KR20070112231A - Wireless communication systems and apparatus and methods and protocols for use therein - Google Patents

Abstract

A wireless communication system (100, 200, 300) comprises a wireless local area network (WLAN) operably coupled to a private mobile radio system (160) and arranged such that a wireless communication unit (112, 116) is capable of private mobile communication with the private mobile radio system (160) over the wireless local area network. Preferably, the private mobile radio system is a TETRA system.

Description

WIRELESS COMMUNICATION SYSTEMS AND APPARATUS AND METHODS AND PROTOCOLS FOR USE THEREIN

The present invention relates to a wireless communication system and apparatus and a method for use therein. In particular, the present invention relates to the use of wireless local area network (WLAN) technology by wireless communication systems. The present invention may be applied to, but is not limited to, facilitating and supporting WLAN features in TETRA (Terrestrial Trunked RAdio) communication systems.

Over the years, the development of wireless communications has been dramatic. Many wireless communications have been standardized so that not only all communication units provide the same level of performance in a particular communication field, but also facilitate the interoperability of communication between different manufacturers. One technique for undergoing this rapid development and standardization is a wireless local area network (WLAN). The purpose of a WLAN is to provide wireless connectivity at bit rates faster than 100 Mbps. WLANs also provide improved security, improved mobility management, inter-operation with cellular networks, and the like. Thus, WLAN technology is expected to play a key role in the wireless data market for years to come.

Moreover, WLANs are currently being enhanced to provide guaranteed quality of service (QoS), which is an IEEE standard 802.11e / D6.0, "Part II: Wireless Media Access Control (MAC) and Physical Layer (PHY) specification." : MAC QoS Enhancements "(November 2003). This is an additional reason why WLAN solutions for voice and video are quickly created in the data market.

A wireless communication system (e.g., cellular telephony or private mobile wireless communication system) includes a system infrastructure in which the wireless communication link includes a plurality of base transceiver stations and a plurality of subscriber units or terminals (often a mobile station). ; Referred to as MS)). An example of a zone / cell-base wireless communication system is the TETRA system, which operates according to the TETRA standards and protocols defined by the European Telecommunications Standards Institute (ETSI). The main focus for TETRA devices is that they are emergency services because TETRA provides dispatch and control services. The system infrastructure of the TETRA system is referred to generically as the Switching and Management Infrastructure (SwMI), which includes substantially all of the communication components away from the MS.

The communication network may provide wireless communication of information between the infrastructure and the MS (or between MSs through the infrastructure), which information is any known form in which such communication is possible. In particular, the information may represent speech, sound, data, picture or video information. Data information is primarily digital information (ie, the type of user information processed on a personal computer) representing handwritten words, numbers, and the like. In addition, signaling messages are delivered. These are messages related to the communication system itself, for example for controlling how user information is conveyed in accordance with selected industrial protocols such as TETRA. Different channels can be used to convey different types of information.

A communication terminal processing protocol is required so that data is transmitted over a communication network through a data communication channel. In general, an address is assigned to a communication unit, which is read by a communication bridge, gateway and / or router to determine how data is transmitted to an addressed destination communication unit. Such data transmission needs to be provided efficiently and efficiently to optimize the use of limited communication resources. Currently, the most popular protocol used to transmit data in communication systems is the Internet Protocol (IP).

IP adds a data header to the information conveyed from the transport layer. The resulting data packet is known as an internet diagram. The header of the diagram contains information such as the destination and source IP address and the version number of the IP protocol. Each data exchange typically includes transmitting one or more data packets on an uplink channel and transmitting one or more data packets on a downlink channel. A Packet Data CHannel (PDCH) in a TETRA network can serve several MSs at the same time. In this regard, the resources of the PDCH are shared between MSs on a channel on a statistical multicast basis. This allows air interface resources to be used in an optimal manner.

The TETRA known signaling procedure used to access the PDCH first requires the MS to request access to the PDCH via a main control channel (MCCH), which primarily transmits a control signaling message. Following an access grant by SwMI and sending the appropriate signaling message to the MS, the MS can then be moved to the PDCH where data packets are exchanged by the receipt of the signaling message.

In TETRA packet data communication, the physical data channel carries both system control signaling and data payload (user delivery information). The two types of traffic can be given different attributes along with control signaling, which is primarily assigned higher priority. TETRA packet data communication is now at up to 28.8kbits / sec, which is considerably slower than some other wireless communication technologies such as WLAN.

The inventors thus recognize that there is a need for improved mechanisms and associated apparatus, methods and communication protocols for improving the data rate provided to TETRA-capable communication units (where the disadvantages / limitations described above can be mitigated).

