High Order MIMO Moves Center Stage in Wireless Networks

MIMO innovation holds out the promise of higher-capacity 4G and 5G networks, as well as lowering MNO costs.

Ken Wieland, contributing editor

July 8, 2021

6 Min Read
High Order MIMO Moves Center Stage in Wireless Networks

The Wireless Foundation Summit, held at Mobile World Congress, shone the spotlight on how mobile network operators (MNOs) can maximize the value of their networks and existing spectrum assets in a cost-efficient way.

Moderated by Peter Jarich, Head of GSMA Intelligence, the Wireless Foundation Summit welcomed MNO input from Beeline (Russia), Celcom (Malaysia), China Telecom and Globe Telecom (Philippines).

An update on 5G 3GPP standards progress was provided by Adrian Scrase, CTO of ETSI, while high order MIMO innovation surrounding both LTE and 5G was on display from Huawei.

Figure 1:

Bocar Ba, commissioner at the UN Broadband Commission, a public-private partnership promoting digital inclusion, kicked off the series of presentations. He was keen to place the summit in the context of wider, socio-economic concerns. “What we’re discussing today has a direct correlation with the speed of advancement of the digital economy,” he said. “Broadband connections should be reliable, universal, and excellent.”

Topics at the summit centred on enabling new services for industry verticals and consumers, as well as improving end-user broadband experiences through higher capacity networks. An additional challenge, noted by all speakers, was huge jumps in data usage as more people — because of pandemic-induced lockdown measures — work and study from home.

CS Yap, chief network officer at Celcom, spoke repeatedly of the “new traffic norm.” Since the onset of the pandemic in early 2020, the Malaysian MNO has seen a 70% increase in data consumption, with demand shifting markedly from commercial to residential areas.

Putting in place a robust, foundational wireless network layer, involving both 4G and 5G, was understandably seen as key to ensuring improved end-user experiences and extending coverage. Clever use of low-band, mid-band, and high-band spectrum — on the back of ‘smart’ multiple-input, multiple-output (MIMO) antenna configurations and massive MIMO — was a recurring (and welcome) theme at the summit. Squeezing the most out of finite and existing spectrum assets was seen as a must, as was leveraging LTE to complement 5G.

Ed Gubbins, principal analyst at Global Data, a research firm, highlighted that massive MIMO and beamforming were important for “maximising spectrum 5G efficiency in the 5G era.” 8T8R, along with massive MIMO, he added, could also be usefully deployed in mid-band FDD spectrum (sub-3GHz) to achieve higher capacity. Low-band 4T4R, said Gubbins, was ideal for broad, universal coverage.

MIMO innovation roadmap

ETSI’s Scrase highlighted recent enhancements in MIMO standards, most notably 3GPP Release 16, which introduced enhanced Type II codebook with DFT-based compression and support for multi-TRP transmission.

“Standards-wise, MIMO is not new,” said Scrase. “What is new is that we’re actually beginning to see MIMO deployments and lessons are being learned. We’re understanding some of the complexities of using MIMO, both above and below 6GHz, particularly when you might have user equipment moving at great speed and need very low latency within the MIMO system.” The lessons learned, as Scrase puts it, will feed into Release 17 and Release 18.

A timetable for Release 18 will be set by December 2021. 3GPP brands Release 18 and beyond as 5G-Advanced. “It’s a mid-point stepping-stone between where we are now with 5G and where we’re likely to be in ten years’ time with 6G,” explained Scrase.

Qi Bi, Chief Expert at China Telecom, enthusiastically welcomed the MIMO innovation roadmap. He saw it as vital in easing network capacity bottlenecks and serving various industry sectors with faster data rates. He flagged steel, mining, and ports as key target markets for China Telecom.

“Because of the importance of FDD systems in 5G vertical applications, the availability and performance of FDD handsets are highly anticipated,” said Qi. “Using Release 15 as a baseline, better data rates can be obtained in time with later releases using FDD massive MIMO technology. By using 32T32R massive MIMO, it is estimated that data rates can improve by about 50% using Release 16 handsets, and almost double the data rate when using Release 18 handsets.”

High order MIMO on the ground

Gavin Wu, senior adviser for access engineering and management at Globe Telecom, highlighted deployment of Huawei’s SingleCell+low-band 4T4R solution, which is the first of its kind in the world.

“We’ve seen a huge increase in LTE data traffic since the pandemic, so it’s more important than ever to have deeper indoor penetration coverage and provide a better user experience for subscribers at home,” explained Wu.

With the help of clever algorithms and machine learning, the SingleCell +4T4R solution can shift LTE customers, camping on 700MHz low-band spectrum near the cell, onto mid-band spectrum. The average user throughput gain at the edge of the LTE 700MHz cell increased by over 150% in field tests.

In Malaysia, Celcom has successfully trialled Smart 8T8R, and is now embarking on what it calls “commercial mass deployment.” Yap, speaking at the summit, said Celcom had already deployed an FDD 4T4R solution on 58% of its sites nationwide, and 88% of sites in Kuala Lumper the capital, but said it was still insufficient to cater for increased data demand efficiently. “We needed a new, higher capacity solution due to the new norm traffic demand,” he said.

Keeping costs down was another key consideration. By using one radio for 8T8R, as opposed to two 4T4R radios, Celcom expects to trim power consumption by 16% and cut tower rental fees by a half (while at the same time boosting capacity by nearly 1.8x). Huawei’s software-defined antenna, which is part of the Smart 8T8R solution, allows easy migration from 4G to 5G.

Mohamed Fouad Madkour, Huawei’s VP for marketing and wireless solutions worldwide, said high order MIMO was “center stage when it came to enriching 5G”. Moreover, thanks to innovation and evolving standards, more performance enhancements are reassuringly in the pipeline. He added a note of caution, however, advocating that a “multi-layered” approach was the best way to provide the robust wireless network foundation layer that industry was after.

“The key is how operators get the right equipment that really leverages all the innovations in the standard,” said Madkour. “The starting point, especially in low band, is 4T4R, which is the ubiquitous coverage layer. You then go to 8T8R or massive MIMO in the mid-band, which is the universal capacity layer. When it comes to higher bands, massive MIMO is really the only choice, since it combines a lot of capacity with great customer experience. We call it the extreme experience layer.”

This content is sponsored by Huawei.

Huawei Technologies Co. Ltd

About the Author(s)

Ken Wieland

contributing editor

Ken Wieland has been a telecoms journalist and editor for more than 15 years. That includes an eight-year stint as editor of Telecommunications magazine (international edition), three years as editor of Asian Communications, and nearly two years at Informa Telecoms & Media, specialising in mobile broadband. As a freelance telecoms writer Ken has written various industry reports for The Economist Group.

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