Real-time adaptive LDPC coded APSK for aeronautical telemetry

In this paper, we consider the design of capacity-approaching forward error correction (FEC) coded amplitude phase shift keying (APSK) modulation schemes for use in the aeronautical telemetry. By maximizing the mutual information, we first investigate the designs of APSK modulations suitable for communication over nonlinear wireless channels. Then we propose a unified FPGA-based hardware-efficient architecture which combines the capacity-approaching LDPC decoders with four APSK modulation formats, including Gray-mapping-based 8-APSK, 16-APSK, 32-APSK, and 64-APSK. The proposed architecture allows the flexibility of the FEC-encoded signal to be received by legacy test-range systems. The emulation results show that such an LDPC-coded modulation scheme can adapt to wide range of received signal-to-noise ratios, ranging from 9.4 dB to 21.4 dB, by using different LDPC codes and/or modulation formats.