Multi-Antenna Uplink Power Control for LTE-Advanced
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Solution Overview
Problem
Current techniques for uplink power control in communications systems with multiple transmit antennas are not optimal, as they extend existing single antenna power control schemes, which do not provide effective results in multiple transmit antenna situations, especially in LTE-Advanced systems that support multiple layer/multiple codeword transmissions.
Innovation Solution
A system and method for determining and setting transmit power levels for each transmit antenna in user equipment (UE) with multiple antennas, considering the sum of transmit powers, allowing per-antenna, per-layer, or per-codeword power control, and incorporating transmission format considerations to optimize power control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If existing single transmit antenna power control schemes are extended to multiple transmit antennas, then device complexity is reduced, but power control performance deteriorates
Solution Approach 1:
The patent segments the power control problem into multiple independent control dimensions: per-antenna power control, per-layer power control, and per-codeword power control. This segmentation allows the system to apply appropriate control granularity to different transmission scenarios, improving performance without requiring complete redesign of the power control architecture.
Solution Approach 2:
The patent introduces new control dimensions beyond simple antenna count. Instead of treating power control as a single-dimensional problem (total power allocation), it adds dimensions of antenna-specific control, layer-specific control, and codeword-specific control, creating a multi-dimensional power control framework that better handles MIMO complexity.
2Reliability
If per-antenna power control is implemented for multiple transmit antennas, then power control performance is improved, but device complexity increases
Solution Approach 1:
The patent implements dynamic power control where the control granularity (per-antenna, per-layer, or per-codeword) can be adapted based on transmission conditions. The system dynamically selects the appropriate control mode depending on the number of antennas, layers, and codewords being used, avoiding unnecessary complexity in scenarios where simpler control suffices.
Solution Approach 2:
The patent applies different power control strategies to different parts of the transmission system based on local requirements. Per-antenna control is applied when antenna-specific channel conditions differ significantly, while per-layer or per-codeword control is used when the bottleneck is in the data stream rather than the physical antenna characteristics.
3Reliability
If transmit power level is increased to improve uplink performance, then uplink performance is improved, but battery life deteriorates and interference increases
Solution Approach 1:
The patent changes the power allocation parameters from a single total power value to multiple distributed power values across antennas, layers, and codewords. This parameter transformation enables more efficient power distribution, achieving the same uplink performance with lower total power consumption by directing power to the most effective transmission paths.
Solution Approach 2:
The patent extracts and controls power allocation at multiple levels (antenna level, layer level, codeword level) rather than treating power as a single aggregate resource. This extraction allows the system to identify and eliminate inefficient power usage in specific dimensions while maintaining overall performance.
4Reliability
If transmit power level is increased to improve uplink performance, then uplink performance is improved, but interference to other devices increases
Solution Approach 1:
The patent applies local quality control by allocating power differently across spatial (antennas) and data (layers/codewords) dimensions based on local channel conditions. This localized power optimization reduces interference to other devices by concentrating power on the most effective transmission paths rather than uniformly increasing power across all dimensions.
Solution Approach 2:
The patent applies partial power allocation to specific antennas, layers, or codewords based on their individual needs rather than uniformly increasing power. This partial action approach achieves the necessary uplink performance improvement while avoiding excessive power consumption and interference that would result from blanket power increases.
Data Source
AI summary
A system and method for uplink multi-antenna power control in a communications system are provided. A method for user equipment operations includes determining a transmit power level for transmit antennas of the user equipment having at least two transmit antennas, and setting a power amplifier output level for each of the at least two transmit antennas in accordance with a respective transmit power level.