CN1313017A - System for elimination of audible effects of handover - Google Patents
System for elimination of audible effects of handover Download PDFInfo
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- CN1313017A CN1313017A CN99809482A CN99809482A CN1313017A CN 1313017 A CN1313017 A CN 1313017A CN 99809482 A CN99809482 A CN 99809482A CN 99809482 A CN99809482 A CN 99809482A CN 1313017 A CN1313017 A CN 1313017A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/02—Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/08—Reselecting an access point
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/24—Reselection being triggered by specific parameters
- H04W36/30—Reselection being triggered by specific parameters by measured or perceived connection quality data
- H04W36/302—Reselection being triggered by specific parameters by measured or perceived connection quality data due to low signal strength
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W24/00—Supervisory, monitoring or testing arrangements
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W28/00—Network traffic management; Network resource management
- H04W28/02—Traffic management, e.g. flow control or congestion control
- H04W28/06—Optimizing the usage of the radio link, e.g. header compression, information sizing, discarding information
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W76/00—Connection management
- H04W76/20—Manipulation of established connections
- H04W76/28—Discontinuous transmission [DTX]; Discontinuous reception [DRX]
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Abstract
Audible effects of handover of a mobile subscriber station (M1, 22) in a digital cellular system are eliminated in either the uplink (UL) or the downlink (DL) by implementing discontinuous transmission (DTX) within the system on either or both of the links. A voice activity detector (VAD) monitors whether speech or non-transparent data is originating from a party and, if not, the transmission of that party is interrupted and only a single SID frame is sent during each SACCH period to update the background noise characteristics being generated at the other parties' receiver. Once it is determined by the system that a handover of a mobile needs to be performed (32), that handover is delayed until the party on the link on which DTX is implemented is neither talking nor sending non-transparent data (34) ensuring that the other party is having comfort noise being generated in its receiver and, thus, will not hear any audible effect of the handover.
Description
The background of invention
FIELD OF THE INVENTION
The present invention relates to cellular radio telecommunication system, and relate more specifically to be used to eliminate method and system the audible effects of cellular radio user terminal when a sub-district switches to another sub-district.
Description of Related Art
In cellular radio telecommunication system, wherein a plurality of mobile radio stations thus system the area dividing of service is provided is the sub-district.In the sub-district mobile radio station of each idle and work with keep wireless contact for that sub-district serving base station.In routine operation, when the mobile radio station that carries out efficient communication when a sub-district moves to another sub-district, this cellular system is carried out handover (switching), in this handover procedure, the mobile radio station that indication is being moved retunes to new Traffic Channel by the base station services of its sub-district that enters subsequently with its wireless device.The main cause of carry out switching be the mobile radio station experience its Serving cell signal quality deterioration and the existence from the signal of base station of neighbor cell of better signal quality can be provided for it.
Cellular system must be known the approximate location of each mobile radio station that carries out efficient communication for effective handover and service management function are provided.Generally provide positional information by the signal strength signal intensity of wireless signal of measuring the wireless signal that between this mobile radio station and its serving BS, transmits and serving the adjacent base station of the sub-district in the geographic area on every side.
The basic norm that the good wireless air interface connects between portable terminal and the base station in the definition cellular system is: have carrier signal strength above the preselected threshold value, have and utilize the defined relative high speech quality in described connection of Carrier interference ratio (C/I); And the exploitable channel that in Serving cell, has sufficient amount.As long as any one criterion among these criterions is no longer satisfied in the user terminal base station of communicating by letter with it, this system just attempts this connection is switched in this system more suitably sub-district.Because making great efforts to increase its network capacity, system operator comes to provide service for the mobile subscriber who accelerates day by day, so the geographic size of sub-district is constantly reducing in this system, this will make system operator can increase the capacity of this system by the utilized frequency channels of multiplexing limited quantity more continually.Because the result of sub-district reduced size, the increase of this channeling also makes each calling will have more switching times.
Send necessary signaling by the old Traffic Channel in the current service cell between portable terminal and cellular network and carry out the switching of mobile radio terminal from a sub-district to another sub-district, the new Traffic Channel that belongs to Target cell is directly transferred in the wireless connections of this calling after this.This certainly leads to the voice interruption of the weak point that generally has the hundreds of millisecond order of magnitude during Traffic Channel is from a sub-district to the actual transfer of another sub-district.The both sides of conversation can hear that such Traffic Channel interrupts, and such interruption during the individual call when continuous a plurality of switchings occur troublesome very.
System of the present invention provides a solution to the audible effects problem of switching, and it can eliminate the voice interruption that conversation one side or both sides can perceive in most applications.
Brief summary of the invention
One aspect of the present invention relates to the audible effects that minimizing is switched at least one link in the Traffic Channel of the wireless air interface of cellular wireless system.Implementing discontinuous transmission (DTX) in link, is to constitute the audible effects that reduces switching by voice, non-transparent data or background noise by each traffic frame of detecting in this link in this link.Send quiet descriptor (SID) frame that comprises the relevant information of background noise in the link therewith and give receiver from transmitter, detecting with response does not both have voice not have non-transparent data to appear in this link yet.Incoming traffic frame in the warning receiver and when detecting the SID frame in this receiver upgrades comfortable noise characteristic and generate comfortable noise in this receiver.When the switching of determining to carry out mobile radio station on this link when responding this intrasystem signal measurement, then postpone execution, until the SID frame that on this receiver, receives preselected number continuously to that switching.The side that this expression is in emission is not but receiving comfortable noise generating voice or non-transparent data and receiver.For responding this condition, carry out the switching of mobile radio station from a BTS to another BTS, this can eliminate the audible effects of recipient's switching, because will generate comfortable noise in whole handoff procedure.
