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Cell outage management is a self-healing functionality in future mobile cellular networks, aiming to automatically detect cell or site level outages (cell outage detection) as well as to mitigate as much as possible the caused degradation of coverage, capacity and/or service quality (cell outage compensation). Cell outage compensation has a variety of control parameters (and combination thereof) at its disposal in surrounding cells/sites, including the reference signal power PRS, antenna tilt, scheduling parameters and the uplink target received power level P0. By appropriately tuning these control parameters, the outage-induced performance effects can be minimised, in terms of some operator-specified balance of relevant performance metrics. This paper analyses the effectiveness of selected control parameters in mitigating the effects of cell/site outages, learning that the antenna tilt and P0 are most effective in restoring coverage, while P0 is most effective in restoring user throughput performance. © 2011 IEEE.

The robustness of complex networks, like metro networks, is a really important issue to our daily life. With robustness we indicate the extent to which a network can deal with challenges imposed on the network, such as failures or attacks of nodes and/or links of the network. In this case the stations of the metro networks are the nodes of the complex network and the rail tracks are the links. The robustness of these networks will be related to the expected relative size of the largest connected component as a function of node failure probability of the network for the specific case of random nodes removal, which is presented in plots. The plots show that the smaller metro networks are more robust than the larger ones, at least according to our definition of robustness. The smallest network is the network of Rome with 5 nodes and the largest one is London with 83 nodes. Also the numbers of iterations which are needed to calculate the largest connected component and the impact of two networks, with same number of nodes and various numbers of links, on the expected relative size have been discussed in this report.

Driven by a combination of flat lining revenues and an explosive growth in the mobile data traffic and hence the need for network resources, mobile operators consider infrastructure-and spectrum sharing as a means to reduce operational costs. We develop and apply an assessment approach to quantify the benefits associated with spectrum sharing in an infrastructure-shared environment, and estimate the evolution of the derived 'spectrum sharing dividend' as traffic loads, radio access technologies, spectrum availability and performance targets change over time. The obtained insights can assist operators and regulators in their assessment of the merit of spectrum sharing. Analysis shows that operators with loads that peak at different times continue to benefit significantly by sharing spectrum, despite the diminishing 'trunking gains' of spectrum sharing as individual operator loads and capacities increase over time. © 2014 IFIP.

Cell outage compensation is a self-healing function and as such part of the Self-Organising Networks concept for mobile wireless networks. It aims at mitigating the degradation of coverage, capacity and service quality caused by a cell or site level outage. Upon detection of such an outage, cell outage compensation tunes a variety of control parameters, e.g., electrical antenna tilt and uplink target received power level, in cells surrounding the affected site, in order to minimise the outage-induced performance effects in accordance with the operator policy. In this paper we outline the cell outage management framework, propose concrete compensation algorithms and assess the achieved performance effects in various scenarios. The reported simulation results show that the proposed compensation algorithm is able to recover a significant percentage of the users that would otherwise be dropped, while still providing sufficient service quality in the compensating cells. © 2011 IEEE.