Performance analysis and enhancements of packet forwarding in LTE

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Volume Title

Perustieteiden korkeakoulu | Master's thesis

Date

2009

Major/Subject

Tietokoneverkot

Mcode

T-110

Degree programme

Language

en

Pages

(11+) 55 s.

Series

Abstract

At handover between base stations in Long Term Evolution (LTE), data is forwarded from a source eNB to a target eNB. The mechanism for handling the packet forwarding is specified in Third Generation Partnership Project (3GPP) Release 8 specifications. The goal of the thesis is to analyse, evaluate and improve the packet forwarding mechanism. The techniques to reduce the amount of forwarded data in the downlink will be studied as a part of the thesis. Such enhancements include modifications to the Radio Link Control (RLC) protocol, as well as improved interactions with other layers, most notably Packet Data Convergence Protocol (PDCP) and Radio Resource Control (RRC). Performance criteria considered for evaluating these techniques include the PDCP buffer size at the source eNB, uplink RLC status load and user object bit rate. The thesis recommends the LTE network to poll the UE more frequently during the ongoing handover scenarios, compared to the case when handover is not ongoing. This allows the source eNB to be as up to date to the UE reception state as possible, and thus reduces the number of unacknowledged PDCP SDUs to he forwarded to the target eNB. Based on the simulation results, this proposed technique proves to be the most efficient in terms of lower PDCP buffer size at the source eNB, lower uplink RLC status load and higher user object bit rate.

Description

Supervisor

Tarkoma, Sasu
Zander, Jens

Thesis advisor

Larmo, Anna

Keywords

data forwarding, handover, LTE, PDCP, RLC

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