eMBB topics are dominating 5G right now. This means a focus on pushing data rates of wireless devices well beyond LTE limits. Elucidating extensively on the emerging wireless test technology, Jayanth Ramachandran, Director – Market Development – (Wirelesscomm) ruminates about its future and R&S position and strength in this evolving technology. Edited Nub.
- What are the trends shaping wireless test?
Key technology trends shaping the wireless test industry are 5G cellular technology, the Internet of Things (IoT), and also wireless fidelity (Wi-Fi) and, moreover, the growing automotive market. 5G development is well underway and first networks are already launched. Also, the first 5G devices are available for fixed wireless access as well as for mobile applications in smartphones in different regions and markets.
eMBB topics are dominating 5G right now. This means a focus on pushing data rates of wireless devices well beyond LTE limits. The majority of 5G NR commercial deployments are expected in the FR1 frequency range (e.g. at 3.5GHz), however FR2 mmWave frequencies (e.g. 28 GHz and 39 GHz) are in focus as a key enabler for higher data rates. While FR2 is going to be a game changer, the mmWave technology aspect still faces many challenges. For example, true mobility requires beam refinement and sweeping in an active connection. This and other challenges drive the demand for high-performance test and measurement tools.
There is a massive increase in 5G FR1 (450 MHz to 6 GHz or recently extended in 3GPP to 410 MHz to 7.125 GHz) test requirements as 5G NR FR1 is going to be widely deployed. Starting now and continuing beyond the year 2020, mainly non-standalone (NSA) TDD but also FDD and some Standalone (SA) will be the key deployments enabling the wide acceptance of 5G NR. 5G NR in FR1, just like LTE, enables larger coverage areas, with indoor penetration, and overall reliability in a mobility environment. LTE applying high orders of carrier aggregation (i.e. 8CC), high orders of MIMO (i.e. 4×4) and high modulation up to 1024QAM and operated in NSA with 5G NR enables extreme data rates. FR2 can further enhance these eMBB data rates in limited coverage areas.
- With advanced and complex technologies like 5G keeping the market ebullient how wireless testing instruments evolve to cap the trend?
Rohde & Schwarz has developed its test and measurement portfolio to fully address the challenges evolving from the introduction of 5G. The instruments provide the required 5G NR functionality, for example, the relevant options on signal generators and analyzers to generate and analyze 5G NR signals in the uplink as well as in the downlink that are fully compliant with 3GPP Release 15. Full support of test models and the integration of the newly defined 5G NR fading profiles provide a head start to the test engineer. More importantly, Rohde & Schwarz has developed OTA solutions in order to solve this new 5G test challenge. Examples include the R&S PWC200 plane wave converter for massive MIMO base station testing. Or a new and innovative compact test system which has been presented for the first time at MWC2019 for radiation measurements on 5G mmWave devices in the range from 20 GHz to 87 GHz using a compact antenna test range (CATR). Finally, R&S test solutions also cover mobile network testing aspects. Scanners and smartphone-based test solutions allow to access basic parameters like coverage for each individual beam as well as the user experience in deployed 5G networks.
- Versatility, diversification while keeping the time-to-market window in mind, how challenging has this market become and what strategies does your company comply?
There are many challenges associated with 5G. One of the biggest challenges is the sheer flexibility of 5G. Features like subcarrier spacing (SCS), symbol duration, cyclic prefix duration, bandwidth, frequencies from 410 MHz to 52.6 GHz and virtualized (core network) functions make 5G complex. In order to fully test 5G, the test equipment needs to be incredibly flexible to reduce the need for dozens of different test solutions.
At Rohde & Schwarz, we have been focusing specifically on providing the industry with adequate test solutions across the entire wireless product development cycle. Secondly, because of the move towards mmWave, we have been successfully working to expand our measurement capabilities from conducted testing to over-the-air (OTA) testing that will play a major role in 5G FR2.
We are involved in nearly all areas of 5G wireless device testing. Protocol stack development, RF and antenna design at FR1 and FR2 frequencies, data performance, device reliability, service & repair, production/manufacturing, conformance (PTCRB/GCF), compliance (CTIA/FCC/ETSI) and network operator related supplemental testing, as well as mobile network testing, are all our specialties.
