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From Optus

"This moment is a defining one in Optus' and the Australian telecommunications history – it's leading edge, an Australian first and a first for the southern hemisphere – we've just made a UMTS900 call – It's just very exciting. " These were the words from Darren Rogers, Optus' Network Strategy Manager, moments after he made the first UMTS900 call in Wongarbon, Central West New South Wales.

For over twelve months, Optus has been tirelessly working on its future mobile technology strategy, ensuring that the choices that are made will be following the leads of the world's largest telecommunications markets and in doing so, ensuring that supply of equipment enjoys large economies of scale and wider compatibility in more regions around the globe.

For some time, the question has been whether it was possible to successfully deploy 3G (UMTS) within the 900MHz band in parallel with a mature GSM900 network. Providing in-band UMTS would result in swifter delivery to market to existing footprint areas and expansion costs to new areas would also be more cost effective.

There have been some successful tests in Europe, but there is nothing better than proving something in your own backyard. To undertake this exercise, Optus partnered with Huawei who were more than keen to show that UMTS900 is a reality.

"We only agreed to undertake a trial in August and, frankly, many people thought the idea of making a UMTS900 call before Christmas was a pipe-dream. But we did it." Dr Brendan Jones, Radio Networks Performance Manager said.

Within 3 months of agreeing to the trial, Huawei and Optus had built and tested a UMTS900 network in Central West New South Wales. In addition to the UMTS900 equipment, we included UMTS2100 equipment to undertake comparative testing between the two spectrum bands.

The majority of the world's 3G networks are operating within the 2100MHz frequency spectrum band. The existing Optus 3G network has been deployed within this band and we will continue to deploy this moving forward in many areas. The biggest difference between the two spectrums is the breadth of coverage they provide from a single base station. 2100MHz signal does not travel as far as 900MHz, thus more base stations are needed to provide wide area coverage.

In densely populated areas, the need for more base stations is also related to the demand for the service – capacity management is crucial in 3G network planning. This is why today the symmetry of our 2G and 3G base stations is different. It allows us to ensure both coverage and capacity requirements are met.

Our GSM metro network already had a high density of base stations, and with the mix of sites the Optus-Vodafone Joint Venture offered, we could ensure we achieved the right balance for coverage, both on-street and in-building whilst managing the capacity aspect of our 3G network.

UMTS900 is a suitable frequency band when considering deployment in less dense areas. We have already done an exceptionally good job in deploying our national GSM network which today covers more than 650,000 square kilometers of Australia's landmass reaching approximately 96% of the Australian population.

With over $2.5 billion invested to date in our GSM network, it makes sense to investigate how to minimize capital expenditure by making use of existing investment when deploying new technologies.

An important factor in the development of UMTS900 is that it should operate seamlessly with existing carrier's 3G and GSM networks. Operators have spent significant money on 3G spectrum in the 2100MHz band and the majority also operate GSM networks in the 900MHz band. As part of the 3GPP standard, these two networks work seamlessly together for most services and it's crucial this compatibility flows onto UMTS900. Markets such as Europe and Asia, which account for more than 80% of the world's GSM and 3G use in the 900/2100MHz spectrum bands respectively, are therefore setting the standards to ensure this compatibility exists. This will ensure an excellent user experience, wide availability of compatible equipment and better roaming options for the world's 1.8 billion users.

The network equipment manufacturers, including Huawei, Ericcson and Nokia-Siemens are already trialling, or intend trialling UMTS900 base station equipment. They also recognize that this is the next step in 3G deployment as carriers move into less populated areas requiring wider area coverage.
The trial involved a myriad of Optus and Huawei staff and is certainly an achievement that all can be very proud of. In particular, Huawei were able to deliver in the timeframe we required.

"This is an important moment for both Optus and Huawei. Focusing on customers' needs and continuous innovation, the UMTS, HSPA, GSM, CDMA and WiMAX mobile solutions of Huawei are now serving over 200 million subscribers in more than 80 countries. Huawei is committed to provide innovative solutions that create maximum value for our customers." Joseph Zho, Managing Director of Huawei Australia said.

For many, the significance of what was achieved is still setting in and was certainly an early Christmas present for those that put in the many hours proving a suggested engineer solution is a possibility.

We are delighted with the successful UMTS900 Demonstration in Dubbo and the Central Western district of New South Wales. We believe this is the first UMTS900 test conducted in Australia and this is an historic moment for both Optus and Huawei.

