CN100401811C - Method for implement secondary coding-decoding operation service at cross-packet network and media gateway - Google Patents
Method for implement secondary coding-decoding operation service at cross-packet network and media gateway Download PDFInfo
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Abstract
The present invention discloses a method and a media gateway for realizing secondary coding-decoding operation TFO service in packet networks. The media gateway comprises a non TFO state coding and decoding unit, a TFO signaling detection judgment unit, a TFO signaling transparent transmission unit and a compression speech coding and decoding unit. When the media gateway bears and retransmits the data of the packet networks, if the transmission data carries the TFO signaling, the TFO signaling can be transparently transmitted to the opposite end of the packet network for TFO negotiation. When the TFO negotiation is successful, the medial gateway can adopt compression speech coding and decoding determined by both communication sides for extracting compression speech frames which can be transmitted on the packet networks. The present invention can simply and efficiently carry out end-to-end operation of the TFO service passing through the packet network, increase speech quality, reduce bandwidth occupation and reduce the cost of the media gateway.
Description
Technical field
The present invention relates to Tandem Free Operation (TFO, the Tandem FreeOperation) technology in the communication system, relate in particular to method and media gateway that a kind of cross-packet network is realized the Tandem Free Operation business.
Background technology
The TFO technology is in order to solve wireless compressed voice when transmitting on time division multiplexing (TDM, the Time DivisionMultiplex) communication system, because encoding and decoding conversion causes the problem of voice quality damage.The TFO technology refers to consult by in-band signalling, transmits pure pulse code modulation (PCM, Pulse Code Modulation) code stream in the high position of each sampling of TDM carrying, low level transmission TFO signaling and compressed speech frame, to reach following advantage:
(1) improves voice quality: because can reduce by twice encoding and decoding speech conversion.
(2) improve digital signal processor (DSP) disposal ability: because do not need to do real encoding and decoding conversion.
(3) save transmission link: a plurality of compressed voice speech channels can be multiplexing on a TDM time slot.
(4) reduce propagation delay time:, saved the time-delay of encoding and decoding conversion owing to reduced encoding and decoding conversion.
Fig. 1 is for realizing the schematic diagram of TFO in utilizing the digital cellular mobile communication systems of TDM (GSM).Referring to Fig. 1, MS is the mobile subscriber, and TRAU is the encoding and decoding speech unit, be responsible for the conversion between compressed speech frame and the pcm stream, can be positioned in base station controller (BSC, Base StationController) or the mobile switching centre (MSC, Mobile Switch Center).Transmit compressed speech frame between MS and the TRAU, as the GSM-HR encoding and decoding; Between two TRAU, transmit pcm stream by the TDM carrying.Equipment in the path (IPE, In Path Equipment) refers on the TFO path, can discern the TFO business automatically, and the functional entity of energy transparent transmission TFO business.
Pcm stream is meant the encoding and decoding speech of the G.711 form that transmits on TDM; Compressed speech frame is meant the compressed voice code/decode format than G.711 the code/decode format occupied bandwidth is littler.Compressed voice code/decode format commonly used in the gsm system has: GSM_FR, GSM_HR, GSM_EFR, FR_ adaptive multi-rate encoding and decoding (AMR), HR_AMR, OHR_AMR etc.; Compressed voice code/decode format commonly used in the WCDMA system has: UMTS_AMR, and UMTS_AMR_2, FR_AMR-WB, UMTS_AMR-WB, OFR_AMR-WB, OHR_AMR-WB has waited; Compressed voice code/decode format commonly used in the cdma system has: EVRC etc.
When non-TFO, compressed speech frame between two MS need be through the encoding and decoding conversion of two TRAU, to compressed speech frame from left to right, the compressed speech frame that earlier left side MS is sent on first TRAU converts pcm stream to, on second TRAU, again pcm stream is converted to compressed speech frame, is sent to purpose MS.Therefore this calling will can have a strong impact on voice quality through twice encoding and decoding conversion.
When TFO, in the TDM carrying between two TRAU, consult whether can directly pass compressed speech frame earlier with in-band signalling, the content of consulting comprises whether whether the ability of the TRAU at two ends supports to transmit the employed compressed voice encoding and decoding of compressed speech frame and two ends identical, if all be, then consult successfully, if consult successfully then directly to transmit compressed speech frame in the TDM carrying, reception and transmitting terminal are not done encoding and decoding conversion, and voice quality improves; If the merit of failing to consultations then continues through twice encoding and decoding conversion.In addition, if the encoding and decoding of a certain end change then hold consultation again.
Each TDM time slot bandwidth 64Kbps, and the general bandwidth of compressed speech frame is all less than 16Kbps or 8Kbps, the shared bandwidth of TFO in-band signalling is also very little, so the TFO technology utilizes the low level (can form a low bit port by some low levels) of each sampling of TDM time slot to transmit TFO information frame, compressed speech frame or control bit, a high position still is used for transmitting pcm stream.Before TFO consulted successfully, pcm stream was an efficient voice like this; After TFO consulted successfully, compressed speech frame was an efficient voice, has carried out encoding and decoding conversion with regard to not needing.
When using the TDM carrying in wireless systems such as WCDMA, CDMA, the principle of TFO technology is identical.
