With the major carriers "Broadband speed", "Light of Copper"
project extensively, The future will be a multimedia broadband services,
video on demand, interactive games as the main feature, high-bandwidth,
integrated operators will be judged promoted by the merits of the
standard broadband products.
Under the broadband Fiber Optic Network
in the trend, PON technology has become the world's attention to
various telecom operators hot technology is one of the operators to
implement "broadband speed", "Light of Copper" engineering technology
base. Wheter EPON, or GPON, which provides only for the uplink and
downlink bandwidth of 1G or 2G, but with the current interactive network
TV (IPTV), high definition television (HDTV), online games, video
services and other large flow, a large broadband business development
and popularization of the per-user bandwidth demand is expected to grow
every three years, a trend of increasing magnitude, from the future
operator of long-term trends, per-user bandwidth demand will be 50-100
Mbit/s between. This way, EPON and GPON are unable to meet the future
needs of the development of broadband services, the existing PON port
bandwidth, there will be a bottleneck. Therefore, ITU-T, FSAN, IEEE and
other major standards organizations begin the next generation of PON
technology research.
Similar to 1G PON Technology,
10G PON and 10G EPON technology is still divided into two camps 10G
GPON. In IEEE 802.3av 10G EPON standards, maximizing follows the usual
IEEE 802.3ah content, with good upward compatibility.
>> 10G PON technical analysis
Recalling
the history of PON technology can be found in each of the PON
technology from birth to the end of the day have to go through
large-scale commercial development of technical standards, the relevant
chip and optical module development, test and production, the creation
of experimental and commercial bureau 4 stages of deployment, which
lasted five years or so, each one of which will go through several
stages of development of the argument.
* Standardization Advances
Standards
are mature is the precondition of judging whether a technology have
lead to condition. At this stage, including IEEE, ITU-T, FSAN and number
of ongoing international standardization organizations 10G EPON and 10G
GPON standards development work of two technologies. Overall, the 10G
EPON technology start time earlier than 10G GPON, therefore, the current
standardization process of 10G EPON slightly faster than 10G GPON.
a. 10G EPON
Technologies
with 1G EPON, 10G EPON standards are mainly led by the IEEE to
complete. IEEE organization at September 12, 2009 released the 10G EPON
international standards 802.3av, this standard focuses on the physical
layer 10G EPON technology research, followed the tradition of 1G EPON
MPCP protocol, the 1G EPON downlink bandwidth increases to 10G at the
same time, to ensure that the operator of the original investment is not
compromised and 10G EPON smooth upgrade, IEEE 802.3av standard defines
and 1G EPON ONU coexist in the same ODN network of 10G EPON ONU standard parameters.
Further,
in IEEE 802.3av standard, the physical layer defines two parameters:
one asymmetric model, which 10G rate downlink and 1G rate uplink; other
is symmetrical pattern, i.e. uplink rate and downlink rate are both 10G.
Asymmetric mode can be considered as a transitional form symmetrical
patterns, in the early less demand for upstream bandwidth and cost
sensitive applications, you can use an asymmetric form. With the
development of business and technology progress, will be gradually
transition to a symmetrical mode.
b. 10G GPON
According
to ITU-T Study plans, NGPON will experience two standard phases: the
first phase is the coexistence with GPON, GPON ODN heavy use of XG-PON,
which in turn contains the uplink and downlink phase XG-PON1 asymmetric
and symmetric XG-PON2 two kind of model; Second stage is completely new
ODN's NGA2. High concern Wavelength Division Multiplexing - Passive
Optical Network (WDM-PON) technology areas belong to the second stage,
it was adopted in a fiber access network using multiple wavelengths to
achieve the expansion, but the burst mode CWDM, colorless ONU
transceivers, tunable WDM devices and some difficult technology can not
break, WDM-PON is still at the proof stage.
In
the end of September 2009 meeting of the ITU-T SG 15 plenary session, Q2
Working Group officially launched the NG-PON standard text in the first
stage, that overall demand for next-generation PON systems (G.987.1)
and Physical Layer Specifications (G.987.2), and also developed in
mid-2010, publishing transmission convergence layer (G.987.3) and
management control interface (G.988) standards program.
* Technical Parameters
Wheter
IEEE 802.3av, or ITU-T G.987 protocol suite, all relevant technical
parameters for 10G PON physical layer index, optical power budget to
make a detailed definition. However, due to the two major standards
organizations considered the starting point, the technical indicators
are also some differences.
a. 10G EPON
There are four key points of 10G EPON technology:
1.
Defines six 10G EPON optical power budget, in view of the asymmetric
mode PRX10, PRX20 and PRX30 as well as for symmetric mode PR10, PR20 and
PR30, these six kinds of optical power budget model is basically to
meet the construction needs of the service provider network;
2.
10G EPON technology in achieving the 1G EPON conventional multi-point
control protocol layer (MPCP) based on the forward compatibility, also
extended the original message type, for reporting optical terminal
equipment (OLT), ONU Optical Transceiver Module switch time to meet the 10G EPON system requirements;
3.
10G EPON uses (255, 223) Forward Error Correction (FEC) encoding
method, the encoded with FEC coding for the same strain of 1G EPON, but
its strong support 10G EPON coding gain can lower the sensitivity of the
optical receiver;
4. 10G EPON uplink and
downlink wavelength for the re-planning, downlink using 1268-1280nm
wavelength, then reuse the original uplink of 1G EPON 1575-1580 nm
wavelength, the wavelength in order to avoid conflicts, 10G EPON uplink
only use time division multiple access (TDMA) manner.
b. 10G GPON
Has
been released G.987.1 standard that defines 10G GPON system's overall
technical requirements and system architecture, clearly put forward the
10G GPON system to ensure good QoS, based on the traditional telecom
services to fully support all emerging businesses and the same time,
also provides dynamic Bandwidth Allocation (DBA) algorithm, energy
saving, authentication and encryption related content to inherit the
original 1G GPON technology; The G.987.2 is the focus of standardized
10G GPON physical layer parameters, including downlink rate, ODN power
budget, splitting ratio, up and down the line wavelength range and line
coding, etc., although down the line of 10G EPON same wavelength range
and 10G EPON, GPON but due to the wavelength with 1G is not conflict,
therefore, 10G GPON uplink and downlink are used wavelength division
multiple access (WDMA) manner.
* Industrial chain development
A
complete industrial chain, including chip PON, optical modules and
equipment three links. If to analysis PON industry chain, it need to
start from the three links, analysis of every link current development
status and future development trend.
Overall,
10G EPON and 10G GPON is currently not reach the requirements of
large-scale commercial applications, although some equipment
manufacturers have recently introduced a 10G EPON or 10G GPON products,
and with operators, the creation of some experimental inning, but still
in the laboratory testing phase, is still some distance away from the
large-scale commercial.
>> Conclusion
No comments:
Post a Comment