Low complexity demodulation method for multiple-input multiple-output carrier sequence modulation system

Abstract

The invention provides a low complexity demodulation method for a multiple-input multiple-output carrier sequence modulation system. Dimensionality reduction MMSE estimation is used for each activation mode of each subcarrier in a signal subframe, modulation symbol estimation under each activation mode is obtained, and a corresponding complete estimation vector is formed according to the activation mode; the activation mode and the modulation symbol of each subcarrier are obtained through using an MAP criterion, estimation results of subcarriers form a complete signal subframe according to a sequence, and after activation mode detection on the signal subframe and error activation mode correction, a signal subframe with a legal activation mode is demodulated to obtain an information bit. The MMSE criterion is firstly used to estimate the modulation symbol under each activation mode, the MAP criterion is then used to calculate the maximum posteriori probability of different transmissionvectors under each activation mode, and through considering the posteriori probabilities of different transmission vectors, the estimation accuracy of each subcarrier is enhanced, and the error bit performance of the system is improved.

Description

technical field [0001] The invention relates to digital wireless communication technology, in particular to a low-complexity demodulation method for a multiple-input multiple-output carrier number modulation system. Background technique [0002] Multiple-input multiple-output (MIMO) is a multi-antenna communication system, which can greatly improve system capacity and bit error performance compared with traditional single-antenna systems. Due to the high throughput of the MIMO system, the channel capacity of the system can be doubled without increasing the spectrum resources, making MIMO technology one of the core technologies of the next generation of wireless communication. [0003] Orthogonal frequency division multiplexing with index modulation (OFDM-IM) is a novel multi-carrier transmission technology. As an improved technology of traditional OFDM, it is in line with the new green communication technology. In OFDM-IM technology, all subcarriers are no longer activated ...

AI Technical Summary

Problems solved by technology

In the MIMO-OFDM-IM system, the maximum likelihood (Maximum-likelihood, ML) receiver can achieve the best performance, but it needs to search all possible combinations, its computational complexity is related to the modulation symbol constellation order M, the number of transmitting antennas N t and the number of subcarriers per subframe in OFDM-IM N sub Related to the number of activations K, the computational complexity increases exponentially with the number of modulated transmit antennas, thus severely limiting the use of ML receivers in practical applications

Although the MMSE-LLR based on the MMSE criterion reduces the demodulation complexity, it has a greater performance loss compared to the ML receiver. Therefore, in applications that require real-time performance, a low-complexity and low-performance loss is required. receiver

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