Telstra's plan for 'wedding cake' 4G coverage
A Telstra and Ericsson trial of LTE Advance carrier aggregation technology that achieved 450Mbps download speeds will ensure the company keeps up with demand for mobile data.
Telstra worked with Ericsson to install production hardware into its existing mobile network and ran the trial over its backhaul and existing core network. In the trial, Telstra combined two, 20MHz, 2600MHz spectrum channels for Frequency Division Duplex LTE, and the company's existing FDD LTE network operating in the 1800MHz spectrum band with prototype simulator Cat 9 devices to achieve the speeds.
"For all intents and purposes, we were simulating a commercial configuration to get those types of peak speeds in our networks," Telstra's group managing director of networks, Mike Wright told ZDNet.
He said that combining the spectrum bands together will make the use of the spectrum more efficient, and would improve the throughput at each cell site to cope with the rising demands for mobile data.
"This is a forward-looking trial and view to ensure we have the tools in our toolbox to deal with the ongoing explosion of data demand on our networks," he said.
While Telstra has tested it in the 1800MHz and 2600MHz spectrum bands, Wright said that Telstra would end up using spectrum across three bands: 700MHz, 1800MHz, and 2600MHz.
"Ultimately for capacity, the spectrum band doesn't matter that much, but for performance you want the lower band to get you to the edge of the cell," he said.
"You'll get a wedding cake of cell coverage. So when you're in close to the cell you'll be able to use the full speed, and as you work your way towards the edge of the cell, you've got yourself back to the lower frequencies. So you get the best of both coverage and performance by combining those spectrums.
"This is an architecture that's really suited to the Australian environment where we want to cover longer distances and get further into buildings."
Telstra's test across three channels was slower than a trial conducted by Optus late last year with Huawei using four 20MHz channels in the 2300MHz band using time-division duplex LTE technology. In that trial, Optus was able to reach 520Mbps download speeds.