Precoder Design for Cooperative Cognitive Radio Systems

Cognitive radio (CR) has been an active area of research in wireless communication in recent years. In this thesis, optimal transmission strategies at the source and relay nodes in cooperative underlay CR systems assumption are studied with an aim of achieving maximum possible throughput for the secondary system for two different scenarios: one with multiple secondary relay nodes with a single antenna at each of the source, relay and destination nodes of the secondary system, and the other with a single secondary relay node with multiple antennas at each of the source, relay and destination nodes of the secondary system. In particular, an amplify-and-forward (AF) relaying secondary system is considered that operates in the presence of a primary system. For the first scenario, the joint relay and power allocation problem is studied under power constraints at the source and the relay of the secondary system and the interference constraint from the secondary source and relay to the primary users (PUs). An optimal relay selection and power allocation scheme is first proposed. Since the proposed scheme requires an exhaustive search over all candidate relay nodes, to reduce complexity, a non-exhaustive sub-optimal search method is also proposed with performance near to that of the optimal scheme.In the second scenario, the problem of relay and source precoder design in a multi-antenna non-regenerative relaying CR system is studied assuming underlay spectrum sharing methodology with the PUs. The optimal structure of the relay and source precodering matrices are derived for the cases of dominant power and dominant interference constraints. However, deriving optimal precoding scheme in a more general case is not straightforward, therefore, a sub-optimal structure is proposed when both the power and interference constraints are present. Finally, a novel iterative algorithm is proposed for the joint design of relay and source precoding matrices.Simulation results for different scenarios show that the proposed schemes significantly improve the performance in terms of the achievable throughput.

Name thesis:degree_name

Master of Science in Engineering

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Electrical Engineering

Grantor dc:publisher

University of Akron

Year dc:date

2013

Author dc:creator

• Budhathoki, Krishna Ram

Contributors dc:contributor

• Bahrami, Hamid Reza

• Electrical Engineering
• cognitive radio
• multi-input multi-output (MIMO)
• non-regenerative relaying
• capacity
• precoder design

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=akron1363180310

OAI identifier oai:identifier

oai:etd.ohiolink.edu:akron1363180310