Source: http://www.google.com/patents/US20020054586?dq=6,304,975
Timestamp: 2016-09-27 01:19:16
Document Index: 190569593

Matched Legal Cases: ['arts 14', 'art 14', 'art 16', 'art 14', 'art 16', 'art 14', 'art 16']

Patent US20020054586 - Method and apparatus for transmitting voice data over various types of networks - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsA method for transmitting voice data over various types of networks wherein user data are transmitted via a transmission link of a circuit-switched network and are distributed to data packets and forwarded via a packet transmission network if the user data are typical of voice transmission. If, in contrast,...http://www.google.com/patents/US20020054586?utm_source=gb-gplus-sharePatent US20020054586 - Method and apparatus for transmitting voice data over various types of networksAdvanced Patent SearchTry the new Google Patents, with machine-classified Google Scholar results, and Japanese and South Korean patents.Publication numberUS20020054586 A1Publication typeApplicationApplication numberUS 09/682,183Publication dateMay 9, 2002Filing dateAug 1, 2001Priority dateAug 1, 2000Also published asCN1193554C, CN1452829A, DE50112271D1, EP1305918A1, EP1305918B1, US6879583, WO2002011376A1Publication number09682183, 682183, US 2002/0054586 A1, US 2002/054586 A1, US 20020054586 A1, US 20020054586A1, US 2002054586 A1, US 2002054586A1, US-A1-20020054586, US-A1-2002054586, US2002/0054586A1, US2002/054586A1, US20020054586 A1, US20020054586A1, US2002054586 A1, US2002054586A1InventorsKlaus HoffmannOriginal AssigneeKlaus HoffmannExport CitationBiBTeX, EndNote, RefManPatent Citations (5), Referenced by (8), Classifications (12), Legal Events (5) External Links: USPTO, USPTO Assignment, EspacenetMethod and apparatus for transmitting voice data over various types of networks
DETAILED DESCRIPTION [0034] [0034]FIG. 1 shows a telephone network 12, for example the telephone network of Telecom AG, which is connected to the Internet 10. FIG. 1 shows two parts 14 and 16 of the telephone network 12. Part 14 is located, for example, in Southern Germany and part 16 in Northern Germany. In part 14, a terminal exchange 18 is shown to which a subscriber T1 nA is connected via a transmission line 20; e.g., via an ISDN (Integrated Services Digital Network) connection. The terminal exchange 18 is connected to a transit exchange 24 via an interoffice trunk 22. The transit exchange 24 is, for example, a conventional exchange of the EWSD (digital electronic switching system) type of the Siemens AG company. A transmission link 26 leads from the transit exchange 24 to an interworking unit 28. The transmission link 26 is, for example, a channel of a PCM (Pulse Code Modulation) system which is otherwise used for transmitting voice data between various exchanges. The connections between various exchanges are also called trunks. [0035] A transmission link leads from the transit exchange 24 to another interworking unit 32. The function of the interworking units 28 and 32 will be explained below. [0036] Part 16 of the telephone network 12 contains a transit exchange 34; e.g., of the EWSD type. The transit exchange 34 is connected via an interoffice trunk 36 to a terminal exchange 38 to which a subscriber T1 nB is connected. A transmission link 40 of the transit exchange 34 leads to an interworking unit 42. A further transmission link 44 leads from the transit exchange 34 to an interworking unit 46. The transmission links 40 and 44 are, for example, PCM channels such as are normally used for transmitting voice data between exchanges. The operation of the interworking units 42 and 46 will be explained below. [0037] The telephone network 12 also contains two exchanges 48 and 50 which are further developments of the exchanges of the EWSD type. In addition to the functions of an exchange of the EWSD type, the exchanges 48 and 50 also take over the functions of service-providing computers 52 and 54. These additional functions are below with reference to FIG. 2. Between the exchange 58 and the transit exchange 24, a signaling link 56 can be set up on which the signaling messages are transmitted in accordance with the ISUP (ISDN User Part) protocol. Examples of messages of this protocol will be explained below with reference to FIG. 1 as well. [0038] Between the exchanges 48 and 50, a signaling link 58 can be set up. The signaling messages over this signaling link are also transmitted in accordance with the ISUP protocol. [0039] Information elements are transmitted in a container according to the Q.765 (1998) standard. Between the exchange 50 and the transit exchange 34, a signaling link 60 can be set up on which signaling messages are transmitted according to the ISUP protocol. [0040] Both the telephone network 12 and the Internet 10 are used for transmitting voice data between subscriber T1 nA and subscriber T1 nB. The voice data are transmitted circuit-switched in voice channels in the telephone network 12. In the Internet 10, in contrast, the voice data are transmitted in data packets. The boundary between the telephone network 12 and the internet 10 is indicated by a dashed line 62. [0041] In the interworking units 28, 32, 42 and 46, voice data which are, in each case, received in voice channels are divided to data packets and forwarded into the Internet 10. Data packets with voice data coming from the Internet 10 