Vol 6, No 2 (2015) > Electrical, Electronics and Computer Engineering >

Modification of Round Robin and Best CQI Scheduling Method for 3GPP LTE Downlink

Muhamad Asvial, Galih Dewandaru, Arief Noor Rachman



In the case of downlink LTE, scheduler is an important element which
assigns RB allocation for different users in a cell. RB is the smallest element
which can be assigned by scheduler. This work proposes a new scheduler
algorithm by considering the tradeoff balance between throughput and fairness
among users. The proposed scheduler combines the benefit from the Best CQI and Round Robin Scheduler. The first time slot applies a Round Robin algorithm in the basis of a continuity
in user sequence at the entire sub frames. The second time slot applies the Best CQI algorithm with a fairness
enhancement. At 15dB SNR, the throughput of each scheduler is 61.2Mbps for Best CQI scheduler, 32.3Mbps for Round Robin scheduler, and 48Mbps for
the proposed scheduler. Based on Jain’s Fairness Index, the proposed scheduler
has a fairness index of 0.97. For 20 users at 5MHz bandwidth, the average
queuing delay gives the value of 5ms for Round
scheduler, 29.38ms for Best CQI
scheduler, and 0.94ms for the proposed scheduler.

Keywords: LTE, Scheduling, Best CQI, Round Robin, fairness, throughput

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. 3GPP organization. http://www.3gpp.org/About-3GPP.

. Zyren, Jim. (July 2007). Overview of the 3GPP Long Term Evolution Physical Layer.

White Paper freescale semiconductor.

. Silberschatz, Abraham; Galvin, Peter B.; Gagne, Greg (2010). "Process

Scheduling". Operating System Concepts(8th ed.). John Wiley and Sons(Asia).

. Ku, Gwanmo. (April 2012). Scheduling in LTE. Adaptive Signal Processing and

Information Theory Research Group.

. Dikamba, Tshiteya. (March 2011). Downlink Scheduling in 3GPP LTE.


. Gavrilovska, Liljana. (November 2011). Novel Scheduling Algorithms for LTE

Downlink Transmission. Paper published in Telecommunications Forum (TELFOR),


. LTE downlink physical layer. http://www.electronicdesign.com. Accessed on 20 Mei

.OFDM basics.http://www.ee.ui.ac.id/wasp/wp-content/uploads/2011/01/ OFDM- Basics.pdf. Accessed on 8 April 2013.

. Orthogonal frequency division multiplexing.

http://digilib.ittelkom.ac.id/index.php?option=com_content&view=article&id=1079:orthogonal-frequency-division-multiplexing-ofdm&catid=17:sistem-komunikasi-bergerak&Item id=14. Accessed on 8April 2013

. Xiaowen Li, Qianjun Fang, Liuwei Shi. A Effective SINR Link to Sistem Mapping

Method for CQI Feedback in TD-LTE System. 2011. IEEE

. E.Dahlman, S.Parkvall, J.Skold, P.Beming. (2008). ''3G Evolution HSPA and LTE

for Mobile Broadband'', Elsevier.

. Borko Furht, Syed A.Ahson. (2009). Long Term Evolution 3GPP LTE Radio and

Cellular Technology.