In another aspect of this invention, the audible effects that reduce to switch in the digital cellular wireless system is wherein being implemented discontinuous transmission (DTX) at least one channel among the up link of this system or the downlink radio channel.The DTX interruption comes My World on link wireless transmission, described this side does not send the communication information constantly at that, indicates to the opposing party but the transmission expression should generate the periodicity of the rule of comfortable noise in the opposing party's receiver.Mobile radio station the needs from a sub-district to the switching of another sub-district of surveillance execution as a side of described communication are gone back in the transmission that the periodicity that supervision is sent by a side who does not constantly send the communication information at that is indicated simultaneously.Postpone the execution of required switching, come comfortable that not send a side's of the communication information the periodicity indication of rule of preselected number constantly until receiving, receive only comfortable noise and thereby the audible effects of switching that not uppick is being carried out constantly at that to guarantee the opposing party.In case this condition exists, and just carries out required switching.
In order to understand the present invention and other purpose and advantage thereof, now can be referring to description, wherein below in conjunction with accompanying drawing:
Fig. 1 can be used for comprising of embodiments of the invention of a plurality of sub-districts and the schematic diagram of the cellular wireless system of base station;
Fig. 2 is that represent wherein can be in conjunction with the functional-block diagram of the cellular communication system of the employing sectorized antennas of one embodiment of the invention;
Fig. 3 is the schematic diagram of carrying out signal strength measurement in the cellular wireless system and mobile subscriber terminal being switched to the mode of another sub-district from a sub-district;
Fig. 4 is the flow chart of some aspect of the algorithm that uses in the system of the present invention of expression;
Fig. 5 is that the timing diagram that can listen transition effects is eliminated in expression according to one aspect of the invention;
Fig. 6 represents to eliminate according to a further aspect of the invention the timing diagram that can listen transition effects; With
Fig. 7 is that the timing diagram that can listen transition effects is also eliminated in expression on the one hand according to the present invention;
For the environment that wherein can propose detail of the present invention is provided, will total structure of cellular mobile radio system and operation be described at first.
Fig. 1 is the figure that expression comprises such system of 10 sub-district C1-C10.Certainly, cellular wireless system comprises the sub-district more than 10, but explanation for this reason can think that the system shown in Fig. 1 is an independent sector of big system, only illustrates wherein 10 sub-districts.
In each sub-district C1-C10, has a corresponding base station B1-B10 who serves that sub-district.In the example embodiment of Fig. 1, base station B1-B10 is expressed as near the central authorities that have omnidirectional antenna and be positioned at the sub-district, yet, those skilled in the art will recognize that other zones that these base stations generally can be positioned at the sub-district (for example, be positioned at the intersection of three neighbor cells) and have sectorized antennas, so that single base station can be served three sub-districts.A plurality of mobile radio station M1-M10 also shown in Figure 1, these mobile radio stations can move in each sub-district and move to another sub-district from a sub-district.Certainly, a typical cellular system has more than 10 mobile radio station and works in this system.Moving exchanging center MSC 1 utilizes cable or microwave to be connected to each base station B1-B10 and is connected to switched message network (PSTN).
Distribute a special frequency band for each cellular radio telecommunication system, this system must operate in this frequency band.This frequency band is subdivided into the unit that is called frequency, the combination of these frequencies is distributed to the sub-district that is arranged in the specific region.Because limited wireless frequency spectrum, so when the business that the demand of Traffic Channel quantity increases in owing to system in each sub-district increases, system operator is tending towards its system of reconstruct constantly, generally by reducing geographic range that each sub-district covers to increase this intrasystem channeling.The reducing of this cell size means when mobile radio station is special during each is called out during in moving between cells in whole system to have a switching of accelerating.
Fig. 2 represents to adopt another example cellular radio telecommunication system of the base station that all has three sectorized antennas.These systems with 10 expressions comprise cellular network 12 generally, and this network comprises and is positioned at the spaced apart locational a plurality of fixed base stations 16 of whole geographic area hollow.In the signal of Fig. 2, sub-district 18 of 16 definition, each base station, and the group of three base stations 16 is positioned at together, and also each is positioned at together base station services in adjacent but sub-district 18-18 the overlay area independently of three of definition.Each base station 16 generally comprise the stationary transceivers of the sectorized antennas that use to cover approximate 120 ℃ and be positioned at its service the sub-district around.When mobile radio station was positioned at the communication zone of one of base station, each base station 16 allowed and is positioned at mobile subscriber terminal at a distance (such as, user terminal 22) and carries out radio communication.
Utilize the sub-district 18-18 of the overlay area definition of base station to be expressed as pure hexagon shape for explanation.In the system of reality, the communication range of base station (that is overlay area) is the difference shown in the figure therewith.That is to say that sub-district 18-18 also may be asymmetric with respect to the base station, and might be different mutually in shape by the sub-district 18-18 of different base station 16-16 definition.In the cellular radio Communication system of reality, the overlay area (such as, adjacent base station) also to a certain degree overlapped.
The group of base station 16-16 is coupled to base station controller (BSC) 24.Communication line 26 is coupled to BSC24 with base station 16-16, and BSC24 utilizes communication line 28 to be coupled to mobile switching centre (MSC) again, such as MSC27.
As shown in Figure 2, when mobile subscriber terminal 22 is communicated by letter with another mobile communication station that is connected to this network, can utilize base station 16 these communications of control in the network 12.When portable terminal 22 was mobile between the 18-18 of the sub-district of network 12, ongoing communication was switched between adjacent base station 16-16.If this portable terminal is in the idle pulley, when this mobile radio station is carried out such as the cell selecting during occurring in registration procedure during in moving between cells.
