CN1375146A - Method and apparatus supporting TDD/TTY modulation over vocoded channels - Google Patents
Method and apparatus supporting TDD/TTY modulation over vocoded channels Download PDFInfo
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- CN1375146A CN1375146A CN00811248A CN00811248A CN1375146A CN 1375146 A CN1375146 A CN 1375146A CN 00811248 A CN00811248 A CN 00811248A CN 00811248 A CN00811248 A CN 00811248A CN 1375146 A CN1375146 A CN 1375146A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/08—Arrangements for detecting or preventing errors in the information received by repeating transmission, e.g. Verdan system
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- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10L—SPEECH ANALYSIS OR SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING; SPEECH OR AUDIO CODING OR DECODING
- G10L19/00—Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis
- G10L19/005—Correction of errors induced by the transmission channel, if related to the coding algorithm
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M1/00—Substation equipment, e.g. for use by subscribers
- H04M1/72—Mobile telephones; Cordless telephones, i.e. devices for establishing wireless links to base stations without route selection
- H04M1/724—User interfaces specially adapted for cordless or mobile telephones
- H04M1/72475—User interfaces specially adapted for cordless or mobile telephones specially adapted for disabled users
- H04M1/72478—User interfaces specially adapted for cordless or mobile telephones specially adapted for disabled users for hearing-impaired users
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W48/00—Access restriction; Network selection; Access point selection
- H04W48/08—Access restriction or access information delivery, e.g. discovery data delivery
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W72/00—Local resource management
Abstract
A method used to encode/decode a low activity communication signal - such as a Baudot tone - for transmission over a telecommunications system (100). The telecommunications system (100) may include any number of wireless links. Once the system (100) is noticed that a low activity signal needs to be transmitted, each vocoder used in the system (100) to encode/decode the signal performs a unique encoding/decoding process. In one embodiment, frames containing errors adversely affecting a signal are delivered to the vocoder and the 'soft bits' contained therein are used to determine the original signal transmitted. In another embodiment, encoding of the signal may include encoding the signal using redundancy with the encoded signal being spread across multiple vocoder frames.
Description
Background of invention
I. invention field
The present invention relates generally to deaf-mute's communicator (TDD) or text phone yoke (TTY) field, relate in particular to the improvement that in communication system, can transmit the standard vocoder work of TDD/TTY signal reliably.System comprises Radio Link.
II. description of related art
The communication terminal that the people of many deaf-mutes or hearing difference uses special configuration and relates to can communicate them on standard phone line.This device is called deaf-mute's communicator (TDD) or text phone yoke (TTY), in this application with its unified TDD that is called.Typically, TDD comprises a keyboard and a display, is connected in telephone set through modem (modulator-demodulator).Modulator-demodulator is contained in the TDD or is directly connected in telephone wire or is coupled to normal telephone bandset by acoustic coupler.TDD can be by the coding tone means on the telephone wire information sent to another TDD that is connected by another modulator-demodulator on the telephone wire other end.These tones are called low activity communication, because frequency keeps relative constant with amplitude envelops.
Extensively the code and the agreement of custom use are specificity code and agreement to TDD communication.Be called fight many code-group and communication protocol (TDD agreement) many deaf-mute's communicators based on machinery or electromechanical assembly but not the electronic installation epoch with historical development.Therefore, the TDD agreement makes up at one group of restriction (no longer relevant with current device).These restrictions cause the communication network that produces a kind of code agreement and user who works and device under this agreement, and this agreement goes out of use a bit.
Traditionally, TDD communication is carried out under 50 bauds (some national 45.5 baud), represents per second to transmit 6 characters.Can add higher baud rate for other agreements of TDD communication usefulness now, as the multi-protocols of fighting of ASCII (American Standard Code information exchange) and enhancing.However, common TDD communication character group is made up of 5 long characters.Letter in these character simulation alphabets, here, a word or a kind of thought represented in each letter.Before transmission character and Overhead position are divided in groups, every group of position to be transmitted here has a duration or unit interval, equals 22 milliseconds.For example, under traditional TDD agreement, a group position to be transmitted comprises 8: start bit (source or zero-bit), 5 represents the position of character and at least one 1/2 again, the halt of sign transmission group.
Compare with modern telecommunication systems, TDD sends and takes place with the snail step pitch.Bigger problem is that the TDD signal comes down to constant.These monotone signals are at a slow speed sending with unusual two-forty in the digital communication system of higher activity signal, especially can produce great calamity in comprising the telecommunication system of Radio Link.An example of this telecommunication system is code division multiple access (CDMA) system with a large amount of wireless subscriber units.Each subscriber unit has a transceiver and transponder or the land station that is called the sub-district communicate in system via satellite.Each sub-district comprises a physics station that is called the base station.The sub-district cover limited geographic area and through mobile switching centre to transmit the calling of carrying on the subscriber unit from communication network.When the user moved in the geographic region of a new sub-district, the transmission of customer call can finally be made by this new sub-district by the process that is called " handover ".
Subscriber unit generally is called cell phone, launches a signal, and this signal is received by the base station.Signal is relayed to mobile switching centre, and the latter passes the signal to the PSTN (PSTN) that comprises telephone wire or other subscriber units.Similarly, signal can be transmitted into subscriber unit through base station and mobile switching centre from PSTN.