Fig. 2 is the TFO signaling process figure of an existing concrete TFO srvice instance.Referring to Fig. 2, the signaling that transmits between described media gateway (MGW) 1 and MGW2 all is the TFO signaling, and all signaling messages all are that two equities of sending out send.Concrete message meaning is as follows:
(1) TFO_FILL: the notice opposite end begins TFO.
(2) TFO_REQ (x): compressed speech frame is transmitted with the x encoding and decoding in the request opposite end when TFO.
(3) TFO_ACK (y): the opposite end is replied and can only be transmitted compressed speech frame with the y encoding and decoding.
(4) (z): encoding and decoding are inconsistent for x, y, heavily consult for TFO_REQ_L.
(5) (y, z): reply the opposite end can only be with y or z encoding and decoding for TFO_ACK_L.
(6) TFO_REQ (y) and TFO_ACK (y): both sides consult to use the y encoding and decoding.
(7) TFO_TRANS:TFO consults successfully, begins to transmit compressed speech frame.
(8) TFO_NORMAL:TFO finishes.
Above-mentioned TFO is a kind of communication protocol with interior encode/decode-free operation, also has a kind of communication protocol (TrFO, Transcoder Free Operation) with outer encode/decode-free operation in the prior art.Among the TrFO, network can just utilize out-of-band signalling that the type and the pattern of encoding and decoding are held consultation before call setup, makes the communication two ends use identical encoding and decoding.When the encoding and decoding of gateway are revised, can notify the encoding and decoding of chain of command, so that the encoding and decoding unanimity at two ends by signaling modification opposite end gateway.The TrFO coding/decoding negotiation was finished before carrying is set up, and can guarantee to call out the suitable bearing resource of use.
Along with networks development, in the TDM network, introduced packet transmission networks, for example Internet Protocol (IP) network or atm network.Just the fit applications problem of TFO technology and packet network has appearred in this case.Be that example describes in the GSM network, to introduce NGN IP kernel heart net below:
Fig. 3 is a schematic network structure of introducing NGN IP kernel heart net in the GSM network.Referring to Fig. 3, in the former TDM network, the end-to-end TFO that carries out between two BSC.After introducing IP kernel heart net, MGW equipment is responsible for carrying conversion and the media conversion between TDM and the IP kernel heart net, just pcm stream on the TDM and packet side carrying G.711, phonetic matrix such as AMR changes mutually.In conversion, need to do some optimization processes, for example carry out gain controlling, data are amplified.But, because amplifying its represented meaning of back, the TFO signaling can change, therefore this conversion can cause the damage of TFO signaling; Owing in the IP transmission, may have packet loss and shake, also can cause the damage of TFO signaling in addition, consult so in the TDM of cross-packet network network network, can not directly carry out end-to-end TFO.
In view of this, current several schemes that realize the TFO business in cross-packet network have been proposed.
Prior art one is the solution of 3GPP: because TFO can not pass through MGW and IP network, therefore at the TFO of MGW termination TDM side, transmit compressed speech frame on packet network.Fig. 4 is prior art one a described scheme schematic diagram of realizing the TFO business in cross-packet network.Referring to Fig. 4, this scheme specifically comprises when carrying out end-to-end communication:
(1) at call establishment stage, use the TrFO technology, consult between two MGW of IP packet network, to use identical compressed voice encoding and decoding by the control of the MGCF in the IP packet network.
(2) after call setup is finished, in the TDM carrying, carry out TFO simultaneously between two BSC at two ends and the MGW and consult; If the TFO between a certain end BSC and the MGW consults failure, then the MGW of this end carries out encoding and decoding conversion, and pcm stream is converted to the compressed voice encoding and decoding, but not influencing an other end carries out TFO.
(3) inconsistent in the TFO negotiations process as if the compressed voice encoding and decoding of TFO side and the use of TrFO side, can reselect the compressed voice encoding and decoding.Being new compressed voice encoding and decoding reports the MGCF of chain of command from MGW, consults the compressed voice encoding and decoding used on the IP packet network by TrFO again.
(4) after TFO and TrFO consult successfully, the identical compressed voice encoding and decoding of transmission on TDM network and IP packet network; When the TFO of MGW termination TDM side, only need extract compressed speech frame wherein, do not do encoding and decoding conversion, directly this compressed speech frame of transmission on Packet Based Network.
Prior art one can only be used a kind of encoding and decoding, and not need encoding and decoding conversion by the cooperation of TFO and TrFO technology in end-to-end communication process.
But there is following shortcoming in prior art one:
(1) need TFO and TrFO to be used, the compressed voice frame format that the last TFO of TDM uses must be identical with the compressed voice frame format on the IP packet network, otherwise will carry out the compressed voice encoding and decoding conversion, the signaling capability that just needs to depend on chain of command is consulted again.
(2) require MGW must support encoding and decoding conversion, when non-TFO state (TFO consult successfully before or TFO when consulting failure), requirement MGW carries out the encoding and decoding conversion between pcm stream and the compressed voice encoding and decoding, MGW need support a variety of code decode algorithms so on the one hand, increase the cost and the complexity of gateway, encoding and decoding conversion can cause voice quality to reduce on the other hand.
