Experimental Verification of Prototype Equalizer for Non-linear Compensation over Satellite Channel

Abstract

We propose an equalization technique that uses the characteristics of the satellite transponder to compensate for its non-linear distortion. In our previous study, the effects of this technique for 16APSK and 32APSK were assessed in simulations. In this study, we revised the configuration of the equalization system and developed a receiver based on this revision. We examined the reception performance of 16APSK and 32APSK in transmission experiments.

Development of Transmitter and Receiver With Set Partitioning 64APSK Coded Modulation Designed on Basis of Channel Capacity

“…Fig. 16 illustrates the experimental system with the 12-GHz-band satellite simulator [28], which consists of input/output multiplexer (IMUX/OMUX) filters with a center frequency of 12.03436 GHz and bandwidth of 34.5 MHz, a traveling wave tube amplifier (TWTA) without a linearizer, and variable attenuation to adjust the output back-off (OBO) [29] of the TWTA. The AM-AM and AM-PM characteristics of the TWTA are shown in Fig.…”

“…The OBO is an important parameter to evaluate transmission performance through a satellite transponder because it is related to the amount of non-linear distortion occurring in the TWTA. We define the OBO of the modulated signal as the ratio of the saturated maximum output power of a continuous wave to the operation output power of the modulated signal [28]. The optimal OBO for multi-level modulation transmission can be obtained when the required C/N + OBO is a minimum [28].…”

120-W Ku-Band GaN SSPA with Diode Linearizer for Future Broadcasting Satellites

“…block in the receiver means an adaptive equalizer based on the least-squares-error criterion [19]. Figure 3 shows the AM/AM and AM/PM characteristics of the TWTA, which are actual measurements from indoor tests [17]- [19]. In the case of the 120-W-class TWTA, the normalized output power of 0 dB corresponds to 120 W (50.8 dBm).…”

“…Thus, there is a trade-off between the gain of the amplifier and the linearity. Figure 4 shows the amplitude and group delay characteristics of the IMUX and OMUX filters, which are also actual measurements from the indoor tests [17]- [19]. The role of the IMUX is to filter a single carrier out of the other adjacent broadcasting waves [21].…”

“…Figure 17 shows a block diagram of the transmission system of our experiments. The dashed line marks the area of the 12-GHz-band satellite transponder in the satellite simulator composed of hardware [17]- [19]. We conducted transmission tests by replacing the TWTA with the SSPA inside this satellite simulator and evaluated the differences in transmission performance in the following channel models:…”