Handover Decision in Soft Cell Networks

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Solution Overview

Problem

Existing handover decision mechanisms in LTE networks fail to optimally manage the discrepancy between link quality on the control plane and the data plane in heterogeneous networks with the soft cell concept, leading to suboptimal handover decisions.

Innovation Solution

A method and device that consider both control plane and data plane link quality values to determine handover decisions, allowing for a more comprehensive evaluation of link quality between a user equipment and both the serving cell and target cell, using a comparison process to initiate handoffs based on weighted sums of control plane and data plane values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If handover decisions are based only on control plane link quality values, then the handover decision process is simple, but the handover decisions are suboptimal in heterogeneous networks with soft cell concept where control plane and data plane link qualities may differ significantly

Engineering Contradiction:

Improvehandover decision accuracyVSAvoidhandover decision process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines control plane link quality values and data plane link quality values into a unified handover decision metric. The network node receives both types of values from the UE and performs a joint comparison to determine whether to initiate handover, merging previously separate evaluation processes into a single comprehensive decision mechanism.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces a new parameter dimension (data plane link quality) to the existing handover decision framework. By adding this additional parameter and comparing it alongside control plane values, the system transforms the single-parameter decision process into a multi-parameter evaluation, improving decision accuracy at the cost of increased complexity.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If the network monitors both control plane and data plane link quality, then comprehensive link quality assessment is achieved, but the measurement and processing overhead increases

Engineering Contradiction:

Improvelink quality assessment accuracyVSAvoidhandover decision time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The UE performs measurements of both control plane and data plane link quality values in advance and reports them to the network node. This preliminary action allows the network node to have both measurement values ready when making the handover decision, reducing the time required at the decision moment while maintaining comprehensive assessment accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The UE autonomously measures and reports both control plane and data plane link quality values to the network node without requiring additional network-initiated measurement procedures. This self-service approach enables comprehensive measurement while minimizing network overhead and decision time.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS8837290B2Handover in a soft cell network

Publication Date: 2014.09.16 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

Devices and methods for making a determination whether or not to handover a user equipment (UE) from a serving cell to a target cell are disclosed. The decision is based on a comparison that includes both control plane and data plane link quality considerations. The disclosed devices and methods may be applied to handover determinations in heterogeneous networks that implement a soft cell configuration.