Page 168 - ITU Journal, Future and evolving technologies - Volume 1 (2020), Issue 1, Inaugural issue

ITU Journal on Future and Evolving Technologies, Volume 1 (2020), Issue 1

of self-interested MNOs decide to pool together their re- acts as the employer whereas the InPs as employees.
spective network infrastructures and create a Joint Ven-
ture (JV), responsible for managing their shared net- Instead, Wei et al. in [147] take a centralized approach.
work. In turn, MNOs will leaseback network capacity Specifically, the work in [147] considers multiple InPs
from the JV. The authors propose a Stackelberg game and multiple VNOs (analogous to SPs) in the context
to determine the shares MNOs obtain from the JV and of WNV. Here, each InP has a given set of users of its
the prices set by the JV to the MNOs and by the MNOs own; resources allocated to its own users are referred to
to their respective users. as local slices and the total rate across the local slices
should be above a given minimum for each InP. Instead,
Notably, the user perspective is considered in [94], which resources allocated to users of an MVNO are referred to
investigates the problem of user-to-BS association when as foreign slices. Each InP is characterized by a given
multiple MNOs decide to pool together their respective bandwidth (number of subchannels) and power budget
network infrastructures. The authors propose a non- for the downlink of a BS. The problem consists in deter-
cooperative game to model the problem of each user mining the number of subchannels and amount of power
selecting its serving BS from the shared pool, indepen- to allocate to each slice by each InP. The objective is to
dently, so that its individual data rate is maximized. maximize the total rate across all slices while satisfying
the bandwidth and power constraints and the minimum
rate requirement for the local slices of each InP. Conse-
The work in [126] represents a fresh take on infrastruc- quently, the problem is formulated by means of an Inte-
ture sharing. Its authors consider a set of MNOs with ger Programming (IP) model. In this model an MVNO
individual but overlapping infrastructures (BSs) and in- can be simultaneously served by multiple InPs, likewise
dividual spectrum licenses; in this setting one of the an InP can simultaneously serve multiple MVNOs.
MNOs (the buyer) can purchase the use of BSs of the
other MNOs (the sellers) for serving its own users at The authors in [156] propose a hierarchical (two layer)
its own licensed spectrum. The buyer MNO evaluates combinatorial auction to model the interactions among
whether it can provide a given (Quality of Service) QoS multiple InPs, multiple MVNOs (analogous to SPs), and
to its own users through its own infrastructure by in- multiple end users concerning the resource allocation
creasing the transmission power of its BSs or by pur- at the BS level (the resources here being transmission
chasing BSs from the seller MNOs. In the latter case, power, number of channels and number of antennas).
the buyer MNO has to decide from which seller MNOs
to buy from and what fraction of their BSs to purchase In [28] we propose a novel framework based on a Multi-
so as to minimize its expenditures while satisfying the Leader-Follower Game (MLFG) to study the techno-
QoS of its users. In turn, the seller MNOs have to decide economic interactions among multiple InPs and multiple
the fraction of their own BSs to sell so as to maximize SPs in a 5G context.
their profit (payment from the buyer MNO minus cost Table 3 summarizes the main issues that are considered
of sold BSs) where the competition in quantity among in this subcategory: what are the actors that intervene
the seller MNOs is modeled as a Cournot market. in the infrastructure sharing scheme and what is the
modelling and mathematical approach that is taken in
3.5.2 Infrastructure sharing for decoupled in- each case.
frastructure from services
Article Actors Approach
We remind the reader that we have discussed the vary- [30] many InPs - one SP contract theory
ing terminology used across different articles related to [147] many InPs - many SPs IP model
the infrastructure sharing for decoupled infrastructure [156] many InPs - many SPs auction theory
from services in Section 3.2 and that we have maintained [28] many InPs - many SPs MLFG
the authors’ terminology for the considered stakehold-
ers when describing their articles and, when necessary, Table 3 – Infrastructure sharing for decoupled infrastructure from
we provide clarifications on how they compare to our services
definitions of InPs and SPs.
It is worth pointing out that, across the different articles 3.6 Miscellaneous
very distinct mathematical approaches have been used
to study the interaction among InPs and SPs. 3.6.1 Infrastructure sharing for mobile net-
work segments other than the access
Rather exceptionally, the study in [30] tackles the in-
teraction among InPs and MVNOs (analogous to SPs) Infrastructure sharing and multi-tenancy can also be ap-
from the MVNO perspective. In fact, the authors in [30] plied to specific segments of a mobile network other than
consider multiple InPs but a single MVNO and propose the access. For instance, the studies in [23,98,128,140,
a model based on contract theory in which the MVNO 141] address sharing of the backhaul network whereas

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