WO1998009454A1 - Systeme de communication avec periode de silence nulle lors du transfert - Google Patents

Systeme de communication avec periode de silence nulle lors du transfert Download PDF

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Publication number
WO1998009454A1
WO1998009454A1 PCT/US1997/014409 US9714409W WO9809454A1 WO 1998009454 A1 WO1998009454 A1 WO 1998009454A1 US 9714409 W US9714409 W US 9714409W WO 9809454 A1 WO9809454 A1 WO 9809454A1
Authority
WO
WIPO (PCT)
Prior art keywords
communication
voice
handover
communication device
station
Prior art date
Application number
PCT/US1997/014409
Other languages
English (en)
Inventor
Jean Khawand
David R. Heeschen
Original Assignee
Motorola Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Motorola Inc. filed Critical Motorola Inc.
Priority to AU39160/97A priority Critical patent/AU3916097A/en
Publication of WO1998009454A1 publication Critical patent/WO1998009454A1/fr

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Classifications

    • 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

Definitions

  • This invention is generally related to communication systems and more particularly to systems having a number of control stations.
  • a mobile communication device can communicate with other communication devices while traveling from the zone of one central station (serving cell) to that of another (target cell).
  • serving cell central station
  • target cell another central station
  • a problem that is often encountered in such systems is the muting of the voice that is experienced by a user during a handover.
  • Handover is the period of time during which the communication is handed over from the serving cell to the target cell.
  • the handover process requires that the mobile unit leave the serving cell and adjust to the new timing requirements of the target cell (synchronization). Further, the mobile unit must notify the target cell of its presence thereon.
  • the telephone call must be routed by the fixed network to the target cell for routing to the mobile unit.
  • the present methods of reducing the handover mute utilize fast execution routines to rapidly accomplish the handover. Regardless of the speed of the handover process, one can see that the possibility of a mute is not diminished and only the duration of the mute is reduced.
  • FIG. 1 shows a communication system in accordance with the present invention.
  • FIG. 2 shows a flow diagram of the operation of the handover procedure in accordance with the present invention.
  • FIG. 3 shows the details of a subroutine of the flow diagram of FIG. 2 in accordance with the present invention.
  • FIG. 4 shows a timeline of the activities that take place to eliminate handover mute in accordance with the present invention.
  • FIG. 5 shows a timeline of the activities that take place to minimize handover mute in accordance with the present invention.
  • the process of handing over the communication between two devices which communication goes through a Fixed Network Equipment includes a significant drawback.
  • FNE Fixed Network Equipment
  • a device moves out of the coverage zone of a first central station (serving cell) to that of a second central station (target cell) a handover of the call in progress is necessary.
  • This handover often causes muting of the audio communicated between the two communication devices.
  • the present invention eliminates this mute period by first searching for non-voice activity and then proceeding with the handover. The handover is therefore transparent to the users. The details of this procedure will be better understood by referring to a series of drawings where like numerals are carried forward.
  • the system 100 includes at least one wireless communication device as represented by 112 which communicates to at least one additional communication device represented by a second communication device 111 via first and second central stations 102 and 110.
  • the second communication device may be a land line device such as a telephone or a second wireless device such as a cellular phone.
  • the system 100 is shown without switching stations that may be needed, particularly if the device 111 is a landline unit.
  • Central station 102 is depicted as the serving cell which means that the communication between device 112 and 111 is conducted through this station when the need to switch to a second station is presented.
  • the second station is depicted by the target cell 110 which is the station that the communication is transferred to as the signal conditions demand.
  • the communication device 112 maintains connection to the two central stations, often referred to as Fixed Network Equipment FNE, via Radio Frequency RF links 105 and 107 as established and maintained via antennas 104, 106, 108.
  • the communication device 112 monitors other cells while it is connected to the serving cell 102.
  • the communication device 112 selects another cell, the target cell 110, which has superior RF signal quality.
  • the serving cell 102 informs the communication device 112 to switch to a suitable second control station.
  • the target cell is referred to as the serving cell.
