FI105310B - A method for establishing a call in a wireless access network - Google Patents

Description

, 105310

A METHOD FOR MAKING A CALL IN A WIRELESS LAN

The invention relates to a method as defined in the preamble of claim 1.

5 In WLAN, Wireless

Local Loop 1. An RLL (Radio in the Local Loop) terminal is connected by radio connection to an Access Node (AN). The subscriber network element may consist of multiplexers, cross-connect devices and 10 different transmission systems. The WLL system may be based, for example, on technology used in a mobile communication system, such as GSM / DCS1800 (GSM, Global System for Mobile Communications, DCS, Digital Cellular System). GSM is a 15 pan-European digital mobile communications system standardized by ETSI. The DCS-1800 is a GSM specification based ETSI mobile communication system aiming at more efficient use of microcells and operating in the 1800 MHz band. Between the terminal and the 20 access network element is a base station, by means of which the call signals from the terminal to the base station on the radio channel are forwarded via the access network element to the public telephone network and vice versa. Space and a network element can be combined with voice # | ; 25 link center using, for example, V5.2 protocol according to ETS 300 347-1 or V5.1 protocol ETS 300 «* · .. 324-1. Subscriber Network Element. ti acts as a converter between GSM signaling and V5 signaling.

30 During a wireless LAN, various calls are made in connection with network security management. The checks are to prevent unauthorized access to the network by a user who is not »» · allowed, and to prevent, for example, ·: * 35 use of a stolen mobile station.

· The GSM specification check procedures performed during the call set-up process slow down call set-up to trigger V5 signaling timeouts and to release the call, though most likely to succeed. In a wireless local area network, the rapid establishment of an outgoing 5 call is particularly important.

The call set-up retardation procedure is e.g. a subscriber identity change (TMSI reallocation), which involves changing the temporary identity assigned to the subscriber by the visitor location register, which allows the subscriber to be identified confidentially, for example during a call. Another call slowdown check procedure is subscriber access authentication 1. authentication, which checks mobile subscriber information and prevents unauthorized access to the network. The third procedure for slowing down call setup is the subscriber's device identifier (IMEI check). When checking the device verification code, it is compared to the device verification code register of mobile devices that have been reported stolen and / or defective. IMEI is an international mobile device identifier that uniquely identifies a mobile device.

. In particular, V5 interface PSTN protocol time controls (standard ETS 300 324-111) cause problems with call setup in a wireless local area network system. For example, an end-to-end call has a V5 PSTN protocol timeout, with # · between the start message and the acknowledgment message (phone rings) max. 4 seconds (ETS 300 324-1 13.6).

The object of the invention is to eliminate the above disadvantages.

In particular, it is an object of the invention to provide · '·. discloses a method for accelerating call set-up ·: * so that timeouts 35 are not triggered unnecessarily and redundant calls are made **, and the signaling required for call set-up itself is more time-consuming.

• · · · 3 · 105310

The process according to the invention is characterized in what is set forth in claim 1.

According to the invention, in order to speed up the call set-up, the check functions are performed in the speech mode of the call 5 instead of being performed in the call set-up phase. An advantage of the invention is that more time is needed for the signaling required to establish the call and avoid the possible time-out and unnecessary release of the call.

In one embodiment of the method, the subscriber terminal equipment is connected to a subscriber network element by radio communication according to the GSM specification and performs verification functions including TMSI reallocation, subscriber authentication and / or subscriber identifier verification (IMEI check).

In one embodiment of the method, the subscriber identifier exchange is a 20 TMSI reallocation according to GSM 04.08 4.3.1.

In one embodiment of the method, the authentication of the subscriber is authentication according to GSM 04.08 4.3.2 '.

'·. In one embodiment of the method, the verification of the subscriber's device identifier is according to GSM 04.08.

I «I <·; / 4.3.3 IMEI Verification.

* In one embodiment of the method, V5 interface • 1. is a V5.2 interface according to ETS 300 347-1.

• 1 · V-

In one embodiment of the method, the V5 interface 30 is a V5.1 interface according to ETS 300 324-1.

