EP2932742A1

EP2932742A1 - Emergency call in communication device

Info

Publication number: EP2932742A1
Application number: EP12809232.7A
Authority: EP
Inventors: Rama Kumar Mopidevi; Jakob Singvall
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2012-12-14
Filing date: 2012-12-14
Publication date: 2015-10-21
Also published as: WO2014090340A1; CN104365124A

Abstract

Communication device (210) and method (500), configured for multiple subscriber identities (640-1, 640-2, 640-n), comprising at least a first subscriber identity (640-1) and a second subscriber identity (640-2), for making an emergency call. The method (500)comprises receiving (501) a user input value, indicating that an emergency call is desired, determining (502) the subscriber identity (640-1, 640-2, 640- n) having the best signal quality, and for establishing (503) the emergency call on the subscriber identity (640-1, 640-2, 640-n) determined (502) to have the best signal quality.

Description

EMERGENCY CALL IN COMMUNICATION DEVICE

TECHNICAL FIELD

Implementations described herein relate generally to a communication device and a method in a communication device. In particular is herein described a mechanism for making an emergency call in a communication device comprising at least two subscriber identities.

BACKGROUND A communication device, also known as User Equipment (UE) , mobile station, wireless terminal, receiver and/or mobile terminal is enabled to communicate wirelessly in a wireless communication system, sometimes also referred to as a cellular radio system. The communication may be made e.g. between two communication devices, between a communication device and a wire connected telephone and/or between a communication device and a server via a Radio Access Network (RAN) and possibly one or more core networks .

The communication device may further be referred to as mobile telephone, cellular telephone, computer tablet or laptop with wireless capability. The communication devices in the present context may be, for example, portable, pocket-storable, hand^¬ held, computer-comprised, or vehicle-mounted mobile devices, enabled to communicate voice and/or data, via the radio access network, with another entity, such as another communication device or a server.

The wireless communication system covers a geographical area which is divided into cell areas, with each cell area being served by a radio network node, or base station e.g. a Radio Base Station (RBS) , which in some networks may be referred to as transmitter, "eNB", "eNodeB", "NodeB" or "B node", depending on the technology and terminology used. The radio network nodes may be of different classes such as e.g. macro eNodeB, home eNodeB or pico base station, based on transmission power and thereby also cell size. A cell is the geographical area where radio coverage is provided by the radio network node/ base station at a base station site. One radio network node, situated on the base station site, may serve one or several cells. The radio network nodes communicate over the air interface operating on radio frequencies with the communication devices within range of the respective radio network node.

In some radio access networks, several radio network nodes may be connected, e.g. by landlines or microwave, to a Radio Network Controller (RNC) e.g. in Universal Mobile Telecommunications System (UMTS) . The RNC, also sometimes termed Base Station Controller (BSC) e.g. in GSM, may supervise and coordinate various activities of the plural radio network nodes connected thereto. GSM is an abbreviation for Global System for Mobile Communications (originally: Groupe Special Mobile) .

In 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) , radio network nodes, which may be referred to as eNodeBs or eNBs, may be connected to a gateway e.g. a radio access gateway, to one or more core networks.

In the present context, the expressions downlink, downstream link or forward link may be used for the transmission path from the radio network node to the communication device. The expression uplink, upstream link or reverse link may be used for the transmission path in the opposite direction i.e. from the communication device to the radio network node.

Wireless Fidelity (Wi-Fi) , which also may be spelled Wifi, WiFi or WIFI, is a popular technology that allows the communication device to exchange data wirelessly over a computer network, including high-speed Internet connections. The Wi-Fi Alliance defines Wi-Fi as any "Wireless Local Area Network (WLAN) products that are based on the Institute of Electrical and Electronics Engineers' (IEEE) 802.11 standards. A communication device that is configured to use Wi-Fi such as e.g. a personal computer, video game console, smartphone, tablet, or digital audio player. The communication device in the present context may be, for example, portable, pocket- storable, hand-held, computer-comprised, or vehicle-mounted mobile devices, enabled to communicate voice and/or data, via the radio access network, with another entity, such as another device, a radio network node or a server. The communication device may connect to a network resource such as the Internet via a wireless network access point. Such an access point, or hotspot as it also may be referred to, may have a range of about 20 meters (65 feet) indoors and a greater range outdoors. Hotspot coverage may comprise an area as small as a single room with walls that block radio waves or as large as many square miles, which may be achieved by using multiple overlapping access points.

In a Wi-Fi enabled device, the communication device needs to search for networks to be able to connect, in order to perform e.g. a Voice over the Internet Protocol (VoIP) call.

A communication device may sometimes comprise at least two subscriber identities, such as Subscriber Identity Modules (SIMs) . Such a communication device may occasionally be referred to as a Multiple SIM phone. Each subscriber identity/SIM of such communication device may be associated with a modem that is configured for communication over a certain access technology, such as GSM, UMTS, LTE etc, and/or a Voice over the Internet Protocol (VoIP) , such as Skype or Google voice.

