Uplink Power Control for Shortened Transmission Time Intervals
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently calculating uplink transmit power for aperiodic channel state information (CSI) reports within shortened transmission time intervals (sTTIs), particularly due to dependencies on the actual number of CQI/PMI bits, which can exceed processing time limits in low latency communications.
Innovation Solution
The method decouples CSI processing and uplink power calculation by using a predetermined or maximum number of CQI/PMI bits to determine the bits per resource element (BPRE) parameter, allowing independent calculation of transmit power for aperiodic CSI reports, even in the absence of uplink data, and transmitting these reports in the physical uplink shared channel (PUSCH).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the actual number of CQI/PMI bits is used to calculate transmit power for aperiodic CSI reports, then the transmit power calculation is accurate, but the processing time exceeds the timing requirements of shortened TTI operations
Solution Approach 1:
The patent applies preliminary action by pre-determining the number of CQI/PMI bits based on maximum possible values or configured parameters before the actual CSI processing is complete. This allows the transmit power calculation to proceed in advance without waiting for the final CSI payload determination, thereby resolving the timing conflict while maintaining sufficient calculation accuracy through conservative bit count assumptions.
2Reliability
If the transmit power calculation waits for actual CSI processing to complete, then the power calculation is precise, but it cannot meet the stringent timing requirements of sTTI operations
Solution Approach 1:
The patent performs preliminary transmit power calculations using configured parameters and maximum bit assumptions before actual CSI processing completes. This preliminary action ensures that power allocation is determined in time for sTTI operations while maintaining reliability through conservative estimates that can be adjusted if needed, thus balancing precision requirements with productivity demands.
Solution Approach 2:
The patent uses simplified, approximate bit count assumptions (such as maximum possible values) that are computationally inexpensive and do not require waiting for complete CSI processing. These approximate calculations serve as sufficient substitutes for precise calculations in time-critical scenarios, enabling fast processing without significantly compromising system performance.
3Productivity
If independent transmit power calculation is implemented for aperiodic CSI reports, then timing requirements are met, but dependency on actual CSI payload information is reduced
Solution Approach 1:
The patent extracts the transmit power calculation process from the actual CSI payload processing dependency. By separating the power calculation timing from the CSI completion timing and using independent parameter-based calculations, the system achieves processing efficiency gains while the loss of payload information dependency is acceptable because the power calculation uses sufficient approximations based on maximum bit assumptions and configured parameters.
Data Source
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AI summary
Certain aspects of the present disclosure relate to methods and apparatuses for power control of transmissions on a physical uplink shared channel (PUSCH) with shortened transmission time intervals (sTTIs). According to certain aspects, a UE may calculate a transmit power for an aperiodic channel state information (A-CSI) report that is independent of an actual number of channel quality indicator (CQI) and precoding matrix indicator (PMI) bits to transmit in the A-CSI report. The UE may then transmit the A-CSI report in accordance with the calculated transmit power.