6 1 Networking Cyber-Physical Systems: System Fundamentals of Security and. ..
From existing literatures, the introduction of cloud computing architectures in
next-generation wireless networks is mainly concentrated in three areas: Cloud
RAN, Network Functions Virtualization and Software Define Networking [12].
1. Cloud RAN
Since the 3G era, distributed base station architecture (BBU) has been widely
used in Radio Access Networks (RAN) of wireless network architecture. In the
vision of the next-generation wireless network, the deployment of wireless networks
will exceed the existing sites by more than 10 times in the future, and the ratio
of active users to the number of sites will reach 1:1. At the same time, a friendly
user experience should be guaranteed. According to the existing base station
deployment method, the next-generation wireless network construction requires
the input of massive network equipment, it will inevitably result in a decrease in
device utilization. Therefore, in order to provide resilient and scalable base station
services, the cloud computing architecture is adopted in the RAN part of wireless
networks, and distributed base stations are centralized management, forming a BBU
pool through virtualization. Sending or receiving of signals from the wireless access
unit (RAU) will be backed up by virtual base stations specified in real time in the
BBU pool.
The Cloud RAN can not only flexibly configure the base station resources,
but more importantly, the CoMP (Coordinated Multiple Points Transmis-
sion/Reception) technology can be implemented based on the Cloud RAN
architecture. Next-generation wireless networks belong to ultra-dense heteroge-
neous networks. Densely deployed networks narrow the distance between terminals
and nodes, which greatly improves the power and spectrum efficiency of the
network. However, the interference between wireless nodes has become particularly
serious. CoMP technology can implement multiple peer BBUs located in different
geographical locations, cooperating to participate in data transmission or reception
for one terminal, thereby avoiding interference between different RAUs, so that it
can improve the utilization of wireless spectrum. Therefore, the virtualized BBU
pool can provide strong support for CoMP technology through unified configuration
and management of virtual BBUs.
2. NFV [13]
In the wireless network, there are a large number of net elements that perform
network optimization and management functions, such as load balancing, firewall,
DNS and other devices. Most of them are dedicated network devices. Based on
the virtualization technology of the cloud computing architecture, the European
Telecommunications Standards Institute (ETSI) proposed a NFV (Network Func-
tions Virtualization) architecture in 2012 [14]. The main idea of NFV architecture
consists of two aspects, one of which is to abandon specialized network element
equipment and adopt common IT equipment. For instance, computing resource pool
can be built with common servers; the other is to use VNF manager to discharge
various types of virtual network elements with virtualized computing resource pool.