Optus has announced completing Massive Multiple-Input Multiple-Output (MIMO) trials, telling ZDNet that in a world first, it combined the Massive MIMO technology with three-cell carrier (3CC) aggregation to attain combined throughput of 818Mbps.
Kent Wu, director of Mobile Networks Planning at Optus, told ZDNet that the trials were conducted across its live network in Macquarie Park, Sydney, increasing the capacity of the network fourfold.
"We have combined three-cell carrier aggregation together with the Massive MIMO, so now it's live in the network," Wu said.
"We have taken this technology one step ahead, and by using the two technologies combined together, we are the world's first to enable this three-cell carrier aggregation and Massive MIMO in the live network."
The trials, which commenced in June, were conducted alongside Chinese networking giant Huawei, Wu told ZDNet.
"We worked with Huawei again because we have started off earlier this year with Huawei on the Massive MIMO, and they are the industry leader in terms of this technology," Wu explained.
"So we continued our strategy and worked with Huawei by using their hardware equipment and software to enable this."
Optus used a 64T64R antenna system for the trials across its time-division duplex (TDD) 2300MHz spectrum band, with Wu explaining that Optus is the only mobile operator currently running TDD at 2300MHz in Australia's cities.
The 2300MHz band will also allow it to extend carrier aggregation to 4CC in future, with Wu saying that Optus is additionally considering trialling Massive MIMO on frequency-division duplex (FDD) spectrum on the 1800MHz band in future.
Optus and Huawei also made use of beam-forming technology during the trial, which he said improves accuracy and gives the multiplexing and spatial diversity needed to improve user experience in terms of capacity and congestion.
As part of its previously announced 4.5G expansion, Optus will begin deploying its 3CC-Massive MIMO technology across its 4G networks in capital cities starting from the end of 2017, predominantly in Sydney and Melbourne, as well as using it for special events.
"Because this technology works very well for special events and crowded locations, we are getting ready for that, for example catering for New Year's Eve events, and for example the big events coming up in the beginning of the year like the Australian Open tennis," Wu told ZDNet.
Importantly, Wu said the trials show that using new networking technology, Optus can make use of its existing spectrum holdings to provide greater capacity, as well as the technology being a precursor for 5G.
"Optus has been at the forefront in the 5G technology development, and also to adapt some of these fundamental 5G technologies to the 4.5G use," Wu said, calling it a "significant milestone for us in the way of leading to 5G".
Wu said Optus is continuing to test 5G with several vendors, including Huawei and Nokia, having attained speeds of 35Gbps in a 5G network trial with the former back in November 2016.
The 5G trial was conducted over the 73GHz millimetre-wave (mmWave) spectrum band, using the Polar Code coding mechanism.
Optus last year also signed a memorandum of understanding with Nokia to collaborate on developing its 5G network, under which it has undertaken closed lab tests using Nokia's 5G radio test bed on its Airscale product, as well as narrowband Internet of Things (NB-IoT) tests.