HK1128579B - Method and apparatus for re-establishing wireless communication sessions - Google Patents

Description

Method and apparatus for reestablishing a wireless communication session

Technical Field

The present invention relates to maintaining or reestablishing a communication session in a wireless communication system.

Background

As access bandwidth and applications have developed and become more popular, the use of packet-switched based real-time communications via the internet has increased. Examples include, for example, internet telephony using voice over internet protocol (VoIP), and popular applications such as Skype^TMAnd video conferencing. However, these types of calls delay the transferOr loss/dropping, has a high sensitivity and the delay or loss/dropping of these transmissions affects the quality and actual vitality of the service.

This problem is particularly exacerbated when the above-described techniques are employed over a radio access network or link, for example for use on small portable devices such as mobile telephones, Personal Digital Assistants (PDAs) or even laptop computers. Wireless access technologies such as Wi-Fi (IEEE802.11) or bluetooth may be used in homes or in public places such as offices, cafes, airports, hotels, and shopping malls. The radio access technology has a number of characteristics that are detrimental to packet-based real-time communication, including generally less bandwidth than the rest of the overall communication path, and increased delays, dropped packets, and dropped calls due to noise and hence less reliable propagation. As electronic devices are increasingly being provided with two or more wireless network capabilities, there are a number of mechanisms for re-routing calls through other networks when a call on one wireless network fails (e.g., the portable handset moves out of range). This problem can also affect non-real-time communication services such as mail.

US2003/3134638 discloses a communication system with linked WLAN and WWAN (wireless wide area network) base stations to which a mobile phone or similar electronic device can be connected. The mobile device can first request a temporary local number (TLDN) from the WLAN base station when it detects a degradation in the quality of the connection with the WLAN, thereby handing-over (hand-over) the call with the third party from the WLAN to the WWAN. When the connection fails, e.g., the mobile phone moves out of range, the mobile phone uses the TLDN to request placement of the call via the WWAN. Upon identifying the TLDN, the request is routed to the WLAN base station, which connects the incoming call with the third party.

US6804532 discloses a system in which a mobile device monitors the link quality of a wireless connection supporting a call and forwards pre-routing information to a second wireless network in anticipation of a need for a handover, and then requests re-routing of the call through the second wireless network.

Disclosure of Invention

The present invention provides a method for maintaining or reestablishing a communication service that includes a session or VoIP call with a third party and that has been established using a wireless link or connection, such as bluetooth or Wi-Fi. The access points supporting the wireless link are arranged to monitor the quality or connectivity of the wireless connection and to send instructions or request re-routing of the call in response to the wireless connection becoming unreliable or a connection quality parameter (such as signal strength) falling below a predetermined threshold. The communication traffic can then be reconnected using another radio link, such as a GSM connection. The mobile device is arranged to automatically answer an incoming call from the further wireless link (e.g. GSM) and is associated with a third party to continue the call without any party having to redial. This means that if a communication service (e.g., a VoIP call) can no longer be supported by an existing wireless link due to the user moving out of range or a change in propagation environment, then the service or call is re-established using other wireless links that are stronger, have a wider range, or have low interference.

The use of a wireless connection access point to monitor the quality of the wireless connection and generally control the initiation of a handover to a wide area network (e.g. GSM) if necessary reduces the complexity of the mobile device, eliminating the need for the mobile device to have complex software that interworks with corresponding software of various network elements on the network side. This in turn typically requires agreement between the network and the mobile device provider on the appropriate protocol to control the operation of the overall system, which in turn increases the complexity of the mobile device. Furthermore, since there is no negotiation with the mobile device required to perform the handover or re-routing, and thus no indication of whether the mobile device has moved completely out of range, the system may make the wireless connection weaker than in methods that require the mobile device to effect the handover before attempting to issue a re-routing request. This is particularly advantageous in wireless environments where signals can fade rapidly, causing problems for mobile devices attempting to achieve handover, or where signals only fade temporarily without having to trigger handover.

In one embodiment, the mobile phone initiates a VoIP call with a third party using a bluetooth wireless link to an access point coupled to a VoIP server via the internet. When the user moves out of range of the access point, the access point detects this and sends a request to the VoIP server to re-route the call onto the mobile phone using the GSM phone number of the mobile phone. In response to identifying the appropriate third party identification code (e.g., third party calling line id (cli)), the mobile telephone receives the call and automatically accepts the call.

Typical real-time communication services may be packet-based calls such as VoIP or video calls, although other communication services may alternatively be provided, such as bursty data connections for maintaining mail or web browsing connectivity.

