Channel Quality Based Routing Protocol (CQBR)&Realization On MANET Platform

The article is based on the Ad Hoc network theory. Ad Hoc network contains no preset infrastructures as the routers of the network. All the nodes in the network play the same role both as terminal nodes and routers. By the packet transferring among nodes, every destination in the network is reachable. In the real world, such kind of network is often applied in some military scenery where no routers or AP points are included.Based on some formal research of our laboratory, this article begins at the construction of such platform. This job mainly includes two parts, which is the construction of the hardware platform and the software systems. The terminals of our platform maintain such function modules as RFID scanning, GPS, humidity&temperature sensor, video and media applications. Most of such modules are required by the military warehouse management.Such Ad Hoc network platform contains mainly three parts; they are wireless card, operation system kernel and upper application part. The routing protocol is operated in both application mode and kernel mode. These two modes interact with each other tightly. The kernel mode maintains a kernel routing table and the function of kernel routing table searching. Other jobs including route establishment, route maintenance and some other complex functions are reserved in the application mode.Based on numerous tests, to increase the network performance fundamentally, a mechanism to ensure each link quality is required. If only the relative good links can be chosen by the route discovery process, the network quality can be ensured.This article proposes a link quality based routing protocol, in which only the links of relative good signal strength are included for the construction of route to destination. During the route discovery process, only the RREQ packets come from a strong hop which is judged by the comparison of RSSI value and RSSI threshold will be forwarded to next node. Otherwise, RREQs from weak links are discarded directly. By this mechanism, only the strong links are included in the route discovery process.Finally, I realized the channel quality based routing protocol mechanism on our Ad Hoc platform. I designed a representative scenario and test the protocol on the platform and compared with AODV and AODV-BL protocol. In the aspects of route discovery result, network throughput, network packet loss, the like quality based routing protocol performed better than others. So we come to a conclusion that, by the careful link screening, the CQBR improve the network stability and efficiency.