Coordination protocol for inter-operator spectrum sharing in co-primary 5G small cell networks

Abstract

We consider spectrum sharing between a limited set of operators having similar rights for accessing spectrum. A coordination protocol acting on the level of the Radio Access Network (RAN) is designed. The protocol is noncooperative, but assumes an agreement to a set of negotiation rules. The signaling overhead is low, and knowledge of competitor's channel state information is not assumed. No monetary transactions are involved; instead, spectrum sharing is based on a RAN-internal virtual currency. The protocol is applicable in a scenario of mutual renting and when the operators form a spectrum pool. The protocol is reactive to variations in interference and load of the operators, and shows gains in a simulated small cell scenario compared to not using any coordination protocol.

Licensed Spectrum Sharing Schemes for Mobile Operators: A Survey and Outlook

“…In the case that national roaming is not a desirable solution for the competitive MNOs, other types of sharing such as mutual renting and LSA-like approaches can prove beneficial. In this case, the MNOs can leverage their own existing infrastructure Mutual Renting (V-C-2-a) [115], [126][127] Spectrum Pooling (V-C-2-b) [80], [82], [84][85], [97] Inter-operator Spectrum and RAN Sharing (V-C-1)…”

“…This is achieved by flexibly modifying the phase and amplitude of the signals to shape and steer the direction of the radiated beam vertically and horizontally to create constructive or destructive interference. Constructive interference is used to amplify the beam in a given direction, while destructive interference is used to focus the beam, enabling it to be steered precisely [85]. In the context of spectrum sharing, beamforming techniques facilitate co-existing multitechnology deployments.…”

“…Database driven (e.g., geo-location database) [37], [79] + Provides accurate information regarding spectrum availability across the network + Reliable interference protection for sharing players + Can be an unbiased entity for fair spectrum allocation among sharing players -T oo complex for real-time spectrum opportunity detection -Requires additional infrastructure for deployment such as backhaul -Requires a third party to manage the sharing procedure -Imposes excess signalling overhead to the network/participating systems -Vulnerable to jamming attacks Spectrum broker/ Super resource scheduler [83], [84] Distributed Spectrum sensing (e.g., energy detection) [61], [37] , [33], + Is capable for on-demand and real-time spectrum opportunity detection + No additional infrastructure is required + Only target UE is involved to perform sensing, thus, lower signalling is imposed to the network -Is vulnerable to some issues such hidden node, false alarm and detection -Is not reliable for QoS sensitive services when sensing is performed by UE Coordinated Beamforming [85], [86] + Simultaneous utilisation of spectrum by multiple service providers + Increased spectrum utilisation efficiency -Requires CSI sharing between sharing players -Requires interface (such as backhaul, X2, etc.) between sharing players Game-T heory based coordination [87], [88], [89] + Low to no, information sharing between sharing players during sharing procedure + Low to no overhead is imposed to the network -Implementation complexities -Low fairness guarantees between sharing players…”

“…Firstly, the concept was proposed by QUALCOMM [139], and developed further by CEPT, taking into account more comprehensive regulatory aspects (i.e., the level of authorisation), in order to form a more robust sharing regime, known as LSA. In LSA framework, a non-mobile wireless service provider, which could be a governmental/commercial [15], [85], [133] => Game-theory based approach => Cooperative games performs based on presharing agreements among MNOs + No need for real-time inter-MNO information sharing -Efficient and fair policies are complex to implement [87], [88], [97] incumbent, agrees to share part of its exclusive band with one or multiple MNOs, referred to as LSA licensees [48]. The framework was introduced with the aim of offering promising opportunities for the capacity and bandwidth expansion in cellular systems [137].…”

Enhanced Co-Primary Spectrum Sharing Method for Multi-Operator Networks

“…The proposed solution is easy to control and incurs low signaling overhead. In [13], a CoPSS scenario where operators having similar rights for accessing spectrum is evaluated. A coordination protocol is designed which assumes an agreement to a set of negotiation rules.…”