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Optimization of Handover Algorithm in 3GPP LTE
KTH, School of Electrical Engineering (EES), Communication Theory.
2009 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

One of the key characteristics of Long Term Evolution (LTE) is to support seamless and reliable handover to meet a strict delay requirement. Handover triggering is an important component in handover design since the success and the efficiency of the handover, to a large extent, depends on the accuracy and timeliness of the decision. The LTE standard supports hysteresis margin and Time-to-Trigger (TTT) to trigger the handover and select the target cell.

In this thesis, the impacts of triggering setting {hysteresis/TTT} on handover performance have been investigated for different scenarios with low, medium and high system loads. System level simulations have been done and it has been shown that the setting can affect the handover loss rate, system and service performance. The optimal setting for each case has been proposed; it depends on both User Equipment (UE) speed and cell size. For UE moving at high speed, the TTT should be short so as to avoid the handover delay and the value of hysteresis should be relatively large to mitigate channel variations and ping-pong effects. On the other hand, for a low speed UE, long TTT should be used to combat channel variations and ping-pong effects while small hysteresis is needed for decreasing handover delay. When the cell size becomes larger, smaller hysteresis and long TTT tend to have better performance. Results have shown that the system load does not affect significantly the optimal setting of handover hysteresis and TTT. It has also been shown that the optimal triggering setting can improve the performance in the absence of coverage and capacity limitations. However, when there are coverage or capacity limitations, the effects of the triggering settings become small and other optimization methods are applied to improve the handover performance. Using fast triggering and adapting the size of measurement report can decrease the handover loss rate in these scenarios and hence improve the handover performance.

Place, publisher, year, edition, pages
2009. , 79 p.
Series
, XR-EE-KT, 2009:002
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
URN: urn:nbn:se:kth:diva-189887OAI: oai:DiVA.org:kth-189887DiVA: diva2:949733
External cooperation
Ericsson
Subject / course
Communication Theory
Presentation
2009-03-04, Stockholm, 12:00 (English)
Supervisors
Examiners
Note

QC 201060722

Contact pi@ece.kth.se for fulltext of the thesis.

Available from: 2016-07-22 Created: 2016-07-22 Last updated: 2016-09-30Bibliographically approved

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