Abstract:
Methods and network nodes are described. A network node receives an attach request message from a wireless transmit/receive unit (WTRU) via a cellular radio access network (RAN). The attach request message includes a mobile station (MS) radio access capability information element (IE), and the MS radio access capability IE includes a field that indicates whether the WTRU is capable of receiving services from a core network via a non-cellular wireless access network. The network node provides services from the core network to the WTRU.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of application Ser. No. 13/285,746, filed Oct. 31, 2011, which is a continuation of application Ser. No. 11/083,125, filed Mar. 17, 2005, which issued as U.S. Pat. No. 8,102,823 on Jan. 24, 2012, which is a continuation of application Ser. No. 10/750,193, filed Dec. 31, 2003, which issued as U.S. Pat. No. 6,940,844 on Sep. 6, 2005, which claims the benefit of U.S. Provisional Application No. 60/512,164, filed on Oct. 17, 2003, the contents of which are hereby incorporated by reference herein. 
    
    
     FIELD OF INVENTION 
     The present invention relates to WTRUs having dual-mode capabilities and more particularly to method and apparatus for reporting dual mode capabilities and for reporting availability of network interworking. 
     BACKGROUND 
     The current developments of wireless local area network (WLAN) interworking with general packet radio service/universal mobile telecommunications system/third generation (GPRS/UMTS/3G) networks has resulted in products that include two radio units in a common enclosure (e.g., cards supporting 802.11b+GPRS air interfaces and 802.11b+UMTS air interfaces). The units may be separate cards or may be integrated onto one common card. 
     Hereafter a wireless transmit/receive unit (WTRU) includes but is not limited to a user equipment, mobile station, fixed or mobile subscriber unit, pager, or any other type of device capable of operating in a wireless environment. When referred to hereafter, a base station includes but is not limited to a Node-B, site controller, access point or any other type of interfacing device in a wireless environment. 
     Currently the network may not be aware of the dual-mode capabilities of the terminal. In addition, the offered services may change dramatically based on the terminal capabilities in terms of processing power, memory availability, screen size, bit rate, etc. For example, a dual mode 802+GPRS personal digital assistant (PDA) may be able to receive short message service (SMS) or multimedia message service (MMS) messages over a GPRS or an 802 network, however, several variations of these services may be provided in accordance with allotted memory space of the wireless terminal. Rich multimedia services may require larger memory size than that available in the PDA. Therefore, the same multimedia services may be provided via black and white or a reduced set of colors depending on terminal capabilities. Also, the possibility of network-assisted handoff can be provided to those terminals that indicate dual mode (WLAN/GPRS or WLAN/3G) capabilities. A mechanism is needed to indicate these capabilities to the existing GPRS/UMTS networks. 
     In addition, in network interworking, there is no capability of informing a wireless terminal having dual-mode radio capabilities and relying upon one of the networks with which it communicates to be advised of the interworking capability to enable the wireless terminal to have the increased ability of communicating with either of the two networks. 
     SUMMARY 
     Methods and network nodes are described. A network node receives an attach request message from a wireless transmit/receive unit (WTRU) via a cellular radio access network (RAN). The attach request message includes a mobile station (MS) radio access capability information element (IE), and the MS radio access capability IE includes a field that indicates whether the WTRU is capable of receiving services from a core network via a non-cellular wireless access network. The network node provides services from the core network to the WTRU. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be understood from a consideration of the figures in which like elements are designated by like numerals and, wherein: 
         FIG. 1  is a simplified schematic diagram of the network having integrated universal mobile telephone service (UMTS) and wireless local area network (WLAN) networks. 
         FIG. 2  is a simplified schematic diagram showing an attached procedure and embodying the capabilities of the present invention. 
         FIG. 3  shows a WTRU network capability information element (IE). 
         FIGS. 4 and 5  respectively show the existing and modified network capability and radio access (RA) capability information element (IE). 
         FIG. 4A  shows the modified network capabilities IE of  FIG. 4  in greater detail. 
       FIGS.  5 A 1 - 5 A 2  and  5 B show the modified RA capability IE of  FIG. 5  in greater detail and  FIG. 5A  shows the manner in which FIGS.  5 A 1  and  5 A 2  are arranged. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The problem solved by this invention is the mechanism by which a terminal that supports both GPRS and WLAN, or 3G and WLAN can report its WLAN capabilities to the supporting GPRS/UMTS networks. Also, the invention identifies the mechanism by which a 3G network can indicate that 3G or packet switched domain services over WLAN are available. 
