We spoke to Yang Xi, President of Huawei’s microwave product line, at this year’s Mobile Broadband Forum event about the ongoing evolution of microwave backhaul solutions and what the future holds for this technology as demand increases
In 2021, 5G is now already well established across much of the world, bringing with it many challenges when it comes to backhaul, not least the greatly increased capacity requirements and device density. Thankfully, microwave backhaul is already proving itself the ideal solution for meeting these challenges in a variety of scenarios and markets around the world.
Indeed, microwave backhaul is currently a mainstay for 4G and 5G backhaul services in many markets and this is unlikely to change any time soon. In fact, the GSMA expects mobile broadband to remain the preferred solution Europe, S&SE Asia, Sub Saharan Africa, Middle East and North Africa, and Latin America and the Caribbean regions moving forward to 2025, despite an increasing predicted uptake of fibre and even satellite backhaul in these areas.
North America and Northeast Asia are somewhat outliers here, currently having a significantly higher reliance on fibre backhaul for existing macro and small cell sites, but even here microwave backhaul is expected to grow in popularity by 2025.
The pandemic has been a major factor in this growth of interest in microwave backhaul. With people forced to stay at home, the demand for bandwidth has grown enormously in the past two years, leaving the industry to rapidly increase network capacity to meet these requirements. Here, microwave backhaul has proved integral to keeping people connected, owing to its simple operation and fast time to market in comparison to fibre.
But despite this growing popularity, microwave solutions are not without their own challenges, especially when it comes to their link range and the cost of hardware for operators.
“The ultralarge bandwidth requirement means greatly increased demands on microwave infrastructure in terms of spectrum and hardware resources, which can quickly lead to an increase in cost of deployment for operators,” explained Yang Xi, President of Huawei’s microwave product line.
For Huawei, improving microwave solutions will be integral to supporting the wider rollout of 5G and creating simpler, more effective solutions will be at the heart of this process.
At this year’s Global Mobile Broadband Forum event in Dubai, Huawei showcased a trio of its latest microwave solutions, aiming at increasing the link range, simplifying its deployment, and making the devices more energy efficient.
A matter of distance
In densely populated urban environments, when it comes to microwave backhaul, the E-band (70–80 GHz) is the principal method of mobile backhaul due to its high capacity. However, E-band solutions are relatively short ranged, and the strong directional quality of the radiation makes the signal subject to deterioration due to environmental conditions like tower sway caused by strong winds, which knock the radio beam off course.
Huawei’s latest solution for the E-band combines high transmission power with signal-stabilising intelligent beam tracking (IBT) tech to realise larger (0.6–1.2 metre) diameter, E-band antenna deployment. The system gain of this solution can deliver, on average, a gain of over 12dB compared to rivals in the industry, as well as increasing the range by around 50%. Ultimately, this means the link can deliver 20 Gbps at a distance increased from 3.5km to 5km.
“This means that all of the 5G sites in an urban area can be served by just one hop of microwave backhaul,” explained Yang.
Meanwhile, in scenarios where distances are slightly greater – in a range of between 7km and 10km – more typical microwave bands (6–38 GHz) are the most popular, due to their greater effective range.
However, in these cases the complex hardware requirements for using multiple channels to meet the high bandwidth demand is the major challenge. Based on the 13, 15, and 18 GHz 4-channel outdoor units (ODUs) launched in 2018, Huawei has now released low-band, 6, 7, and 8 GHz, 4-channel ODUs, covering the mainstream traditional frequency bands. This greatly simplifies the large-bandwidth deployment of more frequency bands. This solution is capable of achieving 10 Gbps at a range of 20 km.
“In these rural kinds of scenarios, the main challenge is the distance. Due to the characteristics of the microwave spectrum, we need to use a combination of low frequency bands to meet the large bandwidth requirements, therefore traditional solutions had to use multiple antennas, which would make the deployment highly complex, with high cost and using a lot of space on the towers. As a result, the engineering costs remain high,” said Yang.
In those long link scenarios, with range requirements of over 20km, the situation becomes even more challenging and complex.
Following their focus on simplicity, Huawei’s solution to this challenge, has been to combine the lower frequency bands (6–8 GHz) into a single piece of hardware, able to deliver 10 Gbps at a range of 40km. This0 solution, called SuperLink can help meet the backhaul requirements for small villages and towns with just a single antenna.
A greener choice
Of course, as the bandwidth demand increases around the world, alongside the growing climate crisis, building a greener, more sustainable network is becoming a major priority for operators.
Here too microwave backhaul is proving itself promising technology, with great potential for dynamic power consumption. By leveraging the latest innovations, like software defined networks and hardware matching, microwave solutions’ power consumption can be adjusted in real time according to the bandwidth requirements. In effect, this radiofrequency hardware can be run in a low-power mode, or even turned off entirely, when they are not needed.
“When the bandwidth requirement is low, we are even able to shut down certain channels,” explained Yang. “This technology should allow us to reduce energy consumption by 20% for these solutions.”
The future evolution of microwave backhaul
As 5G evolves, the demands on network capacity will continue to increase at an incredible speed, begging the question: will microwave backhaul be able to meet the coming boom in demand?
Absolutely, says Yang, who argues that expanding the range of E-band solutions will be a top priority in the years to come, ideally allowing them to be used in the majority of urban scenarios.
“We will develop E band equipment that features larger capacity and multiple channels and make explorations in long range and large capacity microwave technologies,” said Yang. “We’ll be adopting new technologies, like dual channel, in order to meet requirements for large bandwidth and high capacity.”
But this evolution in microwave technology is not only about creating better hardware solutions, it is also about a broader transformation towards a smarter, more efficient network.
For Huawei, this is exemplified by their Network Cloud Engine (NCE) platform, integrating intelligent network management, control, and analysis functions, helping customers to manage their networks in a flexible and more automated way. Ultimately, this will form the foundation upon which greater microwave innovation is delivered.
“In summary, larger capacity, longer reach, and more intelligent management are our directions for the future with respect to microwave,” concluded Yang.
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