Dynamic Header Field Size Selection for OFDM Interference
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Solution Overview
Problem
Existing multi-carrier modulation techniques, such as OFDM, face challenges in optimizing the size of the cyclic prefix (header field) for transmission channels, leading to suboptimal bit rate and quality due to empirical approaches that may result in either too short or too long header fields, impacting throughput and transmission quality.
Innovation Solution
A method that iteratively selects the optimal size of the header field based on the power spectral density of noise due to interference, maximizing the bit rate while keeping noise below a threshold, using a composite performance criterion that accounts for both bit rate and interference noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the size of the header field is increased, then the noise due to interference is reduced, but the bit rate of the transmission channel decreases
Solution Approach 1:
The patent implements dynamic adaptation of the header field size based on channel conditions. The system determines the dispersion of delays from the impulse response and calculates an optimal header field size that varies with channel characteristics, transitioning from static predetermined sizes to dynamic optimization. This resolves the contradiction by making the header field size adaptable rather than fixed, allowing the system to achieve noise reduction only when necessary while maintaining higher bit rates when channel conditions permit.
Solution Approach 2:
The patent changes the parameter of header field size from a fixed predetermined value to a dynamically determined value based on channel impulse response analysis. By calculating the dispersion of delays and deriving an optimal header field size from channel characteristics, the system transforms the header field size parameter to optimize both noise reduction and bit rate performance according to actual transmission conditions.
2Productivity
If the size of the header field is decreased, then the bit rate is maintained, but the noise due to interference is not sufficiently corrected
Solution Approach 1:
The system dynamically adjusts the header field size based on measured channel conditions rather than using a fixed small size. By determining the dispersion of delays from the impulse response and calculating the optimal header field size accordingly, the system ensures sufficient noise correction is applied only when channel conditions require it, rather than always using a conservative small header field size that would fail to correct interference.
Solution Approach 2:
The patent incorporates feedback mechanisms where the system determines the impulse response of the transmission channel, calculates the dispersion of delays, and uses this information to adaptively select the header field size. This feedback loop ensures that the header field size is optimized based on actual channel conditions, preventing both insufficient noise correction and excessive bit rate reduction.
3Ease of manufacture
If an empirical rule is used to determine header field size, then the implementation is simple, but the optimization of bit rate and quality is insufficient
Solution Approach 1:
The patent replaces empirical rule-based determination with a calculation-based approach using channel impulse response analysis. Instead of relying on simple empirical formulas, the system determines the dispersion of delays from measured impulse response data and calculates the optimal header field size mathematically. This substitution of calculation methods achieves better optimization while maintaining reasonable implementation complexity through standardized signal processing techniques.
Solution Approach 2:
The system performs self-optimization by automatically determining its own optimal header field size based on measured channel conditions. The receiver determines the impulse response, calculates dispersion of delays, and derives the optimal header field size without requiring external configuration or complex iterative optimization processes, enabling the system to self-adjust to channel conditions efficiently.
Data Source
Figure 1~5
AI summary
The method involves choosing a size of a header field from a set of distinct predetermined sizes of header fields. Power spectral density of noise due to interferences between data blocks and interferences between carriers present in a transmission channel (C) is determined for the chosen size based on an impulse response of the channel. Performance criterion of the channel is obtained based on the power spectral density. A size of header field is selected from the set of sizes of header fields based on a value of the performance criterion of the channel associated to the size of header field. Independent claims are also included for the following: (1) a device for determining the size of a header field in a data block (2) a computer program comprising a set of instructions for implementing a method for determining the size of a header field in a data block (3) a recording medium comprising a set of instructions for implementing a method for determining the size of a header field in a data block.