TIA TIA-4973.211

Scope (Informative)

Priority and QoS refers to the access and control of systemresources; especially with respect to a wireless broadband network.While the lion’s share of attention is paid in this specificationto wireless broadband network resources, this specification is notlimited thereto. Transport network, backhaul, and interconnectedsystems are all considered.

The public safety broadband network is a challengingenvironment. Various types of users (e.g., first responders, secondresponders, etc.) with various disciplines (police, fire, EMS ,etc.) and all types of applications (voice, video, data) all sharethe same resources. This creates an unprecedented environment forthe management of resources for a public safety system.Conventional LMR systems have dedicated resources for Push-to-Talk,and there is traditionally only limited sharing of a system betweendisciplines. Trunked LMR systems improve sharing betweendisciplines, but still don’t have to share resources like LTEall-IP users.

Priority, as used herein, refers to the ability for a given userto access and obtain resources from the broadband network. Once auser has been granted resources by the system, quality of service(QoS) refers to the specific attributes (e.g., latency, packet lossrate) that govern the experience of content exchange with the user.Users of the public safety broadband network need a consistent anddeterministic service for real-time management of priority andQoS.

Commercial cellular network operators typically offer elevatedpriority to premium customers on a statically assigned basis (i.e.,the customer’s priority only changes with changes in theirsubscription level). While this is sufficient for commercial use,public safety users require priority services that aresituational. The sheriff at a traffic stop does notrequire the same priority on the broadband network as a patrolmanexchanging gunfire at a bank robbery. Preemption of lower-priorityresources is essential in order to provide resources to the highestpriority incidents.

Mission critical communications require immediate access toresources. Many factors can impact the resources available to agiven traffic flow: number of users, number of incidents, distanceto cell antenna, interference, etc. Further, many factors cancontribute to wireless congestion at a cell. For this reason,Priority and QoS capabilities for public safety need to considerthe dynamic situational aspects of responders. It is insufficientto statically assign a priority to a given responder that will besufficient for all situations.

Another important aspect of priority and QoS is that it is basedon the user and not a given device. In the commercial cellularworld, users obtain a personal device and that device and itstelephone number are assumed to be associated with a user. In thepublic safety world, devices are re-used across shifts (e.g.,tablets, radios, fire trucks, etc.). It is not realistic to assumethat all public safety broadband devices are personally issued. Forexample, an incident commander can pick up a shared laptopbelonging to her agency and sign-in, or can be assigned to avehicle having a fixed-mount laptop in the vehicle. Therefore,public safety priority and QoS needs to be derived for a user alsotaking into account the application(s) that he/she is currentlyinvoking, and applied to the devices currently being used by theuser. The type of user is one of many factors affecting aSubscriber’s overall priority and QoS state. See sections 3.1.3 and3.1.4 for more information.

Responders are trained today with procedures that have takendecades to perfect. Any service provided to responders has tocomplement their existing workflow. This service attempts to avoiddistracting a user from the mission by requiring him/her to enter abroadband maintenance terminal or to become aware of the broadbandnetwork’s detailed prioritization parameters. In thisspecification, prioritization is integrated into usage patternsfamiliar to the user (e.g., the emergency button).

Applications can be deployed by various domains utilizing thenetwork. For example, telephony might be deployed nationally andpush-to-talk might be deployed regionally by a state (e.g., in aseparate APN). The priority and QoS capabilities described hereinare intended to consistently govern resources for all applications,regardless of the entity (national, regional, local) that isoperating the application. This specification defines a Priorityand QoS Control Service (PQCS) to address these complex and variedneeds. The PQCS:

• Allows Subscribers, other users, and other services to controland coordinate dynamic priority changes;

• Translates a coherent model of PS state (responder emergency,etc.) to service effecting controls in a Subscriber’s transportnetwork;

• Is consistent with the principles expressed by the NPSTC LocalControl Task Group [4] the Priority and QoS Task Group [3] and theBroadband Data Protocol Standards Overview [5]; and,

• Supports “all IP” broadband networks (e.g., LTE). The PQCSdoes not support circuit-switched networks.

Scope (Normative)

This document pertains to the control of Priority and Quality ofService (QoS) for communications on a wireless broadband networkusing Internet Protocols (IP). This document describes requirementsfor a mission critical Priority and QoS Control Service for awireless broadband network. The network and its resources areassumed to be shared by different classes of users, and differenttypes of applications. Prioritization is the ability to determinewhich resource requests should be granted and which grantedresources should be discontinued or preempted. This documentincludes requirements to determine a user’s default priority on thebroadband network, and also provides requirements for dynamicprioritization changes to meet situational needs. Quality ofService is the ability to ensure that IP packet flows associatedwith different applications satisfy performance objectives neededfor the applications to operate. The requirements contained hereinallow an operator to define consistent and deterministic policiesto moderate usage of the shared wireless broadband network.Requirements are further provided for end-users and applications todynamically influence policy selection.

Edition:

14

Published:

08/01/2014

Number of Pages:

48

File Size:

1 file , 950 KB