  • the present invention aims to minimize and in most instances eliminate the handover mute that results as the communication is migrated from cell 102 to cell 110.
  • the communication device 112 is comprised of a modem 114, an audio processing block 116, and a channel manager 118.
  • the modem 114 encodes and decodes the data that is transmitted and received via the antenna 106. It sends and receives voice data to and from the audio processing block 116.
  • the audio processing block 116 in turn presents the user with audio via the speaker 122 and captures audio from the user via the microphone 120.
  • the channel manager 118 receives RF signal quality information from the modem 114 and transmits channel access information such as handover requests to the modem 114.
  • the channel manager 118 monitors inbound and outbound voice activity from the audio processing block 116 so that it may schedule handovers when zero handover mute times will be possible.
  • DSP Digital Signal Processor
  • the process is begun at the start point 202 whenever the channel manager is invoked. It first checks to see if a handover command has been received from the FNE 204. Normally, conditions are such that a handover is not required and therefore the result of the check 204 is "NO" so that the flow continues on and checks 206 to see if a previous handover command is pending or one has been flagged. Again, when conditions are such that a handover is not required, the "NO" result causes the channel manager to continue with other unspecified tasks. When a pending handover is flagged and/or is in queue, the operation continues with block 210 which is explained later in conjunction with the main flow of the diagram 200.
  • the detection as to whether a handover is needed may be via a demand generated by the device 112 or the stations 102 or 110.
  • the need for a handover may be established by having the serving station 102 measure the delay associated with an outbound or inbound signal. Alternatively, the signal strength of inbound or outbound signals may be evaluated to determine if a handover is needed.
  • the condition block 204 When a handover command is received, the condition block 204 yields a "YES" which starts the handover processing.
  • a forced handover timer is begun, 208. The purpose of this timer is to keep the channel manager from waiting too long for a zero audio mute handover opportunity since the FNE (serving 102 and target 110) expects handovers to be completed within a set time limit. If the handover is not completed on the first attempt the channel manager will run again but since the handover command was previously received the timer will not be restarted since the flow will avoid this by passing through the handover pending block 206.
  • the channel manager will update its status of inbound and outbound non-voiced frames via a subroutine block 210. The details of this update are contained in FIG. 3.
  • the channel manager checks 212 to see if the forced handover timer has expired. This condition occurs when no pauses or pauses of insufficient duration have been detected.
  • the communication device 112 must perform the handover immediately to satisfy the FNE's time limit on handovers and get whatever audio mute that occurs. In this case, the "YES " path is taken and the handover is performed 216.
  • the serving station 102 informs the communication device 112 to continue communicating with the device 111 through the target station 110.
  • the "NO" path is taken where the channel manager checks to see if the correct number of inbound (N) and outbound (M) non-voiced frames have occurred, block 214.
  • a limit for each is maintained by the communication device 112 which, if achieved, predicts that a natural pause is occurring in the conversation and that the time is ripe for the handover. If the limits have been achieved then the "YES" path is taken and the handover is performed, 216. This is the most desirable path for the handover mute algorithm to take as no mute is experienced by the system. Otherwise the "NO" path is taken and channel will re-evaluate its handover opportunity on its next invocation. The re-evaluation will occur until an opportunity is presented or the forced handover timer expires.
  • parameters N and M may be fixed for a particular application or may take configurable formats. These parameters may be stored in volatile or non- volatile, programmable or non-programmable memory devices. These parameters may be established dynamically by monitoring the natural pauses, such as voice nulls or inter-syllabic pauses, in a person's speech.
  • the communication device 112 may include an algorithm by which the user produced inadvertent and inter-syllabic pauses are monitored to determine their average time span. Depending on the speed with which a handover can be completed in a particular system, this adaptively measured pause time may be used to complete the handover without seeking advertent pauses in the communication.
  • FIG. 3 shows the blocks of the "update silence period" subroutine 210. Its purpose is to count the number of consecutive non -voiced frames in both the inbound and outbound direction. It is noted that having a number of consecutive non-voiced frames is an indicator of a natural pause in the conversation which is the most opportune time to perform a handover.