According to a first aspect of the invention, a wireless communication system is provided. The wireless communication system includes a wireless local area network (WLAN) operatively connected to a private mobile wireless system and configured to enable private mobile communication with the private mobile wireless system over a wireless local area network.

In accordance with the second, third and fourth aspects of the present invention, a wireless local area network (WLAN) configured to facilitate communication across a private mobile wireless system such as a wireless local area network (WLAN) and a TETRA system in the aforementioned wireless communication system. An access gateway (WAG), an interworking function (IWF), and a wireless terminal are each provided.

According to a fifth aspect of the present invention, there is provided a method of communicating between a wireless local area network (WLAN) and a private mobile wireless system by a dual-mode terminal capable of operating across a WLAN and a private mobile wireless system. do. The method includes receiving a message from a dual-mode terminal requesting association with a WLAN using the identified particular service set identifier (SSID); Creating a tunnel to route private mobile wireless communications to or from the terminal via a WLAN; And assigning an address to route communication to or from the terminal. The method includes extracting an assigned address; And processing the forwarded packet comprising routing the packet to or from the terminal in response to the extracted assigned address.

According to a sixth aspect of the present invention, a protocol is provided for facilitating the aforementioned communication between a wireless local area network (WLAN) and a private mobile wireless system.

Further features of the invention are defined in the dependent claims.

Embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings.

1 is a schematic diagram of a WLAN inter-operating with TETRA switching and management infrastructure (SwMI) constructed in accordance with a preferred embodiment of the present invention.

FIG. 2 is a further schematic diagram of a WLAN inter-operating with TETRA switching and management infrastructure (SwMI) including various logical interfaces. FIG.

3 illustrates the mechanism of traffic flow between ToW terminals tunneled through an IP network.

4 illustrates a protocol architecture of a ToW terminal according to a preferred embodiment of the present invention.

5 illustrates a preferred packet structure for use within TETRA over WLAN architecture,

6 illustrates a preferred packet structure of a control-plane packet transmitted by the IWF, including a D-SETUP message.

7 and 8 illustrate an exemplary signaling flow of TETRA across a WLAN system, in accordance with a preferred embodiment of the present invention.

In summary, a preferred embodiment of the present invention proposes to integrate WLAN technology with a private mobile radio system, which is a TETRA system defined by ETSI and the like. The proposed system architecture of both WLANs interoperating with TETRA switching and management infrastructure (SwMI) is shown in the schematic diagram of FIG.

A preferred embodiment of the present invention proposes a dual-mode wireless communication unit. Dual-mode operation uses a first private (or air) mobile radio technology such as TETRA and a second WLAN technology. A wireless communication terminal, hereinafter referred to as a TETRA over WLAN (TOW) terminal 116, interfaces with a TETRA switching and management infrastructure (SwMI) 160 via a WLAN air interface 115. This is in contrast to a conventional TETRA terminal 132 that interfaces with the TETRA SwMI 160 via a conventional TETRA Enhanced Base Transceiver (EBTS) 1354 over a conventional TETRA air interface and communication link 135. Thus, dual Mode TETRA and WLAN supported terminals are described.

In the context of the present invention, ToW terminal 116 is any WLAN terminal capable of interfacing with TETRA SwMI 160 and configured to use TETRA services by the protocols and functions described herein. ToW terminal 116 is preferably associated with a WLAN by using a specific service set identifier (SSID).

Preferred examples of SSIDs are described in IEEE Standard 802.11, 1999, entitled "Wireless LAN Media Access Control (MAC) and Physical Layer (PHY) Specification". By this particular SSID, the WLAN can distinguish between ToW terminals and non-ToW terminals to apply different routing and / or access control policies.

The WLAN preferably implements a specific routing enforcement policy for the ToW terminal 116. That is, the WLAN tunnel uplinks packets from all ToW terminals 116 to the Interoperation Function (IWF) 150 via the Ft tunnel. Thus, the Ft interface operates between the WAG 142 and the IWF 150 and implements a tunneling scheme for tunneling IP packets through the IP network 140 between the WAG 142 and the IWF 150. Is preferably used.

While the preferred embodiment uses a 'Ft tunnel' as known in the art, it is understood that any possible tunneling scheme could be used, for example IP encapsulation, GRE, and the like. If IWF 150 is interconnected with WAG 142 via a leased line, tunneling may be eliminated. Thus, packets originating from any ToW terminal 116 are routed to IWF 150 via an Ft tunnel.

3 illustrates a preferred mechanism of how traffic from ToW terminals is tunneled to IWF 150 and how traffic from all other terminals is routed to the Internet or intranet.