Interface between subscriber unit and the base station is called air interface.Telecommunications industry association (TIA) provides the standard of the CDMA call treatment on the interface aloft, and exercise question is " mobile radio station-base station compatibility standard of IS-95 dual mode wideband spread-spectrum cellular system ".The appendix of IS-95 provides as telecommunication service communique (TSB).Standard I S-95+TSB74 is included in the regulation of service negotiation on the air interface, introduces by reference here.
Service negotiation is to succeed in sending up any communication on digital communication system, the key of especially low activity communication.A problem of modern system (comprising said system) is, vocoder-a kind of in system, use with speech or the TDD analog signal is encoded to digital signal and with the device of digital signal decoding as speech or TDD analog signal, handling monotone signal and the difficulty aspect the slow rate of TDD agreement indication in fact.In current system, then may be treated to that background noise or signal disturb and out in the cold by vocoder as the low activity signal of communication of TDD communication.
What need is easily the present invention to be integrated in the existing communication system, can reduce FER (Floating Error Rate) by calling the agreement that vocoder will use during the transmission of low activity signal of communication.
The present invention should be compatible mutually with the aerogram modulating system, as cdma system, serves a large amount of system users.The more sound discussion of cdma system that uses in multi-address communication system and technology can be 4 in the patent No., 901,307 exercise question is seen in the United States Patent (USP) of " utilizing the spread spectrum multiple access communication system of satellite or land transponder ", this application has transferred assignee of the present invention, introduces by reference at this.In addition, the present invention also should be compatible mutually with other modulating systems and the technology used in the communication system of other types, as time division multiple access (TDMA), frequency division multiple access (FDMA), and amplitude modulation(PAM) (AMPS) scheme.
Brief summary of the invention
Broadly, the modulation that the present invention relates to utilize code signal to communicate by letter with the low activity of the telecommunication system that increases transmitted power level.More particularly, the present invention relates to use and encode specially, decode on the low activity signal of communication or the two makes the FER (Floating Error Rate) that transmits reduce to minimum method.The present invention also provides the decoding to low activity signal by watching " the soft position " that be included in the error frame or in the frame adjacent with error frame attentively, attempts to determine the content of primitive frame.
The some embodiments of the invention that disclose provide unique coding/decoding method for the TDD signal that utilizes the standard code protocol code.In one embodiment, decoder can be containing the most probable sound sign indicating number coded frame that the frame (error frame) that sends mistake is compared with the sound sign indicating number coded frame of oneself know the TDD signal and determined emission.In another embodiment, decoder can look back adjacent frame with determine emission but the most probable sound sign indicating number coded frame that received with mistake.In another embodiment, decoder can be improved to and comprise Signal Booster or transponder, the corrupt bits before being applied in coding/decoding method on the frame emission in " cleaning " frame emission.Although TDD communication is discussed in whole the application, is to be understood that and utilizes the present invention can launch any slow or low activity communication.
But another embodiment of the present invention provides decoding discussed above calls the vocoder parameter that is different from the standard vocoder parameter.When receiving the TDD signal, encoder switches to " the odd encoder pattern of fighting ", and the notice decoder protocol changes, and uses the channel code redundancy further to improve the chance of definite correct TDD signal that is transmitted of decoder, even it is included in the bad frame.This form of the present invention is separately better with space interval, therefore is easier to distinguish vocoder " signature " the alternate standard vocoder parameter of tone.
Another form utilization redundancy of the present invention provides TDD signal encoding in the vocoder frame, but coding carries out on several vocoder frames.To be inserted between information on " N " frame, thereby even a frame is lost, decoder can extract necessary information to determine the content of lost frames from consecutive frame.
Another form of the present invention provides a kind of low-cost high-efficiency system that above-mentioned Code And Decode method of the present invention is combined with the method for control transmitted power level.The design that improves mobile radio station internal standard vocoder chipset is expensive, and this can hinder the enforcement of above-mentioned Code And Decode method.Yet, can implement a kind of communication system, wherein in the base station of system, use said method, but in mobile radio station, do not use.Utilize the method for control transmitted power level, can make from the base station to the mobile radio station in not the FER (Floating Error Rate) of the low activity signal of communication of improved vocoder reduce to minimum.
The present invention provides many advantages for its user.An advantage is to utilize the digital transmission medium emission TDD message with Radio Link.Another advantage is the TDD device can be connected to mobile device or subscriber unit, as digital cell phone, is connected to telecommunication system by Radio Link.The present invention also provides many other advantages and benefit, and after describing in detail below comment is of the present invention, these advantages and benefit will become clearer.
The accompanying drawing summary
Considered the following detailed description and in conjunction with the accompanying drawings after, features, objects and advantages of the invention will become more obvious to this area professional and technical personnel, the similar parts of similar Ref. No. sign in whole accompanying drawing, wherein:
Figure 1A is according to the hardware component of the telecommunication system of the adding Radio Link of one embodiment of the invention and interconnective block diagram.
Figure 1B is the block diagram according to the vocoder that is coupled to the prior art notifying device that can implement Code And Decode method of the present invention of one embodiment of the invention.
Fig. 2 illustrates according to the employed typical prior art TDD communicator of one embodiment of the invention.
Fig. 3 illustrates the traffic channel frame format of the employed speed group 1 of rate changeable vocoder.
Fig. 4 is the flow chart according to the method for one embodiment of the invention.
Fig. 5 illustrates the block diagram according to the radio telecommunications system of one embodiment of the invention configuration.
Fig. 6 illustrates the block diagram according to the radio telecommunications system of one embodiment of the invention configuration.