The joint teamwork between Optus and Huawei has been pivotal to our success and we look forward to the future opportunities that this technology brings to Optus. The success of this UMTS900 trial was only possible due to the hard working efforts of Optus and Huawei.

"Thanks to our engineers and network people, project managers, technical staff, marketing strategy and the commercial team, and so many more from other divisions who endeavored to complete the trial in such a short period of time." Harry Hou, Director of Huawei Australia commented.

Despite being trialed in a few markets in Europe, there were some challenges that were faced in getting the trial up and running. Brendan Jones and his Radio Networks Performance team was responsible for defining the scope of the radio access network part of the trial, identifying the trial location and liaising with Huawei on technical and radio issues.

In addition, the team liaised with our Regulatory group in relation to spectrum licensing issues and lead the analysis on how we can share our GSM spectrum with UMTS900 and not degrade service to existing GSM customers.

"UMTS900 equipment is still in the development stage. It is not yet a commercial product and what equipment there is has barely come off the production line. There were challenges in sourcing enough UMTS900 transmitters from Huawei's factory for the trial, and getting the Antenna Sharing Units to enable us to combine GSM and UMTS services on the same antenna." Brendan Jones said.

"The equipment had to be tested in the Optus lab before deploying in the field, and the timeframe was extremely tight. There were also regulatory hurdles to overcome because this was breaking new ground in Australia." Brendan went on to say.

One of the benefits of UMTS900 is the ability to utilize much of the existing infrastructure, minimizing costly upgrades or acquisition of new sites to provide wide area coverage. Not only is this a cost saving, it also makes for speedier deployment.

As part of the trial, we wanted to compare the propagation differences between 3G at 2100MHz, 900MHz and our existing GSM900. To achieve this, we deployed 3G900 and 3G2100 equipment to our existing base stations. Whilst we could have run separate antennae and feeders for each of the bands, we were in parallel assessing various deployment options.

"In-band deployment has many advantages and one is the re-use of existing antennae and feeders. When you're looking at upgrading our rural base stations, you want to minimize antennae and feeder additions as these can be costly." Rod Cassidy, Optus Project Manager for the trial said.

Our focus in regional areas has been building good tall sites – be they 60 metre lattice towers or 100 meter guyed masts. These sites allow us to maximize our coverage in line with our network strategy and feedback from our customers indicates they are enjoying our significant investment that results from building good sites.

"Minimizing feeder duplication from the shelter to the antennae and subsequently the need for separate antennae reduces the capital cost to upgrade each site and in some cases, additional lease space on the tower. This does however have its own challenges, requiring filters to be placed between the GSM900 and UMTS900 equipment before it is combined into the same feeder." Rod continued.

When deploying another technology into the same spectrum, network operators need to be mindful of the capacity implications on its existing services. A process known as re-farming needs to take place. Greg Dunn, Manager of our Queensland National Planning group explains: "In the world of GSM, each carrier has a certain number of frequency 'channels' allocated for use in the network. It is these frequency channels that allow users to make and receive calls, SMS and GPRS across GSM networks."

"To achieve a large coverage area, mobile networks use 'cellular' technology which is the process of allocating different frequency sets to sectors on multiple base stations – sometimes referred to as the honeycomb effect. These frequency settings are carefully planned to ensure that base stations with overlapping coverage do not share the same frequency; otherwise they will interfere with each other causing poor voice quality or in extreme cases, dropped calls." Greg said.

It's important to remember that the mobilisation of telecommunications equipment is what has made the service so popular. The ability to maintain communications whilst moving has and it is for this reason we have more base stations with overlapping coverage to ensure smooth handovers as you move around.

Frequency planning is a key part of operating an efficient and quality GSM network. Just as you should regularly tune and service your car to ensure it runs well, Optus undertakes frequency re-tunes as the cellular environment is dynamic in that we implement new sites, adjust antennae configurations and even the changing natural and man-made environment has an impact.

To implement UMTS900 we needed to use half of the existing Optus GSM900 spectrum band. We essentially, split the Optus band in two, half each for GSM900 and UMTS900. This meant that we needed to re-farm or clear part of the existing GSM band before we could turn on the new UMTS sites.

"The re-farming process for the Dubbo and Central West trial area required a frequency retune of 17 GSM sites in the area, using the halved frequency band. Our challenge was to limit any customer impacts so they did not experience any degradation of voice quality or an increase in dropped calls," Greg continued.
In choosing a location to trial the UMTS900 service, one of the criteria was to challenge the ability to deploy in-band technology in an area where our GSM network handled significant traffic. This ensured we could see what, if any, customer impacts there would be and provided a clear insight into the planning scenarios we could implement across Australia. Optus GSM subscribers are used to a high level of quality from our network and degradation of service is not an ideal outcome just to provide a new technology.

