WO2013172680A1

WO2013172680A1 - A method and apparatus for providing support for the execution of emergency calls in a wireless communications system

Info

Publication number: WO2013172680A1
Application number: PCT/KR2013/004373
Authority: WO
Inventors: Ricky Kaura
Original assignee: Samsung Electronics Co., Ltd.
Priority date: 2012-05-18
Filing date: 2013-05-16
Publication date: 2013-11-21

Abstract

A method of providing support for the execution of emergency calls in a wireless communications system. The system comprises user equipment, UE, and a network node, and the cellular wireless communication system supports existing emergency service categories associated with emergency numbers. The method comprises transmitting from the UE to the network node an indication if the UE supports new emergency service categories. The network node determines if the UE supports new emergency service categories. If the network node determines that the UE does support new emergency service categories, the method further comprises determining at the network node to transmit an existing emergency number list, to the UE comprising at least one emergency number and zero, one or more associated existing emergency service categories if no emergency number to be transmitted to the UE has an associated new emergency service category. Alternatively the method further comprises determining at the network node to transmit an alternative emergency number list to the UE and to not transmit an existing emergency number list, the alternative emergency number list comprising at least one emergency number associated with at least one new emergency service category if the network node stores at least one emergency number having an associated new emergency service category. If the network node determines that the UE does not support new emergency service categories the method further comprises determining at the network node to transmit an existing emergency list to the UE comprising at least one emergency number and zero, one or more associated existing emergency service categories.

Description

A METHOD AND APPARATUS FOR PROVIDING SUPPORT FOR THE EXECUTION OF EMERGENCY CALLS IN A WIRELESS COMMUNICATIONS SYSTEM

The present invention relates to a method and apparatus for executing emergency calls. Particular embodiments of the invention are implemented in a 3GPP compliant cellular wireless communications system comprising user equipment, UE, and network equipment. Specifically, embodiments of the present invention address issues with emergency service categories defined by certain 3GPP standards, including difficulties extending the current emergency service categories to cover additional types of emergency calls and emergency numbers.

The 3rd Generation Partnership Project (3GPP) designs, specifies and standardises technologies for cellular (mobile) wireless communications systems. Specifically 3GPP produces a series of technical reports (TR) and technical specifications (TS) that define 3GPP technologies. The focus of 3GPP is currently the specification of standards beyond the 3rd Generation (3G) of cellular systems. The first set of specifications for Long Term Evolution (LTE) and the Evolved Packet Core (EPC) specifications, commonly referred to as 4G standards, have been released as 3GPP Release 10, with work progressing towards 3GPP Release 11.

3GPP TS 22.101, v12.0. (2012-03) “3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Service Aspects; Service Principles (Release 12)” available from www.3GPP.org is a specification that provides general service principles applicable to circuit switch (CS) domain and packet switch (PS) domain cellular wireless communications systems and an IP multimedia subsystem (IMS) core network (CN). Amongst other service principles, 3GPP TS 22.101 provides a general description of emergency call support in a 3GPP compliant CS or PS wireless communications system. By “emergency call” it is meant a call placed by a user to access an emergency service, for instance the police, fire brigade or ambulance. The network equipment is required to connect the emergency call to an emergency service call centre (referred to herein as a Public Safety Answering Point, PSAP). In particular, section 10 of 3GPP TS 22.101 specifies that for a 3GPP compliant cellular wireless communications system it shall be possible to establish an emergency speech call or Global Text Telephony, GTT, call, subject to national requirements (both referred to herein as an emergency call). Emergency calls must be routed to the emergency services in accordance with national regulations for where the UE is located. The UE comprises mobile equipment (ME) in combination with a subscriber identity module (SIM) or universal SIM (USIM). In the present patent specification when referring to interactions with the network the term UE will be used. When referring to the functionality of the mobile device on its own the term ME will be used. This routing may be based upon one or more default emergency call numbers stored in the UE. An emergency call may be initiated by a user by manually entering a predetermined emergency call number, or via another mechanism such as a menu, a dedicated button or other automated system in order to prevent misconnection when the UE is not located in the home network.

Section 10 of 3GPP TS 22.101 specifies a mechanism for the UE to automatically provide an emergency service category associated with the emergency call number selected by the user. In the present patent specification, the term “existing emergency service category” will be used when referring to an emergency service category defined in section 10 of 3GPP TS 22.101 in order to distinguish the new emergency service categories used in the present invention. The existing emergency service category may, for instance, be one or more of "police", "fire brigade" or "ambulance". Each existing emergency service category is provided to the network in an emergency call setup message (in place of the UE supplying the selected emergency number digits to the network) allowing the network to correctly connect the emergency call to an appropriate PSAP. Supplying existing emergency service categories to the network reduces the risk of misconnection, which may occur if the emergency call number itself were provided to the network and the UE has roamed to outside of the home network, in particular if the UE has roamed to a network in another country where different emergency numbers are used. However, section 10 of 3GPP TS 22.101 defines a limited number of emergency service categories and is not readily extensible as and when further types of emergency calls emerge.

3G radio technologies specified by 3GPP such as UMTS are based upon CS and PS technologies. Current 2G/3G systems implement 3GPP TS 22.101. The SAE/LTE system that is now currently being designed, specified and standardised by 3GPP is a PS only system. PS-only systems also implement TS 22.101. This means there is no CS domain and voice calls in an SAE/LTE system are conducted solely through the PS domain.

It is anticipated that such PS systems will implement support for further emergency services categories. However, this not as of yet any proposal for how a UE, which can operate in both the CS and the PS domains, may be configured for and receive new emergency categories in a backwards compatible manner.

It is an aim of embodiments of the present invention to obviate or mitigate one or more of the problems associated with the prior art, whether identified herein or elsewhere. In particular, it is an aim of embodiments of the present invention to address issues of backwards compatibility when configuring a UE to receive and use new emergency service categories. Advantageously, this allows the network to route emergency calls to an appropriate PSAP, which may be more specific to the UE user’s emergency situation. Particular embodiments of the present invention address the logic within a UE for deciding what information elements should be delivered to the network. Further embodiments of the present invention address the logic in the network for deciding what information elements should be delivered to a UE.

According to a first aspect of the present invention there is provided a method of providing support for the execution of emergency calls in a cellular wireless communications system comprising user equipment, UE, and a network node, where the cellular wireless communication system supports existing emergency service categories associated with emergency numbers, the method comprising: transmitting from the UE to the network node an indication if the UE supports new emergency service categories; and determining at the network node if the UE supports new emergency service categories; wherein if the network node determines that the UE does support new emergency service categories the method further comprises: determining at the network node to transmit an existing emergency number list, to the UE comprising at least one emergency number and zero, one or more associated existing emergency service categories if no emergency number to be transmitted to the UE has an associated new emergency service category; and determining at the network node to transmit an alternative emergency number list to the UE and to not transmit an existing emergency number list, the alternative emergency number list comprising at least one emergency number associated with at least one new emergency service category if the network node stores at least one emergency number having an associated new emergency service category; and wherein if the network node determines that the UE does not support new emergency service categories the method further comprises: determining at the network node to transmit an existing emergency list to the UE comprising at least one emergency number and zero, one or more associated existing emergency service categories.

The alternative emergency number list may include at least one emergency number, each emergency number being associated with zero, one or more existing emergency service categories and further associated with zero, one or more new emergency service categories.

Each existing emergency service category may comprise an emergency service category as specified in section 10 of 3GPP TS 22.101 and each new emergency service category may comprise an emergency service category corresponding to a sub-service described in IETF RFC 5031 and which is not an emergency service category as specified in 3GPP TS 22.101.

Transmitting from the UE to the network node an indication if the UE supports new emergency service categories may comprise including a new-emergency-service-category-supported indication within an EPS/GPRS Attach message or a Tracking Area Update/Routing Area Update or a Location Update message transmitted from the UE to the network if the UE supports the use and storage of an alternative emergency number list IE.

The method may further comprise determining at the UE whether a telephone number dialled by a user comprises an emergency number, and if so transmitting an emergency request to the network node, wherein if the UE supports new emergency service categories the method further comprises determining whether the emergency number is associated with one or more existing emergency service category and determining whether the emergency number is associated one or more new emergency service category, and if so incorporating at least one associated existing emergency service category or new emergency service category within the emergency request sent to the network node.

If the emergency request is sent to the network node in the CS domain an emergency setup message may be transmitted to the network node including zero, one or more existing emergency service category information elements, IEs, and zero, one or more new emergency service category IEs and if the emergency request is sent to the network node in the PS domain an emergency INVITE message may be transmitted to the network node including an emergency service URN and zero or one sub-service type.

If the UE determines that the emergency number dialled by the user is associated with more than one existing emergency service category or new emergency service category, and if the UE further determines that the selected domain for connecting the emergency call to the network cannot transmit more than one emergency service category, the method may further comprise the UE further providing the ability for the user to select a single existing emergency service category or new emergency service category from the associated emergency service categories, and the UE transmitting the selected emergency service category to the network node.

