When consumers think about mobile network providers , their main needs are related to the quality of services, support, pricing and other factors. When you select a network operator, you also have to choose between a GSM or WCDMA network.
You probably came across these terms earlier when choosing a new mobile phone, connecting to providers for the first time or changing them. But do you know what they mean and what is the difference between them? To make the right choice, you should consider in more detail how GSM differs from WCDMA and which of them is better.
What is GSM?
GSM acts as the Global System for Mobile Communications and is currently considered a communications standard on a global scale, especially in Asia and Europe, with availability in more than 210 countries. It operates on four different frequency ranges: 900 MHz and 1800 MHz in Europe and Asia, and 850 MHz and 1900 MHz in the Americas. The GSM Association is an international organization, founded in 1987, which is designed to develop and monitor the expansion of the use of wireless communications of this standard.
GSM uses the TDMA (Time Division Multiple Access) option, which divides the frequency bands into several channels. In this technology, voice is converted to digital data that is transmitted through a channel and a time interval. At the other end, the receiver only listens for the assigned time interval, and the call combines both signals. Obviously, this happens in a very short time, and the recipient does not notice the “gap” or time division.
What is WCDMA?
CDMA, or code division multiple access, has become the standard developed and patented by Qualcomm and subsequently used as the basis for CDMA2000 and WCDMA for 3G standards. However, due to its proprietary nature, WCDMA technology has not received the global implementation that GSM has. Currently, it is used by less than 18% of networks worldwide, mainly in the USA, as well as in South Korea and Russia. What is the difference between GSM and WCDMA from a technical point of view?
In WCDMA networks, digital calls overlap, assigning unique codes to differentiate them. Each call signal is encoded with a different key, and then they are transmitted simultaneously. Each receiver has a unique key that can split the combined signal into its individual calls.
Both standards have multiple access, which means that several calls can go through one tower. But, as you can see, the main difference between them is related to how the data is converted into radio waves that your phone transmits and receives.
The main reason telecommunication companies have problems quickly deploying a new format is the difference in the frequency ranges that they use. Because of this, phones released with only GSM support could not communicate with WCDMA networks, and vice versa. To get around this, most device manufacturers had to use multiple frequency bands for 2G and 3G networks. This ensured that mobile phones could be used on virtually any network and anywhere in the world.
WCDMA or GSM: what's the difference?
Before the advent of 4G LTE technology, the obvious difference between GSM and WCDMA devices was related to the SIM card. GSM phones came with a SIM card slot, but CDMA devices did not.
In other words, WCDMA is a phone-based standard with a subscriber number associated with a specific device that supports 3G. If you want to switch to another phone, you will need to contact the provider, deactivate the old device and activate the new one. On the other hand, in GSM devices, the number is connected to the SIM card, so when switching to another device, all you need to do is put the SIM card in a new phone.
Network coverage
Network coverage does not depend on whether it is GSM or WCDMA. What is the difference in this case? This characteristic is more likely dependent on the infrastructure that the operator has. GSM networks are much more popular worldwide, with the exception of the United States, where Verizon Wireless, the (W) CDMA network, boasts the largest number of subscribers in the country.
International roaming
When connecting within the country, it does not matter which network you use if its coverage is sufficient. So, in Russia you can freely use WCDMA or GSM. What is the difference outside the country?
When it comes to international roaming, GSM has a lot of advantages: there are much more of these networks around the world, as well as many roaming tariffs between these providers. With a GSM phone, you also have the advantage that you can purchase a local SIM card wherever you are (provided that you use an unlocked device). In turn, you will not be able to get full access to the WCDMA data connection, depending on the device and network compatibility.
4G, WCDMA or GSM: what is the difference in the near future?
With the advent of 4G and the adoption of LTE and LTE-Advanced as the standard by most network operators around the world, the debate over GSM and WCDMA takes less time. Today, you may notice that the latest smartphones designed for WCDMA networks also come with SIM card slots to take advantage of the 4G LTE features on the network.
The difference between GSM or WCDMA devices leads to the fact that they cannot be interchangeable even now and will never be cross-compatible, but in the near future this will not make any difference. This is due to the fact that modern developers continue to move towards a full transition to 4G LTE. This technology has obvious advantages.
So, in international roaming, the main factor is the quality of the voice call and the satisfaction of user needs for 3G data. These options can be equally good on GSM or WCDMA networks. What is the difference? The 3G modems built into these devices can show high functionality. But regarding factors such as accessibility, coverage and price of services, 4G offers the best conditions.