Hybrid Transceiver Optimization for Multi-Hop Communications

TL;DR

This paper proposes a robust hybrid transceiver design for multi-hop MIMO communication systems, optimizing analog and digital components separately under channel errors, leading to improved performance.

Contribution

It introduces a matrix-monotonic optimization framework for robust hybrid transceiver design in multi-hop MIMO systems considering channel errors, simplifying joint optimization.

Findings

Proposed hybrid transceiver outperforms existing solutions.

Separation of analog and digital optimization is effective.

Projection algorithm efficiently optimizes analog transceivers.

Abstract

Multi-hop communication with the aid of large-scale antenna arrays will play a vital role in future emergence communication systems. In this paper, we investigate amplify-and-forward based and multiple-input multiple-output assisted multi-hop communication, in which all nodes employ hybrid transceivers. Moreover, channel errors are taken into account in our hybrid transceiver design. Based on the matrix-monotonic optimization framework, the optimal structures of the robust hybrid transceivers are derived. By utilizing these optimal structures, the optimizations of analog transceivers and digital transceivers can be separated without loss of optimality. This fact greatly simplifies the joint optimization of analog and digital transceivers. Since the optimization of analog transceivers under unit-modulus constraints is non-convex, a projection type algorithm is proposed for analog transceiver optimization to overcome this difficulty. Based on the derived analog transceivers, the optimal digital transceivers can then be derived using matrix-monotonic optimization. Numeral results obtained demonstrate the performance advantages of the proposed hybrid transceiver designs over other existing solutions.