HSDPA Soft Handover via DPDCH Channel Reconfiguration

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Solution Overview

Problem

In 3G mobile communication systems employing HSDPA, hard handovers during cell changes result in data loss, re-transmission, and significant delays, particularly affecting real-time services like VoIP and video telephony due to the inability to concurrently receive data from multiple base stations, leading to poor communication quality.

Innovation Solution

Implementing a method that initiates a handover procedure by switching from High Speed Physical Downlink Shared Channel (HS-PDSCH) to Dedicated Physical Data Channel (DPDCH) via a Radio Network Controller (RNC), enabling soft handover and concurrent data reception from multiple base stations, thus avoiding data transmission interruptions and delays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hard handover procedure is used for cell change in HSDPA system, then the handover can be completed with existing infrastructure, but data transmission is interrupted causing delays of 300ms and data loss

Engineering Contradiction:

Improvedata transmission continuityVSAvoidhandover delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent performs physical channel reconfiguration from HS-PDSCH to DPDCH before executing the handover procedure. This preliminary action prepares the mobile device to receive data on DPDCH during handover, ensuring continuous data reception without interruption or delay

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent maintains continuous data transmission during handover by switching to DPDCH which allows the mobile device to concurrently receive data from multiple base stations. This eliminates the interruption inherent in hard handover while maintaining system compatibility

Inventive Principle:

Principle #20Continuity of useful action

2Reliability

If hard handover is performed, then the implementation is simple with existing HSDPA infrastructure, but the mobile device cannot concurrently receive data from multiple base stations leading to data loss

Engineering Contradiction:

Improvedata reception reliabilityVSAvoidchannel reconfiguration complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces DPDCH as an intermediary channel between HS-PDSCH and the handover process. By reconfiguring the physical channel to DPDCH before handover, the system enables concurrent data reception from multiple base stations while maintaining compatibility with existing HSDPA infrastructure

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the physical channel parameter from HS-PDSCH to DPDCH during handover preparation. This parameter change enables the mobile device to operate in a mode that supports soft handover characteristics, allowing concurrent data reception without requiring fundamental hardware changes

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8761120B2Method of handling cell change in wireless communication systems and communication device thereof

Publication Date: 2014.06.24 WISTRON CORP

AI summary

A method of handling cell change for a mobile device employing a high speed downlink package access (HSDPA) technology in wireless communication systems. The method includes initiating a handover procedure to change a serving cell of the mobile device when the mobile device moves from a HSDPA cell into another HSDPA cell, performing a physical channel reconfiguration procedure from a high speed physical downlink shared channel (HS-PDSCH) to a dedicated physical data channel (DPDCH), wherein the physical channel reconfiguration procedure is initiated via a Radio Network Controller (RNC), and performing the handover procedure.