These properties can lead to the low-power consumption, long battery life, low launch costs, and simple antenna designs. They have shorter transmission delay and lower path loss than geostationary Earth orbit (GEO) satellite systems having the cost burden of high capital expenditure (CAPEX) and operational expense (OPEX). LEO satellite communication systems can be used to interoperate in hybrid terrestrial-satellite systems. Additionally, the huge capital of companies and investors now has room to invest in the satellite industry. However, satellite technology has considerably evolved over the past 20 years, and companies have developed creative business model that generate revenue from connections. However, most of them failed owing to financial problems. In the 1990s, the conventional companies, such as Iridium, Globalstar, and Orbcomm, tried to provide global connectivity. Cost-effective and easy-to-deploy large-scale satellite networks are being established. ![]() ![]() However, IoT transmission over low-Earth orbit (LEO) satellites has being proposed as the commercial solutions from several global satellite companies, such as Starlink by SpaceX, Telesat, and Kuiper by Amazon. Especially, densely deploying base stations on the ocean is difficult and requires the multihop systems using vessels and unmanned aerial vehicles (UAVs). Unlike the satellite networks, the terrestrial wireless networks are challenging to expand the service range owing to the technical problems and lack of a revenue model. However, some particular services in rural and remote areas, such as marine services, air travel, oil and gas, and remote farming, will require satellite links that can offer global coverage. For unlicensed bands, low-power wide-area (LPWA) networks, such as LoRa, Sigfox, and Ingenu, are widely deployed for specific IoT services. For licensed bands, narrowband IoT (NB-IoT), created by the 3rd Generation Partnership Project (3GPP), is the representative IoT standard, and it is able to use the infrastructure of conventional 3GPP networks, such as 2G, 3G, and 4G. It is also certain that the IoT will play a key role in the evolution toward future wireless communication.Ĭonnected devices can be deployed in either licensed or unlicensed bands, such as the industrial, scientific, and medical bands and TV white space, respectively. In industry, the monitoring of remote sensors and assets is increasingly required to reduce operational costs and increase productivity in various areas, such as smart agriculture, public utilities, and fleet tracking. ![]() Today, connected devices take charge of much of our daily lives. The concept of the Internet of Things (IoT) has revolutionized our lives and many industries. The simulation results of the proposed solution show that the enhanced DSSS scheme can be a proper waveform in IoT transmission over LEO satellites for both the high-traffic and high-mobility services. We discuss various solutions, such as the preprocessing of Doppler effect and avoidance of packet collision, to enhance the performance of the DSSS and CSS schemes. However, the CSS scheme is more suitable than the DSSS scheme for high-mobility IoT services because of its robustness against the Doppler effect. Simulation results indicate that the DSSS scheme is more suitable than the CSS scheme for high-traffic IoT services because of its robustness against interference among multiple terminals. The performance of both waveforms was measured in terms of the packet error rate, throughput, and packet loss rate, considering the Doppler effect caused by the high speed of LEO satellites and the interference among multiple terminals. To determine a suitable waveform for Internet of Things (IoT) transmission over low-Earth orbit (LEO) satellites, this paper reports the results of a performance comparison between chirp spread spectrum (CSS)-based LoRa and direct sequence spread spectrum (DSSS)-based Ingenu.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |