Cognitive network

About: Cognitive network is a research topic. Over the lifetime, 4213 publications have been published within this topic receiving 107093 citations.

Joint Compressive Sensing in Wideband Cognitive Networks

Abstract: In this paper, a distributed compressive spectrum sensing scheme in wideband cognitive radio networks is discussed. An AIC RF front-end sampling structure is proposed requiring only low rate ADCs and few storage units for spectrum sampling. Multiple CRs collect compressed samples through AICs and recover spectrum jointly. A novel joint sparsity model is defined in this scenario, along with a universal recovery algorithm based on S-OMP. Numerical simulations show this algorithm outperforms current existing algorithms under this model and works competently under other existing models.

Outage behaviour of cooperative underlay cognitive networks with inaccurate channel estimation

Abstract: In spite of the importance of channel information availability in system design optimization, it is almost impossible to obtain exact channel information with existing channel estimators. Therefore, investigating the effect of inaccurate channel estimation on the performance behaviour of cooperative underlay cognitive networks becomes essential. This paper is devoted to the derivation of an exact closed-form expression for the outage probability of such networks. This expression is subsequently employed in evaluating numerically the corresponding outage performance and it is demonstrated that the analytical results are in excellent agreement with the respective results from computer simulations. It is also shown that the channel estimation error degrades dramatically the performance of unlicensed networks.

Open Research issues in Cognitive Radio

Abstract: Cognitive Radios have been receiving increasing attention in academia, industry, and government. This has come after several studies indicating that up to 90% of the allocated radio spectrum less than 3GHz is idle most of the time (1). As a result, spectrum regulation around the world is in progress to allow unlicensed access on a non-interfering (2) (3). Current researches are investigating different techniques of using cognitive radio to reuse more locally unused spectrums to increase the total system capacity. However, there are many issues across all layers of a cognitive radio system design. In this paper we address cognitive radio issues for enabling cognitive radio including more spectrums sensing, protocol, hardware, security and algorithmic challenges that could limit their performance or even make them infeasible. We also give some insight into the evolution of cognitive radios and characteristics. We conclude

Study of Relay Selection in a Multi-Cell Cognitive Network

Abstract: This paper studies best relay selection in a multi-cell cognitive network with amplify-and-forward (AF) relays. We derive the analytical integral-form expression of the cumulative distribution function (CDF) for the received signal-to-noise-plus-interference-ratio (SINR) at the destination node, based on which the closed-form of the outage probability is obtained. Analysis shows that the proposed relay selection scheme achieves the best SINR at the destination node with interference to the primary user being limited by a pre-defined level. Simulation results are also presented to verify the analysis. The proposed relay selection approach is an attractive way to obtain diversity gain in a multi-cell cognitive network.

Development and performance of cellular automaton model of OSI network layer of packet-switching networks

Abstract: We present a cellular automaton model of the OSI network layer. Our focus is on parameters that can affect flow and congestion in the network, such as randomly inserted additional links, used to model additional wired and wireless connections in LANs and WANs. We present selected simulation results and observe, in accordance with other models, that throughput is maximal at the critical load of the network. Further, the addition of links increases the critical load of a network if queueing costs are taken into account in routing decisions for packets.