Referring to Fig. 3, the periodic measurement that its wireless air interface is connected obtain the quality criterion that is undertaken by its Serving cell and its neighbor cell with the mobile radio station 22 of first base station communication of serving sub-district A is shown.In case definite one or more quality criterions have dropped to and have been lower than the preliminary election minimum value, this network then makes wireless air interface transfer to the base station of just serving the mobile radio station in the B of sub-district from sub-district A.Wireless connections be transferred to from sub-district A sub-district B during, in Traffic Channel, have of short duration interruption, that this normally can hear for a side of conversation or both sides and the people is upset and worried.
Proposed that many different prior aries attempt solving the problem of long voice interruption time.Wherein a kind of technology adopts different programs to reduce switching times as far as possible or eliminates the effect of these switchings and can listen influence.
Employed a kind of method is: in the process of switching in a BSC, code converter and rate adaptor (TRA) are connected to BTS and finish conversion in this TRA.This causes the remarkable improvement of the effects visible switched on the up link, wherein interrupts reducing to about 20-40 millisecond.The another kind of method representation of eliminating transition effects is in the U.S. Patent number 5640679 of authorizing people such as Lundqvist, wherein measured the time migration of mobile radio station between Serving cell and Target cell, and subsequently this time deviant is sent to this mobile radio station, so that this mobile radio station can move it regularly and more approaching synchronously with Target cell between transfer period, thereby eliminate usually for required circuit interruption time synchronously again.It is said that this technology allows to utilize Voice decoder to shelter to interrupt and interruption is restricted to less than 40 milliseconds.
Also a kind of method of head it off is: be not noise elimination to quietness but noise elimination to comfortable noise level so that reduce audible effects on the up link.Noise elimination makes it near comfortable noise level to use a kind of improved algorithm to come gradually, is inaudible thereby make switching for the listener.In addition, thus SID upgrades interpolation can be provided in each continuous SID and upgrade the mild conversion of continuous trend between frame and improve silent period during the subjective quality of comfortable noise on the receiving terminal.
From the viewpoint of voice quality, a subject matter in the switching is the voice interruption time, and to make the importance of voice interruption time minimization between transfer period in intensive frequency reuse networks be significant.Yet these above-mentioned prior aries are not all eliminated the voice deterioration that perceives between transfer period fully and are just reduced tangible voice interruption time and tangible effect thereof.
Method and system of the present invention adopts the technology of having been implemented and be called as discontinuous transmission (DTX) by many cellular radios.The TDMA cellular wireless system special benefit of the U.S. PC1900 tdma system that provides such as global system for mobile communications (GSM) or Ericsson wireless system company that adopts frequency hopping is in the interpolation of this DTX.The DTX function for example is defined and is described among the GSM standard GSM 06.31 and in European Telecommunication Standard ETS300 580-5 and embodies, and these two is introduced in this as a reference especially.Usually, the DTX function generally is quiet opinion on about 50% time based on each participant during conversing.If do not say any words, then utilize wireless transmission to send any content in the air, thereby just carry out wireless transmission when only on connecting, detecting voice to just nonsensical facing to the microphone of mobile radio terminal.This DTX program reduces the power consumption in mobile subscriber terminal (MS) and the base-station transceiver system (BTS) and also reduces and is transmitted into aerial wireless power.Because the power level of using when influence reality sends, so the C/I ratio of all connections raises when implementing DTX.DTX is used to reduce MS and BTS power consumption and reduces this intrasystem interference and only be used for the transmission of Traffic Channel (TCH) frame.DTX can be used for up link (UL) Traffic Channel (from mobile radio station to the base station) or down link (UL) Traffic Channel (from the base station to mobile radio station) individually or be used for both simultaneously.
The major part of DTX function comprises the speech activity detector (VAD) in BTS and/or the MS transmitter.The general utility functions of VAD and operational example are used as defining and being described among global system for mobile communications (GSM) the standard GSM 06.32 and in etsi standard ETS300 580-6, and these two is introduced in this as a reference especially.
In a word, can to detect traffic frame be to constitute by voice, non-transparent data or by background noise to the VAD in BTS or the MS transmitter.If this frame only is made of noise, then transmitter sends a quiet descriptor frame (SID), and stops transmission subsequently.Follow after initial SID frame, during each SACCH cycle, send a new SID frame, until in traffic frame, detecting speech or non-transparent data again.As usually, on SACCH, send signal quality measured report.Each SID frame comprises the information of the background noise of the connection of having set up that is monitoring about this VAD.
In the receiver of MS that the DTX function operates just therein or BTS, the SID frame detector is checked all incoming frames.This SID frame detector can be distinguished SID frame and voice or non-transparent data frame, and when detecting the SID frame, upgrades the comfortable noise characteristic in this receiver, and generates comfortable noise according to these characteristics.When detecting speech frame, interrupt comfortable noise and generate, and be listener's this voice of decoding.Thereby, mainly due to following two former thereby between transmitter and receiver, sending the SID frame during the silent period: (1) is in order to upgrade the comfortable noise characteristic on the receiver side; (2) in order to carry out and strength of transmitted signals and signal quality measured.VAD must operate always, to determine whether input signal comprises voice or non-transparent data.The per 480 milliseconds of transmission information in measurement report just of mobile radio station and/or BTS are to show in that interim whether use DTX sometimes.
In most of contemporary networks, be usually used in saving the battery consumption of mobile radio station during DTX in the up link (UL).Yet the DTX in the down link (DL) uses the saving of the caused voice deterioration of DTX function specific power more remarkable with the benefit that reduces the interference aspect because most of network operators perceive, thereby seldom uses.
