Vividwireless trials TD-LTE in Sydney

Vividwireless plans to run a four-week trial of TD-LTE kit in Sydney to understand how it compared to the company's current technology of choice, WiMAX.

The ISP was the only known local test site for Long Term Evolution Time Division Duplex standard, known as TD-LTE.

Other Australian LTE trials – such as Telstra, Optus and VHA – used the more common frequency division duplex (FDD) flavour of LTE.

At least 22 LTE networks were due to be in service worldwide by the end of the year, with another 55 to come online in 2012, according to Ericsson. Most – if not all – would be FDD-based.

But TD-LTE was emerging in parts of Asia and was touted by Ericsson's A/NZ strategic marketing manager Warren Chaisatien as a "very good [future] migration path for WiMAX operators".

Vividwireless chief Martin Mercer told iTnews that the company's decision to trial LTE was "part of [our] continuing technology roadmap assessment.

"WiMAX 802.16m and TD-LTE are basically on a converging path so we want to make sure we understand how TD-LTE compares to WiMAX in an actual operating environment rather than just a lab," Mercer said.

"[But the trial] doesn't suggest any immediate plans to move [away] from WiMAX".

Vividwireless' current network is based on mobile WiMAX 802.16e technology. It operates in Perth, Sydney and Melbourne with more locations to come online early next year.

The company's trial LTE network would cover three base stations in the inner-city Sydney suburbs around Redfern and extend to Horsley Park in Sydney's west.

Only two of the three LTE base stations were on sites already included in the vividwireless network.

Horsley Park site is a new addition to vividwireless' infrastructure assets.

It was included to test the distance reach of TD-LTE as well as its performance in a "semi-rural, outer metropolitan environment," Mercer said.

All three base stations, which used Huawei SingleRAN kit, were assembled last week. Mercer did not rule out LTE trials using other vendors' equipment.

Mercer said that "more likely than not" vividwireless would run its LTE trials in the 2.3 GHz spectrum band, although it also held spectrum assets in the 3.4/3.5 GHz band.

"The TD flavour of LTE is being primarily developed for [those bands]," he said.

The ability to use existing spectrum assets could put vividwireless in a good position to take advantage of LTE.

While all of the three largest mobile carriers testing FDD-LTE technology had done so in the existing 1800 MHz bands, most were expected to wait until the digital dividend spectrum was auctioned before rolling out LTE on any scale.

Vividwireless would not have to wait or bid for digital dividend spectrum assets before deploying LTE in the major capital cities.

Huawei wireless marketing manager Terry Walsh expected most of the early opportunities for LTE deployments locally to come from carriers looking to make use of their existing spectrum assets.

Walsh said that when talking about LTE, "most people assumed" that it was an FDD conversation.

But the consensus among networking vendors was that TD-LTE was emerging.

"Whilst there's a number of FDD-LTE networks, TD-LTE is not far behind and there's a huge amount of commonality between the two [LTE] technologies," Nokia-Siemens Networks head of network sales in A/NZ Mike Smathers said.

Likewise, Ericsson's Chaisatien said the vendor had "done a lot of work in TD-LTE" in the region, pointing to demonstrations in Vietnam, Thailand and India.

"We see TD emerging but it's not yet the dominant flavour of LTE," Chaisatien said.

"At least not yet," added strategic marketing general manager at Ericsson Australia and New Zealand Kursten Leins.

Read on to page two for a rundown on the network demands carriers want to address with LTE and on the touted benefits, such as spectral efficiency.

Why LTE?

According to Leins, there was a "bias" towards seeing the evolution of mobile networks only in terms of speed.

"It leads us to automatically assume that LTE will be more of the same," he said.

Some early trials of LTE had focused outcomes on raw speed tests but, according to Leins, different operators globally were approaching LTE trials and rollouts differently.

"Some look at it as a speed game, others look at it as a price game – getting the lowest cost per bit, and others still look at the attributes of [having] an all IP network," Leins said.

"Speed is one benefit of LTE but it's not necessarily the prime driver and different carrier strategies globally will reflect that."

His colleague Chaisatien expected LTE – when it achieved large-scale commercial rollout – to allow carriers to close the ever-increasing gap between traffic growth and revenues.

Other benefits touted by vendors were the spectral efficiency of LTE compared to HSPA – which would allow carriers to deliver more data without requiring the big increases in network resource levels currently required to keep pace with booming data growth.

"Spectral efficiency is about delivering more bits for the bandwidth carriers have got," said NSN's Mike Smathers.

"Spectrum is the finite resource for carriers. On, HSPSA spectral efficiency [for the downlink] is around 1.3 bits per second per Hertz per cell [site] and about 0.3 bits on the uplink."

Smathers did not put a figure on how much spectral efficiency would improve under an LTE network architecture, saying it would be dependent on cell size, base station concentration, bandwidth and customer usage.

Other benefits touted as possible to achieve by upgrading to LTE were latency reductions and improved (but not equal) symmetry between downlink and uplink speeds.

"The ambition is for an uplink that is half to one-third of the downlink speed," Chaisatien said.

"That's really driven by the need to push more content into the cloud. [Uplink compared to down] is a factor of 10:1 on HSPA networks today, but with LTE it will get closer to a 3:1 or 4:1 ratio" compared to the downlink.

Read parts one and two of iTnews' investigation of LTE trials in Australia here and here.