are depacketized in the interworking units 28, 32, 42 and 46 and forwarded into the telephone network 12 in voice channels. The voice data are coded according to the G.711 standard on the transmission links 26, 30, 40 and 44. [0042] The interworking units 28, 32, 42 and 46 are connected to the Internet 10 in this order via transmission links 64 to 70 so that data packets can be exchanged between interworking units 28, 32, 42 and 46 via the Internet 10. The service-providing computers 52 and 54 are also connected to the Internet 10. Thus, data packets also can be exchanged between the service-providing computers 52 and 54, respectively, and the interworking units 28, 32, 42 and 46, see signaling path 72 and 74, respectively, between the service-providing computer 52 and the interworking unit 28 and between the service-providing computer 54 and the interworking unit 42, respectively. The interworking units 28, 32, 42 and 46 and the service-providing computers 52 and 54 have, in each case, at least one Internet address at which they can be reached in the Internet 10. [0043] [0043]FIG. 2 shows signaling messages for setting up a connection between subscriber T1 nA and subscriber T1 nB. Functional units explained with reference to FIG. 1 have the same reference symbols in FIG. 2. When a call connection is set up between subscriber T1 nA and subscriber T1 nB, the transit exchange 24 generates, according to protocol, a connection set-up message 100, also called IAM (Initial Address Message) message at a time t1. [0044] Among other things, this message contains the complete telephone number of the subscriber T1 nB in the telephone network 12 and the number of a time slot to be used for transmission on the transmission link 26. The connection setup message 100 is transmitted via the signaling link 56. After the connection setup message 100 has been received, a program is executed in the exchange 48, which determines that the Internet 10 can be used for the transmission of the voice data. It is determined that the interworking unit 28 must be utilized as interface between telephone network 12 and Internet 10 on the side of the subscriber T1 nA. A control unit of the exchange 48 causes the service-providing computer 52 to execute the steps necessary for this. [0045] At a time 12 after the time t1, the service-providing computer 52 sends a connection setup message 102 according to the de facto standard RFC2705 to the interworking unit 28 via the signaling path 72. The connection setup message 102 is also called CRCX (Create Connection) message. In the connection setup message 102, the time slot is specified which is to be used for the user data transmission. In addition, the CRCX message contains information on whether a voice connection is affected and whether measures for preventing the transmission of data packets in silence intervals must therefore be made. To transmit this information, a bit is used which is called the “Silence On/Off” bit in the RFC2705 standard. According to the 10 standard, this bit indicates whether silence interval suppression is to be carried out or not. [0046] The interworking unit 28 processes the connection setup message 102 and, as a response, generates a response message 104 at a time t3. The response message 104 confirms reception of the connection setup message 102, on the one hand, and contains, among other things, an Internet address and a port number which can be used for receiving user data for an RTP connection to be set up between the interworking unit 28 and the interworking unit 42 and which is now allocated to the time slot. [0047] The service-providing computer 52 receives the response message 104 and forwards the received Internet address and port number to the control unit of the exchange 48. The control unit of the exchange 48 processes the connection setup message 100 in accordance with the ISUP protocol and generates a connection setup message 106 at a time t4. The connection setup message 106 is also called an IAM message according to ISUP protocol. The connection setup message 106 contains information elements in which the Internet address and the port number are forwarded. These information elements are not specified in the ISUP standard but are transmitted via the signaling link 58 adhering to the ISUP standard. This is also called tunneling. [0048] The exchange 50 receives the connection setup message 106 and also processes the information elements contained in it. On the basis of the content of these information elements or via the circuit identification code (CIC), it is recognized that it is not a usual telephone connection but a telephone connection using the Internet 10 which is to be set up. The exchange 50 determines that it is the interworking unit 42 which is to be the interworking unit to be used on the side of the subscriber T1 nB. In addition, the exchange 50 determines a time slot which will have to 10 be used if the user data transmission between exchanges 50 and 34 is exclusively circuit-switched. This time slot designates a transmission channel of the transmission link 40. The control unit of the exchange 50 causes the service-providing computer 54 to set up an Internet connection via the signaling path 74. At a time t5, the service-providing-computer 54 sends a connection setup message 108 to the interworking unit 42. The connection setup message 108 corresponds to the