(3) require MGW to support the TFO termination, MGW need do complicated TFO State Control, initiates and termination TFO in the TDM side, only at packet side transmission compressed speech frame.
Prior art two: the TFO business according to waiting the similar processing mode of data service to handle with fax, is promptly used transparent transmission code/decode format (for example ClearMode code/decode format) transparent transmission TFO on IP network.Adopting the ClearMode code/decode format to carry out transparent transmission is meant: the pcm stream of TDM side, be converted to the G.711 code/decode format transmission on the packet network, transfer process is not used any voice-optimizing method (as gain controlling, silence detection etc.), therefore be equivalent to the TFO signaling of local terminal directly is transparent to the opposite end, carrying out end-to-end TFO consults, on media gateway, the TFO signaling is not done any special processing, thereby realize the TFO business of cross-packet network network.
The shortcoming of prior art two is as follows:
(1) because the ClearMode encoding and decoding generally are to use G.711 to wait the lossless encoding/decoding data message transmission, so ClearMode encoding and decoding occupied bandwidth is too big, is several times of compressed speech frame bandwidth.For example G.711 the bandwidth of 20ms packing is about 100Kbps, and the transmission bandwidth of compressed speech frame AMR 20ms packing approximately has only 40Kbps.
(2) because the service quality of IP network is relatively poor, situations such as packet loss, error code can take place, therefore can influence the TFO signaling and consult successful probability.
Summary of the invention
In view of this, main purpose of the present invention provides the method that a kind of cross-packet network is realized the Tandem Free Operation business, can make the TFO business pass through that packet network is end-to-end to carry out simply and effectively, improving voice quality, and reduces taking bandwidth.
Another object of the present invention provides the media gateway that a kind of cross-packet network is realized the Tandem Free Operation business, can make the TFO business pass through that packet network is end-to-end to carry out simply and effectively, improve voice quality, and reduce, reduce the cost of media gateway the taking of bandwidth.
To achieve these goals, technical scheme of the present invention mainly comprises:
A kind of cross-packet network is realized the method for Tandem Free Operation TFO business, this method in the media gateway at packet network edge when the data of cross-packet network are transmitted in carrying, if carry the TFO signaling in the forwarding data, then this TFO signaling is transparent to the Packet Based Network opposite end and consults to carry out TFO; The compressed voice encoding and decoding that TFO consults successfully then to adopt communication two party to decide through consultation go out compressed speech frame from transmitting extracting data, and transmit on packet network.
The described concrete grammar that this TFO signaling is transparent to the Packet Based Network opposite end is: the data of utilizing the transparent transmission code/decode format to transmit on Packet Based Network to carry described TFO signaling are to the Packet Based Network opposite end.
Described transparent transmission code/decode format is a transparent mode ClearMode code/decode format.
This method further comprises: adopt the redundant transmission mode to transmit described TFO signaling in packet network.
The compressed voice encoding and decoding that described employing communication two party is decided through consultation are from transmitting extracting data and go out compressed speech frame and at the concrete grammar that packet network transmits being: the extracting data compressed speech frame of compressed voice encoding and decoding from being transmitted that the media gateway utilization of the data of cross-packet network is decided through consultation transmitted in described carrying, utilizes this compressed speech frame of bearing protocol carrying transmission in the packet network.
Described method further comprises: after before the TFO or TFO end back or TFO failure, the codec parameters that disposes when adopting call setup is transmitted data.
This method further comprises: when transmitting data in Packet Based Network, transmit leg is indicated the frame format of the data that send in bearing protocol, and the recipient selects corresponding encoding and decoding that the data that receive are transmitted processing according to indicated frame format.
The described concrete grammar of the frame format of the data that send of indicating in bearing protocol is: utilize the frame head information of described bearing protocol to indicate described frame format.
This method further comprises: the data that described media gateway is transmitted are the pure pulse code modulation pcm stream of time division multiplexing tdm system, the receiving terminal media gateway is after receiving the data of coming by the Packet Based Network transmission, according to the frame format of bearing protocol indication, with different encoding and decoding frame conversions be synchronized in the same pcm stream and transmit.
The described concrete grammar that this TFO signaling is transparent to the Packet Based Network opposite end is: described TFO signaling is come out from transmitting extracting data, be transferred to the Packet Based Network opposite end by specialized protocol.
A kind of media gateway that realizes cross-packet network TFO business comprises:
Non-TFO state codec unit is used for when media gateway is in non-TFO state by this non-TFO state codec unit and transmits data and transmit on Packet Based Network;
This media gateway further comprises:
The TFO signaling detects judging unit, and whether be used for detecting the cross-packet network data of being transmitted has the TFO signaling and judge whether TFO consults success;
TFO signaling transparent transmission unit when TFO signaling detection judging unit detects the data that carry the TFO signaling, carries out transparent transmission by this TFO signaling transparent transmission unit with described TFO signaling on Packet Based Network;
The compressed voice codec unit after the TFO signaling detects judgment unit judges and goes out TFO and consult successfully, is transmitted from forwarding extracting data compressed speech frame and by Packet Based Network by this compressed voice codec unit.