Transmitting from the UE to the network node an indication if the UE supports new emergency service categories may comprise determining if the UE is connected to the network in UTRAN and if so including an indication that the new emergency service categories are supported to the network node within in a location update message.

Transmitting from the UE to the network node an indication if the UE supports new emergency service categories may comprise determining if the UE is connected to the network in GERAN and if so the method further comprises not including an indication whether the new emergency service categories are supported to the network node within a location update message.

The method may further comprise storing within a SIM / USIM card within the UE at least one emergency number associated with zero, one or more existing emergency service category and zero, one or more new emergency service categories.

The method may further comprise configuring the SIM / USIM card with the associated zero, one or more existing emergency service categories and zero, one or more new emergency service categories within an existing emergency call code elementary file EFECC extended to specify the zero, one or more new emergency service category or within an extended emergency call code elementary file EFXECC.

The method may further comprise transmitting an emergency request to the network node and incorporating each associated existing emergency service category and each associated new emergency service category within the emergency request sent over the to the network node by comparing an emergency number dialled by a user with the information stored in the EFECC or EFXECC.

The existing emergency number list IE may be as specified in section 10.5.4.33 of 3GPP TS 24.008 and the alternative emergency number list IE is as specified in section 10.5.4.33 of 3GPP TS 24.008 and further comprising at least one alternative emergency service category value octet associated with each emergency number encoding associated new emergency service categories for each emergency number.

The alternative emergency number list IE may be as specified in section 10.5.4.33 of 3GPP TS 24.008 and wherein at least one of bits 6 to 8 of the emergency service category value octet associated with each emergency number encodes an associated new emergency service category for each emergency number.

According to a second aspect of the present invention there is provided a method of providing support for the execution of emergency calls within a UE in a cellular wireless communications system which further comprises a network node, the cellular wireless communication system supporting existing emergency service categories associated with emergency numbers, the method comprising: transmitting from the UE to the network node an indication if the UE supports new emergency service categories arranged to allow the network node to determine if the UE supports new emergency service categories; receiving at the UE an existing emergency number list comprising at least one emergency number and zero, one or more associated existing emergency service categories if no emergency number stored at the network node to be transmitted to the UE has an associated new emergency service category or if the UE does not indicate to the network node that it supports new emergency service categories; and receiving at the UE an alternative emergency number list and not receiving at the UE an existing emergency number list, the alternative emergency number list comprising at least one emergency number associated with at least one new emergency service category if the network node stores at least one emergency number to be transmitted to the UE having an associated new emergency service category and the UE indicates to the network node that it supports new emergency service categories.

According to a third aspect of the present invention there is provided a method of providing support for the execution of emergency calls within a network node in a cellular wireless communications system which further comprises user equipment, UE, the cellular wireless communication system supporting existing emergency service categories associated with emergency numbers, the method comprising: receiving at the network node from the UE an indication if the UE supports new emergency service categories; and determining at the network node if the UE supports new emergency service categories; wherein if the network node determines that the UE does support new emergency service categories the method further comprises: determining at the network node to transmit an existing emergency number list, to the UE comprising at least one emergency number and zero, one or more associated existing emergency service categories if no emergency number to be transmitted to the UE has an associated new emergency service category; and determining at the network node to transmit an alternative emergency number list to the UE and to not transmit an existing emergency number list, the alternative emergency number list comprising at least one emergency number associated with at least one new emergency service category if the network node stores at least one emergency number having an associated new emergency service category; and wherein if the network node determines that the UE does not support new emergency service categories the method further comprises: determining at the network node to transmit an existing emergency list to the UE comprising at least one emergency number and zero, one or more associated existing emergency service categories.

According to a fourth aspect of the present invention there is provided a cellular wireless communications system arranged to provide support for the execution of emergency calls, the cellular wireless communication system supporting existing emergency service categories associated with emergency numbers, the cellular wireless communications system comprising: UE; and a network node; wherein the UE is arranged to transmit to the network node an indication if the UE supports new emergency service categories and to receive from the network node an existing emergency number list or an alternative emergency number list; wherein the network node is arranged to determine if the UE supports new emergency service categories; wherein if the network node determines that the UE does support new emergency service categories the network node is further arranged to determine to transmit an existing emergency number list, to the UE comprising at least one emergency number and zero, one or more associated existing emergency service categories if no emergency number to be transmitted to the UE has an associated new emergency service category, and to determine to transmit an alternative emergency number list to the UE and to not transmit an existing emergency number list, the alternative emergency number list comprising at least one emergency number associated with at least one new emergency service category if the network node stores at least one emergency number having an associated new emergency service category; and wherein if the network node determines that the UE does not support new emergency service categories the network node is further arranged to determine to transmit an existing emergency list to the UE comprising at least one emergency number and zero, one or more associated existing emergency service categories.

According to a fifth aspect of the present invention there is provided a UE within a cellular wireless communications system which further comprises a network node, the UE being arranged to provide support for the execution of emergency calls, the cellular wireless communication system supporting existing emergency service categories associated with emergency numbers: wherein the UE is arranged to transmit to the network node an indication if the UE supports new emergency service categories to allow the network node to determine if the UE supports new emergency service categories and to receive from the network node an existing emergency number list or an alternative emergency number list; wherein if the UE does support new emergency service categories the UE is arranged to receive an existing emergency number list from the network node comprising at least one emergency number and zero, one or more associated existing emergency service categories if no emergency number stored in the network node to be transmitted to the UE has an associated new emergency service category, and the UE is arranged to receive an alternative emergency number list from the network node and to not receive an existing emergency number list, the alternative emergency number list comprising at least one emergency number associated with at least one new emergency service category if the network node stores at least one emergency number having an associated new emergency service category; and wherein if the UE does not support new emergency service categories the UE is arranged to receive an existing emergency list from the network node comprising at least one emergency number and zero, one or more associated existing emergency service categories.

According to a sixth aspect of the present invention there is provided a network node within a cellular wireless communications system which further comprises a UE, the network node being arranged to provide support for the execution of emergency calls, the cellular wireless communication system supporting existing emergency service categories associated with emergency numbers: wherein the network node is arranged to receive from the UE an indication if the UE supports new emergency service categories; wherein the network node is arranged to determine if the UE supports new emergency service categories; wherein if the network node determines that the UE does support new emergency service categories the network node is further arranged to determine to transmit an existing emergency number list, to the UE comprising at least one emergency number and zero, one or more associated existing emergency service categories if no emergency number to be transmitted to the UE has an associated new emergency service category, and to determine to transmit an alternative emergency number list to the UE and to not transmit an existing emergency number list, the alternative emergency number list comprising at least one emergency number associated with at least one new emergency service category if the network node stores at least one emergency number having an associated new emergency service category; and wherein if the network node determines that the UE does not support new emergency service categories the network node is further arranged to determine to transmit an existing emergency list to the UE comprising at least one emergency number and zero, one or more associated existing emergency service categories.

According to a seventh aspect of the present invention there is provided a computer program product comprising a non-transitory computer-readable storage medium having computer readable instructions stored thereon, the computer readable instructions being executable by a computerized device to cause the computerized device to perform the method of processing state information in a radio access network described above.

According to an eighth aspect of the present invention there is provided a computer program product comprising a non-transitory computer-readable storage medium having computer readable instructions stored thereon, the computer readable instructions being executable by a computerized device to cause the computerized device to perform the method of processing state information in a radio access network described above.

According to a nineth aspect of the present invention there is provided a computer program product comprising a non-transitory computer-readable storage medium having computer readable instructions stored thereon, the computer readable instructions being executable by a computerized device to cause the computerized device to perform the method of processing state information in a radio access network described above.

Another aspect of the invention provides a computer program comprising instructions arranged, when executed, to implement a method and/or apparatus in accordance with any one of the above-described aspects. A further aspect provides machine-readable storage storing such a program.

Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which:

Figure 1 illustrates an existing emergency category Information Element (IE) as defined by section 10.5.4.33 of 3GPP TS 24.008.

Figure 2 illustrates an existing emergency number list IE as defined by section 10.5.3.13 of 3GPP TS 24.008.

Figure 3 illustrates an alternative emergency number list IE according to one example embodiment only of the present invention.

Figure 4 is a sequence flow diagram illustrating a first scenario for actions performed at the UE and a Mobility Management Entity (MME) / Serving GPRS (General Packet Radio System) Support Node (SGSN) in accordance with an embodiment of the present invention.

Figure 5 is a sequence flow diagram illustrating a second scenario for actions performed at the UE and a MME / SGSN in accordance with an embodiment of the present invention.

Figure 6 is a sequence flow diagram illustrating a third scenario for actions performed at the UE and a MME / SGSN in accordance with an embodiment of the present invention.

Figure 7 is a sequence flow diagram illustrating a fourth scenario for actions performed at the UE and a MME / SGSN in accordance with an embodiment of the present invention.

Figure 8 illustrates the encoding of a first IE according to an embodiment of the present invention in an alternative emergency number list according to Figure 3.

Figure 9 illustrates the encoding of a second IE according to an embodiment of the present invention in an alternative emergency number list according to Figure 3.

