2) Cloud Radio Access Networks (C-RAN) and optical Mobile backhaul and fronthaul
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Increasing mobile data traffic due to the rise of both smartphones andtablets has led to high-capacity demand of mobile data network. Tomeet the ever-growing capacity demand and reduce the cost of mobilenetwork components, Cloud Radio Access Network (C-RAN) has emergedas a promising solution. In this network, the mobile operator s RemoteRadio Head (RRH) and Base Band Unit (BBU) are often separatedand the connection between them has very tight timing and latencyrequirements imposed by Common Public Radio Interface (CPRI) and3rd Generation Partnership Project (3GPP). This fronthaul connectionis not yet provided by packet based network. To employ packet-basednetwork for C-RAN fronthaul, the carried fronthaul traffic are needed toachieve the requirements of fronthaul streams. For this reason, the aimof this study was focused on investigating and evaluating the feasibilityof Integrated Hybrid Optical Networks (IHON) and Ethernet networksfor mobile fronthaul. The fronthaul requirements used to evaluate andinvestigate these networks were maximum End to End (E2E) latency,Packet Loss Ratio (PLR) and Packet Delay Variation (PDV). TransPacket AS (www.transpacket.com) develops a fusion switchingthat efficiently serves both Guaranteed Service Transport (GST) trafficwith absolute priority and packet switched Statistical Multiplexing (SM)best effort traffic. Dedicated wavelength is used to provide a deterministiccircuit switched transport and uses the leftover capacity on the wavelengthto transport the best effort traffic without affecting the absolute prioritypackets. We verified how the leftover capacity of fusion node can beused to carry the low priority packets and how the GST traffic can havedeterministic characteristics on a single wavelength by delaying it withFixed Delay Line (FDL). For example, for SM load=0.3 the added SM trafficincreases the 10GE wavelength utilization up to 89% without any lossesand with SM PLR=1E-03 up to 92% utilization. The simulated results and numerical analysis confirm that the PDVand PLR of GST traffic in IHON network and the PLR of High Priority(HP) traffic in Ethernet network meet the requirements of mobile fronthaulusing CPRI. However, the PDV of HP traffic meets the fronthaul networkwhen the number of nodes in the Ethernet network is at most four. Forboth IHON and Ethernet network, the number of nodes in the networklimits the maximum separation distance between BBU and RRH (linklength); for increasing the number of nodes, the link length decreases.Consequently, Radio over Ethernet (RoE) traffic should receive the priority and Quality of Service (QoS) only GST or HP can provide. On the otherhand, SM or Low Priority (LP) classes are not sensitive to QoS metricsand should be used for transporting time insensitive applications andservices. Furthermore, we numerically evaluated the performance of activeWavelength Division Multiplexing (WDM) when Optical TransmissionNetwork (OTN) encapsulation is employed and dedicated fronthaul net-works in terms of the maximum one-way latency and the maximum separation distance between BBU and RRH provided that the typicalvalues of BBU are known.