This media gateway further comprises the frame format indicating member, be used for adding on bearing protocol when sending data and be used to indicate institute transmit the frame format of the encoding and decoding of data, the frame format of indicating according to bearing protocol when receiving data is called the codec unit of correspondence and is carried out decoding processing.
This media gateway further comprises the PCM converting unit, is used for according to the encoding and decoding frame format indication that receives, and different encoding and decoding frames is changed and is synchronized in the same pcm stream transmit.
Described TFO signaling transparent transmission unit can be the transparent transmission codec unit.
Described transparent transmission codec unit adopts the ClearMode encoding and decoding to carry out transparent transmission.
Described TFO signaling transparent transmission unit also can be the unit be made up of TFO signaling extraction unit and TFO signaling transmission unit, wherein TFO signaling extraction unit is used for from described forwarding data the TFO signaling being extracted, and TFO signaling transmission unit is used for transmitting described TFO signaling to the opposite end on Packet Based Network by the agreement of special use.
The beneficial effect that technical solution of the present invention is brought:
(1) the present invention is with respect to prior art one, because media gateway of the present invention just is transparent to the Packet Based Network opposite end with the TFO signaling, do not need to do encoding and decoding conversion, therefore media gateway can not supported the encoding and decoding conversion function of different-format, for example pcm stream is converted to the encoding and decoding of AMR compressed voice; Can avoid like this because the low problem of voice quality that causes of encoding and decoding conversion, reduce the cost and the complexity of media gateway simultaneously.
(2) the present invention owing to only extract compressed speech frame and transmission after consulting successfully, no longer utilizes ClearMode encoding and decoding transparent transmission with respect to prior art two, therefore can save bandwidth.
(3) with respect to prior art one, the present invention does not rely on the negotiation of chain of command signaling, therefore realizes simple.
(4) with respect to prior art one, because media gateway of the present invention does not need encoding and decoding conversion, only need to detect TFO signaling and transparent transmission and extract compressed speech frame, save the DSP resource with respect to prior art one.
(5), only need to detect the TFO signaling and with the speech frame of ClearMode encoding and decoding transparent transmission band TFO signaling, so the realization of TFO is simple, reduces cost because media gateway of the present invention does not need the TFO signaling that terminates.
(6) among the present invention because of the TFO signaling is done redundant transmission, therefore can resist the packet loss phenomenon in Packet Based Network, improve TFO and consult success rate.
(7) the present invention does not change the function and the flow process of miscellaneous equipment except that media gateway, comprises the TFO operation flow, therefore can continue to use existing resource to greatest extent, reduces implementation cost.
The comparison that table 1 is done for the effect of the present invention and prior art one and prior art two schemes:
| Every passage DSP resource | Every passage carrying bandwidth | Voice quality | |
| The inventive method | Be less than 1MIPS | Little, between compressed speech frame with G.711 between the bandwidth, be slightly larger than the compressed speech frame bandwidth | Any moment can not done any encoding and decoding conversion, and quality is higher |
| Prior art one | Maximum 16MIPS (3GPP 23977 protocol definition values) | Little, the compressed speech frame bandwidth | When non-TFO, to do encoding and decoding conversion, second-rate |
| Prior art two | Be less than 1MIPS | Very big, encoding and decoding bandwidth G.711 | The TFO success rate is subjected to the IP network quality of service impacts, and is second-rate when TFO is unsuccessful |
Table 1
In the table 1, MIPS represents the disposal ability unit of DSP.
In a word, use this invention, media gateway does not need to do encoding and decoding conversion just can support the TFO business, as using G.711 encoding and decoding when the non-TFO, when being arranged, the TFO signaling uses ClearMode encoding and decoding transparent transmission, use during the TFO success and from TDM, extract compressed speech frame, both improved voice quality, save the DSP resource again.
Description of drawings
Fig. 1 is for realizing the schematic diagram of TFO in utilizing the GSM of TDM;
Fig. 2 is the TFO signaling process figure of an existing concrete TFO srvice instance;
Fig. 3 is a schematic network structure of introducing NGN IP kernel heart net in the GSM network;
Fig. 4 is at the prior art one described scheme schematic diagram of realizing the TFO business in cross-packet network;
Fig. 5 is the structure chart of a kind of embodiment of media gateway of the present invention;
Fig. 6 is the schematic flow sheet of a kind of specific embodiment of the method for the invention;
Fig. 7 is the state transition diagram of media gateway of the present invention.
Embodiment
Following specific embodiment with reference to accompanying drawing further specifies the solution of the present invention.
Core scheme of the present invention is: a kind of cross-packet network is realized the method for Tandem Free Operation TFO business, when the media gateway at packet network edge is transmitted the data of cross-packet network in carrying, if carry the TFO signaling in the forwarding data, then this TFO signaling is transparent to the Packet Based Network opposite end and consults to carry out TFO; The compressed voice encoding and decoding that TFO consults successfully then to adopt communication two party to decide through consultation go out compressed speech frame from transmitting extracting data, and transmit on packet network.
At above-mentioned core scheme, the present invention proposes a kind of media gateway that is in the packet network edge, can realize the TFO business of cross-packet network.End-to-end TFO business with TDM net cross-packet network is that example describes herein.Especially the TFO business of striding IP kernel heart net to the calling of GSM with GSM is that example describes, but the present invention is not limited to this application, also can be used for WCDMA to the cross-packet network TFO business of WCDMA system, WCDMA to the cross-packet network TFO business of gsm system, the application scenarios such as cross-packet network TFO business of CDMA-CDMA system, described Packet Based Network can be IP network, also can be the ATM bearer network.
