Mobile Station Bandwidth Detection Using Dynamic FFT and Guard Subcarriers
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Solution Overview
Problem
Broadband wireless communication systems face challenges in supporting various system bandwidths due to the rarity of frequency bands and the variability of required bandwidths across different countries and service providers, without increasing system complexity or reducing transmission efficiency.
Innovation Solution
The solution involves determining the system bandwidth through a primary preamble for frame synchronization, using a Fast Fourier Transform (FFT) size, number of guard subcarriers, and number of used subcarriers, with operation parameters set accordingly to support multiple bandwidths, and optimizing frequency partition rates using predefined tables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If predefining various system bandwidths is implemented to meet different bandwidth requirements, then adaptability to different service provider needs is improved, but system complexity increases due to the uncertainty and variety of required bandwidths
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the number of guard subcarriers and frequency partition rates based on the detected system bandwidth. Instead of defining multiple fixed bandwidth configurations, the system changes key parameters (guard subcarrier count, frequency partition rate) according to the actual bandwidth requirement, allowing flexible adaptation while maintaining a unified system structure.
Solution Approach 2:
The patent implements dynamics by making the guard subcarrier configuration and frequency partition rate adjustable rather than fixed. The Mobile Station detects the system bandwidth and dynamically determines the appropriate number of guard subcarriers and frequency partition rate, enabling the system to adapt to varying bandwidth requirements without predefining multiple static configurations.
2Adaptability or versatility
If the number of guard subcarriers is increased to accommodate larger system bandwidths, then bandwidth coverage is improved, but system transmission efficiency deteriorates due to more subcarriers being wasted as guards
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the number of guard subcarriers based on the detected system bandwidth. For smaller bandwidths, fewer guard subcarriers are used; for larger bandwidths, more guard subcarriers are allocated. This dynamic parameter adjustment ensures adequate bandwidth coverage while minimizing the number of wasted guard subcarriers in each specific scenario.
Solution Approach 2:
The patent applies local quality by optimizing the guard subcarrier configuration for each specific bandwidth scenario. Rather than using a uniform guard subcarrier count for all bandwidth sizes, the system tailors the number of guard subcarriers to match the actual bandwidth requirement, ensuring that each local configuration (bandwidth size) has the appropriate quality (guard subcarrier count) to maintain both coverage and efficiency.
3Device complexity
If a fixed FFT size is used to simplify system configuration, then device complexity is reduced, but the ability to support various system bandwidths is limited
Solution Approach 1:
The patent applies parameter changes by making the FFT size adjustable based on the detected system bandwidth. The Mobile Station detects the bandwidth and determines the appropriate FFT size, allowing the system to support various bandwidths with different FFT sizes (e.g., 1K, 2K, 3K, 4K) while maintaining a relatively simple configuration process through automatic detection and determination.
Data Source
AI summary
An apparatus and method support various system bandwidths in a broadband wireless communication system. A Mobile Station (MS) operation includes determining a system bandwidth through a primary preamble for frame synchronization, which a Base Station (BS) transmits. A Fast Fourier Transform (FFT) size, the number of guard subcarriers, and the number of used subcarriers corresponding to the system bandwidth are determined using a first table. An operation parameter of a modem is set according to the FFT size, the number of guard subcarriers, and the number of used subcarriers.