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3G HSDPA Performance In Mobile Internet Connections
KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. (CCSlab)
2004 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

A key objective for 3G wireless networks, such as the Universal Mobile Telecommunication System (UMTS), is the explicit support for data communications for mobile users. Today, the dominant transport protocol in the Internet is the Transport Control Protocol (TCP). Since TCP was not tailored for wireless networks, there are some performance issues occurring when TCP traffic is transferred over a UMTS radio link.

In this paper, the characteristics of TCP and UMTS are specified and the problems of TCP over UMTS dedicated channels (DCHs) are analyzed. The problem is high delays implying low utilization of allocated resources for small file transfers or due to packet losses. High Speed Downlink Packet Access (HSDPA)’s potential to solve the problem is studied. Since in HSDPA, High-Speed Downlink shared channel (HS-DSCH) is introduced as an alternative of DCH on downlink packet access, a model of HS-DSCH is built and simulations are performed in order to compare its TCP performance with DCH. The focus is on studying retransmission delay and Block Error Rate (BLER) targets. Some scheduling methods are also compared. The results indicate that HS-DSCH gives better TCP performance than a DCH, and that advanced scheduling methods gives similar result as round robin if there are packet losses. Moreover, a somewhat surprising result is found regarding fast retransmission and channel utilization for increasing BLER targets.

Abstract [sv]

I denna rapport specificeras karaktäristiken för TCP and UMTS, och problemet med TCP över dedikerade UMTS kanaler analyseras. Problemet är höga fördröjningar som medför låg utnyttjande grad av allokerade resurser vid överföring av små filer eller vid paket förluster. High Speed Downlink Packet Access (HSDPA)’s potential att lösa problemet studeras. En modell av HS-DSCH konstrueras och simuleringar utförs för att jämföra dess TCP prestanda med DCH. Fokus är på att studera återsändningsfördröjning och BLER riktvärden. Några scheduleringsmetoder jämförs också. Resultatet indikerar att HS-DSCH ger bättre TCP prestanda än DCH, och att avancerad scheduleringsmetoder ger liknande resultat som round robin vid paket förluster. Dessutom har ett ganska överraskande resultat funnits kring snabb återsändning och kanal utnyttjande grad då BLER riktvärdet ökar.

Place, publisher, year, edition, pages
2004. , 46 p.
Trita-IMIT-LCN. AVH, ISSN 1651-4106 ; IMIT/LCN 2004-02
Keyword [en]
3G, UMTS, TCP performance, HSDPA, HS-DSCH
Keyword [sv]
3G, UMTS, TCP prestanda, HSDPA, HS-DSCH
National Category
Communication Systems
URN: urn:nbn:se:kth:diva-93068OAI: diva2:514744
Subject / course
Telecommunication Systems
Educational program
Master of Science - Internetworking
2004-03-22, Seminar room Grimeton, Isafjordsgatan 30B, Kista, 10:00 (English)
Available from: 2012-04-13 Created: 2012-04-10 Last updated: 2013-09-09Bibliographically approved

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