DCM and Distributed Tone RU Mapping for PPDU Range Extension
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Solution Overview
Problem
The use of distributed tone resource units (dRU) in wireless communication systems, while enhancing transmission range, is limited by power spectral density constraints, particularly in low-power indoor modes, leading to a bottleneck in transmission range extension.
Innovation Solution
Combining dual carrier modulation (DCM) with dRU to boost transmission power and diversity gains, specifically by repeating and boosting certain PPDU preamble fields, such as the U-SIG and UHR-LTF fields, to balance the transmission range of the PPDU preamble and data field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If distributed tone resource units (dRU) are used to increase transmission power, then transmission range is extended, but power spectral density constraints limit the maximum transmission power boost
Solution Approach 1:
The patent combines dual carrier modulation (DCM) with distributed tone resource units (dRU) to merge two techniques for achieving greater transmission range extension. DCM provides power boosting by modulating two carriers simultaneously, while dRU distributes tones across the spectrum to enable higher transmission power, creating a synergistic effect that overcomes individual limitations.
Solution Approach 2:
The patent introduces a new dimension to the transmission system by applying DCM across multiple dRUs, transforming the single-carrier single-RU approach into a multi-carrier multi-RU system. This dimensional expansion allows simultaneous exploitation of frequency diversity and power boosting effects.
2Length of moving object
If dRU is used to boost transmission power, then transmission range increases, but the transmission range of PPDU preamble and data field becomes unbalanced
Solution Approach 1:
The patent applies different transmission strategies to different parts of the PPDU structure. Specifically, it applies DCM with power boosting selectively to the data field while using conventional transmission for the preamble, or applies different levels of DCM repetition to balance the effective range of preamble and data field components.
Solution Approach 2:
The patent changes transmission parameters (power level, modulation scheme, repetition factor) differently for preamble and data field portions of the PPDU. By adjusting these parameters independently, the system balances the effective transmission ranges of different PPDU components, ensuring both are reliably received.
3Reliability
If DCM with dRU is applied to extend transmission range, then reception reliability improves, but device complexity increases
Solution Approach 1:
The patent segments the transmission into multiple dRUs, each carrying a portion of the modulated signal. This segmentation allows independent processing and optimization of each resource unit, managing complexity through modular structure while achieving diversity gains across the distributed tones.
Data Source
AI summary
A method performed by a wireless device to extend an effective transmission range of a physical layer protocol data unit (PPDU). The method includes transmitting a PPDU that includes a preamble and a data field, wherein the data field is transmitted in a plurality of distributed-tone resource units (dRUs) each carrying a same set of data symbols. A different mapping of the same set of data symbols to tone positions may be used in different ones of the plurality of dRUs to increase frequency diversity.