الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Cognitive Radio (CR) is a technology which can solve the scarcity and inefficient of spectrum
usage. It achieves this target by enabling the primary users and cognitive users share the same
spectrum under the condition that the cognitive user must minimize the power interference pro-
duced on the primary user through using multiple antennas for the transmitters and receivers.
Thus, this thesis introduces the interference management problem for underlay spectrum shar-
ing approach of the MIMO cognitive and primary users. This study has been introduced for
two different cases: single unlicensed users and multiple unlicensed users. In case of sin-
gle unlicensed user, the interference management problem of a CR networks has proposed for
minimizing the interference power introduced to the licensed receiver while satisfying capacity
and power constraints for unlicensed user transmission. A solution for the interference man-
agement problem of a single primary user and cognitive user in MIMO system is proposed.
The problem was formulated as interference minimization problem under both transmission
capacity and transmit power constraints for obtaining a closed form solution. Low complexity
algorithm is proposed for designing the optimal covariance matrix based on the Lagrangian
duality method which convey the cost function and its constraints into a weighted sum form.
Numerical results are performed to corroborate our theoretical results, where a near optimal
capacity and interference power are achieved with a low complexity. This study has been
extended for multiple cognitive users where the competition over the utility maximization be-
tween the secondary transmitters is occurred. This problem has been modeled as a cooperative
and non-cooperative game where game theory is an effective mathematical tools for analyzing
the confliction between secondary transmitters to achieve the optimal behavior derived algo-
rithm. Numerical results approved the effectiveness of the cooperative scenario that minimizes
the network interference power. Thesis organized as following:
• Chapter(2):Concept of the Cognitive Radio
This chapter introduces overview about the spectrum limitation and inefficient spectrum
usage problem as a result to a strategy of static spectrum allocation and proposed a CR
as a solution for this problem. Different spectrum access approaches of a CR networks
are clarified where the underlay approach is a basic of this study.
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• Chapter(3): Interference Minimization with Power-Capacity Constraints for Cognitive
Radio Networks
The interference management problem is studied for MIMO CR networks. The scenario
of the conflicting problem consists of single primary user coexist with single cognitive
user on a same frequency band where cognitive user try to balance between minimizing
the interference which produced on licensed primary user and maximizing the transmis-
sion capacity.
• Chapter(4): Game theoretic approaches for Interference Management in MIMO Cogni-
tive Radio Networks
Network interference management (NIM) problem is studied from game-theoretic point
of view with the aim to minimize overall network interference in case of multi-cognitive
users MIMO CR network. Non-cooperative and cooperative solution are proposed.
• Chapter(5): Simulation Results
In this chapter, the numerical results are performed to corroborate our theoretical results.
The numerical results for a two different cases single cognitive user and multiple cogni-
tive users are introduced and discussed.
• Chapter(6): Conclusion and Future work
This chapter summarized thesis and predict the possible direction of the future researches.