Bluetooth Low Energy was originally aimed at wearable technology, not the broad IoT market. But in early 2014, CSR, a semiconductor maker, announced a mesh network for Bluetooth, meaning it could now connect to thousands of things.
Devices in a mesh network connect directly with one another, and pass signals like runners in a relay race. It is the opposite of a centralized network. The transmission range of an IoT device on a mesh network is anywhere from 30 feet to more than 300 feet.
Some IoT devices will get power from electrical systems, but many, such as door locks and standalone sensors, will use batteries. These devices send and receive small amounts of information intermittently or periodically. Consequently, the battery life of an IoT device can range from 1.5 years to a decade, if the battery lasts that long. One IoT maker, Insteon, uses both radio and powerline communication, which can send data over existing electrical wiring as well as via a radio, which it says will offer an increased measure of reliability.
An IoT device will have a radio that can send and receive wireless communications. IoT wireless protocols are designed to accomplish some basic services: Operate on low power, use low bandwidth and work on a mesh network. Some work on the 2.4 GHz band, which is also used by Wi-Fi and Bluetooth, and the sub-GHz range. The sub-GHz frequencies, including 868 and 915 MHz bands, may have the advantage of less interference.