Figure 10 is a sequence flow diagram illustrating a first scenario for actions performed at the UE in UTRAN and a Mobile Switching Centre (MSC) during a location update request and response in accordance with an embodiment of the present invention.

Figure 11 is a sequence flow diagram illustrating a second scenario for actions performed at the UE in GERAN and a MSC during a location update request and response in accordance with an embodiment of the present invention.

Figure 12 is a sequence flow diagram illustrating actions performed at the UE and a MSC during an emergency setup in accordance with an embodiment of the present invention.

Figure 13 illustrates an emergency setup message according to an embodiment of the present invention.

Figure 14 illustrates a new emergency service category Information Element (IE) according to an embodiment of the present invention.

Figure 15 illustrates an extended emergency call code elementary file (EFXECC) according to an embodiment of the present invention (a non-illustrated embodiment of the invention being to extend an existing emergency call code EFECC).

Figure 16 is a flow chart illustrating logic performed at the UE at switch on in accordance with an embodiment of the present invention;

Figure 17 is a flow chart illustrating logic performed at the MME / SGSN / MSC on attach / update procedures in accordance with an embodiment of the present invention.

Figure 18 is a flow chart illustrating logic performed at the UE on making a CS (Universal Terrestrial Radio Access Network: UTRAN) emergency call in accordance with an embodiment of the present invention.

Figure 19 illustrates a wireless communication system in accordance with an embodiment of the present invention.

As noted above in the background to the invention section, embodiments of the present invention aim to provide a UE and a network in which it is possible to seamlessly move from supporting existing emergency service categories used in CS networks to supporting more extensive new emergency service categories to be used when emergency calls are supported over PS networks. Advantageously this allows the UE and the network to support new emergency service categories providing the ability to accurately connect emergency service calls to more narrowly focussed PSAPs. First, however, existing standards defined by 3GPP for implementing emergency calls will be described in greater detail.

3GPP TS 22.101 section 10 gives a general description of emergency call support which was written to be focussed on the currently implemented CS 2G/3G cellular wireless communications networks. When a user dials one of a closely defined group of emergency numbers (for instance 112 in many European countries and 911 in the US) 3GPP TS 22.101 requires that the dialled number be recognised as an emergency number within the UE. This means that the emergency number has to be identified. There are four ways in which a UE may be provided with emergency numbers so that the UE can recognise those emergency numbers when selected or entered by a user. Firstly, a small group of emergency numbers are always available on the ME. Secondly, the SIM / USIM may be preconfigured with additional emergency numbers. Thirdly, some emergency numbers are made available when no SIM or USIM is present in the ME. Fourthly, additional emergency numbers downloaded from the serving network are made available when the SIM / USIM is present in the ME.

TS 22.101 section 10.1.1 specifies the following minimum group of emergency numbers:

a) 112 and 911 shall always be available. These numbers shall be stored on the ME.

b) Any emergency call number stored on a SIM/USIM when the SIM/USIM is present.

c) 000, 08, 110, 999, 118 and 119 when a SIM/USIM is not present. These numbers shall be stored on the ME. [Part (c) addresses a different issue to part (a) because these numbers are made available when the SIM/USIM is not present. The numbers 112 and 911 are always available independent of the presence of the SIM/USIM because they are universal emergency numbers. The emergency numbers in part (c) are known to be used in certain countries.]

d) Additional emergency call numbers that may have been downloaded by the serving network when the SIM/USIM is present. [Part (b) includes numbers that are stored on the SIM card. Part (d) adds additional numbers that the network can download when the SIM/USIM is present. Currently, for limited service (no USIM/SIM) emergency calls, the network is not allowed to download further emergency numbers (the ME forms an emergency attach to the network).]

When a telephone number dialled, entered or selected by a user is identified by the UE as an emergency number (matching to an emergency number according to (a)-(d) as applicable), then the UE is arranged to send an emergency setup message to the network. 3GPP TS 24.008 v11.2.1 (2012-03) "3rd Generation Partnership Project; Technical Specification Group Core Network and Terminals; Mobile radio interference Layer 3 specification; Core network protocols; Stage 3 (Release 11" available from www.3GPP.org describes the emergency setup Non-Access Stratum (NAS) message. The conventional emergency setup procedure will not be described in greater detail here, except for the following more detailed discussion of existing emergency call number service categories (which may also be referred to as emergency service categories), which are included where available in an emergency call setup message.

As noted above, according to 3GPP TS 22.101 for CS and PS domain emergency calls, emergency calls are configured and stored on the USIM/SIM or ME or downloaded from the network along with an associated service category. Upon the UE identifying that a telephone number dialled, entered or selected by a user is an emergency number, the UE determines any associated existing emergency service category and associated existing emergency service categories are included in the emergency setup message transmitted to the network. That is, section 10.1 of TS 22.101 specifies that each emergency number stored in the ME or the SIM / USIM may be mapped or tied to zero, one or more than one existing emergency service category. The association between the emergency numbers and the existing emergency service categories is typically provided by the home environment operator either when supplying the ME, SIM or USIM or when downloading emergency numbers to the UE. The Service Category allows the mobile services switching center, MSC, to route the call to a service-specific public safety answering point, PSAP, rather than a default PSAP. 3GPP TS 22.101 specifies a limited number of existing emergency service categories in section 10.1:

Police

Ambulance

Fire Brigade

Marine Guard

Mountain Rescue

Manually Initiated eCall (MIeC)

Automatically Initiated eCall (AIeC)

[Spare]

The existing emergency service categories relating to eCalls are not directly relevant to the present invention which is concerned with the processing of emergency numbers selected by a user. A brief description of eCalls can be found at:

http://ec.europa.eu/information_society/activities/esafety/ecall/index_en.htm

Section 10.1 of 3GPP TS 22.101 provides an example of mapping emergency numbers to one or more existing emergency service categories:

19 Police (Albania)

100 Police and Fire Brigade (Greek cities)

100 Ambulance and Fire Brigade (Belgium)

112 Police and Ambulance (Italy)

112 General emergency call, all categories (Sweden)

115 Fire Brigade (Italy)

144 Ambulance (Austria)

As noted above, 3GPP TS 24.008 describes emergency setup NAS messages transmitted by the UE upon a user selecting an emergency number, including the current encoding of an emergency service category. Specifically, section 10.5.4.33 of 3GPP TS 24.008 specifies that the service category of an emergency number is encoded as a service category information element as illustrated in Figure 10.5.118d of 3GPP TS 24.008 and as illustrated in Figure 1 of the present patent specification. For clarity, Service Category as an information element (IE) is defined for inclusion only in Emergency Set-up messages. The service categories for the existing emergency number list IE described below refer to only bits 1 to 5 of the Service Category IE value included in emergency number list IEs (to be described below). Consequently,

bits

6 and 7 for eCall are not relevant for the downloaded list, but are relevant for Emergency Setup messages. The service category is a type 4 information element, IE, as defined in 3GPP TS 24.007 with a minimum length of 3 octets. The first octet identifies the IE as a service category IE. The second octet indicates the length of the IE. The content of the existing emergency service category value (octet 3) determines which (if any) existing emergency service categories are associated with the emergency number selected by the user. Specifically, each bit of octet 3 is mapped to a respective service category (defined by table 10.5.135d of 3GPP TS 24.008) as follows:

Bit 1 Police

Bit 2 Ambulance

Bit 3 Fire Brigade

Bit 4 Marine Guard

Bit 5 Mountain Rescue

Bit 6 manually initiated eCall

Bit 7 automatically initiated eCall

Bit 8 is spare and set to "0"

If any bit of octet 3 is set to "1" (except bit 8, which is spare) then the MSC is arranged to interpret this as meaning that the emergency call should be routed to a PSAP corresponding to that existing emergency service category. If more than one bit is set to "1", the MSC is arranged to route the call to a combined PSAP associated with those existing service categories (e.g. ambulance and fire brigade in Japan or ambulance, fire brigade and police in the United Kingdom). If the MSC cannot match the received existing emergency service category or set of categories to any specific PSAP, the MSC is arranged to route the emergency call to an operator defined default PSAP. If no bit in octet 3 is set to "1", the MSC is arranged to route the emergency call to an operator defined default PSAP. For completeness, it is noted that a UE initiating an eCall sets either bit 6 or bit 7 to "1". The network may use the information indicated in bit 6 and bit 7 to route the manually or automatically initiated eCall to an operator defined PSAP.

The existing emergency service categories associated with each identifiable emergency number are stored within the ME or the SIM / USIM within an emergency number list IE specified by section 10.5.3.13 of 3GPP TS 24.008 and illustrated in Figure 10.5.84c of 3GPP TS 24.008, reproduced in the present patent specification as Figure 2. The emergency number list IE specified by 3GPP TS 24.008 is referred to in the present patent specification as an existing emergency number list IE in order to distinguish an alternative emergency number list IE proposed by the present invention. The existing emergency number list IE encodes the existing emergency service categories alongside each emergency number allowing the UE to simply check a selected telephone number against the existing emergency number list to identify an emergency number and the existing emergency service categories to include in the service category IE of Figure 1. The existing emergency number list IE is communicated to the UE from the network. For instance the existing emergency number list IE may be sent back from the MSC within a Location Update Accept message as a result of IMSI-attach or Location Area Updating. Additionally, to support PS emergency calls (described in greater detail below), the existing emergency number list IE is also sent back by the SGSN/MME in the following messages: GPRS Attach Accept, Routing Area Update Accept, EPS Attach Accept and Tracking Area Update Accept.

