5G is an evolution of today’s LTE technology with the addition of new radio access technologies, often in higher frequencies. 5G will influence the entire mobile network and associated eco-system, from devices to radio access, IP core and into the cloud. It is expected that 5G service will start in 2020 and its development is being driven by new use cases that will impact both consumers and business. New applications and use cases anticipated for 5G include safety, connected cars, remote robots, drone and fixed wireless access – rivaling fiber capacity – for residential homes. As a result, mobile operators worldwide are planning for their 5G future.
According to new research commissioned by wireless telecommunications company, Qualcomm, 5G technology will have the same economic impact as some of the biggest innovations mankind has witnessed in recent history such as electricity, the steam engine, and the internet due to its status as a ‘general purpose technology’. It’s expected that 5G will be used to enhance everything from mobile broadband to the Internet of Things (IoT). With $200 billion to be invested annually in the 5G value chain, the research estimates 5G will create $12.3 trillion of global economic output by 2035.
Operators committed to introduce 5G/LTE Advanced
The Importance of 5G Testing
Publishing 5G new radio (NR) standards is a welcome sign to engineers at chipset and device developers, as well as carriers. Test companies will also benefit from having a better map to follow as the industry continues down the path to 5G. For engineers who are developing systems for the next generation of wireless networks, this poses many challenges, including how to verify their designs. Among the most difficult obstacles are the evolution of the standard, millimeter wave (mmWave) adoption, and controlling the cost of test.
5G’s focus on mmWave for mobile access is going to introduce new test challenges. Semiconductor companies are developing transceivers with integrated phased array antennas removing cable access common to LTE and other commercial wireless devices today.
With no cable access these devices must be tested over the air. OTA testing entails several different challenges including repeatability, configuration, and coverage. Several companies have put forth proposals to address these test challenges but questions remain in terms of accuracy, test time, and ultimately cost. Whatever is included in the RAN4 documents, 5G components and devices must be tested differently with new techniques and technologies from their 4G predecessors.
With the 3GPP forging ahead with 5G NR, there is no doubt that considerable progress has been made and will continue to be made in the next year. The 5G momentum is unstoppable. The lens now falls on the practical aspects of developing a multi-vendor wireless standard, and the test & measurement players must step up and play a key role in moving the 5G agenda forward.
Not only that, Telecom engineers have noticed the evolution of 5G technologies and challenges encountered in test and measurement by these new technologies with regard to design, characterization, validation & mass manufacturing.
With the implementation of 5G over the next decade, both network equipment manufacturers (NEMs) and operators will face new challenges in testing their hardware, software, and end-to-end deployments. 5G technology, as currently envisioned, is quite different from 4G/Long Term Evolution (LTE) and will bring together some of the most challenging aspects of existing approaches and introduce new challenges.
What is needed is a new approach for 5G test architecture that will help operators and equipment suppliers validate their hardware, software and configurations to ensure they perform as expected and deliver an excellent customer experience.
Technical Challenges of the 5G Testing
- A complete data-centric 5G network with a very wide and diverse set of applications to test will require a great effort in standalone testing
- Test automation, monitoring and built in test solution will be essential for analyzing properly the performance of such a top-notch networks
- As 5G will bring many new test requirements and challenges by the use of SDN/NFV and cloud services, the technology can also be used for creating new test solutions that address these markets.
- Keeping this in mind, cloud solutions are also seen as both the new demand and the new solution for 5G network and device testing
Solving the 5G Testing Challenges
Even though the first version of the standards will be released by year’s end, 5G remains a bit of unchartered territory. When the industry moved from 3G to 4G, the transition was made smoother by similarities such as frequency coverage, propagation and many other parameters. That is not entirely the case with 5G. While LTE technology will be leveraged in many 5G applications, mmWave frequencies will be used to accommodate the high-bandwidth services expected with the rollout. It’s interesting to note that between 28 GHz, 37 GHz, and 39 GHz, there is 3.85 GHz of bandwidth available—six times the amount of spectrum the FCC has ever authorized.
The first spec outlined in the December 2017 3GPP standard will focus on the non-standalone (NSA) mode. NSA will utilize existing LTE radio and the evolved packet core network as an anchor for mobility management and coverage. It will also add a new radio access carrier to enable certain use cases, namely fixed-wireless broadband. Early 5G deployment will have dual connectivity that will enable the networks to provide multi-standard and multi-band support in both devices and radio access. Core mobile device actions, such as scheduling and handovers, will be conducted using the LTE channel to leverage its broader coverage. mmWave will serve as the data pipe, as it provides much faster throughput for high-bandwidth services.
