RuBee (IEEE 1902.1)
RuBee (IEEE 1902.1) is a protocol that uses Long Wave (LW) magnetic signals to transfer information. The technology is in its final stages of development by the IEEE.[1]. The protocol is similar to WiFi (IEEE 802.11), Zigbee (IEEE 802.15.4) and Bluetooth (IEEE 802.15) which are all radiating transceivers. The new specification, which builds upon the technological breakthroughs realized in HF and UHF RFID technology, will improve on the visibility network protocol known as RuBee.kHz. Visibility networks, such as depicted in Figure 1, are employed to provide the status and location of people or other high-value assets in a user-configured region.
How RuBee works
IEEE P1902.1 RuBee employs inductive communication which means it relies upon magnetic energy — rather than electric energy. This stems from the fact that it operates below 450 kHz which is below the AM radio band. Thus virtually all of the energy radiated by a RuBee base station or a RuBee tag is magnetic (H), rather than electric (E), as is depicted in Figure 2. RFID uses both forms depending on the frequency. Low frequency (LF - usually around 125KHz) and high frequency (HF - usually around 13.56MHz) radio tags use magnetic coupling, whereas UHF and microwave tags use radio in which the electric field is more important. In retail applications in the USA, 900MHz UHF tags predominate, as shown in the figure in which almost all the energy is electric — or as it is commonly termed 'RF'. If strong enough, magnetic waves can pass through almost anything, even rock. That same rock blocks RF after only a few feet. Another important distinction between magnetic E waves and RF is that the strength of an RF signal falls off from a linear wire or a sphere as 1/r whereas the strength of a magnetic wave falls off far faster at the rate of 1/r3. This means that assuming the same input power is applied to a magnetic source and a RF source, the magnetic signal will not travel nearly as far as the RF signal. At first glance this difference in fall-off rate may appear as a negative for a magnetic signal, but as we explain below it turns out to be quite a plus for a RuBee local visibility network. Secondly, magnetic signals are generated far more efficiently at low frequencies than electric fields.