Radio Parameter Sets for OFDM Guard Interval Adaptation
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Solution Overview
Problem
In OFDM-based mobile communication systems, it is challenging to determine a single optimized guard interval period that balances communication quality across various environments, such as urban and indoor areas, for both unicast and multicast schemes, due to varying propagation delays and signal processing constraints in mobile stations with limited resources.
Innovation Solution
A transmitter and receiver system that generates sets of radio parameters with adjustable guard interval periods and subcarrier intervals, allowing for flexible operation between unicast and multicast schemes, while maintaining constant data transmission efficiency by keeping the occupancy proportion of the guard interval constant, and allowing for selection of optimal radio parameters based on communication conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a larger guard interval period is used, then fading tolerance and inter-symbol interference reduction are improved, but information transmission efficiency deteriorates
Solution Approach 1:
The patent implements dynamic guard interval period selection by providing multiple sets of radio parameters with different guard interval periods (e.g., 1/4, 1/8, 1/16, 1/32 of effective symbol period). The mobile station selects the appropriate set based on communication conditions such as propagation delay and fading characteristics, allowing the system to adapt between long guard intervals for fading tolerance and short guard intervals for transmission efficiency.
2Adaptability or versatility
If multiple sets of radio parameters with various symbol formats are provided, then adaptability to different communication environments is improved, but signal processing workload and device complexity deteriorate
Solution Approach 1:
The patent changes key parameters (guard interval period, subcarrier interval, cyclic shift length) across different radio parameter sets while maintaining the fundamental OFDM signal processing architecture. This allows the mobile station to adapt to different environments by selecting appropriate parameter sets without requiring fundamentally different processing schemes, thus balancing adaptability with manageable complexity.
Solution Approach 2:
The patent designs the radio parameter sets to maintain compatibility with a universal signal processing framework. All sets use the same basic OFDM modulation and demodulation processes, with only specific parameters varying. This universal approach allows a single mobile station design to handle multiple communication scenarios without requiring multiple specialized processing paths.
3Productivity
If a relatively short guard interval part is used, then information transmission efficiency is improved, but fading tolerance and inter-symbol interference reduction deteriorate
Solution Approach 1:
The system dynamically selects between short and long guard interval configurations based on real-time communication conditions. In environments with short propagation delays (urban areas, indoor), short guard intervals are selected for high transmission efficiency. In environments requiring longer delay spread coverage (large cell radius, multicast scenarios), long guard intervals are selected to maintain fading tolerance and reduce inter-symbol interference.
Data Source
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AI summary
An apparatus for generating sets of radio parameters includes a first deriving unit deriving a set of radio parameters for specifying a symbol including an effective symbol part with the same period as the effective symbol part specified by another set of radio parameters and a guard interval part with a different period from the guard interval part specified by the other set of radio parameters. The apparatus further includes a second deriving unit deriving a set of radio parameters so that an occupancy proportion of the guard interval part in a single symbol specified by another set of radio parameters is equal to an occupancy proportion of the guard interval part in a single symbol specified by the other set of radio parameters.