WIRELESS COMMUNICATION SYSTEM

Abstract

Methods and apparatus for communicating circuit switched voice data with a first cellular radio access network (RAN) and communicating voice over Internet protocol (VoIP) packets using session initiation protocol (SIP) with a second cellular RAN. The second cellular RAN does not support circuit switched voice communication.

Claims

1. A user equipment comprising: a receiver, a transmitter, and a processor, wherein the receiver, the transmitter, and the processor are configured to cause the user equipment: to communicate circuit switched voice data with a first cellular radio access network (RAN); and to communicate voice over Internet protocol (VoIP) packets using session initiation protocol (SIP) with a second cellular RAN, wherein the second cellular RAN does not support circuit switched voice communication.

2. The user equipment of claim 1 wherein the second cellular radio access network is IP based.

3. The user equipment of claim 1 wherein the receiver, the transmitter, and the processor are configured to cause the user equipment to use an AMR type codec to produce voice data and to process the produced voice data to produce the VoIP packets.

4. The user equipment of claim 1 wherein the receiver, the transmitter, and the processor are configured to cause the user equipment to process VoIP packets and to use an AMR type codec to recover a voice signal.

5. The user equipment of claim 1 wherein the receiver, the transmitter, and the processor are configured to cause the user equipment to send the VoIP packets to an IP gateway associated with the second radio access network.

6. A method comprising: communicating, by a user equipment, circuit switched voice data with a first cellular radio access network (RAN); and communicating, by the user equipment, voice over Internet protocol (VoIP) packets using session initiation protocol (SIP) with a second cellular RAN, wherein the second cellular RAN does not support circuit switched voice communication.

7. The method of claim 6 wherein the second cellular RAN is IP based.

8. The method of claim 6 comprising using an AMR type codec to produce voice data and processing the produced voice data to produce the VoIP packets.

9. The method of claim 6 comprising processing VoIP packets and using an AMR type codec to recover a voice signal.

10. The method of claim 6 wherein comprising sending, by the user equipment, the VoIP packets to an IP gateway associated with the second radio access network.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] FIG. 1 is a graphic illustration of a conventional UMTS network in accordance with current 3GPP specification.

[0043] FIG. 2 is a block diagram showing various components and interfaces of the network illustrated in FIG. 1.

[0044] FIG. 3 is a schematic diagram of the conventional network illustrated in FIGS. 1 and 2 indicating layered stacked protocols of the various component interfaces in both signaling and user data planes.

[0045] FIG. 4 is a graphic illustration of a UMTS network including a RLAN with a direct Internet link in accordance with the teachings of the present invention.

[0046] FIG. 5 is a block diagram showing various components of the network shown in FIG. 4.

[0047] FIG. 6 is a block diagram showing a variation of the network where the RLAN has no direct connection with the UMTS Core Network.

[0048] FIG. 7 is a schematic illustration of signaling data flow in the UMTS network illustrated in FIG. 6.

[0049] FIG. 8 is a graphic illustration of a second variation of the UMTS network illustrated in FIG. 4 wherein the RLAN has a first type of limited connection with the UMTS Core Network.

[0050] FIG. 9 is a graphic illustration of a second variation of the UMTS network illustrated in FIG. 4 wherein the RLAN has a second type of limited connection with the UMTS Core Network.

[0051] FIGS. 10A and 10B illustrate two variations of IP packet data flow for the networks shown in FIGS. 4, 8 and 9 wherein Mobile IP v4 protocol is implemented by the RLAN.

[0052] FIGS. 11A and 11B illustrate two variations of IP packet data flow for the networks shown in FIGS. 4, 8 and 9 wherein Mobile IP v6 protocol is implemented by the RLAN.

[0053] FIG. 12 is a schematic illustration of preferred signaling plane and user plane interfaces within a RLAN made in accordance with the teachings of the present invention.

[0054] FIG. 13 is a schematic illustration of a RLAN having a single Radio Network Controller in accordance with the teachings of the present invention.

