Radio Network Controller Transmit Power Control Optimization
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Solution Overview
Problem
Current wireless communication systems face challenges in reducing transmit power control frequency, leading to inefficiencies in energy usage and capacity, particularly in compressed mode operations and when multiple users share the same Fractional-Dedicated Physical Channel (F-DPCH) resources.
Innovation Solution
A method is introduced where a decimation factor is determined for a transmit power control algorithm, allowing transmit power control commands to be discontinuously transmitted, with specific patterns and rules for generating additional commands in non-transmission slots to optimize power control, enabling more efficient use of resources and increased capacity by allowing multiple users to share the same F-DPCH channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If transmit power control frequency is reduced to save energy and increase capacity, then energy efficiency and system capacity improve, but power control accuracy and link reliability deteriorate
Solution Approach 1:
The patent applies preliminary action by predicting future power control commands based on historical TPC command patterns and channel conditions. The network node generates predicted TPC commands in advance for slots where actual TPC commands are not transmitted, allowing the UE to maintain accurate power control despite reduced TPC transmission frequency. This prediction mechanism compensates for the reduced control accuracy that would normally result from less frequent TPC updates.
Solution Approach 2:
The patent implements feedback mechanisms where the UE monitors downlink channel quality and compares actual channel conditions against predicted conditions. When significant deviations are detected, the system adjusts the prediction algorithm or increases TPC transmission frequency. This feedback loop ensures that power control accuracy is maintained dynamically, adapting to changing channel conditions while preserving the energy savings from reduced TPC frequency.
2Quantity of substance
If transmit power control frequency is reduced to increase system capacity, then more users can share F-DPCH resources, but control responsiveness and link adaptation worsen
Solution Approach 1:
The network node performs preliminary analysis of channel conditions and traffic patterns to predict future power control requirements. By generating predicted TPC commands in advance and storing them for later transmission, the system can serve more users on F-DPCH without sacrificing control responsiveness. The prediction buffer allows the system to quickly respond to channel changes when TPC transmission opportunities arise, maintaining control speed while increasing overall system capacity.
Solution Approach 2:
The patent implements periodic TPC command transmission with optimized timing patterns. Instead of continuous TPC transmission, the system transmits TPC commands periodically at strategically selected intervals based on channel coherence time and user activity patterns. This periodic approach increases system capacity by reducing control channel overhead while maintaining responsiveness through careful timing selection that aligns with channel characteristics and traffic dynamics.
3Loss of energy
If discontinuous transmit power control commands are transmitted to save energy, then energy consumption decreases, but power control stability and signal quality deteriorate
Solution Approach 1:
The network node performs preliminary power control calculations based on historical channel measurements and predicted traffic conditions. By computing predicted TPC commands in advance and maintaining a buffer of pre-calculated power control adjustments, the system ensures stable power control continuity even when actual TPC transmissions are discontinuous. This preliminary computation prevents power control instability that would otherwise result from gaps in TPC command transmission.
Solution Approach 2:
The patent dynamically adjusts TPC transmission parameters including frequency, timing, and command aggregation based on channel conditions and user requirements. When channels are stable, the system reduces TPC frequency to save energy. When channels become more variable, the system increases TPC frequency or adjusts prediction intervals to maintain stability. This adaptive parameter changing allows the system to optimize energy consumption while preserving power control stability under varying conditions.
Data Source
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AI summary
A method in a radio network controller (130) is disclosed. The method comprises determining (1204) a decimation factor for a transmit power control (TPC) algorithm, the TPC algorithm comprising a power control algorithm according to which TPC commands for controlling a transmit power of a wireless device (110) are discontinuously transmitted to the wireless device by a network node (115), the decimation factor indicating a predefined number of slots, wherein one out of the predefined number of slots is for transmitting a TPC command to the wireless device; upon determining the decimation factor for the TPC algorithm, modifying (1208) one or more parameters related to TPC to optimize TPC using the TPC algorithm having the determined decimation factor; and configuring (1212) the network node to control the transmit power of the wireless device according to the TPC algorithm and the one or more modified parameters.