State Machine-Based Waveforms for Channels With 1-bit Quantization and Oversampling With Time-Instance Zero-Crossing Modulation

Systems with 1-bit quantization and oversampling are promising for the Internet of Things (IoT) networks because they can reduce the power consumption of the analog-to-digital-converters in the devices. The novel time-instance zero-crossing (TI ZX) modulation is a promising approach for IoT networks and devices but existing studies rely on optimization problems with high computational complexity and delay. In this work, we propose a practical waveform design based on the established TI ZX modulation for a multiuser multi-input multi-output (MIMO) systems in the downlink scenario with 1-bit quantization and temporal oversampling at the receivers. In this sense, the proposed temporal transmit signals are constructed by concatenating segments of coefficients which convey the information into the time-instances of zero-crossings according to the TI ZX mapping rules. The proposed waveform design is compared with other methods from the literature in terms of bit error rate and normalized power spectral density. Numerical results show that the proposed technique is suitable for multiuser MIMO systems with 1-bit quantization while tolerating some small amount of out-of-band radiation.