23 research outputs found
Wireless Network-Level Partial Relay Cooperation: A Stable Throughput Analysis
In this work, we study the benefit of partial relay cooperation. We consider
a two-node system consisting of one source and one relay node transmitting
information to a common destination. The source and the relay have external
traffic and in addition, the relay is equipped with a flow controller to
regulate the incoming traffic from the source node. The cooperation is
performed at the network level. A collision channel with erasures is
considered. We provide an exact characterization of the stability region of the
system and we also prove that the system with partial cooperation is always
better or at least equal to the system without the flow controller.Comment: Submitted for journal publication. arXiv admin note: text overlap
with arXiv:1502.0113
Learning to be energy-efficient in cooperative networks
Cooperative communication has great potential to improve the transmit diversity in multiple users environments. To achieve a high network-wide energy-efficient performance, this letter poses the relay selection problem of cooperative communication as a noncooperative automata game considering nodes’ selfishness, proving that it is an ordinal game (OPG), and presents a game-theoretic analysis to address the benefit equilibrium decision-making issue in relay selection. A stochastic learning-based relay selection algorithm is proposed for transmitters to learn a Nash-equilibrium strategy in a distributed manner. We prove through theoretical and numerical analysis that the proposed algorithm is guaranteed to converge to a Nash equilibrium state, where the resulting cooperative network is energy-efficient and reliable. The strength of the proposed algorithm is also confirmed through comparative simulations in terms of energy benefit and fairness performances
Buffer-aided 5G cooperative networks: Considering the source delay
© 2019 Association for Computing Machinery. Applying relays employed with data buffers drastically enhance the performance of cooperative networks. However, lengthening the packet delay is still a serious challenge for cooperative networks. This paper thoroughly studies a new factor affecting the packet delay which is the source delay. This factor plays a key role in calculating the total delay that messages encounter before reaching their destination. This delay is crucial especially in applications that require their messages to get transmitted as fast as possible. Markov chain is employed to model the system and analyze the source delay. Numerical simulations verify the analytical model, the results show that buffer-aided relays can beat non-buffer relays in terms of average packet delay, especially at low signal to noise ratio (SNR) range. This makes adding buffers to relays an attractive solution for the packet delay in 5G applications
Analysis of Half-Duplex Two-Node Slotted ALOHA Network With Asynchronous Traffic
Despite the long history of research on slotted ALOHA, the exact analysis of
the average delay is still in question as the performance of each node is
coupled with the activity of other nodes. In this paper, we consider a network
comprised of two half-duplex transmitter nodes with asynchronous arrival
traffic that follow the slotted ALOHA protocol. We propose a new queueing
theoretic model based on the state-dependent queues to analyze the network. In
addition, we derive the exact values of delay and stability region for each
node. The numerical results demonstrate the accuracy of our proposed model.Comment: 5 pages, 5 figure
On the Benefits of Network-Level Cooperation in Millimeter-Wave Communications
Relaying techniques for millimeter-wave wireless networks represent a
powerful solution for improving the transmission performance. In this work, we
quantify the benefits in terms of delay and throughput for a random-access
multi-user millimeter-wave wireless network, assisted by a full-duplex network
cooperative relay. The relay is equipped with a queue for which we analyze the
performance characteristics (e.g., arrival rate, service rate, average size,
and stability condition). Moreover, we study two possible transmission schemes:
fully directional and broadcast. In the former, the source nodes transmit a
packet either to the relay or to the destination by using narrow beams,
whereas, in the latter, the nodes transmit to both the destination and the
relay in the same timeslot by using a wider beam, but with lower beamforming
gain. In our analysis, we also take into account the beam alignment phase that
occurs every time a transmitter node changes the destination node. We show how
the beam alignment duration, as well as position and number of transmitting
nodes, significantly affect the network performance. Moreover, we illustrate
the optimal transmission scheme (i.e., broadcast or fully directional) for
several system parameters and show that a fully directional transmission is not
always beneficial, but, in some scenarios, broadcasting and relaying can
improve the performance in terms of throughput and delay.Comment: arXiv admin note: text overlap with arXiv:1804.0945