MIMO Stream Power Control for Estimation Error Sensitivity
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Solution Overview
Problem
In wireless communication systems using MIMO techniques, poor accuracy in transmission power estimation leads to deteriorated reception characteristics and decreased channel use efficiency, especially when M-ary modulation symbols are controlled.
Innovation Solution
A transmitting apparatus that adjusts power control values for streams, prioritizing the stream most sensitive to power estimation errors and applying a reference value, while distributing adjustment values to other streams to maintain optimal channel capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transmission power is controlled for M-ary modulation symbols to maximize channel capacity, then channel use efficiency is improved, but reception characteristics deteriorate when power estimation accuracy is poor
Solution Approach 1:
The patent applies parameter changes by adjusting the power control values dynamically based on the sensitivity of each stream to power estimation errors. Different power control parameters are assigned to different streams depending on their modulation schemes and coding rates, allowing the system to optimize channel capacity while maintaining reception reliability through adaptive parameter adjustment.
Solution Approach 2:
The patent implements local quality by treating each stream differently based on its specific characteristics (modulation scheme, coding rate, and sensitivity to power estimation errors). Instead of applying a uniform power control approach, the system assigns tailored power control values to each stream, ensuring that streams more sensitive to power errors receive adjusted power levels that prioritize reception reliability.
2Ease of operation
If common pilot is transmitted at constant power for link adaptation, then channel monitoring is simplified, but channel use efficiency decreases when power distribution is not optimized
Solution Approach 1:
The patent applies segmentation by separating the power control into two distinct parts: the common pilot signal maintains constant power for simplified channel monitoring and estimation, while the data-bearing streams receive differentiated power control values optimized for their specific characteristics. This segmentation allows the system to maintain operational simplicity for monitoring while achieving enhanced efficiency for data transmission.
Solution Approach 2:
The patent implements local quality by applying different power control strategies to different signal components. The common pilot continues with uniform power distribution for ease of processing, while individual data streams receive tailored power control based on their sensitivity to power estimation errors and their contribution to channel capacity.
3Reliability
If power control values are adjusted for streams sensitive to power estimation errors, then reception reliability is improved, but device complexity increases
Solution Approach 1:
The patent applies feedback by utilizing the power control values reported from the receiving side through feedback signals. The transmitting side adjusts power control values based on this feedback information, creating a closed-loop system that automatically adapts to channel conditions and optimizes both reliability and efficiency without requiring overly complex processing.
Solution Approach 2:
The patent implements partial action by applying power control adjustments only to the subset of streams that are most sensitive to power estimation errors, rather than uniformly adjusting all streams. This selective approach improves reception reliability for critical streams while minimizing the overall processing complexity required for power control.
Data Source
AI summary
A transmitting apparatus, a receiving apparatus and a transmission power control method wherein even in a case of performing a transmission power control of multi-valued modulated symbols, the degradation of reception characteristic and that of network usage efficiency can be avoided. A power control instructing part (204) adjusts, based on an encoding rate and a modulation scheme in a case of applying a power control value, which maximizes the MIMO channel capacity, to each stream, the power control value of a stream, which is the most likely to be affected by a power estimation error, into a reference value, and then applies the adjustment value used for that adjustment to the other streams, that is, the streams that are not likely to be affected by the power estimation error. A power control part (205) performs a transmission power control in accordance with the power control value as adjusted by the power control instructing part (204).