A small percentage of the market can tolerate devices that need mains power but many, such as remote sensors, cannot for either technical of commercial feasibility reasons: A sensor in a refuse bin for example will typically be off grid. Sensors embedded in a car parking space to tell you whether the space is vacant or occupied could, in principle, be mains powered. However, the cost of excavating every space in every car park or on street parking zone to provide mains power is both impractical and financially prohibitive.
GPRS, 3G and LTE based technologies, no matter how much power optimisation is designed in, can never compete with LPWAN technologies and ultra efficient protocols designed explicitly for IoT/M2M use cases on battery life. At best a typical telephony based cellular technology can operate for a number of weeks but the terminals must operate in the field for years to become commercially feasible.
IoT/M2M terminal devices need to be a simple as possible, with much of their functionality handed off to the network in order to minimise power consumption.
Weightless has been designed from the outset to provide 10 year battery life from an AA form factor battery. This is achieved through a number of techniques:
Weightless terminals are able to function with a very low transmit power. Both Weightless-N and Weightless-W signals in ISM and white space spectrums achieve long range at low signal power.
Weightless terminals have very long sleep periods. The device will wake only every 15 minutes, synchronise its clock and listen briefly – for about 100ms - to determine whether there are any changes to the system or any messages that need to be acted upon. If not, it will return to sleep again for another 15 minutes. Weightless devices will therefore only be awake for minute amounts of time.
Weightless has been designed to be very simple to implement from the terminal side. All of the complexity is retained in the network, and so the terminal is not required to carry out any complex calculations. This means a Weightless terminal has no need for powerful, quad-core processors. Even when the terminal is awake its lightweight processors mean that power consumption is very low.
Long battery life is critical for the large majority of M2M systems and applications and the Weightless system delivers this characteristic. ‘Fit & Forget’ Weightless modules are now possible in the field.
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