الفهرس 
Chapter 1 : IntroductionOnly 14 pages are availabe for public view
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Abstract
The past few years have seen a major change in cellular networks, as explosive growth
in data demands requires more and more network capacity and backhaul capability. New
wireless technologies have been proposed to tackle these challenges. One of the emerging
technologies is device-to-device (D2D) communications. It enables two cellular user
equipments (UEs) in proximity to communicate with each other directly and they use the
same cellular radio resources. In this case, D2D is able to offload data traffic from central
base stations (BSs) and significantly improve the spectrum efficiency of a cellular network,
and thus is one of the key technologies for the next generation cellular systems.
This thesis presents a proposed resource and power allocation scheme for device-todevice
(D2D) communications in an interference limited area overlaying cellular networks.
The proposed scheme is implemented in two sequential steps. The first step depends on
implementing a vital algorithm that guarantees fairness in resource allocation among different
D2D pairs by allocating the best subcarriers for every user such that every link’s data rate
requirements can be satisfied. The second step utilizes the water-filling algorithm for power
allocation among the subcarriers allocated to a certain link, which allocates high amount of
power to the subcarriers with the high channel gain but it allocates low amount of power to
the subcarriers with low channel gain.
The simulation results in this thesis are divided into three sections, in order to study the
effect of our algorithm on different directions. The first simulation section is dedicated to
study the effect of our algorithm on fairness of the system with changing the number of D2D
pairs. The second simulation section is for studying the effect of the proposed algorithm on
the system fairness while we change the coherence bandwidth. The third section of the
simulation is about studying the effect of the proposed algorithm on the fairness and the
spectral efficiency with changing the signal to noise ratio.
Finally, the proposed scheme achieves high fairness with acceptable performance
compared to rival algorithms in the literature. The simulation results show that the proposed
algorithm iterative fairness optimization resource allocation scheme (iterative FORA)
outperforms the best subcarrier channel state information resource allocation scheme and the
subcarrier achievable data rate scheme in terms of Jain’s fairness index.