Relay Station Handover Timing Adjustment

Solution Overview

Problem

In mobile communication systems, handover processes between base stations and relay stations can lead to synchronization loss between mobile stations and relay stations, causing communication disruptions and resource overhead during recovery, especially when multiple mobile stations are involved.

Innovation Solution

An intermediate station method that includes receiving a handover trigger, determining if timing changes for preamble and broadcast messages are needed, estimating the handover timing, instructing downstream stations to resynchronize, and performing the handover to a target station to maintain synchronization and prevent interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the relay station maintains the same preamble and broadcast timing during handover, then synchronization between relay station and mobile stations is maintained, but interference occurs between preambles and broadcasts from different base stations

Engineering Contradiction:

Improvesynchronization between relay station and mobile stationsVSAvoidinterference between preambles and broadcasts

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The relay station receives handover indication information from the source base station before performing handover, allowing it to prepare timing adjustments in advance. The relay station calculates the timing difference between source and target base stations and adjusts its preamble and broadcast timing accordingly before the handover is complete, preventing both synchronization loss and interference.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The relay station dynamically changes its preamble and broadcast timing parameters based on the handover process. By adjusting the timing offset according to the target base station's schedule, the relay station maintains synchronization with mobile stations while avoiding interference with transmissions from other base stations.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If the relay station performs handover between base stations, then the relay station can maintain connectivity with the network, but synchronization with mobile stations is lost causing communication disruption

Engineering Contradiction:

Improvehandover capability of relay stationVSAvoidsynchronization between relay station and mobile stations

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The relay station receives handover indication information from the source base station before performing handover, allowing it to prepare timing adjustments in advance. The relay station calculates the timing difference between source and target base stations and adjusts its preamble and broadcast timing accordingly before the handover is complete, preventing both synchronization loss and interference.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The relay station continuously monitors the timing relationship between base station transmissions and its own transmissions. By using feedback from timing advance commands and handover indication information, the relay station adjusts its timing to maintain synchronization with mobile stations while adapting to changes in the network topology during handover.

Inventive Principle:

Principle #23Feedback

3Reliability

If mobile stations lose synchronization during relay station handover, then communication disruption occurs, but recovery process consumes radio resources creating overhead

Engineering Contradiction:

Improvecommunication continuityVSAvoidradio resources consumed for synchronization recovery

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The relay station receives handover indication information from the source base station before performing handover, allowing it to prepare timing adjustments in advance. The relay station calculates the timing difference between source and target base stations and adjusts its preamble and broadcast timing accordingly before the handover is complete, preventing both synchronization loss and interference.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The relay station proactively adjusts its timing parameters in anticipation of potential synchronization loss during handover. By pre-calculating and applying timing offsets based on handover indication information, the relay station prevents synchronization disruption before it occurs, eliminating the need for resource-intensive recovery processes.

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS8095160B2Intermediate station and method for facilitating handover in a multi-hop communication system

Publication Date: 2012.01.10 MOTOROLA SOLUTIONS INC

AI summary

An intermediate station and method for facilitating handover in a multi-hop communications system is disclosed. The method may include receiving a handover trigger, finding a target station to receive handover, determining whether the handover requires a timing change, wherein if it is determined that a preamble and broadcast timing change for one or more downstream stations is required, estimating when the handover will take place, instructing the one or more downstream stations to resynchronize, and performing the handover to the target station.