Messaging is an integral part of mobile communications, and there are multiple ways in which mobile networks can achieve it. For a customer, real-time messaging can be services like Short Message Service (SMS), Multimedia Message Service (MMS) and online Instant Messages (IM).
SMS or Short Message Service or text message is a text-only messaging service that allows customers to send messages of up to 160 characters; MMS or Multimedia Messaging Service is a service that enables customers to send text messages that contain media content like emojis, photos and videos.
What does SMS (Short Message Service) mean?
SMS stands for Short Message Service, but many of us know SMS as “texts” or “text messages”. It allows us to instantly and securely communicate with other mobile phones and computer users. As SMS is a native app on all mobile phones, it is the default messaging service hosted by mobile operators.
Nowadays, we frequently use WhatsApp (and other similar apps) to send all kinds of messages, including text, emojis, photos, videos, audio clips and links. However, SMS is still one of the most widely used messaging services to reach mobile phone users, and many businesses also use it for marketing communication.
SMS and text messages are two terms that are synonymous with each other. SMS is a text messaging service specified by the standards organisation 3GPP (Third Generation Partnership Project) and is enabled by specific components within a mobile network to ensure a secure delivery.
SMS is a text-only service with a limit of 160 characters (for Latin characters), including alphabets, numbers and symbols. This limit varies for other languages. The SMS service on mobile phones was introduced in the early 1990s, and now it is one of the most widely used services within the cellular industry. Due to its superior security compliance, SMS is used by many mobile operators for sending confidential information to their customers.
How does SMS work on a mobile phone?
Sending a text message from one device to another requires connectivity of some kind. For example, when delivering an SMS message through a 2G GSM or 3G UMTS network, the circuit-switched part of the network is engaged to deliver an SMS which is the same part of a 2G or 3G network that enables voice calls.
It means that the mobile network does not use mobile data (internet) to send or receive SMS in 2G or 3G network but instead utilises dedicated circuits and an additional network entity called Short Message Service Centre to store and forward text messages to the destination mobile phone numbers.
Our mobile phone communicates with the SMSC through a mobile base station closest to us when we send an SMS. The SMSC then forwards the SMS to the destination number through the mobile base station closest to the destination mobile phone.
A mobile network has many channels at its disposal for sending and receiving communication. These channels include control and traffic channels. When a mobile phone is not engaged in a call, it regularly communicates with the mobile network by sending and receiving signals through the control channel. This control channel is the communication channel used for sending and receiving SMS.
In 4G and 5G mobile networks, packet-switching is used for voice calls and sending/receiving SMS and MMS through VoLTE (Voice over LTE) and VoNR (Voice over NR) technologies. VoLTE and VoNR rely on the mobile core network to work with an entity called IP Multimedia Subsystem (IMS) to enable IP-based calls and messaging.
In the Apple world, when you send a text message as an iMessage from one iPhone to another, your mobile internet (cellular data) or fixed internet (Wi-Fi) is used when sending or receiving messages.
Is SMS free or do you have to pay for it?
The SMS service utilises specific parts of a mobile network, just like voice calling or mobile data. As a result, it has an associated cost for the mobile operator. In the past, SMS was one of the critical sources of revenue for the mobile operator; however, nowadays, many tariffs include very affordable rates for the delivery of SMS and MMS.
As a consumer, it is much easier nowadays to live without SMS or MMS if you are comfortable using messaging apps that require a WiFi or mobile data connection. That is especially useful when sending messages internationally or heavy files like recorded video messages from one phone to another. However, SMS is still a handy, secure and reliable service for important messages where delivery is crucial, e.g. messages from the government to people for COVID vaccinations.
What is MMS and how does it work?
MMS stands for Multimedia Messaging Service, and it is an extension of the SMS service. MMS allows you to send multimedia files, including emojis, pictures, videos and audio clips, in addition to the text message. It also has a higher limit on the number of characters than SMS.
As a general rule, mobile tariffs (mobile plans) do not include MMS by default and only include calling minutes, SMS and mobile data. However, since it costs money for a mobile network to facilitate MMS messages, especially in 2G and 3G networks, mobile operators charge for MMS as an out of bundle charge.
In today’s world, where most people use free social apps like WhatsApp on their smartphones to send and receive multimedia messages, MMS is still used as a service. Like SMS, MMS is part of the native “Messages” app on smartphones.
Since MMS is natively available on mobile phones, it is a particularly attractive service for businesses who want to promote their products to phone users (potential customers) by sending them marketing messages that include text, photos, videos, web links, etc.
In contrast to social messaging apps like WhatsApp, where you expect both the sender and the receiver to have the app, MMS messages do not have that dependency. For the MMS service to work, you need a device that supports MMS and a mobile tariff that permits you to send and receive MMS.
When a user sends an MMS to another user, e.g. sending a photo, the sender’s mobile phone establishes a data connection. If the mobile phone is not connected to a Wi-Fi network, it will consume mobile data included in your mobile plan. When sending an MMS, the message is first sent to the MMS Centre (MMSC) to check if the recipient’s mobile device is MMS capable.
If the recipient’s device is not MMS capable or if the recipient’s tariff does not permit MMS, the recipient receives an MMS notification message along with any text which contains a web link (URL) pointing to the MMS content. If the device and tariff permit MMS, the recipient’s phone establishes a data connection to retrieve the MMS content directly on the phone.
Usually, the MMS is displayed to the recipient as a photograph followed by any text from the sender just below the picture. If the recipient’s device does not support MMS or if it is not available on the recipient’s mobile tariff, the recipient receives a link that they can view in a web browser on any other device.
SMS stands for Short Message Service, and it is a service used by mobile networks for sending text messages. ‘Text Message’ is the generic term used for short message service (SMS). MMS stands for Multimedia Messaging Service, and it is a service used for sending messages with any media content, including pictures or videos.
Generally, when you purchase a mobile tariff, voice minutes, SMS (texts) and mobile data are included in your allowance but not MMS. MMS is usually a separate service and incurs additional charges for a customer.
As a consumer, an excellent alternative to MMS is free apps like WhatsApp that allow you to send app-to-app multimedia messages to those who use those apps. However, as MMS is built natively on the phone, it is not dependent on a phone user having to install third-party apps like WhatsApp.
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.