A Little LTE for You & Me: Build Your Own LTE Network on a Budget

If you ’ re in a engineering function in the cable industry, you ’ re probably mindful that cable is undergoing a tectonic shift from “ the future is wired ” to “ the future is wireless. ” Wireless means a set of things to a batch of people. In the past, radio receiver meant Wi-Fi if you were talking to a cable nerd. But today, radio receiver is quickly shifting to mean fluid, or more specifically 4G LTE and/or 5G. For those of you interested in this radio receiver future, below, I ‘ll explain how you can build your very own LTE network on a budget .

Time to Tinker

I learn good by doing. Growing up this always terrified my parents. now that I ’ ve matured a spot ( eh hem ), this tendency manifests less as a gamble of bodily damage and more as time spent in the lab tinker. My tinker target as of late has been LTE networks. It turns out there are unfold source solutions and low-cost parts out there that let you build a simple LTE network ( eNB + EPC ) for about $ 1500. I ’ ve been studying LTE since about 2013, but the survive copulate of months building and configuring LTE components in the lab have taught me about a much as the anterior years combined .
In addition to the capital learnings that came from my efforts, we ( CableLabs ) have ended up with a great instrument for research and experiment. With a cheap and fully exposed source LTE network we can explore fresh use cases, configurations, and deployment architectures, without the need for outside collaboration. Don ’ triiodothyronine get me wrong, we love collaborating with industry partners here at CableLabs, but it ’ s great to kick the tires on an estimate before you start engaging outside partners. Using this apparatus, we have the freedom to do just that .

Hardware

The hardware apparatus is square :

  • Two Intel quad-core i7 PCs
  • A software-defined radio
  • A SIM card
  • The UE

An case bill of materials is below. surrogate of any device with a similarly specification ’ five hundred product from a different manufacturer should be fine ( this list is not meant to be prescriptive or seen as an sanction ) .
Build your own LTE Network on a Budget


Software

For both machines, we use Ubuntu as our OS. The LTE system software comes from an open source project called Open Air Interface ( OAI ). This OAI software is broken into two projects :

  1. The eNodeB (eNB) called “openairinterface5G”
  2. The evolved packet core (EPC) called “openair-cn”

calculate 1 shows the LTE functional elements included in each project :
Open Air Interface Functional Elements
once downloaded and built you get four executables : eNB, HSS, S/PGW, and MME. With my limited Linux chops, it took me a pair of days to get everything happy and running. But for a Linux ninja, even one with express LTE cognition, it can be astir and running in a day.

For aid getting it going, OAI has a capital wiki with a crowd of how-to doctor and mail lists that are quite active. In summation to the great doctor on the OAI wiki, do some google and you ’ ll see many forum posts and how-to sites around the web, for example, here is a great tutorial for doing EPC + eNB in a unmarried personal computer .
It largely works. It ’ sulfur open source, so the stability is all right, but don ’ t expect weeks of uptime. besides, note the SGW and PGW are a single feasible, so the S5/S8 interfaces are not exposed, evening though it ’ s a solid line in digit 1. Does this limit your plug-n-play interoperability testing a sting ? sure, but overall the solution is tough to beat for the price .
Another thing to watch out for is UE interoperability. many phones cultivate, for exemplar, the Samsung S7, Moto G4, but others don ’ metric ton. LTE has many variations on the impound procedure, but not all are supported by OAI ’ s EPC presently. But again, it ’ south barren ! And it supports some mainstream readily accessible phones, which is pretty angelic .

Other Things to Consider

So we discussed the basics, but there are a match of other bits you need to line up to get everything work :

  • Even though this set up is for tinkering, you will need a plan for regulatory compliance if you want to go over-the-air. For example, in the US you’ll need to contact the FCC to apply for a Special Temporary Authority for the frequency of your choice. Alternatively, you can do all of your testing conducted over cables in your lab. In that case, a UE with external antennas becomes really handy, e.g., the Huawei B593 family of products is what we have used (added bonus that it works great with the OAI EPC).
  • You will also need to get some SIM cards. SIM cards are wildly more complicated than I ever realized! My best advice is to go to the experts for help. Gemalto is the tier 1 provider. If you are a tier 1 kinda person, maybe start there. We have also found SmartJac to be super helpful. In either case, I advise starting with the OAI default SIM data set. It will make your initial connection efforts that much easier. Once you get that working, if you want to change the details, you can use a SIM editing software from either Gemalto or SmartJac.

Now do something cool!

nowadays that you are armed with some cognition, go forth and make some LTE ! post in the comments if you have questions, want to partake your stick out, run into issues, post in the forums I linked to, or on the reflector… you get the idea…


We barely announced our new TIP Community Lab where engineers will have entree to a bevy of state-of-the-art wire and wireless test equipment. Make surely to read my web log post “ CableLabs Introduces New Telecom Infra Project ( TIP ) Community Lab “ for more information and sign to our web log to find out about future innovations .

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