Don joined Award Solutions in 2005, bringing his knowledge and experience in mobile wireless technologies to bear in the planning, development and delivery of technical training seminars. Don specializes in wireless telecommunications networks, focusing on air interface and core network standards, wireless and Internet applications, and advanced wireless network solutions, such as ad hoc and mesh networking.Don has over 30 years of hands-on experience in the telecommunications and wireless industries. He began his career in Ottawa, Canada, with Nortel Networks (then Bell-Northern Research) as a call processing software designer. He moved to Richardson, Texas, in 1983, as one of the initial team responsible for designing and developing Nortel’s wireless product line. He rose quickly through the ranks, first as a development manager, then as a senior project manager, and then as a director of advanced wireless technology, involved in all aspects of the design of Nortel’s AMPS, TDMA and CDMA products. In his final role at Nortel, Don was responsible for a small technology group investigating advanced networking technologies, including self-organizing wireless mesh networks.Don is currently involved in developing and delivering courses for Award’s 4G (LTE) technology curriculum at many leading telecommunications companies. In addition to technology classes, Don conducts network planning and evolution sessions for large wireless service providers to help RF and core network engineers understand and plan for upcoming technology changes and enhancements such as VoLTE and LTE Advanced.Don received his Bachelor of Science degree in Computer Science (First Class Honors) from the University of British Columbia in Vancouver, Canada. He holds 9 patents in various areas of wireless technology.
If I were to ask you how fast you can go on LTE, you’d probably say 300 Mbps. That’s the number most often quoted as the peak downlink data rate for LTE. (Well, technically it’s 299.552 Mbps, but let’s not quibble over a few kbps.) The problem with that number is that it makes a number of assumptions about how the LTE network is configured; for example, it presumes that the LTE channel is 20 MHz wide and that 4x4 SU-MIMO is being used for the downlink transmission. But what other assumptions are hiding behind that number?
A Thoughtful Experiment
Let’s perform a quick thought experiment. Suppose an LTE user is downloading a very large file, and is watching the progress display on his device. What would it take for the data speed shown on the display to be as close to 300 Mbps as possible?
Consider the situation. The user has established a data session with an FTP server somewhere, and packets are flowing through the Internet, to the LTE network, over the radio interface, to the user’s device. The pipeline between the server and the user needs to be as large as possible (in order to maximize the data rate), and that pipeline needs to be kept filled (in order to sustain that data rate). What has to happen for this to be the case?
I’ve already mentioned a couple of things: we need a 20 MHz LTE radio channel, and 4x4 SU-MIMO. But let’s put a more comprehensive list together.
There may be a few other bits and pieces, but you get the idea. Achieving the maximum advertised data rate is not a trivial task.
So You’re Telling Me There’s A Chance
Can it be done at all? Absolutely. In a closed lab environment where the RF is clean and access is controlled, where the server is configured properly and is located right beside the cell, the (potential) capabilities of LTE have been demonstrated many times.
Will the average user see anything resembling 300 Mbps? Absolutely not. The chances that a random individual will happen to be in the right place at the right time, during exactly the right thing in the right way, are vanishingly small. To be fair, this statement applies equally well to any other wireless data technology, not just LTE; it is a rare event when a normal subscriber achieves a data rate even a third of the advertised maximum. Interestingly enough, it’s generally not the RF conditions or the traffic load on the cell that slows things down; it’s the application the subscriber is using, which rarely generates more than a trickle of data.
So what’s the moral of this story? Don’t worry about the number on the box, and enjoy a data experience that’s simply better than what you had before.