A second 5G mode is standalone (SA). This version, as the name implies, can be deployed in Greenfield situations and won’t rely on existing LTE elements. The first version of the 3GPP specification is not expected to address SA, leaving engineers to speculate on the conditions of this mode. Further complicating matters is that there will undoubtedly be revisions made to the NSA specifications over the next few years.
Even though LTE will be an integral part of 5G, mmWave will have a strong role because of its throughput advantages. Aggregated Channel bandwidth in mmWave bands is expected to be 1 GHz and higher, significantly wider than the 20 MHz offered by LTE. There are some tradeoffs associated with the ability to transmit considerably more data. High frequency results in shorter wavelengths. In the case of mmWave, the range is 1 mm to 10 mm. Signal power can also be easily diminished due to the higher frequencies’ vulnerability to gases, rain, humidity absorption, and foliage. As a result, mmWave can only transmit for short distances and will need Line of sight (LoS) propagation.
To compensate for limited transmission distance and operation in Non-Line of Sight (NLoS) environments, smart beam forming and beam tracking will be integrated into 5G transmissions. Beam forming, as shown in Figure 1, is a traffic-signaling system that identifies the most efficient data-delivery route to a user, as well as reduces interference for those nearby in the process. Beam forming is an effective technique in helping massive MIMO arrays makes more efficient use of nearby spectrum.
Data is transmitted to specific devices via Beamforming
Beamforming and other mmWave applications create test challenges, as engineers must conduct static tests on devices and antennas in active beam forming environments. Engineers must find how many points are necessary to obtain an accurate measurement, but not too many that tests are inefficient and costly. One of the most important tests on mmWave devices is propagation loss. As previously stated, signal power at high frequencies can be diminished by environmental conditions. At 28 GHz, loss is approximately 40 dB higher than at LTE frequencies. This is considerable when you account for the fact that total power is reduced by half for every 3 dB of loss.
Testing is different as it relates to the next generation of mobile devices. While current mobile terminals have several built-in antennas, those for 5G will have significantly higher antenna counts. Additionally, antenna arrays are embedded in the chip of a 5G mobile device, making it significantly more challenging for engineers to verify their performance. Implementing a measurement connector for each antenna would cause problems with mobile-terminal size and contradict cost reduction trends.
Traditionally, two test chambers—the reverberation chamber and the more-expensive anechoic chamber—are used when performing OTA measurements. Studies indicate that better results are achieved by conducting far-field measurements (FFM) on mmWave designs. Using this as a basis, OTA measurements will have to be taken 1.5 m to 2 m on devices supporting 28 GHz. That will require a significant investment, as the test chambers would be considerably larger than those currently used for LTE.
Cost of Test
Reducing the testing costs will play a key role in the success of 5G. If there isn’t a compelling business case to deploy 5G services, the technology may not roll out as expected. To control test costs, engineers must make the decision as to which tests need to be done in an OTA chamber. Chipset, device, and carriers all must agree on an acceptable margin of error for certain performance parameters to eliminate the need for some OTA tests. For example, there will be a considerable amount of protocol tests that will need to be performed. Because verifying the protocol stack does not require RF measurements, protocol testing may be done without a chamber.
In a greater test sense, working on economic efficiencies can be achieved through design of the test solutions. Vigorous, integrated platforms whereby capabilities can be efficiently added as needs expand will allow for a greater ROI on the test investment. It will also simplify adding test cases that address new versions of the standard, which will continue to evolve well past September 2018, as will 5G.
Identifying the new architectures necessary is only part of 5G’s evolutionary path. There will be a significant need to test the data plan with an emphasis on throughput efficiency and latency. Additionally, test solutions will need to be built on flexible, scalable platforms that integrate expanded capabilities as needs change and standards advance will ensure next-generation networks perform according to their specifications. Given the structured deployment as per the operators roadmap, 5G may, in fact, end up as a set of parallel deployments and service offerings, sharing some technologies but differing widely in others. With the new development brought about by this technology, 5G will create a strongly competitive business environment across multiple industries. But it can only be built with the right skills and, as a result, many strong engineers, technicians and 5G-Known engineers could find themselves being in very high demand over the next few years.