OFDM Downlink Power Allocation Using Channel Variance
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Solution Overview
Problem
Current OFDM communication systems lack an effective method to allocate downlink power based on both mean Signal to Noise Ratio (SINR) and its second order statistics, which is inadequate for accurately describing channel conditions, especially in frequency selective fading channels.
Innovation Solution
A method and apparatus that allocate downlink power in an OFDM communication system using both a mean channel quality metric and a channel quality metric second order statistic, such as variance or standard deviation, reported by mobile stations, to optimize power allocation for downlink transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If only mean SINR is reported for channel quality feedback, then feedback overhead is reduced, but channel condition description accuracy deteriorates especially in frequency selective fading channels
Solution Approach 1:
The patent transforms the channel quality feedback from a single parameter (mean SINR) to multiple parameters by introducing second order statistics (variance or standard deviation) alongside the mean SINR. This parameter expansion enables more accurate channel condition description, particularly for frequency selective fading channels, while maintaining manageable feedback overhead through efficient reporting mechanisms.
2Manufacturing precision
If downlink power allocation uses only mean SINR, then power allocation complexity is reduced, but power allocation accuracy and bandwidth utilization deteriorate
Solution Approach 1:
The power allocation algorithm incorporates both mean SINR and its second order statistics (variance/standard deviation) as input parameters. This dual-parameter approach enables more accurate determination of required transmit power by capturing both the average channel quality and its variability, leading to improved bandwidth utilization and signal quality while maintaining computational feasibility.
Data Source
AI summary
In an Orthogonal Frequency Division Multiplexing communication system, a radio access network allocates a transmit power for a downlink transmission to a mobile station based on a mean channel quality metric and a channel quality metric second order statistic, in various embodiments a channel quality metric variance or standard deviation, reported by the mobile station.