Fig. 7 is the flow chart of the method for transmitted power level between control base station and the mobile radio station.
The detailed description of selected embodiment
Fig. 1 to 7 illustrates the example of the whole bag of tricks of the present invention and device aspect.For convenience of explanation, rather than attempt to impose any restrictions, these examples are to describe in the context of TDD communicator, and the TDD communicator is attached to the digital communication system that adds Radio Link, below will describe one of them example.
Hardware component and interconnecting
Fig. 1 illustrates and comprises Radio Link and as a kind of physical telecommunication system 100 of the TDD communicator (TDD) 200 that uses among the present invention.As what be shown specifically among Fig. 2, TDD generally includes keyboard and display, is connected to telephone set through modem (modulator/demodulator).Modulator-demodulator is contained among the TDD, or is directly connected to telephone wire or is coupled to common telephone bandset by acoustic coupler.TDD can send to another TDD with the information on the telephone wire by the means of coding tone, and the TDD102 described in Fig. 1 connects at the other end of the line by another modulator-demodulator.
In utilizing the digital communication system of Radio Link, TDD200 can be coupled in the telecommunication system 100 subscriber unit 104 in order to transmitting and receiving signal.The exemplary embodiment of subscriber unit 104 is digital signal phones, and the Q-800 as being made by high pass (Qualcomm) joint-stock company is commonly referred to cell phone.Subscriber unit 104 shown in Fig. 1 comprises notifying device 106, is coupled to the circuit of subscriber unit 104 with communication mode.Can rigid line 108 TDD 200 be connected to subscriber unit 104 through notifying device 106, perhaps can the operative installations port.The application number that the example of this notifying device and device port was submitted on July 13rd, 1998 is 09/114,344 exercise question discloses in the U.S. Patent application of " setting up the method and apparatus of TDD/TTY business on sound sign indicating number encoding channel ", this application has transferred assignee of the present invention, introduces by reference at this.
Device port can be configured to receive the low activity communicator annex such as connector, connector or receiver.These projects are normally used for connecting telephone set and computer equipment now, are easy to obtain from electronics supplier there.To be connected to the subscriber unit 104 of telecommunication system 100 with the device port interface of annex such as the low activity communicator (not shown) of TDD 200 with communication mode.Device port allows information to exchange between low activity communicator and subscriber unit 104.No matter whether operative installations port or rigid line, notifying device 106 allows the emission of reporting system 100TDD signal demands.
Get back to Fig. 1, after notifying device 106 receives low activity signal of communication, handle by 104 pairs of signals of subscriber unit.Fundamentally, produce the signal of emission, it comprises the information that is included in the low activity signal.Because notified telecommunication system 100 launching low activity signal, but system is suitable for guaranteeing to take place the cryptography emission.For example, the analog signal that receives from analog circuit 228 shown in Fig. 2 then stands signal or " speech " processing usually, comprises signal digitalized, setting power level are taken place to prevent signal fadeout during sending, compressed signal and filtering.These functions can be undertaken by the circuit (not shown) of the subscriber unit 104 that comprises vocoder.According to the signal that receives, the business in the telecommunication system 100 can dynamically be determined and confer to rate changeable vocoder (being commonly referred to as vocoder in this application), so that succeeding in sending up and decoding of signal to be provided.This is conferred and relates to the value of setting up a plurality of parameters, speed, transmitting power and the compress technique that should use as vocoder.The more fully discussion of the processing that transmits in the relevant telecommunication system can be found in the standard TIA/EIA/IS-95-A of Electronic Industries Association, exercise question is that " mobile radio station-base station compatibility standard of dual mode wideband spread-spectrum cellular system " (is called ' IS-95 '), here introduce by reference, other emission standards, comprising the standard vocoder agreement, also is that this area institute is well-known.
Yet, when activity signal is hanged down in reception, the signal that vocoder can be identified as signal noise, time-out or not wish to launch.Simply, vocoder does not also know that what business using, because it can not discern the low activity signal of reception.Transmitting low activity signal by reporting system 100, vocoder will be set up the possible best emission and the required business of decoding that guarantees this signal.
At treated low activity signal of communication and after having determined business, can on Radio Link 114, utilize antenna 112 to transmit.Digitized signal is received by another antenna 116 of long-range place (as base station 118), and is handled by the base station circuitry (not shown) that comprises vocoder 120.The various base station circuitry configurations of telecommunication system are that this area institute is well-known, and further understanding can be found in above referenced TIA/EIA/IS-95.After reception,, reflect that the low activity signal of information in the low activity signal that is included in emission can be delivered to low activity device 102 through communication link 120 by processing signals.Second notifying device 106 shown in the figure and base station 106 couplings.This provides low activity signal to transmit from low activity communicator 102 and turns back to TDD communicator 200.
Shown in Fig. 2 is the schematic block diagram of the circuit of typical TDD device 200, or the standard or the TDD of enhancing, carries out work according to the present invention.In the TDD of Fig. 2 device 200, a keyboard is provided, the user can arrive wherein by inputting digital character.The discharging chain of keyboard is received processor 204, and the latter's effect is that controlling packet is contained in the circuit element among Fig. 2.Processor 204 receives or the character of emission also is presented on the display 206.Randomly, the identical characters of reception or emission can be reappeared on the device such as printer 208.Some TDD device can not have printer, although standardized TDD has certain visual display, thereby makes the user can see the character of being keyed in and receiving.Therefore the function of keyboard 202 is data character input sources to processor, and any one or the two effect is the local destination of data flow character in display 206 and the printer 208.
