5G is truly a global phenomenon, and 5G NR – the global 5G standard – is being designed to support all spectrum types and bands for global deployments starting in 2019. We recently sat down with Dean Brenner, SVP of Spectrum Strategy & Tech Policy at Qualcomm Incorporated, to discuss 5G spectrum for China with the emphasis on TDD spectrum utilization.
1. How do you evaluate the technical advantages of TDD spectrums towards 5G evolution? What requirements does 5G have on spectrum?
In recent years, unpaired spectrum suitable for TDD has become increasingly important to unlock more capacity for our mobile networks. In general, unpaired spectrum bands—typically called TDD spectrum—generally exist in higher frequencies, such as 2.5 GHz and higher, including the so-called millimeter wave (mmW) bands, at 24 GHz and higher. These bands offer wider bandwidth than the lower paired bands, which are typically the FDD bands.
For 5G, to achieve the superior performance to enable enhanced mobile broadband, massive Internet of Things, and ultra-low latency, ultra-reliable communications, which are the use cases that the global 5G standard known as 5G NR will support, it will be designed to enable use of for all spectrum bands (low – sub-1 GHz, mid – 1 GHz to 6 GHz, high – 24 GHz and beyond in the mmW bands) and types (licensed, shared, unlicensed), in both FDD and TDD bands.
TDD spectrum will have a very important role in 5G NR, particularly because many key 5G NR inventions such as self-contained subframes, are designed to make TDD spectrum more capable and efficient. The benefits of these innovation include faster transmit and receive, and lower latency and efficient feedback for massive-MIMO—a key technology to make the higher spectrum bands viable for mobile applications. Another key 5G NR invention for TDD spectrum is dynamic uplink/downlink, in which the network capacity can be optimized dynamically according to real-time traffic patterns and requirements. For all of these reasons, we view TDD spectrum as vitally important for 5G.
2. 5G should balance high frequency bands for data transmission and low frequency bands for coverage. From your perspective, how should we allocate the frequency bands to better meet the industry requirements?
5G NR is being designed for all spectrum bands—low to high—but the more immediate spectrum opportunity in most regions is the opportunity to take advantage of higher spectrum bands, including the frequencies around 3 GHz in the sub-6 GHz range, and above 24 GHz, where so much more bandwidth is available than in lower bands. Another important aspect of 5G that should be considered in terms of spectrum is the rollout of Gigabit LTE, which is underway in China and around the world today. Gigabit LTE is important both in its own right, to provide better, faster mobile broadband today to consumers, but also to complement 5G. The rollout of 5G will take a considerable amount of time and will start in dense urban areas. As consumers leave 5G coverage, it’s important that they continue to have access to very fast, high quality mobile broadband. That’s what Gigabit LTE will provide.
5G will use the mid-band, sub-6 GHz spectrum to expand the Gigabit LTE footprint for wide area coverage. Moreover, 5G will use mmW spectrum to deliver multi-gigabit mobile broadband in high-density areas—high density by population or high density in terms of necessary capacity.
Finally, we envision lower bands (sub-1 GHz) being used in some cases for LTE as is the case today, but also in some regions such as the US and Europe, we envision some 5G NR deployments in the 600/700 MHz bands. Eventually, as it proliferates, 5G NR will be deployed in the lower bands globally to establish the coverage foundation for new 5G services. This will be especially important for massive IoT applications, which require wide-area coverage, but are not as demanding in capacity.
3. The sub-6 GHz bands at 3400-3800 MHz are expected to be mainly used for 5G deployment in Europe before 2020. Do you think the 3400-3800 MHz bands will also play a vital role in China’s future 5G deployment?
Yes, absolutely. We see the 3400-3800 MHz band as an important 5G band for China and in other regions around the world, not only Europe. We also see many other regions, such as US, Canada, South Korea, Australia, targeting or have already allocated this spectrum band for 5G. In China, we currently see 3.3-3.6 GHz targeted for 5G, and this further reinforces the importance of frequencies in the 3 GHz range for 5G across the globe.
4. Wide bandwidths are available above 6 GHz, and the availability is different from country to country. In your opinion, what frequency bands are more applicable for 5G? Globally speaking, how are these bands allocated? Additionally, which frequency bands are more suitable for 5G deployment in China?
We see mobilizing mmWave bands as being absolutely essential to 5G. It will deliver extreme bandwidth that is essential to meet the requirements to provide much better, faster, enhanced mobile broadband and to provide a significant differentiation compared to the Gigabit LTE service available today in China and elsewhere around the world.
And just as we are seeing a global opportunity in the 3 GHz range for sub-6 GHz deployments, we see many countries across the globe allocating or planning to allocate mmW spectrum—the bands above 24 GHz. In July 2016, over a year ago, the US allocated 11 GHz of mmW spectrum—a large amount of spectrum—for 5G. Other regions, including Europe, Korea, Japan, Australia, Canada and more, are also in the process of allocating mmW spectrum for 5G. In some cases, a portion of this spectrum may be allocated as shared or unlicensed, rather than licensed, as may be necessary due to particular situations.
