Robust wave beam molding method based on distributed bidirectional relay system

Abstract

The invention discloses a robust wave beam molding method based on a distributed bidirectional relay system. The system consists of two user nodes and a plurality of bidirectional relay nodes distributed at different positions, wherein all nodes are respectively provided with a single antenna. Two users complete information exchange within two time intervals through a relay, which is shown in an attached map. Considering that a relay node is a non-ideal signal channel, the invention proposes a robust wave beam molding optimization scheme which takes the maximization of the expectation weight and mean square error of a received signal as the objective, takes the mean transmission total power of all relay nodes as the constraint. Because an objective function in an optimization problem has no precise analysis mode, the method solves the lower limit of the objective function through the approximation in a large signal to noise ratio section and a Jensen inequation, and obtains the approximate expression of the lower limit through a one-order Taylor series expansion, and enables a non-convex optimization problem to be gradually changed into a convex problem which is easy to solve. Finally, the method obtains the closed-form solution of a robust wave beam vector through matrix substitution and decomposition.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, and in particular relates to a robust beamforming method based on a distributed two-way relay system. Background technique [0002] In recent years, two-way relay communication system has received extensive attention from industry and academia. The system uses self-interference cancellation technology and physical layer network coding technology, so that users at both ends can transmit information through relay nodes within two time slots. Compared with the traditional one-way relay system, its spectrum efficiency is improved. This also makes it considered an important part of future heterogeneous wireless communication networks. [0003] In order to further improve the link reliability, diversity characteristics, and cell throughput of the two-way relay system, and considering the size and power consumption characteristics of the relay node, the industry proposes a single-antenna...

AI Technical Summary

Problems solved by technology

However, due to the complex form of the robust beamforming optimization problem, it is very difficult to solve the optimization problem, and usually requires an iterative algorithm for numerical solution. It is even more difficult to obtain the closed-form solution for the robust beamforming scheme, and the closed-form solution for Exploring the internal structure and mechanism of beamforming vectors has important guiding significance

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