On the performance of WAR systems with limited number of ISM-band ad hoc relay channels

Coping with congestion or hot spots is one of the common problems faced by the wireless service providers. To handle this hot spot or congestion problem in a cellular network, several dynamic load balancing schemes based on channel borrowing have previously been proposed. A recent approach to dynamic load balancing is the Integrated Cellular and Ad hoc Relay (iCAR) system. iCAR employs ad hoc relay stations (ARS's) in the cellular network to balance traffic loads efficiently and to share channels between cells via primary and secondary relaying. In this paper, it is shown that the realistic performance of ICAR systems in terms of dynamic load balancing and load sharing is heavily dependent upon the number of available ISM-band ARS channels. Results also indicate that the number of ARS channels required for dynamic load balancing is much more than the number of ARS channels required for load sharing (i.e., for bringing the call blocking probability of a hot spot to 2%).