[0055] FIG. 14 is a schematic illustration of a RLAN having multiple Radio Network Controllers made in accordance with the teachings of the present invention.

[0056] FIG. 15 is an illustrated diagram of an alternate configuration of an RLAN having separate servers for user data and control signals and also an optional voice gateway made in accordance with the teachings of the present invention.

[0057] FIG. 16 is a block diagram of components of the RLAN illustrated in FIG. 15.

[0058] FIG. 17 is a schematic diagram illustrating a preferred protocol stack for the control plane interfaces of a RLAN made in accordance with the teachings of the present invention.

[0059] FIG. 18 is a schematic diagram illustrating a preferred protocol stack for the user plane interfaces of a RLAN made in accordance with the teachings of the present invention.

[0060] FIGS. 19, 20 and 21 are schematic diagrams illustrating three variations of interface protocol stacks in the user plane for supporting voice communication between a UE having a wireless connection with an RLAN and an ISP connected to the RLAN which has a voice gateway.

[0061] FIG. 22 is a schematic diagram illustrating a variation of interface protocol stacks in the control plane for supporting voice communication between a UE having a wireless connection with an RLAN and an ISP connected to the RLAN which has a voice gateway.

TABLE-US-00001 TABLE OF ACRONYMS 2G Second Generation 2.5G Second Generation Revision 3GPP Third Generation Partnership Project AAA functions Authentication, Authorization and Accounting functions AAL2 ATM Adaptation Layer Type 2 AAL5 ATM Adaptation Layer Type 5 AMR A type of voice data compression ATM Asynchronous Transfer Mode CDMA Code Division Multiple Access CN Core Network CODECs Coder/Decoders C-RNSs Control Radio Network Subsystems CS Circuit Switched ETSI European Telecommunications Standard Institute ETSI SMG ETSI - Special Mobile Group FA Forwarding Address FN Foreign Network G.729 A type of voice data compression GGSN Gateway GPRS Support Node GMM GPRS Mobility Management GMSC Gateway Mobile Switching Center GPRS General Packet Radio Service GSM Global System for Mobile Telecommunications GTP GPRS Tunneling Protocol GW Gateway H.323/SIP H.323 Format for a Session Initiated Protocol HLR Home Location Register HN Home Network HSS Home Service Server IP Internet Protocol ISDN Integrated Services Digital Network ISP Internet Service Provider Iu-CS Iu sub Interface for Circuit Switched service Iu-PS Iu sub Interface for Packet Switched service IWU Inter Working Unit M3UA Message Transfer Part Level 3 SCCP SS7 Adaptation Layer MAC Medium Access Control MAP Mobile Application Part MSC Mobile Switching Centre NRT Non-Real Time PCM Pulse Code Modulation PLMN Public Land Mobile Network PS Packet Switched PSTN Public Switch Telephone Network RANAP Radio Access Network Application Part RAN IP Radio Access Network Internet Protocol RIP GW RAN IP Gateway RLAN Radio Local Area Network RLC Radio Link Control RNC Radio Network Controller RRC Radio Resource Control RT Real Time SCCP/MTP Signaling Connection Control Part, Message Transfer Part SGSN Serving GPRS Support Node SCTP Stream Control Transmission Protocol SM Session Management SMS Short Message Service S-RNS Serving Radio Network Subsystems SS7 Signaling System 7 SSCF Service Specific Coordination Function SSCOP Service Specific Connection Oriented Protocol TDD Time Division Duplex UDP/IP User Data Protocol for the Internet Protocol UE User Equipment UMTS Universal Mobile Telecommunications System UTRAN UMTS Terrestrial Radio Access Network VLR Visitor Location Register

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0062] With reference to FIG. 4, there is shown a modified Universal Mobile Terrestrial System (UMTS) network having a Radio Local Area Network (RLAN) with a direct Internet connection. As shown in FIG. 5, the RLAN employs base stations to communicate via a wireless radio interface with the various types of User Equipments (UEs). Preferably the base stations are of the type specified in 3GPP as node Bs. A radio controller is coupled to the base stations to control the wireless interface. Preferably the radio controller is a Radio Network Controller (RNC) made in accordance with 3GPP specification. Various combinations of Node Bs and RNCs may be employed as used in a conventional 3GPP UTRAN. Collectively, the geographic ranges of the wireless communications conducted with the base stations of the RLAN defines the RLAN's service coverage area.