Be connected to the telephone keyboard 220 in addition of processor 202 among Fig. 2, its allows to import telephone numbers by telecommunication system 100 by processor 202 by dialing.Standard telephone mobile phone 224 rests on the carriage 226, and it is equipped with the switch (not shown), and whether indication mobile phone 224 is using, and therefore removes from carriage 226.
Although above specific descriptions have benefited from the those of ordinary skill of this disclosure and will discern, device discussed above can be embodied in the heteroid telecommunication system, and without prejudice to scope of the present invention.As a specific examples, multi-user unit 104 can be linked to base station 118, and perhaps low activity communicator 200 can be mutually integrated with subscriber unit 104.
Work
After receiving the TDD signal, vocoder that notice is used by system 100 during signal processing or detection have received low activity signal and can use 1/8th speed traffic channel frame formats to transmit for emission.Yet following method is adapted to 1/4th and can realizes to the full rate traffic channel, as discussed below.
Fig. 3 illustrates the typical non-variable rate vocoder frames form of the traffic channel that utilizes speed group 1.Rate changeable vocoder utilizes code to excite linear prediction (CELP) technology to produce a frame for per 20 milliseconds, and this technology is well-known in the art.Can be with frame formatting full rate, 1/4th or 1/8th rate format, this depends on voice activity.If receive the multi-tone of fighting, rate changeable vocoder will detect low activity usually and use 1/8th rate format, suppose that the standard vocoder in the current use can be transmitted by detection signal.Usually, many signals of fighting will be treated to noise and being left in the basket usually.
Full rate is meant that each position that is included in each frame is the unduplicated fact./ 2nd speed are meant that every frame transmits the frame of similar number, but repeat once each position in this frame, and promptly each idiotope will occur twice in this frame./ 4th speed are meant that each idiotope will occur four times in every frame, and the rest may be inferred.Transmit an information bit over and over again, the total information that every frame transmits is less.Under full rate, signal transmits with higher power, because one is only transmitted once for the location.Concerning the application, this full rate power level is called reference power.Because the power level that reduces is adopted to repeat than low rate in the position, because the power of the position of each repetition is accumulated on this frame.Suppose to adopt fixing minimum power to launch, the full rate emission will comprise than 1/2nd speed of identical information launches more frame error.
Typically, for transmitting of go up receiving at remote location (being also referred to as the target that transmits, as subscriber unit), power level is based on that selected FER (Floating Error Rate) (FER) sets.Required FER selects, because transmitting when hanging down activity signal, utilizes the actual FER of current method to increase.This selected FER scope still if desired can be greater or lesser between 0.1% and 1.0% error rate, with the quality that keeps transmitting.Preferably, for low activity signal, 0.2% FER is desirable.
In the present invention, implement special coding and decoding technology may command FER (Floating Error Rate).Even in the technology that discloses does not reach the situation of selected FER-the reconstruct of vocoder frame information after FER be restricted in this situation of total number of error frame-method of adjusting transmitted power level also can use with special coding and decoding technology.Typically, vocoder will be locked under the full rate, and transmitting power will increase to launch low activity signal.Should realize, if required any increase is still less than not implementing the required increase of this coding/decoding technology.
A. utilize the decoder of soft position
In one embodiment, when receiving TDD and call out, system 100 or notified or detect this type of call.System 100 utilizes standard process techniques well known in the art to handle calling from TDD unit 200 with emission.When in remote spots, for example during 118 received frames of base station, utilize the present invention to calling out decoding.If frame error has taken place in physical layer, if promptly this frame not by as the verification in IS-95, described and, still this frame is passed to vocoder 120 and decodes.The frame of mistake passed to vocoder is current in standard I S-95 implements not to carry out.The position that is included in the error frame is called " soft position ", because they can not be mistakes entirely, can be individually from they acquisition of informations, and be included in information in the error frame with reconstruct.
Yet, detect or notifiedly received the TDD calling, the vocoder decoder among the present invention by watching reception attentively the vocoder parameter and " signature " of these parameters contrasts TDD modulation signal or the tone of seeing in the vocoder parameter space handled error frame.The vocoder parameter of the sound sign indicating number coding TDD tone that this will store and the parameter of reception are made comparisons.This relatively causes which TDD most probable is received makes decision.
For example, suppose that the vocoder of the multi-tone of fighting of " 0 " represents to be represented as 16 " 0 " sequences, the expression of the multi-tone of fighting of " 1 " is expressed 16 " 1 ".This method considers that these are speech-parameter-spatial signatures.For following example, 3 layers are identified as: the vocoder frame border |-voc frame ' N '-| Baudot tone border |-Baudot ' N '-| and the vocoder parameter 000000000000000 that receives or
11111111111111111
Suppose that the vocoder decoder receives following parameter:
{ mismatch frame } |-voc frame 1-|-voc frame 2-|-voc frame 3-|-voc frame 4-|-voct ' 1 '-|-Baudot ' 0 '-|-Baudot ' 0 '-|-Baudot ' 1 '-|-| Baudot ' 0 '-| 11,111,111,000,000,000,000,000,000,000,000,000,001,100,001,111,111,111,100 00000000000000
^
[frame error]
The reception parameter that decoder identification is fought the multi-tone border and discerned second fight many " 0 " is more near " 0 " but not " 1 ".Fight multi-tone " 0 " and before decoding, revise the incorrect bit of suspecting of decoder decision.For the next one multi-tone " 1 " of fighting, decoder identification vocoder parameter is more near " 1 " but not " 0 ", and correspondingly revises the position.Decoder adopts following sequence to produce the TDD signal of correction now:
{ correct frames } |-voc frame 1-|-voc 2-|-voc frame 3-|-voc frame 4-|-voct ' 1 '-|-Baudot ' 0 '-|-Baudot ' 0 '-|-Baudot ' 1 '-|-Baudot ' 0 '-| 11,111,111,000,000,000,000,000,000,000,000,000,000,001,111,111,111,111,111 0000000000000000
This example shows that the mistake transition occurs on the frame boundaries, and situation is not always like this.If these transition drop in the frame usually, can be according to following employing another kind of form of the present invention.
