Abstract-Coupling MPLS Traffic Engineering on top of a wavelength-routed WDM layer offers great flexibility to operators to allocate traffic demands in their networks. In this paper we consider the problem of off-line joint configuration at both packet and optical layers. We consider time-variant offered traffic, and assume that the operator has knowledge of the traffic dynamics as a set of traffic matrices at different instants. A novel Mixed Integer Linear Programming (MILP) formulation is proposed, which takes in input this set of traffic matrices, and provide an optimal static configuration capable of accomodating the time-varying traffic. We provide a resolution strategy based on heuristics, and give numerical results for some sample cases. The proposed method is compared with a simple alternative approach for obtaining a single static solution, to show that our method utilizes much less resources. The solution under the proposed formulation is also compared with the set of solutions obtained by running distinct optimization problems at different instants, showing that the increase of resource is minimal. Hence our approach can provide a static configuration with about the same resources of a fully adaptable dynamical configuration.

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The increasing number of wireless devices, the high required traffic bandwidth, and power consumption will lead to a revolution of mobile access networks, which is not a simple evolution of traditional ones. Cloud radio access network technologies are seen as promising solution in order to deal with the heavy requirements defined for 5G mobile networks. The introduction of the common public radio interface (CPRI) technology allows for a centralization in BaseBand unit (BBU) of some access functions with advantages in terms of power consumption saving when switching off algorithms are implemented. Unfortunately, the advantages of the CPRI technology are to be paid with an increase in required bandwidth to carry the traffic between the BBU and the radio remote unit (RRU), in which only the radio functions are implemented. For this reason, a tradeoff solution between power and bandwidth consumption is proposed and evaluated. The proposed solution consists of: 1) handling the traffic generated by the users through both RRU and traditional radio base stations (RBS) and 2) carrying the traffic generated by the RRU and RBS (CPRI and Ethernet flows) with a reconfigurable network. The proposed solution is investigated under the lognormal spatial traffic distribution assumption. After proposing resource dimensioning analytical models validated by simulation, we show how the sum of the bandwidth and power consumption may be minimized with the deployment of a given percentage of RRU. For instance we show how in 5G traffic scenarios this percentage can vary from 30% to 50% according to total traffic amount handled by a switching node of the reconfigurable network.INDEX TERMS Radio access network, common public radio interface, 5G environment, statistical multiplexing gain.

The Centralized Radio Access Network (C-RAN) provides a valid solution to overcome the problem of traditional RAN in scaling up to the needed processing resource and quality expected in 5G. The Common Public Rate Interface has been defined to transport traffic flows in C-RAN and recently some market solutions are available. Its disadvantage is to increase by at least 10 times the needed bandwidth and for this reason its introduction will be gradual and will coexist with traditional RAN solutions in which Ethernet traffic is carried towards the radio base stations. In this paper, we propose an Xhaul optical network architecture based on Optical Transport Network (OTN) and Dense Wavelength Division Multiplexing (DWDM) technologies. The network allows for a dynamic allocation of the bandwidth resources according to the current traffic demand. The network topology is composed of OTN/DWDM rings and the objective of the paper is to evaluate the best configuration (number of rings and number of wavelengths needed) to both to minimize the cost and to provide an implementable solution. We introduce an analytical model for the evaluation of the number of wavelengths needed in each optical ring and provide some results for 5G case studies. We show how, although the single ring configuration provides the least cost solution due to the high statistical multiplexing advantage, it is not implementable because it needs switching apparatus with a too high number of ports. For this reason, more than one ring is needed and its value depends on several parameters as the offered traffic, the number of Radio Remote Units (RRU), the percentage of business sub-area and so on. Finally, the analytical model allows us to evaluate the advantages of the proposed dynamic resource allocation solution with respect to the static one in which the network is provided with a number of wavelengths determined in the scenario in which the radio station works at full load. The bandwidth saving can be in the order of 90% in a 5G traffic scenario.

The introduction of optical transport network (OTN) switching technology in metropolitan networks enables efficient wavelength bandwidth utilization and reduces the number of wavelengths, leading to reduced network costs. It has been shown that the use of integrated OTN/WDM switch architecture is cost effective because it reduces the number of short-reach client interfaces and the rack space compared to an architecture that uses a re-configurable optical add-drop multiplexer and a separate standalone OTN switch or one that uses back-to-back muxponder connections to perform manual grooming. We have proposed an integrated OTN/WDM switch that allows for significantly lower complexity and cost at the price of relaxing the nonblocking ideal performance requirements normally applied to this kind of switch. In this paper we investigate the impact that the switch blocking has on the network performance in static and dynamic scenarios. We formulate the routing problem in the integrated OTN/WDM network as an integer linear problem and develop an efficient heuristic to evaluate the blocking performance in a static traffic scenario. We study the blocking degradation of the proposed switch in the case of some metropolitan networks, and we show how higher blocking occurs in networks having a larger average node degree. We also show that the degradation of two orders of magnitude in blocking probability occurring under a dynamic traffic scenario can be mitigated with the introduction of a spatial speedup equal to 1.5