Node B Combining Capability Signaling for HSUPA Soft Handover
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Solution Overview
Problem
In 3G mobile wireless communications, Node B's combining capabilities for uplink enhanced dedicated channels are not known to serving radio network controllers, limiting soft handover gains as UE can only use one combining method, and existing technologies do not effectively communicate these capabilities during cell setup or soft handover.
Innovation Solution
A method and system for providing combining capability information of a Node B to radio network controllers using signaling, specifically supporting incremental redundancy and Chase combining, through Node B Application Part (NBAP) and Radio Network Subsystem Application Part (RNSAP) messages, allowing CRNC and SRNC to configure appropriate combining methods for HSUPA communications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Node B supports multiple combining methods (IR and Chase combining), then combining capability is improved, but the SRNC does not know which combining method the Node B will execute, limiting soft handover gains
Solution Approach 1:
The solution segments the information flow by introducing separate signaling paths: NBAP messages for Node B to CRNC communication, and RNSAP messages for CRNC to SRNC communication. This segmentation allows combining capability information to be transmitted through specific channels without interfering with other control signals, resolving the information loss problem while maintaining multi-combining support.
Solution Approach 2:
The CRNC acts as an intermediary between Node B and SRNC. The Node B first signals its combining capabilities to the CRNC via NBAP messages, and then the CRNC forwards this information to the SRNC via RNSAP messages. This intermediary mechanism ensures that the SRNC receives accurate combining capability information without requiring direct Node B-SRNC signaling, thus preserving information while enabling multi-combining versatility.
2Device complexity
If the UE can only use one combining method during soft handover, then device complexity is reduced, but soft handover gains are limited
Solution Approach 1:
The solution introduces dynamic combining method selection where the SRNC can indicate which combining method the Node B should execute during soft handover. The SRNC receives combining capability information from the CRNC, determines the appropriate combining method based on current conditions, and signals this selection back to the Node B. This dynamic approach allows the system to optimize for soft handover performance while keeping UE implementation complexity manageable through centralized control.
3Productivity
If the SRNC indicates which combining the Node B should execute, then combining efficiency is improved, but the Node B's inherent capabilities are not fully utilized
Solution Approach 1:
The solution implements preliminary action by having the Node B pre-signal its combining capabilities to the CRNC before actual data transmission begins. This advance notification allows the SRNC to make informed decisions about which combining method to use during soft handover, optimizing combining efficiency without restricting the Node B's inherent capabilities. The Node B maintains support for multiple combining methods but receives guidance on which to use in specific situations.
Data Source
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AI summary
The specification and drawings present a new method, system, apparatus and software product for providing combining capability information of a Node B (supporting a cell to which a user equipment is set-up) to radio network controllers as related to HSUPA (High Speed Uplink Packet Access). The Node B can support among others, e.g., incremental redundancy (IR) combining and/or Chase combining. Furthermore, the combining capability information of the node B can be, e.g., for combining data received on an uplink enhanced dedicated channel (E-DCH).