Method and system of the present invention works in the mode what are different from several prior aries previously discussed.That is, technology of the present invention does not reduce break period of Traffic Channel but the effect of " hiding " or " sheltering " these interruptions, can listen sensation to remove the terminal use.System of the present invention comprises existing DTX function in above-mentioned cellular wireless system, and adopts this function by carrying out to switch during the silent period of conversation when only generating comfortable noise for the listener.Utilize the technology of the present invention, postpone this switching, until receiving several SID frames (the selectable frame number of network operator) continuously, the expression user listens attentively to another people's speech constantly rather than is just breathing between two sentences in conversation at that.When using the DTX function, during the whole SACCH cycle, only send a SID frame, thereby during not from the several successive SID frame of any voice of that user, in less than 200 milliseconds time, carry out rapidly and switch detecting that several SACCH cycle has been passed through in expression.By using this technology to come timing is carried out in switching, eliminate the audible effects of voice interruption for one of both sides of the communication that just in receiver, receives comfortable noise at that constantly.
And, during the dB of the high a certain quantity of switching between two sub-districts will occur in Target cell in the most applications signal intensity ratio current service cell.Usually in fact can postpone this switching and the specific wireless air interface of that mobile radio station or whole network is not caused any serious quality problems.Yet, in comprising the embodiment that can make the control of the function of advising of section sometime of this switching delay, also adopt the timer that can be chosen as a certain numerical value by the network operator.In the sort of situation, if system determine to have switched essential after, before the preselected time period expires, do not detect or detect the continuous SID frame of not enough quantity, in any case then will carry out not unexpected lose of switching to avoid connecting yet.
The algorithm that is used for the actual enforcement of carry out switching according to the technology of the present invention also preferably includes the supervision to the wireless air interface quality of this connection.If signal quality parameter (such as, signal strength signal intensity or bit error rate (BER)) drop to the changing down that is lower than a preset value or these parameters and surpass a preselected threshold value speed, then carry out and switch and no matter whether in the data that monitor relevant DTX parameter such as the SID cycle.Yet great majority switch under relative good signal quality and the signal strength condition and carry out, and in this case the delay of the 5-10 second before reality is switched to the not influence of this quality.
Next referring to Fig. 4, an exemplary enforcement algorithm is shown in a flowchart.31, this system begins and transfers to 32, determines whether to satisfy switching criterion 32.If unsatisfied words keep current wireless connections.Yet, if satisfied switching criterion 32, this system transfer to 33 and the quality that determine to connect and/or signal strength signal intensity whether deteriorated into and be lower than a predetermined threshold or worsening with speed greater than the threshold value of a selection.If answer to not, then this system transfer to 34 and inquiry on the link (that is, UL or DL) that the network operator selects, whether detect the SID frame of sufficient amount, be in the silent period and only generating comfortable noise to conclude that these wireless connections are current.If words that answer is yes, then this system transfers to 35 and also carries out switching.
If 33 determine signal qualitys and/or signal strength signal intensity deteriorated into be lower than a preselected threshold value or deterioration speed faster than a threshold value, then this system no longer determines by postponing to switch whether this wireless air interface is in the silent period, on the contrary, it is transferred to 35 immediately and also carries out switching to avoid losing the danger of connection.
Technology of the present invention can be applicable to once have only the bipartite wireless air interface of a link to connect.Select any bar link to use this technology based on network operator's selection and applicable to up link (UL) or down link (DL).Solution of the present invention shows as very significant effect for the audible effects that eliminate to switch and has eliminated reception to listened to the transition effects on one of selected link basically fully.
Next referring to Fig. 5, illustrate that up link that expression wherein connects for wireless air interface allows the DTX function and the DTX of timing diagram do not allow to(for) its down link.Usually, for those cellular systems network operator of current enforcement DTX, as Fig. 5 supposes, wherein in up link, implement this function for 90%.Its reason is that the real economy benefit of user's saving power of battery that slave transmitter is produced when speaking occurs in the mobile radio station, rather than occurs among the BTS.In addition, can to stop mobile radio station and BTS to carry out continually as usual signal quality measured for quality that the slow property of VAD operation can slight deterioration plosive (such as the sound of " p ", " t " and " k ") in the DTX system and DTX function.
In the up link of Fig. 3, the state of DTX " disconnected (off) " expression voice just send between mobile radio station and base station, and the user of the state of DTX " logical (on) " expression mobile radio station has silent period and only send the SID frame on the up link between mobile radio station and the base station.In order to simplify this example, the chart of Fig. 5 is also represented the calling between the user on mobile subscriber and the fixed telephone, yet, following reason for MS-MS call out also remain real.The dot-dash timeline that is labeled as " HO1 " is represented irrelevant with silent period and the time that switch, and " HO2 " is the time of adjusting switching timing according to the principle of the invention according to the silent period on the up link.Take place if all that may take place during mobile subscriber's voice cycle are originally switched all will be deferred to during silent period, shown in HO2, then " fix " user and will detect all these switchings in inaudible mode.In this case switching can always occur in that " fixing " user is speaking and since the mobile subscriber do not speaking and DTX is connecting and when receiving comfortable noise in receiver.Thereby the effect of this switching is inaudible for the side that fixes of communication.Yet the mobile subscriber does not listen and obtains handoff owing to implement the DTX function on down link (DL) in this case.All other prior aries as discussed above can be used to make voice interruption time minimum on this link to minimize audible effects.
Next referring to Fig. 6, it shows another timing diagram of explanation and opposite situation (although more uncommon in current actual conditions) shown in Figure 5.In Fig. 6, the DTX function is permitted for the down link that wireless air interface connects between two sides and does not allow to be used for its up link.Under the situation of this example, because up link is always sending, so it is more good to postpone switching according to down link.In this case, to be deferred to HO2 from HO1 (when not having DTX on up link or down link) in each switching that takes place during the voice cycle that is assumed to fixed-line subscriber on the down link, this moment, DTX was during the silent period that is operated in fixed-line subscriber on the down link.Thereby the mobile subscriber will can not detect any switching with hearing, and he receives only comfortable noise subsequently.On the contrary, switch when always occurring in the mobile subscriber and talking (or the people on the other end of this connection at least is in speech) and the mobile subscriber will no longer hear these switchings.In this case, " fix " user because the DTX function is not operated on the up link thereby will always hears handoff.In these cases, the cellular system network operator might not make its network that the good market competitiveness arranged aspect the quality owing to the mobile subscriber who is connected to its network can not detect voice interruption.
