# Patent

## Title
Method of managing mobility management layer of a mobile device

## Abstract

After a mobility layer of a mobile device enters a waiting state, a timer T3240 is activated. The mobile device is configured to await further instructions from a network system before the timer T3240 expires and control the mobility layer to leave the waiting state if the timer T3240 expires, thereby improving system efficiency.

## Background
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. provisional application No. 61/641,904 filed on May 3, 2012 and is a continuation-in-part of U.S. application Ser. No. 13/409,022 filed on 29 Feb. 2012, the entirety of which is incorporated by reference.


BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is related to a method of managing a mobility management layer in a mobile device, and more particularly, to a method of managing a mobility management layer in a mobile device with improved system efficiency.
2. Description of the Prior Art
According to 3GPP (3rd Generation Partnership Project) mobile communication structure, the wireless interface protocol structure of a mobile device includes three layers: a physical layer, a data link layer, and a network layer. The data link layer includes a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The network layer includes a radio resource control (RRC) layer, a mobility management (MM) layer and a connection management (CM) layer.
The RLC layer is configured to provide services including protocol data unit (PDU) transmission, automatic retransmission request (ARQ) correction, concatenation, service data unit (SDU) segmentation/reassembly/deletion, sequential PDU transmission, duplicative detection, protocol error detection, and protocol reestablishment.
The MAC layer is configured to provide services including hybrid automatic repeat request (HARQ) error correction and transmission time interval (TTI) bundling transmission.
The CM layer is configured to provide call controls, including establishing connection, selecting connection type (voice or fax) and releasing connection, and manage supplementary service (SS) and short message service (SMS).
The RRC layer is configured to maintain connection, establish/release communication channel, and manage power control.
The MM layer is configured to handle user verification, signal encoding and all mobility-related functions so that the network may be informed of the current location of the mobile device.
According to current 3GPP specifications, after entering State 9, the MM layer has a RR connection to its peer entity in the network, but no MM connection is established. The mobile device is passive, awaiting further commands from the network. In the prior art, if the network somehow fails to respond, the MM layer of the mobile device may stay in State 9 and thus is unable to provide other services.
SUMMARY OF THE INVENTION
The present invention provides a method of managing a mobility management layer in a mobile device. The method includes activating a timer of the mobile device after the mobility management layer enters a waiting state and the mobility management layer exiting the waiting state according to a command received from a network before the timer expires or the mobility management layer exiting the waiting state after the timer expires.
The present invention provides a method of managing a mobility management layer in a mobile device. The method includes activating a timer T3240 of the mobile device after the mobility management layer enters a state 9 “wait for network command” defined in a 3GPP specification; and the mobility management layer exiting the state 9 according to a command received from a network before the timer T3240 expires or the mobility management layer exiting the state 9 after the timer T3240 expires and entering a state 19 “MM idle”, defined in the 3GPP specification by releasing a radio resource connection.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a state diagram illustrating the operation of the MM layer in a mobile device according to the present invention.
FIG. 2 is a flowchart illustrating a method of operating the MM layer in a mobile device according to the present invention.



DETAILED DESCRIPTION
FIG. 1 is a state diagram illustrating the operation of the MM layer in a mobile device according to the present invention. FIG. 1 depicts state 3 “location updating initiated”, state 6 “MM connection activated”, state 7 “IMSI (international mobile subscriber identity) detach activated, state 9 “wait for network command”, state 19 “MM idle”, and state 25 “RR connection release not allow”. Since the present invention is related to the operation of state 9, only relevant states are depicted in FIG. 1. Other possible states of the MM layer are described and explained in related 3GPP specifications (such as TS 24.008).
FIG. 2 is a flowchart illustrating a method of operating the MM layer in a mobile device according to the present invention. The method includes the following steps:
Step 210: determine whether the MM layer is in a waiting state: if yes, execute step 220; if no execute step 210.
Step 220: activate a timer T3240 of the mobile device, execute step 230.
Step 230: determine whether the timer T3240 has expired: if yes, execute step 260; if no execute step 240.
Step 240: determine whether a specific command associated with exiting the waiting state is received from a network: if yes, execute step 250; if no execute step 230.
Step 250: exit the waiting state and perform a first action corresponding to the specific command, execute step 270.
Step 260: exit the waiting state and perform a second action, execute step 270.
Step 270: reset the timer T3240, execute step 210.
In step 210, the waiting state may be state 9 defined in related 3GPP specifications (such as TS 24.008). In state 9, the MM layer has a RR connection to its peer entity in the network, but no MM connection is established. The mobile device is passive, awaiting further commands from the network. In the embodiment illustrated in FIG. 1, the MM layer may enter state 9 after the mobile device performs actions A1-A4. Action A1 is “RR connection established” in response to paging. Action A2 is “last connection release”. Action A3 is “store system info”. Action A4 is “RR connection release not allowed”. If it is determined instep 210 that the MM layer has entered the waiting state (such as state 9), step 220 is executed for activating the timer T3240 of the mobile device, and step 230 is then executed for determining whether the timer T3240 has expired.
In step 220 of the present invention, the timer T3240 is started after the mobile device enters the waiting state when:

    
    
        the mobile device receives a LOCATION UPDATING ACCEPT message completing a location updating procedure;
        the mobile device receives a LOCATION UPDATING REJECT message;
        the mobile device has sent a CM SEARVICE ABORT message;
        the mobile device has released or aborted all MM connections; or
        the mobile device enters the waiting state after receiving the paging message from the network.
    