All ToW terminals preferably implement the protocol architecture and procedures described below to support TETRA services over the WLAN. Physically, it is understood that the ToW 116 may be any kind of wireless communication device (ie, personal computer (PC), laptop, PDA, dual-mode WLAN / TETRA terminal, etc.) having a WLAN interface. .

From the SwMI point of view, the ToW terminal 116 may be considered any TETRA terminal. That is, it is preferable that the ToW terminal 116 is assigned a TETRA ISSI (Individual Short Subscriber Identity). Accordingly, the ToW terminal 116 can be started to participate in a group call and receive / receive a Short Data Service (SDS) message. It is possible to transmit and generally use any authenticated service provided by TETRA SwMI 160. Thus, the ToW terminal 116 may communicate with other ToW terminals by a conventional TETRA terminal by a dispatcher, a PSTN user, and other TETRA entities according to a subscriber profile in the SwMI 160.

ToW terminal 116 preferably utilizes all known TETRA services, including group calls, SDS messaging, packet services, and the like. In terms of SwMI, ToW terminal 116 is no different from any other conventional TETRA terminal 132.

Advantageously, the characteristics of the WLAN air interface 115 include high speed data services, simultaneous voice and data, improved voice quality, reduced call setup and voice transmission delays, simultaneous reception of multiple group calls, voice and / or data Enables new features and extended capabilities such as monitoring primary control channel (MCCH) traffic. Thus, TETRA terminals (eg, ToW terminals 116) benefit from the known advantages of WLAN technology.

ToW terminal 116 operates at a WLAN site, which may be considered a geographic area where WLAN coverage is provided and controlled by a single WLAN access gateway 142. WLAN sites typically include one or more APs. ToW terminal 116 has a wireless interface to WLAN access point 114. The WLAN access point 114 interfaces with the WLAN terminal via any kind of WLAN interface, for example using IEEE 802.11 WLAN technology, which is a " wireless LAN media access control (MAC) and physical layer (PHY) specification. Is published by the IEEE in the IEEE Standard 802.11, 1999 edition. The WLAN access point has an interface 115 to an Internet Protocol (IP) network 140 through one or more WLAN access gateways 142. IP network 140 is operably connected to TETRA SwMI 160 via key components of the proposed system (ie, interworking function (IWF)).

IWF 150 is configured to interface 155 with SwMI in a manner similar to TETRA conventional base station 134. IWF 150 also interfaces with one or more WLAN access gateways (WAGs) 142. In effect, the WAG 142 controls a single WLAN site as a router, or a combination of routers and Ethernet switches. The WAG typically interfaces with one or more APs 114 over Ethernet 100BaseT media. Preferably, one WAG is assigned to each WLAN site. When there is a ToW terminal in the WLAN site, the WAG 142 preferably creates an Ft tunnel with the IWF 150. It is understood that any known tunnel establishment protocol may be used, for example PPTP, L2TP, IPsec. WAG 142 then applies the appropriate routing enforcement policy (the preferred example shown in FIG. 3). In addition, when there are no more ToW terminals in the WLAN site, the WAG 142 preferably releases the Ft tunnel to free up capacity. It is also understood that there may be fixed Ft tunnels that are created / unresolved dynamically.

Clearly, both WAGs and APs are off-the-shelf devices, and their configuration is typical for known WAGs and APs, except for signal processing functions that support TETRA SSIDs and are configured to route these TETRA communications as determined by the SSID. will be.

IWF 150 transmits a control packet data unit (PDU) and voice packet to ToW terminal 116 using known IP multicasting techniques.

Thus, in this manner, the mobile or fixed ToW terminal 116 is provided to the typical services provided by the TETRA SwMI 160 by corresponding software drivers and applications and the WLAN network interface 115 as will be apparent to those skilled in the art. Can be accessed. ToW terminal 116 reuses a number of TETRA air interface protocols, which are described in ETSI document-EN 300 392-2 v2.3.10, "TETRA; Voice + Data (V + D); Part 2: Air Interface (AI)". , ETSI (June 2003). Clearly, the ToW terminal 116 reuses multiple TETRA air interface protocols on top of the WLAN air interface. TETRA SwMI 160 is preferably built on IP multicast and Voice-over-IP (VoIP) technology, so interfacing with IWF 150 is relatively straightforward and will also be apparent to those skilled in the art.

Interaction function (IWF) 150 is a key functional component that interfaces with TETRA SwMI 160 via any suitable interface, such as a proprietary interface, and also interfaces with one or more WAGs 142 via an Ft interface. Clearly, one function of the IWF 150 is to hide the characteristics of the WLAN from the SwMI 160 so that they are easily integrated with the SwMI 160.