Fig. 5 is the structure chart of a kind of embodiment of media gateway of the present invention.This media gateway should be able to support multiple encoding and decoding speech, referring to Fig. 5, this media gateway comprises:
Non-TFO state codec unit 51 adopts this codec unit to carry out medium and carrying conversion to transmit data when media gateway is in non-TFO state, simultaneously notification frame form indicating member 55 this encoding and decoding frame format of indication in bearing protocol.The concrete encoding and decoding of adopting can be pre-configured, for example G.711 encoding and decoding.
The TFO signaling detects judging unit 52, is used for detecting the type whether data (for example speech frame) from the TDM network have the TFO signaling and judge the TFO signaling, gives TFO signaling transparent transmission unit 53 with detected TFO signaling and handles; Media gateway is non-TFO state when not detecting the TFO signaling; If detect that TFO consults signaling then media gateway enters the TFO negotiation state; TFO consults successful signaling or the transmission of TFO success signaling is finished if detect, and then media gateway enters the TFO success status; If detect that TFO finishes or TFO failed signaling then media gateway enters non-TFO state.
TFO signaling transparent transmission unit 53 is used for that the TFO signaling is transparent to the Packet Based Network opposite end and consults to carry out TFO.Concrete, this TFO signaling transparent transmission unit 53 can directly adopt the described TFO signaling of transparent transmission coding/decoding module transparent transmission, and notification frame form indicating member 55 is indicated the frame format of these transparent transmission encoding and decoding in bearing protocol, as a kind of execution mode, this transparent transmission coding/decoding module specifically can adopt the ClearMode encoding and decoding to carry out transparent transmission, also can utilize other transparent transmission encoding and decoding transparent transmissions (for example G.711 transparent transmission encoding and decoding) certainly; Described TFO signaling transparent transmission unit 53 also can be made up of TFO signaling extraction unit and TFO signaling transmission unit, wherein TFO signaling extraction unit is used for from described speech frame the TFO signaling being extracted, and TFO signaling transmission unit is used for transmitting described TFO signaling to the opposite end on Packet Based Network by the agreement of special use.
Compressed voice codec unit 54, be used for consulting successfully at TFO, when media gateway enters the TFO success status, from the speech frame of being transmitted, extract compressed speech frame, and be transferred to the opposite end by Packet Based Network, and notification frame form indicating member 55 is indicated the frame format of these compressed voice encoding and decoding in bearing protocol.Configurable multiple compressed voice encoding and decoding in this compressed voice codec unit 54, follow-up TFO in-band signalling can negotiate optimum compressed voice encoding and decoding.
Frame format indicating member 55, be used for when sending speech frame, on the employed bearing protocol of media gateway, adding the frame format of the encoding and decoding that are used to indicate institute's transmission voice frames, when receiving speech frame, switch different codec unit and carry out decoding processing according to the frame format Dynamic Selection of bearing protocol indication, for example this bearing protocol can be the real-time transport protocol (rtp) of RFC3267 definition, the encoding and decoding frame format that can transmit on RTP form indication Packet Based Network; Also can use the UP agreement indication encoding and decoding frame format of 3GPP definition.This frame format indicating member 55 can be realized consulting just can dynamically switch encoding and decoding speech in same passage without signaling, indicates the code/decode type of present frame use by the additional information (frame format) of every frame.
Each calling passage in media gateway all adopts said structure to support multiple encoding and decoding speech simultaneously.For example a passage is supported G.711 encoding and decoding, ClearMode encoding and decoding, the encoding and decoding of UMTS_ adaptive multi-rate encoding and decoding (AMR) compressed voice simultaneously, wherein comprise the ClearMode encoding and decoding at least, can think that then this passage has the frame format of 10 kinds of speed, wherein UMTS_AMR has 8 kinds of speed, and G.711 encoding and decoding and ClearMode encoding and decoding are respectively as a kind of speed.When media gateway during, from multiple encoding and decoding, select a kind of (as G.711 encoding and decoding) to carry out data transaction at non-TFO state; When media gateway during, adopt the ClearMode encoding and decoding to carry out data transaction in the TFO negotiation state; When media gateway during, adopt the compressed voice encoding and decoding to carry out data transaction at the TFO success status.Using the sort of encoding and decoding is to determine that by the state of TFO each frame can change.
Fig. 6 is the schematic flow sheet of a kind of specific embodiment of the method for the invention.Referring to Fig. 6, comprising:
Call setup success between the calling/called BSC of step 61, communication mutually.
Step 62, call setup success back media gateway are in non-TFO state, and data are transmitted in the encoding and decoding (for example G.711 encoding and decoding) of disposing when utilizing call setup this moment.
Step 63, calling/called BSC initiate side as the TFO signaling, initiate the TFO signaling.
Step 64, media gateway detect in the speech frame of being transmitted whether carry the TFO signaling in the TDM side, if media gateway detects the TFO signaling, then execution in step 65.
