Evaluation of adaptive power control algorithms for a hierarchical packet radio network

Spread spectrum packet radio networks are being proposed to support tactical communications in highly mobile battlefield environments. Direct sequence packet radio waveforms offer certain benefits that provide antijamming (A/J) and LPI protection while reducing the effects of multipath and providing rapid acquisition. However, near/far interference restricts the performance of a direct sequence type waveforms in a tactical network where the relative power of each transmitting node cannot be centrally controlled. This paper reviews the implementation and analysis of adaptive power control for a spread spectrum waveform within a hierarchical packet radio network. The adaptive power control algorithm operates in conjunction with a receiver directed/reservation-based channel access protocol that uses a sequence of short synchronization and acknowledgment bursts to reserve the channel and adapt the transmit power for the exchange of direct sequence modulated data packets. The waveform, channel access protocol and power control algorithm operate within a hierarchical packet radio network that supports 400 or more radio nodes within a Brigade size area of 20/spl times/30 km. The network of radio nodes is divided into clusters that communicate locally. Clusterheads within each cluster form, a virtual backbone for intercluster packet exchange. This paper presents an overview of the waveform, protocols and power control algorithm that support the packet exchange process. Modeling results are presented to show the relative throughput, delay and reliability performance of the network versus various adaptive power control parameters.