Generalized Buffer-State-Based Relay Selection for Fixed-Rate Buffer-Aided Cooperative Systems

In this paper, we propose a generalized buffer-state-based relaying protocol in the context of finite buffer-aided cooperative systems. More specifically, the proposed relaying scheme relies on two concepts: the simultaneous activation of multiple source-to-relay links; and buffer-state-based relay selection for packet transmission and reception. In order to avoid buffer overflow as well as an empty buffer at the relay nodes, we introduce a novel thresholding scheme that gives priority to link selection. As a result, the proposed scheme is capable of achieving a lower outage probability and a lower end-to-end packet delay than existing buffer-aided relaying protocols. Our simulation results demonstrate the explicit performance advantage of the proposed scheme over conventional schemes, especially for a scenario of a high number of relay nodes.