CN1242919A - Simulcast handoff method compensating for cable length differences - Google Patents
Simulcast handoff method compensating for cable length differences Download PDFInfo
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- CN1242919A CN1242919A CN 97181185 CN97181185A CN1242919A CN 1242919 A CN1242919 A CN 1242919A CN 97181185 CN97181185 CN 97181185 CN 97181185 A CN97181185 A CN 97181185A CN 1242919 A CN1242919 A CN 1242919A
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Abstract
The invention relates to a transmission method and a cellular radio system comprising base stations and at least one vocoder, in which cellular radio system)the base stations and the vocoder transmit to each other a signal, the base stations transmitting signals to be vocoder substantially simultaneously, and wherein the vocoder receives the substantially simultaneously transmitted signals at different moments of reception, the cellular radio system comprising measuring means for measuring the delay difference between the different moments of reception of the signals received by the vocoder, and delaying means for delaying, if required, the signals to be transmitted to the base stations in such a way that the base stations receive the signals transmitted by the vocoder substantially simultaneously.
Description
The present invention relates generally to telecommunication system.Or rather, the present invention relates to adopt the digital cellular radio system of soft handover.
Typical cellular radio system comprises the fixed base stations network, and the user terminal of communicating by letter with one or more network base stations.The communication information that arrives from user terminal is transmitted in the base station.When moving or keeping static, subscriber board both can send message mutually by the base station, also can send the user terminal of message to other telephone system.When user terminal is positioned at the area of coverage of base station network, can send message.The business of user terminal in order to use cellular radio system to provide, under any circumstance it all should be maintained to the connection of at least one base station.
When user terminal do not use base station network and provided professional the time, it does not need the connection of base station network, but monitors the base station under idle pulley.When user terminal in base station network when the area of coverage of a base station moves to the area of coverage of another base station, need to change channel or base station.
Although under the particular case, for example user terminal can be simultaneously and a plurality of base station communications in cdma system, in typical cellular radio system, user terminal once only with a base station communication.In the soft handover of prior art,, still be maintained to the connection of base station network although handover occurs.In this handover, change the base station usually.Prior art also comprises softer handover, does not wherein change the base station, but changes used base station section.Soft handover and softer handover are called as the handover of finishing type before the interruption, this means before the connection that is terminated to last base station, for user terminal is set up a new connection.In these two kinds of handovers, used band does not change.
Cellular radio system generally includes a vocoder, signal is carried out source code and signal transmission rate is fitted to transmission network, for example public telephone switching network (PSTN).Vocoder can be arranged in for example TRAU (encoder/rate adapter unit), and the latter can be positioned at for example base station controller or mobile services switching centre.TRAU generates trau frame and sends it to the base station.The coding of signal has for example reduced the signal data rate to the transmission line of base station.Vocoder and base station be receiving and transmitting signal each other, and this signal is made up of the packet that forms trau frame.
In soft handover, user terminal while and a plurality of base station communications.In soft handover, user terminal sends a signal that comprises identical information to the base station, and this signal is forwarded to vocoder.In addition, user terminal receives the signal that comprises identical information from a plurality of base stations, and these base stations have received these signals from this vocoder.
In cellular radio system, the signal Route Selection from the vocoder to the different base station alters a great deal, and the length of transmission path can be very big between vocoder and the base station.Especially the length of transmission path has caused the time delay of the signal that transmits between vocoder and the base station, thereby the base station signal that receives vocoder constantly and sent in difference.The time elongatedness the degree that alters a great deal on depend on used signal Route Selection.During the soft handover, especially send under the situation of signal to subscriber board simultaneously in a plurality of base stations, this time postpone a meeting or conference and cause a plurality of problems.
The objective of the invention is to realize a kind of soft handover, although make that time delay appears in wireless system, a plurality of base stations still can send signal to user terminal simultaneously during handover.
This is by realizing according to transmission method of the present invention of using in the cellular radio system, aforementioned cellular radio system comprises a plurality of base stations and at least one vocoder, wherein between base station and vocoder, transmit the signal of forming by packet, a plurality of base stations are basic to send signal to vocoder simultaneously, wherein vocoder receives the signal that sends substantially simultaneously in the different times of reception, this method comprises the step of the delay inequality between the different times of reception of measuring the vocoder received signal, and if desired, delay need send to signal of base station, the step of the signal that makes the base station to receive vocoder substantially simultaneously to be sent.
The invention still further relates to a kind of cellular radio system that comprises a plurality of base stations and at least one vocoder, in this cellular radio system, base station and vocoder send signal each other, a plurality of base stations are basic to send signal to vocoder simultaneously, vocoder receives the signal that sends substantially simultaneously in this system in the different times of reception, this cellular radio system comprises the measurement mechanism of the delay inequality between the different times of reception of measuring the vocoder received signal, and if desired, delay need send to signal of base station, the time-delay mechanism of the signal that makes the base station to receive vocoder substantially simultaneously to be sent.
