In this paper we consider the mutual exclusion problem on a multiple access channel. Mutual exclusion is one of the fundamental problems in distributed computing. In the classic version of this problem, n processes perform a concurrent program which occasionally triggers some of them to use shared resources, such as memory, communication channel, device, etc. The goal is to design a distributed...

This dissertation discusses some techniques to improve the medium access control in infrastructure multi channel wireless local area networks. Medium Access Control protocols (MAC) coordinate the stations and resolve the channel contentions so that scarce radio resources are shared fairly and efficiently amongst participating users. We propose different models to improve the medium access contr...

Ad Hoc and Mesh networks are good samples of multi agent systems, where their nodes access the channel through carrier sense multiple access method, while a node channel access influence the access of neighbor nodes to the channel. Hence, game theory is a strong tool for studying this kind of networks. Carrier sense multiple access parameters such as minimum and maximum size of contention windo...

Multi-Channel Access has the potential to solve the throughput and scalability issues that mar the performance of 802.11 mesh and adhoc networks. It allows multiple simultaneous transmissions in a radio neighborhood thereby increasing network throughput and scalability. In spite of this potential, it is limited to simulation studies and its implementation on hardware is rare. In this demo, we d...

Unlike in overlay cognitive radio networks, secondary users (SUs) in underlay cognitive radio networks can access licensed spectrum even at the presence of a primary user (PU), given that the interference caused by the secondary transmission is lower than a pre-specified threshold. Based on this underlay access principle, we propose in this paper a dynamic channel access strategy for multi-chan...

We consider a cognitive network with a primary and a secondary channel. Primary users have higher priority on the usage of the primary channel, and secondary users are allowed to opportunistically access the primary channel at times when the channel is not occupied by primary users. The secondary channel is dedicated only to secondary users. An analytical model is presented to obtain the perfor...

We study a deterministic approximation of the two-user multiple access wiretap channel. This approximation enables results beyond the recently shown 2 3 secure degrees of freedom (s.d.o.f.) for the Gaussian multiple access channel. While the s.d.o.f. were obtained by real interference alignment, our approach uses signal-scale alignment. We show an achievable scheme which is independent of the r...

In the user identification (UI) scheme for a multiple-access fading channel based on randomly generated (0, 1, -1)-signature code, previous studies used signature code over noisy adder channel, and only state information (USI) was decoded by decoder. However, considering communication model as compressed sensing process, it is possible to estimate coefficients while identifying users. this stud...

A multiple access protocol that is particularly suitable for cellular Internet access and satellite-based networks with on-board processing is developed in this paper. The basic idea is that when a user wishes to send a message, it transmits with a probability paccess that depends on the load on the channel. Under conditions of low load, the probability paccess approaches 1, while at high load ...