Home connection on the LTE network: a tempting offer, or a deferred problem?

Home connection on the LTE network: a tempting offer, or a deferred problem? 

Gone are the days when the only way to get online from home was a slow dial-up connection. Today, households can choose from a fairly wide range of connections: copper cables from the former telephone network, optical fibres, and wireless WiFi solutions.

A new option is to connect a household via the LTE network of the mobile operators. The mobile operators promise excellent parameters for their fixed connections over the LTE network: dizzying speeds and high data volumes. But is LTE really an ideal fixed connection?

TIP: Do you like news? Take a look at our article Virtual reality as a phenomenon of our time.

With wires or without?

The most common types of fixed internet connection in the Czech Republic are connections over the telephone line. The technology is based on various xDSL (Digital Subscriber Line) variants. The technology has its advantages, but also its disadvantages. The connection depends on the distance from the exchange or DSLAM, the quality of the copper cables in the ground and the quality of the wiring inside the building. When all these technical conditions come together, xDSL works. But in reality, fast connections are as rare as hen's teeth.

Other technologies fare considerably better: customers within reach of the optical network are the most satisfied, and well-built coaxial cable (HFC) networks have good potential. However, their construction is expensive and, moreover, administratively demanding. Households therefore choose wireless technologies.  And these are very well developed in the Czech Republic, both commercially and technologically. In 2017, mobile operators began offering an alternative to the highly successful WiFi: a fixed connection over the LTE network. These connections are not yet reflected in the statistics of the Czech Telecommunication Office (CTU).

LTE and WiFi. Not only mobile phone owners will certainly be familiar with the term “LTE connection”. The abbreviation LTE stands for “Long Term Evolution” and refers to a high-speed mobile internet connection technology designed as the successor to GSM. The maximum theoretical speed of 4th-generation networks, LTE, is up to 172.8 Mbps for download and 57.6 Mbps for upload at a channel width of 20 MHz. These are very impressive theoretical values that are sure to make an impression. But WiFi networks also make theoretically possible transfers in the hundreds of megabits. So what is the actual theoretical difference between the WiFi and LTE protocols?

LTE and WiFi use the same modulation schemes, the same methods of combining multiple carriers into the used MIMO band, and they even use the same technical terminology. Of course, that does not make them the same: LTE has features that a WiFi network does not inherently need. So the main difference lies in the method of switching between transmission and reception: LTE is full duplex, while WiFi uses the same channel for both transmission and reception. Thanks to this, the 802.11 protocol saves bandwidth, and in an equally wide radio channel it carries almost twice as much data. We could pile up technical definitions and the problems arising from them, but all of them can be solved by proper network planning.

Radio systems are therefore fundamentally similar. At first glance, the fixed LTE offer from mobile operators seems to have no catch. But why is fixed LTE not doing so well in Europe? 

The ideal solution?

LTE networks are not primarily developed and designed for fixed home connections. Admittedly, in principle such use cannot be ruled out, and development strategies for 5th-generation networks do take fixed use into account. But that would also require a fundamental change in the philosophy of planning and building such networks.

The main problem of a mobile network is the impossibility of predicting the data load. Admittedly, mobile operators have enough bandwidth to connect mobile phones to the base station (BTS); some 4G frequencies are not even used.

The stumbling block lies in the capacity of the backhaul network, which connects customers' data and carries it into the optical infrastructure, and further into the data centres where networks are interconnected and thus form the Internet.

We must not forget that all customers of the mobile network use the same access line. Smartphones connected to a cell often make full use of their data connection. If you add customers' calls to that, and on top of that the traffic on newly built fixed home connections, you get technological factors that limit the stability of the connection.

The load on a mobile network simply cannot be predicted. And it is very expensive for mobile operators to dimension the network so that it can serve all connected users. We can logically infer why it is important for mobile operators to limit data packages through a FUP (fair use policy). Believe me, a mobile tariff with no data limit is very addictive, and watching HD video is just the icing on the cake of the possibilities this kind of connection offers. That is why the colleagues from the mobile side only allow fixed LTE connections at base stations with spare capacity. After all, several data-hungry devices can be connected in one household at once. HD internet TV is a greedy bandwidth hog, as are several smartphones belonging to family members, a security camera's video feed, and a YouTube video blaring out the popular screeching of one of the family's teenagers.

The mobile network was not built for that, and the quality of such a connection shows it.

I carried out a calculation according to the CTU methodology for verifying the parameters of fixed networks.

I simulated what happens if you connect households with 100 Mbps plans one by one to a single sector of an LTE network using a 20 MHz bandwidth. Would you dare to guess how many of them could be connected under the valid methodology while the connection still meets MEF 23.1 Tier 1 Medium, the benchmark for a high-quality connection?

A single sector with a backhaul line of 360 Mbps (a 1:1 line without any aggregation) will connect just eight home users.

If an operator connects eight clients on 100 Mbps plans within one BTS coverage area, it will have no capacity left for the other users of the mobile network. And that is not an acceptable scenario, as operators must provide mobile telephony services. The drop in quality will therefore come at the expense of home connections.

