5G Uplink Path-Loss Tracking with Pre-Activated Reference Signals
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Solution Overview
Problem
Current methods for tracking reference signal path losses in uplink transmissions in 5G wireless communication networks suffer from mismatches in beam and path-loss RS indications, leading to incorrect power compensation and degraded UL signal quality due to long latency in updating path-loss RS estimates.
Innovation Solution
Implement mechanisms for pre-activating and tracking multiple path-loss RSs in advance, using priority rules to manage RSs beyond UE capability, and associating path-loss estimates with UL signals to synchronize beam and power compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current MAC-CE based path-loss RS update techniques are used, then path-loss RS can be updated, but the update latency is long (approximately 100 ms) causing mismatch between spatial relation and path-loss RS indications
Solution Approach 1:
The patent applies preliminary action by having the UE pre-activate and track multiple path-loss reference signals before they are actually needed for uplink transmission. The UE maintains a set of activated path-loss RSs and continuously measures their reference signal received power (RSRP), so when a new path-loss RS needs to be applied, the measurement and processing is already complete or near-complete, eliminating the 100ms latency issue.
Solution Approach 2:
The patent segments the path-loss RS tracking process into multiple parallel tracks, each dedicated to a specific path-loss reference signal. The UE can simultaneously track multiple path-loss RSs (e.g., first path-loss RS, second path-loss RS, third path-loss RS) in parallel, allowing the system to prepare multiple path-loss estimates concurrently rather than sequentially, thus reducing overall update latency.
2Loss of time
If multiple path-loss RSs are tracked simultaneously, then update latency is reduced, but the UE capability is exceeded when more RSs than supported are activated
Solution Approach 1:
The patent implements dynamics by making the set of activated path-loss RSs configurable and adaptable. The network can dynamically adjust which path-loss RSs are activated based on current transmission conditions, and the UE can flexibly manage its resources by activating only the necessary number of path-loss RSs (up to its capability limit) rather than maintaining a fixed large set always.
Solution Approach 2:
The patent applies partial action by allowing the UE to track only the necessary number of path-loss RSs up to its capability limit rather than requiring full tracking of all possible RSs. The system activates path-loss RSs partially based on actual transmission needs, and when more than the UE's capability are available, it selectively activates the appropriate subset.
3Measurement precision
If path-loss RS estimates are applied with standard timing (ACK + 3ms + X measurements + 2ms), then measurement accuracy is maintained, but closed loop UL transmission accumulates errors based on mismatched path-loss RS
Solution Approach 1:
The patent applies preliminary action by having the UE pre-activate and continuously measure multiple path-loss reference signals before they are needed for uplink transmission. The UE maintains a set of activated path-loss RSs and continuously measures their reference signal received power (RSRP), so when a new path-loss RS needs to be applied, the measurement and processing is already complete or near-complete, eliminating the 100ms latency issue.
Solution Approach 2:
The patent implements feedback mechanisms where the UE reports the measured RSRP values of activated path-loss RSs to the network, and the network uses this feedback information to determine appropriate path-loss compensation values. This closed-loop feedback ensures that the path-loss estimates are continuously updated and accurate, preventing accumulation of transmission errors.
Data Source
AI summary
Methods and systems for controlling a transmit power of a wireless communication device are disclosed herein. In one embodiment, a method includes: determining one or more reference signals transmitted by a wireless communication node; maintaining one or more path loss estimates for the one or more reference signals; associating at least one path loss estimate with an uplink (UL) signal; calculating a transmission power of the UL signal according to the at least one path loss estimate; and transmitting the UL signal in accordance with the calculated transmission power.