Analytic Analysis of Narrowband IoT Coverage Enhancement Approaches

TL;DR

This paper provides an analytical framework for understanding and optimizing coverage enhancement techniques in NB-IoT, focusing on transmission strategies, bandwidth, and energy efficiency, supported by a novel uplink link adaptation algorithm.

Contribution

It introduces analytical expressions for NB-IoT transmission approaches and proposes an uplink link adaptation algorithm considering coverage extension strategies.

Findings

Transmission approaches significantly impact coverage and energy efficiency.

The analytical model accurately predicts the influence of different configurations.

The proposed adaptation algorithm improves uplink coverage performance.

Abstract

The introduction of Narrowband Internet of Things (NB-IoT) as a cellular IoT technology aims to support massive Machine-Type Communications applications. These applications are characterized by massive connections from a large number of low-complexity and low-power devices. One of the goals of NB-IoT is to improve coverage extension beyond existing cellular technologies. In order to do that, NB-IoT introduces transmission repetitions and different bandwidth allocation configurations in uplink. These new transmission approaches yield many transmission options in uplink. In this paper, we propose analytical expressions that describe the influence of these new approaches in the transmission. Our analysis is based on the Shannon theorem. The transmission is studied in terms of the required Signal to Noise Ratio, bandwidth utilization, and energy per transmitted bit. Additionally, we propose an uplink link adaptation algorithm that contemplates these new transmission approaches. The conducted evaluation summarizes the influence of these approaches. Furthermore, we present the resulting uplink link adaptation from our proposed algorithm sweeping the device's coverage.