There’s been a lot of talk about what will be the most dominant wireless access technology to connect the Internet of Things (IoT) recently.

A research report by Goldman Sachs claimed that unlicensed spectrum and cheaper transfer rates would make Wi-Fi the leading player.

"Just like wired access (copper and fiber) laid the foundation for the fixed Internet, and cellular access (3G and 4G) enabled the mobile Internet, we expect Wi-Fi to be the enabler of the IoT," analyst Simona Jankowski said. .

On the other hand, Vodafone’s latest M2M Adoption Barometer found that 84% of M2M adopters said that 4G was "very important" or "quite important" to their project.

The UK-based operator said: "We predict that 4G will make new kinds of application practical and cost-effective, including video-based security, in-vehicle information services, assisted living and mHealth solutions, and much more."

But this research conflicts with what Cambridge-based networking startup Neul told CBR back in May – that expensive, energy inefficient and poor penetration will stop 4G cellular technologies playing a major role in the IoT.

"They [LTE 4G networks] were really built for voice or broadband and with recharging phones in mind, which doesn’t really fit for the IoT because a lot of these sensors that need to be connected need to last for years from a battery," Ben Peters, Neul’s head of products said.

So what is the answer? Jim Tully, distinguished analyst for IoT at Gartner, told CBR many forms of communication will be required.

"Most examples of ‘Things’ will not require high bandwidth or high speed data communication…Thermostats, toothbrushes, light bulbs, electric door locks, movement sensors, toys, anti-theft tags, smart weighing scales, and so on can operate with limited short range wireless connectivity using Bluetooth or ZigBee," he explained.

"WiFi will normally be needed for higher bandwidth IoT applications such as set top boxes and security cameras that are streaming a lot of data. Some IoT devices such as wearable fitness monitors will also use Bluetooth but they will work in conjunction with a smartphone.

"Outdoor devices in particular will make a lot of use of cellular – in parking meters, vending machines, smart trash cans, and so on – not to mention cars."