Abstract: A method for design an optimized constellation set and labeling for satellite point to multi-point transmission systems including transmitters and receivers, wherein the transmitters are adapted to create signals overlay and are configured to allow simultaneous transmission of at least two different data streams (services) intended for users with different radio link qualities. In particular, N services are provided to users having a good radio link and a subset of services is maintained and guaranteed for the users having a lower radio link quality condition.

Abstract: A method for design an optimized constellation set and labeling for satellite point to multi-point transmission systems including transmitters and receivers, wherein the transmitters are adapted to create signals overlay and are configured to allow simultaneous transmission of at least two different data streams (services) intended for users with different radio link qualities. In particular, N services are provided to users having a good radio link and a subset of services is maintained and guaranteed for the users having a lower radio link quality condition.

Abstract: A data detection method, having the steps of: a. receiving a signal transmitted over a communication channel, the signal being representative of at least a stream of interfering symbols xk, each representing one or more bits of a transmitted message; b. filtering the received signal through at least a filter bank having at least a first filter representative of a linear response of the channel and a second filter representative of a non-linear response of the channel, and sampling the filtered signals at the symbol rate, thus obtaining respective sequences of filtered samples rk(1) rk(3); and c. jointly computing the a posteriori probabilities of N>1 consecutive symbols xk. A data detector for carrying out such a method, and a method of transmitting data over a nonlinear channel, optimizing spectral efficiency when data detection is performed using such a method is also provided.

Abstract: A data detection method, having the steps of: a. receiving a signal transmitted over a communication channel, the signal being representative of at least a stream of interfering symbols xk, each representing one or more bits of a transmitted message; b. filtering the received signal through at least a filter bank having at least a first filter representative of a linear response of the channel and a second filter representative of a non-linear response of the channel, and sampling the filtered signals at the symbol rate, thus obtaining respective sequences of filtered samples rk(1) rk(3); and c. jointly computing the a posteriori probabilities of N>1 consecutive symbols xk. A data detector for carrying out such a method, and a method of transmitting data over a nonlinear channel, optimizing spectral efficiency when data detection is performed using such a method is also provided.

Abstract: A hybrid carrier frequency offset estimator that uses data-aided and non-data-aided signal processing techniques to produce multiple candidates for the carrier frequency offset within a return channel receiver in a DVB-RCS system using turbo coding and quadrature phase shift keying (QPSK) data modulation. In this system, the invention is employed to estimate signal distortion caused by carrier frequency offset so that this particular source of signal distortion can be removed to improve the ability of the receiver to maintain synchronization in low signal-to-noise conditions. This, in turn, allows the receiver to meet the DVB-RCS performance target, measured in terms of packet loss ratio, in low signal-to-noise ratio conditions and in particular for burst-mode data transmission with a short data packet size.

Abstract: A joint synchronizer and decoder that implements two decision aided processes, which are referred to as “decision aided candidate selection” and “decision aided synchronization and decoding.” Decision aided candidate selection may be used to select a carrier frequency offset by selecting among a number of candidates for this parameter based on an indication of decoding success. Decision aided synchronization and decoding may be used for phase tracking based on an indication of decoding success. Although these joint synchronizing and decoding techniques may be implemented together, they may also be implemented independently. The joint synchronizer and decoder may be implemented within a return channel receiver in a DVB-RCS system using turbo coding and quadrature phase shift key (QPSK) data modulation.