Buffer-Aided Multi-Hop DF Cooperative Networks: A State-Clustering Based Approach

This paper analyzes the performance of a buffer-aided multi-hop relaying system using the max-link relay selection scheme for decode-and-forward cooperative networks. A Markov chain approach is adopted to analyze the state transition matrix that models the evolution of the status of relay buffers. Analytical expressions for the steady-state probability vector are obtained for a three-hop buffer-aided system, and through these expressions, we observe that states with the same probabilities can be clustered, thus reducing the size of the state transition matrix. We propose a state-clustering-based method to obtain the reduced state transition matrix, which is further used to derive an analytical expression for the outage probability with reduced computational complexity. The method is general in the sense that it does not require any prior knowledge about the steady-state probability vector and the state transition matrix. Furthermore, we illustrate, in detail, the construction of the reduced state transition matrix and the related steady-state distribution by an example. An analytical expression for the average packet delay is also derived. Both analytical and simulation results are provided to investigate the performance of buffer-aided multi-hop relaying networks.