Parameters of the Сarrier Sense Multiple Access Protocol with Conflicts Resolving at the Physical Layer

Abstract

At present, the global growth of communication needs makes us more efficient in using of the frequency spectrum. The development of communication systems requires an increase of throughputs, but the frequency spectrum is limited, which will not allow to increase the channel width or the number of channels. Assuming that at one frequency there is an opportunity to transmit several mutual interference signals at one time, the problem of the separation of these signals arises. But, complexity of demodulation procedures has significantly increased compared to the classical. It is necessary, therefore, to determine whether this complexity increasing will be justified. To answer this question, it is necessary to find out how the throughput of the random multiple access system increases, where the frequency resource multiple reusing is possible. For research was chosen the carrier sense multiple access protocol, which have become widespread in packet networks for their successful combination of relative simplicity of access algorithms and fairly high efficiency. The purpose of the research is to determine the main characteristics of the various carrier sense multiple access protocols with collision detection and with additional assumption about conflicts resolving at the physical layer. The parameters of the carrier sense multiple access protocols with collision detection and with additional assumption about conflicts resolving at the physical layer are obtained. It is shown that in comparison with the classical protocol, the assumption about paired conflicts resolving at the physical layer gives the significant increasing of the throughput in the communication systems with such access protocols. The comparison results are given. The obtained results allow to confirm the expediency of implementation in demodulators of the perspective receiving devices algorithms of conflicts resolving at the physical layer as being characterized by relatively small complexity.