Turbo Receiver for Short-Block-Length Polar-Coded Direct-Access Satellite-IoT Systems

Anticipated direct-access satellite-communication links will be the key enabler for a plethora of new Internet of Things (IoT) applications in the field of smart farming, asset tracking, or emergency services, which are blocked by today’s limited cellular coverage. Extending the receiver-transmitter distance from a few kilometers to the nearest base station to hundreds of kilometers to a Low Earth Orbit (LEO) satellite is challenging especially given the tight cost and power budgets of IoT devices. Advanced digital-baseband processing can help to close the link as long as its impact on computational complexity is tolerable. In this work we analyze the latest advancements in high-performance soft-output Polar coding that support small packet sizes demanded by IoT devices and extend a recently proposed Satellite IoT (SIoT) physical layer by introducing Turbo detection. Simulation results demonstrate the superiority of Polar codes over SIoT-specific short-block length Low Density Parity Check (LDPC) codes showing a performance gain of up to 0.8 dB. The proposed Polar-based Turbo-detection provides an additional gain of 0.5 dB resulting in an overall performance gain of 1.3 dB over an LDPC-coded reference system.