Packet Scheduling for LTE-Advanced

University of Technology, Sydney. Faculty of Engineering and Information Technology.LTE-Advanced has been approved by the International Telecommunication Union (ITU) as a 4G mobile communication system. It is also called IMT-Advanced or true 4G technology. LTE-Advanced is an evolution of LTE (Release-8) and backward compatible with LTE because they both use the same air-interface technologies such as OFDMA, MIMO, and the same core network. Since radio spectrum is the most valuable resource in mobile technology, radio resource management (RRM) mechanisms are critical for the operation of a cellular network. One of the key RRM mechanisms is packet scheduling and it allocates suitable radio resources to each user for transmission of the downlink from the base station through the air interface to each mobile station. The overall objectives of this project are to study packet scheduling mechanism for LTE-Advanced and find an optimized packet scheduling algorithm(s) to fully utilize new features and challenges of LTE-Advanced. This project is an extension of previous work done in packet scheduling in LTE at Centre for Real-time Information Networks (CRIN), UTS. This thesis begins by explaining the design considerations used to create a computer simulation tool to model packet scheduling as well as other RRM mechanisms for LTE-Advanced. Thereafter, it will model, simulate, validate, and evaluate the performance of current well-known and new packet scheduling algorithms for LTE-Advanced. In this thesis, two new algorithms called optimized cross-CC proportional fair (OCPF) and optimized cross-CC M-LWDF (OCM) are proposed. (CC: component carrier) The OCPF algorithm can overcome the weaknesses of current algorithms and improve system throughput. The OCM can provide a more effective solution for realistic traffic with strict requirement on the quality of services (QoS)

A data-driven scheduler model for QoE assessment in a LTE radio network planning tool

The use of static system-level simulators is common practice for estimating the impact of re-planning actions in cellular networks. In this paper, a modification of a classical static Long Term Evolution (LTE) simulator is proposed to estimate the Quality of Experience (QoE) provided in each location on a per-service basis. The core of the simulator is the estimation of radio connection throughput on a location and service basis. For this purpose, a new analytical performance model for the packet scheduling process in a multi-service scenario is developed. Model parameters can easily be adjusted with information from radio connection traces available in the network management system. The simulation tool is validated with a large trace dataset taken from a live LTE network

RTXP : A Localized Real-Time Mac-Routing Protocol for Wireless Sensor Networks

Protocols developed during the last years for Wireless Sensor Networks (WSNs) are mainly focused on energy efficiency and autonomous mechanisms (e.g. self-organization, self-configuration, etc). Nevertheless, with new WSN applications, appear new QoS requirements such as time constraints. Real-time applications require the packets to be delivered before a known time bound which depends on the application requirements. We particularly focus on applications which consist in alarms sent to the sink node. We propose Real-Time X-layer Protocol (RTXP), a real-time communication protocol. To the best of our knowledge, RTXP is the first MAC and routing real-time communication protocol that is not centralized, but instead relies only on local information. The solution is cross-layer (X-layer) because it allows to control the delays due to MAC and Routing layers interactions. RTXP uses a suited hop-count-based Virtual Coordinate System which allows deterministic medium access and forwarder selection. In this paper we describe the protocol mechanisms. We give theoretical bound on the end-to-end delay and the capacity of the protocol. Intensive simulation results confirm the theoretical predictions and allow to compare with a real-time centralized solution. RTXP is also simulated under harsh radio channel, in this case the radio link introduces probabilistic behavior. Nevertheless, we show that RTXP it performs better than a non-deterministic solution. It thus advocates for the usefulness of designing real-time (deterministic) protocols even for highly unreliable networks such as WSNs

Advanced Radio Resource Management for Multi Antenna Packet Radio Systems

In this paper, we propose fairness-oriented packet scheduling (PS) schemes with power-efficient control mechanism for future packet radio systems. In general, the radio resource management functionality plays an important role in new OFDMA based networks. The control of the network resource division among the users is performed by packet scheduling functionality based on maximizing cell coverage and capacity satisfying, and certain quality of service requirements. Moreover, multiantenna transmit-receive schemes provide additional flexibility to packet scheduler functionality. In order to mitigate inter-cell and co-channel interference problems in OFDMA cellular networks soft frequency reuse with different power masks patterns is used. Stemming from the earlier enhanced proportional fair scheduler studies for single-input multiple-output (SIMO) and multiple-input multipleoutput (MIMO) systems, we extend the development of efficient packet scheduling algorithms by adding transmit power considerations in the overall priority metrics calculations and scheduling decisions. Furthermore, we evaluate the proposed scheduling schemes by simulating practical orthogonal frequency division multiple access (OFDMA) based packet radio system in terms of throughput, coverage and fairness distribution among users. As a concrete example, under reduced overall transmit power constraint and unequal power distribution for different sub-bands, we demonstrate that by using the proposed power-aware multi-user scheduling schemes, significant coverage and fairness improvements in the order of 70% and 20%, respectively, can be obtained, at the expense of average throughput loss of only 15%.Comment: 14 Pages, IJWM