       FIG. 1  shows a simplified block diagram of a network in which a UMTS and a WLAN are integrated. The WTRUs  12 ,  14  and  16  communicate with the network over respective radio links (RL-1, RL-2 and RL-3). More particularly, WTRU  12  communicates with a GSM radio access network (RAN); WTRU  14  communicates with a 2.5/3G RAN and WTRU  16  communicates with a WLAN access point (AP). WTRUs  12  and  14  may be cellular telephones while WTRU  16  may be a laptop, personal digital assistant (PDA) or other like device having an appropriate card enabling communication with the WLAN AP. 
     The GSM RAN communicates with a mobile switching center (MSC) which, as is known in the art, has the capability of interworking with location data bases. The MSC communicates with the visitor location register (VLR) to identify, authenticate, etc. the WTRU  12 . The MSC also communicates with the short message service-gateway mobile switching center/interworking-mobile switching center (SMS-GMSC/IW-MSC) which provides the services such as short message service (SMS) data. The home location register (HLR) is a data base within the home public land mobile network (HPLMN) providing routing information for mobile terminated calls and SMS data and is also responsible for maintenance of user subscription information distributed to the relevant VLR (note the VLR in  FIG. 1 ) or GSN (GPRS support node) through the attached process and mobility management procedures such as location area and routing area updates. 
     The WLAN AP communicates with a packet data gateway/WLAN access gateway (PDG/WAG). Capability information is exchanged between the GSN and the PDG/WAG. Services such as SMS data services are communicated to the PDG/WAG and hence to the WTRU  16  by way of the PDG/WAG and WLAN AP. Based on the capability of the WTRU  16 , SMS data may be delivered thereto. 
     The WTRUs  12  and  14  when respectively communicating with the network through their associated RAN, provide information regarding their capability which, in accordance with the present invention, includes WLAN compatibility. 
       FIG. 2  shows an attached procedure combined with a WLAN capability update. In the procedure shown in  FIG. 2 , a UMTS dual mode WTRU, at step S 1 , powers up for a signaling connection to perform the ATTACH procedure. At step S 2 , a radio resource control (RRC) connection request message is conveyed to the radio network controller (RNC). Admission control and availability of resources is performed by the RNC, at step S 3 , which then conveys an RRC connection setup message to the dual mode WTRU, at step S 4 . The WTRU, at step S 5 , provides an RRC connection set up complete message providing the WTRU radio access (RA) compatibility and, at step S 6 , provides the initial direct transfer message, which includes the attached request and the point-to-multipoint system information (PtM SI), instant messaging system information (IM SI), network (NW) capability and radio access (RA) capability. The RNC, at step S 7 , provides an initial WTRU Message: attach request including the network and radio access capabilities. In addition to the UMTS capabilities, the message further contains WLAN capability. At step S 8 , authentication and ciphering request and security mode commands are performed and the WTRU is authenticated, at step S 9 . Thereafter, the SGSN provides a WTRU capability update to the WAG-PDG, at step S 10 , and provides an attach-accept message to the RNC, at step S 11 , which is then conveyed, at S 12 , to the WTRU. 
     The update of the WTRU capability sent to WAG-PDG, at step S 10 , causes the SGSN to update the WAG, which may then decide if the service request can be terminated. 
     The purpose of a mobile station WTRU network capability information element is to provide the network with information concerning aspects of the WTRU related to the GPRS. The contents of the information element can affect the manner in which the network handles the operation of the WTRU. WTRU network capability information indicates general WTRU characteristics and, except for fields explicitly indicated, is independent of the frequency band of the sending channel. 
     WTRU network capability is a type 4 information element (IE) having a maximum length of ten octets. 
     The value part of the WTRU network capability IE is coded, as shown in  FIG. 3 . 
       FIG. 4  is a comparison of the existing network capability IE with the network capability information element of the present invention and  FIG. 5  shows a comparison of the radio access capability information element (RAC IE) with the RAC IE of the present invention. 
     The purpose of the mobile station (MS) network capability IE is to provide the network with information concerning aspects of the mobile station (i.e., WTRU) related to GPRS. The contents can affect the manner in which the network handles the operation of the mobile station. The MS network capability information indicates general mobile station characteristics and except for fields explicitly indicated, is independent of the frequency band of the channel it is sent on. The MS network capability is a type 4 information element with a maximum of ten octets length. The value part of a MS network capability information element is coded as shown in  FIG. 3 . 
     Making reference to  FIG. 4 , which shows the network capability IE in amplified fashion, item (1) of both the existing and new IE, namely the system management capabilities by way of dedicated channels, are the same. Item (2) listed in the existing and new IE, the system management capabilities by way of GPRS channels are the same. Item (3) in the existing IE, and item (6) in the new information element, the Universal Multiple—Octet Coded Character Set (UCS), USC2 16 bit coding support, are the same. 