If the vocoder decoder receives an error frame, in this frame, comprise incorrect bit here, vocoder can be watched the frame of adjacent zero defect or " good " attentively, with the reconstruct error frame.Consecutive frame will be included in a part of losing in the error frame multi-tone of fighting.For example, suppose to have received following signal:
{ mismatch frame } |-voc frame 1-|-voc frame 2-|-voc frame 3-|-voc frame 4-|-voct ' 1 '-|-Baudot ' 0 '-|-Baudot ' 0 '-|-Baudot ' 1 '-|-Baudot ' 0 '-| 11,111,111,000,000,000,011,111,111,111,100,000,000,011,111,111,111,111,100 00000000000000
^^
[frame error]
Second the fight vocoder parameter of multi-tone " 0 " is too uncertain so that can not make the accurate decision of tone because in the vocoder frame parameter number of " 0 " almost the number with " 1 " is identical.In order to make better decision, vocoder is watched next consecutive frame (voc frame 3) attentively and is determined this tone to occur to proceed in this frame as " 0 ".Therefore the decoder decision this means that be many " 0 " tone of fighting at the back of vocoder frame 2 in half.
As shown in the flow chart of Fig. 4, after having determined to receive low activity signal in task 402 and 404, decoder continues to monitor and upgrade the multi-tone border of fighting that receives in task 408.Otherwise, utilize any low activity signal of conventional process.If as the reception that in physical layer, detects error frame, distribute a designator N in task 410, for this frame, vocoder is checked this error frame.If whether can make about this frame is " reliably " decision of many " 0 " or " 1 " of fighting, revise the parameter of this error frame so with the reflection decision.Reliable decision is the decision that drops in the regulation probability that obtains the primitive frame parameter.For the purpose of the present invention, required probability is then in 51% deterministic scope.If modify, method turns back to task 402, and definite next signal.
If shown in task 412, can not make reliable decision, vocoder is commented next consecutive frame N+1, or N-1.In task 416, if this frame is good, the parameter based on comprising in frame N+1 or the frame N-1 modifies the decision of error frame in task 418.If two next consecutive frames are not good, so based on the parameter that is included among next adjacent N+1, make next best decision reliably, correspondingly revise the parameter of frame N.
B. utilize the encoder of soft position
Decoder implementation of class in this embodiment of the invention is similar to discussed above.Yet in order further to reduce error rate and accuracy and the reliability of improving decoded signal, encoder also has the advantage of " soft position ".
When the vocoder coding device detected the multi-tone of fighting and will transmit, decoder switched to " multi-tone of fighting coding mode ".In this pattern, the encoder decision is " 0 " or " 1 " for the tone that receives as coding.Then, encoder utilizes vocoder frame that this decision is sent to decoder, but utilizes code redundancy to improve the decoder chance of determining the suitable multi-tone of fighting.Even decoder receives the tone in the error frame, it will have the more maximum-likelihood of the correct tone of the transmission of obtaining owing to the decision of sending.
Simplify in the example at one, will launch if encoder detects fight many " 1 ", it is sent to decoder with a series of 1.This series can be any length, but must be enough to if desired to make decoder can resemble above in joint A, discuss work.Therefore this form of the present invention makes it be easier to make decision between two tones, even when frame is mistake with vocoder " signature " the alternate standard vocoder parameter of better space spaced apart (being easier to distinguish).
C. do not utilize the encoder of soft position
This embodiment of the invention is the another kind of form of the method described in joint A and B, but does not give decoder soft position from any mistake vocoder frame to be processed.