[0063] Unlike a conventional UTRAN, the RLAN of the present invention includes a Radio Access Network Internet Protocol (RAN IP) gateway which provides connectivity for the RLAN outside its service coverage area, i.e. the geographic area served by the wireless communication with its base stations. As illustrated in FIGS. 4 and 5, the RAN IP gateway has a direct Internet connection and may have the standard direct UMTS network connection through an Iu interface with an associated Core Network. Alternatively, as illustrated in FIG. 6, the direct interface between an associated Core Network and the RAN IP gateway may be omitted so that the RAN IP Gateway can have only a direct connection with the Internet. In such case, as illustrated in FIG. 7, the RLAN of the present invention may still form a part of a UMTS by the tunneling of control and AAA function information to a Core Network which serves as its Home CN.

[0064] FIGS. 8 and 9 illustrate two separate versions of an RLAN made in accordance with the teachings of the present invention wherein the RAN IP Gateway is configured with a control signal port for establishing a limited direct connection with its Home UMTS Core Network. In particular, the limited connectivity transports information needed to provide AAA function support for the CN.

[0065] The RAN IP Gateway control signal port may be configured, as illustrated in FIG. 8, to provide control signal data using radius/diameter based access in which case the core network includes an Inter Working Unit (IWU) as specified in 3GPP which converts AAA function information into conventional Mobile Application Part (MAP) signaling for connection with the HSS/HLR of the Core Network. Alternatively, as illustrated in FIG. 9, the RAN IP Gateway control signal port can be configured as a subset of a standard Gr interface which supports MAP signaling which can be directly used by the HSS/HLR of the CN.

[0066] Preferably, the RAN IP Gateway employs a standard GI interface with the Internet and can be utilized as a stand-alone system without any association with a Core Network of a UMTS. However, in order to support mobility management with roaming and hand-over services available for subscriber UEs of the RLAN, an AAA function connection with a Core Network, such as by way of the various alternatives illustrated in FIGS. 7, 8 and 9, is desirable. In such case, in addition to a standard GI interface between the RAN IP Gateway of the RLAN and the Internet, a mobile IP protocol is supported. Preferred examples of such mobile IP protocols are the Mobile IP v4 protocol and the Mobile IP v6 protocol as specified by IETF.

[0067] FIG. 10 illustrates IP packet data flow for a communication between a first UE having a wireless connection with the RLAN and a second UE outside the wireless service region of the RLAN where Mobile IP v4 is implemented on the GI interface between the RAN IP Gateway and the Internet. In such case, user data from the first UE is sent in IP packet format from the RAN IP Gateway of the RLAN through the Internet to the address provided by the second UE. The second UE communications are directed to the Home Address of the first UE which is maintained at the Core Network since in this example the first UE has the CN as its Home CN. The CN receives the IP data packets from the second UE and then the CN forwards the IP packets to the current location of the first UE which is maintained in the CN's HLR as the Forwarding Address (FA) of the first UE.

[0068] In this example, since the first UE is home, the CN tunnels the IP Packets through the Internet to the RAN IP gateway for communication to the first UE. In the case of the first UE traveling outside of the RLAN, its location will be registered with the Core Network and the data packets directed to the address where the first UE is currently located be used by the core network to direct the IP packet data to the current location of the first UE.

[0069] FIG. 10B illustrates an alternate approach where Mobile IP v4 is implemented on the GI interface using with reverse path tunneling such that the RLAN directs the IP packets of the first UE's user data to the Home CN where they are relayed to the second UE in a conventional manner.

