Novel SISO Detection Algorithms for Nonlinear Satellite Channels

Abstract

Abstract-We propose novel detection algorithms for linear modulations transmitted over nonlinear satellite channels. These algorithms are derived by using a Volterra-series expansion of the useful signal and by applying the sum-product algorithm to a suitably-designed factor graph. Being soft-input soft-output (SISO) in nature, the proposed detectors can be adopted in turbo processing without additional modifications. When compared with the optimal detection algorithm for these channels, whose complexity is exponential in the channel memory, the proposed schemes result very appealing in terms of tradeoff between performance and computational complexity. Particularly, they can approach the optimal performance with a complexity only linear in the channel memory.

Improving the Spectral Efficiency of Nonlinear Satellite Systems through Time-Frequency Packing and Advanced Receiver Processing

“…In this work, we consider detection based on an approximate signal model described in [15], which comes from a simplified Volterra series expansion of the nonlinear channel. In the following, we will consider PSK and amplitude/phase shift keying (APSK) modulations typically employed in satellite systems [1].…”

“…Hence, we assume that, apart from AWGN, only user = 0 is present and that the simplified model (9) holds. Optimal single-user MAP symbol detection for this case can be performed through a bank of filters followed by a conventional Bahl-Cocke-Jelinek-Raviv (BCJR) detector [23] with proper branch metrics and working on a trellis whose number of states exponentially depends on the channel memory [15].…”

“…We consider two different approaches to detection for nonlinear channels, namely the use of a detector taking into account the nonlinear effects and a more traditional scheme based on predistortion and memoryless detection. In the case of predistortion, we consider the dynamic data predistortion technique described in [12], [13], whereas in the case of advanced detection we consider the receiver in [14] employing the channel shortening technique (CS), recently proposed for nonlinear satellite channels and designed based on an approximate signal model proposed in [15]. It should be noted that we apply the TF packing technique to nonlinear satellite channels for which, usually, even by using RRC pulses there is still ISI at the receiver.…”

Distortion modeling and analysis for multilevel coded APSK with memoryless nonlinearity

“…These approaches impose a transmitter side operation which may require considerable amount of computation. On the other hand, an iterative detection algorithm considering nonlinear distortion at the receiver side is developed in [11].…”

Low complexity predistortion and equalization in nonlinear multicarrier satellite communications

“…The uplink bandwidth restriction has motivated the multicarrier data DPD for satellite HPAs in [5] where a general multicarrier memory polynomial data predistorter algorithm was formulated. On the other hand, nonlinear iterative interference cancellation EQ techniques have been proposed in the area of satellite communications in [6,26] for single carrier applications, while in [4] a turbo equalization method is provided for multicarrier satellite channels. In common broadcast applications involving multicarrier systems, the gateway (GW) has access to all carriers while the user terminal can decode only one carrier.…”