on system model and performance characteristics of relay technology and MIMO technology. The core system technical indicators like the capacity for the relay MIMO systems are calculated. At the same time, Summarizes the current mainstream precoding technology,and discusses the limited feedback precoding technique deeply.2. A method of precoding technology for the single antenna multiple relay system is proposed. Using to build the power allocation diagonal matrix and codebook matrix, and using limited feedback to obtain the equivalent channel matrix of the relay system in the case of getting the imperfect channel state information. This paper reduces the channel feedback bits and uses the vector quantization method to establish the codebook matrix. The simulation results show that this method can improve the system capacity and suppress the BER of the whole communication process effectively.3. A joint precoding technology is proposed aiming at the multi-source and multi-destination nodes MIMO relay system. At the same time, a channel estimation matrix QR feedback mechanism is introduced in for the relay nodes and destination nodes channel. The Lagrange function and KKT condition are given under the condition of power constraint. For the design of system precoding matrix as the goal of maximizing the system capacity. Finally, the performance of MMSE-QRG system in capacity is verified by the simulation platform.