A Novel Solution for NB-IoT Cell Coverage Expansion

Narrow Band Internet of Things (NB-IoT) is a technology, standardized in the 3rd generation partnership project (3GPP) to support for IoT connectivity. The conventional NB-IoT cell coverage is limited by maximum allowable round trip delay as well as maximum allowable propagation loss. While the propagation loss can be dealt with antenna heights, spectrum band, repeaters, and other solutions, the round trip delay specified in 3GPP limits the NB-IoT coverage up to 35 km. In this paper, we propose a novel coverage expansion method called Narrow Band Timing Advance (NB-TA) which can support NBIoT cell coverage beyond 35km, and the feasibility of this solution was verified by an actual measurement campaign over an ocean environment.