Reliable open spectrum communications through proactive spectrum access

Abstract

Abstract-Open Spectrum systems offer an attractive solution to the reuse of under-utilized licensed spectrum. Existing proposals take a reactive sense-and-avoid approach to impulsively reconfigure spectrum usage without any knowledge of future dynamics. We propose a proactive spectrum access approach where secondary users utilize past observations to build predictive models on spectrum availability, and intelligently plan channel usage to maximize utilization and minimize disruptions to primary users. Based on the characteristics of TV-broadcast, we develop a simple availability metric and apply a usability filter to eliminate unreliable channels with heavy and frequent appearance of primary users. Our experimental results show that the proactive approach can significantly reduce the number of disruptions. We also observe a clear tradeoff between the disruption rate and the throughput at secondary users. By varying the usability filter threshold, we can control this tradeoff according to the constraints of primary users and the application requirements at secondary users.

Improving Data Dissemination in Multi-hop Cognitive Radio Ad-Hoc Networks

“…Recently, a lot of work has been carried out for dynamic channel management in cognitive radio networks [3,4,5,15,20,25,26]. However, all these approaches focuses on single-hop cognitive radio networks and either requires the presence of any central entity or coordination with primary radio nodes in their channel selection decision.…”

“…An approach that use non-continuous unoccupied band to create a high throughput link is discussed in [4]. In [5], authors proposed a proactive channel selection strategy for TVbroadcast networks, which is single-hop and requires strong co-ordination with TV receivers in their channel selection decision.…”

“…A lot of works have been carried out for dynamic channel management in CRNs. These approaches focus on single-hop CRNs [2,3,4,5], the presence of central entity, or the coordination with PR nodes in their channel selection decision. A proposal/solution related to our approach is Selective Broadcasting (SB) [6], however, SB requires more than one transceiver, resulting in bigger and more complex devices, as for military applications [7].…”

Predictive Channel Access in Cognitive Radio Networks Based on Variable Order Markov Models

“…The second drawback is the processing complexity of the base station being high. In [18] the authors assume that secondary users coordinate with each other using a low power ultra-wide-band channel as in the underlay networks.…”

“…Further more these units are capable of operating on Ultra Wide Band mode for short periods of time for the exchange of control information. A similar assumption is taken in [18]. We adopt a listen before talk policy for the secondary users.…”