The technologies that wireless carriers use to get cellular and Internet connectivity to end users' mobile devices are often just a series of letters and numbers, and that can make them hard to decipher.
This guide to wireless technology terms can help you straighten out which protocols are which, which wireless carriers use them and where they use them. Plus, learn more about mobile device fragmentation and how 3G cards work.
CDMA (also sometimes called direct-sequence spread spectrum) refers to several protocols in 2G, 3G and 4G cell communications. It stands for "code-division multiple access" and is a kind of multiplexing that lets several signals use one transmission channel, improving the speed and use of available bandwidth. CDMA is used in ultra-high-frequency communications systems across the 800-MHz and 1.9-GHz bands, and it uses analog-to-digital conversion in tandem with spread spectrum technology.
Because the frequency of the transmitted signal varies deliberately in accordance with a defined code or pattern, the frequency can only be intercepted by a receiver with a response that's programmed with the same code. Trillions of sequencing codes exist, which makes cloning frequencies almost impossible, enhancing the security and privacy of transmissions.
Almost all the major wireless carriers in the U.S., including AT&T, Sprint, Verizon and T-Mobile, use CDMA technology. CDMA technology has several families of standards: the GSM family, CDMA2000 family and Mobile WiMAX family.
CDMA2000 is one of the most used standards in the U.S.Its underlying multiplexing scheme is CDMA, but the two are different and often confused – CDMA2000 is a version of the IMT-2000 standard, which was designed for 3G communications. Verizon and Sprint use the CDMA2000 family of standards, which includes Single-Carrier Radio Transmission Technology, 1xRTT, 1x Evolution-Data Optimized (EV-DO) Rev 0, EV-DO Rev A and Ultra Mobile Broadband.
An advantage of CDMA2000 is that it can use multipath signals to make cell signals stronger, and CDMA2000 drops calls less frequently than CDMA does. In rural areas, CDMA2000's analog capabilities trump those of GSM, and CDMA2000 can hold more users per MHz of bandwidth, because it has high spectral capacity. But channel pollution is a problem with CDMA2000; if there are too many signals in a user's phone but none is dominant, call quality diminishes. And there are no international roaming capabilities for CDMA2000 devices that don't have a GSM radio. CDMA2000 technology may also be phased out over the long term, because 85% of users internationally have GSM.
The Global System for Mobile communication (GSM) is a digital mobile telephony system that's used in the U.S., but more widely in the rest of the world. GSM works at either the 900 MHz or the 1800 MHz band, and it uses a variation of time division multiple access (TDMA), a digital wireless telephony technology. GSM compresses data so it can be sent down a channel with two other streams of user data in different time slots.
Long Term Evolution
Long Term Evolution (LTE) is a 4G wireless broadband technology developed by industry trade group, the Third Generation Partnership Project. LTE is the next step in a progression from GSM (2G) to UMTS (3G) and has superfast speeds -- 100 Mbps downstream and 30 upstream – less latency than 2G and 3G, scalable bandwidth and backwards compatibility.
Mobile service provider
Any company that offers transmission services to wireless device users through radio frequency signals – as opposed to through end-to-end wire communication – is a mobile service provider (MSP). They're sometimes called wireless service providers, wireless carriers or mobile carriers. Major MSPs in the U.S. include Verizon, AT&T, Sprint and T-Mobile. Though they offer different service plans, data speeds, devices and reliability, they all fall under the MSP umbrella.
Mobile device fragmentation
Mobile device fragmentation can occur if you drop your smartphone, but that's not the kind we're talking about. When there are several different versions of the same mobile OS at the same time, it creates mobile device fragmentation -- fragmentation of the operating system. Usually, fragmentation happens when wireless carriers are in charge of sending updates to users. If the OS manufacturer is in charge, it can just send an update to users, the way Apple does with iOS updates. But Google and others leave update deployment to wireless carriers, and those wireless companies can delay delivery. This fragmentation causes problems for IT, because different devices and OS versions have different capabilities, which makes them harder to manage and secure.
Over-the-air (OTA) updates wirelessly send software or data to mobile devices. Wireless carriers use OTA updates to configure devices and to send firmware, and carriers and manufacturers now use over-the-air updates to send OS updates. Before OTA updates, users had to physically connect their devices to computers to get new software or data updates.
3G is a combination of spread-spectrum radio transmission technologies that cell providers use to create wireless mobile networks. 3G cards let devices wirelessly access the Internet via an MSP's 3G network. To get to the Internet with a 3G card, the user has to contact a wireless carrier, pick a plan and buy a 3G card that fits their device. Or, users can buy a device with a built-in 3G card, such as a smartphone. External cards usually have antennas and come in various forms, such as internal USB drives, external PCI cards and PCMCIA and Express cards.
This was first published in March 2013