The existing emergency number list is an IE with a minimum length of 5 octets and a maximum length of 50 octets. Octet 1 of the existing emergency number list IE identifies the IE as an existing emergency number list. Octet 2 encodes the total length of the existing emergency number list IE contents. Octet 3 encodes the length of the first emergency number information including the emergency number digits and the existing emergency service category value. Octet 4 is the existing emergency service category value and encodes the existing emergency service category or categories for the first emergency number as for bits 1 to 5 of octet 3 of the existing emergency service category IE illustrated in figure 1. Bits 6 to 8 are not used and are available in principle for further use. In certain embodiments of the present invention these spare bits may be used to encode new emergency service categories before introducing a new octet specifically for encoding new emergency service categories within an alternative emergency number list IE, as will be described in greater detail below. However, without introducing a new octet only three new emergency service categories could be introduced. Additionally, as described in greater details below, the UE is able to signal to the network that it supports the new emergency service categories and the UE is able to process the spare bits, not simply discard them. There then follows a variable number of octets (5 to (j-1)) encoding the digits of the emergency number. The digit(s) in octet 5 precede the digit(s) in octet 6, with this pattern being repeated for longer emergency numbers. The number digit, which would be entered first, is located in octet 5, bits 1 to 4. If the emergency number contains an odd number of digits, bits 5 to 8 of the last octet of the respective emergency number are filled with an end mark coded as "1111".

There now follows a discussion of conventional PS domain emergency calls as defined and implemented by existing 3GPP standards.

PS emergency calls are IP multimedia subsystem IMS-based and are described in 3GPP TS 23.167 v11.4.0 (2012-03) "3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; IP Multimedia Subsystem (IMS) emergency sessions (Release 11)" and 3GPP TS 24.229 v11.3.0 (2012-03) "3rd Generation Partnership Project; Technical Specification Group Core Network and Terminals; IP multimedia call control protocol based on Session Initiation Protocol and Session Description Protocol (SDP); Stage 3 (Release 11)" both available from www.3GPP.org.

3GPP TS 24.229 for PS emergency calls aligns with 3GPP TS 22.101 for the identification of emergency numbers such that the existing emergency number list IE is used within the UE to store emergency numbers and associated existing emergency service categories, and to identify selected emergency numbers as described above. Section 5.1.6.8.1 of 3GPP TS 24.229 specifies how the associated existing emergency service category is used within IMS signalling to the CN:

The ME shall translate any user indicated emergency number as specified in 3GPP TS 22.101 to an emergency service URN, i.e. a service URN with a top-level service type of "sos" as specified in RFC 5031. An additional sub-service type can be added if information on the type of emergency service is known.

Currently, for emergency calls connected in the PS domain, the same emergency number list IE is used in the UE to identify emergency calls and the emergency service categories, even though in a broader set of sub-service types can be sent by the UE to the network in a PS emergency call. The emergency categories that are specified in 3GPP TS 22.101 are supported by RFC 5031, so for these categories, the UE is able to map the existing emergency service category sent by the network into the appropriate sub-service type when the PS domain is used to connect the emergency call or as normal in the emergency category sent in a CS domain emergency setup message. Embodiments of the present invention extend this capability in the USIM/SIM/ME and network to support the mapping to newer PSAP emergency services.

For IMS emergency calls (after successful IMS emergency registration), the UE sends an "emergency" SIP INVITE message which contains a 'Request-URI' containing an emergency service URN. The emergency service URN is identified with a service type of "sos" as specified in RFC 5031 from the Internet Engineering Task Force (IETF): urn:service:sos. If no further service types are specified, the generic 'sos' service is routed by the network to a default PSAP.

The reference to "additional sub-service type" in section 5.1.6.8.1 of 3GPP TS 24.229 refers to the ability to add further service category information to the sos-urn to provide a more specific service category. Similar to CS emergency calls, this allows the network to target a specific PSAP providing a specific emergency service.

As for CS emergency calls, at the network side (transport level), the emergency number list IE is sent back from the SGSN/MME to the UE in the following messages:

GPRS Attach Accept

Routing Area Update Accept

EPS Attach Accept

Tracking Area Update Accept

The messages shown above are used within the transport layer when the UE registers over the transport layer with the network. The emergency call itself is sent over the PS domain, uses application layer IMS SIP signalling over the PS transport layer signalling. Rather than have separate emergency number lists for use in the CS domain or the PS domain, embodiments of the present invention provide an alternative emergency number list IE to include further categories that can be sent in "ACCEPT" messages for PS attachment/updating and also for CS attachment/updating.

RFC 5031 describes the following sub-service types which can be appended to the "sos-urn":

urn:service:sos.ambulance This service identifier reaches an ambulance service that provides emergency medical assistance and transportation.

urn:service:sos.animal-control Animal control typically enforces laws and ordinances pertaining to animal control and management, investigates cases of animal abuse, educates the community in responsible pet ownership and wildlife care, and provides for the housing and care of homeless animals, among other animal-related services.

urn:service:sos.fire The 'fire' service identifier summons the fire service, also known as the fire brigade or fire department.

urn:service:sos.gas The 'gas' service allows the reporting of natural gas (and other flammable gas) leaks or other natural gas emergencies.

urn:service:sos.marine The 'marine' service refers to maritime search and rescue services such as those offered by the coast guard, lifeboat, or surf lifesavers.

urn:service:sos.mountain The 'mountain' service refers to mountain rescue services (i.e., search and rescue activities that occur in a mountainous environment), although the term is sometimes also used to apply to search and rescue in other wilderness environments.

urn:service:sos.physician The 'physician' emergency service connects the caller to a physician referral service.

urn:service:sos.poison The 'poison' service refers to special information centres set up to inform citizens about how to respond to potential poisoning. These poison control centres maintain a database of poisons and appropriate emergency treatment.

urn:service:sos.police The 'police' service refers to the police department or other law enforcement authorities.

It will be noted that the list of sub-service types includes all of the service categories for CS emergency calls specified in TS 22.101. However, "animal control", "gas", "physician" and "poison" are newly specified by RFC 5031. It will be appreciated that the significance of this is that the current mechanism specified for emergency setup in 3GPP TS 24.008 for CS domain emergency calls can only be used to support a subset of the available sub-service types specified in RFC 5031 which are available in PS domain emergency calls. Specifically, while additional sub-service types are available for signalling to a network in a PS emergency call, there is no mechanism for specifying the additional sub-service types in the existing emergency number list IE which is downloaded to and stored within the UE and used by the UE to identify emergency calls and locate the appropriate service category (CS) or sub-service type (PS). Therefore the statement made in section 5.1.6.8.1 of 3GPP TS 24.229 "An additional sub-service type can be added if information on the type of emergency service is known" cannot be fully realised because there is no ability in the USIM/SIM, ME or in the NAS signalling protocol to tie an emergency number to the following service categories or sub-service types for “Animal control", "Gas", "Physician" and "Poison" and furthermore, using the existing emergency number list IE the SIM/USIM cannot be configured with new emergency service categories. Consequently, for cellular wireless communications systems compliant with current 3GPP standards, in practice support for PS emergency calls is limited to the same available service categories specified in TS 22.101 and TS 24.008 for CS and the full standard in 3GPP TS 24.229 cannot be implemented. In practice, for current 3GPP cellular wireless communications networks operators are not able to route calls to newer PSAPs that provide a more targeted emergency service.

It will be appreciated that the inability to fully implement the addition sub-service types for PS emergency calls is a significant limitation to the potential benefits of routing emergency calls in the PS domain, and limits the ability to develop more specific PSAPs. However, it will be further appreciated that even if it were possible to fully implement the addition sub-service types for PS emergency calls, it is undesirable for it to only be possible to route emergency calls to certain PSAPs in the event that the UE connects the emergency call in the PS domain and not in the CS domain. The implementation of emergency call support is a regulatory requirement in most countries as the provision of emergency services to the public is a regulated activity in most countries. For instance PS (Voice over IP, VoIP) requirements for emergency calls are described by National Emergency Number Association, NENA, in North America. There are strict rules for routing emergency calls. It is possible that there could be delays if the emergency call gets routed to a default PSAP, and then needs to be routed onwards. This exposes network operators to potential lawsuits. In Europe IR.92/IR.58 (specified by the GSM association, GSMA) specifies a profile for the provision of Voice over LTE/Voice over High Speed Packet Access, HSPA. Network operators sign up and are committed to support this profile which is based upon the 3GPP specifications. If emergency calls do not operate as expected this would reflect negatively on the work of 3GPP

Embodiments of the present invention addressing at least some of the above identified problems will now be described. The solution to the problem of inability to fully implement TS 24.229 proposed by the present invention does not require the standardisation of a new mechanism for allowing the USIM/SIM/ME be configured for and to receive new emergency categories. This provides the significant advantage of backwards compatibility for UEs which are unable to implement the present invention, and which may continue to receive, store and use existing emergency number list IEs as described above using the emergency service categories specified in TS 22.101. Embodiments of the present invention described below address the logic required in a UE for deciding what information elements should be delivered to a network and the logic in a network for deciding what information elements should be delivered to a UE.

