FC-OFDM Modulation for Multi-Service Transmission
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Solution Overview
Problem
Current multi-carrier modulation techniques, such as those used in LTE, face challenges in maintaining orthogonality and spectral efficiency, especially in scenarios with high Doppler effects and varying communication speeds, and are not suitable for simultaneous processing of diverse services like MBB, IoT, V2X, and MCC, leading to inefficiencies and losses in bandwidth and reliability.
Innovation Solution
A new multi-carrier modulation format is introduced, which includes a cyclic prefix and/or postfix forming a cyclic extension of L samples, combined with filtering on M + L samples, to enhance robustness against synchronization absences and maintain orthogonality, while reducing secondary lobes and concentrating the spectrum, thus supporting simultaneous processing of different communication services.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional OFDM modulation is used for multi-service transmission, then spectral efficiency can be maintained for MBB services, but orthogonality is lost and reliability deteriorates when high Doppler effects are present
Solution Approach 1:
The patent segments the transmission resource into multiple sub-bands, with the first sub-band using FC-OFDM modulation for reliable transmission under high Doppler effects, and the second sub-band using traditional OFDM for spectral efficiency in normal conditions. This segmentation allows different modulation schemes to serve different services and channel conditions simultaneously.
Solution Approach 2:
The patent dynamically adapts the modulation scheme based on channel conditions and service requirements. The base station determines whether to use FC-OFDM or traditional OFDM for each terminal based on real-time feedback and service type, allowing the system to optimize between reliability and spectral efficiency dynamically.
2Productivity
If a single modulation scheme is used for all services, then device complexity is reduced, but spectral efficiency and reliability deteriorate for specific services
Solution Approach 1:
The patent creates a universal transmission framework that can handle multiple service types (MBB, IoT, V2X, MCC) with a single FC-OFDM implementation. The first sub-band configuration with FC-OFDM provides a unified solution for services requiring high reliability, while the second sub-band handles spectral efficiency requirements, eliminating the need for separate modulation schemes for different services.
3Reliability
If traditional OFDM is used without cyclic extension filtering, then transmission simplicity is maintained, but spectral leakage increases and orthogonality is compromised
Solution Approach 1:
The patent applies preliminary filtering to the cyclic extension portion of the signal before transmission. By pre-filtering the cyclic extension in the time domain, the system prevents spectral leakage and maintains orthogonality between sub-carriers, addressing the spectral leakage issue before it affects transmission quality.
Data Source
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AI summary
The present invention pertains to a method (1) implementing one and the same frequency time transform (IFFT) of size M whatever the service. The method adds (+FIXs) during a framing a cyclic extension of L = L 1 + L 2 samples to obtain a sequence ofM + L samples. The method performs a temporal filtering (WDG) according to a function f(n) of the samples n of the sequence ofM + L samples.