Inside XT

Between December 2009 and February 2010 Telecom’s XT Mobile network experienced a series of disruptions.

14 December, 2009 The outage was caused by a corruption of software during a routine operational process. This caused a signalling storm into the southern RNC (Radio Network Controller) and an impact of several hours for XT users on the Southern RNC. 27-29 January, 2010 The outage was caused by a hardware failure in a router. The normal reset then caused a signalling storm that caused an overload on the Southern RNC and impacted all clients on the southern RNC with degraded service for several hours on the Wednesday, and up to 58 cellsites serving were out of service until the Friday evening, 29 January, at 10pm. Thursday, 17 February, 2010 Was an issue with the first of our migrations of Southern cellsites to the new RNC in Taranaki and the Hutt Valley. This affected 16 cell sites from early morning until 2pm due to a process failure within the migration process. Monday, 22 February, 2010 At around 4:15pm on Monday the Southern RNC experienced a severe reduction in voice traffic. Up to 81 of the 450 cell sites served by the RNC lost all services, for about an hour and 45 minutes all voice traffic was lost south of Taupo, out side of this window customers experienced severely degraded voice calling service and patchy SMS and data. All sites were restored following a RNC restart which took the Christchurch RNC out for about 20 minutes at 3am. Full service to all sites was in place by 4am.

There are currently a number of programmes of work under way to improve XT. Much of this work was already planned as part of the usual network upgrade and optimisation work carried out to cater for increasing numbers of people using the network, and additional work is under way to address the issues that affected the XT Mobile Network.

Improving Coverage

Improved coverage will increase the signal strength and reach for the existing cell sites on the XT Mobile Network, and we expect that it will reduce the instances of dropped calls experienced by XT Mobile Network users. We are building additional cell sites – 26 new sites have been added since XT launched (as at 30/04/2010) – and we are installing Tower Mounted Amplifiers (TMA) on existing cell sites. A TMA amplifies the incoming (receive) signals from the cell phones that would otherwise be too weak to travel from the antenna to the base station, thus providing better coverage and service. This ongoing programme will also include more regular independent testing to ensure quality is maintained. To date (30/04/2010) 92, out of 338 TMAs have been installed.

Improving Capacity

This programme will increase the capacity for calls and data as usage grows, and improve coverage in high density areas. We have reviewed our capacity management programme to ensure we more accurately track trends and predict future network demand, due to growth in the use of text and increased use of devices such as smartphones and PDAs. We are also working to leverage our existing fibre backhaul capacity to improve the voice quality experience for users on cell sites.

Increasing Resilience

Increasing the number of Radio Network Controllers (RNCs) and their processing power will mean that if there is an event that impacts an RNC, the regional impact will be much lower. It will also reduce the effect of unusual traffic spikes on the existing network. We were recently installed two more RNCs bringing our number of RNCs to a total of four deployed, with two RNCs in Christchurch and two in Auckland.

Update on these programmes of work

Planned work:

All these different programmes of work mean things are happening on the XT Mobile Network in different parts of the country, all of the time. To find out which parts of the country we’re working on right now, visit the network status page. Note – This activity is subject to change due to environmental factors such as weather and resource availability.

Following the series of XT Mobile Network outages from December 2009 to February 2010, Telecom has commissioned a full independent review of the network, with the full co-operation of our service partners Alcatel-Lucent.

Telecom CEO, Paul Reynolds, has said Telecom will leave no stone unturned as we commence the independent review of XT to ensure we are giving New Zealand the network it demands and deserves. Telecom has appointed Analysys Mason to conduct its independent review of the XT mobile network. The Analysys Mason Group (AMG) is a highly respected UK-based international consultancy specialising in telecommunications, technology and media and bring world’s best practice around design, build and operations of mobile networks. AMG are bringing a multi-disciplined team of up to seven specialists who have in depth knowledge of the design, planning and operation of 3G and IP networks from a range of technology suppliers. Their consultants were hand-picked for their knowledge of radio, core, and transport networks and their understanding of operational processes. AMG are often called on to undertake similar in-life network reviews for a range of clients. The review is currently under way and covers the design, build and operation of the XT mobile network. It is expected to be complete in April, when findings will be made public. During the review, Analysys Mason will be engaging with Telecom staff, customers, Alcatel-Lucent and other key stakeholders. If you’re a business customer then register here and we’ll email you with a summary of the independent review when it’s published.

Telecom's XT Mobile Network was launched in May 2009.

The XT Mobile Network was built to world-class standards, to deliver 3G mobile services to New Zealanders and enable Telecom to deliver leading-edge mobile services now and in the future. The WCDMA technology that XT is based on is used by a number of leading mobile providers around the world, including AT&T in the United States and Telstra in Australia. The XT Mobile Network was built by Telecom’s long-time network partner Alcatel-Lucent. Alcatel-Lucent is a leading player in the WCDMA/HSPA market. Its technology is deployed in 60 customer networks across 40 countries, serving four out of six of the biggest networks in the world, including AT&T, SKT and KT in Korea and Vodafone in Italy.

A list of useful terms and their definitions.

RNC – Radio Network Controllers. All of the XT cell sites are connected to RNCs, which then connects the cell sites back into the core of the network. The RNCs help manage traffic on the network. Cell sites – A mobile phone site is a low-powered radio station that sends and receives radio signals to and from mobile phones or other mobile devices (such as PDAs and mobile broadband modems) in a specific area. A typical site will consist of three or more antennas attached to a building or a mast, a small cabinet containing the electronic equipment needed to send and receive radio signals and a communications cable or microwave radio dish to connect those signals to the main telephone network. TMA – Tower Mounted Amplifiers. TMA’s reduce noise and improve the Receive Gain of the antenna, allowing the cell site to remain at its optimum use and ensuring call stability. TMAs are being installed on over 400 of our cell sites to make our coverage footprint stronger. SMS – Short Message Service. Also known as text messaging. Mobile data – Mobile data is a generic term for Mobile Broadband used to describe the transport layer which carries traffic on the mobile network that is not voice or SMS. Mobile broadband – the name used to describe high speed wireless Internet, accessed through data enabled device. This includes mobile web browsing, email and other non-voice or sms services wireless high-speed internet access through a portable modem, telephone or other device. 3G – Third Generation wireless format. Enables high speed data and voice services. WCMDA – Wideband Code Division Multiple Access. WCDMA is a third-generation (3G) mobile wireless technology and is the underlying technology protocol for the XT network. GSM – Global System for Mobile Communications. This is a 2G technology primarily used for voice, SMS and will enable Telecom customers to roam globally. The evolution path from 2G GSM is 3G WCDMA