Downlink Power Allocation in Wireless Systems
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Solution Overview
Problem
Conventional downlink power allocation methods in OFDMA systems for wireless communication, such as IEEE 802.16d/e and WiMAX, result in inefficient data transmission and limited service coverage due to the need for terminals to report downlink quality information on uplink channels, leading to data loss and imbalance between transmission quantity and service area.
Innovation Solution
A method and apparatus for allocating downlink power in a radio access station system that calculates minimum requirement power and excess power based on downlink quality information, redistributing excess power from terminals with higher allocation power to those with lower power, ensuring all terminals receive the minimum required power for optimal communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If terminals report downlink quality information on uplink channels, then the radio access station can determine transmission power for each terminal, but data transmission efficiency decreases and service coverage is limited
Solution Approach 1:
The patent extracts the downlink quality information reporting function from the uplink data channel, allowing quality information to be transmitted separately without occupying uplink data resources. This resolves the contradiction by separating the measurement function from the data transmission function, improving both measurement precision and data transmission efficiency.
Solution Approach 2:
The patent implements a universal power allocation mechanism that serves multiple functions: determining transmission power for quality of service guarantees, optimizing overall system throughput, and expanding service coverage. This multi-functional approach resolves the contradiction by making the power allocation system adaptable to different operational requirements simultaneously.
2Productivity
If transmission power is allocated to maximize data transmission quantity, then transmission efficiency improves, but service area coverage is reduced
Solution Approach 1:
The patent implements dynamic power allocation that adjusts transmission power based on terminal conditions, channel quality, and service requirements. The system can dynamically switch between maximizing throughput for nearby terminals and expanding coverage for distant terminals, resolving the contradiction by making the power allocation flexible and context-dependent rather than fixed.
Solution Approach 2:
The patent applies different power allocation strategies to different terminals based on their specific conditions - terminals with good channel conditions receive power optimized for high throughput, while terminals at coverage edges receive power optimized for maintaining connection. This local optimization approach resolves the contradiction by treating different spatial regions and terminal types differently.
3Area of stationary object
If transmission power is allocated to maximize service coverage, then service area expands, but data transmission quantity decreases
Solution Approach 1:
The patent uses dynamic power allocation that can adapt between coverage-mode and throughput-mode operation. When coverage expansion is prioritized, power is distributed to maintain connections across larger areas; when throughput is prioritized, power is concentrated on active data transmissions. This dynamic switching resolves the contradiction by allowing the system to optimize for different goals based on current needs.
4Measurement precision
If downlink quality information is reported for each channel at every frame, then channel quality measurement is comprehensive, but uplink data transmission capacity is reduced
Solution Approach 1:
The patent extracts quality information reporting from the uplink data channel and transmits it through a dedicated feedback mechanism. This separation ensures that quality measurement comprehensiveness does not consume uplink data capacity, resolving the contradiction by giving quality reporting its own transmission path independent of data channels.
Data Source
AI summary
A method and apparatus of allocating downlink power in a radio access station system are disclosed. The method of allocating transmission power to a plurality of terminals in a radio access station system according to the present invention includes (A-1) calculating an allocation power for the respective terminals based on downlink quality information of the respective terminals; (A-2) calculating a minimum requirement power for the respective terminals based on the downlink quality information; and (A-3) allocating the transmission power by distributing part of excess power of a first terminal group having the allocation power higher than the minimum requirement power to the second terminal group having the allocation power lower than the minimum requirement power, and the part of excess power is a sum of insufficient power of the second terminal group. As a result, the loss of the quantity of service transmission of the radio access station is reduced and service areas can be expanded.