Beam-Specific Power Control for Massive MIMO Uplink Accuracy
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Solution Overview
Problem
In massive MIMO wireless communication systems, existing power headroom reporting mechanisms are inadequate for accurate uplink power adjustment due to differences in long-time channel fading between signals using different beamforming vectors, leading to inaccuracy and performance loss.
Innovation Solution
A method that involves transmitting multiple difference values for power headroom reporting through higher layer signaling, allowing for beam-specific power control by determining reference powers for each antenna port group, which corresponds to specific beamforming vectors, thereby enabling more accurate uplink power adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single uplink power control process is used for all antenna ports, then the device complexity is reduced, but the power adjustment accuracy deteriorates due to differences in long-time channel fading between different beamforming vectors
Solution Approach 1:
The patent divides the uplink power control process into multiple independent processes, each associated with a specific antenna port group and beamforming vector. This segmentation allows each process to independently adjust power based on channel characteristics of its corresponding beam, resolving the contradiction by trading controlled complexity for significantly improved power adjustment accuracy.
Solution Approach 2:
The patent implements beam-specific power control where each antenna port group has its own power control parameters and processes tailored to local channel conditions. This local quality approach ensures that power adjustments are optimized for each specific beamforming vector's channel characteristics, improving overall system performance despite increased complexity.
2Loss of information
If multiple difference values are reported through multiple reporting instances, then the power headroom information completeness is improved, but the time delay increases
Solution Approach 1:
The patent combines multiple power headroom difference values into a single reporting instance, where the MAC CE message carries multiple difference values simultaneously. This merging approach maintains complete power headroom information for multiple antenna port groups while reducing the time delay associated with multiple sequential reporting instances.
Data Source
AI summary
The disclosure provides a method and a device in a User Equipment (UE) and a base station for power adjustment. In one embodiment, the UE transmits a first radio signal in a first time window, wherein the first radio signal is used for determining K difference value(s), the K difference value(s) is (are one-to-one) corresponding to K reference power(s), and the reference power is a power estimated for transmission of an uplink channel. Measurement(s) for K antenna port group(s) are used for determining the K reference power(s respectively), the first radio signal is used for determining position(s) of the K antenna port group(s) in L antenna port groups, the antenna port group comprises a positive integer number of antenna ports. The disclosure can support multiple independent closed-loop power control processes for one serving cell or carrier, thereby improving efficiency and performance of uplink power control.