CN1418445A - Use of silence detection for improved received voice quality during search of neighbor set - Google Patents
Use of silence detection for improved received voice quality during search of neighbor set Download PDFInfo
- Publication number
- CN1418445A CN1418445A CN 01806541 CN01806541A CN1418445A CN 1418445 A CN1418445 A CN 1418445A CN 01806541 CN01806541 CN 01806541 CN 01806541 A CN01806541 A CN 01806541A CN 1418445 A CN1418445 A CN 1418445A
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- China
- Prior art keywords
- signal
- search
- base station
- frequency
- vocoder
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/0005—Control or signalling for completing the hand-off
- H04W36/0083—Determination of parameters used for hand-off, e.g. generation or modification of neighbour cell lists
- H04W36/0085—Hand-off measurements
- H04W36/0088—Scheduling hand-off measurements
Abstract
A method of a mobile terminal searching signal strength of neighboring base stations within a cellular communications network. The method includes receiving a signal, transmitted at a first frequency, at a mobile terminal from a first base station. The received signal is processed at a signal processing unit within the mobile terminal. The received signal is analyzed and a period of silence within the signal is determined. Thereafter, the mobile teminal ceases signal processing and searches alternate frequencies of neighboring base stations and determines a signal strength measurement for each of the neighboring base stations. After performing the neighboring base station searching, the mobile terminal restores signal processing of the signal through the first base station at the first frequency.
Description
Invention field
The present invention relates to a kind of method of adjacent base station of searching for to determine the calling of conversing is switched, refer in particular to the quiet period of utilizing voice in the calling of conversing receive and finish search, reduce or eliminate because word or speech interrupt a kind of method of causing the speech mistake to distinguish to the alternative frequency of adjacent base station.
Background of invention
Code division multiple access (CDMA) portable terminal according to the TIA/EIA-95 standard should possess the mobile management of finishing or " plant maintenance " function.For this reason, portable terminal is searched for one group of adjacent base station or " pilot tone " constantly to determine wherein optimal one, and the tabulation of these base stations offers portable terminal by the base station.
When searching a certain adjacent pilot frequencies when being on the different CDMA frequency, the voice signal that is just carrying out on the work at present frequency is handled will be because of the intervention of new frequency and of short duration the stopping of measurement of pilot frequency intensity.Previous CDMA frequency be resumed with speech processes be allowed to continue before the used time in the speech of answering, produce one " hole ".In a preferred embodiment of the invention, before speech processes was recovered, the search of each frequency needed 20ms approximately.Therefore if when having a plurality of frequencies to search for, above-mentioned " hole " will become very big, and speech quality then can sharply descend, and may cause the understanding to words to change when being in certain syllable central just such as this cavity.
At present, cdma network adopts single-frequency to transmit signal mostly, so portable terminal does not need to search for other alternative frequency, therefore can not interrupt the processing of voice by force.But along with the expansion of network and the growth of number of users, the service supplier of CDMA has to adopt a plurality of frequencies.
Also there is same double-barreled question when searching for adjacent base station in time division multiple access (TDMA) network, the technology of dwindling the hole that adopts in tdma system at present is the scouting interval of staggering, do the overlapping that can reduce a plurality of cavities like this, reduce the puzzlement of problem in a way, but can not address this problem fully.
Therefore, be necessary to find a kind of method that cause the alternative frequency that the search adjacent base station of voice distortion sends can not for the calling of conversing.
Summary of the invention
The present invention utilizes spontaneous interruption in the talk to finish the ionization meter of the alternative frequency signal that adjacent base station is sent.Concerning the user, ionization meter at this moment carries out when interrupting talking, and can only produce the very little voice of answering that even can not make and produce distortion.
The present invention includes the following step:, come processing signals by digital signal processor by the receiver received signal.Phonological component in the signal is sent to vocoder, mails to loudspeaker plays again and listens to the user.The giving orders or instructions then of user earlier is sent to digital signal processor through vocoder, mails to the base station through transmitter again.In the processing procedure to receiving and transmitting signal, digital signal processor detects quiet period.And in quiet period, Signal Processing is suspended, then the intensity of the alternative frequency signal that sends of test adjacent base station has been so that determined whether the handoff candidate frequency, in case signal strength measurement work is finished, digital signal processor can recover the processing to receiving and transmitting signal again.
This method can provide the voice signal that sensuously links up for the user.During alternative frequency search, previously stored voice signal can be fed to vocoder, and with interruption noise or other interference that the user answers that influence that prevents to occur, the variable search cycle also can be further used for preventing tangible distortion.