However, one or more of the subscriber identities may be considered primary subscriber identity and the rest of the subscriber identities are considered secondary subscriber identities.

Generally the user may select which subscriber identity is primary depending on a cost plan.

A communication device according to prior art is schematically illustrated in Figure 1. When a telephone call is to be made, the call is placed on the primary subscriber identity, which in the illustrated example is SIM 2, even though the other subscriber identities might have better signal quality, unless the primary subscriber identity (in this case SIM 2) is out of coverage. In such case, the call is instead placed on a secondary subscriber identity in a predefined prioritization order, usually depending on the cost plan.

In emergency situations, when an emergency call is to be made, there is a risk that the emergency call suffers from unacceptable voice quality or is dropped due to deteriorating signal level, for example, when the emergency call is made on the primary subscriber identity, which may have been selected as the primary subscriber identity of e.g. economic reasons.

SUMMARY It is therefore an object to obviate at least some of the above mentioned disadvantages and to improve the performance in a communication infrastructure.

According to a first aspect, the object is achieved by a method in a communication device, configured for multiple subscriber identities. The communication device may comprise at least a first subscriber identity and a second subscriber identity, for making an emergency call. The method comprises receiving a user input value, indicating that an emergency call is desired. Also, the method comprises determining the subscriber identity having the cell with the best signal quality. Furthermore, the method in addition comprises establishing the emergency call on the subscriber identity determined to have the cell with the best signal quality.

According to a second aspect, the object is achieved by a communication device, for multiple subscriber identities, comprising at least a first subscriber identity and a second subscriber identity, configured for making an emergency call. The communication device comprises a user interface, configured for receiving a user input value, indicating that an emergency call is desired. Further, the communication device also comprises a processing circuit, configured for determining the subscriber identity having the cell with the best signal quality. The communication device in addition comprises a transmitter, configured for establishing the emergency call on the subscriber identity determined to have the cell with the best signal quality.

Embodiments herein concern a communication device that comprises at least two subscription identities. Some advantages according to some embodiments comprises that an emergency call may be established on the subscription identity that has the best signal quality, regardless if that subscription identity is selected as primary subscription identity, or not. Such scenario may appear for example when the user has selected a first subscription identity as primary subscription identity for cost reasons, while having a second subscription identity which may be subject to roaming, or otherwise be more expensive, but having a better signal quality .

Thanks to herein described embodiments, emergency calls may be made on the best available connection the communication device has access to, which reduces the risk of dropping the connection. Also, the best possible voice quality is provided during the emergency call, which reduces the risk of misunderstandings. Thereby, life and/or property may be saved; or alternatively, damages may be reduced as misunderstandings take time which may be valuable in an emergency situation. Thus an improved performance within a communication infrastructure is provided.

Other objects, advantages and novel features of the described embodiments of the invention will become apparent from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are described in more detail with reference to attached drawings illustrating examples of embodiments in which:

Figure 1 is a block diagram illustrating a multi SIM communication device according to prior art. Figure 2 is a block diagram illustrating an infrastructure overview wherein the invention is implemented.

Figure 3 is a block diagram illustrating a communication device according to an embodiment of the invention. Figure 4 is a combined flow chart and signalling diagram, illustrating an embodiment of the invention.

Figure 5 is a flow chart illustrating a method in a communication device according to an embodiment of the invention. Figure 6 is a block diagram illustrating a communication device according to an embodiment of the invention.

DETAILED DESCRIPTION

Embodiments of the invention described herein are defined as a communication device and a method in a communication device, which may be put into practice in the embodiments described below. These embodiments may, however, be exemplified and realised in many different forms and are not to be considered as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete.

Still other objects and features may become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the herein disclosed embodiments, for which reference is to be made to the appended claims. Further, the drawings are not necessarily drawn to scale and, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.

Figure 2 is a schematic illustration over a wireless communication infrastructure 200.

The illustration in Figure 2 comprises a communication device 210 and network nodes 220-1, 220-2, 220-3. The network node 220-1, 220-2, 220-3 may comprise a cellular radio network node or an access point of a wireless local area network. Further, an emergency telephone switchboard 230 is illustrated. The emergency telephone switchboard 230 may also sometimes be referred to as a Public Service Answering Point (PSAP) , a telephone operator and/or an emergency service dispatcher.

The wireless communication infrastructure 200 may at least partly comprise one or more cellular radio networks, which in turn may be based on the same or different radio access technologies such as e.g. 3GPP LTE, LTE-Advanced, Evolved Universal Terrestrial Radio Access Network (E-UTRAN) , Universal Mobile Telecommunications System (UMTS) , Global System for Mobile Communications (originally: Groupe Special Mobile) (GSM)/ Enhanced Data rate for GSM Evolution (GSM/EDGE) , Wideband Code Division Multiple Access (WCDMA) , Worldwide Interoperability for Microwave Access (WiMax) , or Ultra Mobile Broadband (UMB) , High Speed Packet Access (HSPA) Evolved Universal Terrestrial Radio Access (E-UTRA) , Universal Terrestrial Radio Access (UTRA) , GSM EDGE Radio Access Network (GERAN) , 3GPP2 CDMA technologies e.g. CDMA2000 lx RTT and High Rate Packet Data (HRPD) , just to mention some few options.