In this case, when multi-tone was fought in vocoder coding device detection " 1 " or " 0 ", vocoder utilized redundancy also to vocoder frame medium pitch coding, but coding carries out on many vocoder frames." 1 " and " 0 " if by between be inserted in that some frame M go up so that a LOF, decoder can extract necessary information from consecutive frame.Following example is illustrated in interleaving of taking place on the frame, but can adopt the frame of any number.Suppose to fight below the encoder detection multi-tone for launching:
11001
Encoder is encoded to frame according to following, for being transmitted into decoder: |-voc frame 1-|-voc frame 2-|-voc frame 3-|-voc frame 4-|-voc frame 5|-Baudot ' 1 '-|-Baudot ' 1 '-|-Baudot ' 0 '-|-Baudot ' 0 '-|-Baudot ' 1 '-xxxxxxxxxxxx1111xxxxxxxx11111111xxxx11111111000011111111 000000001111000000001111
In this example, the vocoder frame parameter of each frame is by segmentation, and the detected multi-tone of fighting in the specific vocoder frame is represented in 4 positions here.The detected multi-tone of fighting from last 4 vocoder frames is represented in whole 16 positions:
| fighting of frame N-3 is many | and fighting of frame N-2 is many | and fighting of frame N-1 is many | and frame N fights many |
In order to take into account the multi-tone of fighting that does not correspond to the vocoder frame border, the present invention adopts 4 following bit sequences, and XXYY indicates the code in the current vocoder frame to reflect that the Baudot code of " X " is the Baudot code of " Y " subsequently here: |-voc frame 1-|-voc frame 2-|-voc frame 3-|-voc frame 4-|-voct ' 0 '-|-Baudot ' 1 '-|-Baudot ' 1 '-|-Baudot ' 0 '-|-Baudot ' 0 '-| xxxxxxxxxxxxx0011xxxxxxxx00111111xxxx0011111111000011111 1110000001111
D. has the improvement vocoder that increases transmitting power
In another embodiment, revising mobile radio station chips group is advantageously to reduce to minimum with the cost forbidden of realizing the above Code And Decode process of discussing in joint A, B and C.
The Code And Decode method of joint A, B and C can be connected and communicate by letter and advantageously realization by using standard vocoder and single booster (maybe can carry out any other device of single enhancement function as estimator or transponder).In addition, the method for joint A, B and C can be by using improved Realization of Vocoder.For the professional and technical personnel of this area, obviously can improve the function of vocoder, make promptly whether the corrupt bits that is received by communication unit is the estimation of conduct " 0 " or " 1 " original transmitted with the single booster of further adding.
The system of Fig. 5 illustrates one embodiment of the present of invention.550 transmissions to mobile radio station 510 are called forward link from the base station, and 550 transmission is called reverse link to the base station from mobile radio station 510.In reverse link, the many signal encodings of will fighting of the not improvement vocoder 520 in the mobile radio station 510 are standard vocoder parameter and this vocoder parameter is transmitted into base station 550.Improved vocoder 560 receives the many signals and strengthen this many signals of fighting to recover the position of error of fighting of these codings.Produce the form of knowing of many signals of fighting then.In forward link, the not improved vocoder 580 in the base station 550 utilizes the standard vocoder parameter to fighting many signal encodings and the vocoder parameter is transmitted into mobile radio station 510.Improved vocoder 530 receives the many signals and strengthen this many signals of fighting to recover the position of error of fighting of these codings.Produce the form of knowing of signal then.
Yet the coding/decoding method that utilizes Signal Booster or improved vocoder to be implemented on the two to discuss among joint A, B and the C at forward link and reverse link can be very expensive and forbid producing.In another embodiment of the present invention, by utilizing the single booster in the base station on the reverse link and by utilizing power control techniques to regulate the FER (Floating Error Rate) that the signal transmission power level from the base station to the mobile radio station on the forward link can reduce system.
In the reverse link of the communication system of Fig. 6, base station 655 is included in original many signals of fighting in the vocoder coding frame according to the method reconstruct of discussing among joint A, B and the C.Yet, in forward link, it is 09/114 that base station 655 utilizes at application number, 344 exercise question is many signals of fighting of the power control techniques launching code discussed in the U.S. Patent application of " setting up the method and apparatus of TDD/TTY business on sound sign indicating number encoding channel ", this application has transferred assignee of the present invention, introduces by reference at this.
Fig. 7 is the flow chart of the method for transmitting power between control base station and the mobile radio station.Method is from task 702, and many signals of fighting here are moved station 605 and receive.After signal was received, in task 704, the vocoder that is used by mobile radio station 605 during the Signal Processing process was locked into full rate.In the present embodiment, in task 710, transmitting power is not that full rate is launched employed transmitting power reduction from telecommunication system.For transmitting of receiving at mobile radio station 605 places, power level is set based on selected FER usually.Required FER selects, because when many signals of fighting are being transmitted, the actual characters error rate of many signals of fighting is about 9 to 10 times of FER.This selected FER scope still if desired can be littler between 0.1% and 1.0% error rate, with the quality that keeps transmitting.Preferably, for emission many signals of fighting, 0.2% FER is desirable.In task 712, if FER surpasses selected scope, mobile radio station 605 needs system to regulate to reduce FER with customary way informing base station 655 during task 706.So, in task 708, make adjusting.Adjusting generally includes the transmitting power that increases the full rate emission, but also can comprise other parameters that adjusting is known, to reduce FER.If FER is an acceptable in task 712, signal emission can continue in task 714, and the dynamic adjustments of telecommunication system is continued in the emission 710 of entire transmit signal.Otherwise when the emission of many signals of fighting finished, vocoder was nonlocking, and telecommunication system returns normal running.
Other embodiment
Though what shown present consideration is preferred embodiment of the present invention, for the professional of this area, obviously can make various changes and modifications, and the scope of the present invention that limits without prejudice to appending claims.
Claims (17)
1. method that is used for transmitting the notified low activity signal of communication of telecommunication system, described telecommunication system comprises mobile radio station and base station, it is characterized in that described method comprises:
Emission is by the primitive frame of original bit sequence representative;
Receive first frame emission, described first frame emission comprises the first emission bit sequence, and the described first emission bit sequence is substantially the same in ordering with original bit sequence;
Strengthen the first emission bit sequence to produce the bit sequence that strengthens; And
Handling the bit sequence that strengthens is the employed additional information of original bit sequence in the identification primitive frame with the acquisition.
