Caltta Technologies Co., Ltd.
Caltta Technologies Co., Ltd.
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Caltta Ensures Smooth Communications for 2022 Beijing Winter Games

Caltta Ensures Smooth Communications for 2022 Beijing Winter Games

1)End Users: committee and venue staff, security personnel at three competition zones for the Beijing 2022 Winter Olympics, including Beijing, Zhangjiakou and Yanqing

2)Sector: sports and major events

3)Project Time: deployed and launched in 2021

4)Product: LTE broadband trunking system and terminals, PDT narrowband trunking network

Repeater System


After the successful bid for the Beijing 2022 Winter Olympics, Beijing made a solemn commitment to the International Olympic Committee to build a private broadband trunking network to meet the organizational needs of the Winter Olympics. Since 2019, Beijing has gone through multiple phases of base station and core equipment upgrade and transformation and fully launched the entire 1.4G private communications network before the Games.


The Beijing Winter Olympics and Winter Paralympics were held across two cities and three major areas. The terrain is complex; some arenas were in plains and some in mountains. Real-time communication, commanding, and dispatching must be realized among the three areas to ensure safe and smooth running of the Games. At the same time, the private communication network should cover every corner of the city to ensure that urban security and emergency situations can be dealt with in a timely and effective manner.

1)The wide area and complicated terrain required full coverage of the communication network, and the three competition areas needed interconnection.

2)The command center must be able to monitor the situation in each competition area by live streaming and oversee the entire competition process.

3)The communication system required extra-large capacity for huge amount of data transmission and heavy traffic.

4)Radio devices and infrastructure must keep working continuously at a low temperature environment of -30℃.

Rechargeable Wifi Extender


There were three competition zones for the 2022 Beijing Winter Olympics, including Beijing, Zhangjiakou, and Yanqing. Among them, Beijing competition zone used LTE broadband trunking network, which worked in 3GPP Band45, and Zhangjiakou competition zone used the PDT trunking system.

To ensure unified commanding, coordination, and emergency response, the LTE broadband trunking network in Beijing and the PDT narrowband trunking network in Zhangjiakou were interconnected. Through broadband and narrowband hybrid grouping, private call, group call, short message, dynamic regrouping, emergency call, positioning, and other services, the interconnected system could meet the requirements of unified user and security management, operation and maintenance, command and dispatch during the Games.

This kind of “2+4" broadband and narrowband convergent solution that connected different networks fulfilled the interworking between competition zones in Beijing and Zhangjiakou. It greatly improved the efficiency of commanding and dispatching with high level of intelligent management. This convergent solution set a benchmark for communications systems of major sport events.

Solution Highlights

Smart Operation, Visualized Dispatching

In the MOC main operation center, supervisors were able to see the real-time location of each group member on the map and also retrieve the mobile videos from the radios of one or more group members in real time. Units can form different groups to communicate independently or jointly across departments.

Voice, SMS, positioning, video, data, and other information were available in every corner of event zones, such as ski tracks, airport high-speed rail and highways. A panoramic view and one-click command were achieved at the command center’s dispatch console, which provided secure and efficient communications and visualized dispatching for the Winter Olympics.

Dual Backup, High Reliability

To ensure reliable operation of the system, a variety of backup methods were adopted, including dual backup of transmission links, dual backup of remote disaster recovery, and dual backup of physical devices of core switching units. The two sets of system were mutually main and standby. When the main system equipment had a failure or breakdown, it automatically switched to the standby node in a different place to quickly restore the services.

At the same time, the physical device of the core nodes was double-backed up, so that when a single node failed or was even physically damaged, services carried on smoothly without interruption.

Push-to-Talk Instantly without Losing the First Word

The referees of the Beijing 2022 Winter Olympics have extremely high requirements for the response of the system. The Committee clearly stated in the requirements: the delay of establishing a private call is ≤300ms, the delay of establishing a group call is ≤300ms, and the delay of applying for the floor is ≤300ms, which must achieve the effect of "push-to-talk instantly without losing the first word". Therefore, time-consuming analysis was carried out segment by segment for the duration of narrowband trunking group call connection, including the narrowband radio PH790 sending the call initiation message, the system issuing the channel assignment message, the uplink voice header from radio, downlink voice header delivered by the system, etc.

The process optimization was carried out for each segment. After repeated optimizations and tests, the end-to-end delay of the media plane finally reached within 260ms, and the voice was clear without losing any word. The system successfully passed the test of the International Snow Federation.

Low-temperature Resistant Battery, Long Battery Life

The average outdoor temperature in the Zhangjiakou competition zone was -20°C, sometimes -30°C. To guarantee stable operation in the low-temperature outdoor environment, the narrowband radio PH790 had been optimized in terms of cold resistance with improved power mode, professional low-temperature resistant battery. It had a reduced shutdown threshold at low temperature, passing the evaluation and certification of the authoritative organization. The battery life at a low temperature of -33 ℃ (the ratio of transmit, receive, and standby is 1:1:8) was 8.5 hours.

Repeater Outdoor


As the provider of the trunking communication system for the Beijing Winter Olympics, Caltta facilitated the setup of the 1.4G B-TrunC broadband trunking network in Beijing and the 350M PDT narrowband trunking network in Zhangjiakou; and successfully completed the convergence between B-TrunC and PDT, B-TrunC and TETRA. The interconnection between systems and networks realized the intercommunication among different networks and regions.

This large convergent private network achieved continuous coverage of venues, service facilities, main roads in the city, major suburban districts, and the Beijing and Yanqing divisions of the Winter Olympics. This Winter Olympics and Winter Paralympics is the first time when an 1.4G private network independently undertakes the task of the first-level communications and commanding network for major international events. This network was used for testing events, technical drills, torch relays, opening and closing ceremonies, and all the competitions. Especially important for the torch relay, the event was live streamed through the command platform. In case of emergencies, responses can be dispatched quickly.

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