The figure shows a signaling diagram of a call originating from a TU of a wireless access network, which corresponds essentially to a mobile originated call MOC (Mobile Originated 35 Call) according to GSM specifications. The system components in the diagram are the base station BTS, the access node AN (AN,: ··· Access Node) and the local exchange LE.

* 1 λ 1 «« · • «4 105310

The access node AN has three program blocks called registers. These are the device register, the authentication register and the master register hierarchically above them. The device register contains the device numbers 5 (IMEI). The device number may be whitelisted, grayed out or blacklisted and the device register returns the device in question when the device is checked. IMEI list color. The identification register makes the triplets necessary for identification and contains the information necessary for identification. Task 10 of the main register includes e.g. decision on amendments.

In GSM / DCS world registers, the following terms are used: AUC; AC

(authentication center), equipment identity register (EIR) and visitor location 15 register (VLR). In the case of a wireless access network, a master register program block is called a wireless fixed register (WFR).

The figure shows the call setup of a wireless local area network in a so-called. The non-transparent mode is essentially similar to call setup in a conventional GSM system. In the wireless access network system, the access node AN also has the functions «· · V which are contained in the standard GSM system mobile switchboard / visitor location register, MSC / VLR, and i: '· 25 home location / authentication center / device identity register. I t «| V riin (HLR / AC / EIR). In a wireless access network, subscribe • *: ·. and the terminals are in radio communication with the access • •] ·. went to AN. Signaling between the subscriber terminal and the subscriber network element AN * * · 'is message based signaling according to GSM Specifications 30 (GSM / DCS). The subscriber network element AN, in turn, connects to a fixed network local exchange LE via a V5.2 interface according to ETS 300 347-1 • • * ·.

: T When the subscriber raises the handset, the terminal produces • j · '35 local dial tones. The subscriber has a predetermined period of time to dial the first number. Dial tone • · • Ml «•« · ··· · 105310 5 stops as soon as the first number is dialed. The following item numbering corresponds to the picture numbering.

1. The call will be set up after a predetermined period of time after the last digit has been dialed. The terminal TU requests the call by sending a CHANNEL REQUEST message to the base station BTS.

2. The base station BTS forwards a channel reservation request to the CHANNEL_REQUIRED access node AN, which begins to retrieve the traffic channel.

3. After the traffic channel has been successfully allocated, the access node AN activates the channel by sending a CHANNEL ACTIVATION message to the base station BTS.

4. The base station BTS acknowledges the successful activation with a CHANNEL ACTIVATION ACK message. Base station BTS

initiates transmission and reception on that channel using the power and timing information received in the CHANNEL ACTIVATION message.

5. After the traffic channel is successfully activated, the access node AN sends an IMMEDIATE ASSIGNMENT COMMAND message to the base station BTS.

6. This message contains an IMMEDIATE ASSIGNMENT - · · v message sent by the BTS to the terminal: '· TU.

! : '· 25 7. Upon receipt of the IMMEDIATE ASSIGNMENT

I «* message terminal TU tunes to the designated traffic channel: ·. and begins to establish a signaling link over the network.

• *]. # · The TU transmits a layer-2 SABM message to the base station • · 'on the BTS 1 traffic channel. The SABM includes a layer-3 service request message.

8. The base station forwards the terminal service request to the AN ESTABLISH

• · • * · In the INDICATION message, includes subscriber status. header identifier TMSI (temporary mobile subscriber identifier).

9. The base station BTS acknowledges the SABM message by transmitting f * ·· to the TU of the UA frame.

10. The access node element looks for the subscriber's L3 address (using TMSI and IMSI) and checks the status of the corresponding V5 interface. If call setup is allowed, the access node AN sends an ESTABLISH message to the local exchange LE.

11. At the same time, the access node AN initiates encryption by sending an ENCRYPTION COMMAND message to the base station BTS. The base station BTS analyzes the command. If encryption is required, the base station BTS activates the demodulator 10 to decrypt.

12. If encryption is used, the base station BTS sends a CIPHERING MODE COMMAND message to the terminal TU.

13-14. The local exchange LE transmits to the subscriber-15 network element AN ALLOCATION message including the time slot used in the V5.2 interface. The access node AN acknowledges by sending the ALLOCATION COMPLETE message to the local exchange LE.

