Base Station Multicast-Unicast Switching Threshold

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Solution Overview

Problem

Seamless mobility of mobile terminals across LTE networks with different MBSFN areas and transitions between multicast and unicast modes is not supported, leading to service interruptions due to resource load imbalances.

Innovation Solution

A method and base station configuration that dynamically adjust thresholds for switching mobile terminals from multicast/broadcast to unicast based on network loading and signal quality, allowing for controlled resource allocation and minimizing service disruptions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mobile terminals switch to unicast before transition to another cell/sector, then service interruption is reduced, but network resource load increases

Engineering Contradiction:
Improveservice continuityVSAvoidnetwork resource load
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent dynamically adjusts the threshold parameter for switching from multicast to unicast based on network load conditions. When network load is high, the threshold is raised to delay switching; when load is low, the threshold is lowered to allow earlier switching. This parameter adaptation resolves the contradiction by balancing service continuity requirements against network resource conservation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The switching mechanism transitions from a static threshold-based approach to a dynamic load-aware approach. The base station continuously monitors network load and adjusts switching decisions in real-time, allowing the system to adaptively balance between maintaining service continuity and controlling resource consumption under varying network conditions.

Inventive Principle:
Principle #15Dynamics

2Quantity of substance

If mobile terminals remain on multicast/broadcast, then network resource efficiency is improved, but service interruption occurs during mobility

Engineering Contradiction:
Improvenetwork resource efficiencyVSAvoidservice continuity
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the base station receives load information from the network and adjusts multicast-to-unicast switching decisions accordingly. This feedback loop enables the system to maintain high resource efficiency by keeping terminals on multicast when possible, while only switching to unicast when necessary for service continuity or when load conditions permit.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary switching to unicast before the mobile terminal actually transitions to another cell or MBSFN area. This advance switching ensures that when the terminal does move, it is already in unicast mode and can maintain service continuity without interruption, while the decision is made based on current network load conditions.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If seamless mobility is implemented across different MBSFN areas, then service continuity is improved, but network complexity increases

Engineering Contradiction:
Improveservice continuityVSAvoidnetwork complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces the base station as an intermediary that manages the complexity of seamless mobility. Rather than requiring complex coordination between multiple MBSFN areas and terminals, the base station centralizes the decision-making process for multicast-to-unicast switching, simplifying the overall network architecture while enabling seamless mobility through controlled switching.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3437397B1Mobile communications network
Publication Date: 2022.10.19 BRITISH TELECOM PLC
  • EP3437397B1 patent drawingFigure 1~2
  • EP3437397B1 patent drawingFigure 3a~3b
  • EP3437397B1 patent drawingFigure 4a~4c

AI summary

A method of operating a mobile communications network comprising a plurality of base stations and a base station for a mobile communications network, in which the base station comprises a plurality of transmitters, a plurality of receivers and a processor. Each transmitter is configured to transmit radio signals to a plurality of mobile terminals. Each receiver is configured to receive radio signals from a plurality of mobile terminals. The processor is configured to serve a mobile terminal via the transmitter over multicast/broadcast across a radio link; receive information from the mobile terminal being served by the transmitter, in which the information derives from signal quality of a multicast/broadcast serving signal received at the mobile terminal from the transmitter; and provide to the mobile terminal first instructions based on a first comparison of the quality of the multicast/broadcast serving signal received at the mobile terminal. The comparison is based on a first threshold; in which the first instructions instruct the mobile terminal to switch to unicast; and in which the processor is further configured to vary the first threshold in dependence on a measure of loading of the network.