In one aspect, a method for re-routing a call between a user device and a third party device is provided and includes establishing a call, such as a VoIP call, with the third party device using a first wireless connection, such as a bluetooth connection between the user device and an access point. The access point monitors a quality parameter of the first wireless connection, such as BER, for the duration of the call. The determination of whether a call is in progress may use control messages sent from the user device to the access point or monitoring SIP packets sent from or received by the user device, e.g., indicating that a VoIP call is being established or in progress, by the access point. The call is then automatically rerouted from the third party device to the user device over the second wireless connection between the user device and the base station in response to determining that the quality parameter of the first wireless connection has decreased to a predetermined threshold (e.g., indicating that the user device has moved out of range of the access node employing the first wireless connection). The rerouting of the call may be accomplished by a rerouting request sent by the access point upon determining that the user device has moved out of range. The re-routing request is sent to a network entity, such as a VoIP server or media gateway, where the server application indicates the re-routing required for the call in response to instructions received from the access point.

In one embodiment, the re-routing uses a re-routing number or identifier associated with the user device and the second wireless connection, such as the user device GSM telephone number. The re-routing number may be included in the re-routing request provided by the user device to the access point, and the number may be mapped by the access point of the network entity, such as a VoIP server, from an identifier, such as a Skype VoIP identity associated with the first wireless connection of the user device.

There is also provided a system for re-routing a call between a user device and a third party device, the system comprising:

an access point connected to a user device using a first wireless link;

a network connected to the access point, a third party device, and a base station connected to the user device using a second wireless connection;

the access point is arranged to monitor a first wireless connection quality parameter during a call between the user device and a third party over a first wireless connection via the network;

the system is arranged to automatically re-route the call from the third party to the user device over the second wireless connection between the user device and the base station in response to determining that the quality parameter of the first wireless connection has decreased to a predetermined threshold.

There is also provided a method for operating a user device, the method comprising connecting to an access point using a first wireless connection, connecting to a base station using a second wireless connection, automatically receiving a call over the second wireless connection while making a call with a third party device over the first wireless connection, and automatically receiving the call over the second wireless connection in response to receiving a call setup request associated with the third party device over the second wireless connection.

There is also provided a method of operating an access point by a user, the method comprising connecting to a user device using a wireless connection, connecting to a network for providing a communication path between the user device and the network, monitoring a quality parameter of the wireless connection, and in response to detecting that the quality parameter falls below a threshold, sending a call re-routing request associated with the electronic device to the network.

Drawings

Embodiments will now be described, by way of example and without any limiting purpose, with reference to the following drawings, in which:

FIG. 1 depicts a high-level schematic block diagram of a communication system in accordance with an embodiment;

FIG. 2 depicts a flow diagram of a method of operating an electronic device in accordance with an embodiment;

fig. 3 depicts a flow diagram of a method of operating an access point in accordance with an embodiment;

FIG. 4 depicts a flowchart of a method of operating a call re-routing server in accordance with an embodiment; and

fig. 5 depicts a signaling diagram in accordance with an embodiment.

Detailed Description

Fig. 1 shows a wireless communication system that can be used to support real-time communication services, such as wireless telephony or video conferencing. The wireless communication system 100 includes a mobile phone 110 or other portable electronic device, an access point 120, a VoIP server or network 130, a PSTN network or voice server 140, a third party device 150, and a GSM network 160. The electronic device 110 may be wirelessly connected to the access point 120 using short-range wireless technology or a link 116, such as bluetooth or Wi-Fi. The access point 120 may be connected to a VoIP server 130 using, for example, a broadband internet link 126. The PSTN network server 140 is connected to the VoIP server 130 and the GSM network server using suitable links as is known. The PSTN network 140 is connected to third party devices 150, such as fixed line telephones, using PSTN links 143.

The mobile electronic device 110 includes a mobile device client 113, typically implemented by a software module executing on a processor of the device, and operating in accordance with the method of fig. 2. Similarly, the access point 120 includes an access point protocol station 122, the protocol station 122 supporting a communication link between the electronic device 110 and the VoIP server 130, such as transmitting VoIP packets between the bluetooth wireless link 116 and the ASDL link 126. The access point client 124 operates in accordance with the method of fig. 3 and includes the ability to monitor the quality of the wireless link 116, in some embodiments with the ability to intercept or monitor packets passing through the access point protocol station 122 in order to identify certain types of packets. In particular, the access point client 124 may be configured to identify and interpret Session Initiation Protocol (SIP) packets used to control VoIP calls. The re-routing server application 133 is typically associated with the VoIP server 130, but it may also be located at other parts of the network side (130, 140, 160) of the system 100. The re-routing server application 133 receives a request from the access point client 124 to re-route the VoIP call between the mobile device 110 and the third party device 150 through the GSM network 150 rather than through the access point 120. A method of operating the server 133 will be described in detail with reference to fig. 4.

