Fueled by its recent success in provisioning on-site wireless Internet access, Wi-Fi is currently perceived as the best positioned technology for pervasive mobile macro network offloading. However, the broad transitions of multiple collocated operators towards this new paradigm may result in fierce competition for the common unlicensed spectrum at hand. In this light, our paper game-theoretically dissects market convergence scenarios by assessing the competition between providers in terms of network performance, capacity constraints, cost reductions, and revenue prospects. We will closely compare the prospects and strategic positioning of fixed line operators offering Wi-Fi services with respect to competing mobile network operators utilizing unlicensed spectrum. Our results highlight important dependencies upon inter-operator collaboration models, and more importantly, upon the ratio between backhaul and Wi-Fi access bit-rates. Furthermore, our investigation of medium-to long-term convergence scenarios indicates that a rethinking of control measures targeting the large-scale monetization of unlicensed spectrum may be required, as otherwise the used free bands may become subject to tragedy-of-commons type of problems.
Differentiated by the following list of driving actors, @cite_1 have compiled a set of Wi-Fi Femto offload Value Network Configurations (VNCs): mobile operators, broadband access operators (fixed line), combined fixed and mobile operators, the access aggregator role (e.g., FON http: www.fon.com , last accessed: June 14, 2013 ), service providers and device manufacturers, as well as site venue owners. Investigating market convergence effects, the present paper will concentrate on the fixed mobile operator and access aggregator cases. These VNCs have been elaborated by @cite_3 in order to illustrate two-sided market issues towards a successful market evolution, e.g., w.r.t. required platform subsidies. Cost aspects for offloading base station traffic to femto cells have specifically been targeted by @cite_4 . However, to the best of our knowledge, the conflict of business interests and market challenges involved in offloading traffic from mobile networks to unlicensed spectrum Wi-Fi solutions has not yet been targeted in literature.
@cite_4 @cite_1 @cite_3
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Mobile data offloading through complementary network technologies such as WiFi and femtocell can significantly alleviate network congestion and enhance users' QoS. In this paper we consider a market where mobile network operators (MNOs) lease third-party deployed WiFi or femtocell access points (APs) to dynamically offload the traffic of their mobile users. We assume that each MNO can employ multiple APs and each AP can concurrently serve traffic from multiple MNOs. We design an iterative double auction mechanism that ensures the efficient operation of the market, where MNOs maximize their offloading benefits and APs minimize their offloading costs. Such a mechanism incorporates the special characteristics of the wireless network, such as the coupling of MNOs' offloading decisions and APs' capacity constraints. The proposed market scheme does not require full information about the MNOs and APs, incurs minimum communication overhead, and creates non-negative revenue for the market broker. Mobile networks are increasingly becoming capacity limited such that more base stations and smaller cells or more spectrum are required to serve the subscribers' increasing data usage. Among several challenges, the establishment of new base station sites becomes challenging and expensive. This study proposes and analyzes critical aspects of a business case where a mobile operator offloads its mobile LTE network by deploying cognitive femtocells. When aided by a sensor network the cognitive femtocell will be able to use frequencies other than the mobile network and hence increase its power to cover outdoor areas and neighbour buildings. This cognitive femtocell strategy will be compared with an alternative strategy where an operator deploys conventional femtocells and has to build additional base stations to meet the traffic demands. The business case analysis illustrates that there is a potential for cost savings when offloading the mobile network with cognitive femtocells when compared to the alternative strategy. It must be emphasized that the studied concept is innovative and that the business case period starts in 2017, hence, parameter assumptions are uncertain. Therefore, as the most important message of this work, sensitivity analysis is used to reveal the most critical aspects of the cognitive femtocell business case. It is found that the most critical parameters regarding the cognitive femtocell are the price for backhauling, the number of users supported and the coverage. Furthermore, an optimal coverage radius for the cognitive femtocell for lowest possible costs is found. Costs related to the fixed sensor network are found to be less critical since sensors are embedded in the cognitive femtocells. Sensitivity analysis is also presented for spectral efficiency, cognitive and conventional femtocell offloading gain, sensor density and price, customer density and price for base station site establishment. The main objective of the paper is to investigate and compare the downlink performance of different LTE heterogeneous network (HetNet) deployment solutions. By adding small cells to the existing macro overlay, network coverage and capacity can be significantly enhanced to accommodate the fast growth of mobile broadband traffic. Emphasis is put on how to optimally assign the spectrum for the different networks layers in an evolved HetNet including outdoor and indoor small cells. The study is conducted for a "Hot-Zone" scenario, i.e. a high-traffic area within a realistic dense urban deployment. A broadband traffic volume growth by a factor of 50 compared to today's levels is assumed. The investigated deployment schemes are outdoor pico-only, indoor femto-only and joint pico-femto deployments, all combined with an overlay macro layer. The results indicate that the best network coverage performance with a minimum user data rate of 1 Mbps is achieved when deploying small cells on dedicated channels rather than co-channel deployment. Furthermore, the joint pico and femto deployment turns out to be the right trade-off between increased base station density and enhanced network capacity. Two-tier femtocell networks- comprising a conventional cellular network plus embedded femtocell hotspots- offer an economically viable solution to achieving high cellular user capacity and improved coverage. With universal frequency reuse and DS-CDMA transmission however, the ensuing cross-tier interference causes unacceptable outage probability. This paper develops an uplink capacity analysis and interference avoidance strategy in such a two-tier CDMA network. We evaluate a network-wide area spectral efficiency metric called the operating contour (OC) defined as the feasible combinations of the average number of active macrocell users and femtocell base stations (BS) per cell-site that satisfy a target outage constraint. The capacity analysis provides an accurate characterization of the uplink outage probability, accounting for power control, path loss and shadowing effects. Considering worst case interference at a corner femtocell, results reveal that interference avoidance through a time-hopped CDMA physical layer and sectorized antennas allows about a 7x higher femtocell density, relative to a split spectrum two-tier network with omnidirectional femtocell antennas. A femtocell exclusion region and a tier selection based handoff policy offers modest improvements in the OCs. These results provide guidelines for the design of robust shared spectrum two-tier networks.