Resource allocation techniques for downlink Non-Orthogonal Multiple Access-Based 5G wireless systems
The expected usage growth of smart devices in the wireless cellular system and many connected devices with other new, improved technological advancement has resulted in the high data rate demands and spectrum scarcity problems. Hence, efficient resource allocation techniques are required to im...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2021
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/97851/1/FK%202021%2092%20UPMIR.pdf http://psasir.upm.edu.my/id/eprint/97851/ |
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| Summary: | The expected usage growth of smart devices in the wireless cellular system and
many connected devices with other new, improved technological advancement has
resulted in the high data rate demands and spectrum scarcity problems. Hence,
efficient resource allocation techniques are required to improve spectrum
utilization and address the high data rate demands for future wireless
communication networks. Non-Orthogonal Multiple Access (NOMA) is one of the
most promising multiple access technology for fifth-generation (5G) and future
advancement due to its significant role in achieving high spectral efficiency and
energy efficiency together with supporting large number of connectivity required
for massive machine-type communication (mMTC). This thesis’s main objective is
to solve the downlink NOMA systems’ resource allocation problems for improving
the system sum rate and energy efficiency. The study addressed the optimization of
resources in a single-cell and heterogeneous transmission systems using convex
optimization techniques. First, the downlink NOMA-based single-cell systems’
resource allocation problems are addressed. The closed-form solutions are derived
using Karush-Kuhn-Tucker (KKT) conditions to maximize the system sum rate and
the Dinkelbach (DKL) algorithm to maximize system energy efficiency. Moreover,
the Hungarian (HNG) algorithm is utilized for pairing two users into the sub-channel. For 10 users, 2 W Base Station (BS) power, the system sum rate of the
proposed NOMA with optimal power allocation using KKT conditions and HNG
(NOMA-PKKT-HNG) achieves a higher sum rate by 20.02 %, 40.09 %, and
50.32 % than NOMA with a Difference of Convex programming (NOMA-DC),
NOMA with Fractional Transmitting Power Allocation (NOMA-FTPA), and
conventional Orthogonal Frequency Division Multiple Access (OFDMA)
techniques respectively. Besides, with 20 users at the BS, the system energy
efficiency presented an optimal power allocation using DKL and HNG
(NOMA-PDKL-HNG) with greater performance than those from NOMA-DC, NOMA-FTPA and OFDMA by 40 %, 59 %, and 86 % respectively. Second, the
downlink NOMA’s resource allocation problems in a heterogeneous network
(NOMA-HetNets) are investigated. The results show that the femtocell user’s
minimum energy efficiency by applying NOMA with power allocation method
using Sequential Convex Programming and user pairing based on Greedy
Algorithm (NOMA-SCP-GA) is higher by 38.22 %, 58.84 %, and 76.39 %
compared to NOMA-DC, NOMA-FTPA, and OFDMA methods respectively. The
obtained results from both NOMA scenarios confirm that the proposed
NOMA-PKKT-HNG, NOMA-PDKL-HNG, and NOMA-SCP-GA methods are
promising approaches for the 5G capability demands. |
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