If a user invokes and is authorized for Priority Service and a radio (voice or traffic) channel is available, then the call is allowed to proceed in the originating system. The call is given priority treatment during progression through the network. If a user invokes and is authorized for Priority Service but a radio (voice or traffic) channel is not available, the call is queued for the next available radio channel in the cell in accordance with the user's priority level and call initiation time. The user should be given an indication that the call is progressing. The network treats the user as busy while a priority call request for the user is queued. If a user invokes and is authorized for Priority Service and a radio (voice or traffic) channel is not available, if the queue for the cell is full, and if the user's Priority Service priority is higher than one or more Priority Service calls already in the queue, then the lowest, most recent call in the queue is dropped from the queue. The user's call is placed in the queue in accordance with the user's priority level and call initiation time. The user should be given an indication that the call is progressing. The network treats the user as busy while a priority call request for the user is queued. It is desirable that if the system changes the resources allocated to a Service User (e.g., cell handover), the call set-up should proceed, as if the resources had remained the same (e.g., queue status). Note: The handling of queue status during handover is for further study. The following indications should be provided to the subscriber:

1. Acceptance of a Priority Service request.
2. Rejection of a Priority Service request.
3. Loss of a pending request (including loss of radio contact and possibly roaming to another system).

A priority call request may be removed from the queue by the Service User pressing the END key. The request shall also be removed by the system, if radio contact is not maintained with the requesting UE.

The Priority Service call receives priority treatment for call routing to interconnected networks supporting priority.

If a terminating radio (voice or traffic) channel is available, the call is terminated to the called party. If a terminating radio (voice or traffic) channel is not available, the call is queued for the next available radio channel in the cell serving the called party in accordance with the call's priority level. When a terminating radio channel becomes available and is assigned to the call, the call is terminated to the called party. If a terminating radio (voice or traffic) channel is not available, the queue for the cell serving the called party is full, and the call's priority level is higher than one or more Priority Service calls in the queue, then the lowest, most recent call in the queue is dropped from the queue. The user's call is entered in the queue in accordance with the call's priority level. When a terminating radio channel becomes available and is assigned to the call, the call is terminated to the called party. It is desirable that if the system changes the resources allocated to the called party (e.g., cell handover), the call set-up should proceed, as if the resources had remained the same (e.g., queue status).

At call origination, the following exceptions or unsuccessful outcomes can occur:

1. If the user invokes but is not subscribed to Priority Service, call setup is not allowed to proceed and the call is dropped.
2. If the user invokes and is subscribed to Priority Service but the user's mobile set times out while the call is undergoing Priority Service call queue processing, the user's mobile returns to the null state and the call is dropped.
3. If a user invokes and is subscribed to Priority Service, a radio channel is not available, and the queue for the cell is full, and the user's Priority Service priority is lower than all of the Priority Service calls in the queue, the call is dropped.
4. If a user invokes and is subscribed to Priority Service, and is queued for a radio channel, but the user loses coverage, the call is removed from the queue and is dropped.
5. If a user invokes and is subscribed to Priority Service, and is queued for a radio channel, but the maximum allowed call time in queue expires before a radio channel becomes available in the cell, the call is removed from the queue and is dropped.
6. If a user invokes and is subscribed to Priority Service, and is queued for a trunk resource, but the user loses coverage, the call is removed from the trunk queue and is dropped.
7. If a user invokes and is subscribed to Priority Service, and is queued for a trunk resource, but the maximum allowed call time in queue expires before a trunk resource becomes available in the cell, the call is removed from the trunk queue and is dropped.

At call termination the following exceptions or unsuccessful outcomes can occur:

1. If a radio channel is not available and the queue for the cell is full, but the calling party's priority is lower than all of the Priority Service calls in the queue, the call is not completed and the Service User is given an appropriate indication.
2. If the call is queued for a radio channel but the called party's mobile loses coverage, the call is removed from the queue and the Service User is given an appropriate indication.
3. If the call is queued for a radio channel but the maximum allowed call time in queue expires before a radio channel becomes available in the designated terminating cell, the call is removed from the queue and the Service User is given an appropriate indication.

Call Waiting Priority Service call users will not receive an incoming call indication while the call is being queued. Call forwarding and call re-direction Service users will not be allowed to invoke Priority Service calls through call forwarding or re-direction. (E.g., "*SC + termination address" as a forwarded-to number, or Priority Service invocation through other re-direction services, such as IN DP12 Redirection etc.) Call Origination Restrictions Priority Service shall override Call origination Restrictions for Barring of Outgoing Calls (BAOC), Barring of outgoing International Calls (BOIC) and Barring of Outgoing International Calls except to Home PLMN Country (BOIC-exHC), as a network option. Note: This may be necessary only for the PIN-based solution. eMLPP (USA regional requirement) Priority Service call attempt shall override any eMLPP priority levels that may be received from eMLPP capable mobile phones. That is Priority Service users shall be able to only invoke their assigned priority level. If a Priority Service user has an eMLPP capable phone and attempts to use an eMLPP priority level in addition to Priority Service *SC dialing, the eMLPP priority level request will be ignored by the network. Prepaid service Priority Service applies only to post-paid calls. Users shall not be allowed to subscribe to Priority Service and Prepaid. Emergency Calls (USA regional requirement) There is no interaction between Priority Service and emergency calls. If a service user dials *SC + [emergency call number], the call either receives radio traffic channel priority access treatment based on the service user's priority level or the call is denied. If a non-service user dials *SC + [emergency call number], the call is denied.