Referring now to FIG. 2, a further schematic diagram of a WLAN interoperating with TETRA switching and management infrastructure (SwMI) is shown, which includes the logical interface of the system of FIG. 1. As can be seen, many system / infrastructure components are similar to those described with reference to FIG. 1. Thus, they will not be described further herein.

Again, the WLAN preferably implements a specific routing enforcement policy for the ToW terminal by tunneling uplink packets from all ToW terminals to the Interworking Function (IWF) 150 via the Ft tunnel. Thus, the Ft interface preferably operates between the WAGs 142, 225 and the IWF 150. The private interface 155 is shown between TETRA SwMI 160 and IWF 150. It is appreciated that IWF 150 may also use logical links to ToW terminals 112 and 116 via Ut interface 210. In this regard, the Ut interface 210 supports protocols and procedures for managing communication between the ToWs 112 and 116 and the IWF 150. As described below, the new protocol operates on this logical interface 210.

In addition, the logical interface Wt is applied to the communication link between the WAGs 142 and 225 and the ToW terminal. The Wt interface supports protocols and procedures for managing communication between (fixed or mobile) ToW terminals and APs. This interface preferably conforms to the IEEE 802.11 basic specification.

Referring now to FIG. 3, in accordance with a preferred embodiment of the present invention, a preferred mechanism for traffic flow between ToW terminals tunneled through an IP network is shown. As shown in FIG. 3, the ToW terminal 116 wants to communicate with the TETRA SwMI 160, sends an association request with SSID = TETRA to the access point 114, and relays the request to the associated WAG 142. do.

As described above, the SSID of the ToW terminal is preferably a well-known predefined one, for example, "TETRA", "Dimetra", "TETRAoverWLAN" and the like. Similarly, the SSID used by non-ToW may be such as "Public", "Motorola ™", "Wireless-HotSpot", "ANY", "Operator-A", and the like. In this regard, the difference between ToW SSIDs and non-ToW SSIDs is that the WLAN is only configured to handle them differently. In contrast, they are preferably all alphanumeric strings that conform to the 802.11 specification. The WLAN service provider is preferably free to select his preferred ToW SSID and inform his customer of the SSID. The customer will then configure this ToW as a terminal.

Typically, the AP will map traffic from / to different SSIDs to differentiate the WLAN on the Ethernet interface.

The WAG 142 tunnels all such traffic from the ToW terminal (ie related to the ToW SSID) from the WLAN to the IWF 150 and transmits them over the IP network 140 via the Ft tunnel. The IWF 150 then forwards them (as indicated) to the TETRA SwMI 160, preferably via the proprietary interface 155.

Referring now to FIG. 4, an overview of a communication layer associated with TETRA communication via a WLAN system is shown. The preferred communication architecture is similar to the ETSI EN 300 392-2 TETRA specification. That is, the control panel 410 information includes the SNDCP 415, mobility management (MM) 420, and call management control entity (CMCE) 425. Mobile link entity (MLE) 430 and logical link control (LLC) layer 435 are also supported.

In the user edition 440, using a real-time protocol (RTP) or compressed RTP protocol 450, a TETRA ACELP (Adaptive Code Excited Linear Predicted) encoded speech block 445 according to ETS 300 395 is placed between the ToW and IWF. send. Typically, one voice block is generated every 30 seconds. At the control panel, all TETRA air interface protocols are reused except TETRA MAC and physical layer protocols, which are not applicable to WLAN radio access. The LLC layer supports both basic link services and advanced link services, which are described in ETTSI, EN 300 392-2 v2.3.10, "TETRA; Voice + Data (V + D); Part 2: Air Interface (AI)", ETSI (June 2003). The LLC layer operates within ToW and IWF (partially within SwMI).

Clearly, a new layer of communication, namely the adaptation layer 460, is specific to the ToW system. The adaptation layer 460 provides the adaptation functionality required to require the TETRA air interface protocol to operate over the WLAN. The adaptation layer 460 is implemented in ToW and IWF and provides a service that includes a subset of the services provided by the TETRA MAC layer. In particular, it supports addressing using TETRA-compliant encryption and TETRA SSI.

The adaptation layer interfaces with the UDP layer via a control-panel-service access point (CP-SAP) 465 and one or more user-panel-service access point (UP-SAP) 470. CP-SAP 465 always forwards control-panel traffic that is present and not associated with an ongoing call, ie, typically controls traffic carried on TETRA MCCH or SCCH.

Well-known (predefined) which are respectively referred to as MCCH-multicast and MCCH -port multicast IP address and a port number used to transmit this kind of traffic.

