5G Contender Waveforms for Low Power Wide Area Networks in a 4G OFDM Framework

When designing new solutions for Low Power Wide Area (LPWA) networks, coexistence and integration into existing 4G frameworks should be considered to ease the deployment procedure and reduce costs. In a previous work, Turbo-Frequency Shift Keying (FSK) was proposed as a potential physical layer for LPWA networks. We propose to study the system in the Orthogonal Frequency Division Multiplexing (OFDM) framework, currently used by existing cellular networks and also considered for the recently standardized Narrow-Band IoT. The new architectures of the Turbo-FSK transmitter and receiver are presented. Simulations are run under various conditions including Rayleigh fading channel with mobility, demonstrating the Turbo-FSK scheme to achieve performance close to Turbo-Coded OFDM. The scheme also exhibits a constant envelope, which may multiply the Power Amplifier (PA) efficiency by up to a factor of 2 and makes the solution a promising candidate for 5G LPWA transmission.