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Network Services for Key Events (PDF-407K)

Introduction

In the April 2008 issue of HUAWEI SERVICE we included an article describing our provisioning, installation and commissioning for two BTS, one at 5,200 metres and one at 6,500 metres above sea level (ASL), to enable China Mobile provide mobile coverage for the Olympic Torch Relay to the summit of Mount Qomolangma.

Following the installation and commissioning of the wireless coverage on the route to the Summit of Mount Qomolangma, the Communications Guarantee project is an extremely important, some might say unenviable, task for Tibet Mobile. The following article describes the subsequent support we provide for this prestigious event.

Coverage Requirement

The Olympic Torch route requires to cover the Qomolangma Base Camp, the Interim Camps, the Attack Camp and at the Mount Qomolangma Summit.

To satisfy this requirement, a BTS was located just above the Qomolangma Base Camp (5145 metres ASL) at 5,200 metres ASL, and at the Interim Camp at 6,500 metres ASL.

The BTS located at 5,200 metres ASL provides wireless coverage to the Qomolangma Base Camp and to the Summit with a circumference of 20 kilometers. And the BTS located at 6,500 metres ASL provides wireless coverage along the Torch Relay route.

Guarantee Plan

Because the Torch Relay route makes a dog-leg turn between the Qomolangma Base Camp and the Camp at 6,500 metres ASL, Tibet Mobile provided a repeater, located at 5,700 metres ASL, to fill in any holes in coverage caused by the surrounding terrain, i.e. ridges and valleys, and to provide coverage to the Interim Camp at 5,800 metres ASL. Figure 1-2 illustrates the locations of the BTS and repeater.

BTS Reconfiguration

Through discussions with the China Mobile Group Design Institute, and through the predicted traffic model employed, our traffic analysis and calculations led to a decision to reconfigure and expand the BTS at 5,200 metres ASL from the original O4 configuration (Omni-directional, 4 carriers) to a S2/S4 configuration (Two-sectors, 2 carriers in the South sector towards the Summit & 4 carriers in the North sector towards Qomolangma Base Camp).

The repeater site was equipped with a Yagi antenna in the direction of the base camp BTS in order to make use of the capacity of the S4 sector, as we wanted to maintain all of the S2 sector capacity for the assault on the Summit. The repeater site provides frequency translation which avoids any interference with the other BTS channels.

Power Conservation

The line-of-site distance from this BTS to the Summit is approximately 20 kilometres. To ensure a good Received Signal Level at the Summit, we increased the BTS Carrier Transmit power from 40 watts to 60 watts and adopted a configuration with zero combiner loss in the S2 sector towards the Summit. Additionally, we worked with the China Mobile Group Design Institute to repeatedly produce coverage predictions, under different tilt-angle scenarios, and worked with Tibet Mobile to readjust the up tilt-angle of the S2 antennas to optimize the coverage at the Summit.

Back-haul Transmission Backup

The back-haul from the Qomolangma Base Camp BTS at 5,200 metres is provided by a micro-wave link to the BTS at Flannelette Temple, 8 kilometres away. After discussing with the Network Department of Tibet Mobile we added a set of 16E1 microwave transmission equipment as a back-up to the existing system. Additionally, as a belt-and-braces precaution, a temporary vehicle mounted satellite transmission facility was also provided by China Mobile as a back-up transmission path so, should the micro-wave system back to the BSC site, located at Shigatse, fail at some point along the route it can by-passed through the satellite transmission link.

As an additional precaution, to ensure the success of this historic event, China Mobile provided a truck mounted temporary BTS, configured S8/8/8 (Three Sectors, 8 carriers per sector) located at the Base Camp. These temporary truck mounted facilities were there to provide redundancy during this "nothing must fail" project and additional capacity, should it be needed, for a major, once-in-a-life-time media event. Where as, the Huawei BTS sites and the repeater are permanent infrastructures to support all future Chinese Qomolangma expeditions.

As there is no Line-of-Sight path between the BTS at the Interim Camp at 6,500 metres ASL and the Base Camp BTS at 5,200 metres ASL, which would facilitate a micro-wave transmission path, we provided a fixed satellite base station to provide the link for the back haul between the Interim Camp and its BSC site, located at Lhasa.

Adjustment and Optimization of RF

The BSC data configuration, including channel adjustment, rate of static powers, occupancy of the S2 Sector channels and configuration for the satellite transmission back-up for the BTS at 5,200 metres ASL, were completed.

The assignment policy was adjusted. According to the adjustment, the S4 Cell Sector channels were assigned for users near the base camp so that they did not pre-empt the S2 sector channels which cover the summit. We confirmed the functional configuration with the technical experts in the core network of Tibet Mobile.

Final Test

We conducted the health check on the core network equipment in the checklist according to the requirements of the Mount Qomolangma Torch Relay project for the EDGE Data, half-rate and other functions. Thereby the support of the core network for the BTS services on Mount Qomolangma could be ensured.

Finally, the R&D department of Huawei conducted a simulated verification in the Laboratory according to the channel configuration of the BTS on Mount Qomolangma.

After completing the coverage tests for each of the Camps, Xinhua News Agency employed climbers for the communication test at a height between 7,028 metres and 7,790 metres ASL. For the area at more than 8,300 metres ASL, no coverage tests were possible due to the poor prevailing weather conditions at that time.

