Telstra mulls more LTE trials

Telstra may conduct further Long Term Evolution (LTE) technology trials to follow up three rounds of tests carried out over the past six months, according to its wireless chief.

The telco was one of four Australian carriers to trial LTE – technology touted by networking vendors as being able to cost-effectively support high data volumes on carrier networks at much higher speeds than today's HSPA and WiMAX networks.

Optus, Vodafone Hutchison Australia and vividwireless were also either running or about to commence LTE trials.

Telstra's Wireless networks and access technologies executive director Mike Wright told iTnews the carrier had "largely completed what we set out to do" with its first set of trials.

"At the moment we're assessing the information we got out of them," he said.

"We will consider more testing but it will be informed by what we've learned from the [existing trials] and be in areas we need to understand more about. We're still evaluating our options."

Telstra's Australian engineers would also learn from data fed back from Hong Kong subsidiary CSL, the first operator in Asia to switch on commercial LTE services.

"Our engineers will be able to see the types of results and performance on that network," Wright said.

Commercial deployments?

An investigation by iTnews revealed a broad spectrum of opinions on when LTE would see its first commercial rollouts in Australia and when it would succeed technology used in existing networks.

Huawei's wireless solutions manager Terry Walsh presented the most optimistic assessment: "We'll probably have commercial rollouts starting next year and the year after."

But carrier representatives – including Telstra's Wright and vividwireless chief Martin Mercer – were more cautious.

"It might be working commercially but whether incumbent operators have the spectrum to deploy it prior to the [digital dividend] auctions is another question," Mercer said.

In late-2013, the Government will auction a 126 MHz block of spectrum between 694 MHz and 820 MHz inclusive – dubbed the "digital dividend" because it was being reclaimed from the analogue-to-digital TV switchover.

The most common spectrum bands for LTE were 700 MHz and 2.5/2.6 GHz, although different flavours of LTE could operate in different bands, and Australian telcos were testing those possibilities.

Ericsson A/NZ strategic marketing manager Warren Chaisatien said some operators might "refarm and reuse existing 2G and 3G spectrum" – such as 1800 MHz and 2100 MHz - for LTE deployments "towards the end of 2012 or 2013".

"That can be done before the digital dividend timeline," he said. "It could be done in urban areas where LTE can be deployed to ease capacity [constraints on current networks]."

Telstra's second LTE trial – conducted in June – tested Huawei kit in the 1800 MHz band which, according to the vendor, had "traditionally been used [for] GSM capacity offload".

"The preferred frequency is 700 MHz for rural areas, which is not available until 2013," a Huawei spokesman said.

"In metropolitan areas, 1800 MHz and 2.6 GHz are probably the preferred choices. There's a lot of interest propagation-wise around the trials of 1800 MHz [in Australia]."

Wright said the trial proved that the 1800 MHz band "was viable spectrum for LTE to operate in.

"But the other question to be answered is how mainstream the adoption of that band will be," he said.

"We're not big enough in Australia to set worldwide trends [for spectrum use]."

Read on to page two for Telstra lab test results in the 1800 MHz band and for more details on the other two Telstra LTE trials.

Wright said that in addition to external tests, Telstra had performed lab tests of LTE in the 1800 MHz band, achieving downlink speeds of 149 Mbps and uplink speeds of 59 Mbps.

But he cautioned that "the whole LTE game wasn't about speed" but rather capacity.

"We're doing these trials because we want to understand the next-generation of wireless broadband technology so when we bring it to market we do it in a way that's best for us and for customers," Wright said.

"We also want to be able to architect it for the Australian environment and we have experience doing that in the past.

"We've found technologies are often great for the customer but to suit Australia's environment, its distances and population distribution, you sometimes have to modify its functionality."

Range tests

Telstra's first trials of LTE back in June tested the range of Nokia-Siemens Network kit. The carrier reported pushing average 88.1 Mbps downlink and 29.6 Mbps uplink speeds to the edges of a 75 kilometre cell.

Wright said the trial was run in 2.5 GHz spectrum – a much higher frequency than it would likely use to deploy LTE over long distances.

"We had to compensate for the higher frequency," he said.

But he said spectrum wasn't the most important factor in the test.

"We just wanted to understand whether we could reconfigure LTE to run over those [long] distances," he said.

Wright spoke of Telstra's previous range testing experiences on earlier technologies, including Telstra's initial surprise when it learned of the GSM specification's "inherent 35 kilometre limit."

He also said that the Next G network base stations were capable of operating at a range up to 200 kilometres – a result of the carrier's previous range testing and reconfiguration of networking kit.

Third test

The most recent Australian LTE tests conducted by Telstra used Ericsson kit in the 2.5 GHz band.

It culminated in an intercapital video call between Sydney and Melbourne – although its purpose was really to "look at what it would take to integrate an LTE system into an operating 3G or HSPA network," according to Wright.

Stay tuned to iTnews for part two of our LTE investigation.