OFDM Symbol Assembly Circuit for Non-Standard Guard Intervals
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Solution Overview
Problem
Current Multi-band Orthogonal Frequency Division Multiplex (MB-OFDM) systems face challenges in generating orthogonal frequency division multiplex symbols of specific lengths, particularly for ultra-wideband wireless communications, where existing methods struggle to efficiently assemble symbols with non-standard sample lengths, impacting data transmission rates and network performance.
Innovation Solution
A circuit and method are introduced to assemble an orthogonal frequency division multiplex symbol by using a combination of multiplexers and memory cells to select and route samples based on a clock signal, allowing for the construction of a 165 sample length symbol comprising data, cyclic prefix, and guard samples, facilitating reliable communication and time-frequency interleaving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing MB-OFDM methods are used to generate symbols, then standard symbol lengths can be produced, but non-standard sample lengths (e.g., 165 samples) cannot be efficiently assembled
Solution Approach 1:
The symbol assembly process is segmented into distinct functional blocks: a first multiplexer selects between data samples and cyclic prefix samples, while a second multiplexer selects between the assembled symbol and guard samples. This segmentation allows independent control of different symbol components, enabling flexible assembly of non-standard lengths without compromising transmission efficiency.
Solution Approach 2:
The system dynamically adjusts sample routing based on the desired symbol length. The multiplexers are controlled to selectively connect different input sources (data samples, cyclic prefix, guard samples) depending on the required output length, allowing the symbol generator to adapt to various transmission requirements while maintaining high productivity.
2Adaptability or versatility
If a fixed symbol assembly method is used, then simple circuit design is achieved, but flexible symbol length configuration is not possible
Solution Approach 1:
The multiplexer-based architecture provides universal functionality for assembling symbols of any length. The same circuit structure (two multiplexers with controlled switching) can generate both standard and non-standard symbol lengths by simply changing the control signals, eliminating the need for multiple dedicated circuits for different symbol types.
Solution Approach 2:
The multiplexers act as intermediary components between the fixed-length sample inputs and the variable-length symbol output. By introducing these switching intermediaries, the system bridges the gap between fixed circuit architecture and flexible symbol length requirements, managing complexity through controlled signal routing rather than complex reconfigurable logic.
3Productivity
If standard MB-OFDM symbol generation is used, then processing efficiency is maintained, but non-standard sample lengths (165 samples) cannot be generated
Solution Approach 1:
The cyclic prefix samples are prepared in advance and stored in a dedicated buffer, ready for rapid insertion into the symbol stream. This preliminary preparation of guard and prefix samples allows the multiplexers to quickly assemble non-standard symbol lengths without compromising processing efficiency, as the samples are pre-processed and immediately available for routing.
Data Source
AI summary
A sequence of data samples and a sequence of non-data samples are provided. Four input samples from one of the data samples and the non-data samples are selected based on a clock signal. At least a portion of contents of a first group of memory cells are stored in a second group of memory cells. The first group of memory cells are comprised of four memory cells. The selected four input samples are stored in the first group of memory cells.