Researchers at Pompeii Fabra University and other centers have developed efficient and low-complexity algorithms that have made the Internet of Things via satellites increasingly popular. They achieved this goal because of the random access scheme.
The so-called Internet of Things (IoT) has been continuously evolving for several years. The possibility that machines (nodes) can communicate with each other opens the door to applications that are expected to have a profound impact on our lives. These include smart agriculture, home automation, and vehicle-to-vehicle communication.
One of the basic elements of the Internet of Things is wireless communication between machines, called machine-to-machine (M2M) communication. Unlike mobile networks such as 4G or WIFi networks, a large part of M2M communication is characterized by very low transmission speed, very small data packets, and a large number of devices. These characteristics posed huge challenges in the coordination of telecommunication networks.
Recent research has proposed efficient and low-complexity algorithms, thanks to the implementation of advanced satellite random access schemes, making satellite Internet of Things more and more accessible.It is in International Satellite Communications and Web Magazine, One of the authors is Giuseppe Cocco, Researcher of the Department of Information and Communication Technology (DTIC(UPF) and German Aerospace Center (DLR) researchers) and European Space Agency researchers.
Suppose the crop has a humidity sensor connected to the satellite, which only sends information when the humidity is below a certain threshold. It may be that the sensor has not sent any information for a long time, and when it decides to send information, the amount of data is very small (only a few bits). In this case, the amount of control data required to establish a connection with the satellite network may be greater than the amount of useful data (payload) transmitted by the sensor.
Although using a single sensor does not seem to be a problem, in a satellite network, the number of sensors connected to the same satellite may be very large. Although each sensor transmits a small amount of data very sporadically, the total traffic can be very large. On the other hand, deleting or reducing the control information in the M2M traffic will mean that the signals from different sensors may interfere with each other, which may result in the loss of the sent information, and even crashes in the case of heavy traffic. The internet.
In this case, it can be understood how the control information in M2M traffic becomes a considerable but indispensable resource expenditure to avoid interference, which may result in the need to use larger bandwidth, larger, more expensive satellites or more. The large number of satellites, the cost of M2M communication and the negative impact on the development of the Internet of Things.
In order to solve this problem, in recent years, people have designed a new advanced random multiple access system (Random multiple access), which can greatly limit the control information without compromising network performance. Such systems work counterintuitively, that is, instead of trying to avoid interference, they increase interference so that each node can transmit multiple copies of the same message without knowing whether others are transmitting at the same time.
Cocco explained: “The trick is that the receiver uses the above interference to clean up the received signal by extracting useful information from the received signal.” “To understand how these systems work, you can consider how to eat artichoke: Every time the leaf is removed, most of it is eaten, but the leaves below are also released, so the co-author of the article added that at least one new worksheet can be deleted each time.
Several articles in international scientific journals have confirmed that random multiple access based on the transmission of multiple copies of each message is very promising. In any case, these works use simplifications (which must be able to simplify the work of equations and simulations), which do not allow the performance of these systems to be evaluated in a real environment.
“Our contribution is not just these simplifications. We have studied the impact of various elements in the actual system on the entire system (for example, the defects of the typical low-cost electronic devices in many IoT nodes), and we have developed algorithms to We can strengthen the system to address these problems. By doing so, we have invested special energy to develop algorithms that are both efficient and low-complexity, so that the satellite Internet of Things becomes more and more efficient, and everyone can use it.