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Vol. 1 Issue IV, November 2013 ISSN: 2321-9653
INTERNATIONAL JOURNAL FOR RESEARCH IN AP PLIED SCIENCE AN D E N G I N E E R I N G T E C H N O L O G Y (I J R A S E T)
Scheduling Algorithms Implementation for LTE Downlink S. Sravani, M.Tech Student Dept. of ECE, St. Ann’s College of Engineering & Technology, Chirala, INDIA. Sravani.ayachitula@gmail.com
K. Jagadeesh Babu, Professor Dept. of ECE, St. Ann’s College of Engineering & Technology, Chirala, INDIA. Jagan_ec@yahoo.com
Abstract: The increasing demand for cellular communications leads to the development of Long Term Evolution (LTE). LTE is the evolution for existing 3G mobile networks which offers higher capacity, efficient utilization of radio resources, lower latency. As a core functionality of LTE downlink radio resource management, packet scheduling algorithms plays a vital role. Maximum SNR( Max SNR), Round Robin, Proportional Fair are the conventional scheduling algorithms. The main contribution of Max SNR is towards maximizing system throughput. Round Robin and Proportional algorithms tries to please the fairness among the users. In this paper two new scheduling Algorithms has been proposed in order to give higher capacity than Round Robin and higher fairness than Max SNR. Keywords: LTE, OFDMA, Packet Scheduling, Max SNR, Round Robin, Proportional Fair.
I.
INTRODUCTION
LTE release 8 is the standard for Radio Access Network specified by 3GPP [1]. 3GPP, the 3rd Generation Partnership Project is collaboration between groups of telecommunications associations known as organizational partners. LTE is a standard [2] for Radio Access Network (RAN) part of Evolved – Universal Terrestrial Radio Access (E-UTRA). The standard is targeted to support 100Mbps for downlink and 50Mbps for uplink. It uses Orthogonal Frequency Division Multiple Access (OFDMA) for downlink and Single Carrier – Frequency Division Multiple Access (SC – FDMA) for uplink. WCDMA is used for 3GPP Release 6. It is verified that OFDMA is outperforming than WCDMA in both broadcast and unicast services [3]. The efficient use of radio resources has become the challenging task for next generation wireless communication systems. The scarcity of radio resources, diverse Quality of Service (QoS) requirements [4] and wireless channel conditions
complicate the scheduling and radio resource management. The main function of the scheduler is to intelligently allocate radio resources to users in order to achieve high system performance in terms of efficiency and fairness. This makes the scheduling algorithm a key component in optimizing the system performance across the physical (PHY) and Media Access Control (MAC) layers [5]. The Two key performance indicators considered are fairness and efficiency. Efficiency is evaluated in terms of system throughput, which is sometimes unfair to users with bad channel conditions. On the other hand, absolute fairness may lead to low bandwidth efficiency. Therefore, a tradeoff between efficiency and fairness is desired.
II.
B RIEF INTRODUCTION TO CONVENTIONAL SCHEDULING ALGORITHMS
Max SNR, Round Robin and Proportional Fair are the three conventional scheduling algorithms for High Speed Packet Access (HSPA). For every eNB all the active users are
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