Research On Distributed MAC Protocol Based On The Joint Design Of Channel Reservation And Cooperative Relay

A growing number of mobile devices such as smart phones and laptops are extensively spreading among the people,and the mobile data traffic continues to proliferate for a wide variety of multimedia applications such as video conference,social applications and virtual reality,hence the wireless communication technology has been developed rapidly,and supporting for massive user volume,ultra-high throughput and ultra-low delay has became the goal of the future wireless networks.The distributed wireless networks,as an important part of future wireless networks,have drawn considerable attention in recent years,and how to design high-performance medium access control(MAC)protocols to improve the network performance has became the focus of distributed wireless networks research.In order to effectively solve both the problem of "the interference between different wireless communication links" and the problem of "the stability of a wireless communication link" in the MAC protocol design,the new idea of combining channel reservation and cooperative relay is proposed,which opens up a new way of designing high-performance distributed MAC protocols.The work and contributions in the dissertation can be summarized as follows:1.An enhanced channel reservation method with rate adaptation has been proposed,and the corresponding area capacity of homogeneous wireless networks has been analysed,then a distributed MAC protocol based on the enhanced channel reservation has been designed.The basic channel reservation scheme can combat the interference by controlling the size of reservation zone.The enhanced channel reservation scheme improves the basic channel reservation by introducing the rate adaptation scheme,and can jointly adapt the reservation zone and data rate to balance the interference mitigation and spatial reuse,then achieves the improved network performance.The concept of area capacity has been proposed based on the classical definition of network capacity,and the analytical model of enhanced channel reservation has been established to optimize the area capacity.For the distributed wireless networks,a distributed MAC protocol based on the enhanced channel reservation has been designed.The simulation results validate the correctness of the theoretical results,and show that the enhanced channel reservation can decrease the reservation zone size and improve the spatial reuse and area capacity.Compared with the dynamical adaptation of carrier sensing threshod and the ideal rate adaptation with fixed carrier sensing threshold,the proposed enhanced channel reservation MAC prototol has achieved an area throughput gain of 110% and 125% respectively.2.A joint channel reservation and cooperative relay method has been proposed,and the corresponding area capacity of homogeneous wireless networks has been analysed,then an ALOHA-based joint reservation and cooperative MAC protocol has been proposed for distributed wireless networks.In order to solve the problem of "interference between different wireless communication links" and the problem of "stability of the wireless communication link" simultaneously,the joint reservation and cooperation scheme has been proposed by combining the enhanced channel reservation and cooperative relay effectively.The area capacity has been derived by modeling the wireless network with the new concept of reserved cooperative link,and it can be optimized by selecting the optimal helper node and employing the optimal reservation zone size.To validate the effectiveness of the joint channel reservation and cooperative relay method,the joint reservation and cooperative MAC protocol based on the ALOHA protocol has been proposed.The simulation results validate the correctness of the theoretical results,and show that an improve spatial reuse and network throughput can be achieved.Compared with the reservation-only and cooperation-only MAC,the proposed joint reservation and cooperation MAC prototol has achieved an area throughput gain of 130% and 250% respectively.3.A joint reservation and cooperative MAC protocol for the next generation WLAN has been designed,and the corresponding network throughput has been analysed by establishing the Markov model.Aiming at the ultra-high throughput requirement in the next generation WLAN,the joint reservation and cooperative MAC protocol has been designed to improve the Trigger Frame for Random access(TF-R)based distributed random access method in the IEEE 802.11 ax draft specification version 1.0.The relationship between the throughput and the impacting factors,such as the number of TF-R,the number of Resource Unit(RU),the number of node,the reservation step,and the frame error rate,has been derived by the RU-based Markov model.The simulation results validate the correctness of the theoretical results,and show its effectiveness of the throughput improvement for the edge nodes.Compared with the reservation-only and cooperation-only MAC,the proposed joint reservation and cooperation MAC prototol has achieved an area throughput gain of 130% and 180% respectively.