4G LTE and 5G internet: Why is my mobile data so slow?

4G and 5G mobile networks can offer high-speed mobile data services and can already deliver download and upload speeds previously only possible with fibre broadband internet. If you are struggling with your mobile data speed, the chances are that the issue is either with your network or your device.

Your 4G or 5G mobile data may be slow if you are not using the right mobile operator, an up-to-date phone or the best SIM plan. Network issues like poor coverage, busy network, throttling, and tariffs with speed-cap can limit your speed. Your data speed will also be slow if your device is outdated.

Your mobile data may be slow due to your network or device

While there can be a myriad of reasons why your mobile data speeds may be slow, the issues that slow you down can be either phone-related or network-related. When it comes to mobile data, the latest cellular technologies on an up-to-date device generally deliver the best experience.

So, for example, if you have a choice between using LTE or LTE-Advanced Pro on your phone, the highest bit rates and lowest latencies are more likely to be ensured by the latter. However, if your mobile phone does not support the advanced antenna and channel technologies that LTE Advanced Pro uses, your phone will not be able to access it even if your mobile operator offers LTE Advanced Pro in your area.

Cellular technologies like 4G LTE (Long Term Evolution) and 5G NR (New Radio) use advanced antenna technologies like MIMO (Multiple Input Multiple Output) and Massive MIMO. However, these technologies require new hardware on both the network and the device sides to improve your signal quality and bit rates.

4G and 5G networks also use carrier aggregation to increase your channel bandwidth and advanced modulation techniques, including QAM (Quadrature Amplitude Modulation), to deliver higher bit rates on your device by efficiently utilising the available bandwidth.

In 4G LTE, when there is a new enhancement such as LTE Advanced Pro, the existing configuration for techniques like MIMO, QAM and carrier aggregation need to be increased to improve the achievable data rates. However, this improvement only works if the mobile network and device support the new configuration.

For instance, the original LTE network supports a MIMO configuration of 4 x 4 in downlink which means whenever you download; the network sends four layers of transmission toward your phone. Your phone can use up to four communication layers to receive the signal. The LTE Advanced enhancement uses a higher configuration of 8 x 8, but if your phone does not support it, your experience will be based on the 4 x 4 configuration.

Similarly, LTE Advanced networks use a carrier aggregation of up to five (5) channels allowing you to get a maximum bandwidth of 100 MHz (5 x 20 MHz). The LTE Advanced Pro enhancement supports carrier aggregation of thirty-two (32) channels that can offer a maximum bandwidth of 640 MHz (32 x 20 MHz).

If your cell phone or mobile broadband router is not compatible with the latest network configuration, your mobile device will operate as normal, but your data rates will be based on the older network configuration, which can limit your speed. So, for example, if you have an LTE phone that you purchased before LTE-Advanced was introduced, your phone may not support the required network configuration to take advantage of LTE Advanced.

The basic rule for avoiding mobile data speed issues is to choose your mobile network operator and mobile device carefully. Then, depending on your data needs, you can choose the cellular technology (e.g. 4G or 5G) that is good enough for your data needs and a device that supports the technology.

How to know if your mobile data speed is below average?

Mobile data is no longer limited to cell phones only because it is now also a viable option as a broadband service in many countries. Your expectations of the mobile data speed will depend on what you want to use mobile data for.

For example, if you use 4G on your cell phone, your mobile data need may be limited to one person (you). However, your data needs and expectations will be much higher if you plan to use a 4G LTE mobile broadband router for the entire household.

The table below shows the average mobile data speeds from the different cellular technologies used by 2G, 3G, 4G and 5G mobile data services. The middle column in the table shows the symbols you will see when served by GSM (2G), UMTS (3G), LTE (4G) and 5G technologies and their enhancements.

Network Generation & TechnologySymbols you can expect to see on the phoneAverage mobile data speed
5G – NR5G, NR150-200 Mbps
4G – LTE Advanced4G +, LTE+, LTE-A50-80 Mbps
4G – LTE4G, LTE15-20 Mbps
3G – UMTS – HSPA+H+5-8 Mbps
3G – UMTS – HSPAH<5 Mbps
3G – UMTS3G384 kbps
2G – GSM – EDGEE130-200 kbps

—Table showing the average mobile data speeds for 2G, 3G, 4G and 5G cellular technologies and their symbols —

Generally, you can expect lower mobile data speeds from 2G and 3G networks and higher data speeds from 4G and 5G networks. EDGE, UMTS and HSPA enable average download speeds below 10 Mbps. 4G LTE and LTE-Advanced networks can help you achieve average speeds of 50-80 Mbps. 5G is the latest technology and can already offer average speeds of over 100 Mbps.

