OTFS Modulation With Delay-Doppler Mapping for Low-Overhead Wireless Links
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Solution Overview
Problem
Current wireless communication networks face challenges in accommodating the rapid growth in data traffic and providing high-quality service due to bandwidth limitations, necessitating the development of next-generation wireless technologies that can efficiently manage increasing data demands.
Innovation Solution
The implementation of orthogonal time frequency space (OTFS) modulation, which maps digital data to a digital amplitude modulation constellation in the delay-Doppler domain and uses a steerable directional antenna, allows for efficient resource allocation and transmission in a two-dimensional delay-Doppler domain grid, enabling variable frame aspect ratios and reduced peak-to-average power ratio (PAPR) through techniques like DFT precoding and the use of a guard grid without cyclic prefixes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional wireless communication methods are used, then bandwidth utilization is limited, but accommodating rapid growth in data traffic becomes difficult
Solution Approach 1:
The patent transitions from traditional time-frequency domain resource allocation to delay-Doppler domain resource allocation. This dimensional change allows for more efficient spectrum utilization by exploiting the delay and Doppler dimensions, thereby accommodating higher data traffic capacity without requiring additional bandwidth.
Solution Approach 2:
The patent employs variable frame aspect ratios in the delay-Doppler domain, dynamically adjusting the number of delay bins and Doppler bins based on channel conditions and traffic requirements. This parameter adaptation enables flexible bandwidth utilization and optimizes data traffic capacity for different scenarios.
2Productivity
If OTFS modulation with variable frame aspect ratio is implemented, then resource allocation efficiency improves, but system complexity increases
Solution Approach 1:
The patent implements dynamic frame aspect ratio adjustment where the number of delay bins and Doppler bins can be varied based on transmission requirements. This dynamic configuration allows the system to optimize resource allocation for different traffic patterns and channel conditions without requiring complete system redesign.
Solution Approach 2:
The patent segments the delay-Doppler resource grid into configurable blocks with variable aspect ratios. By dividing resources into manageable segments that can be independently configured, the system achieves flexible resource allocation while maintaining manageable complexity through modular design.
3Loss of substance
If DFT precoding and guard grid are used without cyclic prefixes, then overhead is reduced, but implementation complexity increases
Solution Approach 1:
The patent extracts and removes the cyclic prefix component from the traditional OFDM structure, replacing it with a guard grid in the delay-Doppler domain. This extraction eliminates the overhead associated with cyclic prefixes while maintaining the necessary guard functionality through the DFT precoded guard grid structure.
Solution Approach 2:
The patent substitutes the mechanical cyclic prefix insertion mechanism with a DFT-based precoding operation in the delay-Doppler domain. This substitution replaces time-domain signal replication with frequency-domain transformation, reducing overhead while managing complexity through efficient DFT computation.
4Reliability
If OTFS modulation is implemented, then frequency and time diversity is achieved, but peak-to-average power ratio increases
Solution Approach 1:
The patent employs DFT precoding that transforms the signal representation in the delay-Doppler domain, which inherently reduces the peak-to-average power ratio. By changing the parameter representation from time-frequency to delay-Doppler with DFT precoding, the system achieves frequency and time diversity while maintaining lower peak power requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
OTFS modulation enhances communication reliability and efficiency by achieving low PAPR, reducing overhead, and providing frequency and time diversity, leading to improved packet error rates and link budgets compared to traditional methods like SC-FDMA.
Implementation Method 1
The transmitter may map digital data to a digital amplitude modulation constellation in a time-frequency space. The digital amplitude modulation constellation may be mapped to a delay-Doppler domain and the transmitter may transmit to the surface according to an orthogonal time frequency space modulation signal scheme
Implementation Method 2
The surface may generate an electrical signal from an electromagnetic signal
Data Source
AI summary
Device, methods and systems for implementing aspects of orthogonal time frequency space (OTFS) modulation in wireless systems are described. In an aspect, the device may include a surface of an object for receiving an electromagnetic signal. The surface may be structured to perform a non-electrical function for the object. The surface may generate an electrical signal from an electromagnetic signal. The electromagnetic signal may be received from a transmitter. The transmitter may map digital data to a digital amplitude modulation constellation in a time-frequency space. The digital amplitude modulation constellation may be mapped to a delay-Doppler domain and the transmitter may transmit to the surface according to an orthogonal time frequency space modulation signal scheme. The apparatus may further include a demodulator to demodulate the electrical signal to determine digital data.