The 5G ecosystem continues to mature with increasing deployment and a rising number of users in all regions. This has resulted in a growing demand for high-quality 5G services, making it imperative for the telecom operator to optimize the use of available spectrum and network resources without compromising network performance. 

Different countries are adopting different approaches to achieve 5G success. For instance, China starts from Time Division Duplex (TDD) while Europe is using Frequency Division Duplex (FDD) New Radio for deploying 5G. Telecom operator strategies are based on the spectrum and resource availability in that region. 

However, several new technologies are now emerging that allow them to maximize the utilization of available spectrum. "There are two crucial ways in which telecom operators can maximize the utilization of the available spectrum. One way to do this is to increase the antenna channels from 32 to 64, and the second is to combine the low, medium, and high-frequency bands to enhance the spectrum efficiency. Whether it is TDD or FDD technologies, we are focusing on these two directions to maximize the efficiency of the existing spectrum," said Fang Xiang, Vice President of 5G and LTE FDD Product Line, Huawei, in an exclusive interview with Total Telecom. 

Addressing the challenges associated with FDD NR 

There is a growing interest in using FDD bands at lower frequencies in combination with mid-bands for quick deployment of 5G. This is especially relevant in markets where the C-band spectrum is not available or in regions where large capacity is not required in the initial phases of 5G. 

Even as there is a growing interest in FDD NR, there are several challenges associated with it. While FDD NR is a powerful technology in terms of coverage, especially indoor coverage, it can be further enhanced to provide the best experience to the users. 

The second challenge is how telecom operators can leverage the FDD NR technology, when they do have high-frequency bands such as C-band, to provide the experience of the next-generation networks based on 4.5G networks to the high-end users in some of the urban areas. 

"Lastly, the third challenge is that the spectrum available for FDD NR is quite narrow and fragmented. In 1.8GHz, it is only 30MHz, and in the 700 and 900MHz, it is only 10MHz. So we need to think of how we can combine the fragmented bands to offer better coverage and a better experience for the users," explains Mr Fang. These challenges can be addressed by Huawei’s ultra-wideband modules, which brings together the spectrum from low-band and mid-band frequencies into a single module for greater efficiencies. 

Growing relevance of the sub-3GHz band 

The use of the sub-3GHz spectrum can mitigate the challenges associated with FDD NR. Telecom operators need the sub-3GHz spectrum to provide a best-in-class mobile broadband experience. 

“5G needs sub-3GHz band to provide better indoor coverage and wide coverage at the network’s edge. We believe it can help operators provide a continuous 5G network. Since it can cover a wide area, it can also reduce the number of sites, which helps reduce the total cost of ownership for the carriers,” explains Mr Fang Xiang. Huawei has introduced sub-3GHz multi-antenna and ultra-wideband solutions that will help accelerate the LTE evolution and enhance 5G performance and coverage. 

Further, a sub-3GHz spectrum is required because 5G technology is not only for enhanced Mobile Broadband (eMBB) use cases but also for Internet of Things (IoT) scenarios. Since it offers deep and wide coverage, it is better suited for IoT deployments. 

“With Massive MIMO [Multiple Input Multiple Output], we can offer better coverage capability with sub-3GHz and C-band when compared with C-band only. For example, after coordinating the sub-3GHz and C-band massive MIMO technology, we can offer better 5G coverage than with C-band only, which means FDD and TDD coordination improves C-band effective user experience (downlink 100 Mbit/s and uplink 5 Mbit/s) by more than 5 dB. And we can offer even bigger bandwidth in the indoor scenario with additional sub-3GHz than with only C-band,” explains Mr Fang Xiang. 

Further, sub-3GHz was part of 2G and 3G networks, deployed about ten years back, and are now approaching the end of the lifecycle. “In the legacy networks, we see problems of deteriorating network quality and problems of network evolution and very high energy consumption. So, if we can continuously involve sub-3GHz in 4G and 5G networks, we can increase the spectrum efficiency and also have better maintenance and bring down OPEX and offer more green networks for the operator,” says Mr Fang Xiang.

More than 860 devices are now able to support the sub-3GHz. While all devices support ED-DC, 70% of the available terminals support the sub-3GHz frequency band. More than 850 terminals support n77, n78, and n79 frequency bands while 775 devices support 2600MHz n38 and n41, according to IDC. Further, 678 of the available devices provide support to 2100MHz n1 and 603 devices support the n3 band. The device’s capability plays a crucial role in ensuring network performance. Higher capability devices lead to better performance. 

New-age innovations, like ultra-wideband and multi-antenna solutions, are critical in low and mid-band frequency bands to provide much-needed high capacity in dense urban locations and improved indoor coverage. Huawei’s FDD Gigaband Modules are helping telecom operators realize the full value of sub-3GHz for 5G success. This was recently validated when it was awarded GSMA’s GLOMO Award for “Best Mobile Network Infrastructure” at the Mobile World Congress 2022. 

“We have split our offerings into three different scenarios. The first is for the rural coverage. We offer a cost-effective 4T4R solution so that our customers can deploy 4G and 5G networks quickly based on our 4T4R solution at a reduced cost. In urban areas, we recommend our 8T8R, which maximizes the network efficiency of 4G and enhances the spectral efficiency of 5G. This solution is also more energy-efficient. On the other hand, we recommend our FDD Massive MIMO solution with improved capacity and better energy efficiency in high traffic areas," says Mr Fang.  

As more and more telecom operators deploy 5G they stand to gain by using FDD NR for an easy and quick transition from 4G to 5G. It also ensures shortest time to market while allowing them to maximize the utilization of available spectrum resources even as they are able to maintain the network performance as traffic continues to grow.