Latency: the stumbling block

One of the main reasons why many users consider LTE as a fixed connection is transfer speed. However, that figure is only theoretical and depends on network load, which is quite high because of mobile users. The actual speed a user gets is then in practice much lower, and when the network is heavily loaded, LTE latency rises almost exponentially.

Latency is the time between a request for an action to be carried out and its execution, that is, the time a data unit takes on its way from the point of sending to the destination. Latency is measured with a tool called “ping”, which is available either online or through a terminal on your computer.

On computers running Windows, type cmd.exe into the search box in the Start menu and press Enter. On macOS/OS X computers, open Applications -> Utilities -> Terminal in Finder, or press Cmd + Space and type Terminal into the field. On Linux, you will find Terminal in the Accessories folder inside the Applications directory; in Ubuntu, the keyboard shortcut Ctrl + Alt + T is enough. In the black terminal window, type, for example, “ping www.seznam.cz” (without the quotation marks), and within moments you should see data about the network response of your connection.

A wired Ethernet connection shows, on average, 5–20 ms, similar to a WiFi connection, for example.

On mobile networks (4G, 3G), latency can be hundreds of milliseconds, which is a clearly noticeable value. The MEF 23.1 methodology mentioned above allows 20 ms in one direction, which means 40 ms there and back.

As the number of devices registered on a 4G LTE network increases, latency rises from packet to packet to values above 100 ms.

At such a response time, the connection is already perceived as poor quality, and for example practically unusable for online gaming. Since LTE always gives voice services priority over data, the relevant transmitters are often overloaded, even though voice does not demand much data capacity.

When the communication time slots are loaded with a large number of registered mobile phones, the response time often fluctuates up to hundreds of milliseconds. Precisely this rise in latency up to hundreds of milliseconds, even while transmission capacity is still sufficient, is the typical sign of a fixed connection on a mobile network. It takes no more than an unusual number of people at a village festival on the village green to cause such behaviour.

Connection capacity

When many devices are connected, the network response time rises, but if we add up the data demands of mobile data users connected at the same moment to the same BTS, we will witness a rapid drop in the capacity of home connections on LTE. And modern phones with their HD cameras, online photo backups, Facebook and other conveniences are big megabit guzzlers.

LTE operators defend themselves against complaints that users of this technology are bound to raise by pointing to the wording of their General Terms and Conditions. All three operators that offer plans with tens of Mbps for home connections consider a drop in download speed only as far as 16 kbps grounds for complaint in their T&Cs. That is 0.016 Mbps.  No great guarantee, is it?

Not all wireless is equal

By contrast, a well-designed and well-built wireless network does not have such drawbacks.

At any moment, you know how many customers are connected to an access point. Usually there are very few, typically only a handful of connections per access point. Traffic management based on the customer's plan, and dynamic allocation of resources at the border router, ensure stable, steady and low latencies. Even compared with a purely optical network, the values of a fixed wireless network are not fundamentally different. Wireless time-division duplex elements are used in the last mile to the customer; the remaining elements all the way to the data centre are, with a few exceptions, professional technologies based on microwave communication with latency below 1 ms, connected to the optical backbone infrastructure. The decisive factor is therefore how the occupancy of the network's access point is managed. And on an LTE network, that cannot be predicted.

That is why local operators can afford to guarantee a much higher minimum speed.

Acquisition costs

This is a generally overlooked part of the price of a plan. The wireless device for a fixed LTE connection is usually lent under a 24-month contract for a token price, but its real value lies in the installation cost. When the service ends, the user pays for dismantling, and that is a considerable item of around CZK 2,500. Without a contract, for example for a trial with the option of returning the device, installation and dismantling will cost CZK 5,000. No local operator charges such costs, at least not that I know of. On top of that, you need to add the price of a home WiFi router, which often represents another investment of more than CZK 1,000.

* CZK 499 incl. VAT with a contract, CZK 749 incl. VAT without a contract

** CZK 1,499 basic modem, CZK 3,999 premium modem

*** The actual modem price is CZK 2,301, paid in monthly instalments of CZK 100

**** CZK 399/month plan + CZK 100/month modem instalments

***** CZK 1 with a fixed-term contract, CZK 2,599 with an indefinite-term contract

Playing it safe

When choosing the right internet connection, you need to use common sense and basic arithmetic, and study the terms and conditions thoroughly. At the moment, LTE connections are primarily aimed at owners of smartphones. Mobile devices and voice services will always get priority on this network, and they can load it so heavily that the connection becomes practically unusable for other users.

When choosing the ideal connection for your household, it is best to first check which services are available at your address. Then consider what you will use the internet for. A user who often uploads large content to the web (for example high-resolution photos) will have higher demands on upload quality, while a person who mainly uses the internet for browsing social networks and reading e-mails need not worry about this parameter much. Once you have weighed up all the aspects, you will surely be able to choose the most suitable connection for your household, with all its advantages and disadvantages.

Author: Amaya Tomanová, Jakub Moník

Updated 5 March 2024