In contrast, user plane traffic is carried on the UP-DSP 470. At the start of a new call, a new UP-SAP 470 instance is created to support that particular call. The UP-SAP 470 instance uses a dynamically assigned multicast IP address and port number. As described below, this multicast IP address and port number are assigned by the IWF and passed to the ToW in a packet signaling the start of a new call. The UP-SAP 470 is dynamically generated to support user data, traffic and call association control traffic. Obviously, the UP-SAP 470 also supports control-panel traffic 410 associated with an ongoing call (eg, D-TX-CEASED PDU). The adaptation layer is used to distinguish between user- edition traffic and call-associated control traffic on the same UP-SAP.

The adaptation layer 460 in the ToW analyzes every received packet and recognizes whether it should be further processed or dropped (based on the indicated SSI). If further processing is required, the adaptation layer indicates whether decryption should be applied (ie, if the received message is encrypted), and if the received packet is received via UP-SAP, then it receives the received packet. Forward to LLC entity or RTP entity.

4 shows a further aspect of the protocol architecture of a ToW terminal. The WLAN physical layer 490 and the WLAN MAC layer 485 are used to establish a broadband wireless connection with the AP. These layers are preferably in accordance with the IEEE 802.11 specification described in the document published in IEEE Standard 802.11, 1999, entitled "Wireless LAN Media Access Control (MAC) and Physical Layer (PHY) Specification". However, it is understood that any WLAN can be used.

These layers are also described in IEEE Standard 802.11e / D6.0, "Part II: Wireless Media Access Control (MAC) and Physical Layer (PHY) Specification: Media Access Control (MAC) and Quality of Service (QoS) Enhancements" (11 November 2003). Follow a specific quality of service (QoS) improvement within a month).

These layers are also referred to as IEEE, "Port-Based Network Access Control", IEEE Standard 802.1x, 2001 Edition, and IEEE Standard 802.11i / D7.0, "Part II: Wireless Media Access Control (MAC) and Physical Layer ( PHY) specification: media access control (MAC) and security enhancements "(October 2003).

Connection to the IWF is provided by the IP layer by service routing and addressing, as shown in J. Postel's paper entitled "Internet Protocol" published in RFC 791 in September 1981.

The UDP layer provides error detection and multiplexing services, as shown in a paper by J. Postel entitled "User Datagram Protocol" published in RFC 0768 in 1980.

The IP layer is implemented in ToW terminals, IWF and intermediate IP networks (see FIG. 1). The IP layer ensures that all IP datagrams from / to ToW are routed to / from IWF. If necessary, it can also enable different quality of service (QoS) routing to different kinds of IP datagrams, depending on the type of service (ToS) in their respective IP header. Such QoS service may be required to provide a preferred transport service for IP datagrams carrying voice packets.

Referring now to FIG. 5, there is shown a preferred packet structure 500 for use in a ToW architecture. In FIG. 5, the general format of the control-panel 510 and user-panel 550 packets exchanged over the Ut interface (ie, transmitted between the IWF and ToW terminals) is shown.

The control-panel packet 510 carries a conventional TETRA LLC PDU 530 encapsulated in IP / UDP. The structure of the adaptation layer header is a key component of the inventive concept described herein. The structure of all other protocol fields (eg, IP 515, UDP 520, RTP, LLC, CMCE, MLE, MM, SNDCP 535) is designed to comply with known protocol specifications.

That is, the LLC, CMCE, MLE, MM, and SNDCP protocol fields are described in document ETSI, EN 300 392-2 v2.3.10, "TETRA; Voice + Data (V + D); Part 2: Air Interface (AI)", ETSI ( June 2003). The IP protocol field is further described in J. Postel's article, "Internet Protocol", RFC 791 (September 1981). The UDP protocol field is further described in J. Postel's article, "User Diagram Protocol", RFC 0768 (1980).

It is understood that other kinds of TETRA PDUs may also be encapsulated in control-panel packets to broadcast security related information such as, for example, Common Cipher Key (CCK) identifiers or Static Cipher Key (SCK) version numbers. .

Adaptation layer headers 525 and 565 are populated with the critical information typically contained in the TETRA MAC header. In particular, the adaptation layer headers 525, 565 preferably include an encryption mode field and a TETRA SSI field indicating whether the included LLC or RTP PDU is encrypted. In the downlink direction, the TETRA SSI identifies the TETRA address of the packet receiver (s), and in the uplink direction, the TETRA address of the packet originator.

