ROHC Reset Indicator in PDCP Header for Handover
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Solution Overview
Problem
Current wireless communication systems face challenges in maintaining seamless data transmission during simultaneous connectivity handover between cells, particularly in LTE and NR networks, due to issues with robust header compression (ROHC) decompression after a path switch, where legacy implementations fail to provide a clear indication for resetting ROHC, leading to packet decompression failures.
Innovation Solution
Incorporating a single bit ROHC reset indicator in the PDCP header or a new PDCP control PDU to indicate when ROHC should be reset during handover, ensuring uninterrupted data flow by synchronizing decompression across source and target cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If legacy ROHC implementation is used during handover, then device complexity is reduced, but packet decompression reliability deteriorates due to failures after path switch
Solution Approach 1:
The patent applies preliminary action by resetting the ROHC decompression state at the UE before the path switch completes, based on receiving an indication from the target cell. This proactive reset prevents decompression failures that would occur if the old compression state from the source cell is used after handover, thereby improving packet decompression reliability without adding complex post-handover detection mechanisms.
2Reliability
If ROHC reset indication is added to PDCP header, then decompression reliability is improved, but header processing complexity increases
Solution Approach 1:
The patent extracts the ROHC reset indication as a separate, dedicated field within the existing PDCP header structure. By taking out this specific signaling function and placing it in a predetermined location in the header, the patent enables reliable ROHC state management during handover while keeping the processing complexity minimal, as the indication can be detected through simple field examination without complex parsing.
3Productivity
If simultaneous connectivity handover is implemented, then service continuity is improved, but data transmission reliability deteriorates due to ROHC decompression failures
Solution Approach 1:
The patent implements feedback by having the target cell send an explicit indication to the UE about whether to reset ROHC decompression after handover. This feedback mechanism allows the network to control the ROHC state synchronization between source and target cells, ensuring that the UE uses the correct compression state for data received from the target cell, thereby maintaining data transmission reliability during simultaneous connectivity handover.
Data Source
AI summary
Systems, methods, and devices are provided to: perform packet data convergence protocol (PDCP) deciphering of the packets to store deciphered packets in a common buffer; perform PDCP reordering of the deciphered packets in the common buffer to generated a stream or reordered packets; perform robust header compression (ROHC) decompression on the stream of reordered packets; and determine, based on a packet indication, to reset the ROHC decompression, wherein the packet indication comprises a single bit in a PDCP header set to indicate a start of ROHC reset based on a path switch during a handover from a source cell to a target cell.