1 Introduction
2 Resource virtualisation and sharing
2.1 Resource sharing in wired networks
2.2 Resource sharing in wireless networks
3 Three-layered model of future communication networks
3.1 Infrastructure layer
3.1.1 Challenges
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First, a common interface with a set of SDKs is needed to control and coordinate the usage of various access technologies. The orchestrator (described in the following section) has to be able to communicate effectively with any supported access technology regardless of the manufacturer or vendor of the device. This aspects will require a common agreement (probably in form of a standard) between various stakeholders.
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Additionally, a control information overhead is needed for effective coordination of the underlying access technologies. However, its inclusions in the whole information exchange consumes additional power and bandwidth.
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One may expect increased complexity of transmitters and receivers architecture as the resource sharing is to be implemented at the level of physical medium, e.g. access to fibre or spectrum;
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On the other hand, if resource sharing is implemented at higher layer, i.e., above MAC layer, the challenge is to abstract available resources reliably, e.g. throughput in wireless network is varying depending on the channel conditions and interference plus noise floor. Also, a dedicated mapping tool will be needed which will be responsible for projecting the transmit opportunities offered by the specific transmission technique (e.g. MIMO transmission scheme, multipoint transmission like Coordinated MultiPoint—CoMP, enhanced inter-cell interference cancellation ICIC, etc.), to the form understandable by the orchestration layer (as it is proposed in, e.g. [43].
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Finally, mostly in wireless transmission, additional interference can be expected as the result of inaccurate and not-always-reliable decisions of the orchestrator.
3.1.2 Supporting technologies
3.2 Orchestration layer
3.2.1 Challenges
3.2.2 Supporting technologies
3.3 Service layer
3.3.1 Challenges
3.4 Comparison of the proposed architecture and the traditional approach
Feature | Three-layer model | Traditional model | Other comments |
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Ownership | It is possible that each layer will be a subject of interest of a separate company: one for infrastructure delivery, one for service offers and another for spectrum management and network orchestration | In this scheme, it is the (mobile) network operator who manages and invests in each layer of the three layer model | Mixture of these two models are possible; there could be a company that manages both hardware and spectrum resources but does not offer services to single clients |
The split of ownership is horizontal | The vertical split among three layers is applied in traditional approach | ||
Investments | In the three-layer model lower investments can be envisaged, as these are limited to a single layer | Huge investments are required to grant spectrum access, to deploy network architecture and offer services to the end-users | |
Business model | In this approach the business model is highly flexible; separate investment policies may be applied for each layer, since each layer exhibits a different profit margins and different return periods | Classic solutions for service delivery based on the owed underlying infrastructure are applied | It is worth mentioning that three-layer model enables natural form of collaboration of different vertical markets on a single layer. So, for example towers used for transport of energy may be also used for transport of information by telecom operators |
Costs | Depending on the layer, the CAPEX/OPEX figures are different. However, as for the infrastructure layer both costs are high, while for service layer these values will are relatively low, but profit margins are also low. So as a consequence, service provides need to operate at much wider scale | In the classic approach, both costs are relatively high since they include blended costs of the related three layers | In both models high costs of infrastructure investments create bottleneck for fast development, as the rate of return and the typical time for acceptable return of investment are rather challenging |
Technology-focused or technology-agnostic | In a virtualized world described by the three layer model, the underlying infrastructure (thus transmission technology) is transparent to the service providers. The service provider is not aware of transmission standard used for guaranteeing its service delivery. The underlying transmission technology may be upgraded with new features or may even be replaced | Network operators have to plan their investment carefully; as their selection of the transmission technology will either prevail or impair their position on the market | Operators of a single layer in the three-layer model may in theory operate in more efficient way since given layer may be offered to various vertical markets. Thus, the technology of a single layer may combine requirements of various vertical markets |
3.5 Exemplary use case
4 Market and regulatory constraints
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Indoor WLAN—to facilitate the extension of currently allocated frequency bands in 5 GHz range and sharing of additional bands with existing services;
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Small cell outdoor—to prevent the deployment of many competing small cell networks which could cause significant interference;
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Internet of Things—to provide the spectrum in situations where infrequently a small amount of data needs to be send over a short distance.