At last referring to Fig. 7, it is also with formal description another aspect of the present invention of timing diagram.In the case, if two users on supposition up link and the down link not simultaneously quietness speaking again, then each switching will occur in during the silent period of one of communicating pair.In the example of Fig. 7, when up link works, carry out handover event at mobile subscriber's quietness and DTX with timeline " HO1 " expression, and thereby " fixing " user can not notice this handover event.When utilizing the switching of dot-dash timeline " HO2 " expression to occur in " fix " user's quietness and DTX on down link, to activate, mobile subscriber so can not notice this switching audibly.Because such switching takes place often at random,, mobile subscriber and " fixing " user on average be about 50% handoff so will hearing.Postpone to switch by silent period, eliminate the handoff that to be perceived fully for mobile subscriber or " fixing " user, but be not to eliminate the handoff that perceives fully for the two according to one of link.Two sides are quiet (and DTX works on up link and down link simultaneously) and need the situation of execution switching to be actually a kind of rare cases during for the cycle of an expansion.The direction of this system optimization when system operator selects a special parameter to select DTX to work on both direction in current system, that is, and up link or down link.For example, if during " fixing " user's silent period, carry out all switchings, in any case then since the mobile subscriber can not experience again yet and anyly listen quality that interruption makes network seemingly to be enhanced from mobile subscriber's viewpoint.Call out for the MS-MS in the consolidated network, if carry out the same strategy that switches during using the silent period of down link, then mobile subscriber will hear the switching of other mobile radio stations and can't hear oneself switching.
Can understand describing above of the present invention: method and system of the present invention can be implemented in a different manner.In any situation, the audible effects that switches by a side or the opposing party among the both call sides of wireless air interface in the cellular wireless system can be sheltered fully and be discovered without any listening.Thereby this system has a large amount of advantages for system operator, and all these system operator all wish to strengthen the corresponding requirements to signal quality in its system.Along with channeling growing in the cellular system, method and system of the present invention becomes more and more important reducing to become aspect the irritating switching audible effects.
Though the preferred embodiment of method and apparatus of the present invention has been described in expression and in front the description in the accompanying drawings, should have understood to the invention is not restricted to disclosed embodiment and can carry out manyly rearranging, revising and replace and spirit of the present invention that the institute that do not deviate from following claims proposes and defines.
Claims (32)
1, be used for reducing a kind of method of the audible effects that switches in Traffic Channel at least one link of wireless air interface of cellular wireless system, may further comprise the steps:
Except wherein implementing discontinuous transmission (DTX) by detecting in the link whether each traffic frame in the described link be made of the audible effects that reduces switching voice, nontransparent basis or background noise the link;
Quiet descriptor (SID) frame that sends the relevant information of the background noise comprise therewith in the link from transmitter is given receiver, and detecting with response does not only have speech but also do not have non-transparent data to appear on the described link;
Monitor all incoming traffic frames in this receiver;
Detect the SID frame in this receiver, and upgrade comfortable noise characteristic in response and in this receiver, generate comfortable noise;
Determine to carry out the switching of mobile radio station on the described link to respond this intrasystem signal measurement;
Postpone the execution of described switching, until the SID frame that on this receiver, receives predetermined quantity continuously, generating voice or non-transparent data and receiving comfortable noise and carrying out of the switching of this mobile radio station subsequently in response with a Founder that is illustrated on this receiver from a BTS to another BTS.
2, the described method of claim 1 also comprises:
The quality that supervision is connected during the time cycle of detecting with the described SID frame of counting; With
Carry out described switching and no matter the quantity of the continuous SID frame that receives how, signal quality that connects with response or bit error rate (BER) deteriorate into and are lower than a preset value or worsen with a speed greater than preliminary election speed.
3, the described method of claim 1 also may further comprise the steps:
Trigger have the preliminary election timeout value in the described system timer to respond the reception of a SID frame; With
Carry out described switching and no matter the quantity of the SID frame that received how, reaches its timeout value to respond described timer.
4, the described method of claim 1 wherein utilizes speech activity detector (VAD) to carry out the detection whether each traffic frame in the described link is made of voice, non-transparent data or background noise.
5, the described method of claim 1 is wherein only implemented DTX on the up link of this cellular system.
6, the described method of claim 1 is wherein only implemented DTX on the down link of this cellular system.
7, the described method of claim 1 is wherein implemented DTX on the up link of this cellular system and down link.
8, be used for reducing a kind of method of the audible effects that the digital cellular wireless system switches, wherein at least one channel among the up link of this system or the downlink radio channel, implement discontinuous transmission (DTX), with interrupt that sending constantly the communication information in the wireless transmission of the first party on the described link and replace and send the periodicity that expression generates the rule of comfortable noise in should the receiver in second party and indicate to second party, the method comprises:
Supervision is by the transmission of indicating in that described periodicity that does not send in the first party that sends communication constantly;
Monitor in this system one of described side's of carrying out as described communication the needs of mobile radio station from a sub-district to the switching of another sub-district;
Postpone the execution of the switching of described needs, until from constantly receiving the regular periodicity indication of preselected number, to guarantee that second party receives only comfortable noise and the audible effects of the switching will be not can uppick do not carried out and carry out described switching subsequently in the first party that sends communication at that.