According to a first embodiment of the present invention, the USIM / SIM can be optionally configured with a new elementary file, EF, which allows the specification of the emergency call codes (emergency service categories when the UE connects to the network in the CS domain and emergency sub-service types when the UE connects to the network in the PS domain, referred to hereinafter as emergency service categories for simplicity). As will be described below, alternatively the existing EF file may be modified. The emergency call codes (emergency service categories) in the new EF allow the specification of new emergency service categories, in an open ended, flexible manner. The specification of new emergency service categories includes, but is not limited to, the full list of emergency sub-service types specified in RFC 5031. An EF file is a file within the USIM/SIM that can be configured by the operator. EF files contain information required by the USIM/SIM to operate. One of the EF files, the emergency call code elementary file EFECC contains the configured emergency numbers by the Home PLMN Operator and associated existing service categories.

In accordance with an embodiment of the present invention an alternative emergency number list IE illustrated in Figure 3 is created and used. The alternative emergency number list IE extends and if used replaces the existing emergency number list specified in 3GPP TS 24.008 and contains the encoding of emergency numbers that make use of the new emergency service categories. As will be described in greater detail below, to ensure backwards compatibility with UEs not able to make use of the alternative emergency number list IE, or where the network stores only emergency numbers not mapped to a new emergency service category defined in RFC 5031, the network sends either the existing emergency number list IE or the alternative emergency number list IE. In certain embodiments there is no need to send both. Specifically the network sends the appropriate emergency number list IE as follows:

- If the network is aware that the UE can only support the existing emergency number list then the network only sends the existing emergency number list IE.

- If the network only has emergency numbers that have an existing emergency service category (or combination of existing emergency service categories), then the network only sends the existing emergency number list IE.

- If the network only has emergency numbers that have the new emergency service categories (or combination of new emergency service categories) then the network only sends the alternative emergency number list IE.

- If the network has emergency numbers that only have the existing service category and emergency numbers that only have the new service category, then the network sends only the alternative emergency number list IE.

- If the network has emergency numbers that map to both an existing emergency service category and a new emergency service category, then the network sends only the alternative emergency number list IE.

Referring to Figure 3, it will be appreciated that the alternative emergency number list IE is substantially the same as the existing emergency number list IE of Figure 2, except for the addition of a further octet for each emergency number (for instance octet 4a for the first emergency number). Octet 4a is the new emergency service category value and encodes the new emergency service category or categories for the first emergency number. Each emergency number may be encoded with zero, one or more service categories from either or both of the existing emergency service categories in octet 4 or the new emergency service categories in octet 4a. In certain embodiments of the present invention, as well, or instead of encoding an additional octet 4a, the spare bits of the existing emergency service category octet 4 may be used first. However, to fully implement all of the sub-service types set out in RFC 5031 it is necessary to use at least one bit of an additional octet. Additionally, the spare bits of the existing emergency service category value octet may be reserved for other, future purposes. It will be appreciated that the encoding of the new emergency service category may vary, and indeed may be encoded by additional octets as required. In one particular embodiment the new emergency service category value is encoded with bits 1 to 4 derived from usage of the sub-service type in RFC 5031 as follows:

Bit 1 Animal Control

Bit 2 Gas

Bit 3 Physician

Bit 4 Poison

Bit 5 is spare and set to "0"

Bit 6 is spare and set to "0"

Bit 7 is spare and set to "0"

Bit 8 is spare and set to "0"

When the UE connects to the network in the PS domain the alternative emergency number list IE is sent, as required, to the UE included in the following messages:

- GPRS Attach Accept

- Routing Area Update Accept

- EPS Attach Accept

- Tracking Area Update Accept

As discussed above, the UE is arranged to identify selected numbers as emergency numbers by reference to the existing emergency number list IE or the alternative emergency number list IE as appropriate and identify the or each new or existing emergency service category associated with the emergency number. It is noted that as currently specified in TS 24.229 it seems that there is no way in PS emergency calls to allow messages sent from the UE to the network to include more than one sub-service type, that is it seems not possible to route to a "X-and-Y" PSAP. This is in contrast to the way CS emergency calls are supported. In certain embodiments of the invention, when the domain selection rules choose the PS domain to connect an emergency call then when the user dialled a number the UE implementation displays a pop-up a window allowing the user to choose the correct new emergency service category to be sent to the network.

To allow for synergy of the solution irrespective of the type of domain used to connect an emergency call is attempted on, in certain embodiments of the invention the alternative emergency number list is also included in Location Updating Accept messages as a result of IMSI-attach or Location Area Updating when the UE is connected to the network in the CS domain. However, due to certain limitations of GSM networks, in certain embodiments of the invention when the UE is connected to a GSM network it may not be possible to implement the alternative emergency number list IE, and so by default the networks in accordance with certain embodiments of the invention default to supplying an existing emergency number list IE to the UE, as will be now be described.

In order for the network to know that it is possible for the UE to receive and store an alternative emergency number list IE the UE, in certain embodiments, must first tell the network that it can support receipt of the alternative emergency number list. A "feature support bit" indicating the UE's compatibility with the alternative emergency number list IE is included in the following messages sent by the UE to the network:

- GPRS Attach

- Routing Area Update

- EPS Attach

- Tracking Area Update

The "feature support bit" could be included in Location Updating Request messages, but it would only be allowed to be included when the UE was in Iu mode (i.e. universal terrestrial radio access network, UTRAN). There is a limit to the size of the Location Updating Request when the UE is in A/Gb mode (i.e. in GSM / EDGE radio access network, GERAN). The size of the Location Updating Request message is limited to 20 octets when the UE is in A/Gb mode. The effect is that there is no available "feature support bit" in the Location Updating Request message when the UE is in A/Gb mode. This is accommodated in embodiments of the present invention by allowing the network to determine if the Location Updating Request message includes the "feature support bit". If the Location Updating Request message does not include the “feature support bit” (either because the UE does not in fact support the alternative emergency number list IE, or because the UE does support the alternative emergency number list but is connected in A/Gb mode), then the network just acts as though the UE does not support the new emergency service categories and returns the existing emergency number support list including emergency numbers with the new emergency service categories removed, and optionally with existing service categories.

In a further embodiment of the present invention, when the UE is connected to the network in the CS domain the new emergency categories may be included in the emergency setup message sent to the network when connecting an emergency call as a new emergency category IE as shown in Figure 14, with or without the existing emergency category IE illustrated in Figure 1.

Referring now to Figure 4, this is a sequence flow diagram illustrating a first scenario for actions performed at the UE and a MME / SGSN in accordance with an embodiment of the present invention. The UE is connected to the network in the PS domain. Figure 4 shows a list of emergency numbers stored in the network and one or more service category associated with each emergency number, for instance "114" and "Mountain Rescue". It will be appreciated that only existing emergency service categories defined by 3GPP TS 22.101 are associated with the numbers in the list of Figure 4. The sequence begins at the UE, which is configured to support the new emergency service categories defined in RFC 5031. The UE begins by sending a message to the network including an indication that the UE supports the alternative emergency number list IE, specifically by sending a "New emergency service category Supported Indication" in an LTE Attach / GPRS Attach / TAU / RAU (or alternatively a Location Updating Request message). The "indication" may comprise a "feature support bit" as described above. In response, the network, and specifically the MME / SGSN determines that none of the emergency numbers stored in the network are associated with new emergency service categories, and so it is appropriate to send an existing emergency number list IE to the UE in an Accept message (that is, instead of sending an alternative emergency number list IE). Although not shown in Figure 4, the UE will then store and use the emergency number list IE for handling future emergency calls.

Referring now to Figure 5, this is a sequence flow diagram illustrating a second scenario for actions performed at the UE and a MME / SGSN in accordance with an embodiment of the present invention. The UE is connected to the network in the PS domain. Figure 5 shows a list of emergency numbers stored in the network and one or more service category associated with each emergency number, for instance "115" and "Animal Control". It will be appreciated that only new emergency service categories defined by RFC 5031 are associated with the numbers in the list of Figure 5. As for Figure 4, the sequence begins at the UE, which is configured to support the new emergency service categories defined in RFC 5031 and sends a message to the network including an indication that the UE supports the alternative emergency number list IE. In response, the network determines that all of the emergency numbers stored in the network are only associated with new emergency service categories, and so it is appropriate to send an alternative emergency number list IE to the UE in an Accept message.

