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Project Report on
WDM/TDM-PON
Presenter: Wen GuInstructor: Dr. Samuel Cheng
Outline
z Introduction
z TDM-PON
zWDM-PON
zWDM/TDM-PON
z References
IntroductionLong haul network
z Since the invention of WDM/DWDM, large amount of fiber have deployed all over the backbone network
z Bandwidth grows significantly
z Greatly surpassed the demand of global user.
Access network
z Stay in the phase of copper wires
z xDSL and cable modem provid much higher transmission speed compared to dial up
z There is a trade-off between bandwidth and loop length
z As the convergence of data, voice, and video traffic, the bandwidth of copper wires restrict the higher data rate
z It is unavoidable that fiber will replace traditional copper wires in access network
Figure 1. xDSL Configuration
TDM-PON
z TDM-PON(Passive Optical Network) has emerged as a promising technology to replace conventional access network.
z Point to multipoint (P2MP) topology without any active components from CO to the user.
Figure 2. PON Architecture
PON EvolutionITU-T G.983
ATM-PON (APON)
z The first Passive optical network standard
z Established in the early 90s last century
z Based on ATM
z Mainly developed in Germany
z Typical data rate: 54 Mbps to 155 Mbps
Broadband PON (BPON)
z Support 622 Mbps
IEEE 802.3ah
Ethernet PON (EPON)
Completed in2004 as part of the first mile project
Based on Ethernet protocol
Data rate: 1.25 Gbps in both downstream and upstream direction
ITU-T G.984
Gigabit PON (GPON)
2.5 Gbps in downstream direction and 1.25 Gbps in upsteam direction
10-GEPON
In early 2006, EPON also began to work on 10 Gigabit/second EPONstandard
Figure 3. History of PON development
EPON Architecture
Figure 4. Ethernet Frame format in EPON
Figure 5. EPON Architecture
Evaluation of TDM-PON
Security issues
z Broadcast nature Bandwidth sharing
z each user could get is also diminished.
Short transmission distance
z Due to the fact that many users share an optical splitter
Complicated bandwidth allocation protocol
z The protocol needed to implement TDM and dynamically allocate bandwidth is very complicated and not easy to realize.
WDM-PON
Dedicated wavelength from OLT (CO) to ONU
Point-to-point topology
Remote Node (RN) replace splitterMultiplexer / demultiplexer
Each user is equipped with a transmitter and receiver
WDM-PON Architecture
Figure 6. WDM-PON Architecture
Evaluation
Pros:
Huge bandwidth and guaranteed Quality of Service (QoS)
Safe and good security
Longer transmission distance
Reduce the complexity
Easier to implement compared to TDM-PON.
Cons:
Only but pretty huge issue: cost
z Gbps rates of WDM-PON is too large for a single user
z Big portion of the bandwidth of one wavelength is wasted
z Large number of wavelengths needed
z more fibers
z more transceivers
z build such architecture as well as the maintenance fee
Thus, unless
z Drop of cost of components
z Component installation fee large
z Increase of bandwidth demand
z Actually impractical to implement WDM-PON in at least a few years
So, what can we do?
WDM/TDM-PON
z Compromise between WDM-PON and TDM-PON
z Combine the advantages of Both technologies
z First WDM, then TDM
z One wavelength per ONU
z Several NTs (Network Terminal) connected to one OUN
z Each NT serves one or more users
z Traffic from/to NT are time multiplexed
Figure 7. WDM/TDM PON Architecture (Downstream)
Figure 7. WDM/TDM PON Architecture supporting two topology
Conclusionz Unlike EPON which has already been applied and deployed
z WDM/TDM-PON now is just a proposal and active research area
z Not specified as any standard yet
But we believe
z WDM/TDM-PON combines the advantages of TDM-PON and WDM-PON
z Further research of the protocol and architecture
z WDM/TDM-PON has enormous potential market.
References[1] Stamatios V. Kartalopoulos, Next generation hierarchical CWDM/TDM-PON network
with scalable bandwidth deliverability to the premises, Optical Switching and Networking, Volume 2, Issue 3, November 2005, Pages 163-175.
[2] Glen Kramer and Gerry Pesavento, Ethernet Passive Optical Network (EPON): Buildinga Next-Generation Optical Access Network, IEEE Communication Magazine, Feb. 2002, pp. 66-73.
[3] Lee, C.-H.; Sorin, W. V.; Kim, B. Y., Fiber to the Home Using a PON Infrastructure, Lightwave Technology, Journal of Volume 24, Issue 12, Dec. 2006 Page(s):4568 4583.
[4] Sierra, A.; Kartalopoulos, S.V., Evaluation of Two Prevalent EPON Networks Using Simulation Methods, Telecommunications, 2006. AICT-ICIW '06. International Conference on Internet and Web Applications and Services/Advanced InternationalConference on 19-25 Feb. 2006 Page(s):48 48.
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