Description
Simulation Codes of Multi-User Subcarrier Number Modulation-based OFDM (MU-OFDM-SNM)
Summary: Orthogonal Frequency Division Multiplexing with Subcarrier Number Modulation (OFDM-SNM) has recently been proposed as an effective transmission method that can transmit additional data bits by exploiting the number of subcarriers in each subblock. This results in improved robustness in terms of spectral efficiency and reliability. However, one of the main drawbacks of OFDM-SNM is that not all the available subcarriers are deployed to transmit data, as some of these subcarriers remain inactive. In order to eliminate this problem and make use of all the available subcarriers, Multi-User OFDM-SNM is proposed in this paper for serving multiple users by dedicating the subcarriers used for implementing SNM to serve a far user, whereas the remaining subcarriers are used to send data for a near user. In this paper, the concept of multi-user OFDM-SNM is established on the basis of conventional OFDM over a Rayleigh fading channel. The validity of the system is proven by exhibiting both theoretical analysis and computer simulations. The obtained results show that the proposed multi-user OFDM-SNM is a strong candidate for the future 6G and beyond technologies and it can satisfy the requirements of multi-user cases of future wireless systems demanding higher reliability and better spectral efficiency. Multi-User Subcarrier Number Modulation-based OFDM for Future Wireless Communication Networks · RS Open Journal on Innovative Communication Technologies (pubpub.org)
The main contributions of the proposed scheme can be summarized as follows:
1) The proposed transmission technique results in obtaining
high spectral efficiency and low BER by avoiding
the waste of subcarriers that remain inactive during the
operation of OFDM-SNM and creates an opportunity to
make use of those inactive subcarriers by another user.
2) Since OFDM-IM dictates the indices of the active sub-
carriers to transmit additional data bits, it suffers from
the inability to make the selection of the subcarriers
to be channel-dependent as the selected subcarriers’
indices are purely data-dependent. However, in OFDM-
SNM, the selection of the active subcarriers can be
operated by the number of subcarriers, which indicates
the data dependency, and also these active subcarriers
can be chosen from those subcarriers that have the
highest channel capacity. Thus the proposed scheme can
operate the transmission in a state being both channel
and data-dependent at the same time
3) The proposed multi-user scheme can also be adapted to
the other OFDM based modulation techniques such as
OFDM-IM, OFDM-SPM, and OFDM with subcarrier
gap modulation (OFDM-SGM) [38], since all these
schemes are suffering from the same drawback, which
is not deploying all the available subcarriers to transmit
data, as some of these subcarriers remain inactive and
lead to a waste of spectrum
