Cross layer design of cognitive radio systems

Abstract

It is a well known fact that Spectrum is an important tool for efficient as well as effective communication and it is always available only in scarcity Cognitive radio is an important technology which aims to improve the spectrum resource utilization in an efficient way A cognitive radio transceiver is used to detect and sense spectrum holes without causing interference to the primary users PUs The recent development of cognitive radio technology and the concept of cognitive radio ad hoc networks CRAHNs have been proposed in the literature with the aim of applying the cognitive radio to traditional ad hoc networks This new network paradigm creates more research challenges than those in classical cognitive radio networks CRNs In this work the proposed research themes and associated research issues surrounding cognitive radio ad hoc networks have been dispensed with The analytical and experimental results have been carefully studied and the justification has been made In this dissertation we consider cognitive radio ad hoc networks CRAHNs with the following issues i Expanding Network coverage ii Increasing the capacity iii Maximizing the throughput iv Increasing the spectrum efficiency and v Increasing the spectral efficiency The solution for this is Relay Node The load on source node can be minimized by putting the work to relay nodes in the Cognitive Radio Ad Hoc Networks While extending the network coverage the indigence for the use of more relay nodes becomes necessary When several relay nodes come into existence then a need arises to select the best one among them Now the challenge arises when the non cooperation exists between the relay nodes When non cooperation exists first of all it is necessary to bring in the cooperation among relay nodes and to establish the same Game theory is used here The concepts of cooperation games and non Co operation games are used and the maximum payoff is achieved By using the game theory the cooperation is established The performance comparison between the cooperation and the non cooperation mode has been done By using the Nash Equilibrium Markov process Ergodic process and Markov perfect Nash Equilibrium concepts the non cooperation between relay nodes are converted into cooperation among the relay nodes The networks of queues are also analysed The networks of queues are considered as Jackson Networks and the results for M bar M bar one and M bar D bar one are noted It is necessary to proceed towards finding the desired results like Expanding Network coverage Increasing the capacity Maximizing the throughput Increasing the spectrum efficiency and Increasing the spectral efficiency Reducing energy consumption is the most important design consideration for such networks Hence the purpose of cross layer CRAHNS is used and it conveys the desired outcomes In this thesis the cross layer design has considered from the application point of view Since all layers of the protocol stack contribute to the energy per bit consumed in its end to end transmission energy minimization requires a joint design across all the layers as well as incorporating the underlying hardware characteristics In this thesis we proceed from a single relay node to a number of ten relay nodes that are considered For the first example we begin with a point to point link where we indicate that dramatic energy savings is possible when the trade off between the transmission time number of nodes and packet size distribution The results will clearly show case the cross layer design is a preferred method to minimize total energy consumption And then we move toward to investigate cooperation between nodes to further reduce energy consumption Game theory is used to establish the co operation among relay nodes Use of Femto cells Smart Antennas Hybrid Networks the various possible optimizations of cross layer designs has been indicated for further research