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Prioritised forwarding of HSDPA packets to the new Node B following handover of the HS-DSCH

IP.com Disclosure Number: IPCOM000031471D
Original Publication Date: 2004-Sep-27
Included in the Prior Art Database: 2004-Sep-27
Document File: 2 page(s) / 23K

Publishing Venue

Motorola

Related People

Steve Barrett: AUTHOR

Abstract

This paper describes a method of maximising system efficiency and end-user QoS experience when there is a change in the cell from which the UMTS High Speed Downlink Shared CHannel (HS-DSCH) is transmitted.

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Prioritised forwarding of HSDPA packets to the new Node B following handover of the HS-DSCH

by Steve Barrett

Abstract

This paper describes a method of maximising system efficiency and end-user QoS experience when there is a change in the cell from which the UMTS High Speed Downlink Shared CHannel (HS-DSCH) is transmitted.

Introduction

The paper discusses an algorithm which can be implemented in the Radio Network Controller (RNC) of a Release 5 UMTS HSDPA system, though the ideas behind the algorithm might also be applied in other telecommunication systems.  

In particular a method is discussed by which system efficiency and end-user QoS is improved by minimising the delay with which packets of a bearer carried on HS-DSCH are forwarded to the new Node B following a change in the cell from which the HS-DSCH is scheduled.  

Problem(s) To Be Solved

When the HS-DSCH associated with a given user is "handed-over" from one Node B to another, it is necessary for the RNC to forward packets over the Iub to the HSDPA scheduler in the new Node B.  This should ideally be done in such a way that overall system efficiency is maximised and the QoS requirements of individual connections are satisfied whilst taking into account the fact that backhaul resource is both limited and expensive.  A solution in which the packets of a handed over bearer are treated in exactly the same way as those of all other bearers from the point of view of scheduling onto the backhaul is not expected to perform optimally.   Hence, in the next section a method is proposed which will perform better than such a scheme.

Proposed Solution to the Problem(s)

The proposal is that either during the handover of HS-DSCH (High Speed Downlink Shared CHannel) or immediately following the handover, MAC_d HSDPA PDU's (ie. MAC layer HSDPA packets) for the handed-over connection should be forwarded by the RNC to the new Node B with priority over the sending of packets on the other MAC_d flows, ie. with priority over those ot...