What is the difference between LTE and Wi-Fi?

The key difference between LTE and WiFi is coverage. LTE coverage has been widely expanded in recent years, so there’s likely to be mobile coverage where you need it. Wi-Fi on the other hand, even if it is a public Wi-Fi network will have a limited footprint, when compared to LTE.

Let’s look in more detail how LTE and WiFi compare.

Introduction

Smartphones have allowed us to do things that once needed laptops or a handheld, truly portable devices. Being “always-on” and with better battery life smartphones have become the most widespread internet access device. Smartphones have also driven the growth in the use of both LTE (4G) and WiFi to connect to the internet – but what is the difference? Which is best for my IoT or data solution ? Let’s start with some basic information on both.

What is WiFi?

WiFi is a wireless networking protocol that allows data to be passed without the need for wires. Defined by meeting the 802.11 IEEE standards, over time the speed and coverage Wi-Fi can provide has increased significantly. WiFi is a trademark of The Wi-Fi Alliance , a body that drives global adoption and is made up of device and service providers.

How Does WiFi Work?

WiFi depends on a critical central hub, or “access point” that propagates the WiFi network. This hub controls which WiFi devices can connect to the WiFi network it creates.  It also brokers connection between devices on the WiFi network and controls the transfer of data between them. Many WiFi hubs are also a part of a broadband router that allows a WiFi device to reach the internet, and transfer data.

Extending a WiFi network’s coverage area can be done by adding further hubs. These can be linked together using either wired /ethernet connections, or WiFi. The capabilities of WiFi are constantly evolving, here's a good summary of what WiFi can do and how that has developed over time. .

What is LTE?

LTE (Long Term Evolution) is often described by the generic term 4G. Essentially, they are interchangeable terms describing the public mobile networking technology that succeeded 3G. LTE provides far more bandwidth than was available for 3G. What this means is that larger volume data transfers can be done, and those possible under 3G run a lot faster. Built on work done in 3GPP, the mobile networking standards body, LTE is a significant step forward. Here's much more detail on LTE capabilities.

How Does LTE Work?

A mobile operator's phone masts generate the wireless network and allow LTE enabled devices to connect to it. The ability to connect depends on a SIM card on the device that initially “shakes hands” with the network and validates that it is allowed to connect.

Once connected, LTE provides the device with the ability to wirelessly connect to the internet. Unlike Wi-Fi, it does not allow direct data connectivity between devices connected to the same network. That has to be achieved via the internet. In that respect it breaks the conventions of a phone call on the same network, where direct calls between devices are the norm.

What are the differences between LTE and WiFi?

Technology

LTE has a major benefit in that you do not need to worry about managing the network. All you will need is your IoT device and a SIM. The mobile operator owns and manages the physical network needed to provide you with the connection to your device.

Unless you are using a public Wi-Fi network you will need to build and operate the network yourself. If you already have the network for other reasons that may be fine. However, the cost and time of using your own Wi-Fi network needs to be factored into your decision making.

Security

The security of both your data and the devices you use should be a major concern when deploying your IoT solution. The security built into LTE networks, from user authentication to encryption of all traffic, is considered significant. It is constantly being evaluated and updated by cybersecurity experts. It should be remembered that to some extent the operators’ reputation depends on it.

By contrast, with WiFi, the security is outsourced to the user. There are many popular tools/protocols to deliver security on WiFi networks. However, they depend on the user to implement and manage them to deliver the promised benefits. You can read more about the risks and issues associated with WiFi networking (private and public). 

Unless you are prepared to spend time setting up and managing the security you need to manage your data and devices LTE is a clear winner in this area.

Coverage

WiFi will have a limited footprint, even if it is a public WiFi network when compared to LTE. The mobile operators have had a major drive to extend coverage in recent years to meet smartphone user demand. This means it is highly likely mobile coverage will be available where you need it. In addition, if your solution will be mobile, tracking a delivery vehicle, the breadth of coverage a LTE network offers will be key and so probably the best choice.

WiFi may well be suitable for a static solution, for example tracking temperature in a storeroom. If the storeroom is on-site, within the same WiFi network footprint as you, then it will be a good option.

Where the storeroom is at a remote location the number of sensors ay well determine the decision, and whether there is a broadband connection and existing WiFi. Where your IoT solution is static, in a remote location with no existing network connections, LTE could still be the best solution.

Bandwidth

Wi-Fi networks can offer data speeds from 11 Mbps to 1Gbps, with the new Wi-Fi 6 offering up to 10 Gbps. LTE networks can now offer up to 1Gbps so delivering more bandwidth or speed than nearly every IoT solution will need. That means that for most IoT solutions the two technologies both provide more than enough bandwidth.

LTE and WiFi in an ever changing world

Mobile Operators are now focusing on LTE as the replacement for 2G services that they are now retiring at an increasing rate. Since this article was first written 2 of the 4 operators in the UK have announced they will be shutting their 2G networks down in 2025. This allows them to re-use the spectrum to provide much needed capacity for LTE services. LTE network architecture is also seen as the building block for the future of mobile as it was designed to be fully multimedia.

WiFi is also evolving to provide higher throughput and better security management. Next generation hubs are becoming widely available and the increased management capability means the gap between LTE and WiFi is closing fast. This means we are heading towards an environment where LTE and WiFi can work together seamlessly to provide the user with continuous connectivity removing any fear of missing out on that critical social media posting.

A note about the Author: David Steel BSc delivered an innovative free public WiFi network for Cardiff City Council covering the city centre and The Bay. He also pioneered Small Cells for LTE working with all UK Mobile Operators.

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