Patent Application
20170142566
This application claims the priority benefit of Taiwan application serial no. 104137320, filed on Nov. 12, 2015. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.
1. Field of the Disclosure
The disclosure is related to a mobile communication technique, and more particularly, to a control method of emergency call and user equipment using the same.
2. Description of Related Art
Along with rapid development of mobile communication technique, people can use user equipments (UEs) (e.g., smart phones, notebook computers, tablet computers, etc.) to make phone calls, send messages or access the Internet at anytime and anywhere, or can even access video and audio streaming services (for example, to listen to music or watch movies, etc.) requiring a high transmission bandwidth or high transmission speed.
On the other hand, emergency call service is a sort of emergency service which is available in mobile communication technique for people calling police, fire station or hospital in an emergency distress. In some conditions, even without having to insert a Universal Integrated Circuit Card (UICC) (e.g., Subscriber Identity Module (SIM) card, Universal Subscriber Identity Module (USIM) card, etc.), or without having to unlock the locked state of the user equipment, people can still seek help or rescue through directly dialing the direct dial numbers (e.g., 112, 999, etc.).
Generally, when the UE camps on a suitable cell and obtains a normal service, then an emergency call can be initiated. However, in some circumstances, the signal strength or the signal quality received from a serving cell of the current Public Land Mobile Network (PLMN) may be poor, thus the UE cannot successfully establish a connection. Then, the UE might continue to select this serving cell, such that the call failure may continue to occur.
Specifically,
Next, if a suitable cell is found in the cell selection procedures executed in States 101 and 103, the UE enters in state Camped normally (State 105) and camps on this suitable cell. In State 105, the UE obtains a normal service (e.g., answering an incoming call or initiating a call, etc.). The UE enters Connected mode (State 108) in order to make a call, and the UE enters Cell selection procedure (State 109) when leaving the state Connected mode. In addition, in order to select a better suitable cell, the UE enters Cell reselection procedure (State 107).
On the other hand, if no suitable cell is found or if a necessary NAS registration on selected PLMN is rejected (except with cause #12: location area not allowed; #14: General Packet Radio Service (GPRS) not allowed in this PLMN; #15: no suitable cell existing in location area or #25: Closed Subscriber Group (CSG) unauthorized), then the UE enters Any cell selection (State 111), and shall attempt to camp on an acceptable cell of any PLMN.
If an acceptable cell is found in the any cell selection procedure executed in State 111, then the UE enters Camped on any cell (State 113), and camps on the acceptable cell. The UE may initiate an emergency call so as to enter Connected mode (State 117). UE will enter Cell selection procedure (State 119) after leaving Connected mode. In addition, in order to select a better acceptable cell, the UE may enter the state Cell reselection procedure (State 115). In addition, in State 113, the UE may also continue to attempt to find a suitable cell, and return to State 105 after a suitable cell is found.
It should be noted that, a suitable cell indicates that this cell fulfils the requirements of belonging to the selected PLMN, not being barred, cell selection criteria, and so on, and the UE camping on the suitable cell would obtain a normal service. An acceptable cell indicates that this cell fulfils the minimum set of requirements to initiate an emergency call, receive Earthquake Tsunami Warning System (ETWS) notification, receive Commercial Mobile Alert System (CMAS) notification, and so on, and the UE camps on the acceptable cell and may merely obtain a restricted service (e.g., initiating an emergency call, receiving ETWS or CMAS notifications).
Assuming that the UE initiates an emergency call in State 105, it shall attempt to access the current serving cell so as to enter Connected mode (State 108). If attempting to access the serving cell is failed, then the UE may enter Cell reselection evaluation procedure (State 107). Assuming that a poor signal strength and signal quality causes the emergency call before entering State 108 failed (e.g., Radio Resource Control (RRC) connection establishing failed, and the like), since not under the RRC connected mode, the UE might not attempt to enter RRC to re-establish, thus the UE may return to RRC idle mode and performs cell reselection procedure. However, the serving cell may be selected again, and the emergency call triggered by the upper layer may also be failed again. In this circumstance, the UE may remain on this serving cell with poor signal strength or signal quality, and to attempt to originate an emergency call may continue to be failed.
The disclosure provides a control method of emergency call and user equipment using the same, capable of effectively avoiding the abovementioned problem that attempting an emergency call is continued to fail.
The disclosure provides a control method of emergency call, adapted to a user equipment (UE). The control method includes the following steps. In a first Public Land Mobile Network (PLMN), an emergency call is originated. Whether a radio resource related failure indication is received is determined. In response to the failure indication being received, one of second PLMNs supported by the user equipment is selected, and the emergency call is originated again.
