Mobile Relay Station Handoff via Network Controller

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Solution Overview

Problem

Mobile relay stations (MRSs) face challenges in synchronization, handoff management, interference reduction, and reliability when moving between different base station coverage areas, particularly in environments like high-speed trains or ships, due to changing relationships with base stations and other MRSs, leading to complex handoffs and potential interference.

Innovation Solution

Implementing a specialized operation scheme for MRSs that includes MS-assisted discovery, random preamble transmission, and out-of-band relays to simplify synchronization and reduce interference, allowing MRSs to quickly handover and reconnect with minimal disruption, and using lead and secondary MRSs to manage connections and data forwarding within clusters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If MRSs use conventional handoff procedures when moving between base station coverage areas, then handoff functionality is provided, but handoff disruptions and interference increase due to changing relationships with multiple BSs and other MRSs

Engineering Contradiction:
Improvehandoff reliabilityVSAvoidhandoff management complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a network controller as an intermediary that centralizes handoff management for mobile relay stations. The network controller receives handoff requests from MRSs, determines optimal target BSs based on current locations and service requirements, and coordinates handoff execution. This mediator approach reduces the complexity burden on individual MRSs while improving handoff reliability through centralized coordination and interference management.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system implements feedback mechanisms where MRSs continuously report their locations, service requirements, and channel conditions to the network controller. The network controller uses this feedback to dynamically adjust handoff decisions and coordinate transmissions to minimize interference. This feedback loop enables adaptive handoff management that responds to changing environmental conditions while maintaining system-wide optimization.

Inventive Principle:
Principle #23Feedback

2Reliability

If MRSs maintain connections with multiple base stations simultaneously, then service continuity is improved, but interference and coordination complexity increase

Engineering Contradiction:
Improveservice continuityVSAvoidinterference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements dynamic connection management where the set of active base stations for each MRS is not fixed but adapts based on current location, service requirements, and channel conditions. The network controller dynamically determines which MRSs should maintain connections with which BSs, allowing the system to optimize for both service continuity and interference minimization in real-time. This dynamic approach enables flexible multi-connection strategies that respond to changing environmental conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system applies different connection strategies to different MRSs based on their specific local conditions. Each MRS evaluates its own service requirements, mobility characteristics, and channel environment to determine the optimal number and identity of connected BSs. The network controller coordinates these local decisions to ensure global interference management. This local quality approach allows tailored connection management that optimizes service continuity for each MRS while considering overall system interference.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If MRSs perform frequent synchronization and handoffs, then connection quality is maintained, but handoff disruptions and system complexity increase

Engineering Contradiction:
Improvesynchronization accuracyVSAvoidhandoff disruption time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements preliminary handoff preparation where the network controller identifies potential target base stations in advance and pre-establish synchronization parameters and resource allocations. When an MRS approaches a handoff point, the handoff can be executed more quickly because the target BS and transmission parameters are already prepared. This preliminary action reduces the actual handoff disruption time while maintaining synchronization accuracy through pre-coordinated parameters.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2122857B1Moving relay technology option
Publication Date: 2015.09.23 BLACKBERRY LTD
  • EP2122857B1 patent drawingFigure 1
  • EP2122857B1 patent drawingFigure 2
  • EP2122857B1 patent drawingFigure 3

AI summary

A mobile relay system for supporting communications between a fixed station and mobile terminals comprising a plurality of mobile relay stations that are associated with each other and provided on a moving platform, wherein each of the plurality of mobile relay stations is capable of facilitating communications with mobile terminals within communication range and at least one of the plurality of mobile relay stations is further capable of facilitating communications with a fixed station within communication range of the at least one of the plurality of mobile relay stations.