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Method to perform modulation over pilot symbols in communications systems employing quadrature amplitude modulation (QAM).
About
CONTEXT In modern coherent optical communication systems employing quadrature amplitude modulation (QAM), the use of pilot symbols is very common to aid on the estimation and compensation of carrier-phase noise. These pilot symbols are composed of QAM symbols with pre-defined amplitude and phase, which are known a priori both by the transmitter and receiver. Pilot symbols are time-multiplexed with regular data symbols (payload), typically in a regularly distributed fashion. In order to circumvent this loss of information rate imposed by the use of pre-defined pilot symbols, we propose the use of embedded data modulation, in which the amplitude (and possibly also the phase) of the pilot symbols can be modulated, while keeping their underlying properties. This allows to increase the information rate of the transmission system without incurring into additional complexity and/or performance penalty. APPLICATIONS - Optical fiber links - High-capacity (up to 100 Gbps) coherent transceivers - Any QAM-Based Transmission Systems Employing Pilot Symbols (RF, Wireless, Optical) BENEFITS - INCREASED TRANSMITTER INFORMATION RATE which can be utilized to improve the performance of the transmission system in various ways: - DIRECT INCREASE OF BIT-RATE for the same symbol-rate, modulation format, coding-rate and pilot-rate of the transmission rate - IMPROVEMENT OF REQUIRED SNR for operation, while keeping the same net bit-rate DEVELOPMENT STAGE TRL 6 - The prototype system was tested in intended environment, with performance close to expected. INTELLECTUAL PROPERTY Provisional patent application filed in Portugal (priority date: 24/05/2021) COMMERCIAL OFFERING - Licensing or assignment agreement - Testing new applications - Joint further developments TARGET MARKET Instituto de Telecomunicações seeks manufacturers of telecommunications equipment, producing coherent optical transceivers. SCIENTIFIC PUBLICATIONS F. P. Guiomar, B. M. Oliveira, M. S. Neves, M. A. Fernandes, and P. P. Monteiro, “Squeezing Out the Achievable Information Rate From Coherent QAM Systems Through Amplitude Modulation of CPE-Pilots”, in Proc. Optical Fiber Conference (OFC), paper F4D.4, Fully-Virtual Event, March 2021. #OpticalNetworks #DigitalSignalProcessing #PilotSymbols #QuadratureAndAmplitudeModulation #QAM TECHNOLOGY ID PI-1026
Key Benefits
- INCREASED TRANSMITTER INFORMATION RATE which can be utilized to improve the performance of the transmission system in various ways: - DIRECT INCREASE OF BIT-RATE for the same symbol-rate, modulation format, coding-rate and pilot-rate of the transmission rate - IMPROVEMENT OF REQUIRED SNR for operation, while keeping the same net bit-rate
Applications
- Optical fiber links - High-capacity (up to 100 Gbps) coherent transceivers - Any QAM-Based Transmission Systems Employing Pilot Symbols (RF, Wireless, Optical)