CSMA/CA with Beam Forming Antennas in Multi-hop Packet Radio
Marvin Sánchez, Tim R. Giles, Jens Zander · 2001
Low cost, reliable and easily deployed ad hoc rural-area wireless networks are needed for both civilian and military communications. In order to fulfill the requirement of easy deployment the network needs to be autonomous, self-organising and self-healing. Multi-hop Packet Radio Networks are a suitable solution to fulfill this requirement. In this type of network all nodes use the same frequency for transmission as well as using a store and forward procedure which enables communications between nodes that are out of direct radio range. There are a variety of multiple access protocols applicable to this type of system. Spatial Time Division Multiple Access (STDMA) has been studied and found to be efficient and fair, the draw-back is that it may not offer good peak rates for bursty data traffic. The Carrier Sense Multiple Access/ Collision Avoidance (CSMA/CA) protocol promises high efficiency and the ability to provide high peak data rates. Although CSMA/CA is not new there is very little work one considering the rural-area multi-hop environment. This paper presents the analysis of CSMA/CA in the rural-area multi-hop environment with and without adaptive antennas. An explanation of the system design with adaptive antennas is given as well as simulation results showing the expected performance gain.