9, the method for the audible effects that switches in the described minimizing digital cellular of claim 8 wireless system, communicating by letter of carrying out between mobile radio station on one of wherein said link and the opposing party is voice call, and monitors that wherein the described step of the needs of the switching of carrying out described mobile radio station also comprises:
Monitor the speed that signal strength signal intensity and bit error rate (BER) on the up link of described mobile radio station and the down link and signal quality and BER are worsening;
The signal strength signal intensity of supervision and the deterioration speed of signal strength signal intensity are compared with corresponding preselected threshold value;
Carry out described switching and no matter whether receive the periodicity indication of the rule of described preselected number, the described deterioration speed that deteriorates into the signal strength signal intensity that is lower than described preselected threshold value or described supervision with the signal strength signal intensity that responds described supervision becomes greater than described threshold value.
10, the method for the audible effects that switches in the described minimizing digital cellular of claim 9 wireless system monitors that wherein the described step of the needs of the switching of carrying out described mobile radio station also comprises:
The deterioration speed of BER and BER is compared with corresponding preselected threshold value;
Carry out described switching and no matter whether receive the periodicity indication of the rule of described preselected number, the described deterioration speed that deteriorates into the BER that is lower than described preselected threshold value or described supervision with the BER that responds described supervision becomes greater than described threshold value.
11, the method for the audible effects of the described minimizing digital cellular of claim 8 wireless system, wherein only on the up link of described system, allow DTX, communicating by letter of carrying out between the mobile radio station on one of described up link and the opposing party is voice call, and wherein postpone the switching of described needs, described mobile radio station on this up link is not in speech, and only receiving comfortable noise with the opposing party of described mobile radio station conversation, with the audible effects of the switching of eliminating described the opposing party.
12, the method for the audible effects of the described minimizing digital cellular of claim 8 wireless system, wherein only on the down link of described system, allow DTX, communicating by letter of carrying out between the mobile radio station on one of described up link and the opposing party is voice call, and wherein postpone the switching of described needs, the opposing party that described mobile radio station on this up link is talked, conversed is only receiving comfortable noise in speech and described mobile radio station, with the audible effects of the switching of eliminating described mobile radio station.
13, the method for the audible effects that switches in the described minimizing digital cellular of claim 8 wireless system, wherein at least one channel among the up link of this system or the downlink radio channel, implement discontinuous transmission (DTX), wherein periodicity indication by the rule that sends that side who constantly sends communication has the form of a SID frame during each SACCH cycle, and the described step that wherein monitors the transmission of described periodicity indication comprises and monitoring and the quantity of counting from the continuous SID frame of described side's reception.
14, the method for the audible effects that switches in the described minimizing digital cellular of claim 8 wireless system, wherein at least one channel among the up link of this system or the downlink radio channel, implement discontinuous transmission (DTX), wherein indicate the form and the wherein said delay step that during each SACCH cycle, have a SID frame to comprise by the periodicity of the rule that sends that side who does not send communication constantly:
Counting is from the quantity of the continuous SID frame of described side's reception;
Described quantity and a preset value are compared; With
When described quantity surpasses described preset value, carry out this switching.
15, the method for the audible effects that switches in the described minimizing digital cellular of claim 8 wireless system, wherein at least one channel among the up link of this system or the downlink radio channel, implement discontinuous transmission (DTX), wherein utilize speech activity detector (VAD) to interrupt coming that described wireless transmission (VAD) that sends the side on the described link of communicating by letter constantly of leisure, this makes the periodicity indication of the rule of representing to generate comfortable noise in the opposing party's receiver is sent to the opposing party.
16, the method for the audible effects that switches in the described minimizing digital cellular of claim 9 wireless system, communicating by letter of wherein carrying out between the mobile radio station on one of described link and the opposing party is that non-transparent data is called out.
17, be used for reducing a kind of system of the audible effects that switches in Traffic Channel at least one link of wireless air interface of cellular wireless system, comprise:
Be used in a link except that the link that wherein will reduce the audible effects that switches, implementing the device of discontinuous transmission (DTX), comprise the device whether each traffic frame of being used for detecting a described link is made of voice, non-transparent data or background noise;
Being used for sending quiet descriptor (SID) frame comprise the information of background noise in relevant this link from transmitter gives receiver, detects with response and both do not have voice also not have non-transparent data to appear at device on the described link;
The device that is used for all incoming traffic frames of warning receiver;
Be used for detecting the SID frame of receiver and upgrade comfortable noise characteristic in response to this and in this receiver, generate the device of comfortable noise;
Be used to determine whether to carry out the switching of mobile radio station on the described link to respond the device of signal measurement in this system;
Be used to postpone the execution of described switching until generating voice or non-transparent data and receiving comfortable noise and carrying out the device for switching of this mobile radio station subsequently in response to this to represent the Founder on this receiver from a BTS to another BTS at the SID frame that receives preselected number on this receiver continuously.
18, the described system of claim 17 also comprises:
The device that is used for the quality that supervision is connected during the time cycle of detecting with the described SID frame of counting; With
Be used to carry out described switching and no matter the quantity of the continuous SID frame that received deteriorates into the device that is lower than a preset value or is worsening with the speed that is higher than a preliminary election speed as signal quality or the bit error rate (BER) that how responds this connection.
19, the described system of claim 17 also may further comprise the steps:
Be used to trigger the timer that has a preliminary election timeout value in the described system device with the reception that responds a SID frame; With
Be used to carry out described switching and no matter the quantity of the SID frame that received reaches the device of its timeout value as timer as described in how responding.
20, the described system of claim 17 wherein carries out the detection whether each traffic frame in the described link is made of voice, non-transparent data or background noise by speech activity detector (VAD).
21, the described system of claim 17 wherein only implements DTX on the up link of this cellular system.
22, the described method of claim 17 is wherein only implemented DTX on the down link of this cellular system.
23, the described method of claim 17 is wherein implemented DTX on the up link of this cellular system and down link.