There is no doubt that mmW spectrum is essential for 5G in China and around the world. In China, the focus is on the range from 24.75-27.5 GHz, as well as 37-42.5 GHz. Importantly, these bands overlap with bands that have been allocated or targeted in whole or in part around the world. For example, in 2016, the US allocated 37-40 GHz and sought additional comment on allocating 42-42.5 GHz and 24.25-24.45 GHz and 24.75-25.25 GHz. Europe is also targeting 24.25-27.5 GHz as a pioneer band. Korea, Japan, Australia, and Canada are all focusing on various mmW bands.
5. Could you share with us what progress you have made for tests and trials of 5G spectrums and technologies? Do you have any suggestion on 5G spectrum planning?
Qualcomm has already conducted significant 5G NR testing and trials in both sub- 6 GHz and mmW bands. We are working to mobilize the smartphone in both of these ranges to enable the commercial launches of 5G NR to start in 2019. We have developed and demonstrated trial platforms that utilize these frequency ranges, and we have announced our first 5G NR modem family – the Snapdragon X50. The X50 will support 5G NR in both sub-6 GHz and mmWave ranges. In addition to the spectrum in the 3 GHz range already discussed, another sub-6 GHz bands that Qualcomm will be supporting for 5G NR is Band 41, the TDD 2.5 GHz band. Qualcomm is working with Sprint and SoftBank to commercialize Band 41 for 5G NR to enable service to launch in late 2019.
We are also working on new techniques of spectrum sharing to incorporate into a version of 5G NR known as 5G NR SS (shared spectrum). It will ensure that 5G NR can achieve the greatest possible efficiency across all spectrum types— licensed, shared, and unlicensed. And just to reiterate, I believe every region should plan for 5G NR deployments in both sub-6 and mmW spectrum so the full benefits of 5G can be realized.
6. From your perspective, how will the unified 5G TDD spectrum influence the industry chain? For example, how will it impact the antenna systems?
From our point of view, as a chipset provider, we always prefer and advocate for the greatest degree of harmonization possible across countries and regions in terms of spectrum. Harmonization of spectrum creates economies of scale that result in lower costs. We always know, nevertheless, that complete global harmonization is rarely possible, and as a result, in 4G, we support as many different frequency bands and band combinations as possible. For 5G, we are supporting both sub-6 GHz and mmW ranges, and we’re very pleased that as noted above, there is good harmonization in China and around the world on the frequency ranges under consideration for allocation or already allocated.
Device designs for 5G TDD spectrum will require new capabilitiesin all components of the physical layer, including the modem, RF transceiver, the complete RF front end, and even antennas. Antenna design is already evolving to support wide frequency ranges from low sub-1 GHz bands to 6 GHz for sub-6 GHz operation while being software-tunable. In the mmWave spectrum, array-based antennas are expected to support beamforming and beam-steering for high throughput and bandwidths in challenging mobile form-factors.
7. What are the opportunities and challenges facing the industry in regard to unifying the 5G TDD spectrum? Will it lower the costs for chipset design?
As noted above, we always prefer and advocate for the greatest degree of harmonization possible across countries and regions in terms of spectrum. Harmonization of spectrum creates economies of scale that result in lower costs for chipset design. Total global harmonization is usually not possible, which is why we support as many bands and band combinations as possible. For 5G, China is targeting frequency bands in both the sub-6 GHz and mmW ranges that line up well with bands that have been allocated or targeted in other regions and countries around the world. We hope that China allocates its sub-6 GHz and mmW spectrum as soon as possible, and we look forward to working with our many partners in China to support the launch of 5G NR in China.
Another very important benefit of spectrum harmonization is enabling global roaming, which has been important for 3G and 4G and will be even more important as 5G rolls out. The harmonization in the mmW spectrum under consideration in China with the US (37-40 GHz initially and 24.75-27.5 and 42-42.5 GHz later), Europe and elsewhere creates exciting, important opportunities to support global roaming for 5G devices sold in China and sold by Chinese vendors for global export.
8. With Rel-15 for 5G to be frozen in 2018, how does Qualcomm address the challenges of 5G standard implementation?
Working with our many partners in China and around the world, we have been a driving force in the standardization of 5G NR Rel-15 from the very beginning. And much of our efforts are focused on ensuring that the output of the standard can be implemented rapidly and cost-effectively in smartphones and other devices. Addressing these challenges early on is essential to ensure that 5G NR launches commercially beginning in 2019.
As a result, we have been working on our 5G NR prototypes as the standards process progresses, and we are using the results of testing that we have conducted with the prototypes to provide input to the standards process. This helps us and our many partners in China and around the world to identify and resolve issues as early as possible. The testing efforts include interoperability device testing (IoDT) in which we work with our partners to make sure that the devices and networks can work together across configurations and vendors. We are extremely excited about 5G NR Rel-15 and are working very hard to ensure that it launches commercially starting in 2019.