aforementioned de facto standard RFC 2705 and is also called a CRCX (Create Connection) message. The message 108 contains the Internet address sent by the interworking unit 28 via the exchange 48, and the port number which are to be used for the RTP connection to be set up. In addition, the time slot determined by the exchange 50 is specified in the connection setup message 108. [0049] The connection setup message 108 contains the bit position “Silence On/Off”. A predetermined value in the bit position signals that the interworking unit 42 is to take measures for preventing the transmission of data packets in the Internet 10 in a case of silence intervals. [0050] During the processing of the connection setup message 108 in the interworking unit 42, an Internet address and an as yet unoccupied port number of the interworking unit 42, which can be used for the reception of the user data packets by the interworking unit 28, are determined for the specified time slot. [0051] The interworking unit 42 then sends a response message 110 at time t6 in order to confirm the reception of the connection setup message 108. The response message 110 also contains the Internet address of the interworking unit 42 determined and the port number determined. [0052] The remaining part of the connection setup message 106 is processed in accordance with the ISUP protocol in the exchange 50. During this process, a connection setup message 112 is generated which is 10 transmitted to the transit exchange 34 via the signaling link 60. The connection setup message 112 is also called an IAM (Initial Address Message) message. The connection setup message 112 contains, among other things, the call number of the subscriber T1 nB and the time slot predetermined by the exchange 50. In the transit exchange 34, the connection setup message 112 is processed according to protocol and forwarded to the terminal exchange 38. The terminal exchange 38 calls the terminal of the subscriber T1 nB. [0053] During the processing of the connection setup message 106, after the reception of the response message 110, a response message 114 which is also called an ATM (Application Transport Message) message in accordance with the ISUP protocol, is generated in the exchange 50. The response message 115 contains an information element with the Internet address of the interworking unit 42 and an information element with the port number transmitted by the interworking unit 42. The response message 114 is transmitted to the exchange 48 at a time t8. [0054] The control unit of the exchange 48 extracts the Internet address and the port number from the response message 114 and causes the service-providing computer 52 to forward these connection parameters to the interworking unit 28. [0055] For this purpose, the service-providing computer 52 sends a modification message 116 according to de facto standard RFC 2705 at a time t9. The modification message 116 is also called an MDCX (Modify Connection) message. The modification message 116 contains the Internet address of the interworking unit 42 and the port number of the interworking unit 42, which is to be used for the RTP connection to be set up. [0056] The modification message 116 is processed in the interworking unit 28 and a direct transmission path 118 can be used for transmitting user data between the interworking units 28 and 42 in accordance with the RTP 10 protocol. A response message to the modification message 116, generated by the interworking unit 28, is not shown in FIG. 2. [0057] At a subsequent time t10, the transit exchange 34 generates, according to protocol, a message 120 which is also called an ACM (Address Complete Message) message and signals that all dialing digits have been transmitted in order to connect subscriber T1 nA and subscriber T1 nB. The message 120 is processed by the control unit of exchange 50 in accordance with protocol. At a time t11, the exchange 50 sends an ACM message 122 to the exchange 48 according to the ISUP protocol. The exchange 48 processes the ACM message 122 and, in turn, sends an ACM message 124 to the transit exchange 24. [0058] If the subscriber T1 nB accepts a call, it will be signaled to the transit exchange 34 in accordance with the ISUP protocol. At a time t13, the transit exchange 34 generates a response message 126 which is transmitted to the exchange 50 via the signaling link 60. The response message 126 is also called an ANM (Answer Message) message. On the basis of this message, for example, the call begins to be chargeable. [0059] The response message 126 is processed in the exchange 50 in accordance with the protocol. During this process, a response message 128 is sent to the exchange 48. The exchange 48 generates a response message 130 to the transit exchange 24 at a time t15 on the basis of the response message 128. [0060] The voice data generated by the subscriber T1 nA are transmitted in time slots in part 14 of the telephone network 12 and via the transmission link 26. Between the interworking units 28 and 42, the voice data are transmitted in data packets according to the RTP protocol. On the transmission link 40 and in part 16 of the telephone network 12, the voice data are again transmitted in time slots. The processes in the interworking units 28 and 42 will be explained in 10 greater detail below with reference to FIG. 3. [0061] The method explained with reference to FIG. 2 