Challenges with 5G

5G is poised to revolutionize our digital existence, but it’s going to be a long road. There are many challenges to a fully-realized, extended 5G network. Let’s look at some of the major challenges the industry faces, along with how the major carriers are positioning themselves to get nice, juicy pieces of the 5G pie.

Why 5G?

For some nice background, take a look at our earlier blog, 5G – What is it and how does it compare to 4G LTE? Here, we discussed the main advantages of 5G over current wireless specs, namely, significant improvements in:

• Bandwidth – 5G should provide approximately 10-20x improvement in the amount of data that can be moved around wirelessly, peaking at around 10-20 Gbps versus the current upper limit of 4G LTE of around 1 Gbps.
• Latency – 5G should provide much more responsive communications, with typical latencies of around 1 ms – a solid 50x improvement over current typical latencies of around 50 ms.
• Number of devices supported – The 5G networks of the (near?) future should be able to connect and handle the traffic of approximately 10x the number of devices that current wireless networks support – about 1 million devices per square kilometers versus about 100,000 in today’s networks.

5G Technology Challenges

But there are significant technological challenges in realizing 5G networks. More detail can be found in our earlier blog, but a quick summary is:

• Frequency Spectrum – 5G is currently slotted to use 24 GHz – 52 GHz as well as 64 GHz – 82 GHz, while 4G LTE currently uses 600 MHz – 2.5 GHz. The higher frequencies are in the mm-wave (mmWave) region of the spectrum, and while these frequencies can carry more information with less latency, their range is much shorter than current 4G networks, and you generally need line-of-sight between your 5G device and any cell tower/base station. These mmWave also do not propagate through windows or walls and rain and snow can also severely disrupt transmission.
• Small Cells – Due to the shorter ranges that mmWaves can travel, the large, relatively high power cell stations of current wireless networks will need to be replaced with many smaller, lower-power base stations and towers.
• Massive MIMO and Macro Cells – Each 5G mmWave antenna will operate using MIMO – multiple input, multiple output technology which will allow them to transmit and receive more data simultaneously than current 4G antennas. And since the antennas themselves will be much smaller, 5G towers will consist of many more antennas (up to 100) per base station.
• Beamforming – Another unique aspect of 5G will be beamforming. The 5G macro cells will have an operational mode somewhat like a phased-array radar – multiple antenna elements can be combined together using advanced signal processing techniques to “steer” the radio signal in a desired direction. This essentially allows you to operate the macro cell as a collection of many high-gain antennas, with improved SNR (signal-to-noise ratio) for the end user.
• Full Duplex – 5G antennas will utilize full-duplex communications, where a single antenna can both transmit and receive information at the same time. Current 4G antennas use half-duplex communications so that separate physical antennas are responsible for transmission and reception (at slightly different frequencies).

Major Decisions for Carriers

So, while 5G sounds awesome, and promises to revolutionize our lives by enabling super-fast consumer internet, autonomous and intelligent vehicles and highways (in particular, the reduced latency is critical here), the Internet of Things (IoT), smart buildings and cities, highly advanced augmented and virtual reality applications, and many other use cases we have yet to imagine, there are significant challenges moving forward. Fully realized 5G networks are certainly still at least several years away – and we should prepare ourselves for the onslaught of confusing 5G nomenclature, as carriers brand early versions of 5G as everything from 4.9G and 5G Lite to 5G Plus and 5G E. As 5G networks continue to come online, they will rely heavily on the existing 4G LTE infrastructure to bridge the two technologies, and gain confidence and competence with the intricacies of implementing 5G technology.

5G networks will also significantly leverage 4G spectrum and infrastructure as the technology develops. They will likely continue to utilize 3 separate sub-bands: A low-frequency band for more coverage area (sub 1GHz), a mid-frequency band for a better blend of coverage range and speed (1-6 GHz), and the high-frequency band, including mmWaves, for maximum bandwidth and throughput (above 6 GHz). When using the lower frequency bands, most carriers will share the bandwidth with the 4G LTE network, and use a technology called DSS (Dynamic Spectrum Sharing) to switch between the two networks when 5G coverage drops out.

A Bit More on mmWave vs Sub-6 5G

One of the key decision’s carriers must make is how much to invest, and how soon, on the real gamechanger of which frequency bands to use in their 5G buildout. There now exists an arbitrary, but fundamental dividing line between mmWaves and non-mmWaves implementation. mmWaves officially occupy the 30-300 GHz frequency range, but in terms of 5G rollout, the dividing line has been set at 6 GHz. Frequencies above 6 GHz are considered to be mmWave, while frequencies below 6 GHz, also known as sub-6 GHz, are the longer wavelengths currently used in wireless communications.

The importance of mmWaves to the long-term 5G landscape cannot be overstated. It is only at these very small wavelengths that you get the huge performance benefits in bandwidth, latency, and device density over current 4G LTE networks. But this is also where significant technological challenges still exist, as stated above. Among the myriad of challenges to overcome in order to use mmWave in large-scale 5G deployment, one of the more interesting is the change required in the most basic of hardware components, IC packages and modules, particularly the transceiver module, for smartphones and other systems.

