# Achievable Rates of Buffer-Aided Full-Duplex Gaussian Relay Channels

## TL;DR

This paper derives closed-form achievable rate expressions for buffer-aided full-duplex MIMO Gaussian relay channels, analyzing residual self-interference effects and optimal transmission strategies for different RSI dynamics.

## Contribution

It provides the first analytical expressions for achievable rates in buffer-aided FD MIMO relay channels considering residual self-interference.

## Key findings

- Residual self-interference can be eliminated in slow-RSI with buffering.
- Fast-RSI cannot be fully eliminated, affecting achievable rates.
- Optimal transmission strategies are derived for maximizing throughput.

## Abstract

We derive closed-form expressions for the achievable rates of a buffer-aided full-duplex (FD) multiple-input multiple-output (MIMO) Gaussian relay channel. The FD relay still suffers from residual self-interference (RSI) after the application of self-interference mitigation techniques. We investigate both cases of a slow-RSI channel where the RSI is fixed over the entire codeword, and a fast-RSI channel where the RSI changes from one symbol duration to another within the codeword. We show that the RSI can be completely eliminated in the slow-RSI case when the FD relay is equipped with a buffer while the fast RSI cannot be eliminated. For the fixed-rate data transmission scenario, we derive the optimal transmission strategy that should be adopted by the source node and relay node to maximize the system throughput. We verify our analytical findings through simulations.