WO2014206436A1

WO2014206436A1 - Shortened call setup for multimode wireless access terminals

Info

Publication number: WO2014206436A1
Application number: PCT/EP2013/063095
Authority: WO
Inventors: Johan Hokfelt; Rama Kumar Mopidevi
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2013-06-24
Filing date: 2013-06-24
Publication date: 2014-12-31
Also published as: CN105052240A

Abstract

A portable radio communication apparatus supporting multiple radio access technologies and configured to camp on a first communication access network includes a controller, and a multi-mode radio access technology device coupled to the controller. The controller is configured to detect that the first communication access network on which the multi-mode radio access technology device is currently camped does not support operator-provided voice call service functionality for the multi-mode radio access technology device. The controller is configured to establish a communication link between the multi-mode radio access technology device and a second communication access network capable of supporting operator-provided voice call service functionality for the multi-mode radio access technology device if packet-switched services supported by the first communication access network on which the multi-mode radio access technology device is currently camped are not being used by the multi-mode radio device and are provided to the multi-mode device by a wireless access network.

Description

SHORTENED CALL SETUP FOR MULTEVIODE WIRELESS ACCESS TERMINALS

TECHNICAL FIELD

[0001] The aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to reducing call setup time in a multimode wireless access terminal that camps on networks that do not provide operator-provided voice services.

BACKGROUND ART

[0002] Wireless communication systems provide various types of communication connections and capabilities such as for example, voice and data. These types of communication systems can be accessed by multiple users and support communication and sharing of the available system resources, including for example, bandwidth and transmit power. Examples of multiple access communication systems, also referred to as cellular systems and networks, can include but are not limited to code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, 3GPP Long Term Evolution (LTE) systems and orthogonal frequency division multiple access (OFDMA) systems.

[0003] Some communication systems and devices include multiple radio access technologies for transmitting and receiving on different networks. Examples of different radio access technologies can include, but are not limited to, Universal Mobile Telecommunication Systems (UMTS), Global System for Mobile Communications (GSM), CDMA2000, WiMax,

[0004] Long Term Evolution is a standard for wireless data communications technology.

The development of the LTE standard stems from GSM/UMTS standards. The LTE standard generally increases the capacity and speed of wireless data networks. It includes a simplification of the network architecture to an IP -based system. As the LTE standard only supports packet switching it does not support legacy circuit switched voice calls such as provided by GSM, UMTS and CDMA2000 standards networks. Future generations of LTE networks are however likely to support operator-provided voice services with introduction of technologies such as Voice over LTE (VoLTE).

[0005] Because of the various types of wireless communication networks, a mobile communication device or multimode wireless access terminal, also referred to herein as "user equipment", needs to support wireless communication with and in more than one wireless communication network. While, for purposes of the description herein, a multimode wireless access terminal will be referred to as a "mobile communication device" or "terminal", it will be understood that a multimode wireless access terminal can include any suitable wireless communication device, examples of which include, but are not limited to multimode wireless transmit/receive units, cellular communication devices, smart phones, tablets and phablets.

[0006] A mobile communication device that includes LTE radio access technology can be referred to as a fourth generation (4G) mobile communication device. A 4G mobile communication device can include different radios or radio equipment to provide a variety of different voice and data communication capabilities and functions for the user. As an example, a 4G mobile communication device might include an LTE radio for packet data services, an IEEE 802.1 1 (Wifi) standard radio, a Global Positioning System (GPS) radio and a Bluetooth standard radio. Any one or more of the radios in such a 4G device can be operating simultaneously to provide the different voice communication and data communication services that are provided by such a device.

[0007] As a user of a terminal roams in, among and between different networks, there is preferably a handover of the terminal from one network to a next network in a seamless manner. The service being provided to the terminal preferably should be continuous, and the handover should preferably occur without interruption in the service. As an example, a terminal, or wireless subscriber may be roaming between a WLAN and a 3G network. The coordination between the terminal and the wireless service networks should generally provide service continuity during roaming or movement between different wireless networks.

