Hop reservation multiple access for multichannel packet radio networks

摘要

A new multicheannel MAC protocol, called Hop Reservation Mutiple Access (HRMA), for packet-radio networks is introduced, specified and analyzed. HRMA is based on slow frequency hopping spread spectrum (FHSS) and takes advantage of the time slotting necessary for frequency hopping. HRMA applies a hop reservation and handshake mechanism on every hop, to guarantee collision-free data transmission in the presence of hidden terminals; this is accomplished by allowing a pair of communicating nodes to reserve a frequency hop (channel). HRMA provides a baseline to offer QoS in ad-hoc networks, based on simple half-duplex slow FHSS radios We analyze the throughput achieved in HRMA for the case of a fully connected network, assuming variable-length packets, and compare it against an ideal multichannel access protocol and the multichannel slotted ALOHA protocol. The numerical results show tat HRMA can achieve much higher throughput than mltichannel slotted ALOHA in the traffic-load ranges of interest, especially when the average packet length is large compared to a slot size in which case the maximum throughput of HRMA is close to what can be obtained with an ideal protocol.