Interference aware resource allocation with QoS guarantees in multiservice OFDMA/SC-FDMA systems

Abstract

With the increasing growth of mobile subscribers all around the world, new technologies should be developed in order to fulfill the demand for higher data rates. Also, a considerable amount of subscribers own smart devices, which are constantly connected to the network, increasing the traffic on mobile networks. In order to provide those users with a good service, some technological improvements should be made. We can cite the development of the Long Term Evolution (LTE)-Advanced standard, which can provide peak data rates of 3 Gbps in the Downlink (DL) and 1.5 Gbps in the Uplink (UL), as one of the leading technologies related to high throughput in mobile networks. In this new scenario, not only it is important to deliver high amounts of data, but also to provide the User Equipments (UEs) with a good service, which can be measured by means of Quality of Service (QoS). Some multiple access schemes like Orthogonal Frequency Division Multiple Access (OFDMA) and Single Carrier - Frequency Division Multiple Access (SC-FDMA) together with multiple antennas techniques like Multiple Input Multiple Output (MIMO) can maintain the QoS at acceptable levels. Another functionality that can be used to improve the system performance is the use of efficient Radio Resource Allocation (RRA) algorithms. Those algorithms are used in order to perform the best possible allocation between the system resources and UEs, in a way that the mobile system can operate in the boundaries of its capacity region. Under the presented conditions, the focus of this thesis is to evaluate the RRA algorithms proposed in (LIMA et al., ; LIMA, 2012), which maximize cellular system total data rate, while satisfying QoS restrictions, in a scenario subject to intercell interference, also facing new restrictions available in real cellular systems, like Resource Block (RB) aggregation for the DL and power adjustment in the UL. Thus, we want to evaluate the Radio Resource Management (RRM) algorithms in a more realistic scenario, as we still want to assure that its main goal will be reached: maximize the system data rate subject to minimum satisfaction constraints per service. We performed the evaluation for the DL using single and multiple antennas schemes, while for the UL we used only the single antenna scheme. As main contributions of this work, we can emphasize modifications in the original Constrained Rate Maximization (CRM) algorithms in order to deal with inter-cell interference, the addition of RB aggregation restriction for the DL and the addition of a more realistic Link Adaptation (LA) and power adjustment in the UL. All those evaluations were performed through computational simulations.