Loughborough University Institutional Repository
نویسنده
چکیده
The explosive growth of wireless applications and high demand for wireless resources have created spectruIIl crisis. Many spectrnm occupancy measurements have shown that most of the allocated spectrum experiences inefficient utilization. Hence radically new approaches arc required for better utilization of spectrum. This has motivated the concept of opportunistic spectrum access in the licensed bands namely cogni ti ve radio technology. This intelligent wireless system has the potential to improve the spectrum utilization by enabling unlicensed users to access the licensed bands without disturbing the licensed users. In this thesis, spatial multiplexing techniques are studied for underlay cognitive radio networks where transmit beamformers arc designed to satisfy quality of service and interference constraints using convex optimization techniques. Robust schemes arc also proposed in the presence of imperfect channel state information at the basestation. To overcome the infeasibility issues encountered in the beamformer design, a joint resource allocation and admission control technique is proposed using the branch and bound optimi7,ation method. Finally, signal-to-interference and noise ratio (SINR) balancing techniques are developed for different types of interference constraints on the primary users using a max-min fairness approach. These SINR balancing techniques also solve the problem of infeasibility. The performance of all these new schemes has been verified using MATLAB simulation results. I dedicate this thesis to my parents.
منابع مشابه
Loughborough University Institutional Repository
Al(OH)(3) facilitated synthesis of water-soluble, magnetic, radiolabelled and uorescent hydroxyapatite nanoparticles This item was submitted to Loughborough University's Institutional Repository by the/an author.restricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Please cite the published version.
متن کاملSystem Dynamics Based Learning Environments: a Technology for Decision Support and Assessment
This item was submitted to Loughborough University's Institutional Repository by the/an author. Citation: QUDRAT-ULLAH, H., 2006. System dynamics based learning environments: a technology for decision support and assessment. IN: Danson, M. (ed.). 10th CAA International Computer Assisted Assessment Conference : Proceedings of the Conference on 4th and 5th July 2006 at Loughborough University. Lo...
متن کاملCar Seat and Occupant Modelling Using Cad
This item was submitted to Loughborough University's Institutional Repository by the/an author. Citation: CASE, K., XIAO, D-C. and PORTER, J.M., 1995. Car seat and occupant modelling using CAD. IN: Stockton, D. and Wainwright, C. (eds.) Advances In Manufacturing Technology IX: Proceedings Of The 11th National Conference On Manufacturing Research, De Montfort University, Leicester, UK, 12-14 Sep...
متن کاملLoughborough University Institutional Repository
A list of requirements for a genetic programming representation is put forward and a representation separating the genotype and phenotype with a linear genome is presented. The target language for the genetic program is Perl. The mapping process, between the genotype and phenotype, converts blocks of four genes into program statements. This process is context-free and therefore provides inherit...
متن کاملLoughborough University Institutional Repository Maintaining control
Controller failures degrade a control system pedormance. In this paper, a novel main fenonce approach for controllerfailures is proposed f o restore fhe degraded peformance of the controller. The method is fo equivolenfly shifr any foulf occurring in a controller to the plant. Eased on the assumed process model, a compensafor with a serial link is designed to nlainfain the faulty controller in ...
متن کامل