RPMA a Rising Star...
Regardless of the application type, every IoT solution relies on some network or protocol for connectivity.
With the overwhelming amount of connectivity options available, it’s essential that each is understood so the best business decisions can be made. In this article, we will explore RPMA, a rising star in the LPWAN space.
Ingenu, a wireless IoT startup, designed a public network called the Machine Network that utilizes Random Phase Multiple Access (RPMA), the company’s proprietary LPWAN technology. The main benefits of RPMA are related to coverage and capacity.
Coverage is what makes it possible to deploy a network. The number of base stations needed to encompass an area directly affects the cost of the network. Coverage also determines how reliable the network is as well as impacts battery life. RPMA is built with a physical layer that uses Direct Sequence Spread Spectrum (DSSS) technology. DSSS scrambles and spreads signals in a way that is designed to make the message look random. RPMA spreads the signal even more in order to enable increased latency and make increased use of the processing gain, the increase in link budget or the total gains and losses from the transmitter. The increased processing gain allows for the depth of coverage RPMA provides.
The capacity enabled by this technology is derived from DSSS as well. The technology allows RPMA to handle more noise and interference than other LPWAN technologies. RPMA can even detect signals when they are 2000 times quieter than the noise itself. This gives RPMA the ability to simultaneously send and detect many signals without impairing each other, and thus puts the Multiple Access (MA) in RPMA. The multiple access design gives RPMA its high capacity and its scalability. It also means that the technology can operate alongside WiFi networks even if they were to share the same frequency.
Another key aspect of RPMA is its use of precise transmit power control to keep the signal powerful enough to pass through any interference while minimizing the number of base stations needed. The technology also takes advantage of Forward Error Correction (FEC), a technique to control errors in transmissions over noisy communication channels. FEC controls errors by using convolutional codes and interleaving to protect against sudden interference while giving 100 percent message acknowledgment. This means that messages can be sent using lower power and makes sure the messages don’t have to be sent multiple times, which helps maintain the high capacity and improves battery life.
One issue to consider with regards to RPMA is that the sensors used to support the technology are very expensive. However, it’s up to you to decide if the benefits of RPMA make the technology worth the cost.