[0070] When the RLAN has connectivity using a GI interface that implements Mobile IP v6, the IP packet data exchange between the first UE and the second UE will contain binding updates, as illustrated in FIG. 11A, which will reflect any redirection of the IP packets needed for hand-over. FIG. 11B illustrates an alternative approach using a GI interface implementing mobile IP v6 that includes tunneling between the RLAN and the Home CN. In such case, the CN directly tracks location information of the first UE and the second UE may communicate with the first UE's Home CN in any type of conventional manner.

[0071] With reference to FIG. 12, there is shown the construction of preferred interfaces between the components of the RLAN of the present invention. The UE interface between the RLAN via the base station, Node B, is preferably a standard Uu interface for connection with UEs as specified by 3GPP. An Iub interface between each Node B and RNC is preferably implemented both in the control plane and the user data plane as a layered stacked protocol having Internet Protocol (IP) as the transport layer. Similarly at least a subset of an Iu-PS interface is preferably provided between an RNC and the RAN IP Gateway that is a layered stacked protocol having IP as the transport layer.

[0072] In a conventional UMTS where SS7 is implemented over ATM, the MTP3/SSCF/SSCOP layers help SCCP, which is the top layer of the SS7 stack, to plug onto an underlying ATM stack. In the preferred IP approach used in conjunction with the present invention, the M3UA/SCTP stack helps SCCP connect onto IP. Essentially, the M3UA/SCTP stack in the preferred IP-based configuration replaces the MTP3/SSCF/SSCOP layers that are used in the conventional SS7-over-ATM approach. The specific details of these standard protocol stack architecture are defined in the IETF (Internet) standards. The use of IP in lieu of ATS enables cost-savings as well as PICO cells for office and campus departments.

[0073] Where the RLAN has multiple RNCs, the RNCs can be interfaced via an Iur interface having layered stacked protocols for both the signaling plane and user plane using an IP transport layer. Each RNC is connected to one or more Node Bs which in turn serve in plurality of UEs within respective geographic areas that may overlap to enable intra-RLAN service region handover.

[0074] Handover of a UE communication with one Node B within the RLAN to another Node B within the RLAN, intra-RLAN handover, is conducted in the conventional manner specified in 3GPP for intra-UTRAN handover. However, when a UE communicating with a Node B of the RLAN moves outside the RLAN service region, handover is implemented via the RAN IP gateway utilizing IP packet service, preferably, implemented with Mobile IP v4 or Mobile IP v6 as discussed above.

[0075] FIG. 13 illustrates the subcomponents of a preferred RLAN in accordance with the present invention. The RNC can be divided into standard Control and Serving Radio Network Subsystems (C-RNSs and S-RNSs) connected by an internal Iur interface. In such a configuration, the S-RNS functions are coupled to a SGSN subcomponent of the RAN IP gateway which supports a subset of the standard SGSN functions, namely, GPRS Mobility Management (GMM), Session Management (SM) and Short Message Service (SMS). The SGSN subcomponent interfaces with a GGSN subcomponent having a subset of a standard GGSN functions including an access router and gateway functions support for the SGNS subcomponent functions and a GI interface with mobile IP for external connectivity to the Internet. The SGSN subcomponent interface with the GGSN subcomponent is preferably via modified Gn/Gp interface, being a subset of the standard Gn/Gp interface for a CN's SGNS and GGSN.

[0076] Optionally, the RAN IP Gateway has an AAA function communication subcomponent that is also connected to the SGSN subcomponent and provides a port for limited external connectivity to an associated CN. The port supporting either a Gr interface or a Radius/Diameter interface as discussed above in connection with FIGS. 8 and 9.

[0077] Multiple RNCs of the RLAN can be provided coupled with the SGSN subcomponent by an Iu-PS interface which includes sufficient connectivity to support the functions of the SGSN subcomponent. Where multiple RNCs are provided, they are preferably coupled by a standard Iur interface which utilizes an IP transport layer.

