Novel Codebook-Based MC-CDMA with Compressive Sensing Multiuser Detection for Sporadic mMTC

Massive machine type communication (mMTC) is one of the basic components of the future fifth generation (5G) wireless communication system. In mMTC, the information processing at the sensor nodes is required to be simple, low power consuming and spectral efficient. In order to increase the spectral efficiency at the cost of minimum performance loss and to simplify the information processing at the sensor node, in this paper a codebook based spreading technique is proposed. In the proposed scheme, first, the modulation and spreading are combined into a direct symbol-to-sequence spreader, which directly maps the input bits into a codeword from the user specific codebook. Secondly, utilizing the sporadic node activity of the mMTC a compressive sensing based algorithm is designed for multiuser activity and data detection. Exploiting the multidimensional structure of the codebook, the required signal to noise ratio (SNR) to increase the modulation order, is reduced as compared to the conventional scheme. Besides reducing the power consumption, it is shown that for modulation order of eight, the proposed scheme achieves a gain of 1 dB over the conventional scheme at bit error rate (BER) of 10^-5. However, more sophisticated decoding algorithm is required to achieve the performance gain at a lower modulation order.