  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.
