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March 9, 2016

Guest Blog: Enabling Cloud-RAN in Hong Kong with Mobile Fronthaul

By Byron Chiang

Chief Technology Officer of Hutchison Global Communications

Yesterday, Hutchison Global Communications Limited (HGC) and Infinera announced HGC’s innovative new mobile fronthaul service in Hong Kong, enabled by Infinera’s Mobile Fronthaul Solution.

A subsidiary of Hutchison Telecommunications Hong Kong Holdings Limited (HTHKH), HGC owns an extensive fiber-optic network servicing Hong Kong, Kowloon and the New Territories, providing all aspects of connectivity including cross-border routes and submarine landing stations. In addition to providing residential broadband services, HGC offers a comprehensive range of fixed-line telecommunications services to international and local carriers and data center operators in Hong Kong and overseas. Since we work closely with the mobile arm of HTHKH – 3 Hong Kong, we have plenty of experience in the transport requirements for mobile networks.

Yesterday’s announcement is exciting as it demonstrates HGC leadership deploying the latest mobile technologies, including the Infinera active Mobile Fronthaul Solution. We are now turning up one of the first mobile fronthaul services to mobile operators in Hong Kong, including 3 Hong Kong, our sister company.

This new service utilizes our extensive fiber network and Infinera’s active Mobile Fronthaul Solution to provide one of the world’s first commercially available mobile fronthaul services. In this deployment, we used the transponder-based active option, one of the options available within Infinera’s portfolio of passive, semi-passive and active Mobile Fronthaul Solutions. With this, HGC now offers wholesale services that support all common public radio interface (CPRI) v6.1 rates, all the way up to 12 gigabits per second (12G), with the transponders providing a clear demarcation point for the service.

As part of our selection and verification process we tested what we determined to be the top mobile fronthaul solutions to ensure that the challenging requirements for CPRI transport could be met in a real network.

One challenge is that mobile fronthaul networks are typically limited to 20 to 40 kilometer (km) reach due to the latency budget of the CPRI protocol. The latency budget has an overall limit of 800 microseconds (µs) for the round trip from the remote radio head (RRH) in the cell site to the base band unit (BBU) in the central office and back to the RRH. Most of the latency budget is taken by the BBU processing, typically leaving 100 to 200 µs per direction for transport, which equates to 20 to 40 km of fiber. Any active electronics in the fronthaul network will eat into this budget, so ultra-low latency is critical for a viable fronthaul service.

Another technical consideration is ensuring that the synchronization information from the backhaul service is seamlessly passed from the BBU to the RRH in the cell site equipment via the mobile fronthaul network. Once again, the addition of active electronics in the mobile fronthaul network can have a negative impact on this synchronization transfer.  In order to compensate for this, the deployed mobile fronthaul network needs to have a very high-quality transparent synchronization transfer. Our lab evaluation verified that Infinera’s Mobile Fronthaul Solution not only met but exceeded these requirements. As a result, we provide mobile operators with an ultra-low latency mobile fronthaul service with outstanding synchronization performance.

One might ask, why this is so important to the mobile operators and residents of Hong Kong? Mobile fronthaul is a key enabler supporting the new trend of centralized and cloud-radio access network (C-RAN) architectures in mobile networks. Not only does C-RAN bring economic advantages to the mobile operator for today’s 2G/3G/4G networks, it is a stepping stone on the road to LTE-Advanced and 5G networks where advanced cell coordination techniques are required. By enabling mobile fronthaul services, HGC is helping mobile operators stay at the forefront of mobile technology and ultimately advancing mobile consumers’ experiences.

It is exciting to be one of the first operators in the world to announce a wholesale mobile fronthaul service. We are thrilled to be leading what we expect will be global adoption of C-RAN and fronthaul technology.

If you get a chance to come to Hong Kong in the near future, you could very well experience the benefits of HGC’s new mobile fronthaul service and our new network. I trust you’ll enjoy both Hong Kong and the mobile service you receive!

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This guest blog was written by Byron Chiang, Chief Technology Officer of Hutchison Global Communications. Infinera thanks him for his contribution.