2. the method for claim 1 is characterized in that: the step of handling the bit sequence that strengthens further comprises:
The bit sequence of enhancing and known low activity signal of communication bit sequence are compared;
Determine whether the bit sequence that strengthens statistically is reliable; And
If the bit sequence that strengthens statistically is reliably, revise this enhancing bit sequence so with the original bit sequence in the identification primitive frame.
3. the method for claim 1, it is characterized in that: the bit sequence of enhancing is labeled frame N, and the step of handling the bit sequence that strengthens further comprises:
The bit sequence of enhancing and known low activity signal of communication bit sequence are compared, to produce comparative result;
If comparative result is indicated reliability of statistics, revise the bit sequence of this enhancing so based on this comparative result, to reflect known low activity signal of communication bit sequence;
If but comparative result is not to add up reliably, handles the frame N+1 of adjacent frames N so, to determine whether frame N+1 comprises any mistake;
If frame N+1 is a zero defect, determine the low activity communication that limits by the bit sequence that is included among the frame N+1 so; And
Based on the enhancing bit sequence that is included in the bit sequence modification frame N among the frame N+1.
4. method as claimed in claim 3 is characterized in that: if known low activity communication bit sequence will reflect that the probability of original bit sequence is 51% or bigger, described comparative result indication reliability of statistics.
5. the method for claim 1 is characterized in that: the step of emission primitive frame is undertaken by mobile radio station, and the step that receives first frame emission is undertaken by the base station.
6. the method for claim 1, it is characterized in that: described method further comprises with the alternative step by the employed standard vocoder coding/decoding of a plurality of vocoders parameter of vocoder signature, wherein be included in the vocoder signature the serializing position than on the further space, serializing position that is included in the standard vocoder parameter separately, described alternative steps is prior to step of transmitting.
7. method as claimed in claim 6 is characterized in that: the step of alternate standard vocoder parameter further comprises:
Low activity signal of communication is being launched in transmission to first vocoder; And
With second vocoder this low activity signal of communication is encoded, second vocoder determines that a position is 0 or 1, utilize the interior channel code redundancy of information bit field of primitive frame to encode, to improve the likelihood to first vocoder of primitive frame decoding, coding also notifies the low activity signal of first vocoder to be launched.
8. method as claimed in claim 6 is characterized in that: the step of handling the bit sequence that strengthens further may further comprise the steps:
The bit sequence of enhancing and known low activity signal of communication bit sequence are compared; And
Situation is revised the bit sequence that strengthens based on the comparison, with the identification original bit sequence.
9. method that is used for transmitting the notified low activity signal of communication of telecommunication system, described telecommunication system comprises mobile radio station and base station, it is characterized in that described method comprises:
Launch first primitive frame from mobile radio station, wherein first primitive frame is represented by first original bit sequence;
Receive first frame emission in the base station, described first frame emission comprises the first emission bit sequence, and the described first emission bit sequence is substantially the same in ordering with first original bit sequence;
Strengthen the first emission bit sequence in the base station, to produce the bit sequence that strengthens;
The bit sequence of this enhancing is delivered to first vocoder in the base station;
Handling the bit sequence of this enhancing with first vocoder, is the employed additional information of first original bit sequence in identification first primitive frame with the acquisition; And
With the transmitted power level that increases from base station second primitive frame.
10. method as claimed in claim 9 is characterized in that: further may further comprise the steps with the transmitted power level that the increases step from base station second primitive frame:
To handle that employed all vocoders lock onto full rate in second primitive frame; And
Launch second original bit sequence with the transmitted power level that increases, to keep the minimum target FER (Floating Error Rate) of second original bit sequence.
11. method as claimed in claim 9 is characterized in that: the bit sequence of enhancing is labeled frame N, and the step of handling the bit sequence that strengthens further comprises:
The bit sequence of enhancing and known low activity signal of communication bit sequence are compared, to produce comparative result; With
If comparative result is indicated reliability of statistics, revise the bit sequence of this enhancing so based on this comparative result, to reflect known low activity signal of communication bit sequence;
If but comparative result is not to add up reliably, handles the frame N+1 of adjacent frames N so, to determine whether frame N+1 comprises any mistake;
If frame N+1 is a zero defect, determine that so low activity signal of communication is limited by the bit sequence that is included among the frame N+1; And
Based on the enhancing bit sequence that is included in the bit sequence modification frame N among the frame N+1.
12. method as claimed in claim 11 is characterized in that: if known low activity communication bit sequence will reflect that the probability of original bit sequence is 51% or bigger, described comparative result indication reliability of statistics.
13. method as claimed in claim 11 is characterized in that: further may further comprise the steps with the transmitted power level that increases step from base station second primitive frame:
To handle that employed all vocoders lock onto full rate in second primitive frame; And
Launch second original bit sequence with the transmitted power level that increases, to keep the minimum target FER (Floating Error Rate) of second original bit sequence.
14. method as claimed in claim 13 is characterized in that: the minimum target FER (Floating Error Rate) is less than 1.0%.
15. be used to transmit the device that hangs down the activity signal of communication in the telecommunication system, it is characterized in that described device comprises:
The primitive frame of low activity signal of communication is encoded to the device of original bit sequence;
Launch the device of this original bit sequence;
Receive the device of first frame emission, described first frame emission comprises the first emission bit sequence; And
Strengthen the first emission bit sequence is known signal with generation device with Signal Booster.
