You’ve probably read various articles about the ‘protocol wars’ in the wireless world especially as it relates to the Internet of Things (IoT). Some of the more creative ones read like a synopsis of the latest “Mad Max” movie. But dig a little deeper, and these so-called wars really amount to shuffling for attention among peers all jockeying for starring roles in the movie.
Unlike wired protocols, wireless protocols need to address a number of different needs: in-medium noise, interference, constant changes to the characteristics of the medium itself, the specialized needs of low power (battery operation), high throughput, reliability, and range. The result is that wireless communications requires various methods, frequencies, and protocols. Sprinkle some competition among wireless providers, and you get muddying of the water rather than clarity as they each try to build market share.
To help you keep score on the wireless front, here’s a synopsis of some of the most important protocols and specifications and what each does best:
Wi-Fi : If there were a ‘Protocol Wars’ sci-fi movie, Wi-Fi would be the big box-office star. It’s still the best, making direct connections to the Internet, and it’s widely supported in home broadband installations. People don’t doubt their Wi-Fi. They expect it to be there and to work no matter where they are. Wi-Fi is also moving into lower-power implementations with new technology advances. 2.4GHz Wi-Fi has worldwide support, making it the easiest-to-find wireless protocol. 5GHz Wi-Fi has better throughput, but its range comes at increased power or processing (beamforming). The 5GHz spectrum is not available worldwide for Wi-Fi.
Bluetooth: Bluetooth might not be the star of the movie, but it has a strong supporting role. Also running on 2.4GHz, this protocol reduces power consumption but also reduces bandwidth. BT does not have direct Internet access, but it’s popular because it is supported by all smartphone platforms. This protocol is good for direct control of up to eight devices from a smartphone. The latest specification, BT4.0, incorporates a low-power version that is suitable for low-power battery operated devices, but not for devices that require constant two-way communication. This BTLE (low power) is ideal for devices such as event sensors that remain ‘off’ for the majority of their life, waking up only to notify of an infrequent event. BT has matured to the point where users expect it to just work.
802.15.4, aka ZigBee: Another supporting role player, ZigBee is a mainstay for lower-power networks, particularly for installations that require many nodes. Unlike Wi-Fi, ZigBee is not affected by limited node count per local network. Compared to Wi-Fi, it has higher range but lower bandwidth (typically 250kbps). It can increase range with installed nodes, but the expanded range comes at the cost of reduced shared throughput. Also, this protocol suffers from trying to do too much and does not enjoy the compatibility expected from Wi-Fi. It also lacks Internet connectivity. ZigBee is used primarily in the worldwide unlicensed (ISM) 2.4GHz spectrum, but it can also be used in sub-GHz frequencies.
802.15.4, aka Jennet, MiWi, WirelessHART, ISA 100.11a: Think of these protocols as having minor roles in the movie, at least for now. They are alternative network and application stack solutions to ZigBee that also run on the 802.15.4 MAC/PHY. They generally fall into a proprietary class of stacks running on the 2.4GHz 802.15.4 protocol, able to provide improved compatibility and implementation efficiency because they are proprietary. They provide no Internet connectivity.
Thread: This is a specification, still under development, for an IPv6 protocol that will run on top of 802.15.4. Thread will have the benefits of ZigBee and attempts to address some of its shortcomings, including compatibility.
Sub-GHz: This is mostly a proprietary class of implementations running on frequencies below 1GHz. Different frequencies are used for China, Europe, USA, and Australia. This class of protocols will have the best range, the lowest power consumption, and the lowest bandwidth. It’s ideally suited for battery-operated devices, but it provides no Internet connectivity.
Zwave: A protocol similar in application to ZigBee and often compared to it but runs only at sub-GHz frequencies. Zwave is a single hardware-sourced solution from Sigma Designs, although Sigma Design licenses the transceiver to a second source, Mitsumi. The protocol is published as an ITU standard, but the controlled hardware transceiver is primarily responsible for the improved compatibility compared to ZigBee. It has several transceiver frequency implementations for different countries, based on frequency allowance. It has lower bandwidth than ZigBee, but it’s capable of longer range at the same power levels. It provides no Internet connectivity.
Note: Non-Wi-Fi protocols require a gateway to bridge to an IP-accessible network (either Wi-Fi, Ethernet, or cellular) for Internet or Internet of Things (IoT) operation.
As you can see, there are plenty of protocols, but each has a purpose—or at least a carved-out area to address. You will also see many proprietary radios, protocols, and alliances that are trying to address some very specific need for power, bandwidth, range or ease of use for a specific industry.
There are two bad guys in this movie. The first is marketing a protocol as capable of doing all and ‘winning’ over others. The second is engineering a protocol to do a function that is outside its area of strength, and in the process reducing its compatibility or primary strength.
‘Wars’ or no, the protocol movie has plenty of interesting characters to watch. At Ayla, we keep close tabs on the players, major and minor, and make sure that our IoT platform incorporates the important protocols and standards, including new ones that might emerge in the future. That way, if you’re a manufacturer of connected devices, you can sit back and enjoy the show. Just don’t get disappointed if there isn’t as much drama as some of the wireless providers would like you to anticipate.