Soft Handover Uplink Scheduling Using Combined Grant Indicators

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Solution Overview

Problem

In UMTS WCDMA communication systems, user equipment (UE) in soft handover regions face challenges with efficient scheduling of enhanced dedicated channels due to overhead in code and power transmission resources, and difficulty in determining whether to transmit based on varying scheduling assignment information from multiple Node Bs.

Innovation Solution

A method and apparatus for UE in soft handover regions to determine a data rate using combined scheduling grant indicators from both serving and non-serving Node Bs, reducing downlink signaling overhead by employing dedicated and common scheduling assignment methods, and managing uplink resources efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If dedicated scheduling assignment is used from serving Node B, then scheduling accuracy is improved, but downlink signaling overhead increases

Engineering Contradiction:

Improvescheduling accuracyVSAvoiddownlink signaling overhead

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent segments the scheduling assignment information into two parts: common scheduling assignment (transmitted by non-serving Node Bs) and dedicated scheduling assignment (transmitted by serving Node B). This segmentation allows the system to maintain scheduling accuracy through dedicated information while reducing overall overhead by using common information for basic scheduling parameters.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The common scheduling assignment serves multiple functions by being transmitted by non-serving Node Bs and providing basic scheduling information that applies to multiple UEs. This multi-functionality reduces the need for redundant dedicated scheduling assignments from each Node B, thereby reducing overall downlink signaling overhead while maintaining scheduling accuracy through the serving Node B's dedicated assignment.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Quantity of substance

If common scheduling assignment is used from non-serving Node Bs, then downlink signaling overhead is reduced, but scheduling precision deteriorates

Engineering Contradiction:

Improvedownlink signaling overheadVSAvoidscheduling precision

Core Design Contradiction:

Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent segments scheduling information into common and dedicated parts, where common scheduling assignment from non-serving Node Bs provides basic scheduling parameters with reduced overhead, while dedicated scheduling assignment from serving Node B provides precise scheduling information. This segmentation resolves the contradiction by assigning different precision requirements to different parts of the scheduling information.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The serving Node B acts as an intermediary that receives common scheduling assignment information and supplements it with dedicated scheduling assignment information. This intermediary role ensures that even though non-serving Node Bs transmit only common information (reducing overhead), the final scheduling decision maintains high precision through the serving Node B's dedicated information.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If UE receives scheduling information from multiple Node Bs, then coverage is improved, but difficulty in determining transmission increases

Engineering Contradiction:

ImprovecoverageVSAvoiddifficulty in determining transmission

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the role of Node Bs into serving and non-serving categories, with clear functional differentiation. Non-serving Node Bs transmit only common scheduling assignment information, while the serving Node B transmits dedicated scheduling assignment information. This segmentation provides a clear decision-making framework for the UE, reducing the complexity of determining transmission despite receiving information from multiple Node Bs.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of having each Node B independently make scheduling decisions (which would increase UE complexity), the patent inverts the approach by having non-serving Node Bs provide only common information and reserving the final scheduling decision authority with the serving Node B. This inversion simplifies the UE's decision-making process while maintaining the benefits of multi-Node B coverage.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS7561550B2Method and apparatus for scheduling user equipment in a soft handover region for uplink packet transmission

Publication Date: 2009.07.14 SAMSUNG ELECTRONICS CO LTD

AI summary

A scheduling method and apparatus are provided for soft handover in a user equipment (UE) in in a mobile communication system supporting an enhanced uplink packet data service. A receiver receives dedicated scheduling assignment information for dedicated scheduling assignment from a serving Node B, and receives at least one scheduling grant indicator for common scheduling assignment from at least one non-serving Node B. A first scheduling decider determines a combined scheduling grant indicator by combining at least one scheduling grant indicator received from the at least one non-serving Node B. A second scheduling decider determines whether to use the combined scheduling grant indicator according to a predetermined reference, and a maximum rate of an uplink according to the dedicated scheduling assignment information or the combined scheduling grant indicator. A transport format decider determines a transport format of an uplink within the maximum rate.