Brief description
Fig. 1 is according to a kind of mobile network's sketch of the present invention;
Fig. 2 is each component units in the employed portable terminal among the present invention;
Fig. 3 is the flow chart of progressively finishing in cordless communication network the alternative frequency search of adjacent base station.
Detailed description of the Invention
In the following description, identical reference symbol is represented identical or corresponding part in several accompanying drawings.Referring now to illustration, the method that the present invention searches for the alternative frequency of adjacent base station is described.This method is very useful in the mobile communications network shown in Fig. 1.Include a plurality of base stations 12 with the mobile communications network of numbering 10 representatives, mobile services switching centre (MSC) 14 and other ground communication networks can be passed through in the base station, link to each other as public telephone switching network (PSTN) 18.Each base station 12 is seated in the region that is called Serving cell and for it provides service, common each Serving cell disposes a base station 12 in the mobile communications network 10 in the drawings.
In each sub-district, have a plurality of portable terminals 16, communicate by letter with base station 12 by Radio Link.Base station 12 allows the user of portable terminal 16 to communicate with one another or communicates with the user who is connected on the PSTN18.MSC 14 is responsible for going to for call routing or from portable terminal 16 by relevant base station 12.
Switching has just taken place in an ongoing calling commentaries on classics of being handled by first base station 12 when being handled by another base station 12.When the quality of received signal drops to acceptable below horizontally, and when having another available base stations that high-quality signal can be provided simultaneously, just need switch.Promoting the network management of power system capacity also may force ongoing calling to switch on second base station 12 of more active volumes from first base station 12.
Portable terminal 16 is finished the signal strength measurement to adjacent base station 12, so that determine when that according to TIA/EIA-95 needs switch.Begin or switch that current base station 12 can send one group of adjacent bast station list when finishing in per call, be commonly referred to adjacent cell list.Neighbor cell list is indicated the frequency of the adjacent base station 12 of potential switching target.Portable terminal continues the result to current base station 12 these measurements of report.Portable terminal 16 can also can be carried out measurement to signal strength signal intensity according to the variable cycle according to the fixed cycle.
The measurement report that is provided by portable terminal 16 is to 12 1 signal strength list from neighbor cell that measured on current location by portable terminal of current base station.10 of mobile communications networks know which adjacent cell still has unappropriated wireless channel can distribute use in switching.From these available channel list, mobile communications network 10 selects to be suitable for most handling the Serving cell of current calling from service quality and overall interference viewpoint.A suitable Traffic Channel of target BS 12 is distributed in selection, and make portable terminal 16 be tuned in the Target cell on the selected Traffic Channel.Meanwhile, MSC 14 also will call out from the base station 12 of current base station 12 converting into target sub-districts of service portable terminal.
Fig. 2 is illustrated in the portable terminal 16 that uses among the CDMA mobile network, includes: receive and send the receiver 102 that signal is used; Digital signal processor 104 is used for extracting voice data and providing information to vocoder 110 from received signal; Vocoder 110 is exported speech information by loud speaker 114; In order to send exhalation message, receive speech messages from microphone 112, convert digital coding to by vocoder 110, utilize audio stream on the spread spectrum expansion whole C dma channel 1.25MHz frequency band through digital signal processor 104 again; The output signal of vocoder 110 is sent to transmitter 116 and sends; CPU (CPU) 106 receives control/data-message, is used to control the function of portable terminal 16; Memory 107 can be stored the voice that receive at searching period, is sent to vocoder 110, hereinafter will be described.
The CDMA signal that receiver 102 receives quantizes and filtering through the Walsh code correlator, identifies in other signals from frequency band.In addition, this signal also needs to handle through the pseudo noise sequence correlator, and the pseudorandom PN sign indicating number so that elimination adds further sends signal or the same frequency from other and extracts desired signal.
Include voice/speech message and control/data-message in the signal that recovers.Voice/speech message is handled by the Viterbi decoder that is positioned at DSP 104, detects the mistake that produces in the also correction signal transmission.Preferably, after receiving the bit of predetermined quantity, DSP 104 decoded signals.Up to reach predetermined bit quantity or overtime still can not receive any additional signal after, the signal of arrival just is stored among the DSP 104.In a preferred embodiment of the invention, DSP104 continues approximately earlier to begin decoding again after 20ms receives the voice/speech data.After voice/speech message is in a single day decoded, just be sent to vocoder 110, so that convert the digital signal that receives to simulated audio signal by loud speaker 114 outputs.