The disclosure provides a UE, and the user equipment includes a transceiver module, a storage unit and a processing unit. The transceiver module transmits and receives wireless signals. The storage unit records modules. The processing unit couples the transceiver module and the storage unit, and accesses and executes the modules recorded by the storage unit. The modules include a radio resource control module and a call control module. In a first PLMN, the call control module originates an emergency call, and determines whether a failure indication from the radio resource control module is received or not. In response to the failure indication being received, the call control module selects one of second PLMNs supported by the user equipment, and originates the emergency call again.
In light of the above, the control method of emergency call and user equipment using the same of the disclosure determines whether the radio resource control module responds to the failure indication in the originating emergency call procedure, so as to reselect any supportable cell of PLMN, and originates the emergency call again. As such, the user equipment can automatically, effectively and successfully establish an emergency call, and the user being unable to send out a distress message through emergency call may effectively be avoided.
To make the above features and advantages of the disclosure more comprehensible, several embodiments accompanied with drawings are described in detail as follows.
The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure.
In some circumstances, although a call cannot be successfully established on a current serving cell, cells of other public land mobile networks (PLMNs) adjacent to the user equipment may have a better signal strength and signal quality. In the present embodiment of the disclosure, in the procedure of originating an emergency call on the current serving cell, according to whether a failure indication (e.g., a lower layer failure indication) related to the radio resource is received or not, an acceptable cell is reselected in any one of the PLMNs supported by the user equipment. Then, after the acceptable cell is camped on, the user equipment originates the emergency call again. Therefore, in the present embodiment, a probability of successfully establishing an emergency call would be elevated. Reference will now be made to the present preferred embodiments of the disclosure, and it will be apparent to those skilled in the art that adjustments and applications can be correspondingly made to the following embodiments based on demands instead of being limited by the content in the following description.
The term “user equipment” (UE) (such as UE 100) in this disclosure could represent various embodiments which for example could include but not limited to a mobile station, an advanced mobile station (AMS), a server, a client, a desktop computer, a laptop computer, a network computer, a workstation, a personal digital assistant (PDA), a tablet personal computer (PC), a scanner, a telephone device, a pager, a camera, a television, a hand-held video game device, a musical device, a wireless sensor, and so like.
The storage unit 150 may be any type of fixed or movable random access memory (RAM), a read-only memory (ROM), a flash memory or other similar devices or a combination of the above devices. In the embodiment, the storage unit 150 is adapted to store programming codes, device configurations, a codebook, buffered or permanent data, and adapted to record software programs including radio resource control (RRC) module 151, mobility management (MM) module 153, call control (CC) module 155, and so forth. In the present embodiment, the storage unit 150 is not limited to be one single memory device, and the abovementioned software modules may also be stored separately in two or more of memory devices of the same or different types.
The RRC module 151 is adapted to perform the functions such as broadcasting information related to NAS and AS, establishment, maintenance and release of RRC connection between the UE and the radio access network (RAN), assignment, reconfiguration and release of radio resources for RRC connection, initial cell selection and cell reselection procedures, and corresponds to the RRC sub-layer in communication protocol stack. The MM module 153 is adapted to support the mobility (e.g., report the network of the current location, provide user identification confidentiality) of UE 100, and adapted to provide connection management service to the Connection Management (CM) layer, and corresponds to the MM sub-layer in communication protocol stack. The CC module 155 is adapted for performing call procedures related to CC communication protocol such as call origination, call termination, and the like, and corresponds to the CM control sub-layer in communication protocol stack.
The processing unit 160 is configured for processing digital signals and performing a control method of an emergency call in accordance with the exemplary embodiments of the disclosure. In addition, the processing unit 160 may be coupled to the storage unit 150, so as to access and load the modules (e.g., RRC module 151, MM module 153, CC module 155, etc.) recoded by the storage unit 150. The functions of the processing unit 160 could be implemented by using programmable units such as a micro-processor, a micro-controller, a digital signal processing (DSP) chips, a field programmable gate array (FPGA), etc. The functions of the processing unit 160 may also be implemented with separate electronic devices or integrated circuits (ICs), and the processing unit 160 may also implement either hardware or software.
The term “base station” (such as the base stations 170_1-170_4) in this disclosure could represent various embodiments which for example could include (but not limited to) a Home Evolved Node B (HeNB), an eNB, an advanced base station (ABS), a base transceiver system (BTS), an access point, a home base station, a relay station, a scatterer, a repeater, an intermediate node, an intermediary, and/or satellite-based communications base stations. In the embodiment, each of the base stations 170_1-170_4 may support the same or different radio access technology (RAT) (e.g., the second generation (2G), the third generation (3G) or the fourth generation (4G) mobile communication technology or other voice call acceptable communication technology), or may belong to different PLMNs.
In order to facilitate understanding of an operation flow of the disclosure, a plurality of embodiments is provided below to describe a control method of the UE 100 performing an emergency call of the disclosure in detail.
In step S410, the processing unit 160 originates an emergency call through the CC module 155 in a first public land mobile network (PLMN). Assuming in a circumstance, the UE 100 is inserted an USIM card which supports the first PLMN, and camps on a cell (for the sake of convenience of illustration, hereinafter “serving cell”) of the base station 170_1 of
In the step S420, the processing unit 160 determines whether a failure indication related to the radio resources from the RRC module 151 is received or not through the CC module 155. In the present embodiment, the failure indication is a lower layer failure indication of the CC module 155. The lower layer failure indication may refer to a logical link failure, a radio resource sub-layer failure, from RRC sub-layer to GPRS Mobility Management (GMM) sub-layer failure, or the like. For example, the RACH failure. Generally, the error of the failure indication cannot be corrected by the lower layer (e.g., the RRC module 151, the radio link control (RLC) module, etc.). In the embodiment, the circumstance that a failure indication is received is deemed as signal strength and signal quality transmitted by the serving cell is poor, and may cause the attempt of the call failed. In response to the failure indication being not received, the UE 100 then may successfully establish an emergency call, and enter the connected mode (State 108 in
On the other hand, in the step S430, in response to the failure indication being received, the call control module 155 selects one of the second PLMNs supported by the UE 100, and originates the emergency call again. In one embodiment, the RRC module 151 initiates finding an acceptable cell of any one of the second PLMNs, so as to perform a camping procedure, and the CC module 155 originates the emergency call again on the acceptable cell that has completed the camping procedure.
Specifically, referring to
If an acceptable cell is found (e.g., the base station 170_3 in
In addition, in response to the failure indication being received, the RRC module 151 disables the cell reselection procedure in the first PLMN. In other words, the user may omit the normal cell reselection procedure (e.g., State 107 in
On the other hand, in response to the failure indication being received, if the acceptable cell is not found, the CC module 155 does not attempt to originate the emergency call. In one embodiment, the RRC module 151 initiates finding a suitable cell, so as to perform the camping procedure, and in response to the suitable cell not being found, performs a stored information cell selection procedure so as to find the suitable cell. Specifically, in the any cell selection procedure (e.g., State 111 in
Next, if the suitable cell is still not found, then the processing unit 160 may use the stored information cell selection procedure so as to find the suitable cell. In this circumstance, the processing unit 160 might not attempt to originate the emergency call again through the CC module 155. For instance, the processing unit 160 may, for example, transmit an error message to the upper layer (e.g., the application program, a driver, etc.), and interrupts the emergency call.
In addition, if the UE 100 is able to originate the emergency call again and successfully enter the connected mode (e.g., State 117 in
Specifically, after the call is ended in any PLMN (e.g., the UE 100 receiving a hang-up operation, or the connection being hang-up by the other, etc.), the UE 100 may return to the idle mode and selects the suitable cell to enter the camping procedure. For example, the UE 100 changes from State 117 to State 109 in
In other words, before attempting to originate the emergency call, the UE 100 is in the state camped normally. If the UE 100 causes the lower layer failed due to originating the emergency call (e.g., RACH failure) and triggers the performing any cell selection procedure (e.g., State 111 in
Accordingly, in the embodiment, in the condition that the signal strength and signal quality of the transmitted serving cell in the (automatically or manually) selected PLMN is poor and the attempt of the emergency call is failed, an acceptable cell in any other PLMNs is searched, so as to elevate a probability of successfully connecting an emergency call. In addition, after the acceptable cell is camped on, an emergency call is automatically originated in the present embodiment, so as to eliminate the tedious manual process.
For the sake of easily understanding said steps mentioned in above embodiments, another embodiment illustrating the operating procedures applied in the disclosure is described below.
In light of the foregoing, the control method of emergency call and user equipment using the same of the disclosure can, under the condition that the emergency call has failed due to the lower layer failure, find an acceptable cell in any one of other PLMNs, and originate the emergency call again after camping on the acceptable cell. Accordingly, in the embodiment of the disclosure, the problem that the UE remains on the worse serving cell and to attempt an emergency call continues to be failed can be avoided, further a probability of successfully establishing an emergency call would be significantly elevated.
Although the disclosure has been described with reference to the above embodiments, it will be apparent to one of ordinary skill in the art that modifications to the described embodiments may be made without departing from the spirit of the disclosure. Accordingly, the scope of the disclosure will be defined by the attached claims and not by the above detailed descriptions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 104137320 | Nov 2015 | TW | national |
