Radio Transmission Device Subcarrier Allocation for PAPR Reduction
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Solution Overview
Problem
Conventional layered modulation methods for radio communication systems using high carrier frequencies face challenges in maintaining cell coverage and error rate characteristics, leading to increased installation costs due to high Peak to Average Power Ratio (PAPR) and reduced transmission power efficiency.
Innovation Solution
A radio transmitting apparatus employing a configuration with a first subcarrier modulation section, a second subcarrier modulation section, and a subcarrier mapping section to control allocation of subcarrier modulation signals, reducing PAPR and enhancing transmission power efficiency, while allowing flexible frequency resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional layered modulation method is used, then error rate characteristic is maintained, but PAPR increases and transmission power efficiency decreases
Solution Approach 1:
The invention divides the subcarrier modulation signals into two distinct types: first subcarrier modulation signals generated by converting modulation signals to the frequency domain, and second subcarrier modulation signals generated by parallel conversion. This segmentation allows different signals to be allocated to different subcarriers, enabling PAPR reduction while maintaining error rate characteristics through selective allocation strategies.
Solution Approach 2:
The invention applies different modulation and allocation strategies to different subcarrier groups. First subcarrier modulation signals are allocated to certain subcarriers while second subcarrier modulation signals are allocated to other subcarriers, allowing localized optimization of signal characteristics to reduce PAPR in specific frequency regions while maintaining overall transmission reliability.
2Productivity
If high carrier frequency band is used, then transmission rate is improved, but cell coverage decreases
Solution Approach 1:
The invention dynamically allocates first and second subcarrier modulation signals to different subcarriers based on channel conditions and transmission requirements. This dynamic allocation enables the system to optimize both transmission rate and cell coverage by adaptively distributing spectral resources, allowing high carrier frequency operations to maintain extended cell coverage through intelligent signal placement.
3Area of stationary object
If multiple base stations are installed to increase cell coverage, then coverage area is expanded, but installation cost increases
Solution Approach 1:
The invention changes the parameters of subcarrier modulation signal allocation by introducing two distinct modulation signal generation methods with different characteristics. By optimizing the allocation of these signals across subcarriers, the system achieves enhanced cell coverage with a single base station, eliminating the need for multiple base stations and reducing installation costs while maintaining expanded coverage area.
Data Source
AI summary
Provided is a radio transmission device (100) which can flexibly cope with a request for assuring an error ratio feature during a high transmission rate, a request for increasing a cell coverage, or the like. The radio transmission device (100) includes a first subcarrier modulation unit (104) which forms a first subcarrier modulation signal obtained by converting a plurality of modulation signals into a frequency region; a second subcarrier modulation unit (105) which forms a second subcarrier modulation signal obtained by parallel conversion of a plurality of signals; an IFFT unit (111) which forms an OFDM signal by performing inverse Fourier transform on the first and the second subcarrier modulation signal; and a subcarrier mapping unit (110) which controls allocation of the first and the second subcarrier modulation signals.