Exhalation message is processed with an opposite process.The voice signal of receiving by microphone 112 is sent to vocoder 110 compressing and converting and becomes digital code.Message is fed to DSP 104 and utilizes the convolution coder coding then, carries out orthogonal coding with Walsh sign indicating number and PN sequence again, issues through transmitter 116 then and handles the base station 12 of calling out.
In the voice/speech message of transmitting-receiving, have spontaneous interruption between syllable in the conversation on course, words or sentence, or be called quiet period, do not have this moment the voice/speech data to need DSP104 to handle, these quiet period just can be used for searching for side frequency.Nearly all quiet period that produces in talk all is longer than search adjacent base station required time.
For the calling that receives, DSP 104 searching periods do not have speech/audio signal to be sent to vocoder 110.The signal storage that receives is handled after search work is finished in DSP 104 again.The signal interruption that is sent to vocoder 110 may in loud speaker 114, hear drone or bang.In addition, also may be changed by the background noise that the user awares conversation.For guaranteeing that above-mentioned search can not influence the user and answer, DSP 104 can be used as background noise and sent to vocoder 110 before being stored in voice/speech signal in the memory 107.By vocoder 110 with its be processed into minimal drone or bang output on the loud speaker 114.
For further guaranteeing that the search of the alternative frequency of adjacent base station is not influenced the user, DSP 104 can change the repetition period of search, for example, need detect two frequencies to the search of the first adjacent base station frequency, needs the search time of about 40ms altogether.The calling signal that DSP 104 handles a period of times earlier continues search again up to detecting another quiet period, so continue search second, third, the 4th and the 5th side frequency.This variable cycle reduced when being longer than quiet period search time by the user aware may.Variable repetition rate system is applied to time division multiple access (TDMA) portable terminal at present, and well-known in this area.
Fig. 3 has described each step of the present invention.During conversing, portable terminal 16 receives from the base station 12 signals of sending that comprise voice/speech message and control/data-message.These message are responsible for receiving and being sent to DSP 104 and handling (piece 300) by receiver 102.After receiving searching request, DSP 104 analyzes the voice/speech message (piece 310) of transmitting-receiving; If do not comprise quiet period (piece 320) in the message, then continue to analyze next voice/speech frame, determine whether to comprise quiet period.If DSP 104 has detected quiet period, carry out the side frequency search with regard to the processing that temporarily stops voice/speech message, in the suspending period of this section Message Processing, can give vocoder 110 processing the background noise that is stored in the memory 107, to prevent to output to acoustically inconsistent (piece 330) of loud speaker.
DSP 104 changes the current operating frequency that is used for receiving and transmitting signal to finish search, and receiver 102 receives signal and the channel quality measurement in the side frequency tabulation, as intensity, (pieces 340) such as BER and WER.After side frequency detected and finishes, receiver went back to previous CDMA frequency, and receiving and transmitting signal is handled and also recovered (piece 350).Channel quality measurements is sent to base station 12, so that judge when current ongoing calling is switched to (piece 360) on certain adjacent base station.
The present invention is described with regard to cdma network, is applicable to other networks too, comprises TDMA and frequency division multiple access (FDMA) network.All comprise the signal processing unit that is used to handle receiving and transmitting signal in these networks, these signal processing units all possess the function of judging quiet period in the receiving and transmitting signal, so that utilize these quiet period to carry out the search of adjacent base station, finish these search work and can not cause receiving and dispatching the influence of voice/speech message.
Read the those skilled in the art that describe with reference to above invention and can carry out various improvement and variation, and can not depart from the limited range of following claims.
Claims (14)
1. the method for a mobile terminal to search neighbor base station signal intensity in the cdma cellular mobile network comprises:
Receive the signal that sends with first frequency from first base station at portable terminal;
At the signal processing unit processes signal;
Determine the quiet period in the signal;
Afterwards, at least one alternative frequency signal of at least one adjacent base station is searched in the processing of stop signal;
After searching at least one alternative frequency, recover first frequency Signal Processing through first base station.
2. method as claimed in claim 2, wherein outputing to the user's voice signal is unremitting continuous signal.
3. method as claimed in claim 2 sends the voice of storage to vocoder when also being included in the alternative frequency of search.
4. method as claimed in claim 1 also is included in and determines to receive the request of searching for alternative frequency before the quiet period.
5. method as claimed in claim 1, wherein quiet period comprises transmission and receives message.
6. method as claimed in claim 1, wherein variable repetition rate is adopted in the adjacent base station search.
7. method as claimed in claim 1, wherein quiet period is formed by the interruption naturally that produces in talking.