In addition, the adaptation layers 525 and 565 preferably include additional information in the packet that signals the occurrence of a new call (of any kind). In this case, the adaptation layers 525 and 565 also preferably include the multicast address and port number used to transmit the voice packet of the upcoming call. Finally, the adaptation layer headers 525 and 565 preferably include an information field indicating whether there is an LLC PDU or RTP PDU encapsulated in the packet.

Referring now to FIG. 6, an example of how the various headers are populated in a packet 600 carrying a known TETRA D-SETUP message is shown.

The packet 610 is transmitted by the IWF, for example. Packet 610 indicates that a terminal with SSID = 46 makes a group call to GSSI = 8388888. IP address of the IWF 615 is xyzw, and the multicast address and port corresponding to the well-known MCCH address and MCCH port 620, are each MCCH - is designated by mcast -port and MCCH. This packet is sent by the IWF to all WAGs that have already established Ft tunnels. Thus, the packet will ultimately be broadcast to all WLAN sites controlled by this IWF. Thus, all ToW terminals in these sites will receive and decode the packets. Thus, the ToW terminal belonging to GSSI = 8388888 will be configured to receive this user-version information for this group call by creating a new UP-SAP instance. The new UP-SAP 620 of the adaptation layer header is bound to the multicast address g1.g2.g3.g4 and port Gp.

In addition, the packet 650 is transmitted by ToW, for example. Packet 650 indicates that the ToW terminal has SSI = 46 to belong to GSSI = 8388888 group. ToW's IP address 655 is designated as a.b.c.d. In this packet 650, it should be noted that the adaptation layer 665 does not include a multicast IP address and port pair, since the packet does not generate a new call.

Referring now to FIGS. 7 and 8, an exemplary signaling flow of a ToW system in accordance with a preferred embodiment of the present invention is shown. In particular, FIG. 7 illustrates a signaling flow 700 that includes WLAN association and location update.

Signaling flow 700 illustrates communication between ToW terminal 710, AP and WAG of WAL 715, and IWF 720. In step 725, a message sequence occurs when the WALN terminal requests an association with the WLAN using SSID = "TETRA". This occurs when the WLAN terminal is powered up, ie when it chooses to change the radio access technology to leave the TETRA site and join to the WLAN site. In step 730, the WLAN preferably acknowledges the request.

At point 1 735, if there is no existing Ft tunnel with a predefined address of IWF 720, WAG 715 creates such a tunnel. The WAG 715 also generates a forwarding function to forward the next packet from the ToW 710 to the IWF 720 via the Ft tunnel. Next, as shown in steps 740 and 745, ToW 710 initiates a DCHP procedure and obtains an IP address. This IP address, typically assigned by IWF 720 at step 745, uses an internal DCHP server or possibly an external DHCP server.

At point 2 750, ToW 710 enables CP-SAP and begins receiving packets with a destination IP equal to MCCP -multicast and a UPD port equal to MCCP -port . The values of the MCCH-multicast and MCCF-ports are assumed to be preconfigured in the ToW 710. However, it is appreciated that other means for transmitting these parameters to ToW 710 may also be developed if necessary.

After point 2 750, the adaptation layer in ToW 710 begins to receive and process packets 755, 760, and 765, which typically include TETRA traffic transmitted on the MCCH channel.

At point 3 770, ToW 710 sends U-LOCATION-UPDATE-DEMAND PUD 775 to IWF 720 to request SwMI to update its location. This PDU 775 is transmitted on the CP-SAP, whereby the destination IP address is the same as MCCH-multicast and the destination UDP port is the same as the MCCH-port. The D-LOCATION-UPDATE ACCEPT PDU 775 is transmitted from the IWF 720 to the ToW terminal 710.

Those skilled in the art will appreciate that FIG. 7 shows only simple examples of association request and location update messages, and is not intended to show all possible communications.

Referring now to FIG. 8, a signaling flow 800 is shown that includes a message sequence for initiating and joining a group call. The signaling flow 800 represents communication between the ToW terminal 805, the AP and WAG of the WLAN 810, and the IWF 815.

An indication of a new group call 820 for ToW terminals belonging to group '8388888' is received at IWF 815. The destination multicast address and destination UDP port (associated with the new group call) of packet 825 are the well-known MCCH-mcast and MCCH-port, respectively. The adaptation layer header in this packet indicates that the new group call will use the IP multicast address g1.g2.g3.g4 and UDP port Gp. This is shown in the MCCH D-SETUP message 825 from the IWF 815 to the ToW terminal 805. All ToW terminals in the WLAN area of the IWF receive this packet whether or not they are involved in the call. ToW terminals belonging to group '8388888' and wishing to participate in this group call will create a new UP-SAP instance and bind it to the specified multicast address and UDP port (ie g1.g2.g3.g4 / Gp). . ToW terminal 805 with SSI = '90 'receives this group call.

