With the development of telecom technologies and services, the high-rate services and applications such as video and data are increasingly enriched and the market competition is becoming increasingly fierce. In order to maintain the sustainable development of broadband access, meet the users’ demand for high-rate services, reduce maintenance costs and cope with market competition, China Telecom is actively implementing the strategic transformation of access networks, adopting new technologies, improving access bandwidth, and implementing broadband access Network upgrade, so as to fully realize by voice-oriented traditional basic operators to integrated information service provider’s business strategy transformation.
OLT deployment requirements
1. The deployment of OLT nodes should be centralized mainly to meet the coverage of integrated service area as the goal, combined with coverage, user distribution, pipeline resources, machine room installation conditions and other factors to determine, try to choose the center area of coverage, construction and maintenance convenience since Equity or long-term rental room, to ensure that the OLT node room location and long-term stability.
2.For areas in the integrated service area where there is no transmission or aggregation engine room or where one transmission convergence room in the area can not meet the service convergence requirements, the integrated access to the equipment room or the equipment room that uses the better conditions, solve.
3.The deployment of OLT devices should be deployed according to the principle of meeting the regional access requirements. For the purpose of predicting the service access needs within 1-2 years of the terrestrial service, you should give priority to the deployment of OLT devices (based on the device configuration and later expansion of the card according to the service requirements). The deployment principle is as follows:
a)Screening of its own transmission and convergence of equipment room, room conditions to meet the installation requirements of the engine room, according to business needs priority deployed 1-2 OLT equipment for the latter part of rapid business access for the reserve.
b)Screening suburbs transmission aggregation room, for the recent business needs of the engine room, but also give priority to the deployment of OLT equipment.
c)If there is no integrated service area where the equipment room and the OLT equipment room are converged, select an appropriate equipment room according to the service plan and install the OLT equipment to reserve the service for quick access.
OLT deployment method
There are two common OLT settings, one is centralized settings, one is decentralized settings.
Centralized setting means that one OLT device covers multiple user areas, such as residential areas, commercial areas, administrative areas and other user areas. This mode is mainly used in the construction of urban and township integrated service areas. The OLT equipment is placed in the computer room of the integrated service area and extended with trunk optical fiber cables to facilitate post-management and capacity expansion.
In a decentralized manner, the OLT is sinking into a single-user area and the user area is covered in a targeted manner. The OLT is mainly used in large-scale residential areas, clustering markets and dense rural areas. In this mode, OLT equipment is mainly used to sink to the base station equipment room of the area, and adopts the bare fiber connection to the PTN or OTN convergence layer. OLT equipment sunk deployment main application scenarios are as follows:
- large area: for more than 3000 households in large residential area
- Clustering Market: For industrial parks, commercial areas and other areas where more than 3,000 households are residents
- Rural: For the township integrated business area is not covered by the remote and densely populated villages in the region
OLT technical options
1.Splitting ratio setting: Select GPON technology to build PON network. The OLT equipment configures Class C + optical module. The total splitting ratio of set-off and WLAN services does not exceed 1 × 32, and the width of house type is 1 × 64. The splitting level does not exceed two Level (8 × 8 or 4 × 16).
2.Calculation of attenuation: When OLT planning and deployment, the first calculation of optical fiber link loss, the furthest district or village in the region should meet the system requirements of optical fiber link loss.
The GPON Class C + optical module system allows the maximum channel insertion loss to be calculated at 32 dB for fiber link loss calculations (Class C ++ optical modules are available in rural areas where long-distance coverage is required and the maximum channel insertion loss is calculated at 35 dB ), The total splitting ratio of 1 * 64, no more than two levels of splitting, the attenuation and attenuation values as shown in the following chart and the following table:
|Device||Optical splitter||Union (flange)||Direct melting point (connector box)||Optical fiber transmission||Maintain margin|
|Insert damage value||21 dB||0.5dB||0.1dB||0.4dB/km||2dB|
3.PON port planning: In principle, group customers and home customers can mix OLT equipment, but the group customers and family customers use the PON interface board is recommended to separate.
FTTB and FTTH / O can be mixed in the same OLT. However, for the convenience of VLAN planning, PON ports used by FTTH / O and FTTB are recommended to be separate. That is, one PON port is only used for FTTH / O access, or only for FTTB LAN) access.
In order to save room space, increase access density, requires the use of 16 PON board.
4.Optical module on the joint choice: OLT fiber optic cable through the uplink connection based on the reasonable choice of 10KM, 40KM optical module.
OLT site requirements
OLT site selection should take into account security, the engine room, pipelines and fiber optic cable building economy, as well as the maintenance of convenience and other factors.
Urban OLT should be mainly deployed in the “integrated service access area” in the room, all the deployment of rack-mounted OLT equipment; rural areas should generally be deployed to facilitate the user access to a relatively stable 10GE PTN aggregation node, where the township base station and Rural base stations with contiguous broadband needs in rural areas deploy rack-mounted OLT devices and small-box OLT devices can be deployed in base stations equipped with insufficient room.
Compared with the base station service, the broadband access service is very sensitive to the interruption time. Especially when the OLT capacity of the office equipment is getting larger and larger and more and more customers are accessing the OLT service, the failure of the OLT will cause the large number of customers to directly withdraw from the service, affecting Customer perception. Therefore, the OLT deploying the equipment room must be set at a stable home, with good conditions in the equipment room, easy access to the optical fiber cables, and easy access to the equipment room by the maintenance personnel to avoid being located in the equipment room of the base station where the relocation is frequent.
Epon OLT: FD1104SN,FD1108S,FD1208S,FD1216S