Hybrid FQAM Modulation for Wireless Signal Transmission
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Solution Overview
Problem
Current wireless communication systems face limitations in channel capacity and interference cancellation, particularly at cell edges, where non-Gaussian interference signals can lead to reduced decoding performance compared to Gaussian channels, and existing technologies focus on interference cancellation at the receiving end rather than the transmitting side.
Innovation Solution
The implementation of a hybrid Frequency Shift Keying (FSK) and Quadrature Amplitude Modulation (QAM) Modulation (FQAM) scheme that combines the high spectral efficiency of QAM with the non-Gaussian characteristics of FSK, addressing pilot contamination by using an active tone that either avoids or attenuates interference between adjacent cells, and employing a Complex Generalized Gaussian probability density function for improved channel estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a Quadrature Amplitude Modulation (QAM) scheme is used to make interference signal characteristic close to Gaussian distribution, then decoding complexity is reduced, but channel capacity is decreased compared to non-Gaussian channels
Solution Approach 1:
The patent combines QAM and FSK modulation schemes into a hybrid modulation system. The QAM component provides Gaussian-like interference characteristics for simplified decoding, while the FSK component introduces non-Gaussian characteristics that increase channel capacity. This merging allows the system to achieve both low decoding complexity and high channel capacity simultaneously.
Solution Approach 2:
The hybrid modulation signal can be viewed as a composite signal structure where QAM and FSK components are integrated. The QAM part contributes to Gaussian interference characteristics, while the FSK part provides non-Gaussian properties, creating a composite modulation scheme that leverages the advantages of both individual schemes.
2Reliability
If interference cancellation is performed at the receiving side, then decoding performance can be improved, but system complexity and processing requirements increase
Solution Approach 1:
The patent performs interference cancellation at the transmitting side before signal transmission, rather than at the receiving side after reception. This preliminary action removes interference from the signal before it propagates through the channel, reducing the processing burden on the receiver and overall system complexity while maintaining decoding performance.
Solution Approach 2:
The patent converts the harmful interference between adjacent cells into a beneficial structure by coordinating pilot signals and using interference cancellation at the transmitter. What would normally be destructive interference is transformed into a controlled element that can be managed and even utilized to improve overall system performance.
3Measurement precision
If pilot signals are transmitted in adjacent cells, then channel estimation can be performed, but pilot contamination occurs reducing estimation accuracy
Solution Approach 1:
The patent applies preliminary anti-action by performing interference cancellation at the transmitting side before pilot signals are transmitted in adjacent cells. This pre-processing step removes or reduces the harmful pilot contamination effects before they can affect channel estimation accuracy in neighboring cells, allowing accurate channel estimation to be maintained across the network.
Data Source
Figure 1(a)~3b
Figure 4a~6a
Figure 6b~7
AI summary
A method of transmitting a signal using a plurality of modulation and coding schemes by a transmitter in a wireless communication system is provided. The method includes when a position of an active tone hits a position of a pilot tone of an adjacent cell, the active tone corresponding to a tone boosted through an application of a hybrid Frequency Shift Keying (FSK) and Quadrature Amplitude Modulation (QAM) Modulation (FQAM) scheme among tones included in an FQAM symbol based on the FQAM scheme in which a QAM scheme and a FSK scheme are combined, detecting two or more tones, which do not hit the position of the pilot tone among the tones included in the FQAM symbol, and transmitting signals by using the detected two or more tones.