Resource Allocation and Path Selection Strategies for Cognitive Radio Multihop Networks

The next-generation cellular wireless networks will support high data rates and provide quality of service (QoS) for multimedia applications with increased network capacity. Under limited frequency resources, the conventional approach to increase network capacity is to install more base stations (BSs) to exploit spatial reuse. This solution is not very efficient because the cost of the BS transceiver is quite high. An alterna- tive approach is to employ relay stations (RSs) as intermediate nodes to establish multihop communication paths between mobile hosts and their corresponding BSs. Multihop cellular networks (MCN) can potentially enhance coverage, data rates, QoS performance in terms of call block- ing probability, bit error rate, as well as QoS fairness for different users. A number of different architectures, protocols, and analytical models for MCNs have been proposed in the literature where different system aspects were investigated. This thesis aims to present strategies of re- source allocation (RA) and path selection (PS) for cognitive radio (CR) multi-hop communications over a packet-oriented and bit-interleaved- coded OFDM transmission, employing practical modulation and coding schemes. As a promising technology, cognitive radio can be leveraged by the cellular network to increase the overall spectral efciency by allowing additional users in an already crowded spectrum. Here, we assume that a secondary transmitter (ST) adapt his parameters for transmitting to a secondary receiver (SR) or to a relay, over sections of spectrum owned by licensed or primary users (PUs), without harming the quality of service of the latter. This approach is known as underlay. The performance of the system are evaluated in terms of goodput (GP), which is defined as the number of information bits delivered in error free packets per unit of time. It is able to quantify the trade-off between data rate and link reliability, and it is a more suitable metric to quantify the actual perfor- mance of packet-oriented systems, employing practical modulation and coding schemes, respect to the capacity for example. A generic trans- mitter of the network is able to optimize the GP by a proper selection of the transmission parameters, if the channel state information (CSI) are perfect. In most wireless networks, because of channel estimation errors and channel feedback delay, this CSI will not be perfect there- fore any transmitting node only has outdated and imperfect CSI and the channel prediction and as a consequence, a predicted GP (PGP), will be optimized. GP depends on PER that is not easy to calculate for a multi-carrier system and so will be use kESM technique. From here a Local-RA (L-RA) technique and a Sub-Optimal PS (Sub-PS) strategies are formulated for non-cooperative CR multi-hop communications, ex- ploiting xed decode-and-forward (DF) relay nodes (RNs). With these strategies we are able to reduce the signaling over the feedback channel and the computational complexity, compared to the Optimal-RA with Optimal-PS method, paying a very little reduction of GP. Finally we will evaluate whether the increase of the number of relays corresponds to a performance increase

Proceedings of the 7th International Conference EEDAL 2013 Energy Efficiency in Domestic Appliances and Lighting

This book contains the papers presented at the seventh international conference on Energy Efficiency in Domestic Appliances and Lighting. EEDAL'2013 was organised in Coimbra, Portugal in September 2013. This major international conference, which was previously been staged in Florence 1997, Naples 2000, Turin 2003, London 2006, B2e0r0l9in, Copenhagen 2011 has been very successful in attracting an international community of stakeholders dealing with residential appliances, equipment, metering liagnhdti ng (including manufacturers, retailers, consumers, governments, international organisations aangde ncies, academia and experts) to discuss the progress achieved in technologies, behavioural aspects and poliacineds , the strategies that need to be implemented to further progress this important work. Potential readers who may benefit from this book include researchers, engineers, policymakers, and all those who can influence the design, selection, application, and operation of electrical appliances and lighting.JRC.F.7-Renewables and Energy Efficienc