5G: New Answers, New Questions


Jim Zik is the Vice President for PCTEL RF Test and Measurement Tools Product Management. His responsibilities include PCTEL’s flex scanning receivers, SeeHawk® data collection software, SeeHawk Engage™ test mobiles, and SeeWave® interference hunting tool. Jim continues to work with mobile operators, infrastructure equipment manufacturers, and 5G chip vendors to understand the market drivers, product needs, and rollout schedules for 5G networks.


Joe: What do you consider 5G?

Jim: 5G is the next generation cellular wireless specifications being defined by 3GPP. It really is defined by transmissions in millimeter wave bands, sub-6 GHz bands, broad channel bandwidths – typically 100 MHz or greater, high data throughput, low latency, and advanced beam steering techniques. All of these results in gigabit data rate user experiences.

Joe: As PCTEL’s own engineering team dives into 5G and what it will mean for PCTEL’s network testing solutions, you’ve been meeting with various stakeholders. Has momentum finally come around that will transition 5G talk to real action? What is the timeframe for commercial deployment?

Jim: It’s interesting collaborating with industry experts to understand what 5G is and what it will be used for. There is still a lot of marketing hype regarding 5G, mainly from the manufacturers of 5G equipment to promote a new generation network, but there is also real action. For example there are numerous trials going on around the world with intentions to deploy a pre-5G networks as early as Q1 of 2018 for the South Korean Winter Olympics, even before the 3GPP specification is completed. My objective is to understand the market driver for 5G and how PCTEL can best address this new mobile technology from a field test equipment perspective.

Joe: What is the market need?

Jim: The market driver of 5G is to provide a low cost, low latency, high-capacity, reliable network for mission critical IoT applications. Virtual reality, augmented reality, virtual presence, and massive machine-to-machine type communication, are just a few of the numerous nascent applications. 5G networks could eventually lead to creating intelligent neural networks to manage cities, factories, traffic flow for driverless cars, and countless other data driven activities all managed by humans today. 5G has the potential for powerful societal benefits.

Joe: People reading this may think “that’s great, but there needs to be worldwide specifications before anything really gets done”.  What is the status of a 5G specification today?

Jim: There are various approaches. The pre-5G Verizon forum specification; pre-5G Trial Services for the Korean Winter Olympics,  phase 1 of the 3GPP 5G non-standalone New Radio (NR); and phase 2 of the 3GPP 5G NR. The immaturity of the 3GPP specifications led to the creation of the Verizon forum to get a head start on 5G. The Verizon forum has developed a pre-5G specification, separate from 3GPP that involves about a half dozen operators around the world. It is a fixed wireless access specification in the millimeter bands that does not involve any mobility. The pre-5G Trial Services for the Korean Winter Olympic Games involve mobility using 4G LTE as the anchor carrier.

During Mobile World Congress 2017 last February, a consortium of companies announced a new phase of the 3GPP-based 5G specification called the non-standalone radio to speed up the 3GPP specifications for enhanced mobile broadband and ultra-reliable low latency communications. It employs a standard 4G network as the primary radio carrier, and then adds 5G secondary carriers to increase capacity using a carrier aggregation approach. So operators can use existing infrastructure for part of the network and evolve their networks to 5G. Many carriers are expected to use this technology to for fixed wireless access services. The non-standalone 5G NR specification is expected to be available in the end of 2017.

Last, is phase 2 of the 5G new radio specification which defines a completely new radio access network with new infrastructure that has 5G primary and secondary carriers, with mobility expected to be the main use case. This new 5G new radio specification could be finalized as early as December 2018. In addition to enhanced mobile broadband and ultra-reliable low latency communications, phase 2 also support massive machine-type communications.

Joe: So 3GPPis moving forward with non-standalone 5G new radio specification and the 5G new radio standard?

Jim: The non-standalone 5G new radio specification is an intermediate variant of the 3GPP 5G new radio specification. Or you can think of it as the first phase of the 5G new radio, but not its own specification.   It boils down to use cases. Operators are finding it difficult to justify the expense of a brand new 5G network without understanding what applications that will drive business and residential customers to fund a new network. With the non-standalone 5G new radio they can employ their current investment in their 4G LTE networks. Lessons from the dotcom bubble that burst in early 2000s are still in mind, carriers need to protect their return on investment.

