With the abundance of wireless technologies available in 2015, connecting devices without wires has never been easier. Choosing the correct technology for your IoT device is one of the most important design decisions to be made.
When selecting a wireless standard to your device, there are a few main considerations that must be made.
• One of the most important considerations is power consumption. Will your device be battery powered or will it be plugged into a wall? Battery powered devices must conserve as much energy as possible to limit how often a user must recharge their device.
• The second consideration is the amount of data that will be communicated between the device and the user’s phone, the cloud, or a central hub. Certain technologies provide much higher throughput than others, so the proper design choice here is critical. For instance, music and video streaming applications will require much higher throughput than a fitness tracker.
• Depending upon the desired distance of transmission and physical location of the devices, frequency and transmission power will be another important design decision. The frequency at which a device communicates will affect the device’s ability to penetrate walls and buildings as well as the overall distance the signal can travel. In general, lower frequencies can penetrate walls and buildings better than higher frequencies.
• Lastly, is the network topology or how the devices connect with one another to provide the user with data or the ability to control their environment. Will there be a central hub all devices talk to or will the devices talk directly to the user’s mobile device or will every device talk to one another in a mesh configuration?
These are all important questions one must consider when developing an IoT device.
Bluetooth is one of the most widely used wireless technologies for many reasons. Bluetooth devices tend to have very low power consumption and with the advent of Bluetooth Low Energy (BLE), devices such as the Tile property tracker  can last for years on a single coin cell battery. Additionally, Bluetooth has the ability to transmit many different forms of data from small bits of sensor data to streaming audio, making it very flexible from a communications throughput perspective. Bluetooth operates at a frequency of 2.4GHz with generally lower transmission power which limits the range to a range of approximately 30ft. Because of the limited distance, devices generally pair directly to a user’s PC or mobile device so it is commonly used in applications such as fitness trackers, smart watches, and Bluetooth enabled speakers where the user only requires a connection while in the vicinity of the device.
Zigbee is another wireless technology that operates at 2.4GHz but at a much higher power, allowing devices to communicate over much larger distances. To increase the distance even further, Zigbee is one of the most popular mesh networks for IoT devices. In a mesh network, each device can talk with nearby devices allow data to “hop” from one device to another until it gets to its intended destination. These types of networks are great for large sensor installations such as energy monitoring implemented by power companies. Power usage is higher than Bluetooth as each “node” must wakeup to listen to data from other “nodes” but because each device does not have to transmit as far, the power consumption is still less than WiFi. However, the programming required to produce a reliable mesh network is much more difficult and requires more stringent testing.
WiFi has been a mainstay of PC and mobile device communications for over a decade now but is just starting to break into the IoT market. WiFi has been used for high throughput wireless connections such as internet browsing and streaming music and video due to its high bandwidth capabilities reaching over 1Gbps with the latest standards. However, high bandwidth comes at the price of high power usage which has kept WiFi technology out of reach of devices with limited batteries. Newer technologies and protocols such as those used in Texas Instrument’s CC3200  allow devices to limit power consumption while maintaining reliable WiFi communications. Additionally, most consumers already have a WiFi access point in their homes that they can connect new devices to without having to purchase additional hardware. This also provides devices with a direct connection to the internet where they can download updates or upload data to the cloud.
ISM Band Devices
The last common wireless technology used for IoT devices are generic ISM band transceivers which is a class of devices that operate using custom protocols in at different frequencies commonly ranging from 100MHz to 1GHz. These devices work well in long range applications or in urban environments where walls and building may be between the device and the end user or central hub. The lower frequencies allow the signal to better penetrate these obstacles. As we have mentioned in previous posts, ISM band devices such as Semtech’s LoRa transceivers can communicate at distances up to 15km . Similarly to Zigbee, the custom nature of the protocols used in these types of devices requires significantly more development and testing time.
Not sure what wireless technology is right for your product? Anuva has extensive experience in many different wireless technologies and can help you choose the right one for you!