Iterative soft-detection of Space-Time-Frequency Shift Keying

Inspired by the concept of Space-Time Shift Keying (STSK), the further evolved philosophy of Space-Time-Frequency Shift Keying (STFSK) was proposed for Multiple-Input-Multiple-Output (MIMO) wireless communications, where a beneficial diversity gain may be gleaned from three different domains, namely the space-, time- and frequency-domain. In this paper we proposed soft-detected STFSK in order to conceive its iterative decoding aided version combined with channel codes. Our results showed that the STFSK soft demodulator, which iteratively exchanges extrinsic information with channel codes, may decrease the required transmit power by approximately 3 dB at the E_b/N₀ of 10^-5, compared to hard-decision STFSK. Furthermore, the detection complexity of both the hard- and the soft-decision STFSK demodulator is quantified in terms of the number of multiplications and additions required for each detection iteration.