Sub-GHz LPWAN network coexistence, management and virtualization : an overview and open research challenges

The IoT domain is characterized by many applications that require low-bandwidth communications over a long range, at a low cost and at low power. Low power wide area networks (LPWANs) fulfill these requirements by using sub-GHz radio frequencies (typically 433 or 868 MHz) with typical transmission ranges in the order of 1 up to 50 km. As a result, a single base station can cover large areas and can support high numbers of connected devices (> 1000 per base station). Notorious initiatives in this domain are LoRa, Sigfox and the upcoming IEEE 802.11ah (or "HaLow") standard. Although these new technologies have the potential to significantly impact many IoT deployments, the current market is very fragmented and many challenges exists related to deployment, scalability, management and coexistence aspects, making adoption of these technologies difficult for many companies. To remedy this, this paper proposes a conceptual framework to improve the performance of LPWAN networks through in-network optimization, cross-technology coexistence and cooperation and virtualization of management functions. In addition, the paper gives an overview of state of the art solutions and identifies open challenges for each of these aspects

Efficient I/O joining and reliable data publication in energy harvested ISA100.11a network

Energy harvesting technologies have brought a paradigm shift in the industrial automation sector by procreating self-powered wireless input/output (I/O) devices. Unfortunately, current wireless technologies for industrial applications, such as ISA100.11a and WirelessHART, are yet far from supporting harvester powered I/O devices. Although several works have been conducted to address the requirements of energy harvested I/O devices, most of those have focused on minimizing the I/O energy consumption during the steady-state phase of the network. However, a very important aspect, the energy consumption during network joining that consumes a significant amount of energy, is overlooked in these works. In this paper, we therefore analyze the I/O energy consumption in ISA100.11a network during the joining phase in addition to that in normal operation to better understand the challenges of energy harvesting communications. Then, we propose an energy efficient network joining scheme to support harvester powered I/O devices in ISA100.11a network. The proposed scheme significantly reduces the joining delay when compared with the traditional ISA100.11a joining scheme. We also propose a reliable data transmission scheme for energy harvested I/O devices by utilizing spatial diversity that can outperform ISA100.11a data publication through significant improvement in packet reception