Referring now to Figure 6, this is a sequence flow diagram illustrating a third scenario for actions performed at the UE and a MME / SGSN in accordance with an embodiment of the present invention. The UE is connected to the network in the PS domain. Figure 6 shows a list of emergency numbers stored in the network and one or more service category associated with each emergency number, for instance "115" and "Animal Control". It will be appreciated that both existing emergency service categories defined by 3GPP TS 22.101 and new emergency service categories defined by RFC 5031 are associated with the numbers in the list of Figure 6. However, each emergency number is only associated with either one or more existing emergency service categories or a new emergency service category. As for Figures 4 and 5, the sequence begins at the UE, which is configured to support the new emergency service categories defined in RFC 5031 and sends a message to the network including an indication that the UE supports the alternative emergency number list IE. In response, the network determines that at least some of the emergency numbers stored in the network are associated with existing emergency service categories and some of the emergency numbers are associated with new emergency service categories, and so it is appropriate to send an alternative emergency number list IE to the UE in an Accept message.

Referring now to Figure 7, this is a sequence flow diagram illustrating a fourth scenario for actions performed at the UE and a MME / SGSN in accordance with an embodiment of the present invention. The UE is connected to the network in the PS domain. Figure 7 shows a list of emergency numbers stored in the network and one or more service category associated with each emergency number, for instance "115" and "Police, Ambulance". It will be appreciated that both existing emergency service categories defined by 3GPP TS 22.101 and new emergency service categories defined by RFC 5031 are associated with the numbers in the list of Figure 6. At least one emergency number is associated with both an existing emergency service category and a new emergency service category. As for Figures 4 to 6, the sequence begins at the UE, which is configured to support the new emergency service categories defined in RFC 5031 and sends a message to the network including an indication that the UE supports the alternative emergency number list IE. In response, the network determines that at least some of the emergency numbers stored in the network are associated with existing emergency service categories and some of the emergency numbers are associated with new emergency service categories, and so it is appropriate to send an alternative emergency number list IE to the UE in an Accept message.

Figure 8 illustrates the encoding of a first set of emergency number information forming part of an alternative emergency number list according to Figure 3. The encoding relates to emergency number "188" shown in Figure 7, and which is associated with "Mountain Rescue" (an existing emergency service category) and "Animal Control" (a new emergency service category). The top part of Figure 8 shows the encoding for “Mountain Rescue” within an existing emergency service category value octet of an alternative emergency number list IE. Mountain Rescue maps to a single bit set to "1": the fifth bit of the existing emergency service octet. The second part of Figure 8 shows the encoding for "Animal Control" within a new emergency service category value octet of an alternative emergency number list IE. Animal Control maps to a single bit set to "1": the first bit of the new emergency service octet. The last part of Figure 8 shows the emergency number information for "188", encoded as described above and in connection with Figure 3.

Figure 9 illustrates the encoding of a second set of emergency number information forming part of an alternative emergency number list according to Figure 3. The encoding relates to emergency number "161" shown in Figure 7, and which is associated with "Gas, Poison" (both new emergency service categories). The top part of Figure 9 shows the encoding for the existing emergency number category value, all of the bits of which are set to "0". The second part of Figure 9 shows the encoding for "Gas, Poison" within a new emergency service category value octet of an alternative emergency number list IE. Gas and Poison map to the second and fourth first bits of the new emergency service octet being set to "1". The last part of Figure 9 shows the emergency number information for "188", encoded as described above and in connection with Figure 3.

Figure 10 is a sequence flow diagram illustrating a first scenario for actions performed at the UE and a MSC during an IMSI Attach / Location Update Request and response in accordance with an embodiment of the present invention when the UE is connected to the network in UTRAN. The UE is connected to the network in the CS domain. Figure 10 illustrates a scenario in which the network stores the same emergency numbers as in the scenario of Figure 7 described above. The sequence begins at the UE, which is configured to support the new emergency service categories defined in RFC 5031 and is connected to the network in UTRAN. The UE sends a message to the network including an indication that the UE supports the alternative emergency number list IE. In response, the network determines that at least some of the emergency numbers stored in the network are associated with existing emergency service categories and some of the emergency numbers are associated with new emergency service categories, and so it is appropriate to send an alternative emergency number list IE to the UE in an Accept message.

Figure 11 is a sequence flow diagram illustrating a second scenario for actions performed at the UE and a MSC during an IMSI Attach / Location Update Request and response in accordance with an embodiment of the present invention when the UE is connected to the network in GERAN. The UE is connected to the network in the CS domain. Figure 11 illustrates a scenario in which the network stores the same emergency numbers as in the scenario of Figure 10 described above. The sequence begins at the UE, which is configured to support the new emergency service categories defined in RFC 5031 and is connected to the network in GERAN. Due to the limit to 20 octets for Location Updating Request messages described above for GERAN the UE is unable to send an indication to the network that the UE supports the alternative emergency number list IE. In response, the network determines that although at least some of the emergency numbers stored in the network are associated with new emergency service categories, it is necessary to send an existing emergency number list IE to the UE in an Accept message. Emergency numbers having only associated new emergency service categories, for instance "134" and "Poison", are included in the existing emergency number list IE as having a NULL service category. In the event of the user selecting "134" this results in the emergency call being connected by the network to a default PSAP. For emergencies numbers having both an associated existing emergency service category and an associated new emergency service category, for instance "128" and "Fire Brigade, Physician" these are included in the existing emergency number list IE with only the existing emergency service category, for instance "Fire Brigade". In the event of the user selecting "128" this results in the emergency call being connected by the network to the PSAP associated with "Fire Brigade". Effectively, in the scenario of Figure 11 the UE operates as a legacy UE which does not support the alternative emergency number list IE. In such a scenario the risk of an emergency call being connected to an inappropriate PSAP may be minimised by not associating numbers with an emergency service category and a new emergency service category.

Figure 12 is a sequence flow diagram illustrating actions performed at the UE and a MSC during an emergency setup in accordance with an embodiment of the present invention. The UE is connected to the network in the CS domain (that is in UTRAN). Additionally, Figure 12 includes a table indicating what existing emergency service categories or new emergency service categories are included in an emergency set up message when a user dials numbers that map to particular categories. The UE supports the alternative emergency number list and the SIM/USIM/ME is configured with or has downloaded from the network numbers with new emergency service categories in an alternative emergency number list. In the event that the user dials a number that maps only to a new emergency service category, for instance "Gas" then the emergency setup message includes only one or more respective new emergency service categories. If an alternative number is dialled then it may be that only one or more emergency service category is included, or one or more of both existing emergency service categories and new emergency service categories may be included.

Figure 13 illustrates an emergency setup message according to an embodiment of the present invention such as may be sent in the CS domain emergency call connection scenario of Figure 12. In accordance with an embodiment of the present invention the emergency setup message may include an existing emergency service category IE as described above in connection with Figure 1, and as described in section 9.3.8.4 of TS 24.008 and may include a new emergency category IE as described above and as illustrated in Figure 14. The existing emergency service category IE is included if the existing emergency service category is available from the SIM/USIM or the ME. If the existing emergency service category IE is included, it indicates the selected existing emergency call category. The existing emergency service category IE may be included together with a new emergency service category IE. The new emergency service category IE is included if a new emergency service category is available from the SIM/USIM or the ME. If the new emergency service category IE is included, it indicates the selected new emergency service call category. The new emergency service category IE may be included together with an existing service emergency category IE. If an existing emergency service category IE is not included and a new emergency category IE is not included, the network defaults to assuming a non-specific emergency call and connects the emergency call to a default PSAP.

Referring now to Figure 14, this illustrates a new emergency service category IE that may optionally be included in an emergency set up message. The encoding of the new emergency service category IE is generally the same as for the existing emergency service category IE described above in connection with Figure 1, and so similar encoding aspects will not be described again. Additionally the encoding for both an existing emergency service category IE and as applicable a new emergency service category IE is generally described in connection with Figure 10.5.x/3GPP TS 24.008 and table 10.5.135d/3GPP within 3GPP TS 24.008. The purpose of the new emergency service category IE is to provide the network with information about services invoked by the user equipment. The new emergency service category IE is a type 4 information element with a minimum length of 3 octets. With reference to the new emergency service category value (octet 3), bits 1 to 4 are coded are derived from usage of the sub-service type in RFC 5031. A UE may set one or more of bits 1 to 4 of octet to "1". If more than one bit is set to "1", routing to a combined PSAP (for instance Poison and Gas ) is required. If the MSC cannot match the received service categories to any of the emergency centres, it is arranged to route the call to an operator defined default PSAP. If no bit is set to "1", the MSC is arranged to route the emergency call to an operator defined default PSAP:

Bit 1 Animal Control

Bit 2 Gas

Bit 3 Physician

Bit 4 Poison

Bits 5 to 8 are spare and set to "0".

