6.7 Priority, QoS, and policy control

22.2613GPPRelease 18Service requirements for the 5G systemTS

6.7.1 Description

The 5G network will support many commercial services (e.g. medical) and regional or national regulatory services (e.g. MPS, Emergency, Public Safety) with requirements for priority treatment. Some of these services share common QoS characteristics such as latency and packet loss rate but can have different priority requirements. For example, UAV control and air traffic control can have stringent latency and reliability requirements but not necessarily the same priority requirements. In addition, voice-based services for MPS and Emergency share common QoS characteristics as applicable for normal public voice communications yet can have different priority requirements. The 5G network will need to support mechanisms that enable the decoupling of the priority of a particular communication from the associated QoS characteristics such as latency and reliability to allow flexibility to support different priority services (that need to be configurable to meet operator needs, consistent with operator policies and corresponding national and regional regulatory policies).

The network needs to support flexible means to make priority decisions based on the state of the network (e.g. during disaster events and network congestion) recognizing that the priority needs can change during a crisis. The priority of any service can be different for a user of that service based on operational needs and regional or national regulations. Therefore, the 5G system should allow a flexible means to prioritise and enforce prioritisation among the services (e.g. MPS, Emergency, medical, Public Safety) and among the users of these services. The traffic prioritisation can be enforced by adjusting resource utilization or pre-empting lower priority traffic.

The network must offer means to provide the required QoS (e.g. reliability, latency, and bandwidth) for a service and the ability to prioritize resources when necessary to meet the service requirements. Existing QoS and policy frameworks handle latency and improve reliability by traffic engineering. In order to support 5G service requirements, it is necessary for the 5G network to offer QoS and policy control for reliable communication with latency required for a service and enable the resource adaptations as necessary.

The network needs to allow multiple services to coexist, including multiple priority services (e.g. Emergency, MPS and MCS) and must provide means to prevent a single service from consuming or monopolizing all available network resources, or impacting the QoS (e.g. availability) of other services competing for resources on the same network under specific network conditions. For example, it is necessary to prevent certain services (e.g. citizen-to-authority Emergency) sessions from monopolizing all available resources during events such as disaster, emergency, and DDoS attacks from impacting the availability of other priority services such as MPS and MCS.

Also, as 5G network is expected to operate in a heterogeneous environment with multiple access technologies, multiple types of UE, etc., it should support a harmonised QoS and policy framework that applies to multiple accesses.

Further, for QoS control in EPS only covers RAN and core network, but for 5G network E2E QoS (e.g. RAN, backhaul, core network, network to network interconnect) is needed to achieve the 5G user experience (e.g. ultra-low latency, ultra-high bandwidth).

6.7.2 Requirements

The 5G system shall allow flexible mechanisms to establish and enforce priority policies among the different services (e.g. MPS, Emergency, medical, Public Safety) and users.

NOTE 1: Priority between different services is subject to regional or national regulatory and operator policies.

The 5G system shall be able to provide the required QoS (e.g. reliability, end-to-end latency, and bandwidth) for a service and support prioritization of resources when necessary for that service.

The 5G system shall enable the network operator to define and statically configure a maximum resource assignment for a specific service that can be adjusted based on the network state (e.g. during congestion, disaster, emergency and DDoS events) subject to regional or national regulatory and operator policies.

The 5G system shall allow decoupling of the priority of a particular communication from the associated QoS characteristics such as end-to-end latency and reliability.

The 5G system shall be able to support a harmonised QoS and policy framework applicable to multiple accesses.

The 5G system shall be able to support E2E (e.g. UE to UE) QoS for a service.

NOTE 2: E2E QoS needs to consider QoS in the access networks, backhaul, core network, and network to network interconnect.

The 5G system shall be able to support QoS for applications in a Service Hosting Environment.

A 5G system with multiple access technologies shall be able to select the combination of access technologies to serve an UE on the basis of the targeted priority, pre-emption, QoS parameters and access technology availability.

The 5G system shall support a mechanism to determine suitable QoS parameters for traffic over a satellite backhaul, based e.g. on the latency and bandwidth of the specific backhaul .

NOTE 3: The case where a backhaul connection has dynamically changed latency and/or bandwidth needs to be considered.