FIG. 2 illustrates a method of operating the mobile device 110 according to one embodiment. The method (200) first establishes a VoIP call between the mobile device 110 and the third party 150 (205). The VoIP call is first established over a "short-range" wireless link 116 with the access point 120 (if the link does not already exist) and then implemented using the broadband internet connection of the access point. VoIP call setup is accomplished through the use of SIP messages, as is well known to those skilled in the art, which are sent to VoIP via wireless link 116A network 130. Typically, the mobile device 110 sends a SIP invite message to the VoIP server 130, the message including, for example, its Skype phone number or Calling Line Identification (CLI)₁) And also the identity of a third party device (CLI), typically such as a third party telephone number₃). This information is used by the VoIP server to call the third party 150 to complete the VoIP call. This will be described in detail with reference to fig. 4.

Once the VoIP call is established, the method optionally sends a control message to the access point client 124 instructing that re-routing of the current call be performed if the wireless connection 113 fails (210). The message may also include a re-routing number (CLI) such as the GSM number of the mobile device₂). Alternatively, the access point may automatically detect the establishment of a VoIP call by, for example, intercepting related SIP packets. This reduces the workload and complexity of the mobile device 110. The method then uses the telephone number (CLI)₃) Or other suitable third party identification code, sets an automatic answer feature on the mobile device (210). This auto-answer feature is included on most new mobile phones and when set automatically answers GSM or other long-range or cellular (e.g., CDMA, UMTS) wireless incoming calls. However, the automatic answer is set to only incoming calls from the third party 150 (CLI)₃) Answering or responding to special identification Codes (CLI)_special) The answer is made while no answer is made to any other incoming call with a different calling line identification Code (CLI). The user of the mobile device 110 continues the VoIP call with the third party using the short range WLAN or PAN (personal area network) wireless link 116.

The mobile device 110 does not make a determination as to whether it is out of range of the access point 120, which is performed without involvement of the mobile device 110. As a result of the mobile device moving out of range, however, the access point issues an instruction to reroute the VoIP call to be routed to the mobile device 110 through the cellular GSM network 160. Thus, in a next step (220), the method automatically answers the incoming GSM call on the GSM connection 163 from the GSM base station (shown generally as GSM network 160),wherein the incoming call is associated with a third party caller line identification Code (CLI)₃) And (4) correlating. The identification code is typically sent as part of a known call setup process. The VoIP call then continues via a GSM or long-range wireless connection 163 with the mobile device 110. The method then ends the VoIP call via the short-range wireless link that is now no longer supported (225). Thus, despite the brief pause in the VoIP call, the user of the mobile device does not need to re-dial the third party when moving out of range of the access point, but rather the "replacement" call is automatically received from the base station (160) providing the second wireless connection to the mobile device 110. Optionally, this may be accompanied by informing the user of the situation through a predetermined voice message.

Fig. 3 illustrates a method of operating the access point 120 in accordance with one embodiment. The method (300) first detects a VoIP call setup from a mobile device (305). This detection may be accomplished by detecting SIP packet traffic (traffic) from the mobile device, since the SIP packets indicate the establishment of a VoIP call, which may be established through the mobile device 110 or a third party device 150 calling the mobile device user. Specific information can be recovered from these SIP packets, including the called third party's identification Code (CLI)₃) And identification Code (CLI) of mobile device₁)(310). These identifiers may be used to re-route the call at a later time. In an alternative configuration, a message may be sent from mobile device 110 to access point 120(210) informing the mobile device that a VoIP call is being established, and the message may include a third party (CLI)₃) And/or re-routing number (CLI)₂Such as a mobile device GSM telephone number).