Any cellular radio network may be configured to operate according to the Time Division Duplex (TDD) and/or the Frequency Division Duplex (FDD) principle, according to different embodiments.

TDD is an application of time-division multiplexing to separate uplink and downlink signals in time, possibly with a Guard Period situated in the time domain between the uplink and downlink signalling. FDD means that the transmitter and receiver operate at different carrier frequencies, as have previously been discussed.

Different network nodes 220-1, 220-2, 220-3 may thus be working on different radio access technologies and the communication device 210 may be connectable to one or more of these network nodes 220-1, 220-2, 220-3 by using different radio access technologies associated with a subscriber identity/ SIM comprised in the communication device 210 according to some embodiments. However, several subscriber identities/ SIMs comprised in the communication device 210 may be associated with the same radio access technology, according to some embodiments.

Further, such communication device 210 comprising at least two subscriber identities/ SIMs may be referred to as a Multiple SIM phone. Each subscriber identity/SIM of such communication device 210 may be associated with a modem that is configured for communication over a certain access technology, such as GSM, UMTS, LTE etc, and/or a Voice over the Internet Protocol (VoIP), such as Skype or Google voice.

The purpose of the illustration in Figure 2 is to provide a simplified, general overview of the methods and nodes, and the functionalities involved. The method and communication device 210 will subsequently, as a non-limiting example, be described in a 3GPP environment, but the embodiments of the disclosed methods, radio network node and receiver may operate in a wireless communication system based on another access technology such as e.g. any of the above enumerated. Thus, although the embodiments of the invention are described based on, and using the lingo of, 3GPP systems, it is by no means limited to 3GPP.

The wireless local area network, or WLAN, may be a Wireless Fidelity (Wi-Fi) , as defined by any of Institute of Electrical and Electronics Engineers (IEEE) standards 802.11 a, b, g and/or n. The Wi-Fi network is configured to exchange data wirelessly, using radio waves over a computer network, including high-speed Internet connections. It is to be noted that the expressions wireless local area network and/or Wi-Fi may be used somewhat interchangeably with each other within the current context . The communication device 210 is configured for communication both over the cellular radio communication network via the network node 220-1, 220-2, 220-3 comprising a cellular radio network node, and over the wireless local area network via the network node 220-1, 220-2, 220-3 comprising an access point. Further, the communication device 210 may comprise, or be represented by, a User Equipment (UE) , a wireless communication terminal, a mobile cellular phone, a Personal Digital Assistant (PDA) , a wireless platform, a mobile station, a portable communication device, a laptop, a computer, a wireless terminal acting as a relay, a relay node, a mobile relay, a Customer Premises Equipment (CPE) , a Fixed Wireless Access (FWA) node, a personal computer, a video game console, a smartphone, a tablet, a digital audio player or any other kind of device configured to communicate wirelessly with the network node 220-1, 220-2, 220-3 comprising the cellular radio network node or the access point, according to different embodiments and different vocabulary. The communication device 210 is configured to establish a telephone call, in particular an emergency telephone call, to be received by the emergency telephone switchboard 230 via any of the network nodes 220-1, 220-2, 220-3, which may comprise cellular radio network nodes and/or Wi-Fi access points.

The emergency telephone call referred to herein may concern a telephone call for achieving assistance and/or help from police, medically trained personnel, fire department, National Gendarmerie, tourist police, coast guard, support for children, traffic police, counter terrorist unit, missing person report hotline, civil defence, motorist assistance, rescue emergency, accident service, alpine rescue, crisis- hotline, search and rescue at sea, forest fire, emergency social aid, counter-narcotics immediate intervention, Mountain and Cave Rescue, Carabinieri/ Civil Guard, Child-Abuse and Family Violence, Helicopter air-rescue and/or Psychological support, here mentioned merely as examples of such emergency telephone numbers.

Even though the expression emergency telephone call is utilised herein, the invention is not confined neither to telephones nor to voice calls. The invention may be exercised by any communication device 210 configured for making any emergency related connection to an emergency telephone switchboard 230. For example, according to some embodiments the invention may be exercised by a communication device 210 comprising a computer tablet, or other similar device sending a Short Message Service (SMS) message, a Multimedia Messaging Service (MMS) , a Video Message Service (VMS) , an Enhanced Messaging Service (EMS) , an e-mail, a video telephony call or similar means of communication. It is to be noted that the illustrated network setting of one communication device 210, one emergency telephone switchboard 230 and three network nodes 220-1, 220-2, 220-3 in Figure 2 is to be regarded as a non-limiting example of an embodiment only. The wireless communication system may comprise any other number and/or combination of network nodes 220-1, 220-2, 220-3 communication device 210 and/or emergency telephone switchboard 230, although only one instance of a communication device 210, one instance of a switchboard 230 and three network nodes 220-1, 220-2, 220-3, respectively, are illustrated in Figure 2, for clarity reasons. A plurality of communication devices 210, emergency telephone switchboards 230 and/or network nodes 220-1, 220-2, 220-3 may further be involved in some embodiments of the disclosed invention. Thus whenever "one" or "a/an" communication device 210, emergency telephone switchboard 230 and/or network node 220-1, 220-2, 220-3 is referred to in the present context, a plurality of communication devices 210, emergency telephone switchboards 230 and/or network nodes 220-1, 220-2, 220-3 may be involved, according to some embodiments.

