There is a need for the more efficient use of spectrum in 5G to meet more and more demand for data. Regulators and operators have to come out with more innovative methods to use the spectrum. These are some of the key areas that are being focused in order to deal with spectral efficiency challenges within the scope of 5G mobile networks.
1. Dynamic Spectrum Access
More versatile Spectrum allocation approach has to be used to optimize spectrum usage, compared to the traditional static allocation of spectrum to optimize spectrum usage.
There are three models:
a) Exclusive Use Model
Flexibility is added into the current spectrum regulatory policy in order to improve spectrum efficiency. Following are the two approaches:
- Spectrum Property Right – licensees are permitted to sell and trade their acquired spectrum and freely select a suitable technology
- Dynamic Spectrum Allocation – exploits the spatial and temporal traffic information for different applications and services.
b) Open Sharing Model or spectrum commons
This is similar to the model used for sharing spectrum in unlicensed Industrial, Scientific and Medical (ISM) radio band. Work is being carried out on centralized and distributed approaches to address this model.
c) Hierarchical Access Model
In this model, users are divided into Primary and Secondary categories. There are two approaches for sharing the spectrum:
- Spectrum Overlay approach or Opportunistic Spectrum Access ( OSA) – Secondary users use white spaces by transmitting when primary users are not using the spectrum band
- Spectrum Underlay Approach or Spectrum Wide band ( UWB) – Both primary and secondary users are allowed to use spectrum bands simultaneously. However strict constraints are imposed on the level of transmission the secondary users.
2. Regulatory Policy
Regulators have to adopt flexible‐use policies. Operators should be allowed to use any wireless technology or standard to provide a given service. This will encourage operators to develop and enhance their networks with the latest technologies. However, the impacts of sharing spectrum between different technologies need to be approached with extreme caution in order to guarantee the QoS for services. The operating conditions of the spectrum band, various performance indicators and interference mitigation techniques will have to be taken care of.
3. Market oriented spectrum spectrum management
The wireless regulatory models are undergoing changes in accordance with evolving policy priorities, driven by market and industry requirements. These shifts in approach have been triggered by advances in wireless communication technologies and socio‐economic needs.
Efforts for spectrum optimization are leading regulatory bodies to manage spectrum using both administrative and market‐oriented approaches. They are adopting new approaches in spectrum allocation and assignment through spectrum sharing, greater use of unlicensed spectrum, international and regional harmonization and incentive pricing mechanisms.
Licensed Shared Access (LSA) and Authorized Shared Access (ASA) are examples of these initiatives. The LSA and ASA concepts permit spectrum licensed for mobile communications to be used by more than one entity. Another application scenario for LSA/ASA is government and military spectrum which are sparingly used either in geographical coverage or temporal characteristics.
LSA/ASA licensees require an agreement with the incumbent user, which will be based on a sharing framework negotiated jointly between the involve parties and a regulator.