Evolved packet system quality of service enforcement deactivation handling to prevent unexpected user equipment detach

1. A method for preventing a detachment of a user equipment (UE) from a network, comprising:

determining, by a mobility management entity, that a default bearer between the UE and the network is a last default bearer connecting the UE to the network,

preventing deactivation of the default bearer between the UE and the network when at least one bearer between the UE and the network is to be deactivated based on a quality of service parameter,

wherein the default bearer and the at least one bearer are associated with a serving gateway,

wherein preventing deactivation of the default bearer between the UE and the network is accomplished by rejecting a request to deactivate the at least one bearer when deactivating the at least one bearer would result in an unexpected UE detachment from the network, and

wherein rejecting the request to deactivate the at least one bearer is implemented by the mobility management entity,

wherein the quality of service parameter of the UE is a priority level of the UE, and wherein a decision is made to deactivate the at least one bearer when the priority level of the UE is lower than a priority level of another UE connected to the network.

2. A mobility management entity, comprising:

a processor configured to prevent a detachment of a user equipment (UE) from a network by preventing deactivation of at least one default bearer between the UE and the network when at least one bearer between the UE and the network is to be deactivated based on a quality of service parameter,

wherein the at least one default bearer is an initial connection of the UE to the network,

wherein the quality of service parameter of the UE is a priority level of the UE,

wherein the priority level is based on service fees paid by the UE user,

wherein the at least one bearer is to be deactivated when the priority level of the UE is lower than a priority level of another UE connected to the network, and

wherein the at least one default bearer and the at least one bearer are associated with a serving gateway,

wherein the deactivation of at least one default bearer between the UE and the network is prevented by rejecting a request to deactivate the at least one bearer,

wherein rejecting the request to deactivate is performed by the mobility management entity.

3. The mobility management entity of claim 2 , wherein the mobility management entity prevents deactivation of at least one default bearer between the UE and the network by implementing a policy specifying that deactivation of default bearers is not allowed.

4. The mobility management entity of claim 3 , wherein the policy is provided by one of:

a packet data network gateway; and

a policy control and charging rules function.