[0008] Many LTE networks do not yet inherently support voice call services, and, similarly, such voice call services are often not yet supported by the mobile communication devices. Operator-provided voice traffic must hence be handled by legacy networks. One solution for the situation where the mobile communication device is camping on an LTE network and a voice call is about to be set up is circuit switched fallback (CSFB). With circuit switched fallback, when the mobile communication device that supports LTE, UMTS and GSM networks is operating in LTE (data connection) mode and a voice call comes in, the LTE network pages the device. The mobile communication device responds with a special service request to the LTE network, and the LTE network signals the mobile communication device to move, or fall back, to a 2G/3G network to accept the incoming call. A similar procedure takes place with respect to an outgoing call. Thus, in CSFB, the mobile communication device is moved from the LTE network to either a GSM, UMTS or CDMA2000 network, whenever a call setup service is to be performed. This moving from the LTE network applies to both mobile device originated and mobile device terminated call setups.

[0009] However, in these CSFB type solutions, the call setup time is significantly longer than traditional call setup times. Also, the call setup success rate tends to be lower in a CSFB type solution than in a legacy call setup procedure. According to a study entitled "Circuit- switched fall back. The first phase of voice evolution for mobile LTE device", Qualcomm 2012, the call setup times in a CSFB solution such as that described above can be as much as 100% longer than a legacy call setup procedure, increasing from approximately 2.6 seconds to approximately 5.2 seconds. This increase in time is generally undesirable.

[0010] A multimode terminal that camps on an LTE cell will receive high performance packet switched services (PS) from the LTE network. When a call is setup, and the device is moved to e.g. GSM or UMTS, the packet switched service performance degrades. Therefore, it is in general preferable for the terminal to be on the LTE network when circuit switched services are not requested.

[0011] SVLTE (Simultaneous Voice and LTE) is another alternative that addresses the problem of providing voice services to devices that are camping on an LTE network. Although mobile terminals with SVLTE capability do not require any additional voice call setup time as compared to CSFB-like implementations, these devices have additional hardware cost and consume more power. [0012] A need, therefore, exists for a system, device and call setup procedure that minimizes the call setup time for a mobile communication device that camps on a network on which the network operator cannot provide voice call services.

SUMMARY

[0013] As described herein, the exemplary embodiments overcome one or more of the above or other disadvantages known in the art.

[0014] One aspect of the present disclosure relates to a portable radio communication apparatus supporting multiple radio access technologies and configured to camp on a first communication access network. In one embodiment the portable radio communication apparatus includes a controller, and a multi-mode radio access technology device coupled to the controller. The controller is configured to detect that the first communication access network on which the multi-mode radio access technology device is camped does not support operator-provided voice call service functionality for the multi-mode radio access technology device. Before a voice call setup is initiated, a communication link is established between the multi-mode radio access technology device and a second communication access network capable of supporting operator- provided voice call service functionality for the multi-mode radio access technology device if packet-switched services supported by the first communication access network are not being used by the multi-mode radio device and are provided to the multi-mode radio device by a third access network.

[0015] Another aspect of the present disclosure relates to a wireless communication system. In one embodiment, the system includes a first access network supporting packet- switched services, a second access network supporting operator-provided voice call services, a WLAN access point providing packet-switched services, a mobile communication device and a controller. The mobile communication device is camped on the first access network that does not support operator-provided voice call services for the mobile communication device. The controller is configured to determine that the first access network does not support operator- provided voice call services for the mobile communication device; detect that the mobile communication device is receiving packet-switched services from the WLAN access point; and automatically establish a communication link with the second access network when the mobile communication device is not receiving packet-switched services from the first access network.

[0016] A further aspect of the disclosed embodiments relates to a method for wireless communications with a mobile communication device. In one embodiment the method includes receiving packet-switched services from a first communication access network in the mobile communication device; detecting that the first communication access network does not support operator-provided voice call services for the mobile communication device; detecting a second communication access network capable of supporting operator-provided voice call services for the mobile communication device; detecting that the mobile communication device is receiving packet switched services from a wireless local area network; and automatically establishing a communication link with the second communication access network.

