Effective capacity Maximization in Two Way Half-Duplex Relays with Finite Blocklength Codes

Short packet transmission is one of the topics considered in the new generation of telecommunication systems for low latency connections. In this paper, in order to have a low latency communication, a cooperative system with finite block length (FBL) transmission is investigated. In this relay system, a two-way half-duplex (HD) relay replaces data packets between two nodes. The two-way relay functionality is assumed as amplify-and-forward (AF) with fixed gain and variable gains. Due to the importance of delay, the criterion for evaluating system performance is the effective capacity. Therefore, to optimize the performance of the system, the optimal power allocation is used to maximize the effective capacity. The concavity of this power allocation problem under the assumption of constant total available power between nodes and relay is calculated. Finally, the effect of various parameters including packet length, bit error rate and quality-of-service (QoS) is investigated on overall system performance.