Distributed Tone Mapping for PSD-Limited Wireless Transmission
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Solution Overview
Problem
Wireless communication devices face reduced transmission ranges and packet detection capabilities due to power spectral density (PSD) limits, which restrict the allowable transmit power and affect channel estimation.
Innovation Solution
Implementing tone mapping techniques to distribute contiguous tones across a wider frequency bandwidth using a tone mapping vector and offset, allowing wireless communication devices to transmit data over non-contiguous tones, thereby increasing the effective transmit power without violating PSD limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If contiguous tones are used for transmission, then transmission simplicity is maintained, but transmission range and power gain are limited due to PSD constraints
Solution Approach 1:
The patent segments the frequency spectrum into multiple non-contiguous tone groups distributed across a wider bandwidth. Instead of using a single contiguous block of tones, the transmission tones are divided and scattered across multiple frequency segments, allowing the system to achieve higher effective transmit power while complying with PSD limits by spreading energy across a broader spectrum.
Solution Approach 2:
The patent transitions from a one-dimensional contiguous frequency allocation to a multi-dimensional distributed tone structure. By mapping tones across multiple frequency segments and utilizing tone mapping vectors and offsets, the system adds dimensional complexity to the frequency domain allocation, enabling higher power transmission while maintaining PSD compliance through broader spectral distribution.
2Object-affected harmful factors
If power spectral density limits are enforced, then interference to other channels is reduced, but transmission range and packet detection capability deteriorate
Solution Approach 1:
The patent segments the transmission spectrum into distributed non-contiguous tones across a wider bandwidth. This segmentation allows the system to maintain low PSD in any single frequency segment (reducing interference to other channels) while accumulating sufficient total transmit power across all segments to ensure reliable packet detection and extended transmission range.
Solution Approach 2:
The patent changes the frequency domain parameters by distributing tones across multiple frequency segments with specific spacing and offsets. This parameter transformation allows the system to comply with PSD limits in each segment while achieving higher effective transmit power through the aggregate of distributed tones, thereby maintaining packet detection capability and transmission range.
3Power
If contiguous tones are used, then channel estimation and packet detection are simpler, but transmission range is reduced
Solution Approach 1:
The patent segments the frequency spectrum into multiple non-contiguous tone groups and distributes them across a wider bandwidth. This segmentation enables the system to achieve higher effective transmit power while complying with PSD limits. The channel estimation process is adapted to handle the distributed tone structure by using tone mapping vectors and offsets to reconstruct the channel response across the original contiguous frequency allocation.
Data Source
AI summary
This disclosure provides systems, methods, and apparatuses for wireless communication. An example apparatus selects a first resource unit (RU) of a plurality of RUs for transmitting a physical (PHY) layer convergence protocol (PLCP) protocol data unit (PPDU) over a wireless medium. The first RU may include a set of contiguous tones occupying a first frequency bandwidth. The plurality of RUs may collectively span a second frequency bandwidth greater than the first frequency bandwidth. The apparatus maps the set of contiguous tones of the first RU to a set of non-contiguous tones distributed across the second frequency bandwidth using a tone mapping vector and a tone mapping offset associated with the first RU. The apparatus transmits the PPDU over the set of non-contiguous tones distributed across the second frequency bandwidth.