The screenshots below show what to expect on your mobile phone screens when you are served by 2G and 3G technologies like EDGE (Enhanced Data for Global Evolution), 3G UMTS (Universal Mobile Telecommunication Service), and HSPA+ (High-Speed Packet Access Evolution). As you may note, the download and upload speeds are not high when using these 2G and 3G technologies.

Screenshots showing the symbols and speeds for 2G EDGE (E), 3G UMTS and 3G UMTS HSPA+ (H+)
— Screenshots showing the symbols and speeds for 2G EDGE (E), 3G UMTS and 3G UMTS HSPA+ (H+) —

As shown in the screenshots below, 5G NR networks can deliver an average download speed of between 150 Mbps and 200 Mbps which is good enough for most use cases like HD video streaming and gaming etc.

4G LTE networks with LTE Advanced and LTE Advanced Pro can enable average download speeds of 50 to 80+ Mbps. If you need more details on the mobile data speeds for 2G, 3G, 4G and 5G networks, please look at my dedicated post on average 2G, 3G, 4G and 5G data speeds.

Screenshots showing the symbols and speeds for 4G LTE and 5G NR networks
— Screenshots showing the symbols and speeds for 4G LTE and 5G NR networks —
— A video that explains why your mobile data may be slow —

How to find out the root cause of your slow mobile data?

When you have identified that your mobile data speed is slow, you can do a few checks to get to the bottom. If the issue is with your device (cell phone), you can use some “home remedies” at the bottom of this post to see whether the problem can be fixed or if you need a new device. On the other hand, if the issue is with your mobile network, then your only option is to speak to your network operator to address the issue.

1 – Check if your phone is on the right network technology

If you have a mobile phone or broadband router, you want it to be mostly connected to the latest cellular technology it supports. For example, if you have a 5G compatible mobile phone, you want it to mostly show the 5G network symbol instead of the 4G or LTE symbol. That way, you are more likely to get higher mobile data speeds on your device.

Similarly, if you have a phone that does not support 5G but is limited to 4G LTE, you want to see the 4G, 4G+, LTE or LTE+ symbols most of the time on your phone screen instead of the 3G, HSPA+ or HSPA symbols. However, the mobile data speed of 5G or 4G also depends on your mobile operator’s network quality.

— On a 5G compatible mobile phone or device, you want to see the 5G network symbol most of the time —

2 – Check your network operator’s coverage in your area

If you find yourself in a situation where your mobile phone is not connected to the latest cellular technology most of the time, then you may want to check the network coverage map for your mobile operator. The best way to do that is by checking the coverage map directly on your service provider’s website, which is usually the most up-to-date. Some third-party websites and apps also provide this service.

For example, have a look at Vodafone UK’s network coverage page on their website to get a feel for what information a coverage map provides. When you enter your geographical location into the coverage map, it should display how the 2G, 3G, 4G and 5G network coverage in your area looks like. Ideally, you want to see good indoor and outdoor coverage in your area for your desired network technology.

3 – Compare your mobile data speed with the average speeds

If your 5G or 4G phone is connected to the latest network technology most of the time, but you still experience slow mobile data, then you need to test your mobile data speeds. As shown in the table above, with 5G, you can expect average download speeds of 150 Mbps to 200 Mbps.

If you have a 5G phone and your speeds are not in that region, you may have a network quality issue. Similarly, if you have a 4G LTE phone that is not too old, you can expect it to deliver average download speeds of 50 – 80 Mbps when connected to the LTE Advanced network.

Some Android phones show LTE Advanced and LTE Advanced Pro as 4G+ or LTE+. However, not all Android phones display these symbols. For example, the Android phone in the picture above (Google Pixel 5) shows the 4G symbol even when the phone is connected to LTE Advanced. iPhones also do not show the 4G+ or LTE+ symbols and just show 4G to cover both.

4 – Find out if your mobile tariff has any limits or caps

Sometimes mobile operators do not offer their best mobile data speeds on all tariffs. For example, some mobile operators in the UK do not allow you to connect to their 5G network on a pay-as-you-go SIM (prepaid). They also often have some pay monthly (postpaid) tariffs with unlimited data but with a speed cap.