Service Guarantee Implementation

We made efforts in the following aspects to guarantee the communication for the torch relay:

Organizational Structure – Huawei, and its Representative Office, deployed significant Human Resources which laid a solid foundation for the successful outcome of the Communications Guarantee Project. The overall project was divided into the following teams:

• On-site Implementation Team
• R&D BTS Testing Team
• R&D BSC Guarantee Team
• R&D Network Optimization Team
• Market Co-ordination Team
• Logistics Team

The whole project involved a total of 28 full-time members.

BTS Hardware & Summit Coverage – It was essential that the BTS must be able to operate normally after the deployment, reconfiguration and capacity expansion. Any alarm indication, no matter how trivial, was eliminated. All BTS hardware was rigorously inspected to locate and remove any potential hazards, including whether each RF cable connector was tightened correctly, whether the antenna feeder connectors were leaky, etc.

We communicated with the offices of Xinhua News Agency as to their wireless service requirements on the Summit. Based upon this communication, the R&D personnel calculated the coverage prediction for the S2 sector at the Qomolangma Summit.

We requested the China Mobile Group Design Institute to reassess the up tilt- angle of the S2 sector antennas and, finally, in accordance with the Design Institute we adjusted the S2 antenna up tilt-angle from 8 degrees to 10 degrees, thus guaranteeing an optimized coverage of the S2 sector at more than 8,300 metres ASL and on to the Qomolangma Summit.

BTS On-site Implementation Tests & Data Configuration Optimization – Based upon the On-site Implementation Team' s test results and the feedback from the end users on-site, the R&D BSC Guarantee Team and R&D Network Optimization Team adjusted the BTS Channel and PCU Data configurations iteratively to optimize the communications services.

Spare Parts & Components – After the completion of the on-site tests and performance optimization, we prepared sufficient spare parts and components for the BTS3006C at 5,200 metres ASL to support the communications at the Base Camp and the Summit, providing the Tibet Mobile staff with training on maintenance and deployment to ensure qualified troubleshooting staff was available at all times. Additionally, we provided the all the necessary spare parts and components for the BTS3002C at 6,500 metres ASL, to support the communications along the route for the interim Camps, again providing product maintenance training for the local maintenance department of Tibet Mobile near Mount Qomolangma. In this way we could ensure that the Tibet Mobile construction and maintenance personnel were fully prepared for the troubleshooting of the BTS hardware, should the need arise.

7/24 Remote Monitoring – On completion of the on-site work, the On-site Implementation Team returned to the Tibet Mobile Network Management Centre to monitor the traffic indicators of each cell sector of the two BTS. Each day they collected the traffic statistics for analysis and submitted the results to the R&D Guarantee Teams and the related offices of the China Mobile Group for review. When the torch relay team arrived at the camp at 6,500 metres ASL, the traffic volume at peak hours in two days reached 0.99 Erlangs and the BTS congestion ratio (all Traffic Channels busy) reached 93%. The situation was reported to Tibet Mobile, who organized the China Mobile Group Design Institute and Huawei for the capacity expansion for the BTS at 6,500 metres ASL. However, after taking all factors into consideration, the expansion plan was abandoned so as to not interrupt communication service during the torch relay event.

Traffic Analysis - Over the period that the Olympic Torch Relay scaled Mount Qomolangma Huawei' s employees, at the front line and in the rear, worked in shifts around the clock. They provided support to the related departments of Tibet Mobile to analyze the traffic volumes, number of voice and data users, data transmission rates and collected/analyzing photo transmission data. Overall, they helped provide the fundamental background support in guaranteeing successful communications during this amazing event, allowing the worlds public to see for themselves the Olympic Torch making its way to the Roof of the World.

The Olympic Torch on the Roof of the World

Finally, after being delayed for nearly two weeks by bad weather, on Thursday 8th of May 2008 the final assault was made on the Summit by the 19 member Summit team. They broke camp, from the Attack Camp at 8,300 metres ASL, at dawn and reached the Summit some 6 hours later. The flame was carried in a special canister during the ascent and, when approaching the Summit of 8,850 metres (about 29,000 feet) ASL, the team used a wand to pass the flame from the canister to the torch, which has been specially designed to withstand the strong winds and low oxygen levels that prevail on the Summit.

The Canister carrying the Olympic Flame

The Olympic Torch was lit by Norbu Zhambu, the youngest member of the team, and then carried on a final 30 metre relay to the Summit by the five torch bearers. Each torch bearer inched forward just a few metres before passing on the torch to next bearer. The Team Captain, Nyima Cering, was the third torch bearer who shouted the 2008 Olympic slogan of "One World, One Dream" on receiving the torch. The final torch bearer, a Tibetan woman named Cering Wangmo, stood in silence at the summit with the torch while her other team members unfurled Chinese and Olympic flags around her.

The Olympic Torch at the Roof of the World

This amazing achievement will go down in the annals of Olympic History as when the Olympic Flame made it to the Roof of the World, and hopefully in some small way, Tibet Mobile, in close co-operation with the China Mobile Group Design Institute and Huawei, played an important role in guaranteeing the success of this incredible event in allowing the world to see the Olympic Flame on the Roof of the World.