[0078] The use of IP for the transport layer of the various components of the RLAN readily lends itself to implementing the RNC functions in separate computer servers to independently process the user data of communications and the signaling as illustrated in FIG. 15. Referring to FIG. 16, there is a component diagram where the radio control means is divided between U-plane and C-plane servers. In addition to the basic RLAN components, an optional Voice Gateway is also illustrated in FIGS. 15 and 16.

[0079] Each Node B of the RLAN has a connection using an IP transport layer with a U-plane server which transports user data. Each Node B of the RLAN also has a separate connection with a C-plane server via a standard Iub signal control interface having an IP transport layer. Both the U-plane server and C-plane server are connected to the IP gateway using layered stacked protocols, preferably having IP as the transport layer.

[0080] For multiple C-plane server configurations, each can be coupled to each other via a standard Iur interface, but only one is required to be directly connected to the RIP GW. This allows the sharing of resources for control signal processing which is useful when one area of the RLAN becomes much busier in other areas to spread out the signal processing between C-plane servers. A plurality of C-plane and U-plane servers can be connected in a mesh network for sharing both C-plane and U-plane resources via stacked layer protocols preferably having an IP transport layer.

[0081] Where the optional voice gateway having external connectivity via PCM circuit is provided, the U-plane server and C-plane server are coupled to the voice gateway via a stacked layer protocols preferably having an IP transport layer. The C-plane server is then coupled to the U-plane server via a Media gateway control protocol gateway (Megaco) over an IP transport layer. Megaco is a control plane protocol that sets up the bearer connection(s) between a Voice gateway elements, as part of call establishment.

[0082] Referring to FIGS. 17 and 18, there are shown, respectively, preferred C-plane and U-plane protocol stacks which are implemented between the Node Bs, RNCs (or U- and C-plane servers) and the RAN IP Gateway of the RLAN. In each drawing, the preferred over air protocol stack implemented via the Uu interface with UEs is also shown.

[0083] The RLAN can be configured with voice support over its external IP connection. In such case, the RIP gateway is connected with an Internet Service Provider (ISP) which in turn has a PCM voice gateway. The PCM voice gateway converts voice compression data into a Pulse Code Modulation (PCM) format for external voice communications.

[0084] Vocoders are provided that use Coder/Decoders (CODECs) for compression of voice data. Two common types vocoder formats are the AMR vocoder format and G.729 compression format. FIGS. 19 and 21 show preferred U-plane protocol stacks which are implemented where the voice gateway of the ISP to which the RLAN is connected uses the same type of voice compression interface as the UE. AMR vocoder format being illustrated in FIG. 19; G.729 vocoder format being illustrated in FIG. 21. The voice over IP is simply transferred as regular packet data over the IP interface without change.

[0085] Where the UE utilizes a different voice compression protocol than the voice gateway of the ISP, a converter is provided in the RNC or the RAN IP Gateway. FIG. 20 shows preferred U-plane protocol stacks, where the UE utilizes an AMR vocoder and the ISP voice gateway utilizes a G.729 vocoder. Preferably, the RAN IP Gateway (RIP GW) includes the AMR/G.729 converter. In the case illustrated in FIG. 20, the converter converts AMR compressed data received from the node B to G.729 format compressed voice format for output by the RIP GW. Where the RLAN utilizes separate U-plane and C-plane servers, the compressed voice data is transported by a U-plane server and the converters may be located in either the U-plane servers or the IP gateway.

[0086] With reference from FIGS. 22, there is shown preferred control plane protocol stack architecture for supporting voice using standard 11.323 format for a Session Initiated Protocol (11.323/SIP) over TCP/UDP carry by IP. The control signaling is essentially the same irrespective of the type of voice data compression conducted in the U-Place.

[0087] Although the present invention has been described based on particular configurations, other variations will be apparent to those of ordinary skill in the art and are within the scope of the present invention.