LOW POWERED, WIDE AREA NETWORKS (LPWAN) SATISFY NETWORK NEEDS FOR IOMT
There are several technologies available to build a network for Internet of Things (IoT). With different competing alternatives and as of yet no mandated standards to adhere to, there are four key parameters to consider: range, power consumption, data rate and penetration. Basic physics won’t allow you to maximize performance in all of them at the same time and the relationship between the parameters makes it impossible to create long-range solutions while allowing high data rates with low power consumption. Following is a short reasoning showing the high-level requirements of technology for IoMT.
A majority of future connected devices will be moving. The best solution for IoT would, therefore, be a solution which best satisfies the needs of connected moving things. So what are the requirements in terms of range, power consumption, data rate and penetration for the IoMT?
RANGE, POWER CONSUMPTION, DATA RATE AND PENETRATION
Firstly, let us look at the range. Moving objects will often cover larger areas. Short range solutions like Bluetooth and WiFi only cover meters and would not be optimal as moving objects will move around in areas like large buildings, production sites or cities. What if a device gets stolen and leaves the tightly covered area? What if an important piece of equipment is placed outside a building and loses contact with the network? Long range solutions would definitely be preferred over short range solutions.
Secondly, we consider power consumption. Most moving objects will not be able to utilize external power sources. In addition, moving objects will obviously not remain in the same place. It’s inconvenient to change or recharge batteries and devices losing connection while on the move may also disappear. This makes battery life of the device important, which in turn means power consumption must be low. Technologies like 3G and LTE will satisfy the range requirements and offer high data rates and might at a first glance be suitable. These solutions are however disqualified due to the high power consumption relating to range and data rates. NB-IoT is supposed to partly solve this issue but has not yet been demonstrated in any widespread deployments.
Thirdly we look at the bit rate. As long range and low power consumption is required, bitrates can’t be high and the question is if a “low” bit rate is good enough for IoMT. In fact, a typical IoT application won’t require high bit rate or large data payloads. Smart connected devices are also inactive most of the time and smart data management can keep the bit rate requirement low. 3G, LTE, and the upcoming 5G will allow for high-quality video streaming, but that is certainly not necessary for IoMT.
Finally, penetration is considered. The range is important but not particularly useful if penetration inadequate. Connected devices will be moving around in complex environments, full of obstacles and without adequate penetration signals will bounce, reflect or get blocked. As free line-of-sight is rare in most applications, penetration of structures is clearly important too for a functional network with real-world applications.
Table 1: Requirements of an IoMT technology
A Low Powered, Wide Area Network (LPWAN) offers long-range communication, low power consumption, and low bit rate. The range can be measured in hundreds of meters without claiming high power consumption. As data rate is not as important as range, battery life and cost, LPWAN technologies are optimal for IoT in general and IoMT in particular. At sub-GHz frequencies, the signal has greater penetration abilities.
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