ROHC Parameter Handling for Seamless Wireless Handover
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Solution Overview
Problem
In wireless communication systems, inter Access Service Network Gateway (ASN-GW) handovers often fail due to differences in Robust Header Compression (ROHC) capabilities and resource-intensive context information exchange, leading to communication breakdowns between ASN-GWs with varying ROHC parameters.
Innovation Solution
A method where the ASN-GW receives ROHC parameter information from the previous ASN-GW during a handover and uses a dynamic service change request message to transmit and reset ROHC parameters, allowing seamless communication between ASN-GWs with different ROHC capabilities without exchanging context information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the serving ASN-GW transmits context information to the target ASN-GW during inter ASN-GW handover, then the target ASN-GW can restore ROHC communication with the MS, but the handover fails when ASN-GWs have different ROHC capabilities due to incompatible parameters
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting ROHC parameters at the target ASN-GW based on its own capabilities rather than using parameters received from the serving ASN-GW. When the target ASN-GW receives context information, it detects parameter incompatibility and initiates a parameter re-negotiation process, sending a dynamic service change request message to the MS with updated parameters that are compatible with both the target ASN-GW and the MS capabilities.
2Loss of information
If the serving ASN-GW transmits context information in IP packet format during handover, then the target ASN-GW receives complete ROHC parameters, but the serving ASN-GW exhausts its resources and fails to transmit the context information
Solution Approach 1:
The patent extracts only the essential ROHC parameter information from the complete context information and transmits a simplified version to the target ASN-GW. Instead of transmitting the entire context information structure, the serving ASN-GW extracts and sends only the critical parameters needed for ROHC communication, significantly reducing the resource burden while maintaining the ability to restore communication at the target side.
3Ease of operation
If the target ASN-GW uses ROHC parameters received from the serving ASN-GW, then the handover process is simple, but communication fails when the parameters are incompatible with the target ASN-GW's ROHC capabilities
Solution Approach 1:
The patent implements feedback by having the target ASN-GW detect parameter incompatibility and send a dynamic service change request message back to the MS with corrected parameters. This feedback mechanism allows the system to automatically detect and correct parameter incompatibility issues, ensuring reliable communication while maintaining a relatively simple handover process through automated parameter adjustment.
Data Source
AI summary
A system and method support robust header compression (ROHC) for a mobile station (MS) handover in a wireless communication system. If a mobile station (MS) accesses a base station (BS) controlled by the ASN-GW through a handover, ROHC parameter information is received from a previous ASN-GW controlling a previous BS accessed by the MS before the handover. An ROHC parameter for ROHC-based communication with the MS is determined on the basis of the ROHC parameter information received from the previous ASN-GW. The determined ROHC parameter is transmitted to the MS by using a path modification request message for an ROHC service flow.