TFC Selection Unit for HSUPA Power Amplifier Distortion Control
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Solution Overview
Problem
The increasing number of channels code-multiplexed in 3GPP Release 6 HSUPA systems leads to a high Peak to Average power Ratio (PAR), causing distortion in Power Amplifiers and degrading Adjacent Channel Leakage power Ratio (ACLR, and existing methods for determining maximum transmission power reduction become impractical due to the large number of β-combinations, resulting in inefficient TFC selection.
Innovation Solution
A communication terminal device and method that groups gain factors into classifications, storing corresponding reduction values in a storage unit to facilitate efficient TFC selection by reading and applying these values during the selection process, allowing for optimized TFC selection and reduced PAR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the number of transmission channels code-multiplexed is increased to achieve high-speed data communication, then the data transmission rate is improved, but the PAR is increased causing distortion in PA and degradation of ACLR
Solution Approach 1:
The patent changes the parameter representation from individual β values to classification groups. By categorizing β values into discrete classification groups and pre-calculating MPR for each group combination, the system manages the complexity of multiple multiplexed channels while controlling PAR through classified parameter selection rather than continuous parameter adjustment.
Solution Approach 2:
The patent performs preliminary classification of β values into groups and pre-calculates the MPR values for all possible classification combinations before actual TFC selection. This preliminary action creates a lookup table that enables fast TFC selection without real-time complex calculations, allowing high-speed data transmission while pre-managing the PAR distortion issue.
2Adaptability or versatility
If the number of β-combinations is increased to support more channels code-multiplexed, then the channel multiplexing capability is improved, but the complexity of determining MPR using look-up tables increases making simple case classification difficult
Solution Approach 1:
The patent segments the continuous β value space into discrete classification groups. Instead of handling individual β values or all possible β-combinations directly, the system divides β values into a limited number of classification groups (e.g., Group 0, Group 1, etc.), thereby reducing the complexity of MPR determination while maintaining support for multiple code-multiplexed channels.
Solution Approach 2:
The patent performs preliminary classification of β values into groups and pre-calculates the MPR values for all possible classification combinations before actual TFC selection. This creates a manageable lookup table structure where the complexity is handled in advance, enabling simple case classification during runtime even with many β-combinations.
3Measurement precision
If MPR is calculated by sampling transmission waveform downstream of FIR filter to obtain accurate CM value, then the measurement precision is improved, but the processing load increases and circuit complexity increases
Solution Approach 1:
The patent performs the complex CM calculation and MPR determination in advance during system initialization or configuration phase. By pre-calculating MPR values for all classification group combinations and storing them in a lookup table, the actual transmission process only requires simple table lookup based on current β-classifications, thereby maintaining measurement precision while dramatically reducing real-time processing load and circuit complexity.
Solution Approach 2:
The patent creates a copy of the MPR values in a lookup table structure organized by classification group combinations. Instead of performing complex waveform sampling and CM calculation during each TFC selection, the system uses a pre-generated copy of MPR data that can be quickly accessed, reducing circuit complexity while maintaining accuracy.
Data Source
AI summary
A communication terminal device is operable to multiplex a plurality of channel signals based on TFC (Transport Format Combination) selected by performing a TFC selection and transmit it. The communication terminal device includes a storage unit operable to store a plurality of combination of classifications to which the gain factors belong, as a combination of gain factors for weighting each of the plurality of channel signals, and to store a quantity of reduction of a maximum transmission power when the plurality of channel signals in association with each combination of the plurality of classifications are multiplexed and transmitted, and a TFC selection unit operable to select the TFC by reading out the quantity of reduction in association with the combination of the classification corresponding to the combination of the gain factors in each TFC from the storage unit when the TFC selection is performed.