For example, a mobile operator or cellular service provider may decide to offer a 5G pay monthly tariff with unlimited minutes, texts and data but with a speed cap of, say, 20 Mbps. The speed cap allows a mobile operator to restrict the mobile data rates for the customer to control the overall data consumption.

While technically, the speed cap requires a mobile operator to “throttle” your data speed, throttling is a separate concept in which a mobile operator puts a temporary or long-term speed limit on a tariff in specific situations. For example, a mobile operator may decide to apply throttling to put a sudden speed limit on a customer’s mobile data if the customer is not adhering to the Fair Use Policy.

I have written a dedicated post on throttling to explain what throttling means for 3G, 4G and 5G networks. Have a look at that post if you want to learn more.

5 – Determine if your mobile phone is up to date

Last but not least, you want to ensure that your mobile device, e.g. cell phone or a mobile broadband router is not too old to support the cellular services you need. For example, suppose you are using an old 4G LTE phone that was launched before LTE Advanced. In that case, the phone may not possess the necessary hardware or software to support the higher bit rates that LTE Advanced enables.

LTE networks have a concept of device categories where the latest device category is the most up-to-date. The device category is usually represented by the abbreviation “Cat”, so if an LTE phone is described as Cat 18, it means that the phone is classified as a category 18 phone.

The best way to see the detailed specifications for your mobile phone is by visiting GSM Arena’s website and entering your phone model. The specifications for your phone show which network technologies (e.g. LTE, CDMA, 5G NR) it supports.

You can also speak to a mobile operator to learn more about a specific mobile phone. If you find out that you have an outdated device or if your device is faulty, then a device update can potentially help speed up your mobile data.

What if your mobile data is slow all of a sudden?

If your mobile data speeds were at an acceptable level earlier and changed suddenly, then it is essential not to jump to conclusions too quickly. Instead, starting with some “home remedies” is better, such as restarting your phone to ensure your device is at least fresh. Below is a list of things you can do to ensure that all angles are covered.

1Switch off your phone for a bit and then restart. Sometimes, simple steps like these can make the difference. Do not worry too much about removing the SIM card and reinserting it if your phone is in the connected state (i.e. showing the signal bars and symbols like LTE etc.).
2Make sure you do not have any data-hogging apps in the background that are eating up your data speed. In addition, it is a good idea to uninstall any unnecessary apps you do not use frequently.
3Make sure your phone is not locked to an older network technology like 2G or 3G. So, if you have a 5G phone, make sure your preferred network is set to 5G. Similarly, if you have a 4G phone, make sure your preferred network type is set to 4G. Cell phones are backwards compatible, so if your preferred network is set to 5G, your phone can still access 4G and earlier technologies.
4Finally, if you have another device handy, e.g. someone else’s phone that is not older than your own phone, you can insert your SIM into that phone to check if the results are the same. That can help you identify if the issue is with your phone. For this one to work, you need an unlocked phone.

Mobile networks can often run into capacity issues due to maintenance or network faults. Also, if there is a sudden increase in data usage, e.g. lots of people watching an important football match, the network can get very busy, slowing down the mobile data speeds in general.

Also, if you live close to a train station or stadium or a big shopping mall where big crowds gather, there may be times when your mobile data speeds go down during busy hours. But if you have a good mobile operator, they will manage the necessary capacity demands by investing in additional network resources to address the needs.

Here are some helpful downloads

Thank you for reading this post. I hope it helped you in developing a better understanding of cellular networks. Sometimes, we need extra support, especially when preparing for a new job, studying a new topic, or buying a new phone. Whatever you are trying to do, here are some downloads that can help you:

Students & fresh graduates: If you are just starting, the complexity of the cellular industry can be a bit overwhelming. But don’t worry, I have created this FREE ebook so you can familiarise yourself with the basics like 3G, 4G etc. As a next step, check out the latest edition of the same ebook with more details on 4G & 5G networks with diagrams. You can then read Mobile Networks Made Easy, which explains the network nodes, e.g., BTS, MSC, GGSN etc.

Professionals: If you are an experienced professional but new to mobile communications, it may seem hard to compete with someone who has a decade of experience in the cellular industry. But not everyone who works in this industry is always up to date on the bigger picture and the challenges considering how quickly the industry evolves. The bigger picture comes from experience, which is why I’ve carefully put together a few slides to get you started in no time. So if you work in sales, marketing, product, project or any other area of business where you need a high-level view, Introduction to Mobile Communications can give you a quick start. Also, here are some templates to help you prepare your own slides on the product overview and product roadmap.

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