How to Build Your Private LTE Network

Private LTE networks are becoming more popular due to the reduced complexity and operational costs. Historically, building cellular networks was limited to large corporations with deep pockets. Licensing frequency bands, purchasing radio infrastructure, and developing and maintaining the core network layer are resource-heavy investments, until now. Building a private LTE network can be “easily” accomplished. Read along to find out how to build a private network.

The Benefits of Private LTE

Running networks privately allows for improved quality of service, lower latency, and better data security. As a private network operator, you are in control of the physical and digital infrastructure. To improve network coverage in remote or radio-hostile areas, additional base stations can be installed.

The digital infrastructure is responsible for managing cellular connections and secure data routing. The so-called Core Network can be installed on a private server to ensure the data never leaves a trusted domain or physical site.

If data processing happens locally, latency can be reduced dramatically, which opens up new opportunities for novel use cases. When running networks privately, you are also in control of your expenses. After the initial CAPEX investments of purchasing and installing the physical infrastructure, OPEX is reduced to near zero as data charges don’t apply.

"If data processing happens locally, latency can be reduced dramatically, which opens up new opportunities for novel use cases."

-Monogoto

How to Set Up Your Private LTE Network

The 5 things required for running your private LTE network are:

1. Frequency Spectrum
2. Physical infrastructure
3. Digital infrastructure
4. Customer Premise Equipment
5. SIM cards

Let’s discuss all components one by one.

1. Frequency spectrum – Licensed, Unlicensed, or Shared

Licensed Spectrum
Licensing the rights to use specific frequency bands can become quite costly. Spectrum is usually licensed by a federal organization through spectrum auctions. As spectrum is a scarce resource, you need millions if not billions to license part of it. Luckily, some network operators are willing to sublicense parts of their spectrum, allowing you to build your private LTE network.

Unlicensed Spectrum
Some parts of the spectrum are unlicensed and can be used without approval from the authorities as long as the hardware is certified. E.g. you don’t have to go through a legal procedure to set up a WiFi router. Depending on the country you’re operating in, you may be able to use unlicensed spectrum for your private LTE network.

Shared Spectrum
As of 2015, the FCC in the United States opened up the 150 MHz bands for shared use, allowing companies to deploy private networks without the need to license spectrum. This band ranges from 3550 to 3700 MHz and is also referred to as the 3.5 GHz band, LTE Band 48, or CBRS (Citizens Broadband Radio Service). The CBRS band can be used commercially and doesn’t require heavy investments to license the specific frequencies. CBRS is perfectly suited for running private LTE, or even 5G networks.

2. Physical infrastructure

To build a private network, specific hardware is required. This is referred to as eNodeB, base stations, small cells, or CBSD (when the hardware is designed for the CBRS band). eNodeBs form the bridge between the physical and digital world as it translates electromagnetic radio waves to digital data. It communicates with physical end devices as well as with the digital core network.

Although public LTE infrastructure looks large and expensive, you can already purchase small eNodeBs for a couple of hundred dollars. Vendors include Baicells, Airspan, Foxconn, Telrad, T&W, and Ubiik to name a few.

3. Digital Infrastructure

The Core Network, also referred to as the Evolved Packet Core (EPC) is the digital network component that manages the device connections, and routes data to the right endpoints. It contains two components: the Control Plane and the Data Plane. The Control Plane is responsible for tasks such as authentication and generating encryption keys for the user equipment, and for managing and configuring the eNodeBs. The Data Plane takes care of the actual routing of telemetry data.

4. User Equipment

User Equipment (UE) refers to the devices which use the private network. Often, UEs contain sensors to sense their physical surroundings and send data to the cloud. They require a cellular radio modem that supports the frequency used by the cellular network.

Devices running on the network may also be Customer Premises Equipment (CPE). CPEs convert the LTE networking signal to a different communication standard such as WiFi or wired ethernet and vice versa.

5. SIMs

In order to set up a private LTE network, SIMs are required. Each SIM contains an IMSI which is a unique code describing the subscriber identity, as well as some security keys.