8. carry out the method for the alternative frequency search of adjacent base station in the cdma wireless communication network, comprise the following steps:
Receive the signal of first frequency at portable terminal;
By the digital signal processor processes signal;
Message after transmission is handled is to vocoder;
Determine the quiet period in the received signal, stop the message after vocoder sends processing;
Search for the candidate BS that at least one works in second frequency, finish signal strength measurement;
After finishing the search candidate BS, the message after transmission is handled is to vocoder.
9. method as claimed in claim 8 is finished the message that sends after the search of alternative frequency after handling to vocoder, to generate unremitting voice output in quiet period.
10. method as claimed in claim 8 when also being included at least one candidate BS of search, sends previous speech message to vocoder.
11. method as claimed in claim 8, wherein the step of definite quiet period comprises the quiet period of the signal of determining transmitting-receiving.
12. the method for the alternative frequency of test comprises the following steps: in the cdma wireless communication network
Receive the calling signal at receiver;
At digital signal processor processes calling signal;
Calling signal after send handling from digital signal processor is to vocoder;
In the digital signal processor processes message of giving orders or instructions;
Determine quiet period in the calling signal and the signal of giving orders or instructions at digital signal processor;
Carry out alternative frequency test; And
After finishing alternative frequency test, send the calling signal to vocoder and in digital signal processor processes outgoing message from digital signal processor.
13., wherein after the request of receiving the alternative frequency of test, determine the quiet period in the calling signal and the signal of giving orders or instructions again as the method for claim 12.
14., wherein during the alternative frequency of search, stop to send the calling signal after handling and stopping to handle outgoing message to vocoder from digital signal processor as the method for claim 12.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US52530900A | 2000-03-14 | 2000-03-14 | |
| US09/525,309 | 2000-03-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1418445A true CN1418445A (en) | 2003-05-14 |
Family
ID=24092717
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 01806541 Pending CN1418445A (en) | 2000-03-14 | 2001-02-08 | Use of silence detection for improved received voice quality during search of neighbor set |
Country Status (3)
| Country | Link |
|---|---|
| CN (1) | CN1418445A (en) |
| AU (1) | AU2001236759A1 (en) |
| WO (1) | WO2001069962A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101175312B (en) * | 2006-11-03 | 2010-08-25 | 华为技术有限公司 | Channel detecting and switching method, base station and system |
| CN102281541A (en) * | 2010-06-13 | 2011-12-14 | 华为技术有限公司 | Silent period synchronization method and device |
| CN101529734B (en) * | 2006-10-26 | 2014-12-24 | 高通股份有限公司 | Method and device for silencing intervals in wireless communications |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100810247B1 (en) * | 2004-03-05 | 2008-03-06 | 삼성전자주식회사 | Method and apparatus for allocation of channel in a orthogonal frequency division multiple access system |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6044270A (en) * | 1995-10-18 | 2000-03-28 | Telefonaktiengesellschaft Lm Ericsson | Apparatuses and methods for signal strength measurement in a wireless communication system |
| DE59609110D1 (en) * | 1996-01-04 | 2002-05-23 | Siemens Ag | METHOD AND ARRANGEMENT FOR TRANSMITTING DATA IN A CELLULAR RADIO SYSTEM |
| US5987012A (en) * | 1996-12-19 | 1999-11-16 | Motorola, Inc. | Method of handing off and a wireless communication device |
-
2001
- 2001-02-08 AU AU2001236759A patent/AU2001236759A1/en not_active Abandoned
- 2001-02-08 CN CN 01806541 patent/CN1418445A/en active Pending
- 2001-02-08 WO PCT/US2001/004013 patent/WO2001069962A1/en active Application Filing
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101529734B (en) * | 2006-10-26 | 2014-12-24 | 高通股份有限公司 | Method and device for silencing intervals in wireless communications |
| CN101175312B (en) * | 2006-11-03 | 2010-08-25 | 华为技术有限公司 | Channel detecting and switching method, base station and system |
| CN102281541A (en) * | 2010-06-13 | 2011-12-14 | 华为技术有限公司 | Silent period synchronization method and device |
| WO2011157163A1 (en) * | 2010-06-13 | 2011-12-22 | 华为技术有限公司 | Method and device for quiet period synchronization |
| CN102281541B (en) * | 2010-06-13 | 2014-04-16 | 华为技术有限公司 | Silent period synchronization method and device |
Also Published As
| Publication number | Publication date |
|---|---|
| AU2001236759A1 (en) | 2001-09-24 |
| WO2001069962A1 (en) | 2001-09-20 |
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| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |