Multi-user sub-carrier index modulation orthogonal frequency-division multiplexing (SIM-OFDM) transmission method

Abstract

The invention discloses a multi-user sub-carrier index modulation orthogonal frequency-division multiplexing (SIM-OFDM) transmission method. At a sending end, logic blocking of sub-carriers is carried out by adoption of an orthogonal amplitude modulation order M at first; then, information bits of all users are also grouped correspondingly; each group is divided into two parts again; one part selects one sub-carrier in each block to enable the sub-carrier to be silent; the other part modulates the residual activated sub-carriers in each sub-block; due to inverse fast Fourier transform, parallel-serial conversion and addition of a cyclic prefix, an SIM-OFDM symbol is formed and sent; at a receiving end, logic grouping, which is the same as that at the sending end, of a detection signal output by a GAMP detector is carried out by adoption of a multi-user iterative detection method based on a generalized approximate message transferring algorithm under non-ideal channel state information; a symbol having the minimum power in each group is judged, so that the positions of silent sub-carriers are identified; index bits are recovered; and residual symbols are demodulated, so that digital modulation bits are obtained. By means of the multi-user sub-carrier index modulation orthogonal frequency-division multiplexing (SIM-OFDM) transmission method disclosed by the invention, the energy efficiency and the BER performance are improved.

Description

technical field [0001] The present invention relates to wireless communication technology, in particular to a multi-user subcarrier index modulation orthogonal frequency division multiplexing transmission method. Background technique [0002] As an extension of the traditional digital modulation method, spatial modulation (SM) is a single-carrier transmission method that requires only one radio frequency link, and only one antenna is activated to send modulation information at any time for all transmitting antennas, and the spatial position of the activated antenna is used to Transferring part of the information can improve energy efficiency while ensuring system frequency band utilization. [0003] OFDM technology has high spectral efficiency as a multi-carrier transmission method, but its disadvantage is that the peak-to-average power (PAPR) is relatively high. Extending the idea of ​​SM to the frequency domain, a single-user OFDM system based on SIM is proposed to reduce...

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Problems solved by technology

[0004] Compared with the traditional OFDM, the existing single-user SIM-OFDM has the advantages of reducing PAPR, improving energy efficiency, and helping to combat inter-subcarrier interference, but according to the principle of SIM-OFDM: the K subcarriers Carrier logic is equally divided into G sub-blocks, each sub-block contains n sub-carriers, and k sub-carriers are activated to transmit M-order modulation symbols, and the spectral efficiency is Generally less than the spectral efficiency of traditional OFDM η=log 2 M, resulting in a waste of spectrum; and at the receiving end of a single-user SIM-OFDM system, the maximum likelihood detection algorithm with high complexity or the minimum mean square error (MMSE) detection algorithm with unsatisfactory bit error performance is often used

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