Scaling Law of Multi-Hop Cognitive Network with a Novel Hybrid Access Scheme

The scaling laws for the throughputs of cognitive network with transmission power of secondary users being constrained are studied. The primary nodes and secondary nodes are randomly and uniformly distributed over the same unit square, with density of n and m (n > m). In this paper, we propose a new hybrid access scheme of multi-hop cognitive network, with primary users and secondary users using TDMA scheme and CDMA scheme respectively. It is shown that primary network achieves the same throughput scaling as that in the case when both primary and secondary network adopts TDMA scheme. Meanwhile, we demonstrate that the upper bound of secondary per- node throughput increases with node density m, in contrast to the decreasing pernode throughput in the existing research, which shows that our scheme not only guarantees primary network but also improves the performance of secondary network.