24, be used for reducing a kind of system of the audible effects that the digital cellular wireless system switches, wherein at least one channel among the up link of this system or the downlink radio channel, implement discontinuous transmission (DTX), send the periodicity that expression generates the rule of comfortable noise in should the receiver in second party and indicate to second party to interrupt sending the wireless transmission of first party on the described link of communication constantly and replacing at that, described system comprises:
Be used to monitor device by the transmission of the described periodicity indication that sends in that first party that does not send communication constantly;
Be used in this system monitor that execution is one of described side's of described communication the device of a mobile radio station from a sub-district to the needs of the switching of another sub-district;
Be used for postponing execution that described needs switch until from the device of the periodicity indication of the rule that receives preselected number that communication one side who does not send the communication information constantly, only also carry out described switching subsequently to guarantee the opposing party at the audible effects that receives comfortable noise and switching that will not uppick execution.
25, the described system that is used for reducing the audible effects that the digital cellular wireless system switches of claim 24, communicating by letter of wherein carrying out between the mobile radio station on one of described link and the opposing party is voice call, and is used to wherein to monitor that the described device of the needs of the switching of carrying out described mobile radio station also comprises:
Be used to monitor the device of the speed that signal strength signal intensity and bit error rate (BER) on the up link of described mobile radio station and the down link and signal strength signal intensity and BER worsen;
The device that the deterioration speed that is used for the signal strength signal intensity that will monitor and signal strength signal intensity and corresponding preselected threshold value compare;
Be used to carry out described switching and become greater than the device of described threshold value with the described deterioration speed that the signal strength signal intensity that responds described supervision deteriorates into the signal strength signal intensity that is lower than described preselected threshold value or described supervision no matter whether receive the periodicity indication of the rule of described preselected number.
26, the described system that is used for reducing the audible effects that the digital cellular wireless system switches of claim 25 is used to wherein to monitor that the described device of the needs of the switching of carrying out described mobile radio station also comprises:
Be used for the device that speed that BER and BER are worsened and corresponding preselected threshold value compare;
Be used to carry out described switching and become greater than the device of described threshold value with the described deterioration speed that the BER that responds described supervision deteriorates into less than the BER of described preselected threshold value or described supervision no matter whether receive the periodicity indication of the rule of described predetermined quantity.
27, the described system that is used for reducing the audible effects that the digital cellular wireless system switches of claim 24, wherein only on the up link of described system, allow DTX, communicating by letter of carrying out between the mobile radio station on one of described up link and the opposing party is voice call, and wherein postpone the switching of described needs, described mobile radio station on this up link is not only receiving comfortable noise in speech and with the opposing party of described mobile radio station conversation, with the audible effects of the switching of eliminating described the opposing party.
28, the described system that is used for reducing the audible effects that the digital cellular wireless system switches of claim 24, wherein only on the down link of described system, allow DTX, communicating by letter of carrying out between the mobile radio station on one of described up link and the opposing party is voice call, and wherein postpone the switching of described needs, described mobile radio station on this up link is only receiving comfortable noise in speech and described mobile radio station the opposing party of speech, conversation, with the audible effects of the switching of eliminating described mobile radio station.
29, the described system that is used for reducing the audible effects that the digital cellular wireless system switches of claim 24, wherein at least one wireless channel among the up link of this system or the downlink radio channel, implement discontinuous transmission (DTX), wherein the periodicity indication by the rule that does not send that side who sends communication constantly has the form of a SID frame during each SACCH cycle, and the described device that wherein is used to monitor the transmission of described periodicity indication comprises and is used to monitor and counts from the device of the quantity of the continuous SID frame of described side reception.
30, the described system that is used for reducing the audible effects that the digital cellular wireless system switches of claim 24, wherein at least one wireless channel among the up link of this system or the downlink radio channel, implement discontinuous transmission (DTX), wherein the periodicity indication by the rule that does not send that side who sends the communication information constantly has the form of a SID frame during each SACCH cycle, and wherein said delay step comprises:
Be used to count device from the continuous SID number of frames of described side's reception;
With described quantity and the device that preset value compares; With
When surpassing described preset value, described quantity carries out described device for switching.
31, the described system that is used for reducing the audible effects that the digital cellular wireless system switches of claim 24, wherein at least one wireless channel among the up link of this system or the downlink radio channel, implement discontinuous transmission (DTX), wherein from not utilizing speech activity detector (VAD) to interrupt in that described wireless transmission that sends the side on the described link of the communication information constantly, this feasible expression should generate the rule of comfortable noise in the opposing party's receiver periodicity indication sends to the opposing party.
