1 research outputs found
Placement and Assignment of Servers in Virtualized Radio Access Networks
The virtualization of Radio Access Networks (RANs) has been proposed as one
of the important use cases of Network Function Virtualization (NFV). In
Virtualized Radio Access Networks (VRANs), some functions from a Base Station
(BS), such as those which make up the Base Band Unit (BBU), may be implemented
in a shared infrastructure located at either a data center or distributed in
network nodes. For the latter option, one challenge is in deciding which subset
of the available network nodes can be used to host the physical BBU servers
(the placement problem), and then to which of the available physical BBUs each
Remote Radio Head (RRH) should be assigned (the assignment problem). These two
problems constitute what we refer to as the VRAN Placement and Assignment
Problem (VRAN-PAP). In this paper, we start by formally defining the VRAN-PAP
before formulating it as a Binary Integer Linear Program (BILP) whose objective
is to minimize the server and front haul link setup costs as well as the
latency between each RRH and its assigned BBU. Since the BILP could become
computationally intractable, we also propose a greedy approximation for larger
instances of the VRAN-PAP. We perform simulations to compare both algorithms in
terms of solution quality as well as computation time under varying network
sizes and setup budgets