The network node 220-1, 220-2, 220-3, when comprising a cellular radio network node, may according to some embodiments be referred to as e.g. base stations, NodeBs, evolved Node Bs (eNBs, or eNode Bs) , base transceiver stations, Access Point Base Stations, base station routers, Radio Base Stations (RBSs) , macro base stations, micro base stations, pico base stations, femto base stations, Home eNodeBs, sensors, beacon devices, relay nodes repeaters or any other network nodes configured for communication with the communication device 210 over a wireless interface, depending e.g. of the radio access technology and terminology used. The cellular radio network node controls the radio resource management within a cell, such as e.g. allocating radio resources to the communication device 210 within the cell and ensuring reliable wireless communication between the cellular radio network node and the communication device 210. The cellular radio network node may typically comprise an eNodeB, e.g. in an LTE-related wireless communication system.

The network node 220-1, 220-2, 220-3, when comprising an access point of the wireless local area network, which further may be referred to as a hotspot, may have a range of about 20 meters (65 feet) indoors and a somewhat greater range outdoors according to some embodiments. However, the access point may be based on IEEE standard 802.11b or 802. llg with a stock antenna and may have a range of 32 m (120 ft) indoors and 95 m (300 ft) outdoors. According to some further embodiments the access point may be based on IEEE standard IEEE 802.11η, however, may more than double the enumerated ranges.

Further, the communication device 210 comprises at least two subscriber identities, such as two Subscriber Identity Modules (SIMs) , or a multitude of an arbitrary number of SIMs. The respective subscriber identities may be configured for a particular radio access technology such as GSM, UMTS and/or LTE, according to some embodiments. However, the respective subscriber identities may be configured for a VoIP subscription in some embodiments. Thus the communication device 210 with multiple subscriptions in different embodiments may comprise a dual SIM, a triple SIM, a quad SIM, a penta SIM, a hexa SIM, a hepta SIM, an octa SIM, a nona SIM, a deca SIM, or just be referred to as a multi SIM comprising n subscription identities, where n is an arbitrary positive integer exceeding one. In some embodiments, the communication device 210 with multiple subscriptions may comprise a single SIM and a VoIP subscription, a dual SIM and a VoIP subscription, a triple SIM and a VoIP subscription, etc. Furthermore, in some alternative embodiments, the communication device 210 with multiple subscriptions may comprise two VoIP subscriptions, three VoIP subscriptions, n VoIP subscriptions, where n is an arbitrary integer.

The VoIP subscription/s may comprise e.g. Skype, Google Voice/ Google Talk, Gizmo5, Federated VoIP, AOL Instant Messenger, Blink, Bria, Cisco IP Communicator, Ekiga, Empathy, Eyeball Chat, eyeBeam, IBM Sametime, iCall, Jitsi, KPhone, Linphone, MicroSIP, Mirial Softphone, Mumble, Nymgo, oovoo, Phoner, PhonerLite, QuteCom, Revation Communicator, CommunicatorLive, SFLphone, SightSpeed, Spikko, TeamViewer, TeamSpeak, Tokbox, Toktumi Unlimited / Line2 Pro, Tru App, Twinkle, Vbuzzer, Ventrilo, Voice Operator Panel, X-Lite, Yahoo! Messenger, Yate, Zfone, Acrobits Groundwire, Acrobits Softphone, CSipSimple, Jajah Mobile Web, Line2, Sipdroid, Truphone, Vopium, Windows Mobile 6, X-PRO for Pocket PC, or any similar product implementation with similar functionality. According to some embodiments of the invention, the communication device 210 is configured for establishing an emergency telephone call to the emergency telephone switchboard 230.

The inventive concept comprises placing the emergency call on the subscriber identity/SIM that at the time for establishment of the emergency call has the best signal quality of the cell among all the cells associated with all the subscriber identities/SIMs . This minimizes the risk of dropped call in an emergency situation due to network overload or weak signal on the primary subscriber identity/SIM. Such signal quality may comprise, or be based on Reference Signal Received Power (RSRP) , Reference Signal Received Quality (RSRQ) , Received Signal Strength Indicator (RSSI) or any other appropriate measurement related to the signal propagation conditions in the radio interface between the communication device 210 and the network node 220-1, 220-2, 220-3.

