Random phase multiple access

Random phase multiple access (RPMA) is the trade name given to a low-power wide-area channel access method product being sold by Ingenu, formerly On-Ramp Wireless. It is meant to be used for machine-to-machine (M2M) communication on the Internet of Things (IoT). RPMA is a communication system employing direct-sequence spread spectrum (DSSS) with multiple access. RPMA reportedly employs transmit power control and receiver sensitivity of (-142dBm) with a total 172 dB link budget. RPMA self modulates to find clear signal both on the network and device level. It is also optimized for coverage and battery efficiency, as opposed to cellular which is designed for high throughput but requires a lot of power. To save battery life, it has a connection protocol in which access points ping the device, check the device status, receive any data, then close the connection. Ingenu estimates that the majority of M2M and IoT connections need this kind of low data throughput and high battery life connectivity.

Coverage

RPMA is currently used in dozens of private networks worldwide. The 2.4 GHz spectrum is available worldwide and is cost-free to use. RPMA access points may cover up to 300 square miles. It would take 30 cellular towers to cover the same area. Ingenu, who owns RPMA, reportedly has some access points covering as many as 450 square miles each.

RPMA's uplink is 624 kbit/s and downlink is 156 kbit/s, which is about 10 times the speed of dialup internet. When moving, RPMA's speeds drop, as is typical for wireless connections, to 2kbit/s.