![]() ; ; et al in Communications, IET (2015), 9(16), 2053--2059 A digital predistortion (DPD) scheme is presented for non-linear distortion mitigation in multi-carrier satellite communication channels. The proposed DPD has a multiple-input multiple-output architecture ... [more ▼] A digital predistortion (DPD) scheme is presented for non-linear distortion mitigation in multi-carrier satellite communication channels. The proposed DPD has a multiple-input multiple-output architecture similar to data DPD schemes. However, it enhances the mitigation performance of data DPDs using a multi-rate processing algorithm to achieve spectrum broadening of non-linear operators. Compared to single carrier (single-input single-output) signal (waveform) DPD schemes, the proposed DPD has lower digital processing rate reducing the required hardware cost of the predistorter. The proposed DPD outperforms, in total degradation, both data and signal DPD schemes. Further, it performs closest to a channel bound described by an ideally mitigated channel with limited maximum output power. © 2015. The Institution of Engineering and Technology. [less ▲] Detailed reference viewed: 206 (1 UL)![]() ; Piazza, Roberto ![]() ![]() in IET Communications (2015), 9(15), 20532059 A digital predistortion (DPD) scheme is presented for non-linear distortion mitigation in multi-carrier satellite communication channels. The proposed DPD has a multiple-input multiple-output architecture ... [more ▼] A digital predistortion (DPD) scheme is presented for non-linear distortion mitigation in multi-carrier satellite communication channels. The proposed DPD has a multiple-input multiple-output architecture similar to data DPD schemes. However, it enhances the mitigation performance of data DPDs using a multi-rate processing algorithm to achieve spectrum broadening of non-linear operators. Compared to single carrier (single-input single-output) signal (waveform) DPD schemes, the proposed DPD has lower digital processing rate reducing the required hardware cost of the predistorter. The proposed DPD outperforms, in total degradation, both data and signal DPD schemes. Further, it performs closest to a channel bound described by an ideally mitigated channel with limited maximum output power. [less ▲] Detailed reference viewed: 177 (3 UL)![]() ; Piazza, Roberto ![]() ![]() in EURASIP Journal on Advances in Signal Processing (2015) Aiming to reduce the power/mass requirements in satellite transponders and to reduce mission costs, joint amplification of multiple carriers using a single high-power amplifier (HPA) is being considered ... [more ▼] Aiming to reduce the power/mass requirements in satellite transponders and to reduce mission costs, joint amplification of multiple carriers using a single high-power amplifier (HPA) is being considered. In this scenario, a careful investigation of the resulting power efficiency is essential as amplification is nonlinear, and multicarrier signals exhibit enlarged peak-to-average power ratio. Thus, operating the amplifier close to saturation vastly increases signal distortion resulting in a severe degradation of performance, especially for higher order modulations. This paper proposes a reduced-complexity digital predistortion (DPD) scheme at the transmitter and a corresponding equalizer (EQ) at the receiver to mitigate these nonlinear effects. Scenarios include both the forward as well as the return links. In particular, the paper exploits the MIMO Volterra representation and builds on a basis pursuit approach using a LASSO (least absolute shrinkage and selection operator) algorithm to achieve an efficient basis representation, avoiding large computational complexity, to describe the selection of predistorter/equalizer model. The work further compares and contrasts the two mitigation techniques taking various system aspects into consideration. The gains in performance and amplification efficiency demonstrated by the use of DPD/ EQ motivate their inclusion in next-generation satellite systems. [less ▲] Detailed reference viewed: 256 (1 UL)![]() Piazza, Roberto ![]() ![]() in Proceedings of 31st AIAA International Communications Satellite Systems Conference (ICSSC), (2013) On-board joint power amplification of multiple-carrier DVB-S2 signals using a single High-Power Amplifier (HPA) is an emerging configuration that aims to reduce flight hardware and weight. However ... [more ▼] On-board joint power amplification of multiple-carrier DVB-S2 signals using a single High-Power Amplifier (HPA) is an emerging configuration that aims to reduce flight hardware and weight. However, effects specific to such a scenario degrade power and spectral efficiencies with increased Adjacent Channel Interference caused by non-linear characteristic of the HPA and power efficiency loss due to the increased Peak to Average Power Ratio (PAPR). The paper studies signal processing techniques that counteract for both aspects enabling efficient multicarrier on board amplification. Digital pre-distortion (DPD) at the gateway and equalization (EQ) at the User Terminal are the designed avenues of attack to mitigate the non-linear effects and improve power as well as spectral efficiencies. This paper builds on our initial work in Ref.1 that performed a survey on the adaptability of various compensation techniques to the considered scenario and short-listed the most favourable ones. Preliminary performance analysis of these techniques was undertaken with Signal to Interference Ratio (SINR) as the figure of merit. The contribution of this work over Ref. 1 includes : (a) a full DVB-S2 chain is simulated with the chosen techniques with Total Degradation (TD) as the figure of merit and (b) a sensitivity analysis is performed to study the dependence of the pre-distortion/ equalization performance ( measured as TD) on the channel parameters. [less ▲] Detailed reference viewed: 328 (16 UL) |
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