Self-Coexistence Strategy in Heterogeneous Cognitive Radio Networks

Different from general cognitive wireless networks, there is no centralized scheduling and management infrastructure among heterogeneous cognitive networks. Multiple cells may operate in the same vicinity resulting in unfair spectrum occupation time (when the cells belong to different industries) and degraded performance of the cellular networks. A distributed self-coexistence mechanism is necessary. In this paper, we take the self-coexistence of multi users in heterogeneous scenarios as the problem of spectrum allocation in non-cooperative mode. Hence we propose Fair Self-Coexistence Strategy (FSCS). In this strategy, not only the fairness of occupation time is considered, but also different competitive priority metric based on Quality of Service (QoS) is adopted. Each cognitive cell independently completes the spectrum allocation process, by use of sensing techniques and perceptual information about neighboring network cells. The simulation experiment results show that our spectrum allocation strategy guarantees the fairness among the heterogeneous secondary networks. And in the resource scarce environment, our strategy can effectively achieve the differentiation competition results.

Self-Coexistence Among Cognitive Radio Networks Using Risk-Motivated Channel Selection Based Deference Structure

Among cognitive radio networks there is a persistent trend of competition to acquire under-utilized and idle channels for data transmission. The competition for spectrum resources often results in the misuse of the spectrum resources as networks experience contention in attempt to access unoccupied spectrum bands. The competitive scenario causes cognitive radio networks to incur a huge amount of loss, which constitutes a major problem of self-coexistence among networks. As a way to minimize these losses we present a self-coexistence mechanism that allows cognitive radio networks to coexist with each other by implementing a risk-motivated channel selection based on deference structure. Cognitive radio networks form deference structure community to have more efficient access to a channel of interest and can defer transmission to one another on that channel, thereby minimizing the chances of conflicts. As part of the decision making process to become a member of a deference structure community, cognitive radio networks rely on a risk-motivated channel selection scheme to evaluate the tentative deference structure channel. We provide numerical and simulation results that demonstrates the benefits of the proposed self-coexistence mechanism and show how it helps networks to coordinate their spectrum activities, minimize contention experienced and improve their utility. We also emphasize on the importance of the deference structure community size with regards to the average performance of member networks.