    


If it is determined in step 230 that the timer T3240 has not expired, step 240 is executed for determining whether the specific command associated with exiting the waiting state is received from the network. When receiving the specific command, step 250 is executed for exiting the waiting state and performing the first action corresponding to the specific command. In the embodiment illustrated in FIG. 1, the first action may be actions B1-B4. Action B1 is “RR connection release” according to a network command. Action B2 is “indicate MM connection” after receiving a first message. Action B3 is “MS (mobile station) deactivated and attach allowed”. Action B4 is “RR connection release not allow”.
If it is determined in step 230 that the timer T3240 has expired, step 260 is executed for exiting the waiting state and performing the second action. In the embodiment illustrated in FIG. 1, the second action may be action B5 “RR connection release” when the timer T3240 expires. After performing the second action, the mobile device may enter state 19 “MM idle”.
In the embodiment illustrated in FIG. 1, the MM layer of the mobile device may enter a specific state corresponding to the specific action after exiting the waiting state. For example, after exiting state 9, the mobile device may perform action B1 and enter state 19, perform action B2 and enter state 6, perform action B3 and enter state 7, perform action B4 and enter state 25, or perform action B5 and enter state 19. After the MM layer exits the waiting state in step 250 or 260, step 270 is then executed for resetting the timer T3240 before looping back to step 210.
In an embodiment when the mobile device enters state 9 “wait for network command” after receiving a paging message from the network, the timer T3240 is started. If the timer T3240 expires, the mobile device is configured to abort the RR connection and enter state 19 “MM idle”.
In the present invention, before the waiting period of the mobility management layer after entering a waiting state expires, the mobile device is configured to passively await further instructions from the network. After the waiting period of the mobility management layer after entering the waiting state expires, the mobile device is configured to control the MM layer to exit the waiting state. If the network somehow fails to respond, the MM layer of the mobile device may exit the waiting state for providing other services, thereby improving system efficiency.
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds Hof the appended claims.

## Claims

1. A method of managing a mobility management layer in a mobile device, comprising:
when receiving a paging message from a network, the mobility management layer entering a waiting state to establish a radio resource connection without establishing any mobility management connection;
activating a timer of the mobile device after the mobility management layer enters the waiting state;
the mobility management layer exiting the waiting state according to a command received from the network before the timer expires or the mobility management layer exiting the waiting state after the timer expires;
determining whether the command associated with exiting the waiting state is received from the network if the timer does not expire; and
the mobility management layer exiting the waiting state and performing a specific action corresponding to the command when receiving the command,
wherein the specific action includes an “RR (radio resource) connection release” action, an “indicate MM (mobility management) connection” action, an “MS (mobile station) deactivated and attach allowed” action, or an “RR connection release not allow” action.

2. The method of claim 1, wherein the mobile device performs the specific action when receiving the command before the timer expires, and the mobility management layer enters a state 3 “location updating initiated”, a state 6 “MM connection activated”, a state 7 “IMSI (international mobile subscriber identity) detach activated, a state 9 “wait for network command”, a state 19 “MM idle”, and a state 25 “RR connection release not allow” defined in a 3GPP (the 3rd Generation Partnership Project) specification 24.008 rel-11.2.

3. The method of claim 1, wherein the timer is a timer T3240 defined in a 3GPP specification 24.008rel-11.2.

4. The method of claim 1, wherein the waiting state is a state 9 “wait for network command” defined in a 3GPP specification 24.008 rel-11.2.

5. The method of claim 4, further comprising:
the mobility management layer exiting the waiting state and releasing the radio resource connection if the timer expires.

6. The method of claim 5, further comprising:
the mobility management layer entering a state 19 “MM idle”, and a state 25 “RR connection release not allow” defined in a 3GPP specification after releasing the radio resource connection.

7. A method of managing a mobility management layer in a mobile device, comprising:
when receiving a paging message from a network, the mobility management layer entering a state 9 “wait for network command” defined in a 3GPP specification 24.008 rel-11.2;
activating a timer T3240 of the mobile device after the mobility management layer enters the state 9; and
the mobility management layer exiting the state 9 according to a command received from the network before the timer T3240 expires or the mobility management layer exiting the state 9 after the timer T3240 expires and entering a state 19 “MM idle” defined in the 3GPP specification 24.008 rel-11.2 by releasing the radio resource connection;
determining whether the command associated with exiting the state 9 is received from the network if the timer T3240 does not expire; and
the mobility management layer exiting the state 9 and performing a specific action corresponding to the command when receiving the command,
wherein the specific action includes an “RR (radio resource) connection release” action, an “indicate MM (mobility management) connection” action, an “MS (mobile station) deactivated and attach allowed” action, or an “RR connection release not allow” action.