On the Interplay between Deadline-Constrained Traffic and the Number of Allowed Retransmissions in Random Access Networks

• Published in: Entropy (Basel, Switzerland) Vol. 26; no. 8; p. 655
• Main Authors: Nomikos, Nikolaos, Charalambous, Themistoklis, Wichman, Risto, Pignolet, Yvonne-Anne, Pappas, Nikolaos
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 30.07.2024; MDPI
• Subjects: Access control; Buffers; Bursty traffic; Code Division Multiple Access; Communications networks; Constraints; deadline-constrained traffic; delay-sensitive communications; Discrete time systems; discrete-time Markov chains; Markov chains; multi-packet reception; Network reliability; packet deadlines; Packet transmission; Performance evaluation; Probability; Queues; queuing; Random access; Simulation; Telecommunication systems; Tradeoffs; Wireless communications; Wireless networks; multi-packet reception; queuing; delay-sensitive communications; low-latency communications; deadline-constrained traffic; packet deadlines; discrete-time Markov chains
• ISSN: 1099-4300; 1099-4300
• DOI: 10.3390/e26080655

In this paper, a network comprising wireless devices equipped with buffers transmitting deadline-constrained data packets over a slotted-ALOHA random-access channel is studied. Although communication protocols facilitating retransmissions increase reliability, a packet awaiting transmission from the queue experiences delays. Thus, packets with time constraints might be dropped before being successfully transmitted, while at the same time causing the queue size of the buffer to increase. To understand the trade-off between reliability and delays that might lead to packet drops due to deadline-constrained bursty traffic with retransmissions, the scenario of a wireless network utilizing a slotted-ALOHA random-access channel is investigated. The main focus is to reveal the trade-off between the number of retransmissions and the packet deadline as a function of the arrival rate. Towards this end, analysis of the system is performed by means of discrete-time Markov chains. Two scenarios are studied: the collision channel model (in which a receiver can decode only when a single packet is transmitted), and the case for which receivers have multi-packet reception capabilities. A performance evaluation for a user with different transmit probabilities and number of retransmissions is conducted. We are able to determine numerically the optimal probability of transmissions and the number of retransmissions, given the packet arrival rate and the packet deadline. Furthermore, we highlight the impact of transmit probability and the number of retransmissions on the average drop rate and throughput.