Thereby, by placing the emergency call on the subscriber identity (SIM) that has the best signalling quality among all the subscriber identities (SIMs) , the best available voice quality is guaranteed during the emergency call, while the risk for dropped emergency calls is minimized, or at least reduced. Thereby, valuable time is saved as no re-calling may have to be made and the risk of misunderstandings or misinterpretation is reduced, which also save time, as the caller in the emergency situation does not have to repeat e.g. address information etc. Also, the risk of the emergency vehicle driving to the wrong address is reduced, which may save lives, and/or property.

Figure 3 is a block diagram illustrating a communication device 210 configured for multiple subscription identities, according to an embodiment of the invention.

A user 300 of the communication device 210 dials the numbers of an emergency call via a user interface, in case of an emergency call. The numbers of the emergency call may be country specific, and/or regional specific. Some examples of some such country specific, and/or regional specific emergency calls may comprise e.g. 911 in USA/Canada; 112 in (most) European countries; 999 in Great Britain; 000 in Australia;

111 in New Zeeland; 119 in North Korea; 102 in Belarus; 101 in Argentina; 190, 192 or 193 in Brazil, just to mention some arbitrary examples of such emergency numbers.

According to some embodiments, the momentary geographical position of the communication device 210 may be determined, and thereafter, the valid emergency number or emergency numbers in the determined momentary geographical position may be acquired from a list, which may be comprised in a memory within the communication device 210, and/or an external data base, according to some alternative embodiments. Further, the emergency call establishment may be indicated to an Emergency Call Coordinator, according to some alternative embodiments. The Emergency Call Coordinator may have knowledge of the signal quality of the cells associated with the modems, and thereby also with the subscription identities. The Emergency Call Coordinator may then find out that the cell belonging to subscription identity 1/SIM 1, which is associated with Modem 1 that has the best signal quality compared with the other subscription identities/SIMs/Modems . In order to get the best available connection for the emergency call, the emergency call establishment may be indicated to Modem 1, associated with subscription identity 1/ SIM 1, even if subscription identity 2/ SIM 2 is the primary subscription identity.

Having established that, the emergency call establishment procedure may be initiated over modem 1/ subscription identity 1.

The algorithm for selection of modem in the Emergency Call Coordinator, utilised above, may select the modem with the best signal quality. In order to minimize the impact on the modems, the existing cell selection algorithms for modems, for example as specified by 3GPP in 44.018, 45.008 (GSM), 25.133, 25.304, 25.331 (UMTS) and 36.304 (LTE) , may be reused in the Emergency Call Coordinator for selection of modem, according to some embodiments. Each modem may report the measured values for the selected cell, and the Emergency Call Coordinator may run the cell selection using those values, one set of cell values per modem, in order to select the best available connection. The reporting from the modem may be done continuously as required by the cell selection algorithm specified for the modem, and the Emergency Call Coordinator may be evaluating a new report using the cell selection algorithm according to some embodiments.

Figure 4 is a combined flow chart and signalling diagram, illustrating an embodiment of the invention. In Figure 4, the interactions between the user 300, the communication device 210 and the emergency telephone switchboard 230.

The illustrated communication device 210 comprises a first SIM and a second SIM, which however is merely an illustrative example. The communication device 210 may be a dual SIM phone or a multi SIM phone, according to different embodiments.

Each of the first SIM and the second SIM may be associated with the first modem and the second modem respectively. Thus the modems may monitor i.e. measure each respective signal strength and report the measured signal strength to a cell selection algorithm in a module, which may be referred to as the Emergency Call Coordinator. The reported parameters may be used in the cell selection algorithm in the Emergency Call Coordinator in order to select the cell/modem/subscription identity with best connection, i.e. operating on the cell with the best signal quality. This may be run continuously in some embodiments . Further, having selected the modem/ subscription identity with the cell with the best signal strength, when a user input value is detected, indicating that an emergency call is desired, the emergency call may be established on the modem/ subscription identity having the cell with the best signal quality .

The invention is not restricted to use the cell selection algorithm defined by 3GPP, nor to modems/ subscription identities defined by 3GPP. Any algorithm may be used for selection of any type of modem/ subscription identity.

According to embodiments herein, the best available connection may be selected for emergency calls in a communication device 210 comprising a Multiple SIM Phone or a dual SIM Phone. Thereby, the risk of dropped call is reduced while improving the speech quality.

Figure 5 is a flow chart illustrating embodiments of a method 500 for use in a communication device 210. The communication device 210 is configured for multiple subscriber identities, comprising at least a first subscriber identity and a second subscriber identity. Each of the multiple subscriber identities is associated with a respective modem.

The first subscriber identity and/or the second subscriber identity may comprise any of a Subscriber Identification Module "SIM" card, a Universal Integrated Circuit Card "UICC", a Universal Subscriber Identity Module "USIM", an Internet protocol multimedia Services Identity Module "I SIM", a Removable User Identity Module "R-UIM", a CDMA Subscriber Identity Module "CSIM", a Willcom-SIM "W-SIM" and/or a Voice over the Internet Protocol "VoIP" subscription, according to different embodiments.