  • the first step is to check if the inbound frame is voiced or non- voiced, 302.
  • the audio processing block 116 of FIG. 1 provides this information to the channel manager 118 as it prepares the audio sampled by the microphone 120 and determines if voice was present or not. If voice is detected the "NO" path is taken and the counter of inbound non-voiced frames is reset, 306. Otherwise, no voice is detected and the "YES" path is taken thus incrementing the inbound non-voiced frame counter, 304.
  • the audio processing circuit 116 of provides this information to the channel manager 118 as it processes data received from the FNE and determines if voice is contained therein. If voice is detected, the "NO" path is taken and the counter of outbound non -voiced frames is reset, 312. Otherwise, no voice is detected and the "YES" path is taken thus incrementing the outbound non- voiced frame counter, 310. Finally, the silence period is calculated by monitoring the number of consecutive inbound and outbound non-voice frames that have occurred, 314. The goal at this juncture is to make sure that the number of non- voice frames in each direction is sufficient for a handover to take place without a mute. This step is highly dependent on the capabilities of the system 100 in completing a handover.
  • block 316 returns the control to block 212 in FIG. 2.
  • FIGs. 4 through 5 show the activities that take place as time is progressed in order to minimize the mute time when a handover is desired.
  • FIG. 4 a timing diagram of a handover that occurs during a natural non-voiced portion of a conversation is presented. This timeline begins with either inbound or outbound voice activity on the serving cell, 402. During this time 402 a handover command (assignment) 404 is received by the communication device 112. The communication device 112 begins its search for consecutive non-voiced frames and starts the forced handover timer, 420.
  • this timer is maintained to avoid missing a handover simply because a sufficient number of consecutive non-voiced frame were not detected. In other words, it is desired to handover with a mute than not to handover at all which results in the loss of communication.
  • the silence detection period SDP
  • the actual pause in the voice 408 will extend beyond the SDP and the handover; this is the desired result of the present invention.
  • the handover and the associated mute 410 take place. Indeed, the handover is started 412 following the SDP and is noted complete by the end handover ticker 414. During this handover period the speaker 122 is muted, 410. Since the handover mute occurs during the natural voice pause it is not noticed by the parties involved in the conversation and in fact has a significant margin for error, 411.
  • FIG. 5 shows a timing diagram of a handover that occurs during a short natural non-voiced portion of a conversation. It begins similarly to the timing diagram of FIG. 4 where an inbound or outbound voice is in progress using the serving cell 102. Because the voice pause 508 is short, the handover period which starts at the end of SDP 506 as shown by 512 extends beyond the non-voice activity and ends, 514 when the target cell 110 has taken over the communication, 516. In other words, the handover runs into the next voiced frame thus causing some unwanted lost audio 511. The lost audio is less than the entire duration of the handover and is still beneficial. This is significant as the handover mute is minimized when non-voice activity does not continue for a sufficiently long period of time.
  • a handover mute elimination/minimization procedure is presented whereby the switching from a serving cell to a target cell in a multi-cell communication system is accomplished with minimum impact on the conversation between the parties.
  • the system searches for the presence of non- voice activity.
  • the absence of voice activity is then acted upon by the system to initiate and complete the handover. Since no conversation is taking place, the handover is transparent to the users.
  • the handover is preferably implemented in a shorter period of time than the length of the non-voice activity. This condition eliminates muting of the voice during the handover.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Un système de communication (100) permet d'éliminer la période de silence qui survient lors du transfert quand le passage d'une cellule de desserte (102) à une cellule cible (110) est désiré. Une fois le besoin de transfert détecté (404), le système (100) recherche la présence d'une activité non vocale (406), puis utilise l'absence d'activité vocale pour lancer (412) et réaliser (414) le transfert. Comme il n'y a pas de conversation, les utilisateurs ne remarquent pas la période de silence.
PCT/US1997/014409 1996-08-26 1997-08-15 Systeme de communication avec periode de silence nulle lors du transfert WO1998009454A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU39160/97A AU3916097A (en) 1996-08-26 1997-08-15 Communication system with zero handover mute