15. Upon receipt of the CIPHERING MODE COMMAND-20 message, the TU shall initiate decryption and decryption using an available encryption key and return the BTS to the base station in encrypted form CIPHERING

I I 1 v MODE COMPLETE message or next message that it

is to be sent. After receiving CIPHERING MODE

i 25 COMPLETE messages (or any correctly encrypted layer

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· '·' 2-frame) base station BTS begins encryption and transmits • · the message transparently to the access node AN.

When the local exchange LE is ready to receive the dialing, it sends an ESTABLISH ACK-30 message to the access node AN. The connection between the access node AN and the local exchange LE is established and the voice path is switched on.

17. The terminal TU initiates call set-up with a T SETUP message containing, for example, the called subscriber's j. 35 number and the call type (speech / data). The subscriber network AN element checks the VLR / HLR database to allow the 9 * ·· / subscriber to make a call. If the correct conditions are met, the M »· M ·« «· 7 105310 access network AN transmits dual tone multi frequency (DTMF) numbers to the local exchange LE (together with V5 messages).

18. After transmitting the numbers, the access node 5 transmits a CALL PROCEEDING message to the terminal (TU) indicating that the call is being processed.

19-22 The channel mode is changed from signaling to speech by a "mode modify" procedure. First, the subscriber network element AN sends a MODE MODIFY message to the base station BTS to change the channel mode. Synchronization with the transcoder begins. Upon receiving the MODE MODIFY ACK message, the access node starts changing channel mode and transmits the CHANNEL MODE MODIFY message to the terminal TU. This command is a transparent support weapon-15 for BTS. After receiving the CHANNEL MODE MODIFY message over the air interface, the terminal TU changes the channel mode from signaling to speech and acknowledges the access node AN by sending a CHANNEL MODE MODIFY ACK message. This message is also transparent to the base station BTS.

20 23-24. The TU is set to speech mode by sending a CONNECT message to the TU. The terminal TU acknowledges with the CONNECT ACK message. The subscriber now hears a ring tone from the local exchange LE.

: 25-26 If the VLR of the subscriber network element: 25 does not recognize the temporary identifier TMSI,

{Entering International Mobile Subscriber Identity IMSI

(international mobile Subscriber identity) with an IDENTIFICATI- • ON message. In response, an IDENTIFICA- • TION RESPONSE message is sent to the TU.

27. The access node AN begins authentication by sending an AUTHENTIFICATION REQUEST message to the terminal TU.

28. The terminal TU sends a calculated response to the access node AN AUTHENTI FI CATION RESPONSE- 35.

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The invention is not limited solely to the above examples, but many modifications are possible within the scope of the inventive idea as defined in the claims.

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Claims (7)

A method for establishing a call in a wireless subscriber network based on a mobile communication technology, wherein the subscriber terminals (TU) are radio-connected to a subscriber network element (AN) and a subscriber network element to a fixed network local exchange (LE) with a standard V5 interface. characterized in that, in order to speed up call set-up, the check functions are performed in the speech mode of the call. A method according to claim 1, characterized in that the subscriber terminals (TUs) 15 are connected to the access node (AN) via a radio connection according to the GSM specification; and performing verification functions including subscriber identity change (TMSI reallocation), subscriber authentication and / or subscriber device 20 identification (IMEI check). A method according to claim 2, characterized in that the subscriber identifier exchange is a TMSI reallocation according to GSM 04.08 4.3.1. The process according to claim 2 or 3. 25, characterized in that the subscriber's authentication • 1 «\\ is in accordance with GSM 04.08 4.3.1: 1 ·. authentication. t Method according to one of Claims 2 to 4, characterized in that the subscriber's device identifier is checked according to GSM 04.08. 4.3.3 IMEI verification. Method according to one of claims 1 to 5, characterized in that the V5 interface is a V5.2 interface according to V standard ETS 300 347-1. i ». : 35 Method according to one of Claims 1 to 5, characterized in that the V5 interface is a V5.1 interface according to ETS 300 324-1. «Il · • · · 1. t« 10 105310