[0017] These and other aspects and advantages of the exemplary embodiments will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. Additional aspects and advantages of the invention will be set forth in the description that follows, and in part will be obvious from the description, or may be learned by practice of the invention. Moreover, the aspects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In the drawings: [0019] Figure 1 is a schematic diagram of one embodiment of an exemplary system incorporating aspects of the present disclosure;

[0020] Figure 2 illustrates a mapping of one embodiment of an exemplary cell coverage area in a system incorporating aspects of the present disclosure;

[0021] Figure 3 is an exemplary sequence diagram for setting up a mobile originated voice call with CSFB in a LTE network;

[0022] Figure 4 is an exemplary sequence diagram for setting up a mobile originated voice call in one embodiment of a system incorporating aspects of the present disclosure;

[0023] Figure 5 is a flow diagram of one embodiment of an exemplary process incorporating aspects of the present disclosure; [0024] Figure 6 is a block diagram of one embodiment of a multi-mode radio access technology device incorporating aspects of the present disclosure. DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENTS

[0025] Figure 1 illustrates one embodiment of a wireless communication environment or system incorporating aspects of the present disclosure. In this example, the wireless communication environment or system 100 includes a wireless device 1 10 that is configured to communicate with one or more wireless communication access networks or systems. The wireless device 1 10 can comprise any wireless or mobile communication device, as is generally described herein. Examples of such devices include, but are not limited to, mobile terminals, access terminals, cellular devices, personal digital assistants, wireless modems, handheld devices, laptop computers, tablets, pads, phablets and smart phones. In one embodiment, the wireless or mobile communication device 1 10 is configured to engage in two-way communication with a 2G/3G cellular system 102, a LTE network 104, and a WLAN access point 106, as well as other suitable systems and devices. As will be generally understood, and not further described herein, the mobile communication device 1 10 will include a suitable number of radio devices coupled to antenna(s) to enable the mobile communication device 1 10 to support suitable radio access technologies and radio communication functionality with the wireless communication networks that are generally described herein.

[0026] In one embodiment, the exemplary wireless communication access networks shown in Figure 1 , include, but are not limited to, the 2G/3G cellular network 102, an LTE network 104, also referred to as cells, and a WLAN access point 106. Examples of the 2G/3G cellular network 102 can include but are not limited to, networks supporting operator-provided voice call services, including GSM, WCDMA and CDMA2000, or other such suitable networks. In one embodiment, the 2G/3G network 102 and the LTE network 104, also referred to as the first and second networks, can be operated by the same operator, or partnered operators), while the WLAN access point 106, or the third network, is fully independent of the 2G/3G network 102 and the LTE network 104. In this example, the third network provides over- the-top data services, but no operator-controlled service, such as for example voice. Although only one of each network 102, 104 and WLAN access point 106 is shown in Figure 1 , it will be understood that the aspects of the disclosed embodiments are not so limited, and the system 100 can include more than one of each of the networks 102, 104 and WLAN access point 106. The mobile communication device 110 will include one or more radios, as is generally understood in the art, that allow the mobile communication device 1 10 to communicate with one or more of the networks 102, 104 and 106, either separately or in combination. For example, in one embodiment, the mobile communication device 1 10 is configured to communicate with one or more of the wireless communication networks 102, 104 and WLAN access point 106 substantially simultaneously. The aspects of the present disclosure are directed to a situation where a multimode access terminal, such as mobile communication device 110, is connected to a wireless local area network, such as WLAN access point 106, while camped on a network that cannot obtain or provide (operator provided) voice call services, such as LTE network 104. In this situation, the mobile communication device 1 10 is not using the packet switch services of the LTE network 104, since those are being provided by the WLAN access point 106. In some legacy systems, the mobile communication device 1 10, responsive to a voice call setup request, would be transferred to an access network such as 2G/3G cellular network 102 that can provide voice services. As noted above, this causes significant delay in the call setup process and it may also result in lower call setup success rate. The aspects of the present disclosure are directed to proactively transferring the mobile communication device 110 to an access network that provides voice call services, such as 2G/3G cellular network 102, which advantageously reduces these delays and avoids some causes of call setup failure.

