Massey Documents by Type

Permanent URI for this communityhttps://mro.massey.ac.nz/handle/10179/294

Browse

Has files: YesSubject: search.filters.subject.Cell phone systems

Search Results

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Clustering algorithm for D2D communication in next generation cellular networks : thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Engineering, Massey University, Auckland, New Zealand
    (Massey University, 2021) Aslam, Saad
    Next generation cellular networks will support many complex services for smartphones, vehicles, and other devices. To accommodate such services, cellular networks need to go beyond the capabilities of their previous generations. Device-to-Device communication (D2D) is a key technology that can help fulfil some of the requirements of future networks. The telecommunication industry expects a significant increase in the density of mobile devices which puts more pressure on centralized schemes and poses risk in terms of outages, poor spectral efficiencies, and low data rates. Recent studies have shown that a large part of the cellular traffic pertains to sharing popular contents. This highlights the need for decentralized and distributive approaches to managing multimedia traffic. Content-sharing via D2D clustered networks has emerged as a popular approach for alleviating the burden on the cellular network. Different studies have established that D2D communication in clusters can improve spectral and energy efficiency, achieve low latency while increasing the capacity of the network. To achieve effective content-sharing among users, appropriate clustering strategies are required. Therefore, the aim is to design and compare clustering approaches for D2D communication targeting content-sharing applications. Currently, most of researched and implemented clustering schemes are centralized or predominantly dependent on Evolved Node B (eNB). This thesis proposes a distributed architecture that supports clustering approaches to incorporate multimedia traffic. A content-sharing network is presented where some D2D User Equipment (DUE) function as content distributors for nearby devices. Two promising techniques are utilized, namely, Content-Centric Networking and Network Virtualization, to propose a distributed architecture, that supports efficient content delivery. We propose to use clustering at the user level for content-distribution. A weighted multi-factor clustering algorithm is proposed for grouping the DUEs sharing a common interest. Various performance parameters such as energy consumption, area spectral efficiency, and throughput have been considered for evaluating the proposed algorithm. The effect of number of clusters on the performance parameters is also discussed. The proposed algorithm has been further modified to allow for a trade-off between fairness and other performance parameters. A comprehensive simulation study is presented that demonstrates that the proposed clustering algorithm is more flexible and outperforms several well-known and state-of-the-art algorithms. The clustering process is subsequently evaluated from an individual user’s perspective for further performance improvement. We believe that some users, sharing common interests, are better off with the eNB rather than being in the clusters. We utilize machine learning algorithms namely, Deep Neural Network, Random Forest, and Support Vector Machine, to identify the users that are better served by the eNB and form clusters for the rest of the users. This proposed user segregation scheme can be used in conjunction with most clustering algorithms including the proposed multi-factor scheme. A comprehensive simulation study demonstrates that with such novel user segregation, the performance of individual users, as well as the whole network, can be significantly improved for throughput, energy consumption, and fairness.
  • Thumbnail Image
    Item
    Effective relaying mechanisms in future device to device communication : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in School of Food and Advanced Technology at Massey University, Palmerston North, New Zealand
    (Massey University, 2020) Zaidi, Syeda Kanwal
    Future wireless networks embrace a large number of assorted network-enabled devices such as mobile phones, sensor nodes, drones, smart gears, etc., with different applications and purpose, but they all share one common characteristic which is the dependence on strong network connectivity. Growing demand of internet-connected devices and data applications is burdensome for the currently deployed cellular wireless networks. For this reason, future networks are likely to embrace cutting-edge technological advancements in network infrastructure such as, small cells, device-to-device communication, non-orthogonal multiple access scheme (NOMA), multiple-input-multiple out, etc., to increase spectral efficiency, improve network coverage, and reduce network latency. Individual devices acquire network connectivity by accessing radio resources in orthogonal manner which limits spectrum utilisation resulting in data congestion and latency in dense cellular networks. NOMA is a prominent scheme in which multiple users are paired together and access radio resources by slicing the power domain. While several research works study power control mechanisms by base station to communicate with NOMA users, it is equally important to maintain distinction between the users in uplink communication. Furthermore, these users in a NOMA pair are able to perform cooperative relaying where one device assists another device in a NOMA pair to increase signal diversity. However, the benefits of using a NOMA pair in improving network coverage is still overlooked. With a varierty of cellular connected devices, use of NOMA is studied on devices with similar channel characteristics and the need of adopting NOMA for aerial devices has not been investigated. Therefore, this research establishes a novel mechanism to offer distinction in uplink communication for NOMA pair, a relaying scheme to extend the coverage of a base station by utilising NOMA pair and a ranking scheme for ground and aerial devices to access radio resources by NOMA.
  • Thumbnail Image
    Item
    Multi-carrier cooperative wireless communication : performance analysis and resource allocation : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Electrical Engineering at Massey University, New Zealand
    (Massey University, 2013) Abrar, Muhammad
    Relay-based cooperative wireless communication is emerging as the major candidate technology for the next generation wireless cellular networks that will support significantly higher data rates than the recent systems. The combination of cooperative relaying with Orthogonal Frequency Division Multiplexing (OFDM) is a very promising design for next generation of wireless networks with increased system throughput and spectral efficiency. The success of this combination, like other wireless networks, relies on the efficient utilization of limited radio resources such as relays, power, subcarriers and antennas. In this research, resource allocation problems are examined with different relaying techniques and protocols and computationally efficient resource allocation algorithms are proposed. The general objective is to device resource allocation schemes in relay-based cellular networks that maximize the system throughput under different constraints. The main goal of our research is to develop efficient resource allocation algorithms for two different relaying models, namely; one-way relaying and two-way relaying in realistic scenarios for the Third Generation Partnership Project (3GPP) Long Term Evolution Advanced (LTE-Advanced) cellular standard. Performance of the proposed algorithms will be evaluated in terms of not only the throughput but also the computational complexity. In particular, in this thesis we present low-complexity efficient schemes for jointly deciding the selection of relays and subcarriers for the users. Two types of fairness among users, namely; minimum rate proportional fairness and access proportional fairness, are also considered in assigning subcarriers to users in relay networks. A new low-complexity iterative resource block (RB)-pairing and allocation algorithm is also investigated in relay networks. Finally, we present a brief analysis of inter-cell interference in relay networks. Both theoretical analysis and computer simulations are performed in the performance evaluation of the proposed algorithms. Furthermore, practical implementation issues are also addressed.