The problem can be formulated as follows: Subject to: Such a dynamic wavelength sharing among ONUs is feasible because passive splitters are deployed at the RN, which is subject to power loss.Īssume that upstream traffic and downstream traffic are symmetric There are n ONUs in a PON and there are ω available wavelengths for transmission Let and B be the bandwidth of a wavelength Let K be the be the split ratio of a wavelength (K×ω > n) Let is the estimated traffic load of Let be 1 if is associated with wavelength Wavelength assignment is to assign n ONUs onto ω wavelengths such that the traffic load on each wavelength is less than B ONUs can dynamically share wavelengths by tuning to different wavelengths. This protocol is vulnerable to OLT failureĪ hybrid optical-wireless access network supporting load balancing with WDM/TDM PON as the optical sub network is proposed by Shaw. DBA: A centralized DBA protocol was proposed for inter-ONU communication where report messages are sent to the OLT and grant message is sent back to the ONUs from the OLT. A 2n×2n AWG, where n is the number of ONUs, is placed at the RN and two distributed fibers are connected to each ONU in such architecture, Based on the cyclic property of AWG, direct inter-ONU communication can be implemented.Ĩ Related work If two ONUs are connected to the same port of the AWG router to share wavelength for inter-ONU communication, they can not receive signals from each other since the wavelength they use to transmit inter-ONU traffic can not be routed to the port they are connected to. WDM/TDM PON architecture for efficient support of direct inter-ONU communication Wavelength assignment (and traffic grooming) in the optical sub network Dynamic Bandwidth Allocation (DBA) protocol supporting inter-ONU communication Dynamic egress ONU selection and routing in WMNs SimulationĬonventional PONs implement inter-ONU communication by sending the traffic from the source ONU to the OLT, which then sends it back to the destination ONU This implementation, suffers from OEO conversion delay and round-trip transmission delay Some PON architectures are developed to support such communication by broadcasting optical signals from one ONU to all ONUs through star coupler (SC) which is deployed at the remote node (RN) Such designs cause large power loss and can only be applied to TDM PONħ Related work A WDM EPON is proposed that supports direct inter-ONU communication, the transmission cycle is divided into two sub-cycles, one for upstream transmission, the other for inter-ONU communication Zaho has developed a novel WDM PON with internetworking capability. Wireless access can support flexible and ubiquitous communication in small community areas with a low deployment cost However, interference and low bandwidth limit wireless network’s deployment scalability A FiWi access network consists of a wireless sub network as the front end and an optical sub network as the back endĤ Introduction The FiWi must be able to efficiently support upstream, downstream, and peer-to-peer communications The integration of PONs and WMNs in FiWi access networks provides an opportunity to reduce the impact of interference on the network throughput The FiWi can potentially reduce the delay for some p2p communications since the transmission in the PON network can be much faster than that in the multi-hop wireless network.ĥ Agenda Related work and preliminary knowledge 1 FiWi Integrated Fiber-Wireless Access NetworksĢ Introduction FiWi access networks introduce wireless-optical-wireless communication FiWi access networks enable traffic to be sent from the source wireless client to an ingress ONU, then to the egress ONU close to the destination wireless client, and finally delivered to the destination wireless client FiWi supports direct inter-ONU communication in the optical sub networkģ Introduction Optical access provides huge bandwidth, but it is costly to achieve deep fiber penetration.
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