32, the described system that is used for reducing the audible effects that the digital cellular wireless system switches of claim 25, communicating by letter of wherein carrying out between the mobile radio station on one of described link and the opposing party is that non-transparent data is called out.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
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| US9336398A | 1998-06-08 | 1998-06-08 | |
| US09/093,363 | 1998-06-08 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN99809482A Pending CN1313017A (en) | 1998-06-08 | 1999-06-01 | System for elimination of audible effects of handover |
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| CN (1) | CN1313017A (en) |
| AU (1) | AU754698B2 (en) |
| BR (1) | BR9910993A (en) |
| CA (1) | CA2334195A1 (en) |
| GB (1) | GB2354409B (en) |
| WO (1) | WO1999065266A1 (en) |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100391120C (en) * | 2006-03-17 | 2008-05-28 | 凯明信息科技股份有限公司 | Method for detecting shift sequence under lack of distribution mode |
| WO2009036703A1 (en) * | 2007-09-17 | 2009-03-26 | Huawei Technologies Co., Ltd. | A method and apparatus for determining the downlink transmission mode |
| WO2010091546A1 (en) * | 2009-02-10 | 2010-08-19 | 华为技术有限公司 | Method for sending radio frames, base station and network system |
| WO2011009379A1 (en) * | 2009-07-20 | 2011-01-27 | 中国移动通信集团北京有限公司 | Method, apparatus and wireless communication system for controlling downlink discontinuous transmission state |
| CN101572090B (en) * | 2008-04-30 | 2013-03-20 | 向为 | Self-adapting multi-rate narrowband coding method and coder |
| CN101952887B (en) * | 2008-02-19 | 2013-05-29 | 西门子企业通讯有限责任两合公司 | Method and means for encoding background noise information |
| CN103703824A (en) * | 2013-03-05 | 2014-04-02 | 华为技术有限公司 | Treatment for business interruption and related device |
| WO2015192532A1 (en) * | 2014-06-20 | 2015-12-23 | 中兴通讯股份有限公司 | Method and apparatus for improving handover voice quality |
| CN105472671A (en) * | 2014-09-10 | 2016-04-06 | 中兴通讯股份有限公司 | Cell switching method in GSM system and base station device |
| CN105530668A (en) * | 2014-09-29 | 2016-04-27 | 中兴通讯股份有限公司 | Method, device and base station for channel switching |
| CN113438704A (en) * | 2020-03-23 | 2021-09-24 | 华为技术有限公司 | Switching method and device |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI116643B (en) * | 1999-11-15 | 2006-01-13 | Nokia Corp | Noise reduction |
| WO2006037372A1 (en) * | 2004-09-30 | 2006-04-13 | Telefonaktiebolaget Lm Ericsson (Publ) | Method for avoiding interruptions of push to talk services |
| FI120434B (en) * | 2005-02-08 | 2009-10-15 | Teliasonera Ab | Cell re-selection in cellular network based packet communication |
| JP4726652B2 (en) * | 2006-02-27 | 2011-07-20 | 株式会社エヌ・ティ・ティ・ドコモ | Base station and handover control method |
| GB0616537D0 (en) * | 2006-08-22 | 2006-09-27 | Siemens Ag | Method of handover |
| GB0920729D0 (en) | 2009-11-26 | 2010-01-13 | Icera Inc | Signal fading |
| US9497684B2 (en) | 2014-11-20 | 2016-11-15 | Qualcomm Incorporated | Radio access technology handover optimization in a push-to-talk session |
| US9794842B2 (en) | 2015-05-21 | 2017-10-17 | At&T Mobility Ii Llc | Facilitation of handover coordination based on voice activity data |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2713240B2 (en) * | 1995-06-15 | 1998-02-16 | 日本電気株式会社 | Mobile communication system |
| AU3916097A (en) * | 1996-08-26 | 1998-03-19 | Motorola, Inc. | Communication system with zero handover mute |
-
1999
- 1999-06-01 WO PCT/SE1999/000947 patent/WO1999065266A1/en active IP Right Grant
- 1999-06-01 GB GB0029763A patent/GB2354409B/en not_active Expired - Fee Related
- 1999-06-01 BR BR9910993-0A patent/BR9910993A/en not_active IP Right Cessation
- 1999-06-01 CA CA002334195A patent/CA2334195A1/en not_active Abandoned
- 1999-06-01 CN CN99809482A patent/CN1313017A/en active Pending
- 1999-06-01 AU AU46674/99A patent/AU754698B2/en not_active Ceased
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100391120C (en) * | 2006-03-17 | 2008-05-28 | 凯明信息科技股份有限公司 | Method for detecting shift sequence under lack of distribution mode |
| WO2009036703A1 (en) * | 2007-09-17 | 2009-03-26 | Huawei Technologies Co., Ltd. | A method and apparatus for determining the downlink transmission mode |
| CN101952887B (en) * | 2008-02-19 | 2013-05-29 | 西门子企业通讯有限责任两合公司 | Method and means for encoding background noise information |
| CN101572090B (en) * | 2008-04-30 | 2013-03-20 | 向为 | Self-adapting multi-rate narrowband coding method and coder |
| WO2010091546A1 (en) * | 2009-02-10 | 2010-08-19 | 华为技术有限公司 | Method for sending radio frames, base station and network system |
| WO2011009379A1 (en) * | 2009-07-20 | 2011-01-27 | 中国移动通信集团北京有限公司 | Method, apparatus and wireless communication system for controlling downlink discontinuous transmission state |
| CN103703824A (en) * | 2013-03-05 | 2014-04-02 | 华为技术有限公司 | Treatment for business interruption and related device |
| CN103703824B (en) * | 2013-03-05 | 2017-07-14 | 华为技术有限公司 | The processing method and relevant apparatus of service disconnection |
| WO2015192532A1 (en) * | 2014-06-20 | 2015-12-23 | 中兴通讯股份有限公司 | Method and apparatus for improving handover voice quality |
| CN105323803A (en) * | 2014-06-20 | 2016-02-10 | 中兴通讯股份有限公司 | Method and device for improving switch voice quality |
| CN105472671A (en) * | 2014-09-10 | 2016-04-06 | 中兴通讯股份有限公司 | Cell switching method in GSM system and base station device |
| CN105472671B (en) * | 2014-09-10 | 2019-04-09 | 中兴通讯股份有限公司 | The method and base station equipment of cell switching in a kind of gsm system |
| CN105530668A (en) * | 2014-09-29 | 2016-04-27 | 中兴通讯股份有限公司 | Method, device and base station for channel switching |
| CN113438704A (en) * | 2020-03-23 | 2021-09-24 | 华为技术有限公司 | Switching method and device |
Also Published As
| Publication number | Publication date |
|---|---|
| AU754698B2 (en) | 2002-11-21 |
| GB0029763D0 (en) | 2001-01-17 |
| GB2354409B (en) | 2003-01-22 |
| BR9910993A (en) | 2001-02-13 |
| GB2354409A (en) | 2001-03-21 |
| CA2334195A1 (en) | 1999-12-16 |
| AU4667499A (en) | 1999-12-30 |
| WO1999065266A1 (en) | 1999-12-16 |
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