16. device as claimed in claim 15 is characterized in that: described device further comprises:
The device that the bit sequence of this enhancing and known low activity signal of communication bit sequence are compared;
Whether the bit sequence of determining this enhancing is statistics device reliably;
The device of the reliability of statistics of the bit sequence that verification should strengthen; And
Revise the device of the bit sequence of this enhancing with the original bit sequence in the identification primitive frame.
17. be used to transmit the device of notified low activity signal of communication in the telecommunication system, it is characterized in that described device comprises:
The primitive frame of low activity signal of communication is encoded to the vocoder of original bit sequence;
Launch the reflector of this original bit sequence;
Receive the receiver of first frame emission, described first frame emission comprises the first emission bit sequence; And
Strengthen the first emission bit sequence and know the Signal Booster of signal with generation.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US36671499A | 1999-08-04 | 1999-08-04 | |
| US09/366,714 | 1999-08-04 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1375146A true CN1375146A (en) | 2002-10-16 |
| CN1178438C CN1178438C (en) | 2004-12-01 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB008112487A Expired - Fee Related CN1178438C (en) | 1999-08-04 | 2000-08-03 | Method and apparatus supporting TDD/TTY modulation over vocoded channels |
Country Status (14)
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| EP (1) | EP1198934A1 (en) |
| JP (1) | JP2003506968A (en) |
| KR (1) | KR20020037342A (en) |
| CN (1) | CN1178438C (en) |
| AU (1) | AU773419B2 (en) |
| BR (1) | BR0012932A (en) |
| CA (1) | CA2379973A1 (en) |
| HK (1) | HK1047836B (en) |
| IL (1) | IL147717A0 (en) |
| MX (1) | MXPA02001199A (en) |
| NO (1) | NO20020517D0 (en) |
| RU (1) | RU2002105522A (en) |
| UA (1) | UA70375C2 (en) |
| WO (1) | WO2001011840A1 (en) |
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| BR0313259A (en) | 2002-08-06 | 2005-06-14 | Siemens Ag | Error handling of useful information received through a communication network |
| US9226123B2 (en) * | 2013-02-21 | 2015-12-29 | Telefonaktiebolaget L M Ericsson (Publ) | Limiting processing of calls as text telephony calls |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ATE194900T1 (en) * | 1992-05-20 | 2000-08-15 | Ultratec Inc | TELECOMMUNICATIONS DEVICE WITH IMPROVED TDD (TELECOMMUNICATIONS DEVICE FOR THE HARD OF HEARING) PROTOCOL |
| FI100932B (en) * | 1995-04-12 | 1998-03-13 | Nokia Telecommunications Oy | Transmission of audio frequency signals in a radiotelephone system |
| WO1998027758A2 (en) * | 1996-12-19 | 1998-06-25 | Diva Communications | Methods and apparatus of providing transparency of dtmf signaling tones across a digital cellular voice channel |
| US6434198B1 (en) * | 1998-08-28 | 2002-08-13 | Lucent Technologies Inc. | Method for conveying TTY signals over wireless communication systems |
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2000
- 2000-03-08 UA UA2002010288A patent/UA70375C2/en unknown
- 2000-08-03 BR BR0012932-1A patent/BR0012932A/en not_active IP Right Cessation
- 2000-08-03 AU AU65238/00A patent/AU773419B2/en not_active Ceased
- 2000-08-03 WO PCT/US2000/021441 patent/WO2001011840A1/en not_active Application Discontinuation
- 2000-08-03 IL IL14771700A patent/IL147717A0/en unknown
- 2000-08-03 EP EP00952564A patent/EP1198934A1/en not_active Withdrawn
- 2000-08-03 KR KR1020027001541A patent/KR20020037342A/en not_active Application Discontinuation
- 2000-08-03 CA CA002379973A patent/CA2379973A1/en not_active Abandoned
- 2000-08-03 JP JP2001515594A patent/JP2003506968A/en active Pending
- 2000-08-03 MX MXPA02001199A patent/MXPA02001199A/en unknown
- 2000-08-03 RU RU2002105522/09A patent/RU2002105522A/en not_active Application Discontinuation
- 2000-08-03 CN CNB008112487A patent/CN1178438C/en not_active Expired - Fee Related
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2002
- 2002-02-01 NO NO20020517A patent/NO20020517D0/en not_active Application Discontinuation
- 2002-12-30 HK HK02109400.3A patent/HK1047836B/en not_active IP Right Cessation
Also Published As
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|---|---|
| RU2002105522A (en) | 2003-09-10 |
| AU773419B2 (en) | 2004-05-27 |
| AU6523800A (en) | 2001-03-05 |
| IL147717A0 (en) | 2002-08-14 |
| WO2001011840A1 (en) | 2001-02-15 |
| EP1198934A1 (en) | 2002-04-24 |
| BR0012932A (en) | 2003-04-29 |
| CA2379973A1 (en) | 2001-02-15 |
| NO20020517L (en) | 2002-02-01 |
| JP2003506968A (en) | 2003-02-18 |
| MXPA02001199A (en) | 2002-07-30 |
| NO20020517D0 (en) | 2002-02-01 |
| UA70375C2 (en) | 2004-10-15 |
| CN1178438C (en) | 2004-12-01 |
| HK1047836A1 (en) | 2003-03-07 |
| HK1047836B (en) | 2005-07-22 |
| KR20020037342A (en) | 2002-05-18 |
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