Hopping Strategies for Adaptive FH-CDMA Ad Hoc Networks under External Interference

We discuss the performance of an adaptive FH-CDMA ad hoc network under the influence of external interference where node positions are modeled by a homogeneous Poisson point process. The optimum channel assignment that balances internal network interference due to spatial reuse and external interference is derived analytically for a path loss and Rayleigh fading model. The performances of the resulting hopping strategies are then compared to various suboptimal hopping strategies such as non-adaptive hopping and min-max allocation with constant QoS. It is found that adaptivity offers a benefit only at low to medium node densities and that a good suboptimal strategy can be based on hard exclusion of bad channels (thresholding) with optional min-max allocation to balance the load of active channels.