Raghavendra, R.Shripathi Acharya, U.S.2026-02-052019Physical Communication, 2019, 34, , pp. 174-18718744907https://doi.org/10.1016/j.phycom.2019.03.009https://idr.nitk.ac.in/handle/123456789/24537Space–frequency codes (SFC) having error correcting structure can be used to enhance the bit error rate (BER) performance of modern wireless systems (5G and beyond) employing multiple-input multiple-output (MIMO) and multi-carrier communication. In this work, the construction of non-orthogonal space–frequency block codes (NSFBC) from (n,k) cyclic codes has been proposed. In which, n represents the number of symbols in the codeword and k represents the number of symbols in the information sequence. The performance of proposed codes has been evaluated in MIMO systems employing orthogonal frequency division multiplexing and index modulation (MIMO-OFDM-IM). We initially obtained (n,k) full rank cyclic codes for any 1<k<?[Formula presented]? using Galois field Fourier transform (GFFT) description of (n,k) cyclic codes over F <inf> q m </inf> . Further, NSFBCs are obtained from full rank codes using Rank preserving maps. In a 2 × 2 system and a 10-path MIMO channel, the proposed full rank NSFBC with rank-preserving IM mapping (FR-NSFBC-IM), over F <inf> 5 2 </inf> , provides he similar BER performance when compared to MIMO-OFDM-IM system with Rate-1 Alamouti code and QPSK. Moreover, it provides an improvement in spectral efficiency of about 0.9 b/s/Hz. When compared to the MIMO-OFDM-IM with BPSK, FR-NSFBC-IM codes over F <inf> 5 2 </inf> provide an asymptotic SNR gain of about 1 dB and also the spectral efficiency has been improved by about 0.6 b/s/Hz. In the 4 × 4 scenario, full rank NSFBCs over F <inf> 5 4 </inf> with rank deficient IM mapping (RD-NSFBC-IM) provide an improvement in spectral efficiency of about 1.3 b/s/Hz. However, BER performance is similar to that of MIMO-OFDM-IM with BPSK. © 20195G mobile communication systemsBinary phase shift keyingBit error rateBlock codesCarrier communicationCommunication channels (information theory)EfficiencyGain controlOrthogonal frequency division multiplexingPhotomappingSignal to noise ratioFrequency block codesFull rank codesGalois fieldsMIMO-OFDMRank deficient codesMIMO systems