[0027] Figure 2 is a schematic illustration of a mobile communication device 110 migrating within a system 200 that includes different network coverage or cell areas. The network coverage areas or regions include a WCDMA/HSPA network coverage area 202, a LTE network coverage area 204 and a WLAN coverage area 206. The implementation and devices of these coverage areas 202, 204 and 206 will be understood in the art and not further described herein. The shape and area of each of the coverage areas 202, 204 and 206 is not intended to be limited by the particular shape, orientation and configuration of the coverage areas shown in Figure 2. Rather, the particular shapes and coverage of the areas 202, 204, 206 is merely exemplary, and in alternate embodiments, can include any particular shape and size, and encompass any suitably sized geographical area or region.

[0028] In this example, there are three cells providing the WCDMA HSPA 202, LTE 204 and WLAN 206 coverage areas. These cells can include for example, the 2G/3G system 102, the LTE system 104 and the WLAN access point 106 shown in Figure 1. In alternate embodiments, any number of cells can provide the exemplary coverage illustrated in Figure 2. For the purposes of the examples of the disclosed embodiment, the LTE network 104 providing LTE coverage area 204 does not support operator-provided voice call services. [0029] The movement of the mobile communication device 1 10 in Figure 2 is tracked along the path of the line 210. The indication of which network the mobile communication device 1 10 is camped on is indicated by the variations in the style of the line segments making up the line 210. For example, the dashed line segment 212 indicates that the mobile communication device is camped on the LTE network 104. The solid line segment 214 indicates that the mobile communication device 110 is camped on the 2G/3G network 102, which in this example is shown as a WCDMA/HSPA network, while receiving packet switched services from the WLAN access point 106. In one embodiment, this can also be described as the mobile communication device 1 10 camping on both the 2G/3G network 102 and the WLAN access point 106. With respect to the other portions of the line 210, the dashed line segment 216 indicates that the mobile communication device 110 is camped on the LTE network 104, while the solid line segment 218 indicates that the mobile communication device 1 10 is camped on the 2G/3G network 102.

[0030] Referring to the movement of the mobile communication device 1 10 along the path indicated by line 210, in one embodiment, the mobile communication device 1 10 at the point indicated by reference A is within the WCDMA HSPA coverage area 202 and the LTE coverage area 204. In this example, the mobile communication device 1 10 will start out camping on the LTE cell or network 104, and this will be the cellular access as long as the WLAN access point 106, represented by coverage area 206, is not in range.

[0031] When the mobile communication device 1 10 is at the point along the path 210 indicated by reference B, the mobile communication device 1 10 moves into the WLAN coverage area 206. At this point, the mobile communication device 1 10 starts using the WLAN service provided by WLAN access point 106 for packet data connections in a manner that will generally be understood in the art. Although the mobile communication device 1 10 is using the WLAN access point 106 for packet data connections, the mobile communication device 1 10 remains camped on the LTE network 104, as is indicated by the dashed line 212.

[0032] At the point along the line 210 indicated by reference C, the mobile communication device 1 10 moves within the WCDMA HSPA coverage area 202 of the 2G/3G cell or network 102. In accordance with one aspect of the disclosed embodiments, the mobile communication device 1 10 automatically reselects from the LTE network 104 to the 2G/3G network 102. The mobile communication device 1 10 continues to receive packet switched services from the WLAN access point 106 while camped on the 2G/3G network 102. Since the mobile communication device 1 10 is camped on the 2G/3G network 102, the mobile communication device 1 10 can directly setup a voice call on or over the 2G/3G network 102. In a legacy type communication system, the mobile communication device 1 10 would remain camped on the LTE network 104, as long as the cell restriction and handover policies and procedures favor the LTE cell or network 104.

