Subcarrier Index Modulation (SIM)-Orthogonal Frequency Division Multiplexing (OFDM) based superposition coded modulation method

Abstract

The invention belongs to the communication anti-jamming technical field, relates to a Superposition Coded Modulation (SCM) communication system, Subcarrier Index Modulation (SIM) and a related time domain detection technology of the SIM and discloses an SIM-OFDM based superposition coded modulation method. By referring to SIM-OFDM ideas and spatial modulation (SM) ideas, one part of a series of bit data is used for transmission, one part is used as index bits, the index bits determine how the sent data select weighted values, the sent data are multiplied by the selected weighted values and then transmitted to channels to be subjected to noise adding, a maximum likelihood method is used at the receiving end to calculate a posterior probability of each weighted value, and accordingly, the index bits and the selected weighted values can be obtained. According to the method, the SCM superposition layers are decreased, the complexity is reduced, and the bit error rate performance is maintained to some extent and even improved.

Description

technical field [0001] The invention belongs to the technical field of communication anti-jamming, and relates to a superposition coded modulation (Superposition Coded Modulation, SCM) communication system, a subcarrier index modulation (Subcarrier Index Modulation, SIM) and related time domain detection technology. Background technique [0002] In noisy channels, coded modulation can be efficiently and reliably transmitted, such as early trellis coded modulation (TCM) and multilevel coded modulation, which can get better performance gains when combined with binary coded multi-ary signals. And bit-interleaved coded modulation (BICM) can obtain better performance with a relatively simple method. The Superposition Coded Modulation (SCM) can be regarded as a special case of BICM. The detection complexity of BICM system increases exponentially with the number of transmitted bits, while the complexity of SCM increases with the increase of the number of layers, and the performanc...

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Problems solved by technology

[0004] In SCM, the more layers are superimposed, the lower the power allocated to each layer, the more serious the interference between layers, and the more difficult it is for the receiving end to distinguish the signals of each layer. If the information of each layer cannot be distinguished , it cannot be divided and merged, so the performance is less and less obvious as the number of superimposed layers increases

[0005] The present invention draws on the ideas of SIM-OFDM and spatial modulation (spatial modulation, SM) to provide a SIM-OFDM-based superposition coding modulation method, so that the sending end of the SCM can follow certain rules in each time slot. Select a part of the number of layers to send data, making it easier for the receiving end to distinguish the signals of each layer, and solve the problem that the performance of the current SCM increases with the increase in the number of superimposed layers.

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