The method 500 aims at making an emergency call over a wireless communication system 200, from the communication device 210 to be received by the emergency telephone switchboard 230 by dialling a national/regional emergency number. The wireless communication system 200 may comprise a cellular network based on any radio access technology of: Global System for Mobile Communications (GSM) , Enhanced Data Rates for GSM Evolution (EDGE), Universal Mobile Telecommunications System (UMTS) , Code Division Access (CDMA) , (CDMA 2000), Time Division Synchronous CDMA (TD-SCDMA) , Long Term Evolution (LTE) within the Third Generation Partnership Project (3GPP) , or possibly a similar radio access technology, in different embodiments. Further, the wireless communication system 200 may comprise a Wireless Fidelity (Wi-Fi) network, as defined by any of Institute of Electrical and Electronics Engineers (IEEE) standards 802.11 a, b, g and/or n.

The communication device 210 may be configured for radio communication with the cellular network, and/or for accessing the wireless local area network.

To appropriately make the emergency call over the wireless communication system 200, the method 500 may comprise a number of actions 501-503. It is however to be noted that any, some or all of the described actions 501-503, may be performed in a somewhat different chronological order than the enumeration indicates, or even be performed simultaneously. The method 500 may comprise the following actions: Action 501 A user input value is received over a user interface, indicating that an emergency call is desired.

The user interface may comprise a keyboard or similar device configured for receiving user input values, according to some embodiments.

The input value indicating that an emergency call is desired may comprise any national, regional or international emergency number such as e.g. 112, 911, 999 etc.

Action 502 The subscriber identity, having the cell with the best signal quality is determined.

The cell with the best signal quality may be determined based on: received signal quality, received signal strength, signal- to-noise ratio, Received Signal Code Power, ratio of received energy per bit to the interference "Ec/Io", number of dropped calls, Bit Error Rate "BER", or any other similar appropriate signal measurement value. Such signal measurement value may comprise, or refer to Reference Signal Received Power (RSRP) , Reference Signal Received Quality (RSRQ) , Received Signal Strength Indicator (RSSI) or any other appropriate measurement related to the signal propagation conditions in the radio interface between the communication device 210 and the emergency telephone switchboard 230.

The best signal quality may alternatively be determined by using any existing cell selection algorithm for modems, for example as specified by third Generation Partnership Project "3GPP" in 44.018, 45.008 for GSM, 25.133, 25.304, 25.331 for UMTS and/or 36.304 for LTE, according to some embodiments. According to some embodiments, the best signal quality may be determined by continuously monitoring the signal quality on each respective subscriber identity.

Action 503 The emergency call is established on the subscriber identity, determined 502 to have the cell with the best signal quality.

The emergency call may be established on the subscriber identity that is determined to have the cell with the best signal quality, irrelevant of whether that subscriber identity is the prioritized subscriber identity, according to some alternative embodiments.

Figure 6 is a block diagram illustrating a communication device 210. The communication device 210 is configured to establish an emergency call to an emergency telephone switchboard 230, via a network node 220.

The communication device 210 is further configured for multiple subscriber identities 640-1, 640-2, 640-n comprising at least a first subscriber identity 640-1 and a second subscriber identity 640-2, configured for making the emergency call. Each of the multiple subscriber identities 640-1, 640-2, 640-n is associated with a respective modem. The multiple subscriber identities 640-1, 640-2, 640-n may comprise n subscription identities, where n is an arbitrary positive integer, according to some embodiments.

The first subscriber identity 640-1 and/or the second subscriber identity 640-2 may comprise any of a Subscriber Identification Module "SIM" card, a Universal Integrated Circuit Card "UICC", a Universal Subscriber Identity Module "USIM", an Internet protocol multimedia Services Identity Module "ISIM", a Removable User Identity Module "R-UIM", a CDMA Subscriber Identity Module "CSIM", a Willcom-SIM "W-SIM" and/or a Voice over the Internet Protocol "VoIP" subscription, according to different embodiments.

The communication device 210 aims at performing the method 500, for making an emergency call over a wireless communication system 200, from the communication device 210 to be received by the emergency telephone switchboard 230 by dialling a national/regional emergency number. The wireless communication system 200 may comprise a cellular network based on any radio access technology of: Global System for Mobile Communications (GSM) , Enhanced Data Rates for GSM Evolution (EDGE), Universal Mobile Telecommunications System (UMTS), Code Division Access (CDMA), (CDMA 2000), Time Division Synchronous CDMA (TD-SCDMA) , Long Term Evolution (LTE) within the Third Generation Partnership Project (3GPP) , or possibly a similar radio access technology, in different embodiments. Further, the wireless communication system 200 may comprise a Wireless Fidelity (Wi-Fi) network, as defined by any of Institute of Electrical and Electronics Engineers (IEEE) standards 802.11 a, b, g and/or n.

The communication device 210 may be configured for radio communication with the cellular network, and/or for accessing the wireless local area network, for performing the different embodiments of the above described method 500 according to any, some or all of the actions 501-503.

