Sub-Band Error Correction Coding for OFDMA Power Allocation
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Solution Overview
Problem
Beyond 4G (B4G) radio systems face challenges in maintaining high spectrum efficiency due to the dependence of Orthogonal Frequency Division Multiple Access (OFDMA) on coding rates, which leads to poor performance under weak subcarriers and interference, necessitating adaptive modulation and power control but lacking clear methods for joint control.
Innovation Solution
A method involving determining relative radio channel qualities and allocating transmission power between sub-bands based on these qualities and the coding rate to optimize spectral efficiency and link adaptation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a high coding rate is employed to increase spectral efficiency, then the proportion of net information per gross information increases, but OFDMA performance deteriorates because coding cannot compensate for weak subcarriers and deep fades
Solution Approach 1:
The patent applies local quality by allocating different transmission powers to different sub-bands based on their individual channel qualities. Instead of using a uniform coding rate and power across all subcarriers, the system adapts the coding rate and power allocation locally to each sub-band's channel conditions, allowing high coding rates to be used only where channel quality permits while maintaining reliability in poor conditions.
Solution Approach 2:
The patent implements dynamics by making the coding rate and power allocation adaptive rather than static. The base station determines the coding rate based on uplink channel quality feedback from the UE and dynamically adjusts power allocation across sub-bands according to varying channel conditions, enabling the system to optimize spectral efficiency while maintaining performance under changing radio conditions.
2Reliability
If the MCS is selected according to the worst sub-carries to maintain OFDMA performance, then reliability is preserved, but spectral efficiency cannot be maintained at high levels
Solution Approach 1:
The patent resolves this contradiction by applying local quality through frequency-selective power allocation. Instead of uniformly selecting MCS based on the worst sub-carriers across the entire bandwidth, the system identifies sub-bands with good channel qualities and allocates higher power to those specific sub-bands, allowing higher MCS and coding rates to be used locally where appropriate, thereby maintaining both reliability and spectral efficiency.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the coding rate and power allocation parameters based on measured channel qualities of different sub-bands. The base station receives channel quality feedback, determines appropriate coding rates for different sub-bands, and adjusts power allocation accordingly, enabling the system to achieve high spectral efficiency while maintaining performance through adaptive parameter optimization.
3Quantity of substance
If wide frequency bandwidth is allocated to a single UE to increase resource allocation, then more data can be transmitted, but the channel is likely to fade within the allocated resources requiring higher coding rates
Solution Approach 1:
The patent applies segmentation by dividing the wide frequency bandwidth into multiple sub-bands and allocating different coding rates and power levels to each sub-band based on their individual channel qualities. This segmentation allows the system to transmit large quantities of data across wide bandwidth while maintaining reliability by using appropriate coding rates for each sub-band's channel conditions, avoiding the need to use conservative coding rates across the entire bandwidth.
Solution Approach 2:
The patent resolves the contradiction between wide bandwidth allocation and channel stability by applying local quality through sub-band specific power allocation and coding rate selection. Each sub-band is evaluated independently and allocated resources according to its local channel quality, enabling wide bandwidth utilization while maintaining reliability in fading conditions through localized adaptation.
Data Source
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AI summary
Improved adaptation to a frequency band comprising sub-bands is provided by receiving a coding rate of an error correction coding scheme for encoding modulation symbols to be transmitted on sub-bands of a frequency band in radio communications, determining relative radio channel qualities of the sub-bands of the frequency band, and allocating transmission power between the sub-bands at least on the basis of the relative radio channel qualities of the sub-bands and the received coding rate.