What are the challenges that test instrument companies face while delivering solutions to the 5G ecosystem?

Speaking from Rohde & Schwarz's point of view, 5G challenges us to stay ahead of our customers, the designers. The next generation of mobile networks, 5G, introduces a paradigm shift towards a user and application-centric technology framework, with the goal of flexibly supporting three important use case families:

• Enhanced mobile broadband (eMBB) focuses on supporting the ever-increasing end user data rate and system capacity.
• Massive machine type communications (mMTC) targets the cost-efficient and robust connection of billions of devices without overloading the network.
• Ultra-reliable low latency communications (URLLC) will be necessary for applications such as autonomous driving and remote surgery, and cloud robotics for Industry 4.0.

Taking a look at one of these use cases—mMTC—we think that Narrowband IoT (NB-IoT) will become a key technology and operate inside the 5G NR frequency bands, similar to LTE today. NB-IoT largely resembles LTE, and testing NB-IoT devices is similar to testing an LTE modem. However, specific LPWAN application features require particular attention. For example, detailed analysis and optimization of power consumption under different configurations and operational models is highly recommend to ensure a battery life of more than 10 years. 

Operations under extreme coverage conditions require best-in-class RF and antenna designs, which are ideally verified by over-the-air testing. It is also recommended to analyze the impact of different CE levels on power consumption and latency as well as operation under different fading conditions. End-to-end application testing and, in particular, verifying secure and private communications behavior of NB-IoT devices is also of interest.

However, we have to work both with - and ahead - of our customers, especially in areas such as phased array antenna design for massive MIMO. We had an event recently in Silicon Valley (RF Lumination) in which we demonstrated and gave courses with partners such as Texas Instruments, IDT and TRW (Northrup Grumman) on exactly this topic: 5G test challenges. You can get the papers here.

Test and measurement solutions will be a key link in the commercialization cycle. The initial 3GPP specification drafts for release 15 introduce new antenna concepts with controllable/steerable beams, new spectrum in the mmWave frequency bands, and very wide bandwidths compared to LTE today. In hybrid beam forming systems using phased array antenna technologies for mmWave mobile access, the test equipment must not only step up in frequency to the mmWave bands, but key performance metrics must also be characterized beam-by-beam because of the directional nature of transmission and reception at these frequencies. 

Additionally, while bandwidth is a familiar test challenge, the tested bandwidth with 5G may increase by 50x over a standard LTE channel. At these bandwidths, the test systems must only generate and acquire these wider bandwidth waveforms but must also have the processing capability to process all data. And to make things even more complicated, in an over-the-air (OTA) scenario, these samples must be processed real-time. While there has been much focus and excitement regarding 5G, the challenges that test instrument vendors face delivering solutions to the 5G ecosystem have perhaps been overlooked. These challenges must be solved before 5G can go mainstream and prime time is just around the corner. 

Test equipment vendors must develop cost effective, flexible solutions that are software configurable to address the challenges presented by 5G. It seems clear that FPGAs must certainly be a part of these systems due in part to their software programmability and immense processing capability. With 5G getting closer, it’s the test and measurement industry’s turn to innovate.