The TFO termination mode difference of the present invention and 3GPP definition is: have only initiation and the terminating end of calling/called BSC as the TFO business, the end-to-end TFO that carries out consults, the media gateway TFO that initiatively do not initiate and terminate.The detection method of TFO signaling is existing definition in 3GPP 28062 agreements, is exactly the frame format by definition substantially, and each frame all can be indicated TFO data or TFO signaling.Press protocol definition, first TFO message is TFO_FILL, and the equipment that is used on the notification call path begins the TFO process, and the success of TFO and failure are determined by the signaling negotiation state.
Step 65, media gateway are transparent to the TFO signaling opposite end of IP network.
In this step 65, concrete transmitting method can have two kinds: first kind, use the ClearMode encoding and decoding speech frame that carries the TFO signaling to be transparent to the opposite end of IP network, and the frame format of this speech frame of indication is the ClearMode encoding and decoding in bearing protocol, according to ClearMode encoding and decoding indicated in the bearing protocol speech frame is handled after IP network opposite end media gateway is received.Second kind, the TFO signaling is extracted from described speech frame, give the IP network opposite end by the protocol transmission of special use, at this moment speech frame is not necessarily leaveed no choice but ClearMode encoding and decoding transmission, and also available other encoding and decoding are transmitted.
When the media gateway of opposite end after the IP side is received TFO signaling and speech frame, be converted into pcm stream and and other encoding and decoding frame synchronization in same pcm stream, then pcm stream is transferred to opposite end BSC on TDM.In this way, described TFO signaling just can be transferred to opposite end BSC.Herein because the encoding and decoding of each frame may be different, but the increasing progressively continuously of their time stab information, therefore need carry out different frame synchronously.For example first frame of media gateway reception is the TFO signaling of ClearMode encoding and decoding transmission, and time stamp is 100ms; Second frame is the AMR compressed speech frame, and time stamp is 120ms, and then media gateway leaves them continuously in the TFO frame of pcm stream and gets final product.
In step 65,, in the process of transparent transmission TFO signaling, adopt this TFO signaling of redundant transmission techniques transparent transmission for guaranteeing TFO signaling transmission reliability.For example can use RFC2198 redundant frame mode, come redundant transmission ClearMode encoding and decoding frame, RFC2198 carries last RTP content of message in each IP bearing message (being the RTP message) so that last RTP message is when losing on IP network, can with a back message with redundant frame remedy.
When detecting TFO signaling and this TFO signaling, media gateway (presses protocol definition for consulting successful signaling, TFO_TRANS denoting signaling TFO consults successfully) time, need to detect the agreed optimal compression encoding and decoding speech of calling and called that wherein carries, and in execution of step 65 with after this TFO signaling is carried out transparent transmission, enter TFO and consult successful state, this moment, media gateway needed execution in step 66.
After step 66:TFO consults successfully, calling/called BSC utilizes the low level transmission compressed speech frame of PCM stream in TDM, this moment, media gateway utilized detected agreed optimal compression encoding and decoding speech to extract the compressed speech frame of this coding in the PCM of TDM side stream speech frame, and transmitted the compressed speech frame that extracts by RTP on IP network; In RTP, indicate the speech frame form (being the encoding and decoding of described optimum) of this compressed speech frame simultaneously; When the opposite end media gateway is received compressed speech frame, utilize the optimum edit code of bearing protocol indication that compressed speech frame is carried out encoding and decoding and handle, and be converted to PCM stream and be transferred to opposite end BSC by TDM.
When media gateway detects TFO signaling and this TFO signaling is TFO when finishing signaling or TFO and consulting failed signaling, and execution of step 65 is to carry out transparent transmission to this TFO signaling, and execution in step 67 afterwards.
Step 67: media gateway enters non-TFO state, and the state when promptly returning to call setup returns step 62.
Among the present invention, media gateway is switched code/decode type according to current state, and uses the dynamic switching of bearing protocol indication encoding and decoding speech.For example if used G.711 encoding and decoding originally, switch to the ClearMode encoding and decoding after, need in bearing protocol, indicate the change of code/decode format.Specifically can in RTP frame or UP bearing protocol, should indicate encoding and decoding speech and frame format, but be not limited to this two kinds of forms.
If using the AMR of RFC3267 definition is the carrying transmission methods of compressed voice encoding and decoding on RTP, needs that then CMR field is wherein carried out expanded definition and indicate frame format.In the RFC3267 agreement, definition CMR field is used to indicate the frame type of carrying, and wherein 0-7 represents 8 kinds of speed of AMR encoding and decoding, the quiet frame of 8 expressions, and 15 expression general formats, 9-14 reserves.Increased by two kinds of frame formats among the present invention, can be defined as CMR=9 and represent G.711 encoding and decoding frame format, CMR=10 represents ClearMode encoding and decoding frame format.
By above flow process, media gateway has three main states: non-TFO state (comprising initial state), TFO negotiation state (being TFO signaling transparent transmission state), TFO success status (promptly transmitting the compressed voice frame state).Media gateway is moved according to detected TFO signaling driving condition, different conditions uses different medium encoding and decoding transformats, switching between these code/decode formats is level and smooth, as former frame is ClearMode 20ms packing transparent transmission frame, next frame can be an AMR 20ms packing frame format, can distinguish frame type by the CMR field of RTP head.
