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As the communications industry gets closer to demystifying the needs and requirements of implementing new 5G network technologies, there’s lots of opinions on what the standards should include and what direction the industry should take. But there’s one thing that pretty much everyone can agree upon – it’s complicated. Really complicated, and we’re barely cracking the surface on the challenges that lay ahead. Not only in developing, but also testing these new technology scenarios such as 3D channel propagation models, massive MIMO configurations, interworking with legacy systems and the super high-performance requirements of rich multimedia services that are a promised result.
Massive MIMO can make Testing Massively Complex
Let’s take a closer look at just one of those challenges – testing massive MIMO. MIMO channel model propagation is a complicated subject, even for a small number of antennas at both ends. A channel emulation system must be able to represent all the typical propagation conditions along a specified radio link. This includes interference, bounce (multi-path), Doppler fading, delays, etc., with each antenna pairing (device to base station and back) producing its own path. In 4G, base stations can have as many as eight antennas and devices as many as four. This produces configurations as high as 8x4 MIMO, which translates to 12 bidirectional ports and 64 digital links (8x4x2=64), where each link represents a connection between one base station antenna and one mobile antenna.
And in Moving to 5G, the Numbers Increase Exponentially
When you move to 5G, the number of antenna elements per base station increases exponentially, thus increasing the quantity of ports and digital links needed to build and emulate those configurations. The figure below gives a snapshot of these scenarios for as many as 128 antenna elements, but estimates show that 5G configurations will go higher than that, especially at millimeter wave frequencies.
To comprehensively test these environments, every individual link (or path) must be parametrized and emulated. Even for the simplest method of conducted testing, this typically entails hours of setting up hundreds of physical cables and channel model configurations via spreadsheets or worse, manual entry. When test configurations move to 5G over-the-air or phase matrix methodologies and you need to account for various 3GPP mobility scenarios, the setup and definition of channel models gets even more complicated. Designing meaningful test cases becomes extremely time consuming and so difficult that only skilled experts can create them with conventional methods.
There’s a Better Way to Test
Spirent’s mission was to develop a way to shield our customers from all that complex setup effort. Our new Advanced Channel Modeling (ACM) software is a user-friendly, graphically-based application that allows you to create the scenarios you need - in less time and without all the back-end calculations. You can then use the resultant models to perform the desired tests with Spirent’s Vertex channel emulator. ACM gets performance testing abstraction one level higher; that is, you can focus on creating scenarios from templates instead of figuring out how to set up the lab system and design all the channel models.
Design, View, Build and Play Real-World 3D Propagation Scenarios
ACM allows you to create truly meaningful test cases for 5G system-level performance tests for massive MIMO applications. One single interface can create mobility test scenarios with handovers in an intuitive way for standalone, phase matrix, over-the-air test configurations, or Virtual over-the-air (VOTA), coupling the complex 3D propagation environment to each scenario.
Since ACM has a completely open interface (i.e., the resulting 3D channel model file is an ASCII txt file that can be loaded to any tool), it can be used without the Vertex channel emulation platform in early phases of the R&D cycle to investigate network-level propagation effects.
Seeing is believing. Contact Spirent to learn more about this exciting new software or request a demo session. A new day of channel emulation has dawned. And the good news is? We’ve simplified it.