To accomplish the re-farm, the Radio Network Performance team has developed retune tools based around Mobile Measured Frequency Planning, which uses actual measurements from the mobile phones in the area that are to be retuned. An Automatic Frequency Planning tool was then used to calculate the best frequencies to use at each base station, the calculation taking over 12 hours of computer processing time.

"Using these tools, the retune was implemented successfully, with drive test data and statistics indicating that call quality and dropped call rates had actually improved in keeping with our objective of not degrading service but actually enhancing experience on our GSM network." Greg went on to say.

Using the statistics from this trial and reviewing traffic analysis from our base stations, the Optus team has been able to tabulate areas where deployment of UMTS900 would be possible given traffic and frequency planning challenges. Ashish Pilani, 3G Strategy Manager explains how Optus may look at its deployment options.

"We have a large amount of Spectrum in the 2100MHz band which we intend to make good use of. Even in areas where we have this spectrum, our preference may be to deploy UMTS900 to take advantage of the lower cost-to-market and wider coverage. In other more densely populated areas with 'metrolike' traffic volumes, we can utilize 2100MHz."

"With GSM, carriers initially launched in most markets in the 900MHz band. Governments released 1800MHz spectrum in the late 1990s which allowed carriers to overlay a second GSM frequency to soak up traffic – it's often referred to as a dual-band network. Similarly, it would now appear that we will see dual-band 2100/900MHz devices which will allow carriers with these spectrum bands to manage capacity better in years to come on 3G." Ashish said.

Further technical trials will continue with the UMTS900 network in Central West New South Wales over the coming months. In parallel our Technology and Planning Teams, Network Strategy and Engineering groups will continue to work with network partners and make a technology decision mid-way through 2007.
It's certainly an exciting time and the decision that we make will ensure we work towards a network based on global standards, maximizing global equipment scale and compatibility – a key to offering a competitive range of devices such has been the case with our GSM network.


Links: Comments by some of those involved

Cy Carter, Senior Technical Specialist provided 3G Technical Consultancy to the trial

What does UMTS900 mean to you /industry:

For me UMTS 900 means being able to extend our 3G services to all of our existing GSM customers around Australia by using the very same base station sites as our mature GSM network. It means seeing the fruits of many years of work in Optus developing our mobile network to meet even higher customer expectations. For the industry it means continuing to challenge our competition and providing choice and keeping pace with new customer expectations.

What challenges, if any, did you face in your role in the trial:

Key challenges included the tight timeframe, ensuring the trial did not impact on the high performance of existing mobile network, clarifying the objectives of the trial, specifying design constraints and ensuring that design of the trial network would meet the objectives. All the while working on other high priority projects within Optus.

General Comments:

I was very impressed by the commitment, skills and hard work done by all involved both within Optus and the vendor of trial network equipment. All parties worked together towards a common goal and achieved it. It is a good example of both Optus and the vendors ability to 'make it happen'.

Dr Brendan Jones, Manager Radio Network Performance – National

What does UMTS900 mean to you/industry:

It's a very good technology option for providing 3G services to regional and rural areas, and would enable Optus to tackle Telstra head-on and gain an advantage. Each UMTS900 site would cover a much larger area than a UMTS2100 site, reducing the cost of rollout. The global support for UMTS900 is likely to be many times larger than UMTS850.

General Comments:

Working on this type of project is what makes Optus so exciting. It is truly ground-breaking. You can count on the fingers of one hand the number of operators around the world who have field tested UMTS900 – and Optus is one of them.

A team member from our NSW Radio Planning Team

Role in UMTS900 Trial:

Assisted Radio Network Performance in the implementation of the trial such as the retune and edge of coverage drive tests; monitoring the performance of sites; liaising with Huawei regarding their requests for information; liaising with the operations centre regarding locking down of transceivers as part of the re-farming process.

What does UMTS900 mean to you/industry:

If Optus is able to deploy UMTS900 it will give us the opportunity to challenge Telstra's Next G network in rural areas.

What challenges, if any, did you face in your role in the trial:

Attempting to maintain our high level of service in the region due to re-farming of the Optus GSM900 spectrum. We were successful with our efforts which involved using modified frequency plans and the implementation of intelligent network features.

General Comments:

The challenge will be to deliver a product that will convince customers of Optus' ability to challenge our competitors in terms of performance and service.