The method then monitors a short range (e.g., bluetooth) wireless link 116(215) between the mobile device 110 and the access point 120. This may be accomplished in a number of ways, such as by recording the signal strength or BER of the well-known link 116. The method then checks whether the quality parameter or combination of quality parameters falls below a predetermined threshold, indicating that the mobile device 110 has moved out of range (320). If notIf so (320N), then the method continues to monitor link quality. However, if the link quality indicates that the mobile station has moved out of range (320Y), the method sends a special re-routing instruction (325). The instruction is sent to the re-routing server application 133, the server application 133 typically residing on the VoIP server 130, and the instruction is typically a SIP "path no longer valid" type message. The re-routing instructions can be configured to include a recovered third party identification Code (CLI)₃) A GSM identification or rerouting number (CLI) associated with the mobile device 110₂) Or an identification Code (CLI) associated with a mobile device calling number or called number of an original VoIP call via an access point₁). The rerouting number (CLI)₂) May be initially transmitted from the mobile device 110 to the access point (210) and used by the access point or the rerouted call server 133 to initiate a VoIP call number (CLI) from the mobile device using a suitable database₁) And is mapped out. A mapping database 134 of subscriber identities CLI1 to re-routing numbers or identities CLI2 is indicated in fig. 1 as being coupled to a re-routing server application 133 residing on top of the VoIP network or server 130. However, these entities may be distributed in any reasonable manner as will be apparent to those skilled in the art. The re-routing message from the access point 120 to the re-routing server application 133 causes the VoIP call to be re-routed via the cellular or GSM network 160, as will be described in more detail with reference to fig. 4 below. The method is then configured to close the wireless session or link 116 between the mobile device and the access point (330).

Fig. 4 depicts a method (400) of operating a re-routing server application 133 that is typically integrated into the VoIP server 130 and may form part of an updated VoIP routing protocol. Alternatively, the server application 133 may be associated with the PSTN140 or cellular 160 networks. Initially, a VoIP call is established by the VoIP network or server 130 using well known SIP messages (405). SIP messages are used to establish the various segments of the call between the mobile device 110 and the VoIP server 130, and between the third party device 150 and the VoIP server 130. Once the two segments are establishedThe VoIP server 130 connects the two legs and the call can be placed. Once the VoIP call is established, the method waits for a re-routing message (410). The re-routing message may include an identification Code (CLI) of the third party₃) But alternatively the method may simply recover this information from the VoIP server that used it to direct the initial call setup. The message may also include a re-routing number (CLI 2). If the re-routing number is not included in the re-routing message, the method will re-route the mobile identity (CLI) in the message or in the original VoIP call setup₁) Mapping to a land line, GSM number or user name or number (CLI) such as Skype associated with a mobile phone or subscriber to an identification code₂) Other numbers (415). The mapping may be contained in a database 134 associated with the re-routing server application 133, in which case the users would need to register their re-routing numbers with the re-routing service (133). Where the number to reroute the call is provided by the access point, which may be programmed into the access point by the user.

The method then sends a voice message to the third party (420), such as a pre-recorded message informing the third party that the current call is being redirected. The method then commands the VoIP network to use the re-routing message or a re-routing number (CLI) in a mapping database₂) A new VoIP call is established (425). As previously discussed, in this embodiment, the rerouting number (CLI)₂) Associated with the GSM telephone number of electronic device 110. The VoIP call setup is performed in a standard manner, with the call setup message for the segment to the mobile device containing a third party identification Code (CLI)₃). Alternatively, a special application identification Code (CLI) associated with the application may be used_special). The call setup procedure causes the user's mobile device 110 to automatically answer the incoming GSM call as previously described. When a new VoIP call is established, the method connects (430) the newly established VoIP segment to the mobile device with the existing VoIP segment to the third party through the GSM base station so that the original VoIP call can be restored. In an alternative arrangement, the method may be carried out by well-known meansThe appropriate control instructions authorize the call setup and connection functions to another network entity, such as a PSTN network server (435).

Fig. 5 shows the signaling between the various entities of the system. User 501 commands device client 113 to establish a VoIP call (505). Alternatively, the VoIP call may be established without the mobile device client, however depending on the system configuration, if the user moves out of range, this may not be automatically rerouted. If a short-range wireless connection is not established with the access point 120, the connection is made and the appropriate VoIP client of the device 110 requests the VoIP network 130 to establish a call to the third party telephone 150 (510). The VoIP network establishes a VoIP path between user device 110 and the VoIP network (515). The VoIP network 130 then sends a ring tone to the third party VoIP capable phone using SIP messaging over, for example, the PSTN network (520). The ringing tone reaches the third party user or called party (525) and when the third party user or called party answers the phone 150 (530), further SIP messages are exchanged between the third party phone 150 and the VoIP network 130 to establish a VoIP path between the aforementioned well-known entities (535). The VoIP network 130 then connects these paths together to form the call (540).