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US70312296A 1996-08-26 1996-08-26
US08/703,122 1996-08-26

Publications (1)

Publication Number Publication Date
WO1998009454A1 true WO1998009454A1 (fr) 1998-03-05

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PCT/US1997/014409 WO1998009454A1 (fr) 1996-08-26 1997-08-15 Systeme de communication avec periode de silence nulle lors du transfert

Country Status (2)

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AU (1) AU3916097A (fr)
WO (1) WO1998009454A1 (fr)

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999065266A1 (fr) * 1998-06-08 1999-12-16 Telefonaktiebolaget Lm Ericsson (Publ) Systeme d'elimination d'effets audibles d'un transfert
EP1005177A2 (fr) * 1998-11-27 2000-05-31 Nec Corporation Méthode et appareil de commande d'un détecteur dans un système de communication CDMA
WO2000031996A2 (fr) * 1998-11-24 2000-06-02 Telefonaktiebolaget Lm Ericsson (Publ) Signalisation efficace dans la bande de base pour la transmission discontinue et les modifications de configuration dans des systemes de communication adaptatifs a debits multiples
US6148206A (en) * 1998-12-16 2000-11-14 Motorola, Inc. Method for concealing a handover mute
WO2000074429A1 (fr) * 1999-06-01 2000-12-07 Motorola Inc. Procede de transfert continu entre des reseaux de communications
EP1081969A1 (fr) * 1999-08-31 2001-03-07 Lucent Technologies Inc. Système de transfert de communication dans un réseau de communication radio cellulaire
EP1098540A1 (fr) * 1998-07-15 2001-05-09 Hitachi, Ltd. Procede de commutation d'une ligne occupee dans un reseau de communication mobile
US6360099B1 (en) * 2000-06-09 2002-03-19 Motorola, Inc. Reducing audio gaps during a communication network handoff
EP1479250A1 (fr) * 2002-02-28 2004-11-24 Nokia Corporation Systeme et procede de transfert sans interruption dans un terminal mobile
WO2006048349A1 (fr) * 2004-11-03 2006-05-11 Siemens Aktiengesellschaft Procede pour emettre un flux de donnees utiles et terminal de communication pour la reception et l'emission d'un flux de donnees utiles
KR100770819B1 (ko) * 1998-11-24 2007-10-26 텔레호낙티에볼라게트 엘엠 에릭슨(피유비엘) 통신 시스템에서 불연속 전송을 실행하기 위한 방법 및 시스템
EP1991012A1 (fr) * 2006-02-27 2008-11-12 NTT DoCoMo, Inc. Station de base et procede de commande de transfert
CN100456877C (zh) * 1999-05-11 2009-01-28 日本无线株式会社 用于phs个人台的越区切换方法
US7639639B2 (en) * 2005-08-01 2009-12-29 Ntt Docomo, Inc. Method for relaying information received via a first channel to a second channel and relay apparatus
WO2011064055A1 (fr) 2009-11-26 2011-06-03 Icera Inc Dissimulation d'interruptions audio
CN105530668A (zh) * 2014-09-29 2016-04-27 中兴通讯股份有限公司 一种信道切换方法、装置和基站
EP3193535A4 (fr) * 2014-09-10 2017-08-09 ZTE Corporation Procédé de transfert de cellule dans un système gsm et dispositif de station de base
US9794842B2 (en) 2015-05-21 2017-10-17 At&T Mobility Ii Llc Facilitation of handover coordination based on voice activity data
US11917469B2 (en) 2019-12-10 2024-02-27 Sennheiser Electronic Gmbh & Co. Kg Apparatus for the configuration of a wireless radio connection and method of configuring a wireless radio connection

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US5457680A (en) * 1993-05-18 1995-10-10 International Business Machines Corporation Data gateway for mobile data radio terminals in a data communication network
US5488649A (en) * 1994-05-06 1996-01-30 Motorola, Inc. Method for validating a communication link

