t or free as traffic travels mostly over fixed lines rather than operators' wireless links. This fits well with a recent trend called bring your own device (BYOD) has become very popular with many companies. BYOD generally means an employee uses his/her personal device (smartphone, tablet, PC) also at work. Under BYOD regimes high quality reception is a significant requirement everywhere in the office, and in many instances can only be delivered through femtocell configurations. The value proposition for the operator is high quality network coverage at lower cost, as a similar level of quality necessitates more macro/micro base stations. Operators have generally followed two main different femtocell roll-out models: one where the equip- ment remains a property of the operator; and another where it is sold to the subscriber. In the former, an operator incurs the cost of the equipment and needs to also service and maintain the device if it breaks down. In the latter, a subscriber purchases the femtocell equipment, and is responsible for its installation and repairs. This may be considered unfair as the customer is burdened with the cost of repairing an operator's coverage gap. However, owners of commercial buildings may be incentivised to install femtocell equipment and provide high quality coverage to prospective tenants. In either case, the femtocell traffic is carried over a fixed [digital subscriber line (DSL), cable] link to the operators' core networks. This traffic may count towards a subscriber data allowance and be accordingly charged. Femtocell roll-outs have been attempted by a large number of operators around the world. Some operators have in contrast decided against using these devices. At times an operator's marketing of femtocells has been considered as evidence of defects in its net- work coverage. One operator referred to a competitor's usage of femtocells as a 'means of compensating for poor coverage' [13]. Subscribers have also rightly asked why they should bear the cost of equipment which fixes 