SRS Carrier Switching Power Control Adaptation
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Solution Overview
Problem
Current uplink power control accuracy for sounding reference signals (SRS) is compromised during carrier-based switching in LTE networks, particularly due to transmission gaps and the use of listen-before-talk (LBT) procedures, which can lead to inadequate power control when switching between carriers, especially in scenarios with multiple SRS carrier switching operations.
Innovation Solution
Adapting uplink power control parameters, such as transmission gap parameters, to meet absolute or relative power control requirements based on the transmission gap length, and considering the use of LBT procedures, to ensure accurate power control during SRS carrier-based switching across multiple carriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If SRS carrier-based switching is performed in LTE networks, then channel estimation accuracy for uplink scheduling and link adaptation is improved, but uplink power control accuracy deteriorates due to transmission gaps and LBT procedures
Solution Approach 1:
The patent changes the transmission gap parameter from a fixed value to a configurable parameter that can be adjusted based on the number of SRS carrier switching operations. When multiple SRS carrier switching operations are detected, the transmission gap is extended to ensure sufficient time for power control adjustments, thereby maintaining power control accuracy while enabling accurate channel estimation through SRS transmissions
2Manufacturing precision
If transmission gap is extended to accommodate multiple SRS carrier switching operations, then uplink power control accuracy is maintained, but transmission time and system productivity deteriorate
Solution Approach 1:
The patent implements a dynamic transmission gap adjustment mechanism where the gap duration is not fixed but adapts based on the detected number of SRS carrier switching operations. The network device configures different transmission gap values dynamically: shorter gaps when switching operations are minimal, and extended gaps when multiple switching operations occur, thereby optimizing the balance between power control accuracy and system productivity
Solution Approach 2:
The transmission gap parameter is changed from a static configuration to a dynamic parameter that varies according to channel conditions and switching operation frequency. This parameter adaptation allows the system to maintain power control accuracy only when necessary (during multiple switching operations) while using shorter gaps during normal operations, thus preserving system productivity
3Adaptability or versatility
If multiple SRS carrier switching operations are performed, then channel reciprocity utilization is improved for TDD networks, but transmission gap length increases leading to power control inaccuracies
Solution Approach 1:
The patent applies preliminary action by having the network device detect and count SRS carrier switching operations before configuring the transmission gap. Based on this preliminary detection, the network proactively configures an appropriate transmission gap value that prevents power control inaccuracies from occurring in the first place, rather than attempting to correct them afterward
Data Source
AI summary
According to some embodiments, a method for use in a user equipment (UE) operable to transmit a sounding reference signal (SRS) on a plurality of carriers comprises: obtaining an indication to perform SRS carrier-based switching for a carrier; adapting a parameter for uplink transmit power control in response to the obtained indication; and transmitting an uplink signal using the adapted parameter while meeting at least one predetermined uplink power control requirement. According to some embodiments, a method for use in a network node operable to receive a SRS on a plurality of carriers comprises: sending, to a UE, an indication to perform SRS carrier-based switching for a carrier; and receiving, from the UE, an uplink signal based on the parameter for uplink transmit power control adapted in response to the sent indication, wherein the uplink signal meets at least one uplink power control requirement.