Implementation of the alternative emergency number list within the UICC (Universal Integrated Circuit Card) will now be described. This may be through specification of a new EF file in the USIM/SIM card or by extending the existing EF file defined in 3GPP TS 31.102 v11.1.0 (2012-03) 3rd Generation Partnership Project; Technical Specification Group Core Network and Terminals; Characteristics of the Universal Subscriber Identity Module (USIM) application (Release 11)" available from www.3GPP.org. Section 4.2.21 of 3GPP TS 31.102 describes how an EFECC is arranged to contain emergency call codes. As the EF is mandatory already for UEs compliant with 3GPP TS 31.102, in certain embodiments of the invention it is preferable to extend the EFECC by the addition of an extra octet to encode the new emergency service categories. Alternatively, an entirely new EF may be specified to replace the EFECC referred to as an EFXECC (extended emergency call codes EF) as illustrated in Figure 15. Except for the addition of the last line and a new Identifier (shown in Figure 15 as "Identifier: 'xxxx'"), the EFXECC is the same as the EFECC. An operator would either configure an EFECC or an EFXECC but not both EFs in a UE. The EFXECC shown in Figure 15 encodes the emergency numbers as Emergency Call Codes, encodes an "Alpha Identifier" comprising information to be displayed on the screen to the user when the emergency number is selected, the emergency service categories and the new emergency service categories for that emergency number.

Referring now to Figure 16, this is a flow chart illustrating logic implemented in an UE at switch on. The same logic is also use for Tracking Area Update, Routing Area Update and Location Area Update (Location Updates). At step 1610 the UE camps in a cell. At step 1620 the UE initiates an initial attach procedure. At step 1630 the UE determines if it supports new emergency service categories. If yes then at step 1640 the UE determines if it is in a GERAN cell. It no then at step 1650 the UE includes an "new emergency service categories supported indication" in the initial attach message sent to the network, for instance by setting a "feature supported" bit, as described above. However, if at step 1630 the determination is that the UE does not support the new emergency service categories or at step 1640 the determination is that the UE is in a GERAN cell (causing the default to legacy UE behaviour described above) then no such indication is included in the initial attach message. At step 1660 the attach procedure continues.

Referring now to Figure 17, this is a flow chart illustrating logic implemented in an MME/SGSN/MSC on UE Attach/Updating. At step 1710 the network node receives the initial attach message and at step 1720 the network node determines if a new emergency category support indication is included. If no the network carries on with a conventional Attach/Updating Accept message at step 1770. If yes then at step 1730 the network node determines if the network only has emergency numbers associated with existing service categories. If yes then at step 1740 the network returns an existing emergency number list IE within an Attach/Updating Accept message. If no at step 1750 the network determines if some emergency numbers are associated with new emergency service categories. If yes then at step 1760 the network node returns an alternative emergency number list IE within an Attach/Updating Accept message. If no then at step 1770 the conventional attach procedure continues.

Upon the UE receiving an alternative emergency number list IE in an Attach/Updating Accept message UE implementation processes the alternative emergency number list IE. Conventional UE emergency number and emergency service category mapping is extended to support indexing for the new emergency service categories.

When the UE makes an emergency call in the PS domain the MMI mode display supports display of the existing service categories for this MMI mode for making emergency calls and will consequently also display the new emergency service categories if they are supported by the UE. The UE will use its existing mechanism for mapping a dialled number to an emergency service category, but now includes the new emergency service categories in the result of the mapping as required. When the user makes a PS emergency call with a number that maps only to one old or one new service category, the UE will add the corresponding "sub-service" to the Request-URI. Alternatively, when the user makes a PS emergency call with a number that maps to more than one existing or new emergency service category, the UE implementation in one embodiment of the invention may display a pop-up a window with the available service categories to allow the user to choose exactly which service is required. On user selection the UE adds the corresponding "sub-service" to the Request-URI.

Figure 18 illustrates in the form of three flow charts the logic for when the UE makes a CS domain (UTRAN) emergency call. At step 1810 the UE supports new emergency service categories and the SIM / USIM is configured or has downloaded numbers with new emergency service categories. At step 1820, if the user dials a number that maps only to a new emergency service category, At step 1850, only the new emergency service category IE is included in the emergency setup message sent to the network. At step 1830, if the user dials a number that maps only to an existing emergency service category, At step 1860, only the existing emergency service category IE is included in the emergency setup message sent to the network. At step 1840, if the user dials a number that maps to both an existing emergency service category and a new emergency service category, At step 1870 both the existing emergency service category IE and the new emergency service category IE are included in the emergency setup message sent to the network.

Refering to 19, the wireless communication system supports existing emergency service categories associated with emergency numbers the wireless communication system comprise a UE 1910 and a network node 1930. The UE 1910 comprise a communication unit 1912 and a control unit 1914. The communication unit 1912 has wireless communication function, and communicate with the network node 1930. The control unit 1914 may transmit an indication if the UE 1910 supports new emergency service categories to the network node 1930 through the communication unit 1912. If the UE 1910 does support new emergency service categories the control unit 1914 is arranged to receive an existing emergency number list from the network node comprising at least one emergency number and zero, one or more associated existing emergency service categories. If no emergency number stored in the network node to be transmitted to the UE 1910 has an associated new emergency service category, and the the control unit 1914 may receive an alternative emergency number list from the network node and to not receive an existing emergency number list, the alternative emergency number list comprising at least one emergency number associated with at least one new emergency service category if the network node stores at least one emergency number having an associated new emergency service category. If the UE 1910 does not support new emergency service categories, the control unit 1914 may receive an existing emergency list from the network node comprising at least one emergency number and zero, one or more associated existing emergency service categories

THE network node 1930 comprises the communication unit 1932 and a control unit 1934. The control unit 1934 may receive from the UE an indication if the UE 1910 supports new emergency service categories. The control unit 1934 may determine if the UE 1910 supports new emergency service categories. If the network node determines that the UE does support new emergency service categories the The control unit 1934 may determine to transmit an existing emergency number list, to the UE 1910 comprising at least one emergency number and zero, one or more associated existing emergency service categories if no emergency number to be transmitted to the UE 1910 has an associated new emergency service category, and determine to transmit an alternative emergency number list to the UE 1910 and to not transmit an existing emergency number list, the alternative emergency number list comprising at least one emergency number associated with at least one new emergency service category if the network node stores at least one emergency number having an associated new emergency service category. If the network node 1930 determines that the UE 1910 does not support new emergency service categories, the control unit 1934 may determine to transmit an existing emergency list to the UE comprising at least one emergency number and zero, one or more associated existing emergency service categories.

It will be appreciated that embodiments of the present invention described above related specifically to 3GPP compliant cellular wireless communications systems and to particular 3GPP Technical Specifications. However, the present invention is more widely applicable and relates to any such cellular wireless communications systems whereby existing service categories have been defined for emergency calls originally operated on a specific domain (e.g. CS), without foresight that newer emergency categories could be created when emergency calls are supported over other domains (e.g. PS),.. Embodiments of the present invention address the issue of inability of the USIM/ME/Network/Protocol to now support new emergency service categories.

It will be appreciated that embodiments of the present invention can be realized in the form of hardware, software or a combination of hardware and software. Any such software may be stored in the form of volatile or non-volatile storage such as, for example, a storage device like a ROM, whether erasable or rewritable or not, or in the form of memory such as, for example, RAM, memory chips, device or integrated circuits or on an optically or magnetically readable medium such as, for example, a CD, DVD, magnetic disk or magnetic tape or the like. It will be appreciated that the storage devices and storage media are embodiments of machine-readable storage that are suitable for storing a program or programs comprising instructions that, when executed, implement embodiments of the present invention. Accordingly, embodiments provide a program comprising code for implementing apparatus or a method as claimed in any one of the claims of this specification and a machine-readable storage storing such a program. Still further, such programs may be conveyed electronically via any medium such as a communication signal carried over a wired or wireless connection and embodiments suitably encompass the same.

Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of them mean "including but not limited to", and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. It will be also be appreciated that, throughout the description and claims of this specification, language in the general form of "X for Y" (where Y is some action, activity or step and X is some means for carrying out that action, activity or step) encompasses means X adapted or arranged specifically, but not exclusively, to do Y.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

Claims

A method of providing support for the execution of emergency calls in a wireless communications system comprising user equipment, UE, and a network node, where the wireless communication system supports existing emergency service categories associated with emergency numbers, the method comprising:

transmitting from the UE to the network node an indication if the UE supports new emergency service categories; and

determining at the network node if the UE supports new emergency service categories;

wherein if the network node determines that the UE does support new emergency service categories the method further comprises:

determining at the network node to transmit an existing emergency number list, to the UE comprising at least one emergency number and zero, one or more associated existing emergency service categories if no emergency number to be transmitted to the UE has an associated new emergency service category; and

determining at the network node to transmit an alternative emergency number list to the UE and to not transmit an existing emergency number list, the alternative emergency number list comprising at least one emergency number associated with at least one new emergency service category if the network node stores at least one emergency number having an associated new emergency service category; and

wherein if the network node determines that the UE does not support new emergency service categories the method further comprises:

