RNO Case Security Level:

Case Title: Improve HSDPA throughput by decreasing HSDPA service cell change delay time AuthorA00319733

Date3 - 6 - 2015

Product & VersionRAN-17

Problem DescriptionIn Country L Project W the customer wanted to improve HSDPA throughput to improve end-user perception.

Alarm InformationNone

Handling ProcessTo improve overall HSDPA throughput and improve user experience HSDPA Fast Service Cell Change feature was proposed to customer.

During an HSDPA serving cell change, the RNC sets the activation time for the HSDPA serving cell change to 1s and includes this activation time in the Uu interface configuration message sent to the UE. The UE is handed over to the target cell at this activation time. However, the signal quality of the source serving cell may deteriorate during the activation time, which reduces the HSDPA throughput.

When the FAST_HSDPA_SERV_CELL_CHANGE_SWITCH is set ON the RNC includes the IE Delay restriction flag in the HSDPA serving cell change message. After receiving this message, the UE immediately returns to the RNC an HSDPA serving cell change complete message.

The intention was to avoid reception gaps (up to 2.56 seconds long) in case a reconfiguration message has been received by the UE after its activation time. With the introduction of this delay restriction flag, the network can order the UE to chose an activation time T as soon as possible, therefore the UE will avoid to wait until the next occurrence of the CFN(Connection Frame Number is an indicator as to which radio frame the first data was received on uplink or shall be transmitted on downlink. It can have a value of 0-255 and is 8 bits long)

The fast HSDPA serving cell change function has been introduced. This function significantly shortens the HSDPA serving cell change delay and improves the HSDPA throughput. The delay is the duration between the time the RNC sends a PH CH RECFG message and the time the RNC receives a PH CH RECFG CMP message from the UE.

H_SERV_CELL_CHANGE_MSG_OPT_SWITCH

When the H_SERV_CELL_CHANGE_MSG_OPT_SWITCH is set to ON, the size of the HSDPA serving cell change message is reduced. This shortens the delay of the HSDPA serving cell change message and improves the success rate of HSDPA serving cell change.

MML Command:

SET URRCTRLSWITCH: OptimizationSwitch3= FAST_HSDPA_SERV_CELL_CHANGE_SWITCH-1;SET URRCTRLSWITCH: OptimizationSwitch3= H_SERV_CELL_CHANGE_MSG_OPT_SWITCH-1;

Root CauseDue to delay during HSDPA service cell change the signal quality of the source serving cell may deteriorate during that time, which reduces the HSDPA throughput.

SolutionReduce the delay during service cell change to improve user experience

ResultHSDPA throughput improved

Suggestion and Summary

AttachmentNULL

Reference

2015-06-16HUAWEI ConfidentialPage1, Total3