- Traditionally, RF experts used expensive equipment hence selected organizations used to buy high-end instruments. Given the demand of the market, do you think more economical signal analyzers can be availed with same specs and features for mass under buyable bracket?
Among our solutions for the midrange market are the new R&D and production test solutions family supporting 5G bandwidth and RF requirements, namely The R&S FSV3000 and the R&S FSVA3000 spectrum analyzers, available with up to 400 MHz analysis bandwidth and up to 44 GHz frequency and covering all relevant 5G NR frequency bands. Designed with an ease of use in focus, the R&S FSV3000 features an innovative user interface, helping users set up complex measurements in the easiest and fastest way. It is the right instrument in the lab and in a production line. The up to 200 MHz analysis bandwidth is enough to capture and analyze two 5G NR 100MHz carriers at once. The R&S FSVA3000 features an analysis bandwidth of up to 400 MHz, a high dynamic range and an outstanding phase noise of –120 dBc/Hz, delivering a performance which until recently was reserved for high-end instruments. Users are capable to perform more demanding measurement applications such as linearizing power amplifiers, capturing short events or to characterizing frequency agile signals. Both, the R&S FSV3000 and R&S FSVA3000 can measure EVM values better than 1% for a 100 MHz signal at 28 GHz, making the analyzer family great fit for analyzing 5G NR signals.
- 5G in the sub 6 GHz spectrum will employ signals that use 100 MHz or 200 MHz of spectrum, compared to only 20 MHz in 4G LTE systems. Hence need of new calibration techniques will be needed, what are your takes to it?
Indeed the increase in bandwidth, as well as operation at high frequencies, require access and compensation from non-linear components used in the test setup. Even cables and adapters, which have almost no impact on the test results in FR1, may become critical at FR2 frequencies. Signal generators and spectrum and signal analyzers from Rohde & Schwarz provide an easy to use correction functionality, which allows adding calibration files onto the instruments. This enables calibrated and corrected measurements applied in real time. A particular challenge results from the implementation of highly integrated devices, including antennas operating in the cmWave/mmWave spectrum. These devices require over the air (OTA) testing and additional shielded chambers. The test setup also has to be carefully calibrated in order to compensate for cable, antenna and over the air path loss. Mastering the OTA test challenge requires strong RF knowledge, which has already been available at Rohde & Schwarz for over 40 years.
- For mmWave, test economics must improve in order to scale mmWave technology from small volume applications to mainstream (high volume) consumer applications. Your focus into mmWave testing technologies.
For sub 6 GHz FR1, most testing is still conducted due to available RF connectors. However, in mmWave FR2 user devices will be tested OTA only, significantly affecting the overall test procedures. This means different test setups using anechoic shielding boxes are needed. OTA also requires usually far-field (FF) conditions. In order to reduce complexity and costs by minimizing the space between the DUT and measurement transceiver, indirect far field (IFF) methods have been introduced. IFF methods such as compact antenna test range (CATR) create far field conditions in close vicinity to the DUT by bouncing the signal with the help of a reflective mirror. Especially in OTA conformance testing in FR2 the “black box” method has to be applied. In this approach, it cannot be assumed that the person testing a device has knowledge about the device’s interior, such as the size and placement of the antenna(s). Thus, the entire device is considered a potential radiating element, since the actual antenna can be anywhere inside the device. This can also be addressed by a CATR setup easily since it creates a big quiet zone so the entire device can be covered.
These examples illustrate some of the challenges involved with mmWave range 5G testing.
- Lastly, your dominance in the wireless testing space, one key product, and your comments, respectively.
Our recently released, highly anticipated key product is the R&S CMX500 radio communication tester that allows for 5G NR signaling test in sub 6 GHz (FR1) and mmWave (FR2) frequency bands for 5G NR. The R&S CMX500 can be seamlessly integrated into an existing LTE test environment by interworking with the well known RS CMW500 which is the industry standard for LTE and LT-A testing and is also ideal for tests in 5G NR standalone (SA) mode. The solution makes it possible to comprehensively test the signaling protocol, RF parameters and IP data throughput rates of simultaneous LTE/5G connections in dual connectivity mode.