The access point 124 monitors the VoIP link (545) and sends a re-routing message to the re-routing server application 133(550) upon detecting that the mobile device is out of range. The re-routing server, in turn, instructs the VoIP network to tear down the call between the VoIP network and the client device 110 (555) and sends a voice message to the third party via the remaining call leg (560). The VoIP network is then established to the Mobile device GSM number (CLI)₂) Is received, this is automatically answered by the mobile device client, and a VoIP call via a GSM connection is established (570). The VoIP network then connects the call with the mobile device 110 and the call with the third party 150 to establish an alternative route for the original VoIP call via the GSM network 160 (575).

Thus if the user moves out of range of an access point using a short range wireless connection such as a bluetooth association, the VoIP call is automatically rerouted to the mobile device via its own GSM or other cellular connection without either party having to redial the other.

Although described with respect to an embodiment that reroutes a VoIP call from a bluetooth or Wi-Fi wireless connection to a cellular (e.g., GSM, CDMA, UMTS) connection, the rerouting may involve any two networks that perform rerouting advertisements on the network side, such as rerouting between bluetooth and Wi-Fi networks. Similarly, communication sessions other than VoIP calls may be supported, such as mail connections, circuit switched calls, video calls.

Those skilled in the art will recognize that the apparatus and methods described above may be implemented as processor control code, for example, on a carrier medium such as a hard disk, CD or DVD-ROM, programmable memory such as read only memory (firmware), or on a data carrier such as an optical or electrical signal carrier. Various embodiments of the invention will be implemented on a DSP (digital signal processor), an ASIC (application specific integrated circuit), or an FPGA (field programmable gate array). The code may thus comprise conventional programming code or microcode, for example to set up or control an ASIC or FPGA. The code may also include code for dynamically configuring a reconfigurable device, such as a reprogrammable array of logic gates. Similarly, the code may include code for a hardware description language, such as Verilog^TMOr VHDL (very high speed integrated circuit hardware description language). As will be appreciated by those skilled in the art, the code may be distributed among a plurality of connected components in communication with each other. Suitably, the embodiments may also be implemented using code running on a field-programmable (re-) programmable simulation array or similar device to configure simulation hardware.

It will be appreciated by those skilled in the art that the various embodiments described above and the specific features described for those embodiments can be freely combined with other embodiments or the specifically described features of those other embodiments in accordance with the above teachings. It should also be appreciated by those skilled in the art that various modifications and substitutions can be made to the specific examples described without departing from the spirit and scope of the appended claims.

Claims (8)

1. A method for re-routing a call between a user device and a third party device, the method comprising:

establishing a call with the third party device using a first wireless connection between the user device and an access point;

monitoring, at the access point, a quality parameter of the first wireless connection;

automatically forwarding, at the access point, a re-routing message from the access point to a communication network entity instructing re-routing of the call to a base station to re-route the call from the third party device to the user device over a second wireless connection between the user device and the base station in response to determining that the quality parameter of the first wireless connection has fallen below a predetermined threshold.

2. The method of claim 1, wherein the monitoring a quality parameter of the first wireless connection is performed in response to the access point determining that the call has been established.

3. The method of claim 2, wherein the determination of the call setup comprises: call setup packets communicated between the user device and the communication network entity are identified.

4. The method according to any one of the preceding claims, further comprising: mapping an identifier associated with the first wireless connection to an identifier associated with the second wireless connection to reroute the call using the second wireless connection identifier.

5. The method of any of claims 1-3, wherein the first wireless connection is a bluetooth or Wi-Fi connection, the second wireless connection is a cellular wireless connection, and the call is a voice over internet protocol call.

6. An access point, comprising:

a transceiver for providing a first wireless connection with an electronic device;

means for connecting to a network for providing a communication path between the electronic device and the network;

means for monitoring a quality parameter of the first wireless connection in response to determining that a call has been established between the electronic device and a third party device using the communication path;

means for sending a re-routing message from the access point to a communication network entity instructing re-routing of the call to a base station to re-route the call from the third party device to the electronic device over a second wireless connection between the electronic device and the base station in response to determining that the quality parameter of the first wireless connection has fallen below a predetermined threshold,

wherein the electronic device comprises a first transceiver for providing the first wireless connection with the access point and a second transceiver for providing the second wireless connection with the base station.

7. The access point according to claim 6, wherein the quality parameter comprises a bit error rate level, and/or a signal strength indicator.

8. An access point according to claim 6 or 7, wherein the determination that a call is established is made by detecting SIP packets on the communication path.