Fixed wireless access is the first use case that seems to have potential for economic value. Major operators in the U.S. want to lower the cost of delivering broadband to the enterprise and residential customer. After a decade of laying fiber to the home, less than 10% of America is covered, and that happened mainly in high density regions in the Northeast and Mid-Atlantic. The vision of the mobile operators now is to bring fiber to the curb by placing a 5G base station at the curb and then to beam mm-band radio waves, typically defined in the 30 GHz range, to the user’s  5G customer premise equipment. This could provide high capacity services.

Joe: Which would be at much lower cost than fiber to the individual home or enterprise customer?

Jim: Yes, initial studies have shown this to be much lower cost than fiber to the home. A single fixed wireless access 5G base station might service 32 to 64 residences or enterprises. Conversely, the business case for mobility is less clear. Given the range of several hundred meters and directionality of mm-band radio waves, the use cases for 5G mobility may be more limited

Joe: What radio bands will 5G employ? You mentioned mm-band.

Jim: 5G can be deployed in both the traditional cellular sub 6 GHz bands used by 2G, 3G, and 4G networks today, or in the mm-band. The mm-band is useful to obtain high capacity multi-gigabit speeds. The major difference between 4G LTE and 5G for sub-6 GHz frequencies is the low latency 5G frame. The FCC approved licensing for mm-bands 28, 37, and 39 GHz, with the 64 to 71 GHz range available as an unlicensed band. Europe is leaning towards licensing the 24 GHz mm-band in the future. It’s worth noting some US carriers own spectrum in the 15 GHz frequency range.

Joe: How will limited range and directionality of mm band frequencies affect the usability of 5G involving mobility?

Jim: It depends on the location. In very dense hot spots there could be a business case for mobility. Several hundred meters may seem like a lot of coverage, but mm-band is a line-of-sight frequency, so when a sign, a tree, a street pole or even the user blocks the 5G mm band signal near line-of-sight the throughput can drop by a factor of 10 or 100. Distance and lack of line-of-sight could be limiting factors since it’s unclear how well mm-band wavelength will reflect.

Joe: The user themselves disrupting the line-of-sight to the device they’re holding to the point it hinders throughput is a problem to say the least.

Jim: Right. mm-Waves – which are essentially microwaves – are very directional. They can reflect off smooth surfaces like windows or some walls, but it’s unclear if it can be effectively relied upon for high throughput when there is no direct line-of-sight. In addition, given the small size of the mm-wave, tracking the user with beam steering technology may be a problem if the user is moving faster than typical walking speeds.

Joe: Given all the limitations of mm-band waves, how will fixed wireless access points and mobile devices be able to acquire the 5G signal?

Jim: The 3GPP 5G standard’s body is talking about 5G pilot signals sent out in repetitive beamformed patterns through time and space that the user device will be able to lock to. Once that happens, beamforming is employed by the base station antenna to steer the beam directly to the user device which then can deliver high capacity throughput. This technique can be utilized for both fixed wireless access and mobility. However, it is still unknown how reliable mm-band beam steering will perform with mobile user devices in real-world environments.

Joe: When do you expect rollout of fixed wireless access and mobile 5G networks?

Jim: I see fixed wireless 5G networks being deployed as early as late 2018. I believe mobility is several years away in the early 2020s, given all the technical challenges that still need to be resolved.

Joe: All right, predictions and marketing hype aside, what is PCTEL actually working on right now ahead of 5G network deployment?

Jim: We have already committed resources to research to better understand the characteristics of mm-band propagation and the key factors likely to be included in the ultimate 5G specifications. Our testing solutions will evolve to provide power measurements and mapping functionality in the 5G spectrum. From there we will work to add the ability to decode the pilot signals to be able to characterize and provide coverage maps.

Joe: This has been very informative. Thank you for your insight.

Jim: Thank you. It’s been a pleasure. I believe this is a very exciting time for cellular and wireless networks with the best yet to come. The future is indeed bright with the possibilities that 5G provides.

Contact scanners@pctel.com for any current 4G network testing solutions needed, or to start a conversation about the road ahead to 5G.