الفهرس 
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Abstract
Device to Device (D2D) communication is anticipated to be the main part of the fifth generation
(5G) wireless communications because of its advantages. Unlike traditional cellular network, D2D
allows proximity users to communicate directly with each other without routing the data through
a base station. For instance, it improves the cellular network’s performance and spectral efficiency.
But interference issues in D2D communications are typically more complex than conventional
cellular network, especially in the underlay mode. To get the perfect performance of D2D
communications system, different types of interference management techniques are needed. As
well as, they are able to achieve efficient spectrum utilization and energy consumption. This is
done by using different Resource Allocation (RA) schemes in D2D communications. As Energy
Efficiency (EE) maximization is one of the most important necessity to be in line with the
requirements of Fifth-Generation (5G) wireless networks; so, the main aim of this thesis is to
improve the Energy Efficiency (EE) of D2D communications underlaying cellular system.
Firstly, we propose an Adaptive Mesh Size (AMS) algorithm for EE maximization of D2D
communications in the system by considering the uplink time division multiple access (TDMA),
for a single channel containing a number of cellular user (CU) and D2D pairs utilizing uplink
spectrum. Besides, it determines the optimal power values for every D2D user in the cellular
network.
Later, we propose a Resource Allocation using Link Admission (RALA) protocol for underlay
D2D Communication by considering the uplink Frequency Division Multiple Access (FDMA),
where multiple channels are considered and each of them contains a single Cellular User (CU) and
multiple D2D pairs. The main aim of this proposed RALA technique is to improve the total EE of
the overall system. The problem of power allocation and channel assignment is studied in this
technique. This is done with the help of the cuckoo search algorithm that is a way to solve the
optimization problems.
Simulation results demonstrate that the proposed AMS algorithm is efficient to achieve the nearoptimal (maximum) EE of D2D communications. The results also show that the proposed AMS
algorithm outperforms the derivative based algorithm. Furthermore, the results indicate that the
proposed RALA algorithm obtained the optimal values of the transmission power successfully for
both CUs and D2D pairs in the system. In addition to that, it is cleared from the results that RALA
algorithm can allocate the D2D pairs fairly on the available channels, consequently, it is considered
an efficient tool for the channel assignment. Moreover, it achieves a higher system EE compared
to the other techniques such Heuristic Only Uplink (Heuristic-OU), Gale Shapely (GaSaBa),
Heuristic Uplink-Downlink (Heuristic UD-RA) algorithm.