[0033] When the mobile communication device 1 10 reaches the point along the path 210 indicated as reference D, the mobile communication device 1 10 is moving out of the range of the WLAN coverage area 206 and can no longer receive packet services from the WLAN access point 106. When the mobile communication device 1 10 moves out of the WLAN coverage area 206, generally at reference point D, the mobile communication device 1 10 will start using the current cellular access network for packet switched services, which for purposes of this example is the 2G/3G network 102 or WCDMA HSPA network. In alternate embodiments, the current cellular network can be any suitable cellular communication network that enables operator- provided voice call services. However, when the mobile communication device 1 10 is on the 2G/3G network 102 and no longer receiving packet services from the WLA access point 106, the normal cell reselection criteria will apply. In one embodiment, the mobile communication device 1 10 can return to camping on the LTE network 104 if the radio conditions are such that this cell or network selection/reselection is triggered. [0034] Thus, as is indicated by the line referencing the path 210, the dashed parts 212,

216 of the path 210 are indicative of the mobile communication device 1 10 camping on the LTE network 104. The solid parts 214, 218 of the line referencing the path 210 are indicative of the mobile communication device 1 10 camping on the 2G/3G network 102, or other such suitable cellular communication technology network. The aspects of the disclosed embodiments provide for the mobile communication device 1 10 to switch from being camped on the LTE network 104 to a network that allows operator-provided voice services while the mobile communication device 1 10 is receiving packet switched services from the WLAN access point 106 between the points indicated by C and D along path 210. This behavior by the mobile communication device 1 10 in the system 100 incorporating aspects of the disclosed embodiments is different as compared to legacy mobile communication device and system behavior, and advantageously provides for minimizing the call setup time for access terminals that camp on networks that do not offer operator-provided voice services.

[0035] Figure 3 illustrates a simplified signaling diagram illustrating the establishment of a voice call with CSFB in a LTE network. In this example, the mobile communication device 1 10 is currently camping 302 on the LTE network 104, as is generally illustrated in Figure 1. As noted earlier, the LTE network 104 does not support operator-provided voice call services. A voice call setup request is initiated 304. In one embodiment, the LTE network 104 may request the mobile communication device 1 10 to provide radio measurements 306 on other radio access technologies that are within the coverage area(s) of the mobile communication device 110. The LTE network 104 sends 308 a radio resource control (RRC) connection release signal with a redirection message to a 3G or 2G radio network 102, such as the WCDMA/HSPA network of Figure 2. The mobile communication device 1 10 camps 310 on the 3G or 2G network as specified in the RRC connection release signaling with re -direction message. The mobile communication device 110 then establishes 312 the voice call.

[0036] Referring to Figure 4, in one embodiment of the system 100 incorporating aspects of the disclosed embodiments, steps 306 and 308 shown in Figure 3 can be eliminated. The mobile communication device 110 camps 404 on the 3G or 2G network in advance of the voice call setup request while obtaining 402 packet switched services from the WLAN access point 106. Thus, unlike the legacy system described above, according to the aspects of the disclosure, there is no need for the LTE network 104 to request the mobile communication device 110 to provide measurements on other radio access technologies or send a RRC connection release with redirection to 3G or 2G. This is because the mobile communication device 1 10 is already on a network that supports operator-provided voice services. The voice call can be established 406 and the voice call setup time is thus reduced.

[0037] Figure 5 illustrates one embodiment of a process flow incorporating aspects of the present disclosure. In one embodiment, the mobile communication device 1 10 detects 502 that packet switched services are not being provided by the access network on which the mobile communication device 1 10 is currently camped. This can include detecting that packet switched services are being received from an access point other than the access network on which the mobile communication device 1 10 is currently camped. In one embodiment, it is determined 504 whether operator-provided voice call services are available on the current access network. The operator-provided voice call services that may be available must also be compatible with the functionality of the mobile communication device 1 10. For example, if the current access network supports operator-provided voice call services via VoLTE but the mobile communication device 1 10 does not support VoLTE, then the mobile communication device 1 10 will not be able to avail itself of those operator-provided voice call services.