After receiving the MCCH D-SETUP message 825, a series of IP multicast diagrams are sent from the IWF 815 to the ToW 805. Each diagram 830, 835 carries a voice packet from the generator. Diagrams 830 and 835, and possibly the following diagrams, indicate in the adaptation layer header that they carry encrypted RTP PDUs for groups with GSSI = 8388888.

Diagram message 840 is a call-associated control packet carrying a D-TX end PDU. The adaptation layer in ToW 805 understands that it carries the LLC PDU (unlike RTP PDUs) and thus forwards it to the LLC layer indicated in the information field. After the diagram message 840, the ToW 805 under consideration decides to take control of the group call and accordingly sends an uplink call-associated control packet 845. The uplink call-associated control packet 845 carries a U-TX request PDU requesting to send a grant from SwMI.

In response, SwMI grants permission to transmit to ToW 805 with a D-TX grant message 850. Accordingly, starting from message 855, ToW 805 sends a series of user-version packets containing an encrypted RTP PDU.

In an improved embodiment of the present invention, security and authentication procedures can be easily integrated into the ToW system. The authentication process can be easily supported by exchanging the appropriate layer-3 messages, such as D-AUTHENTICATION DEMAND and U- / D-ANTHENTICATION RESPONSE, between the ToW and the IWF, which are ETSI, EN 300 392-7 v2. .1.1, "TETRA; Voice + Data (V + D); Part 7: Security" (February 2001).

During this procedure, the adaptation layer in the ToW responds to activate the appropriate security algorithm and generate a Derived Ciphering Key (DCK). This key is used substantially by the adaptation layer to encrypt and decrypt all LLCs and PDUs over the Ut instance. Support for SCK and CCK is also possible. The CCK is generated by SwMI, which not only protects SSI identification, but also protects group addressed signaling and traffic.

In addition, yet further improved embodiments of the present invention will support individual and telephone interconnect calls in a manner similar to that for the signaling flow for group calls described above. Those skilled in the art will appreciate that other procedures and corresponding signaling flows (eg, for SDS and packet data transmission / reception) can be readily adapted and integrated using the principles and protocols described above.

Accordingly, the concept of the present invention proposes a mechanism for integrating WLAN technology into a TETRA network, thus providing the advantages of such WLAN technology to TETRA products and services. The proposed mechanism is based on IP multicast and VoIP technology.

The foregoing architectures, devices, functional components, protocols and signaling flows that implement the inventive concepts described above tend to provide at least one or more of the following advantages:

(Iv) Integration of WLAN and TETRA networks offers a wide range of new capabilities and benefits that will create differences and competitive advantages.

(Ii) Office clerks and other business users may use dual-mode TETRA / WLAN terminals in their fields as well as within an office environment and / or over a private WLAN.

(Iii) At strategic locations such as airports, hotels, shopping areas, etc., TETRA services may be provided via WLAN. This enables better indoor coverage, increased performance, new services and more in a cost effective manner.

(Iii) With WLAN, enhanced services are provided to end users. E.g:

(a) an enhanced speech encoding scheme (ie no need for the constraints of 7.2 kbps performance provided by TETRA TCH / S) to provide much improved speech quality;

(b) broadband data services may be supported;

(c) voice and data services may be provided simultaneously;

(Iii) Control traffic typically sent on the TETRA MCCH may now be received while the voice and / or data session is active. In conventional TETRA, terminals in a voice session are also unable to receive control traffic on the main control channel (MCCH) because voice and MCCH traffic are sent on different channels. However, according to a preferred embodiment of the invention with TETRA communication over WLAN, this is now possible.

(Iii) Those skilled in the art will appreciate that by IP multicast, multiple group calls can be monitored simultaneously by one user, and the like.

(I) WLAN Features Extends air interface performance and can therefore support multiple simultaneous TETRA voice / data calls in an efficient and cost effective manner.

(Iii) Those skilled in the art will also recognize that call setup delay and voice transmission delay can be significantly reduced. Thus, as WLANs support higher bit rates, control messages and voice datagrams are transmitted faster.

(Iii) Inexpensive subscriber devices may be supported—cellular with any PC, PDA or WLAN adapter may be used.

(Iii) Dual-mode WLAN / cellular mobile terminals are rapidly integrated into the market, and these terminals can also support TETRA services across the WLAN.

(Iv) the possibility of supporting seamless roaming between WLAN access and conventional TETRA access: that is, mobile enters into the WLAN area is treated in a similar manner as new ones enter into the TETRA location area. In the new TETRA location area, they update the SwMI to their new location using a typical TETRA mobility management procedure.

