End-to-End Error Control Coding Capability of NB-IoT Transmissions in a GEO Satellite System with Time-Packed Optical Feeder Link

Joan Bas,Alexis A Dowhuszko

doi:10.1007/978-3-030-71061-3_5

Abstract

This paper focuses on the return link of a GEO satellite system that collects information from a large number of sparsely distributed IoT devices in a large geographical area. Narrow-Band (NB) IoT transmissions, with suitable Modulation and Coding Scheme (MCS), are Detected-and-Forwarded onboard the satellite, mapping each QAM symbol of the radio access link (uplink) into another PAM symbol that modulates optical feeder link’s intensity (downlink). Given the massive number of IoT devices that is expected to be served by the GEO satellite system, the feeder link (downlink) of the return channel is expected to be the bottleneck. To tackle this limitation, time-packing signaling is used in the waveform that modulates the intensity of the optical feeder link (downlink); this way, the symbol time is reduced, and the number of IoT devices that can be simultaneously served in the radio access link (uplink) can augment without increasing the signal bandwidth in the optical feeder link. The Inter-Symbol Interference (ISI) that the time-packed feeder link generates is partially mitigated in the satellite gateway, using for this purpose an adaptive linear equalizer. After optical-to-electrical conversion, the NB-IoT codewords that are received in the gateway are decoded, correcting simultaneously errors introduced in both radio access and optical feeder links. The aim of this paper is to evaluate the error correction capability that MCS of NB-IoT standard has when used to protect end-to-end the hybrid radio/optical return link that results, particularly when using large overlapping factors in the optical feeder link to increase its achievable data rate.KeywordsHigh-Throughput SatelliteOptical feeder linkNarrow-Band IoTReturn channelTime-packingModulation and coding

Highlights

The improvement of spectral efficiency is key for achieving higher data rate links in the generation of wireless communication systems
We should expect that the lower is the code rate, the better is the Bit Error Rate (BER). This conclusions is valid at high Eb/N0, since the redundancy that introduces the channel coding may increase the number of erroneous bits after its iterative decoding process at lower values of Eb/N0
This paper studied the use of time-packing in the feeder link of a NB-IoT satellite system, which relied on optical wireless technology to implemented the downlink transmission from the satellite to the gateway

Summary

Introduction

The improvement of spectral efficiency is key for achieving higher data rate links in the generation of wireless communication systems. This fact becomes critical in Satellite Communications (SatCom) and IoT systems, where. The link propagation delay is large and the orders of the modulation schemes that are available for communication are low. In this regard, the Faster-ThanNyquist (FTN) transmission technique proposed by Mazo in [12], which is known as time-packing, has been recently reconsidered as a good candidate solution for increasing the spectral efficiency of Beyond 5G [14]. Timepacking is a good candidate solution to fulfill these two IoT requirements, when relying on SatCom systems with extremely large coverage areas

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Results

Conclusion