To appropriately make the emergency call over the wireless communication system 200, the method 500 may comprise a number of actions 501-503. For enhanced clarity, any internal electronics or other components of the communication device 210, not completely indispensable for understanding the herein described embodiments has been omitted from Figure 6. The communication device 210 comprises a user interface 605, configured for receiving a user input value, indicating that an emergency call is desired.

The user interface 605 may comprise a keyboard, a keypad such as a numeric keypad, a text entry interface, a function key, a soft key, a thumb keyboard, a projection keyboard, a photo- optical keyboard, a light responsive keyboard, a photo^¬ electric keyboard, a stylus pen with a graphic tablet, a trackpad or any similar device.

Further, the communication device 210 comprises a processing circuit 620, configured for determining the subscriber identity 640-1, 640-2, 640-n having the cell with the best signal quality.

Furthermore, the processing circuit 620 may be additionally configured, according to some embodiments, for determining the best signal quality based on: received signal quality, received signal strength, signal-to-noise ratio, Received Signal Code Power, ratio of received energy per bit to the interference "Ec/Io", probability for dropped call, Bit Error Rate "BER", according to some embodiments. Also, the processing circuit 620 may be configured for determining the best signal quality by continuously monitoring the signal quality on each respective subscriber identity 640- 1, 640-2, 640-n. According to some embodiments, the best signal quality may be determined by using any existing cell selection algorithm for modems, for example specified by e.g. third Generation Partnership Project "3GPP" in 44.018, 45.008 (GSM), 25.133, 25.304, 25.331 (UMTS) and/or 36.304 (LTE) .

The processing circuit 620 may comprise e.g. one or more instances of a Central Processing Unit (CPU) , a processing unit, a processing circuit, a processor, an Application Specific Integrated Circuit (ASIC) , a microprocessor, or other processing logic that may interpret and execute instructions.

The herein utilised expression "processing circuit" may thus represent a processing circuitry comprising a plurality of processing circuits, such as e.g. any, some or all of the ones enumerated above. The processing circuit 620 may further perform data processing functions for inputting, outputting, and processing of data comprising data buffering and device control functions, such as call processing control, user interface control, or the like . Additionally, the communication device 210 comprises a transmitter 630, configured for establishing the emergency call on the subscriber identity 640-1, 640-2, 640-n, determined to have the best signal quality.

The transmitter 630 may be configured for establishing the emergency call on the subscriber identity 640-1, 640-2, according to some embodiments, which is determined to have the best signal quality, irrelevant of whether that subscriber identity 640-1, 640-2, 640-n is the prioritized subscriber identity 640-1, 640-2, 640-n. In further addition, the communication device 210 may comprise a memory 625 according to some embodiments, which may comprise a physical device utilised to store data or programs i.e. sequences of instructions, on a temporary or permanent basis. According to some embodiments, the memory 625 may comprise integrated circuits comprising silicon-based transistors. Further, the memory 625 may be volatile or non-volatile.

The actions 501-503 to be performed in the communication device 210 may be implemented through the one or more processing circuits 620 in the communication device 210, together with computer program code for performing the functions of the actions 501-503. Thus a computer program product, comprising instructions for performing the actions 501-503 in the communication device 210 configured for multiple subscriber identities 640-1, 640-2, 640-n comprising at least a first subscriber identity 640-1 and a second subscriber identity 640-2, configured for making an emergency call according to any of the actions 501-503, when the computer program product is loaded in a processing circuit 620 of the communication device 210.

The computer program product mentioned above may be provided for instance in the form of a data carrier carrying computer program code for performing at least some of the actions 501- 503 according to some embodiments when being loaded into the processing circuit 620. The data carrier may be e.g. a hard disk, a CD ROM disc, a memory stick, an optical storage device, a magnetic storage device or any other appropriate medium such as a disk or tape that may hold machine readable data in a non transitory manner. The computer program product may furthermore be provided as computer program code on a server and downloaded to the communication device 210 remotely, e.g. over an Internet or an intranet connection. The terminology used in the detailed description of the invention as illustrated in the accompanying drawings is not intended to be limiting of the described method 500 and communication device 210, which instead are limited by the enclosed claims.

As used herein, the term "and/or" comprises any and all combinations of one or more of the associated listed items. In addition, the singular forms "a", "an" and "the" are to be interpreted as "at least one", thus also comprising a plurality, unless expressly stated otherwise. It will be further understood that the terms "includes", "comprises", "including" and/or "comprising", specifies the presence of stated features, actions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, actions, integers, steps, operations, elements, components, and/or groups thereof .

Claims

1. A method (500) in a communication device (210) configured for multiple subscriber identities (640-1, 640-2, 640-n) , comprising at least a first subscriber identity (640-1) and a second subscriber identity (640-2), for making an emergency call, comprising: receiving (501) a user input value, indicating that an emergency call is desired; determining (502) the subscriber identity (640-1, 640-2, 640-n) having the cell with the best signal quality; and establishing (503) the emergency call on the subscriber identity (640-1, 640-2, 640-n) determined (502) to have the cell with the best signal quality.

