FTTH Access Network Solution
FTTH Access Network Solution
Under the background of "Broadband China" strategy and Country’s “Triple Play“ strategy, CATV network who is focusing on video business, is facing serious threats of telecom IPTV and Internet OTT TV. At the end of 2014, the number of FTTH network covering users reaches around 200 million. In 2015, China's broadband strategic goal is to add 80 million new FTTH households, to promote a batch of cities to take the lead in becoming all-fiber cities, as well as add 40 million new FTTH broadband subscribers. If CATV Operators want to win in the competition, firstly they need to ensure the advantages of broadcasting and live broadcasting of high-definition HD TV, Ultra high-definition TV, and do interactive video business and broadband Internet business, to break through 100 Mbps broad band, which asks them to do FTTH wide deployment right now.
Three Waves with One Fiber to Home
Schematic Diagram of Three Waves with One Fiber to Home
In the three waves with one fiber solution, after 1550nm optical signal of broadcasting network and data duplexing signal (1310nm upstream, 1490 downstream) sent by EPON equipment pass DWDM equipment, broadcasting optical signal and data duplexing signal are combined in one fiber physical channel. Being transmitted and optical split by all levels of ODN devices, finally they are delivered to users' houses. Inside users' houses, broadcasting TV signal and data duplexing signal are separated by home gateway ONU and separately sent to cable TV set top box and network terminals to realize service.
Advantages:
Port to Port Management
As network structure of three waves with one fiber is port to port, it is convenient to manage users’ terminal equipment. Network management staff can realize long-distance business service fulfillment, breakdown maintenance and service turnoff.
Cost Effective of ODN
As broadcasting TV signal and data duplexing signal are transmitted in one physical fiber, this solution reduces lots of building cost of ODN network splitters and fiber core resource from secondary headend to users.
In the three waves with one fiber solution, it should be noticed that during transmission of EPON, data IDLE code of 1490 downstream will cause single frequency interference to 1550nm downstream CATV signal at 62.5 MHz. Meanwhile, as frequency of 1550nm downstream CATV signal is high, non-linear interference to 1490nm data signal should also be considered. So WDM with over 35 dB wavelength isolation should be selected. So far, the cost of three waves with one fiber is high, for users who only open broadcasting service, terminal equipment of WDM + optical receiver should be provided. Thus, three waves with two fibers solution is recommended before cost of WDM + ONU + optical receiver terminal is reduced.
Three Waves with Two Fibers to Home
Three waves with two fibers solutions is that EPON data optical signal and CATV optical signal are separately transmitted in different fiber cores and delivered to users' houses by different physical transmitting channels. After getting into users’ houses, CATV optical signal is transformed to be RF signal by FTTH indoor receiver and then sent to digital set top box to realize service. EPON data duplexing signal is sent to network equipment to realize service by passing FTTH indoor ONU.
Advantages:
No Wavelength Interference
In three waves with two fibers FTTH solution, broadcasting optical signal and data duplexing signal are transmitted in two individual physical fiber channels, to avoid wavelength interference.
Low Cost of User Terminal
Compared with three waves with one fiber solution, three waves with one fiber solution reduces lots of DWDM equipment cost of user terminal.
High Reliability
No outdoor active equipment, high reliability, reducing lots of cost of operation, maintenance and power.
Disadvantage:
Compared with coaxial + single fiber and three waves with one fiber, construction cost of ODN is the highest.
Conclusion:
Three waves with two fibers solution is recommended before the cost of three waves with one fiber is reduced. It will increase cost of trunk optical cable, optical distribution cable, leading-in optical cable, splitter, manual melting, however, increasing cost of ODN per user is much lower than terminal cost of three waves with one fiber. So far, three waves with two fibers solution is the one-step, advanced, most reliable, most cost effective FTTH solution. So, three waves with two fibers solution is recommended to realize FTTH network construction for new-built community. This solution is presented according to three waves with two fibers.
