Cross-Carrier Uplink Scheduling for TDM Carrier Aggregation
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently scheduling uplink transmissions across multiple component carriers in time division multiplexing (TDM) carrier aggregation, particularly in inter-band carrier aggregation scenarios involving TDD and FDD modes, which can lead to interruptions in uplink SPS configurations and configured grants.
Innovation Solution
The proposed solution involves configuring a cross-carrier uplink transmission pattern that takes into account reserved uplink resources, Specific Absorption Rate (SAR) requirements, and the specific characteristics of TDD and FDD modes. This is achieved through RRC signaling and DCI messages that activate uplink SPS configurations and configured grants, ensuring seamless operation across multiple carriers while adhering to SAR limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If uplink transmissions are scheduled across multiple component carriers in TDM carrier aggregation, then spectral efficiency and network capacity are improved, but interruptions in uplink SPS configurations and configured grants occur
Solution Approach 1:
The patent implements dynamic switching between self-scheduling and cross-carrier scheduling modes based on real-time channel conditions and traffic requirements. The network can flexibly adjust the scheduling mode for different component carriers and different time periods, optimizing both spectral efficiency and transmission reliability by adapting to changing conditions rather than using a fixed scheduling approach
Solution Approach 2:
The patent introduces a scheduling entity (base station) that acts as an intermediary to coordinate uplink transmissions across multiple component carriers. This scheduling entity manages the timing and resource allocation to prevent collisions and interruptions, ensuring that SPS configurations and configured grants maintain continuity while still enabling multi-carrier operation
2Adaptability or versatility
If multiple scheduling messages are used for each component carrier, then scheduling flexibility is improved, but signaling overhead and system complexity increase
Solution Approach 1:
The patent employs a universal scheduling mechanism where a single scheduling entity can manage multiple component carriers with different scheduling modes (self-scheduling and cross-carrier scheduling). The scheduling entity uses unified signaling structures that can adapt to different carrier configurations, reducing overall system complexity while maintaining the flexibility to optimize each carrier independently based on its specific requirements
Solution Approach 2:
The patent segments the scheduling function into different modes (self-scheduling for some carriers, cross-carrier scheduling for others) and different time periods. This segmentation allows the system to apply the appropriate scheduling complexity only where needed, reducing overall signaling overhead while maintaining necessary flexibility for specific carriers or traffic types
3Productivity
If uplink transmissions are performed on multiple component carriers simultaneously, then data rate is improved, but SAR requirements may be violated
Solution Approach 1:
The patent implements periodic monitoring and adjustment of uplink transmission patterns across component carriers to ensure SAR compliance. The system periodically evaluates the cumulative power exposure and dynamically adjusts the timing and power distribution of uplink transmissions, allowing high data rates during periods when SAR limits are not exceeded while maintaining compliance over time
Solution Approach 2:
The patent dynamically changes transmission parameters (power levels, timing offsets, active carrier selection) based on real-time SAR assessments. When SAR thresholds approach limits, the system adjusts parameters to reduce exposure while maintaining acceptable data rates, and when margins are available, it increases transmission aggressiveness to maximize throughput
Data Source
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AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a base station may configure an uplink transmission pattern related to an uplink transmission resource on multiple component carriers. The base station may transmit, to a user equipment (UE), information related to activating the uplink transmission pattern in a single scheduling message. Accordingly, the UE may transmit information on the multiple component carriers in one or more uplink symbols based at least in part on the uplink transmission pattern. Numerous other aspects are provided.