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Cited By (39)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2354409A (en) * 1998-06-08 2001-03-21 Ericsson Telefon Ab L M System for elimination of audible effects of handover
WO1999065266A1 (fr) * 1998-06-08 1999-12-16 Telefonaktiebolaget Lm Ericsson (Publ) Systeme d'elimination d'effets audibles d'un transfert
GB2354409B (en) * 1998-06-08 2003-01-22 Ericsson Telefon Ab L M System for elimination of audible effects of handover
AU754698B2 (en) * 1998-06-08 2002-11-21 Telefonaktiebolaget Lm Ericsson (Publ) System for elimination of audible effects of handover
EP1098540A4 (fr) * 1998-07-15 2005-10-12 Hitachi Ltd Procede de commutation d'une ligne occupee dans un reseau de communication mobile
EP1098540A1 (fr) * 1998-07-15 2001-05-09 Hitachi, Ltd. Procede de commutation d'une ligne occupee dans un reseau de communication mobile
WO2000031996A3 (fr) * 1998-11-24 2000-08-10 Ericsson Telefon Ab L M Signalisation efficace dans la bande de base pour la transmission discontinue et les modifications de configuration dans des systemes de communication adaptatifs a debits multiples
US7500018B2 (en) 1998-11-24 2009-03-03 Telefonaktiebolaget L M Ericsson (Publ) Efficient in-band signaling for discontinuous transmission and configuration changes in adaptive multi-rate communications systems
KR100770819B1 (ko) * 1998-11-24 2007-10-26 텔레호낙티에볼라게트 엘엠 에릭슨(피유비엘) 통신 시스템에서 불연속 전송을 실행하기 위한 방법 및 시스템
AU766016B2 (en) * 1998-11-24 2003-10-09 Telefonaktiebolaget Lm Ericsson (Publ) Efficient in-band signaling for discontinuous transmission and configuration changes in adaptive multi-rate communications systems
WO2000031996A2 (fr) * 1998-11-24 2000-06-02 Telefonaktiebolaget Lm Ericsson (Publ) Signalisation efficace dans la bande de base pour la transmission discontinue et les modifications de configuration dans des systemes de communication adaptatifs a debits multiples
EP1005177A3 (fr) * 1998-11-27 2003-08-06 Nec Corporation Méthode et appareil de commande d'un détecteur dans un système de communication CDMA
EP1005177A2 (fr) * 1998-11-27 2000-05-31 Nec Corporation Méthode et appareil de commande d'un détecteur dans un système de communication CDMA
US6148206A (en) * 1998-12-16 2000-11-14 Motorola, Inc. Method for concealing a handover mute
CN100456877C (zh) * 1999-05-11 2009-01-28 日本无线株式会社 用于phs个人台的越区切换方法
WO2000074429A1 (fr) * 1999-06-01 2000-12-07 Motorola Inc. Procede de transfert continu entre des reseaux de communications
US6614769B1 (en) 1999-06-01 2003-09-02 Motorola, Inc. Communications unit for seamless handover between networks and method of use therefor
FR2794596A1 (fr) * 1999-06-01 2000-12-08 Motorola Inc Unites de telecommunications permettant un transfert invisible entre des reseaux et son procede d'utilisation
EP1081969A1 (fr) * 1999-08-31 2001-03-07 Lucent Technologies Inc. Système de transfert de communication dans un réseau de communication radio cellulaire
US6647262B1 (en) 1999-08-31 2003-11-11 Lucent Technologies Inc. Cellular radio communication handover systems
US6360099B1 (en) * 2000-06-09 2002-03-19 Motorola, Inc. Reducing audio gaps during a communication network handoff
EP1479250A1 (fr) * 2002-02-28 2004-11-24 Nokia Corporation Systeme et procede de transfert sans interruption dans un terminal mobile
EP1479250A4 (fr) * 2002-02-28 2007-04-11 Nokia Corp Systeme et procede de transfert sans interruption dans un terminal mobile
CN100358371C (zh) * 2002-02-28 2007-12-26 诺基亚公司 用于在移动终端中的无中断切换的系统和方法
US8270366B2 (en) 2004-11-03 2012-09-18 Siemens Enterprise Communications Gmbh & Co. Kg Method for outputting a useful data stream and communications terminal for receiving and for outputting a useful data stream
WO2006048349A1 (fr) * 2004-11-03 2006-05-11 Siemens Aktiengesellschaft Procede pour emettre un flux de donnees utiles et terminal de communication pour la reception et l'emission d'un flux de donnees utiles
US7639639B2 (en) * 2005-08-01 2009-12-29 Ntt Docomo, Inc. Method for relaying information received via a first channel to a second channel and relay apparatus
EP1991012A4 (fr) * 2006-02-27 2012-08-29 Ntt Docomo Inc Station de base et procede de commande de transfert
EP1991012A1 (fr) * 2006-02-27 2008-11-12 NTT DoCoMo, Inc. Station de base et procede de commande de transfert
US8666413B2 (en) 2006-02-27 2014-03-04 Ntt Docomo, Inc. Base station and handover control method
WO2011064055A1 (fr) 2009-11-26 2011-06-03 Icera Inc Dissimulation d'interruptions audio
DE112010004574T5 (de) 2009-11-26 2012-11-22 Icera Inc. Verbergen von Audio-Unterbrechungen
EP3193535A4 (fr) * 2014-09-10 2017-08-09 ZTE Corporation Procédé de transfert de cellule dans un système gsm et dispositif de station de base
CN105530668A (zh) * 2014-09-29 2016-04-27 中兴通讯股份有限公司 一种信道切换方法、装置和基站
EP3203778A4 (fr) * 2014-09-29 2017-10-04 ZTE Corporation Procédé et dispositif de commutation de canal, station de base
US9794842B2 (en) 2015-05-21 2017-10-17 At&T Mobility Ii Llc Facilitation of handover coordination based on voice activity data
US10219192B2 (en) 2015-05-21 2019-02-26 At&T Mobility Ii Llc Facilitation of handover coordination based on voice activity data
US10743222B2 (en) 2015-05-21 2020-08-11 At&T Mobility Ii Llc Facilitation of handover coordination based on voice activity data
US11917469B2 (en) 2019-12-10 2024-02-27 Sennheiser Electronic Gmbh & Co. Kg Apparatus for the configuration of a wireless radio connection and method of configuring a wireless radio connection

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