determining at the network node to transmit an existing emergency list to the UE comprising at least one emergency number and zero, one or more associated existing emergency service categories.
A method according to claim 1, wherein the alternative emergency number list includes at least one emergency number, each emergency number being associated with zero, one or more existing emergency service categories and further associated with zero, one or more new emergency service categories.
A method according to claim 1 or claim 2, wherein each existing emergency service category comprises an emergency service category as specified in section 10 of 3GPP TS 22.101 and each new emergency service category comprises an emergency service category corresponding to a sub-service described in IETF RFC 5031 and which is not an emergency service category as specified in 3GPP TS 22.101.
A method according to any one of the preceding claims, wherein transmitting from the UE to the network node an indication if the UE supports new emergency service categories comprises including a new-emergency-service-category-supported indication within an EPS/GPRS Attach message or a Tracking Area Update/Routing Area Update or a Location Update message transmitted from the UE to the network if the UE supports the use and storage of an alternative emergency number list IE.
A method according to any one of the preceding claims, further comprises determining at the UE whether a telephone number dialled by a user comprises an emergency number, and if so transmitting an emergency request to the network node, wherein if the UE supports new emergency service categories the method further comprises determining whether the emergency number is associated with one or more existing emergency service category and determining whether the emergency number is associated one or more new emergency service category, and if so incorporating at least one associated existing emergency service category or new emergency service category within the emergency request sent to the network node.
A method according to claim 5, wherein if the emergency request is sent to the network node in the CS domain an emergency setup message is transmitted to the network node including zero, one or more existing emergency service category information elements, IEs, and zero, one or more new emergency service category IEs and if the emergency request is sent to the network node in the PS domain an emergency INVITE message is transmitted to the network node including an emergency service URN and zero or one sub-service type.
A method according to claim 5 or claim 6, wherein if the UE determines that the emergency number dialled by the user is associated with more than one existing emergency service category or new emergency service category, and if the UE further determines that the selected domain for connecting the emergency call to the network cannot transmit more than one emergency service category, the method further comprises the UE further providing the ability for the user to select a single existing emergency service category or new emergency service category from the associated emergency service categories, and the UE transmitting the selected emergency service category to the network node.
A method according to any one of the preceding claims, wherein transmitting from the UE to the network node an indication if the UE supports new emergency service categories comprises determining if the UE is connected to the network in UTRAN and if so including an indication that the new emergency service categories are supported to the network node within in a location update message.
A method according to any one claims 1 to 7, wherein transmitting from the UE to the network node an indication if the UE supports new emergency service categories comprises determining if the UE is connected to the network in GERAN and if so the method further comprises not including an indication whether the new emergency service categories are supported to the network node within a location update message.
A method according to any one of the preceding claims, further comprising storing within a SIM / USIM card within the UE at least one emergency number associated with zero, one or more existing emergency service category and zero, one or more new emergency service categories.
A method according to claim 10, further comprising configuring the SIM / USIM card with the associated zero, one or more existing emergency service categories and zero, one or more new emergency service categories within an existing emergency call code elementary file EFECC extended to specify the zero, one or more new emergency service category or within an extended emergency call code elementary file EFXECC.
A method according to claim 11, further comprising transmitting an emergency request to the network node and incorporating each associated existing emergency service category and each associated new emergency service category within the emergency request sent over the to the network node by comparing an emergency number dialled by a user with the information stored in the EFECC or EFXECC.
A method according any one of the preceding claims, wherein the existing emergency number list IE is as specified in section 10.5.4.33 of 3GPP TS 24.008 and the alternative emergency number list IE is as specified in section 10.5.4.33 of 3GPP TS 24.008 and further comprising at least one alternative emergency service category value octet associated with each emergency number encoding associated new emergency service categories for each emergency number.
A method according any one of the preceding claims, wherein the alternative emergency number list IE is as specified in section 10.5.4.33 of 3GPP TS 24.008 and wherein at least one of bits 6 to 8 of the emergency service category value octet associated with each emergency number encodes an associated new emergency service category for each emergency number.
A method of providing support for the execution of emergency calls within a UE in a wireless communications system which further comprises a network node, the wireless communication system supporting existing emergency service categories associated with emergency numbers, the method comprising:

transmitting from the UE to the network node an indication if the UE supports new emergency service categories arranged to allow the network node to determine if the UE supports new emergency service categories;

receiving at the UE an existing emergency number list comprising at least one emergency number and zero, one or more associated existing emergency service categories if no emergency number stored at the network node to be transmitted to the UE has an associated new emergency service category or if the UE does not indicate to the network node that it supports new emergency service categories; and

receiving at the UE an alternative emergency number list and not receiving at the UE an existing emergency number list, the alternative emergency number list comprising at least one emergency number associated with at least one new emergency service category if the network node stores at least one emergency number to be transmitted to the UE having an associated new emergency service category and the UE indicates to the network node that it supports new emergency service categories.
A method of providing support for the execution of emergency calls within a network node in a wireless communications system which further comprises user equipment, UE, the wireless communication system supporting existing emergency service categories associated with emergency numbers, the method comprising:

receiving at the network node from the UE an indication if the UE supports new emergency service categories; and

determining at the network node if the UE supports new emergency service categories;

wherein if the network node determines that the UE does support new emergency service categories the method further comprises:

determining at the network node to transmit an existing emergency number list, to the UE comprising at least one emergency number and zero, one or more associated existing emergency service categories if no emergency number to be transmitted to the UE has an associated new emergency service category; and

determining at the network node to transmit an alternative emergency number list to the UE and to not transmit an existing emergency number list, the alternative emergency number list comprising at least one emergency number associated with at least one new emergency service category if the network node stores at least one emergency number having an associated new emergency service category; and

wherein if the network node determines that the UE does not support new emergency service categories the method further comprises:

determining at the network node to transmit an existing emergency list to the UE comprising at least one emergency number and zero, one or more associated existing emergency service categories.
A wireless communications system arranged to provide support for the execution of emergency calls, the wireless communication system supporting existing emergency service categories associated with emergency numbers, the wireless communications system comprising:

UE; and

a network node;

wherein the UE is arranged to transmit to the network node an indication if the UE supports new emergency service categories and to receive from the network node an existing emergency number list or an alternative emergency number list;

wherein the network node is arranged to determine if the UE supports new emergency service categories;

wherein if the network node determines that the UE does support new emergency service categories the network node is further arranged to determine to transmit an existing emergency number list, to the UE comprising at least one emergency number and zero, one or more associated existing emergency service categories if no emergency number to be transmitted to the UE has an associated new emergency service category, and to determine to transmit an alternative emergency number list to the UE and to not transmit an existing emergency number list, the alternative emergency number list comprising at least one emergency number associated with at least one new emergency service category if the network node stores at least one emergency number having an associated new emergency service category; and

wherein if the network node determines that the UE does not support new emergency service categories the network node is further arranged to determine to transmit an existing emergency list to the UE comprising at least one emergency number and zero, one or more associated existing emergency service categories.
A UE within a wireless communications system which further comprises a network node, the UE being arranged to provide support for the execution of emergency calls, the wireless communication system supporting existing emergency service categories associated with emergency numbers:

wherein the UE is arranged to transmit to the network node an indication if the UE supports new emergency service categories to allow the network node to determine if the UE supports new emergency service categories and to receive from the network node an existing emergency number list or an alternative emergency number list;

wherein if the UE does support new emergency service categories the UE is arranged to receive an existing emergency number list from the network node comprising at least one emergency number and zero, one or more associated existing emergency service categories if no emergency number stored in the network node to be transmitted to the UE has an associated new emergency service category, and the UE is arranged to receive an alternative emergency number list from the network node and to not receive an existing emergency number list, the alternative emergency number list comprising at least one emergency number associated with at least one new emergency service category if the network node stores at least one emergency number having an associated new emergency service category; and

wherein if the UE does not support new emergency service categories the UE is arranged to receive an existing emergency list from the network node comprising at least one emergency number and zero, one or more associated existing emergency service categories.
A network node within a wireless communications system which further comprises a UE, the network node being arranged to provide support for the execution of emergency calls, the wireless communication system supporting existing emergency service categories associated with emergency numbers:

wherein the network node is arranged to receive from the UE an indication if the UE supports new emergency service categories;

wherein the network node is arranged to determine if the UE supports new emergency service categories;

wherein if the network node determines that the UE does support new emergency service categories the network node is further arranged to determine to transmit an existing emergency number list, to the UE comprising at least one emergency number and zero, one or more associated existing emergency service categories if no emergency number to be transmitted to the UE has an associated new emergency service category, and to determine to transmit an alternative emergency number list to the UE and to not transmit an existing emergency number list, the alternative emergency number list comprising at least one emergency number associated with at least one new emergency service category if the network node stores at least one emergency number having an associated new emergency service category; and

wherein if the network node determines that the UE does not support new emergency service categories the network node is further arranged to determine to transmit an existing emergency list to the UE comprising at least one emergency number and zero, one or more associated existing emergency service categories.
A non-transitory computer-readable storage medium having computer readable instructions stored thereon, the computer readable instructions being executable by a computerized device to cause the computerized device to perform the method of processing state information in a radio access network of claim 1.
A non-transitory computer-readable storage medium having computer readable instructions stored thereon, the computer readable instructions being executable by a computerized device to cause the computerized device to perform the method of processing state information in a radio access network of claim 15.
A non-transitory computer-readable storage medium having computer readable instructions stored thereon, the computer readable instructions being executable by a computerized device to cause the computerized device to perform the method of processing state information in a radio access network of claim 16.