Fig. 7 is the state transition diagram of media gateway of the present invention.Referring to Fig. 7:
(1) after non-TFO state is meant call setup, also do not begin TFO negotiations process or TFO end or failure, the perhaps state of TFO step-out; At non-TFO state, the parameters of stipulating during by call setup such as encoding and decoding are carried out medium and carrying conversion.
(2) the TFO negotiation state is meant and has detected TFO signaling transmission, must pass through the TFO signaling from the IP network the state of opposite end; All to move to this state in any state-detection to the TFO signaling; In the TFO negotiation state, can use ClearMode to carry out encoding and decoding transparent transmission TFO signaling, monitor the TFO negotiations process simultaneously, TFO consults failure and changes non-TFO state over to, and TFO consults successfully or finishes in the transmission of TFO success signaling, changes the TFO success status over to.
(3) after the TFO success status refers to that TFO consults successfully, only need the state that extracts compressed speech frame and transmit from low level at IP network.At the TFO success status, except that extract and the transmission compressed speech frame, also need to detect the TFO signaling and whether the TFO state normal, when the TFO abnormal state, transfer to non-TFO state.
In addition, under abnormal conditions, do not support TFO, two ends not to have identical encoding and decoding, TFO signaling message unusual optimization process such as to lose not within stated range of the present invention in Packet Based Network as an end.
The above; only for the preferable embodiment of the present invention, but protection scope of the present invention is not limited thereto, and anyly is familiar with the people of this technology in the disclosed technical scope of the present invention; the variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.
Claims (16)
1. a cross-packet network is realized the method for Tandem Free Operation TFO business, it is characterized in that, when the media gateway at packet network edge is transmitted the data of cross-packet network in carrying, carry the TFO signaling, then this TFO signaling is transparent to the Packet Based Network opposite end and consults to carry out TFO if transmit in the data; The compressed voice encoding and decoding that TFO consults successfully then to adopt communication two party to decide through consultation go out compressed speech frame from transmitting extracting data, and transmit on packet network.
2. realize the method for Tandem Free Operation TFO business according to the described cross-packet network of claim 1, it is characterized in that the described concrete grammar that this TFO signaling is transparent to the Packet Based Network opposite end is: the data of utilizing the transparent transmission code/decode format to transmit on Packet Based Network to carry described TFO signaling are to the Packet Based Network opposite end.
3. cross-packet network according to claim 2 is realized the method for Tandem Free Operation TFO business, it is characterized in that described transparent transmission code/decode format is a transparent mode ClearMode code/decode format.
4. cross-packet network according to claim 1 is realized the method for Tandem Free Operation TFO business, it is characterized in that this method further comprises: adopt the redundant transmission mode to transmit described TFO signaling in packet network.
5. cross-packet network according to claim 1 is realized the method for Tandem Free Operation TFO business, it is characterized in that, the compressed voice encoding and decoding that described employing communication two party is decided through consultation are from transmitting extracting data and go out compressed speech frame and at the concrete grammar that packet network transmits being: the extracting data compressed speech frame of compressed voice encoding and decoding from being transmitted that the media gateway utilization of the data of cross-packet network is decided through consultation transmitted in described carrying, utilizes this compressed speech frame of bearing protocol carrying transmission in the packet network.
6. cross-packet network according to claim 1 is realized the method for Tandem Free Operation TFO business, it is characterized in that, described method further comprises: after before the TFO or TFO end back or TFO failure, the codec parameters that disposes when adopting call setup is transmitted data.
7. realize the method for Tandem Free Operation TFO business according to each described cross-packet network of claim 1 to 6, it is characterized in that, this method further comprises: when transmitting data in Packet Based Network, transmit leg is indicated the frame format of the data that send in bearing protocol, the recipient selects corresponding encoding and decoding that the data that receive are transmitted processing according to indicated frame format.
8. cross-packet network according to claim 7 is realized the method for Tandem Free Operation TFO business, it is characterized in that the described concrete grammar of the frame format of the data that send of indicating is: utilize the frame head information of described bearing protocol to indicate described frame format in bearing protocol.
9. cross-packet network according to claim 7 is realized the method for Tandem Free Operation TFO business, it is characterized in that, this method further comprises: the data that described media gateway is transmitted are the pure pulse code modulation pcm stream of time division multiplexing tdm system, the receiving terminal media gateway is after receiving the data of coming by the Packet Based Network transmission, according to the frame format of bearing protocol indication, with different encoding and decoding frame conversions be synchronized in the same pcm stream and transmit.
10. cross-packet network according to claim 1 is realized the method for Tandem Free Operation TFO business, it is characterized in that, the described concrete grammar that this TFO signaling is transparent to the Packet Based Network opposite end is: described TFO signaling is come out from transmitting extracting data, be transferred to the Packet Based Network opposite end by specialized protocol.