[0038] If it is determined 504 that operator-provided voice call services are available, the mobile communication device remains 512 camped on the current access network. However, if it is determined 504 that such voice call services are not available, it is determined 506 whether there are any suitable cells belonging to an access network that enables operator-provided voice services. This can include determining 506 whether there are any other access networks within range that offer such voice services. In one embodiment, this can include determining that the access networks are operated by the same carrier as the presently registered network on which the mobile communication device 1 10 is camped. For example, the selection of another access network may be based on a network that has the same PLMN ID, or is defined as an equivalent PLMN, as the presently camped network.

[0039] If it is determined 506 that there are not any other suitable cells supporting operator provided voice call services, the mobile communication device 1 10 remains 512 camped on the presently registered access network. However, if it is determined that there is at least one suitable cell supporting operator provided voice call services, a determination or evaluation 508 is made as to whether the ping-pong criteria is satisfied, in order to avoid frequent cell re-selections between the access networks.

[0040] If it is determined 508 that the ping-pong criteria are not satisfied, the mobile communication device 1 10 remains 512 camped on the currently registered access network. However, if is determined 508 that the ping-pong criteria are satisfied or fulfilled, the mobile communication device 1 10 will adjust 510 its cell re-selection criteria to camp on the access network that supports operator-provided voice call services. In one embodiment, any one of a number of suitable cell reselection criteria can be used that will manage the establishment of communication sessions and maintain continuous communication with the mobile communication device 1 10 as it moves, such as along path 210 of Figure 2. These criteria can include or be implemented on the application level, on the Non-Access Stratum level, or on the radio resource control level.

[0041] At the application level, the high level application software in a mobile communication device 1 10 is aware of which networks the mobile communication device 1 10 is connected to, and which services it obtains from the different networks. The aspects of the disclosed embodiments can be implemented by (temporarily) disabling support of all access networks that do not provide voice call services when the following conditions apply.

[0042] In one embodiment, the mobile communication device 1 10 is static or moving at a very low speed. This can include when the mobile communication device 110 is used indoors such as at home, in a building or in an office, for example. The speed of movement of the mobile communication device 1 10 can be estimated by GPS or other existing methods. If the mobile communication device 1 10 is moving at a high speed, or greater than a predetermined threshold amount, speed based methods can be used to determine if it is suitable to start camping on the 2G/3G network 102 instead of the LTE network 104, when the mobile communication device 1 10 obtains packet switched services form the WLAN access point 106.

[0043] In one embodiment, a time -based method can be used to determine whether the mobile communication device 1 10 should move from the LTE network 104 to the 2G/3G network 102, once the mobile communication device 1 10 is receiving packet-switched service from the WLAN access point 106. For example, once the mobile communication device 1 10 obtains packet-switched services from the WLAN access point 106, the mobile communication device 1 10 must wait a predetermined period of time, such as for example approximately 10 seconds, before starting to camp on the 2G/3G network 102 instead of the LTE network 104. After the predetermined period of time has elapsed, the mobile communication device 110 evaluates if the WLAN signal is from the same access point or a different access point and is sufficiently strong. The mobile communication device 1 10 then camps on the 2G/3G network 102 instead of the LTE network 104. In this manner, ping-pong effects between the LTE network 104 and 2G/3G network 102 can be avoided when the mobile communication device 1 10 is moving. Although the predetermined period of time is indicated as being approximately 10 seconds, in alternate embodiments, any suitable time period can be used.

[0044] In one embodiment, the mobile communication device 1 10 is camping on a packet-switched only access network, such as LTE network 104 of Figure 1 , but is also simultaneously accessing packet-switched services from a local access point, for example the WLAN access point 106 of Figure 1. The mobile communication device 1 10 cannot obtain operator-provided voice call services from the LTE network 104. [0045] In one embodiment, the mobile communication device 1 10 supports other access network technologies that enable operator-provided voice call services, and the mobile communication device 1 10 is within coverage range of at least one other such access network. The mobile communication device 1 10 is allowed to register to such other access network, such as the 2G/3G network 102 shown in Figure 1.

