Long Term-Evolution (Lte) Wireless System

Canadian Journal on Multimedia and Wireless Networks, Vol. 2, No. 4, December 2011

A Novel Cross-Layer Scheduling Algorithm for Long Term-Evolution (LTE) Wireless System

Mohsen M. Tantawy , Adly S. Tag Eldien , and Rokaia Mounir Zaki 1

Abstract

— The Third Generation Partnership Project

(3GPP) is specifying the Long Term Evolution (LTE) of thirdgeneration cellular systems to meet demands for higher user bit rates. In this paper, we propose a novel Quality of Service (QoS)-guaranteed cross-layer scheduling algorithm for LTE system that allocates resources as resource blocks and also provide the modulation and coding scheme, among users with different traffic loads. Numerical results demonstrate that the proposed algorithm can provide better behavior for QoSbased services than other previous resource allocation algorithms.

Key words — Cross-Layer scheduling algorithms, 3GPP LTE, OFDMA, QoS, GBR, Non-GBR.

Rokaia Mounir Zaki is with faculty of engineering, Benha University, Electrical Engineering Department, Cairo, Egypt (e-mail: rukaia.emam@feng.bu.edu.eg).

In LTE, The configured classes have been specified in two categories of bearers, Guaranteed Bit Rate (GBR) and NonGuaranteed Bit-Rate (Non-GBR) bearers [6]. QoS Class Identifier (QCI) is an index that identifies a set of locally configured values for three QoS attributes: priority, delay and loss rate. QCI is signaled instead of the values of these parameters. The standard QCI classes are shown in Table I[7], [8]. When a connection (or bearer) is established between the UE and the LTE core network a QCI is specified. This defines whether the bearer is guaranteed bit-rate or not [5], [9].

TABLE I STANDARDIZED QoS CLASS IDENTIFIERS (QCIs) FOR LTE [19]. Resource Delay QCI Priority Services type budget 1 GBR 2 100 ms VoIP. 2 GBR 4 150 ms Video call. 3 GBR 5 300 ms Streaming. 4 GBR 3 50 ms Real time gaming. 5 Non-GBR 1 100 ms IMS signaling. 6 Non-GBR 7 100 ms Interactive gaming. 7 Non-GBR 6 300 ms...