11. a media gateway that realizes cross-packet network TFO business comprises:
Non-TFO state codec unit is used for when media gateway is in non-TFO state by this non-TFO state codec unit and transmits data and transmit on Packet Based Network;
It is characterized in that this media gateway further comprises:
The TFO signaling detects judging unit, and whether be used for detecting the cross-packet network data of being transmitted has the TFO signaling and judge whether TFO consults success;
TFO signaling transparent transmission unit when TFO signaling detection judging unit detects the data that carry the TFO signaling, carries out transparent transmission by this TFO signaling transparent transmission unit with described TFO signaling on Packet Based Network;
The compressed voice codec unit after the TFO signaling detects judgment unit judges and goes out TFO and consult successfully, is transmitted from forwarding extracting data compressed speech frame and by Packet Based Network by this compressed voice codec unit.
12. the media gateway of realization cross-packet network TFO business according to claim 11, it is characterized in that, this media gateway further comprises the frame format indicating member, be used for adding on bearing protocol when sending data and be used to indicate institute transmit the frame format of the encoding and decoding of data, the frame format of indicating according to bearing protocol when receiving data is called the codec unit of correspondence and is carried out decoding processing.
13. the media gateway of realization cross-packet network TFO business according to claim 12, it is characterized in that, this media gateway further comprises the PCM converting unit, is used for according to the encoding and decoding frame format indication that receives, and different encoding and decoding frames is changed and is synchronized in the same pcm stream transmit.
14. the media gateway of realization cross-packet network TFO business according to claim 11 is characterized in that, described TFO signaling transparent transmission unit is: the transparent transmission codec unit.
15. the media gateway of realization cross-packet network TFO business according to claim 14 is characterized in that, described transparent transmission codec unit adopts the ClearMode encoding and decoding to carry out transparent transmission.
16. the media gateway of realization cross-packet network TFO business according to claim 11, it is characterized in that, described TFO signaling transparent transmission unit is: the unit of being made up of TFO signaling extraction unit and TFO signaling transmission unit, wherein TFO signaling extraction unit is used for from described forwarding data the TFO signaling being extracted, and TFO signaling transmission unit is used for transmitting described TFO signaling to the opposite end on Packet Based Network by the agreement of special use.
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|---|---|---|---|---|
| CN101282284B (en) * | 2007-04-02 | 2011-08-10 | 中兴通讯股份有限公司 | Gateway-across dual-tone multi-frequency conveying method and apparatus |
| CN101296205B (en) * | 2007-04-24 | 2011-04-20 | 华为技术有限公司 | Method, equipment and system for implementing transparent transmission in IP network or hybrid network |
| CN101656735B (en) * | 2009-09-11 | 2013-02-13 | 中兴通讯股份有限公司 | Code flow processing method and device in communication link |
| CN101742560A (en) * | 2009-11-20 | 2010-06-16 | 华为技术有限公司 | Data transmission method, data transmission device and network system |
| CN102378137B (en) * | 2010-08-11 | 2014-08-06 | 中国移动通信集团公司 | Coding and decoding network transparent transmission method, device thereof and system thereof |
| CN102843731B (en) * | 2011-06-22 | 2017-10-20 | 中兴通讯股份有限公司 | TFO termination and system applied to wireless communication system |
| CN103167561B (en) * | 2011-12-08 | 2018-02-23 | 中兴通讯股份有限公司 | TFO processing method and processing device |
| EP2798790B1 (en) * | 2011-12-30 | 2018-04-25 | Net Insight Intellectual Property AB | Compression method for tdm frames in a packet network |
| CN103796243B (en) * | 2012-10-30 | 2017-04-05 | 中兴通讯股份有限公司 | TFO configuration parameters transmission method and system |
| CN103871415B (en) * | 2012-12-14 | 2017-08-25 | 中国电信股份有限公司 | Realize the method, system and TFO conversion equipments of different systems voice intercommunication |
| CN103874129B (en) * | 2012-12-18 | 2017-09-12 | 中国电信股份有限公司 | The method and system of complete IP network different systems voice intercommunication |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1364368A (en) * | 1999-07-09 | 2002-08-14 | 诺基亚公司 | Method for transmitting coding information over packet data network |
| US6574469B1 (en) * | 2000-05-09 | 2003-06-03 | Telefonaktiebolaget L M Ericsson (Publ) | System and method of minimizing the number of voice transcodings during a conference call in a packet-switched network |
| US6785276B1 (en) * | 2000-07-25 | 2004-08-31 | Telefonaktiebolaget Lm Ericsson | System for tandem free operation in packet based communication |
| CN1553723A (en) * | 2003-06-08 | 2004-12-08 | 华为技术有限公司 | Method for realizing interconnection of mobile communication network |
-
2005
- 2005-11-15 CN CNB2005101232543A patent/CN100401811C/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1364368A (en) * | 1999-07-09 | 2002-08-14 | 诺基亚公司 | Method for transmitting coding information over packet data network |
| US6574469B1 (en) * | 2000-05-09 | 2003-06-03 | Telefonaktiebolaget L M Ericsson (Publ) | System and method of minimizing the number of voice transcodings during a conference call in a packet-switched network |
| US6785276B1 (en) * | 2000-07-25 | 2004-08-31 | Telefonaktiebolaget Lm Ericsson | System for tandem free operation in packet based communication |
| CN1553723A (en) * | 2003-06-08 | 2004-12-08 | 华为技术有限公司 | Method for realizing interconnection of mobile communication network |
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