According to relevant data, the proportion of global FTTH/FTTP/FTTB broadband users will reach 59% in 2025. Data provided by market research company Point Topic shows that this development trend will be 11% higher than the current level.
Point Topic predicts that there will be 1.2 billion fixed broadband users worldwide by the end of 2025. In the first two years, the total number of global broadband users exceeded the 1 billion mark.
Approximately 89% of these users are located in the top 30 markets worldwide. In these markets, FTTH and related technologies will mainly grab market share from xDSL, and the xDSL market share will drop from 19% to 9% during the forecast period. Although the total number of users of fiber to the building (FTTC) and VDSL and DOCSIS-based hybrid fiber/coaxial cable (HFC) should climb during the forecast period, the market share will remain relatively stable. Among them, FTTC will account for approximately 12% of the total number of connections, and HFC will account for 19%.
The emergence of 5G should inhibit fixed broadband applications during the forecast period. Before 5G is actually deployed, it is still impossible to predict how much the market will be affected.
This article will compare Passive Optical Network (PON) access technology and Active Optical Network (AON) access technology based on the characteristics of residential communities in my country, and analyze the advantages and disadvantages of its application in residential communities in China. , By clarifying several prominent problems in the application of FTTH access technology in residential districts in my country, a brief discussion on my country’s appropriate strategies for developing FTTH application technology.
1. Characteristics of my country’s FTTH target market
At present, the main target market for FTTH in China is undoubtedly the residents of residential communities in large, medium and small cities. Urban residential communities are generally garden-style residential communities. Their outstanding features are: high density of households. Single garden residential communities generally have 500-3000 residents, and some are even Tens of thousands of households; residential communities (including commercial buildings) are generally equipped with communication equipment rooms for the installation of communication access equipment and line handovers throughout the community. This configuration is required for telecommunications operators to compete with each other and integrate multiple telecommunications services. The distance from the computer room to the user is generally less than 1km; major telecom operators and cable TV operators have generally laid small core counts (usually 4 to 12 cores) optical cables to the computer rooms of residential quarters or commercial buildings; residential communication and CATV access in the community Cable resources belong to each operator. Another characteristic of my country’s FTTH target market is the existence of industry barriers in the provision of telecom services: telecom operators are not allowed to operate CATV services, and this status quo cannot be changed for a considerable period of time in the future.
2. Choice of FTTH Access Technology in my country
1) Problems faced by passive optical network (PON) in FTTH applications in my country
Figure 1 shows the network structure and distribution of an ideal passive optical network (Passive Optical Network-PON). Its main features are: optical line terminal (Optical Line Terminal-OLT) is placed in the telecom operator’s central computer room, and passive optical splitters are placed (Splitter). ) As close as possible to the optical network unit (Optical Network Unit——ONU) on the user side. The distance between the OLT and the ONU is equal to the distance between the telecom operator’s central computer room and the user, which is similar to the current fixed telephone access distance, which is generally several kilometers, and the Splitter is generally tens of meters to hundreds of meters away from the ONU. This structure and layout of PON highlights the advantages of PON: the entire network from the central computer room to the user is a passive network; a large amount of fiber optic cable resources from the central computer room to the user are saved; because it is one-to-many, the number of equipment in the central computer room is reduced and Scale, reducing the number of wiring in the central computer room.
The ideal layout of a passive optical network (PON) in a residential area: OLT is placed in the central computer room of a telecom operator. According to the principle that the Splitter is as close to the user as possible, the Splitter is placed in the floor distribution box. Obviously, this ideal layout can highlight the inherent advantages of PON, but it will inevitably bring about the following problems: First, a high-core number fiber optic cable is required from the central computer room to the residential area, such as 3000 residential quarters, calculated at a branch ratio of 1:16, Nearly 200-core optical fiber cable is required, but currently only 4-12 cores, it is very difficult to increase the laying of optical cable; second, users cannot freely choose the operator, can only choose the service provided by a single telecom operator, and it is inevitable that a single operator monopolizes The business situation is not conducive to the competition of multiple operators, and the interests of users cannot be effectively protected. Third, the passive optical distributors placed in the floor distribution box will cause the distribution nodes to be very scattered, resulting in very difficult allocation, maintenance and management. It is even almost impossible; fourth, it is impossible to improve the utilization of network equipment and its access ports, because within the coverage of a single PON, the user access rate is difficult to achieve 100%.
