Ber Characterization of Frequency-coded Multiple Rank Modulation

Abstract

The growing need for higher rates of data transmission has made Multiple-Output Multiple-Input (MIMO) systems become the main focus for communication systems. In this work, a signal transmission technique is proposed where information to the receiver is transmitted via different ranks of frequency subcarriers i.e., Frequency-Coded Multiple Rank Modulation (FMRM). In FMRM, the input information bits stream determines the number of subcarriers required. The ranking modulator receives a random bitstream of information as input. Instead of the channel index, the receiver detects the number of frequency subcarriers in an OFDM scheme. A system mapper is used to pre-set and know the pattern of frequency subcarriers at the receiver. The bits in the frequency domain can only be decoded using the rank information. A threshold detector that utilizes the optimal power required for detection, employed at the receiver, is used to accurately identify the transmitted signals. A desirable value for the threshold detector is obtained for both cases of Gaussian and Fading channels i.e., 0.6 and 0.3 respectively. Analytical upper constraints on the FMRM system's information-theoretic approach are derived for validation and then compared to simulation findings for related systems like Subcarrier Index Modulation (SIM) and alternative transmission techniques at similar data rates e.g., BPSK and M-QAM which show tractable performance (FMRM has a 9 dB) gain when compared with BPSK, a 6 dB gain when compared with 4-QAM and a 1 dB gain when compared with 8-QAM). When comparing different transmission data rates (1bit per second (bps), 2 bps and 3 bps), a signal to noise ratio deviation of approximately 6 dB is observed between a 1 bps and 2 bps transmission and similarly a deviation of approximately 9 dB is observed between 2 bps and 3 bps transmission. Further, the antenna correlation effect on the receive antennas is investigated and system performance is shown for the same vis a vis non-antenna correlation with a deviation of the two scenarios being approximately 4dB. In addition to the wireless channel, the frequency chains also modulate the information sent which improves transmission speeds, which not only makes the FMRM system better as a very reliable system for next generation wireless networks that are built on faster transmission speeds with very low latency but also makes FMRM a better system for use in information security operations.