International Journal of Engineering Research ISSN:2319-6890)(online),2347-5013(print) Volume No.4, Issue No.6, pp : 277-281 01 June 2015 IJER@2015 Page 277 Downlink Scheduling in Long Term Evolution Md. Anwar Hossain, AFM Zainul Abadin Department of Information and Communication Engineering Pabna University of Science & Technology manwar_ice@yahoo.com, abadin.7@gmail.com Abstract: This is an investigated research article on resource block scheduling of Long Term Evolution (LTE). LTE is one of the evolutions of the Universal Mobile Telecommunication System (UMTS). It provides internet access to mobile users through smart phone, laptop and other android devices. LTE offers a high speed data and multimedia services. It supports data rates up to 100 Mbps in the downlink and 50 Mbps in the uplink transmission. Our research investigation was aim to the downlink scheduling. We have considered The Best CQI scheduling algorithm and the Round Robin scheduling algorithm. The implementation, analysis and comparison of these scheduling algorithms have been performed through MATLAB simulator. We have analyzed the impact of the scheduling schemes on the throughput and the fairness of both scheduling schemes. Here we have proposed a new scheduling algorithm that achieves a compromise between the throughput and the fairness. Orthogonal Frequency Division Multiplexing (OFDM) has been adopted as the downlink transmission scheme. We have considered the impact of the channel delay on the throughput. In addition, MIMO transceiver systems have been implemented to increase the throughput. Keywords- Long Term Evolution (LTE), Universal Mobile Telecommunication System (UMTS), Best CQI, Round Robin, Orthogonal Frequency Division Multiplexing (OFDM), SISO , MIMO. I. Introduction We are now living in the mobile broadband era. We are concentrated enough to multimedia applications through internet. Live streaming, online gaming, IPTV, mobile TV, etc. become very popular applications today. These applications require higher data rate. The Third-generation Partnership Project (3GPP) started to work on solutions to these challenges and came up with the HSPA. The HSPA is currently used in 3G phones for such applications. LTE is the evolution of the Third-generation of Universal Mobile Telecommunications System (UMTS). LTE intends to create a new radio-access technology which will provide high data rates, a low latency and a greater spectral efficiency. It provides internet access to mobile users through smart phone, laptop and other android devices. In the coming years LTE mobile broadband technology will be widely used by devices such as notebooks, smart phones, gaming devices and video cameras. The Long Term Evolution provides a high data rate and can operate in different bandwidths ranging from 1.4MHz up to 20MHz. LTE offers a high speed data and multimedia services. It supports data rates up to 100 Mbps in the downlink and 50 Mbps in the uplink transmission. It improves system capacity and coverage also reduces operating costs. Furthermore LTE supports Multiple Input Multiple Output (MIMO) transceiver system. Recently (MIMO) systems have drawn a lot of attention in wireless communication. It accelerates the system to achieve high peak data rates. Moreover LTE operates both in Frequency Division Duplexing (FDD) as well as in Time Division Duplexing (TDD) and can be deployed in different bandwidths. With TDD the uplink and downlink operate in same frequency band whereas with FDD the uplink and downlink operate in different frequency bands. A scheduler allocates the shared resources (time and frequency) among user terminals. The scheduler is a key element in the Base Station (BS) since it determines to which users the resource blocks should be assigned. Best CQI scheduling and Round Robin scheduling have been selected by their characteristics. The Best CQI scheduling optimizes the user throughput by assigning the resource block to the user with the good channel quality and the Round Robin scheduling is fair in the long term since it equally schedules the Mobile station (MS). In general cell-centre users have a good channel quality compare to the cell-edge users. In order to find a trade-off between the throughput and the fairness a new scheduling algorithm has been proposed. The proposed new scheduling algorithm can be considered as a compromise between the Best CQI scheduling and the Round Robin scheduling. II. Material and Methodology The downlink transmissions in LTE technology are grouped in frame. Figure-1 shows the LTE frame structure. Figure-1: LTE Frame structure