The realistic layout of the passive optical network (PON) in the residential area: OLT and Splitter are both placed in the computer room of the residential area. The advantages of this realistic layout are: only low-core fiber optic cables are needed from the central computer room to the residential area, and the existing optical cable resources can meet the needs; the access lines of the entire residential area are wired in the computer room of the residential area, allowing users to freely choose different telecom operators. For telecom operators, the network is very easy to assign, maintain and manage; because the access equipment and patch panels are in the same cell room, it will undoubtedly significantly improve the port utilization of the equipment, and the access equipment can be gradually expanded according to the increase in the number of access users. . However, this realistic layout also has its obvious shortcomings: First, the network structure of discarding PON is the biggest advantage of passive networks, and the central computer room to the user network is still an active network; secondly, it does not save fiber optic cable resources because of PON; , PON equipment has high cost and complex network structure.
In summary, PON has two contradictory sides in the FTTH application of residential quarters: According to the ideal network structure and layout of PON, it can certainly give play to its original advantages: the entire network from the central computer room to the user is a passive network, which saves a lot of central computer room To the user’s fiber optic cable resources, the number and scale of equipment in the central computer room are simplified; however, it also brings almost unacceptable shortcomings: a large increase in the laying of fiber optic cable lines is required; the distribution nodes are scattered, and number allocation, maintenance and management are extremely difficult; users cannot freely choose Operators are not conducive to multi-operator competition, and the interests of users cannot be effectively guaranteed; the utilization of network equipment and its access ports is low. If the realistic layout of the passive optical network (PON) in the residential quarter is adopted, the existing optical cable resources can meet the needs. The computer room of the community is uniformly wired, which is very easy to assign, maintain and manage numbers. Users can freely choose the operator, which significantly improves Equipment port utilization, but at the same time discarded the two major advantages of PON as a passive network and saving fiber optic cable resources. At present, it must also endure the disadvantages of high PON equipment cost and complex network structure.
2) Choice of FTTH access technology for residential communities in my country-Point-to-point (P2P) access technology for Active Optical Network (AON) in residential quarters
Obviously, the advantages of PON disappear in high-density residential communities. As the current PON technology is not very mature and the equipment price remains high, we believe that it is more scientific and feasible to choose AON technology for FTTH access, because:
－Computer rooms are generally set up in the community;
-AON’s P2P technology is mature and low-cost. It can easily provide 100M or 1G bandwidth and realize seamless link with existing computer networks;
-There is no need to increase the laying of optical cables from the central machine room to the residential area;
－－Simple network structure, low construction and operation and maintenance costs;
-Centralized wiring in the computer room of the community, easy to assign numbers, maintain and manage;
-Allow users to freely choose operators, which is conducive to the competition of multiple operators, and the interests of users can be effectively protected through competition;
——The equipment port utilization rate is very high, and the capacity can be gradually expanded according to the increase in the number of access users.
A typical AON-based FTTH network structure. The existing low-core fiber optic cable is used from the telecom operator’s central computer room to the community computer room. The switching system is placed in the community computer room, and the point-to-point (P2P) networking mode is adopted from the community computer room to the user terminal. Incoming equipment and patch panels are uniformly placed in the community computer room, and the entire network adopts the Ethernet protocol with mature technology and low cost. AON’s point-to-point FTTH network is currently the FTTH access technology commonly used in Japan and the United States. Among the current 5 million FTTH users in the world, more than 95% use active switching P2P technology. Its outstanding advantages are:
－－High bandwidth: easy to realize stable two-way 100M broadband access;
-It can support Internet broadband access, CATV access and telephone access, and realize the integration of three networks in the access network;
－－Support the foreseeable new business in the future: videophone, VOD, digital cinema, remote office, online exhibition, TV education, remote medical treatment, data storage and backup, etc.;
－－Simple network structure, mature technology and low access cost;
－－Only the computer room in the community is an active node. Centralize the wiring of the computer room to reduce maintenance costs and improve the utilization of equipment ports;
-Allow users to freely choose operators, which is conducive to the competition between telecom operators;
-Effectively save the fiber optic cable resources from the central computer room to the community, and there is no need to increase the laying of fiber optic cables from the central computer room to the community.
