Time-Frequency Coupled Proportional Fair Scheduler with Multicarrier Awareness for LTE Downlink

Abstract-Proportional fair schedulers have been thoroughly used in Long Term Evolution (LTE) due to their ability to provide a good trade-off between cell spectral efficiency and user fairness. Current algorithms provide suboptimum solutions at a low computational cost, but present several drawbacks. This paper proposes a Coupled and Multicarrier Aware PFS (CMA-PFS) for LTE downlink that increases efficiency as compared with current algorithms with independent time and frequency domain scheduling, referred to as Decoupled PFS (D-PFS). The proposed algorithm includes new features such as tight coupling between time and frequency domain scheduling and multicarrier transmission awareness. Simulations have been conducted using an International Mobile Telecommunications Advanced (IMT-Advanced) compliant semi-static simulator. Results show that the CMA-PFS improves proportional fairness as compared with D-PFS that is reflected both in an increase of cell spectral efficiency (around +2%) and a higher cell-edge user spectral efficiency (around +10%) in a Single User MIMO (SU-MIMO) system

Proyecto Investigador: Adaptación de tasa binaria y planificación de usuarios dependiente del canal radio en el estándar LTE (Long-Term Evolution)

Este Proyecto Investigador se presenta como parte de la documentación requerida para el Concurso de Acceso a plazas de cuerpos docentes universitarios. Centro: E.T.S.I. de Telecomunicación. Cuerpo: Profesores Titulares de Universidad. Departamento: Señales, Sistemas y Radiocomunicaciones (0935). Área de conocimiento: Teoría de la Señal y Comunicaciones (800). Perfil docente: Radiocomunicaciones; Comunicaciones Móviles. Perfil investigador: Tecnología de las Telecomunicaciones (3325). Dedicación: Complet

Fairness-Oriented and QoS-Aware Radio Resource Management in OFDMA Packet Radio Networks: Practical Algorithms and System Performance

During the last two decades, wireless technologies have demonstrated their importance in people’s personal communications but also as one of the fundamental drivers of economic growth, first in the form of cellular networks (2G, 3G and beyond) and more recently in terms of wireless computer networks (e.g. Wi-Fi,) and wireless Internet connectivity. Currently, the development of new packet radio systems is evolving, most notably in terms of 3GPP Long Term Evolution (LTE) and LTE-Advanced, in order to utilize the available radio spectrum as efficiently as possible. Therefore, advanced radio resource management (RRM) techniques have an important role in current and emerging future mobile networks. In all wireless systems, the data throughput and the average data delay performance, especially in case of best effort services, are greatly degraded when the traffic-load in the system is high. This is because the radio resources (time, frequency and space) are shared by multiple users. Another big problem is that the transmission performance can vary heavily between different users, since the channel state greatly depends on the communication environment and changes therein. To solve these challenges, new major technology innovations are needed. This thesis considers new practical fairness-oriented and quality-of-service (QoS) -aware RRM algorithms in OFDMA-based packet radio networks. Moreover, using UTRAN LTE radio network as application example, we focus on analyzing and enhancing the system-level performance by utilizing state-of-the-art waveform and radio link developments combined with advanced radio resource management methods. The presented solutions as part of RRM framework consist of efficient packet scheduling, link adaptation, power control, admission control and retransmission mechanisms. More specifically, several novel packet scheduling algorithms are proposed and analyzed to address these challenges. This dissertation deals specifically with the problems of QoS provisioning and fair radio resource distribution among users with limited channel feedback, admission and power control in best effort and video streaming type traffic scenarios, and the resulting system-level performance. The work and developments are practically-oriented taking aspects like finite channel state information (CSI), reporting delays and retransmissions into account. Consequently, the multi-user diversity gain with opportunistic frequency domain packet scheduling (FDPS) is further explored in spatial domain by taking the multiantenna techniques and spatial division multiplexing functionalities into account. Validation and analysis of the proposed solutions is performed through extensive system level simulations modeling the behavior and operation of a complete multiuser cell in the overall network. Based on the obtained performance results, it is confirmed that greatly improved fairness can be fairly easily built in to the scheduling algorithm and other RRM mechanisms without considerably degrading e.g. the average cell throughput. Moreover, effective QoS-provisioning framework in video streaming type traffic scenarios demonstrate the effectiveness of the presented solutions as increased system capacity measured in terms of the number of users or parallel streaming services supported simultaneously by the network