In this paper, we consider two-hop buffer-aided relay network (TBRN) with half-duplex (HD) decode-and-forward (DF) and fading block channel where source transmits information to destination via relay-assisted link. To overcome the delay challenges caused by packets arrival and scheduling, we investigate random-access (RA) protocol and non-random-access (NRA) protocol on the basis of buffer state information (BSI). And then, the closed-form expressions of average queueing delay (AQD) are derived for RA protocol and NRA protocol. First, we minimize the AQD by satisfying certain quality of service (QoS) such as queueing stability and Markov reward process (MRP) of transmit signal-to-noise ratio (SNR) for RA protocol. Second, the AQD is obtained in closed-form for NRA protocol. Our numerical results show that the AQD for RA protocol outperform the benchmark schemes and the NRA protocol.

在本文中，我们考虑具有半双工 (HD) 解码转发 (DF) 和衰落块信道的两跳缓冲辅助中继网络 (TBRN)，其中源通过中继辅助链路将信息传输到目的地。为了克服数据包到达和调度引起的延迟挑战，我们研究了基于缓冲区状态信息 (BSI) 的随机访问 (RA) 协议和非随机访问 (NRA) 协议。然后推导出RA协议和NRA协议的平均排队延迟(AQD)的闭式表达式。首先，我们通过满足某些服务质量 (QoS) 来最小化 AQD，例如排队稳定性和 RA 协议的传输信噪比 (SNR) 的马尔可夫奖励过程 (MRP)。其次，AQD 是在 NRA 协议的封闭形式中获得的。