Reconfigurable Multimode Transceiver Sharing IFFT and Polyphase Filters

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Solution Overview

Problem

Conventional multimode transceivers require dedicated Application Specific Integrated Circuits (ASICs) for each Inverse Fast Fourier Transform (IFFT) and Inverse Wavelet Transform (IWT) mode, leading to high costs, bulkiness, and rigidity, making them difficult to upgrade or reconfigure, especially as wireless services shift from IFFT to IWT based systems.

Innovation Solution

A reconfigurable multimode multi-carrier transceiver design that uses shared resources, including variable-sized components and polyphase filters with real coefficients, to implement both IFFT and IWT modes, allowing for seamless switching between modes and upgrades through a controller and configuration means.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dedicated ASICs are used for each IFFT and IWT mode, then reliability and mode-specific performance are improved, but device complexity, cost, and size increase

Engineering Contradiction:

Improvemode-specific performanceVSAvoidtransceiver structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a universal transceiver architecture where a single IFFT block and a single IWT block share common resources including parallel-to-serial converters, modulators, and other processing components. This allows the same hardware infrastructure to support both IFFT-based OFDM and IWT-based DWMC modes, eliminating the need for separate dedicated ASICs for each mode while maintaining full functional capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges previously separate processing chains by combining the IFFT and IWT blocks to share common resources. Specifically, both transform blocks feed into shared parallel-to-serial converters, modulators, and transmission interfaces, creating an integrated architecture that reduces overall device complexity and component count while preserving mode-specific performance characteristics.

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If multiple dedicated ASICs are used for IFFT and IWT modes, then mode versatility is improved, but manufacturing cost increases

Engineering Contradiction:

Improvemultimode supportVSAvoidmanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent creates a universal processing platform where a single IFFT block and a single IWT block can handle both OFDM and DWMC modes through shared resources. This consolidation reduces the total number of ASICs required from multiple dedicated chips to a smaller set of multi-functional blocks, directly lowering manufacturing costs while maintaining full multimode versatility.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces dynamic configurability through a mode selector that can switch between IFFT and IWT processing paths based on the required communication standard. This dynamic switching capability allows the same hardware infrastructure to adapt to different modes (OFDM or DWMC) without requiring separate dedicated ASICs for each standard, reducing manufacturing complexity while preserving adaptability.

Inventive Principle:

Principle #15Dynamics

3Manufacturing precision

If fixed ASICs are used for each mode, then manufacturing precision is improved, but adaptability and upgradability deteriorate

Engineering Contradiction:

ImproveASIC design stabilityVSAvoidreconfiguration capability

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent transforms the static, fixed ASIC architecture into a dynamic, reconfigurable system through the introduction of a mode selector and shared resource architecture. The IFFT and IWT blocks can be dynamically activated or deactivated based on the selected mode (OFDM or DWMC), allowing the transceiver to be reconfigured for different standards and future upgrades without requiring new dedicated ASIC designs.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Device complexity

If variable-sized components and shared resources are used, then device complexity is reduced, but manufacturing precision requirements increase

Engineering Contradiction:

Improvetransceiver structureVSAvoidcomponent configuration

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS7898936B2Combined OFDM and wavelet multi-carrier transceiver

Publication Date: 2011.03.01 REDWOOD TECHNOLOGIES LLC

AI summary

A multicarrier transmitter and receiver uses a first inverse fast Fourier transformer for performing an Inverse Fast Fourier Transform (IFFT) on a parallel input data signal, an imaginary component filter for filtering out the imaginary component of an output signal of the first transformer and a real component filter for filtering out the real component of the output signal of the first. The multicarrier transmitter and receiver also uses a first polyphase filter having real coefficients. The first filter accepts output data from the imaginary component filter. The multicarrier transmitter and receiver also uses a second polyphase filter having real coefficients which are selected as the real coefficients of the first filter with the sign of each odd-numbered real coefficient inverted. The second filter accepts output data from said real component filter. A combined OFDM and wavelet multi-carrier transceiver is proposed sharing an IFFT block.