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NE40E-M2 V800R010C10SPC500 Configuration Guide - System Management 01

This is NE40E-M2 V800R010C10SPC500 Configuration Guide - System Management
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Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
Overview of 1588v2

Overview of 1588v2

Purpose

Data communications networks do not require time or frequency synchronization and, therefore, Routers on such networks do not need to support time or frequency synchronization. On IP radio access networks (RANs), time or frequency needs to be synchronized among base transceiver stations (BTSs). Therefore, Routers on IP RANs are required to support time or frequency synchronization.

Frequency synchronization between BTSs on an IP RAN requires that frequencies between BTSs be synchronized to a certain level of accuracy; otherwise, calls may be dropped during mobile handoffs. Some wireless standards require both frequency and time synchronization. Table 9-1 shows the requirements of wireless standards for time synchronization and frequency accuracy.

Table 9-1 Requirements of wireless standards for time synchronization and frequency accuracy
Wireless Standards Requirement for Frequency Accuracy Requirement for Time Synchronization
GSM 0.05 ppm NA
WCDMA 0.05 ppm NA
TD-SCDMA 0.05 ppm 3us
CDMA2000 0.05 ppm 3us
WiMax FDD 0.05 ppm NA
WiMax TDD 0.05 ppm 1us
LTE 0.05 ppm In favor of time synchronization

Different BTSs have different requirements for frequency synchronization. These requirements can be satisfied through physical clock synchronization (including external clock input, WAN clock input, and synchronous Ethernet clock input) and packet-based clock recovery.

Traditional packet-based clock recovery cannot meet the time synchronization requirement of BTSs. For example, NTP-based time synchronization is only accurate to within one second and 1588v1-based time synchronization is only accurate to within one millisecond. To meet time synchronization requirements, BTSs need to be connected directly to a global positioning system (GPS). This solution, however, has some disadvantages such as GPS installation and maintenance costs are high and communications may be vulnerable to security breaches because a GPS uses satellites from different countries.

1588v2, with hardware assistance, provides time synchronization accuracy to within one micro second to meet the time synchronization requirements of wireless networks. Thus, in comparison with a GPS, 1588v2 deployment is less costly and operates independently of GPS, making 1588v2 strategically significant.

In addition, operators are paying more attention to the operation and maintenance of networks, requiring Routers to provide network quality analysis (NQA) to support high-precision delay measurement at the 100 us level. Consequently, high-precision time synchronization between measuring devices and measured devices is required. 1588v2 meets this requirement.

1588v2 packets are of the highest priority by default to avoid packet loss and keep clock precision.

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Updated: 2019-01-02

Document ID: EDOC1100058392

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