Buffer-aided relaying improves both throughput and end-to-end delay

Abstract

Buffer-aided relaying has recently attracted a lot of attention due to the improvement in the system throughput. However, a side effect usually deemed is that buffering at relay nodes results in the increase of packet delays. In this paper, we study the effect of buffering at relays on the end-to-end delay of users' data, from the time they arrive at the source until delivery to the destination. We use simple discussions to provide an insight on the overall waiting time of the packets in the system, taking into account the queue dynamics both in the source and relay. We analyze the endto-end delay in the relay networks with Bernoulli data arrivals and channel conditions and prove that the data packets experience lower average end-to-end delay in the buffer-aided relaying system compared with the conventional one. Moreover, using intuitive generalizations, we conclude that the use of buffers at relays improves not only throughput but ironically the average end-to-end packet delay. Through extensive simulations, we validate our analytical results for the system when the data arrival and channel condition processes follow Bernoulli distribution. Furthermore, via the simulations under the settings of practical systems, we confirm our intuition for the general scenarios.

Performance Modeling and Analysis of BASUR-CARQ Protocol Based on Interrelay Interference Cancellation

“…Thus, buffer-aided relays were proposed to adaptively select transmission links at each time slot based on channel state information (CSI) and the number of buffers, which provided significant performance gains [3,4]. Hajipour et al [5] showed that buffer-aided relay led to higher system throughput and lower average end-to-end packet delay. In CC systems, at least two time slots are required to complete the transmission, resulting in a halving of the end-to-end rate.…”

Stochastic Buffer-Aided Relay-Assisted MEC

“…Moreover, it is important to provide a framework which will give directions for investigating the next developments and the more sophisticated scenarios with different constraints. Hence, similar to [15]- [17], [20], we consider a three-node network as a building block of hierarchical time-slotted MMEC systems. It is composed of a source, a buffer-aided server-enabled relay, and another serverenabled node with a level higher than the level of the relay in the hierarchy, where the relay randomly decides to assign a received task to its own computing server or to offload the task to the next node.…”

“…For both cases, improvement in the throughput was observed. In [17], it was shown that bufferaided relaying improves not only the throughput, but also the end-to-end delay. In fact, when considering the whole picture and taking into account the queuing delay at the source, it is revealed that the increase in system throughput leads to lower latency since the data arrival at the source until the reception at the destination.…”