RuBee (IEEE standard 1902.1) is a two way active wireless protocol designed for harsh environment and high security asset visibility applications. RuBee utilizes longwave signals to send and receive short (128 byte) data packets in a local regional network. The protocol is similar to the IEEE 802 protocols in that RuBee is networked by using on-demand, peer-to-peer, and active radiating transceivers. RuBee is different in that it uses a low frequency (131 kHz) carrier. One result is that RuBee is slow (1,200 baud) compared to other packet based network data standards (WiFi). 131 kHz as an operating frequency provides RuBee with the advantages of ultra low power consumption (battery life measured in many years), and normal operation near steel and/or water. These features make it easy to deploy sensors, controls, or even actuators and indicators.
1902.1 is the "physical layer" work group with 17 corporate members. The work group was formed in late 2006. The final specification was issued as an IEEE standard in March 2009. The standard includes such things as packet encoding and addressing specifications. The protocol has already been in commercial use by several companies, in asset visibility systems and networks (see www.rubee.com). However, IEEE 1902.1 will be used in many sensor network applications, requiring this physical layer standard in order to establish interoperability between manufacturers. A second standard has been drafted 1902.2 for higher level data functions required in Visibility networks. Visibility networks provide the real-time status, pedigree and location of people, livestock, medical supplies or other high-value assets within a local network. The second standard will address the data-link layers based on existing uses of the RuBee protocol. This standard, which will be essential for the widespread use of RuBee in visibility application's, will support interoperability of RuBee tags, RuBee chips, RuBee network routers and other RuBee equipment at the data-link layer.
RuBee is bidirectional, on-demand, and peer-to-peer. It can operate at other frequencies (e.g. 450 kHz) but 131 kHz is optimal. RuBee tags can have sensors (temperature, humidity, jog), optional displays and may have a full 4 bit microprocessor with static memory. The RuBee protocol uses an IP Address (Internet Protocol Address). A tag may hold data in its own memory (instead or in addition to having data stored on a server). Some tags have as much as 5 kB of memory. RuBee functions successfully in harsh environments, with networks of many thousands of tags, and has a range of 1 to 30 m (3 to 100 ft) depending on the antenna configuration. By 'harsh environment' we mean situations in which one or both ends of the communication is near steel or water. RuBee radio tags function in environments where other radio tags and RFID may have problems. RuBee networks are in use in many visibility applications, including: exit entry detection in high security government facilities, weapons and small arms in high security armories, mission critical specialized tools, smart shelves and racks for high-value assets; smart entry/exit portals.
The major disadvantage RuBee has over other protocols is speed and packet size. The RuBee protocol is limited to 1,200 baud in existing applications. The IEEE 1902.1 specifies 1,200 baud. The protocol could go to 9,600 baud with some loss of range. However, most visibility applications work well at 1,200 baud. Packet size is limited tens to hundreds of bytes. RuBee's design forgoes high bandwidth, high speed communication because most visibility applications do not require them.
The use of LW magnetic energy brings about a number of advantages:
This protocol is similar at the physical level to NFC (13.56 MHz carrier, basically an air-core transformer pair) and also Qi's inductive energy transfer (100 kHz-300 kHz carrier). Both modulate the receiver's coil load to communicate to the sender. Some NFC tags can support simple processors and a handful of storage like this protocol. NFC also shares the physical security properties of "magnetic" communications like RuBee, however NFC signals can be detected miles from the source. RuBee signals are detectable at a maximum distance of 20 metres (66 ft) from the source.