Page 144 - ITU Journal Future and evolving technologies – Volume 2 (2021), Issue 2

ITU Journal on Future and Evolving Technologies, Volume 2 (2021), Issue 2

2. LITERATURE REVIEW focus on providing quality services to users. For backhaul
sharing, several scenarios can be considered: The back‑
Infrastructure sharing in telecommunications refers to haul can be deployed by a joint venture of the participat‑
using the infrastructure or resource by more than one op‑ ing mobile operators or a private entity would deploy and
erator through an arrangement [9, 10]. It is a process operate the infrastructure and offer it to the operators in
that offers many options. Sharing decisions range from a ”platform as a service” model [15].
sites, towers to another network infrastructure such as Corenetworksharing: Here, eventheHomeLocationReg‑
RAN and spectrum. According to the literature, there is ister (HLR), the billing platform and the value‑added sys‑
no standard for infrastructure sharing, but it is consid‑ tem can be shared.
ered a practical and promising solution for reducing de‑ Active sharing in general and core network sharing is very
ployment costs [4]. The main advantages of infrastruc‑ complicated to achieve, especially when the infrastruc‑
ture sharing are the cost bene its [11, 12]. But it is also ture parties are competitors. Despite these bene its, in‑
driven by the migration to new technologies and the de‑ frastructure sharing can be a source of imbalance and
ployment of mobile broadband [13]. Infrastructure shar‑ market distortion and, if imposed from outside, can re‑
ing models are divided into two broad categories: active duce incentives to build new infrastructure and adopt
and passive sharing. new technologies[10].
Several countries worldwide have approved passive in‑
2.1 The different infrastructure sharing tech‑ frastructure sharing between operators, but some net‑
niques work operators show resistance to opt for sharing so far.
In [4], a survey on infrastructure sharing by operators
Infrastructure sharing models are divided into two broad was conducted. The results showed that infrastructure
categories: active and passive sharing. sharing among operators is de icient; mainly, site sharing
Passive sharing: This is a simple sharing model that does is the most adopted. However, a techno‑economic analy‑
not present technical dif iculties. sis of infrastructure sharing presented by [7] determined
Site sharing: This is the sharing of the geographical loca‑ that it is not theoretically green and viable for a mobile
tion of stations. In this case, all network components at network operator to own a tower alone in the case of de‑
the site belong to the operators, respectively. This mode ploying new technologies such as 5G; it could take more
essentially saves the cost of leasing or purchasing and the than 10 years to get a return on investment.
cost of operating the territory. But the dif iculty in this In rural areas, the cost of operating and maintaining ru‑
model is to ind a ixed location that suits everyone to de‑ ral sites grows exponentially with the remoteness of the
ploy the site when it is a new site. sites and the lack of adequate infrastructure to access the
Tower sharing: In this form of sharing, the site is shared sites [7]. But when network providers sell their towers,
by several operators, and the towers are also shared. Each the cost‑bene it ratio becomes more attractive [7, 10]. In
operator deploys its own equipment and has control over Madagascar, a country where two‑thirds of the popula‑
it. The passive sharing agreement can be concluded be‑ tion live in ruralareas, the adoption of passive sharing and
tween two or more operators and include third‑party backhaul by all mobile operators according to open access
companies [14] which are neutral hosts. A neutral host principles has enabled rapid, ef icient and cost‑effective
refers to a telecommunication service provider interested mobile network expansion in rural areas [10]. Despite the
in creating additional revenuesand sharing sitesor masts. technical and political dif iculties of implementing active
In these cases, costs can be signi icantly reduced when sharing, while passive sharing leads to signi icant savings,
several network operators or service providers share active sharing to some extent can signi icantly increase
physical assets and transport networks. these savings especially when appropriate technology is
Sharing can be managed by the site owner, who acts as used for sharing.
a landowner for the operators who lease the site. The
owner may be an operator sharing the site or another 2.2 Cloud‑RAN and network slicing as an ac‑
structure that provides the infrastructure. tive sharing option for bridging the digital
Active sharing: Here, sharing extends to the electronic divide
components of the network and the radio spectrum. A
distinction is made between: The concept of cloud‑RAN refers to a radio access net‑
RAN sharing: The shared equipment includes BTS, work in which BaseBand Units (BBUs) are centralized at
NodeB, BSC, RNC… and may extend to feeder cables and a geographical location such as a data center using cloud
antennas. But the transmission network and the core net‑ computing and virtualization techniques. Remote Radio
work are independent. Thus, this sharing mode allows Head (RRH) is deployed with antennas at the sites and is
operators to control their cells in their core network and connected to the BBU pool via a fronthaul link. The BBU
have a separate operation [14]. pool provides all baseband signal processing (transmis‑
Backhaul sharing: In addition to the RAN infrastructure, sion, centralized resource allocation, joint user schedul‑
operators may decide to share the transmission channel. ing, low control data, etc.) in the cloud‑RAN. In con‑
This is useful to extend their coverage more quickly and to trast, conventional base stations, which are replaced by

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