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On the Interplay Between Deadline-Constrained
Traffic and the Number of Allowed Retransmissions
in Random Access Networks
Nikolaos Nomikos, Senior Member, IEEE, Themistoklis Charalambous, Senior Member, IEEE,
Yvonne-Anne Pignolet, Nikolaos Pappas, Senior Member, IEEE
Abstract—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, packet transmission from the queue experi-
ences delays and 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. Towards
understanding the trade-off between reliability and delays that
might lead to packet drops due to the deadline-constrained bursty
traffic with retransmissions, a scenario of a wireless network
utilizing a slotted-ALOHA random-access channel is investigated.
The main focus is to reveal and investigate further the trade-off
between the number of retransmissions and the packet deadline
as a function of the arrival rate. Hence, we are able to determine
numerically the optimal probability of transmissions and number
of retransmissions, given the packet arrival rate and the packet
deadline. The analysis of the system was done by means of
discrete-time Markov chains. Two scenarios are studied: i) the
collision channel model (in which a receiver can decode only
when a single packet is transmitted), and ii) the case for which
receivers have multi-packet reception capabilities. A performance
evaluation for a user with different transmit probability and
number of retransmissions is conducted, demonstrating their
impact on the average drop rate and throughput, while at the
same time showing that there exists a set of values, under which
improved performance can be acquired.
Index Terms—Deadline-constrained traffic, packet deadlines,
queueing, multi-packet reception, discrete-time Markov chains,
delay-sensitive communications, low-latency communications.
I. INTRODUCTION
Future wireless communication networks are envisioned to
play a major role towards enabling autonomous systems in the
context of the Internet of Things (IoT), comprising connected
vehicles, smart devices, or fully automated factories; see,
Preliminary results of this work appeared in [1]. In this paper, we extend
[1] to include the case of multi-packet reception.
N. Nomikos is with the Department of Port Management and Shipping,
National and Kapodistrian University of Athens, 34400 Euboea, Greece (e-
mail: nomikosn@pms.uoa.gr).
T. Charalambous is with the Department of Electrical and Computer
Engineering, School of Engineering, University of Cyprus, Nicosia, Cyprus
(e-mail: charalambous.themistoklis@ucy.ac.cy). He is also with the De-
partment of Electrical Engineering and Automation, School of Electri-
cal Engineering, Aalto University, Espoo, Finland (e-mail: themistok-
lis.charalambous@aalto.fi).
Y.-A. Pignolet is with Dfinity Foundation, Zurich, Switzerland (e-mail:
yvonneanne@pignolet.ch).
N. Pappas is with the Department of Computer and Information Science,
Linköping University, Linköping, Sweden (e-mail: nikolaos.pappas@liu.se).
for example, [2]–[5]. The data traffic produced from these
wireless devices, referred to as machine-to-machine (M2M)
communication, will significantly differ from the wireless traf-
fic served by currently deployed wireless networks. In greater
detail, wireless devices might transmit packets consisting of
few bytes of information, while being sporadically active.
Moreover, a massive number of devices may demand ubiq-
uitous connectivity, and transmitting packets with extremely
stringent latency and reliability requirements, as it is the case
of mission critical M2M applications, supporting real-time
closed-loop control, one of the essential mechanisms enabling
such emerging applications [6]–[8].
The rapid blooming of applications requiring deadline-
constrained packet transmissions and multimedia broadcasting
over wireless communication networks stimulated research
on deadline-constrained broadcasting, relying on scheduling
[9]–[12] and random access [13]–[17]. The work in [13]
obtained the optimal access probability of secondary nodes in
a cognitive radio network towards maximizing the successful
delivery probability (SDP) under specific deadline constraints
using simple slotted-ALOHA. The issue of improving the
reliability for the deadline-constrained one-hop broadcasting,
based on the slotted-ALOHA with retransmission was inves-
tigated in [14]. More specifically, the SDP was derived, as
well as the optimal access probability for SDP maximization.
Regarding retransmissions, their optimal value under specific
throughput requirements was determined. Queuing analysis of
deadline-constrained broadcasting, but without retransmission
was investigated in [15]. By modeling the system as a discrete-
time Geo/Geo/1 queue with a specific delivery deadline,
several performance metrics were investigated, including the
loss probability, queue length distribution, mean waiting time,
and SDP. Nevertheless, the analysis of deadline-constrained
broadcasting with retransmissions has not been analyzed yet.
Furthermore, the paper in [16] studied a slotted-ALOHA
network consisting of nodes with energy harvesting capa-
bilities. For this setup, the author proposed an approximate
analytical model for deriving the timely-delivery ratio, since
the interaction of energy and data queues poses significant
difficulties in obtaining an exact analytical model. Finally,
the author in [17] adopted exploration for multi-channel
ALOHA through preambles before transmitting data packets
in machine-type communication (MTC), showing a maximum
throughput improvement by a factor of 2−e−1≈1.632.
Also, a steady-state analysis with fast retrial was performed,
arXiv:2210.02673v1 [cs.IT] 6 Oct 2022