Buffer-Aided Two-Way Relaying with Lattice Codes

Abstract

The achievable sum-rate of the two-way relaying becomes far below the cut-set outer bound if the signal-to-noise-ratio (SNR) from one node to the relay is significantly different from the SNR from the other node to the relay, and particularly so for decode-and-forward or compute-and-forward type relaying. In this paper, we propose a buffer-aided compute-and-forward two-way relaying with lattice codes to improve the sum-rate in asymmetric SNR two-way relay channels (TWRCs). Specifically, the relay can store some amount of data received in the multiple access phase before forwarding it, thereby controlling the amount of data to be transmitted to each direction in the broadcast phase. Simulation results show that the sum-rate can be improved with the use of buffers compared to the conventional two-way relaying without buffers.