     Item (4) in the existing IE and item (7) in the new IE, i.e. the supplementary service screening indicator, are the same. The support of localized service area (SoLSA) capability, item (5) of the existing IE and item (8) of the new IE, are the same. 
     Item (6) in the existing IE, the revision level indicator, is the same as item (9) in the new IE. Items (4) and (5) in the new IE, namely, the system management capability by way of the WLAN and the short message system (SMS) item which identifies text only, text and animation, the instant message service and the multimedia service as well as others are provided to the WTRU, are not provided in the existing IE. Items (7) through (10) of the existing IE are omitted from the new IE and will not be discussed herein for simplicity. 
       FIG. 4A  shows the network capability IE in greater detail. For example, as shown in  FIG. 4A , the location service (LCS) value added (VA) location request notification bit, (in binary format) is “0” when not supported and is “1” when supported. WLAN capability is supported when its binary bit is “1” and is not supported when in the “0” state. The bit or bits identifying each capability are assigned predetermined locations with the IE. This is also the case for the RA capabilities. Also note that the GPRS encryption algorithm (GEA) capability bit is “0” when not supported and “1” when supported. 
     The purpose of the mobile station radio access (MS RA) capability information element (IE) is to provide the radio part of the network with information concerning radio aspects of the mobile station (i.e., the WTRU). The contents can affect the manner in which the network handles the operation of the mobile station. The MS RA capability is a type 4 information element, with a maximum length of 52 octets. The value part of a MS RA capability information element is coded as shown in  FIGS. 5A and 5B . 
       FIG. 5  compares the existing and new radio access capability IEs. Items (1) through (4) of the existing IE, namely the access technology type, access capabilities, UMTS FDD RA technology capability and UMTS 3.84 Mcps TDD RA technology capability, are identical to the items (1) through (4) in the new IE. 
     Items (5) and (6) in the existing IE are omitted from the new IE and hence will not be discussed herein for purposes of simplicity. Item (5) of the new IE does not appear in the existing IE and provides WLAN radio access capability which identifies the type of remote terminal, (such as PDA, laptop, phone, etc.), memory size, screen size, processing power, technology version (such as 802.11, 802.15, 802.16 and so forth), service profile, (such as SMS text only or text and animation), MMS, IMS, location, MBMS, and the like. 
     FIGS.  5 A 1 - 5 A 2 / 5 B show the MS RA capability IE in greater detail. In FIGS.  5 A 1 - 5 A 2 , the Access Technology type of four binary bits, represents the technology type used for access. Gaussian minimum shift keying (GMSK) is a form of frequency shift keying providing good spectral efficiency. 8PSK is a modulation technique where the carrier exists in one of eight states.  FIG. 5B  shows the fields and binary dates for identifying some of the capabilities. For example, a three bit field is used to identify WLAN 802 RA Technology wherein the technology supported is identified by a particular combination of binary bits. Note that no support of WLAN 80.xx technology is represented by “000,” support for WLAN 802.11b technology represented by “001” and so forth. As another example, the CDMA 2000 RA Technology capability is “0” when not supported and “1” when supported. 
     A dual mode WTRU provides a WLAN capability report over its UMTS (or GPRS) network depending on whether the dual mode WTRU has WLAN/UMTS or WLAN/GPRS capability. 
     As shown in  FIG. 2 , when the WTRU is powered up, it first communicates by way of the UMTS channels and performs a non-access stratum (NAS) “ATTACH” procedure whereupon the UMTS/WLAN capability is exchanged with the network, as shown in  FIG. 2 . 
     Depending on implementation, the user may chose to continue communicating with the UMTS network, manually switch over to WLAN channels or perform an automatic handover to the WLAN network, if available. 
     The present invention thus introduces two new IEs to existing GPRS/UMTS capability messages between WTRU and network and network and WTRU. The radio access capability information element (RAC IE) is modified to inform the network about the dual-mode capabilities of the WTRU/card, i.e., GPRS+WLAN or UMTS/WLAN. The radio access capability (RAC), carries all aspects of the WLAN capabilities including terminal type, (such as PDA, laptop, cell phone), memory size, screen size, processing power, technology version (such as 802.11, 802.15, 802.16 and so forth), service profile (such as SMS text only or text and animation), SMS, MMS, IMS, location, multicast broadcast media service (MBMS) and so forth. The WLAN capability update procedures are achieved without modification of the existing “ATTACH” procedure. The network capability is modified to inform dual mode WTRUs regarding the existence of WLAN interworking capabilities and the different types of services that can be provided over a WLAN network.