Simple iterative decoding for bit-interleaved coded orthogonal modulation

Turbo-FSK: A new uplink scheme for low power wide area networks

“…For a BER of 10 −5 , Turbo-FSK with N = 1023 shows 6.6dB of gain versus repeated 8-FSK and 7.8dB gain over repeated BPSK. This BER is reached for a E b /N 0 of 1.8dB (case N = 1023), and can be compared to the BICM-ID scheme with a similar spectral efficiency presented in [15] (using N = 65536). Our scheme shows an improvement of 1dB over BICM-ID, while using a much smaller block size.…”

“…Moreover, using larger values of N would improve the performance for every case. BICM-ID from [15] is shown on the graph. Results are obtained using a 64-state convolutional code, involving a high decoding complexity due to the Soft-Output Viterbi Algorithm combined with the turbo processing of BICM-ID.…”

“…Demodulation may simply be based on Fast-Fourier-Transform (FFT) as in an Orthogonal-Frequency-Division-Multiplexing receiver [13]. FSK has been exploited in a turbo coding scheme, Bit-Interleaved Coded Modulation with Iterative Decoding (BICM-ID) (see [14], [15]), where the steps of binary channel coding and M -ary FSK modulation are separated by an interleaver to ensure diversity at the receiving side. The receiver shares information of the decoded soft bits between the decoder and the orthogonal soft demodulator.…”

“…In this paper, we propose a new scheme called Turbo-FSK, and perform its analysis. Unlike [15], where a binary coding step was performed before FSK signaling, the new idea is to directly consider FSK signals as codewords. This scheme is an extension of the Turbo Hadamard scheme from [10] to the FSK modulation, replacing the binary Hadamard codes by the FSK waveforms.…”