Dynamic Uplink Power Control via TP-Specific Reference Signals
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Solution Overview
Problem
In LTE networks, user equipment (UE) often transmits at higher power levels than necessary, leading to wasted energy and increased network interference due to inaccurate path loss estimates based on cell-specific reference signals (CRS), which do not account for the unique channel quality between the UE and individual remote radio heads (RRHs).
Innovation Solution
Implementing a method for dynamic switching between TP-common and TP-specific transmission modes, using CSI-RS-based path loss estimates to determine the optimal transmission power for each RRH, allowing UEs to transmit at lower power levels while maintaining connectivity with specific RRHs, thereby reducing power consumption and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UE uses cell-specific reference signals (CRS) for path loss estimation, then connectivity is maintained with all transmission points, but transmit power is higher than necessary and network interference increases
Solution Approach 1:
The patent segments the reference signal functionality by introducing transmission point-specific reference signals (TP-CSI-RS) alongside cell-specific reference signals (CRS). Each TP-CSI-RS is associated with a specific transmission point and provides path loss estimation tailored to that TP, allowing the UE to differentiate between broad connectivity maintenance and optimized power control for individual TPs.
Solution Approach 2:
The patent applies local quality by providing UE-specific, TP-specific reference signals that deliver localized channel quality information. Each TP-CSI-RS is configured with UE-specific parameters and provides path loss estimation specific to the channel between the UE and that particular TP, enabling localized power control decisions rather than using a single cell-wide CRS for all TPs.
2Reliability
If UE transmits at higher power levels to ensure connectivity, then connection reliability is improved, but battery consumption increases and network interference worsens
Solution Approach 1:
The patent implements feedback mechanisms where the UE measures channel quality using TP-CSI-RS, estimates path loss specific to each TP, and adjusts its uplink transmit power accordingly. The network receives channel quality feedback from the UE and can provide power control commands to optimize UE transmit power based on actual channel conditions to each TP, creating a closed-loop system that balances reliability and energy efficiency.
Solution Approach 2:
The patent introduces dynamic power control by allowing the UE to switch between different reference signal types (CRS and TP-CSI-RS) and adjust transmit power dynamically based on which TPs are currently serving the UE. The system can adaptively change power levels as the UE moves or as network conditions change, rather than using a static high power level for all conditions.
3Adaptability or versatility
If UE uses cell-specific reference signals for path loss estimation, then compatibility with existing LTE infrastructure is maintained, but path loss estimation accuracy for individual RRHs is insufficient
Solution Approach 1:
The patent achieves universality by designing TP-CSI-RS to work within the existing LTE framework while adding new functionality. The TP-CSI-RS uses the same basic signal structure and processing as traditional CRS, ensuring backward compatibility with existing LTE infrastructure. However, it extends functionality by being configurable per transmission point and per UE, enabling accurate TP-specific path loss estimation without replacing the entire reference signal system.
Data Source
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AI summary
Dynamic switching of uplink power control and synchronization in wireless networks involves switching a user equipment (UE) from a transmission point common (TP-common) mode to a transmission point specific (TP-specific) mode in a wireless network. The UE transmits at a high power level in a TP-common mode to compensate for a larger path loss between the UE and the TPs and at a low power level in a TP-specific mode to save battery power based on a smaller path loss between the UE and a specific, nearby TP.