We believe that it is more scientific and feasible to choose AON technology for FTTH access, because of the uncertainty in the development of PON standards and technologies:
-The standard has just appeared, with multiple versions (EPON & GPON), and the competition of standards is uncertain for future promotion.
－Relevant devices require 3-5 years of standardization and maturity. It will be difficult to compete with current Ethernet P2P devices in terms of cost and popularity in the next 3-5 years.
-PON optoelectronic devices are expensive: high-power, high-speed burst transmission and reception; current optoelectronic devices are far from being able to meet the requirements of producing low-cost PON systems.
-At present, the average selling price of foreign EPON equipment is 1,000-1,500 US dollars.
3. Pay attention to the risks of FTTH technology and avoid blindly requesting support for full-service access
Many users require FTTH to support all services, and simultaneously support broadband Internet access, cable television (CATV) access and traditional fixed telephone access, that is, triple play access, hoping to achieve FTTH access technology in one step. We believe that it is ideal to be able to support broadband Internet access, limited television (CATV) access and ordinary fixed-line telephone access, but in fact there are huge technical risks.
At present, among the 5 million FTTH users in the world, more than 97% of FTTH access networks only provide Internet broadband access services, because the cost of FTTH to provide traditional fixed telephone is much higher than the cost of existing fixed telephone technology, and the use of optical fiber to transmit traditional fixed The telephone also has the problem of telephone power supply. Although AON, EPON and GPON all support triple play access. However, the EPON and GPON standards have just been promulgated, and it will take time for the technology to mature. The competition between EPON and GPON and the future promotion of these two standards is also uncertain, and its point-to-multipoint passive network structure is not suitable for China’s high density. Residential area applications. Furthermore, EPON and GPON related devices require at least 5 years of standardization and maturity. In the next 5 years, it will be difficult to compete with the current Ethernet P2P devices in terms of cost and popularity. At present, opto electronic devices are far from being able to meet the low production requirements. Cost PON system requirements. It can be seen that the blind pursuit of FTTH full-service access using EPON or GPON at this stage will inevitably bring huge technical risks.
On the access network, it is an inevitable trend for optical fiber to replace various copper cables. However, optical fiber will completely replace copper cables overnight. It is unrealistic and unimaginable for all services to be accessed through optical fibers. Any technological progress and application are gradual, and FTTH is no exception. Therefore, in the initial development and promotion of FTTH, the coexistence of optical fiber and copper cable is inevitable. The coexistence of optical fiber and copper cable can enable users and telecom operators to effectively avoid the technical risks of FTTH. First of all, AON access technology can be used in the early stage to achieve FTTH broadband access at low cost, while CATV and traditional fixed telephones still use coaxial and twisted pair access. For villas, CATV access can also be achieved simultaneously through optical fiber at low cost. Second, there are industry barriers in the provision of telecom services in China. Telecom operators are not allowed to operate CATV services. On the contrary, CATV operators are not allowed to operate traditional telecom services (such as telephone), and this situation will be quite a long time in the future. The time cannot be changed, so a single operator cannot provide triple play services on the FTTH access network; again, since the life of optical cables can reach 40 years, while copper cables are generally 10 years, when copper cables are due to life When the communication quality declines, there is no need to lay any cables. You only need to upgrade the fiber optic equipment to provide the services provided by the original copper cables. In fact, as long as the technology is mature and the cost is acceptable, you can upgrade at any time. Optical fiber equipment, timely enjoy the convenience and high bandwidth brought by the new FTTH technology.
To sum up, the current choice of optical fiber and copper cable coexistence, using AON’s FiberP2P FTTH to achieve Internet broadband access, CATV and traditional fixed telephones still use coaxial and twisted pair access, which can effectively avoid the risk of FTTH technology At the same time, enjoy the convenience and high bandwidth brought by the new FTTH access technology as soon as possible. When the technology is mature and the cost is acceptable, and the industry barriers are eliminated, the fiber optic equipment can be upgraded at any time to realize FTTH full service access.
Post time: Apr-10-2021