Signaling System In Wireless Mobile Ad Hoc Networks

In recent years, with the rapid development in computer networks and wireless communications technologies, the Ad hoc mobile wireless network has more and more come to our attention. Especially there are many kinds of real time traffic in Internet nowadays (such as audio and video). Providing QoS(Quality of Service) in Ad hoc networks has become a hotspot of research. But it is very challenging because of the characters of Ad hoc networks, such as, lower bandwidth, rapidly-changing topologies and the interference in the wireless channel, etc. In order to provide better QoS, the thesis researches the signaling system of Ad hoc networks together with routing protocol and data link protocol. Based on MSR(Multipath Source Routing) which is proposed by our research group and implemented based on DSR(Dynamic Source Routing) developed by Carnegie Mellon University, we implement QoS-MSR through extending MSR(Multipath Source Routing) to support QoS routing. Then based on INSIGNIA developed by Columbia University and QoS-MSR, we proposed a new multipath in-band signaling system, M-INSIGNIA. Working with QoS-MSR, M-INSIGNIA realizes MBSR(Multipath Bandwidth Splitting Reservation), under which the overall bandwidth requirement is split to smaller bandwidth requirements among multiple paths. The simulation results show that M-INSIGNIA can improve the reservation packet ratio, packet delivery ratio, and reduce the end-to-end delay. Because of the channel contention at the IEEE802.11 MAC layer, when a node had reserved bandwidth for some QoS flow, the neighborhood nodes may also contend for the channel to transmit their flows simultaneously, thus the reservation can not be guaranteed. Through simulation, we found that the problem does exist. We propose a new Neighborhood Reservation Signaling(NRS) system as a solution. In NRS, when a node reserves bandwidth for a QoS flow, corresponding bandwidth reservation must be done in all its neighborhood nodes simultaneously, which is implemented by controlling the rate of Best Effort packets. Thus the impact on reserved bandwidth caused by channel contention can be eliminated and the reserved bandwidth for the QoS flow can be guaranteed with certainty. Through extensive simulations, we conclude that NRS can provide better QoS support than INSIGNIA. That is NRS improves the reservation packet ratio, packet delivery ratio, and reduces the end-to-end delay.