is used, for example, when other transmission links of the telephone network 12 are used to full capacity and/or when the use of the Internet 10 brings cost advantages for the operator of the exchanges 48 and 50 and, thus, for the subscriber T1 nA as well. [0062] [0062]FIG. 3 shows the steps carried outer in the interworking unit 28 and in the interworking unit 40, respectively, during the conversion of user data from a transmission channel 150 of the transmission link 26 and 40, respectively, into data packets 152 to 160. Time frames R1 to RX+1 are successively transmitted via the transmission link 26 and 40, respectively. Bit positions 0 to 7 designate bits of the data words transmitted in the transmission channel 150. [0063] In time frame R1, a data word which contains the value 0 at bit position zero is transmitted in transmission channel 150. At bit position 1, the value one is transmitted. Bit positions 6 and 7, in each case/ have the value one. Points 162 indicate bit positions between bit positions 1 and 6. The interworking unit 28 evaluates these user data and finds out that these are voice data. For this reason, the data word transmitted in time frame R1 of the transmission 150 is transmitted in the packet body of the data packet 152. In the packet header of the data packet 152, a marker bit 164 is occupied by the value one in order to indicate that further data packets are following. [0064] In a subsequent time frame R2, a data word which contains voice data is also transmitted. For this reason, this data word is transmitted in the packet body of the subsequent data packet 154. A marker bit 166 of the data packet 154 has the value one in order to indicate that further data packets are following. [0065] In a time frame R3, a data word with bit values of zero indicate that now no voice data are transmitted but rather data which are produced in a silence interval. The interworking unit 28 detects this silence interval and transmits the data packet 154 in which the marker bit 168 has the value zero. The value zero indicates that, for the time being, no further data packets will be transmitted. For a relatively long time, e.g. 300 ms, only time frames R4 to RX−1 are received, the user data of which were produced in silence intervals. These time frames are indicated by dots 169. The interworking unit 28 evaluates these user data, associates them with the silence interval and discards them. As a consequence, the data words of time frames R4 to RX−1 are not forwarded in data packets via the Internet 10. [0066] It is only in a time frame RX that a data word is again transmitted which contains voice data. The interworking unit 28 finds out that voice data are transmitted when it checks the user data. For this reason, the data word transmitted in the transmission channel 150 of the time frame RX is transmitted via the Internet 10 in the packet body of the data packet 158. A marker bit 170 of the data packet 158 again has the value one. [0067] In the subsequent time frame RX+1, further voice data are transmitted in the transmission channel 150. For this reason, these voice data are taken from the transmission channel 150 and packetized in the data packet 160. A marker bit 172 of the data packet 160 has the value one. [0068] The data packets 152 to 160 are received in the interworking unit 42. The values of the marker bits 164 to 168 and 170 to 172, respectively, indicate that further data packets must follow, according to the RTP protocol. After the data packet 156 has arrived, the value of zero in the marker bit 168 indicates the silence interval. During this silence interval, the interworking unit 42 does not receive any data packets of the connection explained in FIG. 3. However, user data which are typical of silence intervals are transmitted to the exchange 34 in a transmission channel. [0069] The method steps explained with reference to FIG. 3 will only be carried out if the transmission of voice data has been signaled in CRCX messages with the aid of the bit position “Silence On/Off” by the exchanges 48 and 50, respectively. Otherwise, all incoming user data are packetized in data packets and forwarded via the Internet 10. [0070] In another exemplary embodiment, both interworking units 28 and 42 are controlled from one exchange, for example from exchange 48 or exchange 50. [0071] In another exemplary embodiment, the interworking units 28 and 42 are contained directly in one or two exchanges. In this case, a protocol internal to the exchange can be used for controlling the interworking units 28 and 42. [0072] Although the present invention has been described with reference to specific embodiments, those of skill in the art will recognize that changes may be made thereto without departing from the spirit and scope of the invention as set forth in the hereafter appended claims. 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KG, GERMANYFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SIEMENS AKTIENGESELLSCHAFT;REEL/FRAME:020915/0503Effective date: 20080107Sep 29, 2008FPAYFee paymentYear of fee payment: 4Sep 27, 2012FPAYFee paymentYear of fee payment: 8Nov 19, 2014ASAssignmentOwner name: NOKIA SOLUTIONS AND NETWORKS GMBH & CO. KG, GERMANFree format text: CHANGE OF NAME;ASSIGNOR:NOKIA SIEMENS NETWORKS GMBH & CO. KG;REEL/FRAME:034294/0675Effective date: 20130912RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services