Recently Ericsson and Qualcomm have begun promoting their state-of-art technology, LTE-U. Is it any better that LTE-A, which is increasingly available all over the world, including US, Europe, Russia, China and so on? And what are these combinations of letters supposed to mean anyway?<\/p>\n
Let\u2019s start with the name. The first abbreviation, LTE-A, stands for \u201cLTE-Advanced\u201d, or \u201cadvanced 4th gen mobile network.\u201d Such networks have been rolling out all around the world. As for LTE-U, it is by no means some \u201cLTE-Ultimate\u201d or \u201cLTE-Unbeatable,\u201d,as some may think. \u201cU\u201d stands for \u201cUnlicensed\u201d here. So, this mobile network technology relies on the use of the so-called \u201cunlicensed\u201d frequency spectrum.<\/p>\n
Now, what does \u201cunlicensed\u201d mean here? That\u2019s quite simple: the majority of radio frequencies, including those used by mobile operators or radio stations, are licensed. Those frequencies are controlled by a government authority and can be used only by those to whom the license to transmit on this frequency was issued.<\/p>\n
For low-capacity civil transmitters, unlicensed spectrum is used: anyone can use those frequencies to transmit the radio signal. This makes complete sense: imagine you had to obtain permission for each RC toy you purchased for your child! The main requirement for those operating in this \u201cfree\u201d radio frequency spectrum is certain maximum limit of the transmission power in order not to disturb operation of other people\u2019s appliances.<\/p>\n
For instance, 27 MHz range is used be RC toys, 433 MHz is for walkie-talkies, and 2.4 GHz and 5 GHz ranges are allocated for Wi-Fi routers. These ranges vary from country to country, which provokes certain compatibility issues.<\/p>\n
The concept of LTE-Unlicensed is based on the deployment of LTE networks using \u201cfree\u201d frequency ranges. Of course, we are talking about low-power base stations, i.e. femtocells and picocells designed for indoor use. The more free frequencies they are able to \u201caggregate,\u201d which means to bring together several parallel transmission channels into one, the higher data rates would be.<\/p>\n
One rogue thought would start to bug you immediately: why would we need Wi-Fi then? Well, no one is disposing of Wi-Fi; quite the opposite, the technology continues to serve its intended purpose, which is being the foundation of small local wireless networks.<\/p>\n
Initially, this technology was used to build broadband access networks just because there was no other option. After all, Wi-Fi as such lacks several features, which are critical for reliable broadband wireless networks: it does not deploy state-of-art functions to manage network efficiency in case of high number of connections, does not enable secure authorization or other things like carrier aggregation, which is the process of uniting several frequency ranges into a single transmission channel.<\/p>\n
LTE already has it all by design. Since the unlicensed spectrum consists of various bits and pieces residing in various frequency ranges, the ability to aggregate them all would enable higher bandwidth networks.<\/p>\n
\n4G is just beginning to become the norm, so why do we need 5G? \u2013 http:\/\/t.co\/vP3wDv1X8s<\/a> pic.twitter.com\/t9ZR5neEcN<\/a><\/p>\n
\u2014 Kaspersky (@kaspersky) July 3, 2015<\/a><\/p><\/blockquote>\n