PPDU Modulation Duplication for PSD-Limited Wireless Transmission
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Solution Overview
Problem
Conventional PPDU designs and encoding techniques do not account for punctured subchannels, leading to restricted transmission range and data rate inefficiencies in wireless communications.
Innovation Solution
A PPDU is generated with a base modulation frequency unit duplicated to unpunctured subchannels and phase-rotated, ensuring compliance with power spectrum density limits, particularly for non-orthogonal frequency-division multiple access transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional PPDU designs and encoding techniques are used, then device complexity is reduced, but transmission range and data rate are restricted
Solution Approach 1:
The patent segments the frequency spectrum into punctured and unpunctured subchannels, allowing independent handling of each segment. The base modulation frequency unit is identified and separately processed, then duplicated to unpunctured subchannels with phase rotation. This segmentation enables the system to adapt to PSD limits by selectively using available frequency resources without redesigning the entire PPDU structure.
Solution Approach 2:
The patent changes key parameters including applying phase rotation to duplicated base modulation frequency units, adjusting modulation schemes (e.g., DCM, TCM), and modifying resource unit allocations. These parameter changes enable compliance with PSD limits while maintaining or improving transmission range and data rate without fundamental structural changes to the PPDU design.
2Productivity
If base modulation frequency unit is duplicated to unpunctured subchannels with phase rotation, then transmission efficiency and range are enhanced, but device complexity increases
Solution Approach 1:
The patent performs preliminary identification of the base modulation frequency unit before duplication. By pre-processing the modulation unit and determining its characteristics, the system prepares the data structure in advance for efficient duplication and phase rotation operations. This preliminary action reduces the computational burden during actual transmission and simplifies the encoding process.
Solution Approach 2:
The patent creates copies of the base modulation frequency unit and places them in unpunctured subchannels with applied phase rotation. This copying approach allows the system to leverage the same modulated data across multiple frequency resources, improving transmission efficiency and robustness without requiring entirely new modulation schemes for each subchannel.
3Use of energy by moving object
If PSD limit compliance is enforced, then spectral efficiency improves, but transmission data rate is restricted
Solution Approach 1:
The patent transitions from a single-dimension approach (single frequency channel) to a multi-dimensional approach by duplicating the base modulation frequency unit across multiple unpunctured subchannels with different phase rotations. This dimensional expansion in the frequency domain allows the system to maintain spectral efficiency within PSD limits while achieving higher effective data rates through spatial diversity and parallel transmission paths.
Solution Approach 2:
The patent merges multiple unpunctured subchannels into a unified transmission structure by duplicating and phase-rotating the base modulation frequency unit across them. This merging approach combines the spectral efficiency benefits of PSD limit compliance with the data rate advantages of multi-subchannel transmission, achieving both goals simultaneously through coordinated resource allocation.
Data Source
AI summary
A device, a system, and a method for power spectrum density (PSD) limited transmissions are disclosed. In an embodiment, the device includes a wireless network interface device implemented on one or more integrated circuits (ICs), where the wireless network interface device is configured to generate a Physical Layer Convergence Procedure (PLCP) Protocol Data Unit (PPDU) that includes a base modulation frequency unit, where the base modulation frequency unit is duplicated to unpunctured subchannels of the PPDU with a phase rotation, and transmit the PPDU in accordance with a power spectrum density (PSD) limit.