23,718 research outputs found
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
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