Page 129 - 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

etc.) that are subject to the RRM policies and the The sum of the rRMPolicyDedicatedRatio values
RRMPolicy_ IOC represents the properties of an shall be less or equal than 100.
abstract RRMPolicy that defines two attributes: the
resourceType attribute, used to define the type of • rRMPolicyMinRatio, defines the minimum
resource (e.g. PRB, RRC connected users, etc.) and resource usage quota for the associated
the rRMPolicyMemberList attribute, used to indicate network slice(s), including prioritized
resources and dedicated resources, which
the associated network slice or group of network means the resources quota that need to be
slices that is subject to this policy. The associated guaranteed for use. The sum of the
network slices are specified here in terms of slice ‘rRMPolicyMinRatio’ values shall be less or
identifiers such as the Single Network Slice
Assistance Information (S-NSSAI) and Public Land equal than 100.
Mobile Network Identifier (PLMNid). • rRMPolicyMaxRatio, defines the maximum
resource usage quota for the associated
RRMPolicyManagedEntity network slice(s), including shared resources,
<<proxy class>> prioritized resources and dedicated resources.

1 Proxy class that represents an The sum of the ‘rRMPolicyMaxRatio’ values can
<<IOC>>NRCellCU, or an be greater than 100.
<<names>> <<IOC>>NRCellDU or an 4. ML-ASSISTED CROSS-SLICE
<<IOC>>GNBCUUPFunction, or an OPTIMIZATION SOLUTION
* <<IOC>>GNBCUCPFunction, or an
<<IOC>>GNBDUFunction. This section describes an ML-assisted solution for
cross-slice optimization based on the O-RAN
RRMPolicy_ framework and network slicing information models
Abstract presented in the previous section. The solution is
<InformationObjectClass>>
conceived to be deployed as part of the RAN SMO.
<<inherits>> The functional model and components of the
resourceType solution are illustrated in Fig. 5. The cross-slice
rRMPolicyMemberList
radio resource optimization problem considered
here consists of dynamically adjusting the amount
of downlink radio resources assigned to each RAN
RRMPolicyRatio slice in each of the cells where the RAN slice is
<InformationObjectClass>>
accessible in order to account for the spatio-
temporal traffic variations across the cells. The
rRMPolicyMaxRatio solution is designed to operate with N cells and K
rRMPolicyMinRatio RAN slices and keep track of the traffic variations in
rRMPolicyDedicatedRatio periods (time steps) of t minutes. This is achieved

Fig. 4 – Simplified representation of the classes and attributes through the dynamic configuration of the
for configuration of RAN functions subject to RRM policies for rRMPolicyDedicatedRatio attribute of each cell on a
slice management. per RAN slice basis. This configuration is conducted
via the management provisioning services offered
On this basis, the RRMPolicyRatio IOC represents a
particular realization of an RRMPolicy. Specifically, by the O1 interfaces, as seen in Fig. 5. In particular,
rRMPolicyDedicatedRatio
the
since
attribute
it establishes a resource model for resource establishes the resource usage quota assigned to
distribution among slices based on three resource the RAN slice defined in terms of the fraction of
categories: shared resources (shared among slices Physical Resource Blocks (PRBs) that can be used
with no specific guarantees per slice), prioritized by this slice, the attribute is configured in the O-DU
resources (guaranteed for use by associated slices unit, so that the MAC layer can take this resource
but still usable for other slices when free), and
dedicated resources (only used for the associated usage quota into account when allocating PRBs to
slices). Accordingly, the following attributes are the users of the RAN slice in the cell.
included in the RRMPolicyRatio IOC: For determining the rRMPolicyDedicatedRatio for
the n-th cell and the k-th slice, denoted as (k,n), the
• rRMPolicyDedicatedRatio, defines the dedicated
resource usage quota for the associated
network slice(s), including dedicated resources.

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