Apparatus, systems and methods for improved mobility between networks

1. A method, comprising:

at a user equipment (“UE”) in communication with a cellular network:

activating a detach timer for the cellular network, wherein the detach timer indicates a time until the UE detaches from the cellular network;

communicating with a short-range network;

storing registration and bearer context data related to the cellular network;

while in communication with the short-range network, discontinuing communication with the cellular network;

prior to discontinuing communication with the cellular network and in response to communicating with the short-range network, initiating, by the UE, a Radio Resource Control (“RRC”) protocol connection with the cellular network, wherein the RRC protocol connection causes the detach timer to reset to an initial value; and

prior to the expiration of the detach timer, reconnecting to the cellular network via a service request using the stored registration and bearer context data without using an attach procedure.

2. The method of claim 1 , further comprising:

transmitting, by the UE, a timer extension request to the cellular network to extend a duration of the detach timer; and

receiving, by the UE, a new timer value from the cellular network to extend the duration of the detach timer.

3. The method of claim 1 , further comprising:

transmitting, by the UE, an exit indication to the cellular network informing the cellular network that the UE will transition to the short-range network.

4. The method of claim 1 , wherein the discontinuing the communication with the cellular network includes powering down a cellular transceiver of the UE and reconnecting to the cellular network includes powering up the cellular transceiver.

5. The method of claim 1 , wherein the discontinuing the communication with the cellular network includes exiting a range of a cellular transceiver and reconnecting to the cellular network includes returning within the range of the cellular transceiver.

6. The method of claim 1 , wherein the short-range network is one of a WiFi network and a Bluetooth network.

7. The method of claim 1 , wherein the detach timer is one of a periodic tracking area update (“TAU”) timer and a periodic routing area update (“RAU”) timer.

8. The method of claim 1 , wherein the time until the UE detaches from the cellular network comprises a time until the UE performs a detach procedure to detach from the cellular network.

9. A user equipment (“UE”) device, comprising:

a memory arrangement;

a cellular transceiver configured to communicate with a cellular network;

a non-cellular transceiver configured to communicate with a short-range network;

a detach timer; and

a processor that activates the detach timer for the cellular network and stores registration and bearer context data related to the cellular network when the UE discontinues communication with the cellular network and connects to the short-range network,

wherein, prior to discontinuing communication with the cellular network and in response to communicating with the short-range network, the processor initiates a Radio Resource Control (“RRC”) protocol connection with the cellular network, wherein the RRC protocol connection causes the detach timer to reset to an initial value;

wherein the detach timer indicates a time until the UE detaches from the cellular network; and

wherein prior to the expiration of the detach timer, the cellular transceiver reconnects to the cellular network via a service request using the stored registration and bearer context data without using an attach procedure.

10. The UE device of claim 9 , wherein the cellular transceiver transmits a timer extension request to the cellular network to extend a duration of the detach timer and receives a new timer value from the cellular network, wherein the processor extends the duration of the detach timer based on the new timer value.

11. The UE device of claim 9 , wherein the cellular transceiver transmits an exit indication to the cellular network informing the cellular network that the UE will transition to the short-range network.

12. The UE of claim 9 , wherein the discontinuing the communication with the cellular network includes one of:

powering down the cellular transceiver of the UE and reconnecting to the cellular network includes powering up the cellular transceiver, and

exiting a range of the cellular transceiver and reconnecting to the cellular network includes returning within the range of the cellular transceiver.

13. The UE of claim 9 , wherein the non-cellular transceiver is one of a WiFi modem or a Bluetooth modem.

14. An integrated circuit in communication with a non-volatile computer-readable medium that stores instructions that, when executed by the integrated circuit, cause the integrated circuit to perform operations including:

activating a detach timer for a cellular network, wherein the detach timer indicates a time until a UE detaches from a cellular network;

communicating with a short-range network;

storing registration and bearer context data related to the cellular network;

while in communication with the short-range network, discontinuing communication with the cellular network;

prior to discontinuing communication with the cellular network and in response to communicating with the short-range network, initiating, by the UE, a Radio Resource Control (“RRC”) protocol connection with the cellular network, wherein the RRC protocol connection causes the detach timer to reset to an initial value; and

prior to the expiration of the detach timer, reconnecting to the cellular network via a service request using the stored registration and bearer context data without using an attach procedure.

15. The integrated circuit of claim 14 , wherein the integrated circuit further performs operations comprising:

transmitting a timer extension request to the cellular network to extend a duration of the detach timer; and

receiving a new timer value from the cellular network to extend the duration of the detach timer.

16. The integrated circuit of claim 14 , wherein the integrated circuit further performs operations comprising:

transmitting an exit indication to the cellular network informing the cellular network that the UE will transition to the short-range network while registration and bearer context data related to the cellular network.

17. The integrated circuit of claim 14 , wherein the discontinuing the communication with the cellular network includes one of:

powering down a cellular transceiver of the UE and reconnecting to the cellular network includes powering up the cellular transceiver, and

exiting a range of the cellular transceiver and reconnecting to the cellular network includes returning within the range of the cellular transceiver.

18. The integrated circuit of claim 14 , wherein the short-range network is one of a WiFi network and a Bluetooth network.