Will 3G and 4G LTE mobile phones work on 5G networks?

If you have an existing 4G LTE or a 3G phone, you may wonder what may happen to the phone when your mobile network operator migrates to 5G. Each new generation of mobile networks requires a new mobile phone compatible with the new cellular technology.

Your existing 3G and 4G phones will continue to work as usual when your mobile operator launches the 5G network; however, your 3G or 4G phone will not allow you to access the 5G network. The New Radio (NR) technology used by 5G requires new hardware in the phone, which is why you need a new phone.

—Short video that explains if your 3G and 4G phones will continue to work on 5G—

5G mobile networks have been launched in many parts of the world, and many people have questions about 5G phones and whether we all need to buy a new phone now. When a new cellular technology is introduced, it takes some time for its coverage to be mature enough to become the primary network technology. For example, when 4G LTE was launched, we relied heavily on UMTS/HSDPA/HSUPA in the initial years before 4G coverage reached enough penetration. Now that 4G LTE is the primary network technology, it will take some time for 5G to be available everywhere. Until then, we may find ourselves using 4G LTE networks a bit more, at least initially.

What will happen to my 4G LTE phone when 5G comes?

4G mobile phones will continue to support 4G LTE, 3G technologies like UMTS/HSPA/HSPA+ and CDMA2000, and 2G technologies GSM and IS-95. If your mobile operator decides to switch off their 3G and 2G networks (e.g. CDMA2000 and IS-95), even then, 4G LTE will still be available to keep you connected.

If you are currently using a 4G LTE or 3G UMTS or 3G CDMA2000 cell phone, you may have questions about the 5G compatibility of your phone. First, let’s talk about the 4G phones that are currently the most prevalent mobile phones. 4G mobile networks use the LTE cellular technology, which requires mobile phones to be LTE compatible. An LTE-compatible mobile phone essentially means a phone that can support all the technologies used by LTE, including OFDMA radio access, MIMO, LTE frequencies etc. Like all mobile phones, 4G LTE mobile phones are backwards compatible, which means they support 3G and 2G technologies in addition to 4G. When a mobile operator migrates to 5G, they are highly likely to keep their 4G LTE network operational because network migration is a gradual process and because most of their customers are currently using 4G. 5G requires a new technology, New Radio (NR) which is expected to co-exist and evolve with 4G LTE for a long time. Therefore, your 4G LTE mobile phone can continue to serve you for a long time. However, it is important to be mindful that when a new cellular technology matures, it starts to become the primary technology with a wider network coverage compared to the older technology.

What will happen to a 3G mobile phone when 5G is launched?

Your 3G cell phone will continue to work and support both 3G and 2G even when 5G is launched. However, if your mobile operator decides to switch off their 3G or 2G networks, you will need to buy a 4G or 5G phone or switch to another mobile operator keeping their 3G and 2G networks.

A 3G cell phone that operates on UMTS (Universal Mobile Telecommunication System) or CDMA2000 will continue to work when 5G New Radio (NR) technology is introduced. However, since mobile phones are backwards compatible, your phone will only support 3G and 2G technologies. If you want to access 4G or 5G services, you will need a new mobile phone that is compatible with 4G LTE or 5G NR technologies. If you buy a 5G phone that will automatically support 4G LTE and 3G technologies. If you decide to keep your 3G mobile phone, your cellular service depends on your mobile operator’s network plans. If the operator chooses to keep their 3G and 2G networks fully operational, you have nothing to worry about. However, if your operator decides to reduce the footprint of their 2G/3G network or switch them off completely, then you need to evaluate your options. The first and the cheapest option is to switch to another mobile operator that is keeping its 2G and 3G networks. The other option is to buy a new mobile phone that is either a 4G phone or a 5G phone. A 5G mobile phone is an excellent option if your desired mobile operator has decent indoor 5G coverage. I have written a dedicated post on how to buy a 5G mobile phone subscription to help you evaluate your options properly.

Is there an update that can convert your 4G phone to 5G?

You cannot convert your 4G LTE phone to a 5G phone by upgrading your device software. A 5G phone requires special hardware that allows it to work with the New Radio (NR) technology used by 5G networks. However, a 5G phone can support 4G, 3G, and 2G in addition to 5G NR.

Every new cellular technology requires a mobile operator to purchase new hardware for their radio, core and transport networks. The cell towers of a mobile operator need new radio units to support the 5G New Radio (NR) technology. These 5G base stations, gNodeB, require compatible hardware within your mobile phone to allow your phone to access the 5G mobile network. So, if you want to access the 5G network, your best option is to buy a 5G phone from a renowned phone manufacturer. The way to do that is to check your mobile operator’s website to see which phone models are supported by your operator. Have a look at our dedicated post on 5G compatibility if you want to find out whether your existing mobile phone supports the 5G technology.

How long will 4G mobile phones continue to work?

4G phones will work on 4G LTE networks and the earlier cellular technologies, including 3G and 2G. LTE is not going anywhere in the foreseeable future, and therefore, there is no rush to upgrade your phone plan from 4G to 5G. 5G networks are relatively new at the moment, and most 5G deployments across the world are non-stand-alone (NSA), which means they use a combination of 4G and 5G networks to offer 5G. The benefit of 5G connectivity you may notice on your mobile phone at the time of writing (March 2022) is higher data speeds and low latencies compared to 4G. Unless you plan to use your mobile phone primarily as a hotspot for tethering, you may benefit little from 5G. On the other hand, if you want to use 5G for high-speed home internet, getting a purpose-built 5G mobile broadband router is a better option than tethering. Have a look at this dedicated post on average 5G download and upload speeds to help you decide whether to stay on 4G.

Can I use a 5G SIM card in a 4G phone?

If you have a 4G LTE mobile phone, you can put a 5G SIM card in it; however, it will only allow you to access the 4G, 3G and 2G networks. If you want to access the 5G network, your 5G SIM needs to be inserted into a 5G compatible mobile phone that supports the New Radio (NR) technology.

The main requirement for accessing the 5G network is a 5G compatible mobile phone. SIM cards from 3G UMTS networks and onwards are backwards and forwards compatible. It means that your 5G SIM can work on any 4G mobile phone; however, the services will be limited to the phone’s capabilities. For example, if you have an old 4G phone, it may have limitations in accessing the full feature-set provided by LTE Advanced and LTE Advanced Pro networks, even if you have the latest SIM card from your mobile operator. I have written a dedicated post on the SIM card and phone needs for 5G services that clarifies what you can do with 4G and 5G SIM cards and phones.

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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