A very informative and detailed discussion of these challenges is presented by Semiconductor Engineering. In particular, they discuss the fact that current smartphones have a dedicated RF front-end module, that handles the amplification and filtering of the antenna signal, but the antenna itself does not reside in the same hardware module. 5G mmWave technology requires the antenna to be co-located in the same module. In fact, the industry is also developing new IC packages which combine the RF chip and the antenna in the same unit, known as “antenna-in-package”.

Integrating the mmWave antenna into the RF module or package is required to boost the signal strength and reduce losses in the system. There are many other challenges as well, such as developing the test tools and equipment necessary to do component testing and larger-scale system testing on these new mmWave platforms. For more information please see Semiconductor Engineering’s article “Challenges Grow for 5G Packages and Modules.”

How the Major U.S. Carriers are Rolling Out Their 5G Networks

The huge choice that every wireless carrier faces when it comes to rolling out their 5G networks is how they want to utilize the different frequency spectra available to them. As we discussed, there are basically three options, and all the carriers use some combination of these bands:

• Low Frequency Band– Below 1 GHz. Great for coverage, not so great for speed or latency
• Mid Frequency Band – Between 1-6 GHz. Nice blend of coverage and performance
• High Frequency Band or mmWave – Above 6 GHz. Lousy coverage, great potential for speed and low latency

All 3 major U.S. carriers are providing some kind of 5G to their customers but as discussed earlier, this can mean vastly different performance, and it is far from trivial to figure out exactly what the performance is for each carrier. A couple of nice articles from Opensignal summarize 5G performance and availability for leading providers and also by country. The performance numbers are several months old, and the 5G map changes rapidly, so expect these number to also change.

• AT&T
  • Their Hype
    • “Now the fastest nationwide 5G network”
    • “AT&T 5G reaches over 225 million Americans, in more than 14,000 cities and towns”
    • “Fast, reliable, and secure”
  • The Facts
    • Using Frequency bands n5 (850 MHz), and n260 (39 GHz)
    • Offers some mmWave networks as “5G Plus”, but coverage is extremely limited but with good performance
    • Offers a generic “5G” plan that operates on lower-band (850 MHz) along with 4G LTE. Coverage is extensive, but performance is a bit better than 4G LTE
    • 5G download speeds average about 2x their 4G speeds (63 Mbps vs 33 Mbps)
    • 5G availability is around 10%

• T-Mobile/Sprint
  • Their Hype
    • “We are America’s largest 5G network – covering over 8,300 cities and towns. That’s more than twice the 5G coverage of Verizon or AT&T. And now that Sprint is part of T-Mobile, we’re bringing more of the fastest 5G to more places than anyone else.”
    • “To bring you speeds as fast as Wi-Fi, we’re upgrading over 1,000 cell sites & towers each month with high-performance, Ultra Capacity 5G—to cover not just parts of some cities—but entire metropolitan areas.”
    • “Broader coverage, faster speeds (2x that of 4G LTE), greater signal strength.”
  • The Facts
    • Using Frequency bands n71 (600 MHz), n41 (2.5 GHz), n260 (39 GHz), and n261 (28 GHz)
    • T-Mobile also offers some mmWave coverage as well as extensive low-band coverage at 600 MHz.
    • The merger between T-Mobile and Sprint has allowed T-Mobile to also leverage Sprint’s mid-band frequencies to provide pretty good coverage with markedly better performance than 4G LTE.
    • 5G download speeds average about 4x their 4G speeds (114 Mbps vs 26 Mbps)
    • 5G availability is around 20%

• Verizon
  • Their Hype
    • “Now with the coverage of 5G Nationwide for 200+ million people in 1800+ cities and the unprecedented performance of 5G Ultra Wideband in select parts of 60+ cities”
    • “The fastest 5G in the world. 25x faster that today’s 4G networks.”
  • The Facts
    • Using Frequency bands n5 (850 MHz) and n261 (28 GHz)
    • Has been the most pro-active building out a truly mmWave network. The speeds are blazingly fast, but coverage is severely limited to certain parts of certain cities – sometimes even only available over a few city blocks. They refer to this as Ultra-Wideband 5G, or 5G UW.
    • They also offer “5G Nationwide” which uses sub-6 GHz frequency bands. Their coverage is extensive, but the performance is comparable to 4G LTE.
    • 5G UW download speeds average about 18x their 4G speeds (506 Mbps vs 27 Mbps)
    • 5G UW availability is around 1%

Keep Your Eyes on the Frequency Bands Moving Forward

As 5G continues to spread its wings and improve coverage and performance, it’s important to pay attention to exactly what the providers are offering in your area. True 5G performance is only available if they are using mmWave technology, but coverage will continue to be quite limited for some time. Low frequency bands will provide 4G-like coverage with a small-to-modest performance boost when using 5G. The mid frequency bands will provide decent coverage along with a decent performance boost over 4G.

And keep an eye on upcoming frequency spectrum auctions by the FCC. While the government still controls the majority of the mmWave spectrum, they have already started auctioning off various bands. These auctions will continue as the carriers build out their networks.

Rob Stone, Mushroom Networks, Inc. 

Mushroom Networks is the provider of Broadband Bonding appliances that put your networks on auto-pilot. Application flows are intelligently routed around network problems such as latency, jitter and packet loss. Network problems are solved even before you can notice.

https://www.mushroomnetworks.com