(Iii) Supplemental TETRA features (eg, Late Entry, etc.) can easily support-some of them have less SwMI processing or intervention (eg, priority monitoring).

(Iii) A TETRA terminal may simultaneously participate in group call (s), data session (s), and also typically receives information transmitted on the MCCH. This creates new performance that is not possible with conventional TETRA radio systems.

(Iii) WLAN is mainly used as a new radio access scheme for the transmission of TETRA control and user data PDUs.

(Iii) The preferred architecture has minimal impact on TETRA SwMI. IWF can be considered as a particular kind of TETRA base station controller that can easily interface with the SwMI core.

(Iii) Local Site Trunking in the WLAN area can be easily supported by appropriate IWF engineering.

(Iii) The two terminals can be managed in a similar manner as any other TETRA terminal, i.e. no new subscriber profile is required.

(Iii) Full compatibility between ToW terminals and conventional TETRA terminals is maintained.

While specific implementations of the invention have been described, those skilled in the art clearly recognize that variations and modifications of those implementations falling within the scope of the appended claims may also be readily applied.

Thus, communication across wireless mobile systems, wireless local area network (WLAN) access gateways (WAGs), interoperability functions (IWFs), and private mobile wireless systems such as wireless local area networks (WLANs) and TETRA systems within the wireless communication systems described above. A wireless terminal adapted to facilitate this is described.

In addition, a dual-mode terminal capable of operating across a WLAN and a private mobile wireless system between a wireless local area network (WLAN) and a private mobile wireless system, and a method for communicating with the protocol therefor, has been developed by such prior art procedures. Provided by the present invention which tends to alleviate the disadvantages.

Claims (10)

In the wireless communication system (100, 200, 300), A wireless local area network (WLAN) is operably connected to a TERE (Terrestrial Trunked RAdio) wireless system 160 and wireless communication units 112 and 116 communicate with TETRA wireless system 160 via the wireless local area network. A wireless communication system (100, 200, 300) arranged to be. The method of claim 1, The wireless communication system (100, 200, 300) includes a terminal 116 capable of TETRA wireless communication over a WLAN, the terminal 116 is a terminal capable of TETRA wireless communication over the WLAN (WALN) 116) and the wireless communication system 100, 200, 300 associated with the WLAN using a specific service set identifier (SSID) to distinguish between terminals that are not capable of TETRA wireless communication over the WALN. ). The method according to claim 1 or 2, The WLAN includes or is operably connected to a WLAN access gateway (WAG) 142 and an interworking function (IWF) 150 arranged to interface communication between the WLAN and the TETRA wireless system 160. Wireless communication systems 100, 200, 300. The method of claim 3, The WALN provides a specific routing enforcement policy for the terminals 116 to tunnel uplink packets from the terminal 116 capable of TETRA wireless communication over the WLAN to the interworking function (IWF) 150. wireless communication system (100, 200, 300) for implementing a policy). The method according to any one of claims 1 to 4, Communication between the WLAN and the TETRA wireless system 160 may include an adaptation layer that interfaces with a control-panel-service access point (CP-SAP) 465 and one or more plate-service access points (UP-SAP) 470. A wireless communication system 100, 200, 300, supported by 460. The method according to any one of claims 1 to 5, The adaptation layer is configured to distinguish between user- plate traffic and call-associated control traffic on the same access point. The method according to claim 5 or 6, The header of the adaptation layer message includes a TETRA SSID and / or cryptographic mode field, in the downlink direction, the TETRA SSID identifies the TETRA address of the data packet receiver and / or in the uplink direction, the TETRA SSID is a data packet. A wireless communication system (100, 200, 300) identifying a generator's TETRA address. The method according to any one of claims 1 to 8, The adaptation layer message is configured to set up a group call. The method according to any one of claims 5 to 8, The adaptation layer message includes an information field for identifying whether an Encapsulated Logical Link Control (LLC) Packet Data Unit (PDU) or RTP PDU is present in the packet. 1. A method of communicating between the WALN and the TETRA wireless system 160 in a dual-mode terminal 116 capable of operating across a WLAN and TETRA wireless system 160. Receiving (725) a message from the dual-mode terminal requesting association with the WLAN using, for example, service set identification (SSID); Creating (735) a tunnel to route private mobile wireless communications to or from the terminal through the WLAN; Assigning an address (740, 745) to route communications to or from the terminal; Processing (755, 760, 765) the forwarded packets comprising extracting the assigned address; And Routing packets to or from the terminal in response to the extracted assigned address.

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