[0046] The mobile communication device 1 10, the LTE network 104 and the 2G/3G network 102, support functionality to transfer the mobile communication device 110 from LTE network 104 to 2G/3G network 102 when a voice call service is requested (such as provided by CSFB functionality, for example). [0047] If these conditions apply, the mobile communication device 1 10 will then start to camp on a network that supports operator-provided voice call services. The aspects of the disclosed embodiments are directed to allowing the mobile communication device 1 10 to camp on a cell that belongs to another network, such as the 2G/3G network 102 before the voice call setup request is present. [0048] The aspects of the disclosed embodiments can also be implemented at the modem mobility management level of the mobile communication device 1 10. In one embodiment, the non-access stratum software in a modem can, if aware that the mobile communication device 1 10 is receiving packet-switched services from a WLAN access point, (temporarily) disable support of all access networks that do not support operator-provided voice call services. Prior to disabling this support, the mobile management level can verify that there is coverage from other networks, i.e. any of those supporting operator-provided voice call services. [0049] When the aspects of the disclosed embodiments are implemented at the modem radio resource control level, the access stratum software in a modem can, if aware of that the mobile communication device 1 10 obtains packet switched services from a WLAN access point, such as the WLAN access point 106 of Figure 1 , at least temporarily influence the cell reselection criteria such that cells that belong to voice call capable networks are prioritized over cells that do not support operator-provided voice call services. In this way, the mobile communication terminal 1 10 will be fully aware of all available access network cells, and have the possibility to return to the temporarily down-prioritized networks with minimum delay, once access to the WLAN access point 106 is lost or disabled. [0050] Referring to Figure 6, in one embodiment, a processor or controller 602 can be coupled to the mobile communication device 110 to perform the various functions and process generally described herein. Although only a single processor is shown in the example of Figure 6, it will be understood that the processor 602 can include any number of processors, controllers and memory devices. In one embodiment, the processor 602 controls the operation of the mobile communication device 1 10. While the processor 602 is described as coupled to the mobile communication device 1 10, in one embodiment, the processor 602 is integrated within or is part of the mobile communication device 110. In one embodiment, the processor 602 includes or is coupled to a memory device 604, that includes a computer readable medium storing computer executable instructions, that when executed on or by the processing device 602, are configured to execute and implement the functions and processes generally described herein. In one embodiment, the processor 602 can store program code and data for the mobile communication device 1 10. The memory device 604 can also be part of or coupled to a database 606 that can store information related to the mobile communication device 110 and the various networks 102, 104 and 106, with which the mobile communication device 110 is configured to communicate. The processor 602 can be implemented on one or more integrated circuits (IC) or application specific integrated circuits (ASIC). In one embodiment the processor 602 comprises a computer- readable medium having non-transitory program code recorded thereon, the program code carry out the process and methods described herein when executed in the processor 602.

[0051] The aspects of the disclosed embodiments will enable a mobile communication device to start to camp on a cell that belongs to an access network that supports operator- provided voice call services even before the voice call setup request is present. This will minimize the call setup time for a mobile communication device 1 10 that is camped on a network that does not support operator-provided voice call services that are compatible with or suitable for the mobile communication device 1 10, particularly when the call setup time is related to CSFB or CSFB-like functionality. By proactively transferring the mobile communication device 1 10 to an access network on which it can directly setup voice call services, while remaining connected to a WLAN access point, the call setup time is noticeably reduced. Thus, in one embodiment, the mobile communication device 110 will be automatically switched to camp on a cell that belongs to an access network that can support operator-provided voice call services when the device is receiving packet switched services from WLAN access point. This avoids the time penalty imposed by the circuit switched fallback procedure, which in some cases has been shown to be as much as 2.5 seconds, as is indicated in the report entitled "Circuit-switched fall back. The first phase of voice evolution for mobile LTE device", Qualcomm 2012. The aspects of the disclosed embodiments substantially eliminate the entire penalty related to CSFB, and the mobile -terminated call setup time for a mobile communication device that camps on an LTE network and is transferred to a UMTS/UTRAN cell can be improved by up to approximately 48%. For mobile-originated call setup, the corresponding improvement is approximately 38% for UMTS/UTRAN transfer and approximately 40% for GSM/GERAN transfer, respectively.

