Aperiodic Uplink Power Control for LTE Overhead Reduction
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Solution Overview
Problem
In Long Term Evolution (LTE) based wireless communication systems, existing power control methods face challenges in efficiently adjusting uplink power levels to maintain optimal signal-to-noise ratios and minimize overhead, especially in scenarios with multiple access terminals transmitting in proximity, where path loss, shadowing, and interference vary.
Innovation Solution
The implementation of aperiodic closed loop power control corrections, which allow for single-bit or multi-bit adjustments of uplink power levels via layer 1/layer 2 control information channels, triggered by measurements or opportunities for transmission, in conjunction with periodic power control mechanisms to dynamically adjust uplink power levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If periodic power control commands are transmitted to all access terminals, then uplink power levels are maintained within acceptable ranges, but transmission overhead increases significantly
Solution Approach 1:
The patent changes the transmission parameter from periodic to aperiodic, sending power control commands only when necessary based on measured conditions. This reduces the frequency of transmissions while maintaining power level reliability, directly addressing the overhead problem.
Solution Approach 2:
The system uses measurements from the network side to trigger commands only when power adjustments are actually needed, rather than sending commands on a fixed schedule. This self-regulating approach reduces unnecessary transmissions while maintaining reliable power control.
2Loss of information
If aperiodic power control commands are transmitted only when needed, then transmission overhead is reduced, but response time to power level deviations may increase
Solution Approach 1:
The patent implements a feedback mechanism where the network continuously measures uplink power levels and triggers aperiodic commands when deviations are detected. This ensures timely response to power level changes while avoiding unnecessary periodic transmissions, balancing response time and overhead.
Solution Approach 2:
The system dynamically adjusts the transmission timing of power control commands based on actual network conditions rather than following a fixed periodic schedule. This dynamic approach allows immediate response when power adjustments are needed while reducing overhead during stable conditions.
3Measurement precision
If multi-bit power control corrections are implemented, then power adjustment precision is improved, but command transmission overhead increases
Solution Approach 1:
The patent uses multi-bit corrections (excessive action) only when large power adjustments are needed, while using single-bit corrections for smaller adjustments. This selective approach achieves necessary precision without always incurring the maximum overhead of multi-bit commands.
Solution Approach 2:
The system changes the correction parameter size (single-bit vs multi-bit) based on the magnitude of power adjustment needed. This adaptive parameter selection provides sufficient precision for each situation while minimizing transmission overhead by using smaller corrections when possible.
Data Source
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AI summary
Systems and methodologies are described that facilitate employing aperiodic closed loop power control corrections in a Long Term Evolution (LTE) based wireless communication environment. An aperiodic power control command can be sent over a downlink to control and/or correct an uplink power level employed by an access terminal. Transmission of the aperiodic power control can be triggered by a measurement (e.g., received power being outside a set margin, ). The aperiodic power control command can include a single-bit and/or a multi-bit correction. Further, the access terminal can alter the uplink power level employed for subsequent uplink transmissions based upon the aperiodic power control command when received. Additionally, regardless whether the aperiodic power control command is received at a given time over the downlink, the access terminal can employ periodic power control commands and an open loop power control mechanism to adjust the uplink power level.