We investigate the problems of route lifetime maximization and interference to primary user minimization jointly in outage constrained stationary cognitive radio ad hoc networks. It may be noted that although, both lifetime maximization schemes in wireless ad hoc networks (WANETs) and interference minimization schemes in cognitive radio networks mostly aim to minimize transmission power of nodes in a given routing session, using any one of them to achieve both of the said objectives simultaneously does not yield satisfactory performance. In this paper, first, we study both minimum total interference (MTI) and maximum lifetime (ML) routing problems separately as joint power allocation and routing problems. Next closed form expressions for power allocation for both MTI and ML strategies are derived and, from these solutions, we obtain corresponding routing metrics to solve the routing problems. Moreover, closed form expression for a hybrid-ML-MTI power allocation approach is also proposed followed by a new hybrid routing metric. We also present implementation issues related to the proposed hybrid routing and power allocation scheme. Extensive simulation results are used to evaluate performance of our proposed schemes both in regular grid and random networks. Results show that while in grid networks, a straightforward combination of MTI routing with ML power allocation scheme strikes a good balance between interference and lifetime performances, in random networks, our proposed hybrid approach is found to extend lifetime and control interference performances simultaneously in a significant manner.