[0052] Thus, while there have been shown, described and pointed out, fundamental novel features of the invention as applied to the exemplary embodiments thereof, it will be understood that various omissions and substitutions and changes in the form and details of devices and methods illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit and scope of the invention. Moreover, it is expressly intended that all combinations of those elements and/or method steps, which perform substantially the same function in substantially the same way to achieve the same results, are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.

Claims

CLAIMS What is claimed is:

1. A portable radio communication apparatus supporting multiple radio access technologies and configured to camp on a first communication access network, comprising: a controller; and

a multi-mode radio access technology device coupled to the controller, wherein the controller is configured to:

detect that the first communication access network on which the multi-mode radio access technology device is currently camped does not support operator-provided voice call service functionality for the multi-mode radio device; and

before a voice call setup is initiated, establish a communication link between the multi-mode radio device and a second communication access network supporting operator-provided voice call service functionality for the multi-mode radio access technology device when it is detected that the multi-mode radio device is receiving packet-switched services from a wireless access network.

2. The portable radio communication device of claim 1 , wherein the first communication access network is an LTE network.

3. The portable radio communication device of claim 2, wherein the second communication access network is one of a GSM, CDMA2000 or WCDMA HSPA network.

4. The portable radio communication device of claim 1, wherein the wireless access network is a WLAN access point.

5. The portable radio communication device of claim 1 , wherein the first communication access network is packet-switched only network.

6. The portable radio communication device of claim 1, wherein the controller is configured to detect that the multi-mode radio device is moving above a predetermined speed and delay a switching from the first communication access network to the second

communication access network.

7. The portable communication device of claim 1, wherein the controller is configured to delay a switching from the first communication access network to the second communication access network for a predetermined time when the multi-mode radio device is receiving packet-switched services from the wireless network.

8. A wireless communication system, comprising:

a first access network supporting packet-switched services;

a second access network supporting operator-provided voice call services;

a WLAN access point providing packet-switched services;

a mobile communication device camped on the first access network; and a controller configured to:

determine that the first access network does not support operator-provided voice call services for the mobile communication device;

detect that the mobile communication device is receiving packet-switched services from the WLAN access point; and

automatically establish a communication link with the second access network when the mobile communication device is not receiving packet-switched services from the first access network.

9. The wireless communication device of claim 8, wherein the first access network is an LTE network that does not support operator-provided voice call services for the mobile communication device.

10. The wireless communication system of claim 8, wherein the second access network is one of a GSM, CDMA2000 or WCDMA HSPA network.

11. The wireless communication system of claim 8, wherein the controller is configured to determine that the mobile communication device is moving at less than a predetermined speed within a coverage range of the first and second networks prior to enabling a switching of the mobile communication device from the first access network to the second access network.

12. The wireless communication system of claim 8, wherein the controller is configured to delaying a switching of the mobile communication device from the first network to the second network for a predetermined period of time after the mobile communication device receives packet-switched service from the WLAN access point.

13. A method for wireless communications with a mobile communication device, comprising:

camping on a first communication access network to receive packet-switched services; detecting that the first communication access network does not support operator-provided voice call services for the mobile communication device;

detecting a second communication access network capable of supporting operator- provided voice call services for the mobile communication device;

detecting that the mobile communication device is receiving packet switched services from a wireless local area network; and

automatically establishing a communication link with the second communication access network.

14. The method of claim 13, comprising determining that the packet-switched services of the first communication access network are not being used by the mobile

communication device prior to establishing the communication link with the second

communication access network.

15. The method of claim 13, wherein the first communication network is a LTE network, the second communication network is a 2G/3G network and the wireless local area network is a WLAN access point.