Dynamic Interlaced FDM Uplink DMRS Configuration
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Solution Overview
Problem
Current wireless communication systems face interference challenges in uplink transmissions due to shared network resources, especially in multi-user MIMO environments, where existing DMRS configurations struggle with maintaining orthogonality and efficiency, particularly with the deployment of higher-order antenna arrays and reduced RB allocations.
Innovation Solution
The method involves dynamically configuring uplink DMRS transmission using either SC-FDM or IFDM configurations based on indications from the serving base station, utilizing a dynamic indication mechanism such as DCI formats or RB assignments to select between SC-FDM and IFDM, and applying specific OCC and CS combinations to maintain orthogonality and support multiple users.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If SC-FDM configuration is used for uplink DMRS transmission, then device complexity is reduced and ease of operation is improved, but orthogonality and interference management deteriorate in multi-user MIMO environments
Solution Approach 1:
The patent implements dynamic configuration switching between SC-FDM and IFDM modes based on network conditions, user equipment capabilities, and interference levels. The base station receives capability indicators from UEs and dynamically selects the appropriate DMRS configuration mode, allowing the system to adapt between simplicity (SC-FDM) and performance (IFDM) as needed.
Solution Approach 2:
The patent changes the fundamental parameter of DMRS configuration mode from fixed to variable, allowing switching between SC-FDM (continuous frequency allocation) and IFDM (interleaved frequency allocation). This parameter change enables the system to optimize orthogonality maintenance through IFDM's interleaved structure when needed, while retaining SC-FDM's operational simplicity when appropriate.
2Reliability
If IFDM configuration is used for uplink DMRS transmission, then orthogonality and interference management are improved, but device complexity increases
Solution Approach 1:
The patent makes the DMRS configuration dynamic rather than static, allowing the system to switch between SC-FDM and IFDM modes based on actual network conditions, UE capabilities, and interference levels. This dynamic approach ensures that the increased complexity of IFDM is only incurred when necessary for maintaining orthogonality, rather than being permanently required.
Solution Approach 2:
The patent introduces a configurable parameter that allows switching between two distinct DMRS configuration modes. The IFDM mode with its interleaved frequency allocation and enhanced orthogonality properties is activated only when the system determines it is needed, thereby managing device complexity by avoiding unnecessary complexity in scenarios where SC-FDM suffices.
3Adaptability or versatility
If dynamic indication mechanism is implemented to select between SC-FDM and IFDM, then adaptability to varying network conditions is improved, but signaling overhead and device complexity increase
Solution Approach 1:
The patent implements a dynamic indication mechanism where the base station receives capability indicators from UEs and dynamically selects between SC-FDM and IFDM configurations. This dynamic selection process enables the system to adapt to varying network conditions, UE capabilities, and interference levels while managing complexity through automated decision-making rather than manual configuration.
Solution Approach 2:
The patent incorporates a feedback loop where UEs provide capability indicators to the base station, which then determines the appropriate DMRS configuration mode. This feedback mechanism enables adaptive configuration selection based on actual UE capabilities and network conditions, improving versatility while managing complexity through structured information exchange rather than trial-and-error approaches.
Data Source
AI summary
Signaling design for interlaced frequency divisional multiplex (IFDM) demodulation reference signals (DMRS) is discussed in which a dynamic indication is provided to a user equipment (UE) from a serving base station that allows the UE to configure transmission of DMRS according to either a single carrier frequency divisional multiplex (SC-FDM) or IFDM configurations, as indicated by the dynamic indication. The IFDM configuration may be applicable to either regular uplink subframes or within the uplink portion of special subframes. In some aspects, power boosting may be provided for the DMRS in order to equalize transmit power between decimated DMRS transmitted with the data tones. Additional aspects may also provide for different offsets to be used depending on the type of uplink control signal transmitted.