Huawei Technologies Co., Ltd. ("Huawei") has recently announced a 1588v2-compliant DSL time synchronization prototype, a prototype whose time synchronization accuracy has achieved the GPS level. This event marks a significant technological breakthrough in the DSL arena and will present a more cost-effective mobile backhaul choice for mobile operators worldwide to build out their 3G/4G networks, as this technological breakthrough can utilize the widely deployed copper cables and overcome GPS deployment constraints. Moreover, by using this technological breakthrough, the deployment costs of 3G/4G services may be further reduced and end users are thus likely to experience 3G/4G services for which they are yearning for quickly and at a lower cost. 

1588v2: mainstream time synchronization technology in 3G/4G era

When a mobile subscriber switches from one base station to another in a mobile network, precise time synchronization is required; therefore, high-accuracy time synchronization is crucial to mobile communications. Most of next-generation mobile network technologies, including CDMA2000, TD-SCDMA, FDD-LTE, and TDD-LTE, also place high requirements on highly precise time synchronization. Nowadays, deploying small-sized and distributed mobile base stations in the 3G/4G networks is the industry's mainstream trend and the microcell base stations and LTE base stations are also burgeoning. Facing this new trend, operators will be burdened with overwhelmingly large 3G/4G deployment costs if the original practice of embedding GPS into bases stations is used.  

1588v2, as known as Precision Time Protocol (PTP), is a packet-based time synchronization technology standardized by the IEEE. This technology directly uses the existing service transmission channel and requires no GPS embedded on the base stations, thereby effectively addressing the issues facing GPS clock synchronization, such as high investments and difficult installation. Moreover, this technology has won wide recognition throughout the industry and has been agreed on as a crucial technology for network evolution to 3G/4G from 2G.

Huawei: turning the 1588v2-compliant DSL into reality

The 1588v2 protocol, originally formulated by the IEEE, takes into consideration only the symmetric models during the formulation of the time synchronization algorithm specified in the protocol. Thus, asymmetric transmission technologies such as DSL cannot effectively support the 1588v2 protocol. Operators have to be constrained by limited backhaul modes when using the 1588v2 technology. This triggers a great concern to operators who have deployed a great amount of DSL lines, as they sigh over their inability to maximize the invested DSL resources and may face repeated investments.

The industry has been persistently pursuing the backhaul of mobile base stations over the widespread DSL lines. Over the past few years, plenty of technical breakthroughs have been made in terms of line bonding, bandwidth improvement, and quality stabilization, and all these have greatly heightened the DSL-line-based mobile backhaul. However, high-accuracy time synchronization over DSL lines remains a still tricky hurdle, and no constructive mobile backhaul solutions in this regard have ever been proposed for the 3G/4G networks. Huawei this time, leveraging its proprietary algorithm, overcomes the technical difficulty associated with how to apply 1588v2 into the asymmetric DSL lines, which marks a milestone for transmitting full services over DSL lines. The prototype released by Huawei is proven in tests to have achieved the time synchronization accuracy of GPS level.     

Huawei's continuous innovations: leading DSL into the full-service access era

Over many years, Huawei has been a great contributor to the advancement of the DSL field. As early as 2001, Huawei took the lead in introducing IP into the access network, progressing the development of the IP DSLAM. In 2003, Huawei pioneered the worldwide mass market applications of ADSL2+ and fueled the triple play video era. Another historical moment was in 2006 when Huawei successfully set up the world's first large-scale commercial VDSL2 network, leading the triple play into a high-definition (HD) era for the first time. The year of 2009 was also a significant year for Huawei, as Huawei unveiled advanced DSM solutions and led DSL into an ultra-broadband era with broadband rate increased. Nowadays, Huawei's breakthrough in high-accuracy time synchronization over DSL lines this time is a milestone for full services over DSL lines and embraces a DSL-based full service era.

In terms of mobile backhaul, Huawei is the only supplier in the industry with 1588v2 high-accuracy time synchronization implemented over any media such as optical fiber, microwave, and copper wire. Huawei's mobile backhaul solutions have won wide recognition from industry-leading operators, and have already been servicing leading operators including China Mobile, Vodafone, and Telefónica.

Yang Zhirong, president of Huawei’s Access Network Product Line stated, "Huawei persistently makes innovations and sustains vitality in the DSL area, with a goal to help Huawei's customers succeed. This prototype released this time, a significant technical breakthrough in DSL, is one of Huawei's innovative DSL achievements. It will help operators quickly deploy 3G/4G services by using the commonly used broadband access technologies. This also echoes Huawei's mission, that is, helping operators make full use of their existing resources and avoid waste of resources, thus maximizing the network value for them."

source:c114en