# Evolution of Access Network Sharing and Its Role in 5G Networks
## 5 Fixed Access Network Sharing Economics
### New Ownership Models  
As 5G networks promise unprecedented support for novel heterogeneous services, new business and ownership models are required that take into consideration their entire value chain, that is, InP, network operators and over the top service providers. To achieve the target sharing level, all parties will be required to collaborate and cooperate regardless of the potential competition among them. This is not an easy goal to achieve as they often have conflicting interests, which could be a serious obstacle to their commitment. Thus, a robust mechanism to assure the commitment of all the parties is required. The study of interactions among parties with conflicting interest is not a new field, neither in economics nor in telecommunication networks. Indeed, the application of game theory to economics is solely dedicated to resolving such situations, where the strategic interaction between decision-makers are involved in a collective decision-making process. These parties might have conflicting and contradicting interests; therefore, they are more committed to achieving a better outcome for themselves than for the system as a whole. Game theory has been widely used to solve collaborative resource sharing problems in a wide range of subjects, including computer science, telecommunications, management, etc. One of the most successful examples of game theory applied to resource sharing is the wireless spectrum sharing in telecommunication networks. Initially, it was used in primary spectrum licensing, which involves one time nationwide auctioning of the scarce spectrum, usually conducted by the governments. However,such long-term fixed spectrum licences (e.g. latest ComReg's 3.6 GHz Band Spectrum award for the duration of 15 years [85]) to primary users leads to low utilization of the spectrum (more than 70% of the radio spectrum, in certain times or geographic locations [86]). The inefficient use of spectrum has prompted the regulators to investigate the secondary use of the licensed spectrum, where the primary users can improve the utilization of the spectrum allocated to them by enabling the reuse of the underutilized bands by secondary users [87]. The fixed access sharing is very similar to the spectrum licensing, as for instance, current sharing methods of dedicating entire fibre or wavelength channels lead to low utilization of the access network capacity. Thus, an opportunistic secondary sharing scheme could be adopted to assure higher utilization of the network. Considering the reusable capacity of the FANS as a tradeable commodity and a market-based sharing scheme for the under-utilized capacity sharing, the following issues need to be addressed:  
1. **Lack of trading activity**[88]: Operators' unwillingness to join and participate in the market, which could lead to limited tradeable resources, therefore, lack of sufficient liquidity in the market. _State-of-the-Art solutions:_ * Providing sufficient control over the critical network functions, such as scheduling [38], so that operators can offer QoS-oriented services to their customers (see Section 3). * Providing participation incentive through monetary compensation. In [89; 90] a marketplace is proposed to allow multiple network operators to utilize a passive optical network infrastructure and reuse others' under-utilized capacity. This marketplace provides monetary compensation to the operators who share their excess transmission opportunities. The market assumes an ownership model where an infrastructure provider owns the entire PON and allocates a certain capacity to the virtual network operators, which can trade their excess capacity among them. The network operators will benefit from this as they can monetize their idle resources and in peak usage times serve their customers with a higher Peak Information Rate (PIR). The InP also enjoys some advantages as it can utilize its resources more efficiently.