2. The method (500) according to claim 1, wherein the best signal quality is determined (502) based on: received signal quality, received signal strength, signal-to-noise ratio, Received Signal Code Power, ratio of received energy per bit to the interference "Ec/Io", probability for dropped call, Bit Error Rate "BER" .

3. The method (500) according to claim 1, wherein the best signal quality is determined (502) by continuously monitoring the signal quality on each respective subscriber identity (640-1, 640-2, 640-n) .

4. The method (500) according to claim 1, wherein the first subscriber identity (640-1) and the second subscriber identity (640-2) comprises any of a Subscriber Identification Module "SIM" card, a Universal Integrated Circuit Card "UICC", a Universal Subscriber Identity Module "USIM", an Internet protocol multimedia Services Identity Module "I SIM", a Removable User Identity Module "R-UIM", a CDMA Subscriber Identity Module "CSIM", a Willcom-SIM "W-SIM" and/or a Voice over the Internet Protocol "VoIP" subscription.

5. The method (500) according to claim 1, wherein the communication device (210) comprising at least one first subscriber identity (640-1) and one second subscriber identity (640-2) is configured for communication on any technology of: Global System for Mobile Communications "GSM", Enhanced Data Rates for GSM Evolution "EDGE", Universal Mobile Telecommunications System "UMTS", Code Division Access "CDMA", "CDMA 2000", Time Division Synchronous CDMA "TD-SCDMA", Long Term Evolution "LTE"; Wireless Fidelity "Wi-Fi", as defined by any of Institute of Electrical and Electronics Engineers "IEEE" standards 802.11 a, b, g and/or n and/or the Internet Protocol "IP".

6. The method (500) according to claim 1, wherein the best signal quality is determined (502) by using any existing cell selection algorithm for modems.

7. The method (500) according to claim 1, wherein the emergency call is established (503) on the subscriber identity (640-1, 640-2, 640-n) that is determined (502) to have the cell with the best signal quality, irrelevant of whether that subscriber identity (640-1, 640-2, 640-n) is the prioritized subscriber identity (640-1, 640-2, 640-n) .

8. A communication device (210) configured for multiple subscriber identities (640-1, 640-2, 640-n) comprising at least a first subscriber identity (640-1) and a second subscriber identity (640-2), configured for making an emergency call, comprising: a user interface (605), configured for receiving a user input value, indicating that an emergency call is desired; a processing circuit (620) configured for determining the subscriber identity (640-1, 640-2, 640-n) having the cell with the best signal quality; and a transmitter (630), configured for establishing the emergency call on the subscriber identity (640-1, 640-2, 640- n) determined to have the cell with the best signal quality.

9. The communication device (210) according to claim 8, wherein the best signal quality is determined based on: received signal quality, received signal strength, signal-to- noise ratio, Received Signal Code Power, ratio of received energy per bit to the interference "Ec/Io", probability for dropped call, Bit Error Rate "BER" .

10. The communication device (210) according to claim 8, wherein the best signal quality is determined (502) by continuously monitoring the signal quality on each respective subscriber identity (640-1, 640-2, 640-n) .

11. The communication device (210) according to claim 8, wherein the first subscriber identity (640-1) and the second subscriber identity (640-2) comprises any of a Subscriber Identification Module "SIM" card, a Universal Integrated Circuit Card "UICC", a Universal Subscriber Identity Module "USIM", an Internet protocol multimedia Services Identity Module "ISIM", a Removable User Identity Module "R-UIM", a CDMA Subscriber Identity Module "CSIM", a Willcom-SIM "W-SIM" and/or a Voice over the Internet Protocol "VoIP" subscription.

12. The communication device (210) according to claim 8, wherein the communication device (210) comprising at least one first subscriber identity (640-1) and one second subscriber identity (640-2) is configured for communication on any technology of: Global System for Mobile Communications "GSM", Enhanced Data Rates for GSM Evolution "EDGE", Universal Mobile Telecommunications System "UMTS", Code Division Access "CDMA", "CDMA 2000", Time Division Synchronous CDMA "TD-SCDMA", Long Term Evolution "LTE"; Wireless Fidelity "Wi-Fi", as defined by any of Institute of Electrical and Electronics Engineers "IEEE" standards 802.11 a, b, g and/or n and/or the Internet Protocol "IP".

13. The communication device (210) according to claim 8, wherein the best signal quality is determined by using any existing cell selection algorithm for modems.

14. The communication device (210) according to claim 8, wherein the emergency call is established (503) on the subscriber identity (640-1, 640-2, 640-n) that is determined (502) to have the cell with the best signal quality, irrelevant of whether that subscriber identity (640-1, 640-2, 640-n) is the prioritized subscriber identity (640-1, 640-2, 640-n) .

15. Computer program product in a communication device (210) according to any of claims 8-14, configured for multiple subscriber identities (640-1, 640-2, 640-n) comprising at least a first subscriber identity (640-1) and a second subscriber identity (640-2), configured for performing the method (500) for making an emergency call according to any of the claims 1-7, when the computer program product is loaded in a processing circuit (520) of the communication device (210) .