What is a Microgrid
For the convenience of operation, maintenance and management, the fiber optic access network in the city is usually constructed in sections by region.
The integrated service access area is divided in the metropolitan area, and the microgrid is further divided in the integrated service access area.
The trunk optical cable line is usually constructed in the integrated service access area as a unit, and the introduction optical cable line is usually constructed in the microgrid as a unit.
The fiber optic access service in the microgrid is converged to the distribution optical exchange through the introduction optical cable, and then connected to the trunk optical exchange through the distribution optical cable, and converged to the aggregation point through the trunk optical cable.
Generally speaking, a microgrid is a coverage area of ​​a wiring optical crossover. The boundaries of a microgrid are generally clear, and the coverage area is usually relatively fixed. The integrated service access area completes the full coverage of the optical fiber access network in the entire area through microgrids.
Microgrid Division
The division of microgrids is mainly related to factors such as the coverage capacity of the distribution optical intersection, natural boundaries such as municipal roads, and the construction conditions of the distribution and introduction of optical cable lines.
Coverage Capacity of the Wiring Optical Intersection
For the households that can be covered by the optical distribution exchange, please refer to the article “What is the network coverage capacity of a optical distribution frame?” When the micro grid is a residential community, the coverage area of ​​the optical distribution exchange can be estimated based on the volume ratio of the community.
Considering resource utilization and grid scalability, the capacity of urban optical distribution connection should be mainly 576 cores.
288 cores can also be used in buildings with smaller business demands and low-density scenarios. It is not advisable to use optical distribution connection with less than 288 cores. The size of the micro grid should be 50% to 100% of the coverage capacity of the distribution optical cross-connection.
Coverage Area Boundaries
Natural boundaries such as municipal roads, rivers, and mountains in the city divide the city into independent “blocks”.
Since the incoming optical cables are only laid within the microgrid, these natural boundaries that are not conducive to the passage of optical cables become ideal dividing lines for microgrids, and dividing microgrids according to “blocks” also makes the division of microgrids simple.
A “block” can be further divided into one or more microgrids based on the demand for optical fiber ports for potential services within its coverage area.
For residential and public buildings with internal fiber access networks built by developers, when planning microgrids, it is not necessary to know the specific construction of the internal fiber network, but only the coverage area. When dividing microgrids within a “block”, the area should be considered as an independent microgrid.
A building or building complex used by the same unit (such as a school, hospital, hotel, etc.) is just a dedicated line user for the operator and has little demand for fiber ports, and should not be treated as an independent microgrid.
Construction Conditions of Optical Cable Lines
The introduction of optical cable lines within microgrids is generally built inside residential areas, commercial and office buildings, etc., and usually requires the consent of relevant owners before implementation.
Therefore, the wiring and introduction of optical cable lines can only be carried out after the operator coordinates with one or several owners.
Each batch of fiber access projects covers mostly scattered areas, such as one or several residential areas, one or several commercial buildings, etc. The demand for fiber ports in these scattered areas is usually less than 50% of the capacity of a distribution optical exchange.
In most cases, they can be merged with the surrounding microgrids, but in actual projects, they are often built into independent microgrids. This has led to the current situation that the coverage of microgrids in the existing network is generally small.
Low-density Areas
In areas with low user density, such as industrial parks and urban suburbs, the number of users in each block is usually only a few to dozens. Municipal roads are not an obstacle to laying optical cables, but have become the main channel for laying optical cables. In this scenario, it is not appropriate to divide microgrids by blocks.
Microgrids can be divided according to the specific distribution of users, with municipal roads as the main line and user-free areas as the boundaries.
In low-density areas, if the size of the microgrid is determined by the network coverage capacity of 288 cores optical distribution, the coverage area of ​​the microgrid may be large (more than 1.0 square kilometers).
In this case, the coverage area of ​​the micro-grid can be limited to within 10% of the area of ​​the integrated service area based on the area of ​​the integrated service area.
Microgrid Coverage Radius
In a microgrid, except for a small number of dedicated data lines, most users are installed through fiber splitter distribution boxes. The size of the microgrid coverage radius rarely affects the difficulty of user installation. Therefore, it is meaningless to limit the coverage radius of the microgrid to 150 meters, 200 meters or 300 meters in different scenarios.
For example, in some multi-story residential communities with narrow terrain, the distance between users and distribution optical cross connections often exceeds 500 meters. While in industrial parks, the distance between users and distribution optical cross-connections exceeds 1000 meters is more common (in some industrial parks in the current network, the coverage radius of the distribution optical cross connection is too small because no introduction section optical cable and fiber splitter box are built between the distribution optical cross-connection and the user).
In different scenarios, the radius or coverage area of ​​microgrids can vary greatly, and comparison is only meaningful in the same or similar scenarios.
Number of Optical Crossovers in Microgrids
Generally, a microgrid has only one optical distribution switch.
However, when the original microgrid’s optical distribution switch capacity is insufficient and needs to be expanded on site, or when the service boundaries of the two optical distribution switches are unclear (such as different units in a house are covered by different optical distribution switches), a microgrid may be covered by two optical distribution switches. This situation should be avoided as much as possible during network planning.
Challenges of Microgrid Planning
After years of construction, microgrids in cities have basically achieved full coverage of fiber optic access services. However, microgrid coverage is generally plagued by problems such as duplicate coverage, too small coverage (more than 15 optical crosses per square kilometer), missing coverage, and blurred coverage boundaries, which have brought considerable trouble to the construction, maintenance, and installation of the network.
However, the rational planning of microgrids is far more complicated than expected.
Due to the limited management capabilities of operators for sub-resources such as optical cables, they can only count the number of optical crossovers for wiring, but cannot understand the specific coverage of each microgrid. This greatly reduces the rationality of microgrid planning results.
Even if the current network situation of a block is completely clear, when planning a microgrid, at least the following information in the block needs to be investigated:
- Optical cable laying conditions (pole and pipeline resources);
- Which buildings are shared by three networks;
- The number of floors and households per unit in residential communities that are not shared by three networks;
- The distribution of users in public buildings that are not shared by three networks;
- The distribution of private lines, broadband, indoor distribution, macro base stations and other services in the block. The workload of investigating this information in the planning stage is huge, but the significance is limited.
The figure below is a microgrid planning map of a city (partial).
Summary and Suggestions
Most of the contents that need to be investigated in microgrid planning are related to engineering design and network optimization.
If the planning of microgrids is adjusted to the design stage, the division of micro-grids, the design of new fiber optic access projects and the optimization of access optical cable lines can be combined according to the integrated business access areas and reflected in the design in a unified manner, it may be a better choice.
If you encounter complex terrain during microgrid network installation and need to customize special structural fiber optical products, the Bonelinks team can not only provide the most suitable passive optical communication product design based on your actual construction conditions, but also provide on-site technical support to help your project succeed.
