Energy efficiency in cellular mobile radio networks has recently gained great interest in the research community. The development of more energy efficient hardware and software components aside, effect of different deployment strategies on energy efficiency are also studied in the literature. The latter mainly consist of optimizing the number and the location of different types of base stations in order to minimize the total power consumption. Usually, in the literature, the total network power consumption is restricted to the sum of the power consumption of all base stations. However, the choice of a specific deployment also affects the exact implementation of the backhaul network, and consequently its power consumption, which should therefore be taken into account when devising energy efficient deployment. In this paper, we propose a new power consumption model for a mobile radio network considering backhaul. We then handle a case study and perform a comparison of the power consumption of three different heterogeneous network deployments, and show how backhaul has a non-negligible impact on total power consumption, which differs for different deployments. An energy efficiency analysis is also carried out for different area throughput targets.

Abstract:We investigate a digital back-propagation simplification method to enable computationally-efficient digital nonlinearity compensation for a coherently-detected 112 Gb/s polarization multiplexed quadrature phase shifted keying transmission over a 1,600 km link (20x80km) with no inline compensation. Through numerical simulation, we report up to 80% reduction in required back-propagation steps to perform nonlinear compensation, in comparison to the standard back-propagation algorithm. This method takes into account the correlation between adjacent symbols at a given instant using a weighted-average approach, and optimization of the position of nonlinear compensator stage to enable practical digital backpropagation.

In the open access network model, the roles of the service provider and the network owner are separated, and the service providers get access to network and the end customers on fair and non-discriminatory conditions. This should be compared to the traditional vertically integrated business model where the service provider and the network operator are the same. A large number of open access networks have been deployed in Sweden over the last 10 years. In this paper we give an overview of such networks, draw conclusions from the Swedish experiences with open access, and outline the perspectives for future deployments both within and outside of Sweden.

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Abstract-Increasing bandwidth demand drives the need for next-generation optical access (NGOA) networks that can meet future end-user service requirements. This paper gives an overview of NGOA solutions, the enabling optical access network technologies, architecture principles, and related economics and business models. NGOA requirements (including peak and sustainable data rate, reach, cost, node consolidation, and open access) are proposed, and the different solutions are compared against such requirements in different scenarios (in terms of population density and system migration). Unsurprisingly, it is found that different solutions are best suited for different scenarios. The conclusions drawn from such findings allow us to formulate recommendations in terms of technology, strategy, and policy. The paper is based on the main results of the European FP7 OASE Integrated Project that ran between

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The frequency domain equalizers (FDEs) employing two types of overlap-add zero-padding (OLA-ZP) methods are applied to compensate the chromatic dispersion in a 112-Gbit=s non-return-to-zero polarization division multiplexed quadrature phase shift keying (NRZ-PDM-QPSK) coherent optical transmission system. Simulation results demonstrate that the OLA-ZP methods can achieve the same acceptable performance as the overlapsave method. The required minimum overlap (or zeropadding) in the FDE is derived, and the optimum fast Fourier transform length to minimize the computational complexity is also analyzed. Keywords. Frequency domain equalizers (FDEs), overlapsave (OLS), overlap-add (OLA), chromatic dispersion (CD), quadrature phase shift keying (QPSK). PACS ® (2010). 42.25.Kb, 42.79.Sz.

PolMux QPSK has emerged as the solution of choice for the first commercial implementations of 100 Gb/s transmission systems. Thanks to coherent detection and digital signal processing (DSP), linear distortions such as chromatic dispersion (CD) and polarisation mode dispersion (PMD) can in principle be completely compensated for. And indeed, effective algorithms have been devised and extensively investigate that allow CD-and PMD-resilient transmission of 100 Gb/s over long distances, leaving optical noise accumulation and non-linear impairments as the factors ultimately limiting reach. In this paper, we present the evaluation of a simple algorithm to compensate for intra-channel Kerr non-linearity (both intra-and cross-polarisation) arising in the transmission of PolMux QPSK signals at 100 Gb/s.