No abstract

This paper develops a solution for the problem of uncorrelated user selection in mobile cognitive radio ad hoc networks, with the objective to increase the performance of cooperative spectrum sensing. For this, a fully distributed user selection algorithm is developed by adaptively selecting uncorrelated cognitive radio users, which is able to account for dynamic changes in the network topology and in the channel conditions. Since the proposed user selection is based on the evaluation of the correlation experienced by the cognitive radio users, it is mandatory to have a parameter able to measure the correlation among them. For this, a spatial correlation coefficient is proposed to express the correlation characteristics of mobile cognitive radio users in different environments. Performance evaluation is conducted through simulations, and the results reveal the benefits of adopting the proposed correlation-aware user selection for cooperative spectrum sensing

No abstract

No abstract

Abstract-Two main issues affect the existing routing metrics for cognitive radio ad hoc networks: i) they are often based on heuristics, and thus they have not been proved to be optimal; ii) they do not account for the route diversity effects, and thus they are not able to measure the actual cost of a route. In this paper, an optimal routing metric for cognitive radio ad hoc networks, referred to as OPERA, is proposed. OPERA is designed to achieve two features: i) Optimality: OPERA is optimal when combined with both Dijkstra and Bellman-Ford based routing protocols; ii) Accuracy: OPERA exploits the route diversity provided by the intermediate nodes to measure the actual end-to-end delay, by taking explicitly into account the unique characteristics of cognitive radio networks. A closedform expression of the proposed routing metric is analytically derived for both static and mobile networks, and its optimality is proved rigorously. Performance evaluation is conducted through simulations, and the results reveal the benefits of adopting the proposed routing metric for cognitive radio ad hoc networks.

The paper proposes a Distributed Hash Table (DHT)-based multi-path routing protocol for scalable ad hoc networks. Specifically, we propose a multipath-based improvement to a recently proposed DHT-based shortest-path routing protocol, namely the Dynamic Address RouTing (DART). The resulting protocol, referred to as multi-path DART (M-DART), guarantees multi-path forwarding without introducing any additional communication or coordination overhead with respect to DART. The performances of M-DART have been evaluated by means of numerical simulations across a wide range of environments and workloads. The results show that M-DART performs the best or at least comparable with respect to widely adopted routing protocols in all the considered scenarios. Moreover, unlike these protocols, it is able to assure satisfactory performances for large networks by reducing the packet loss by up to 75%.

No abstract

Widely linear structures for multiuser detection of code division multiple-access signals are proposed, which jointly elaborate the received signal and its complex conjugate. Computer simulations show that the new structures significantly outperform the conventional linear ones, in terms of suppression capability of both wideband multiple-access and narrowband interference