Particularly have a plurality of advantages when the soft handover according to the solution of the present invention.This scheme comprises the delay inequality of measuring received signal, need to postpone the signal of transmission based on this delay inequality.In according to the solution of the present invention, the distance between vocoder and the base station is unimportant to the present invention.The signal that vocoder received is divided into different frames.Can detect different frames according to the frame number that provides in the frame.Frame number makes it possible to distinguish signal.Signal also can postpone suitable time delay.Suitably the signal that postpones arrives the base station simultaneously, and the latter is transmitted to user terminal simultaneously with these signals.Signal according to the branch framing of using in the solution of the present invention has formed superframe, and the feasible tolerance to the signal lag difference of the increase of frame length is increased.
Example below in conjunction with accompanying drawing is described the present invention in detail, in the accompanying drawings
Fig. 1 shows the cellular radio system of employing according to the inventive method;
Fig. 2 shows user terminal moving in cellular radio system during the handover;
The block diagram of Fig. 3 describes the structure according to cellular radio system of the present invention in detail, and
Fig. 4 summarily shows the timing of signal time delay.
Fig. 1 shows the cellular radio system of employing according to the inventive method.Can be applied to spread spectrum system according to the solution of the present invention, cdma system especially, but the present invention is not limited to aforementioned system.This cellular radio system comprises a plurality of user terminals 10,20, base station 100,200,300, base station controller 500 and mobile services switching centre 600.The function of base station controller 500 is control base stations 100,200,300.This cellular radio system also comprises the vocoder 400 that serves as speech coder.With regard to speech coding, vocoder 400 can be realized according to known technique.User terminal 10,20 is actually for example mobile phone shown in this figure.
Mobile services switching centre 600 is connected to base station controller 500 by transmission link 550.Base station controller 500 is connected to vocoder 400 by transmission link 450.Vocoder 400 is communicated by letter with base station 100 by transmission link 150, communicates by letter with base station 200 by transmission link 250, communicates by letter with base station 300 by transmission link 350.Transmission link 150,250,350,450 and 550 for example realize by the PCM technology.These transmission links also can for example be realized by Radio Link.In scheme shown in this figure, vocoder 400 is positioned at base station controller 500 and base station 100,200, between 300.But vocoder 400 also can be positioned at certain other parts of cellular radio system, for example is arranged in base station controller 500 or mobile services switching centre 600. User terminal 10,20 comprises antenna 11 shown in this figure.Base station 100,200,300 comprise antenna 101.Antenna 11,101 is worked in the transceiver antenna mode.
Fig. 2 shows user terminal 10 moving in cellular radio system during the handover.The figure shows the area of coverage 110,220,330 that each base station 100,200,300 has oneself.User terminal 10 at first moves in the area of coverage 110 of base station 100.If user terminal 10 is established to the connection of certain other user terminal 20, then user terminal 10 sends a signal to base station 100.Signal is sent to vocoder 400 by transmission link 150, and from vocoder 400 further along according to known technique propagated to other user terminal 20.Signal is called as in the other direction by base station 100,200,300 propagation to vocoder 400 from user terminal 10.
If user terminal 10 foundation are connected with the user terminal 20 that is arranged in base station 200 areas of coverage 220, then signal edge propagated according to known technique is to for example base station controller 500.This signal propagates into vocoder 400 from base station controller 500.Vocoder 400 sends signal by transmission link 250 to base station 200.Base station 200 sends to user terminal 20 by wireless path with the signal that receives.Signal from vocoder 400 to the base station 100,200,300, and further from the base station to the user terminal 10,20 propagation be called as forward direction.According to the structure of cellular radio system, signal is in the different network elements of system, and for example the base station 100,200,300, and 500 of vocoder 400 and base station controllers will be delayed when propagating.Base station 100,200,300 also cause time delay when handling this signal.But can suppose, base station 100,200, the length of 300 processing delay that caused is equal substantially.Can also suppose, be in all base stations 100,200,300 of user terminal 10 communication, base station 100,200,300 and user terminal 10 between air interface on the time delay that occurs equal substantially.
Suppose that user terminal 10 is established to the connection of other user terminal 20.100 areas of coverage 110 move to base station 200 areas of coverage 220 to user terminal 10 from the base station in mode shown in Figure 2 during this connection.If the transfer from an area of coverage to another area of coverage takes place, then cellular radio system adopts soft handover, and the connection that makes user terminal 10 be set up can not be cut off or disturb.During soft handover, user terminal 10 is communicated by letter with base station 100,200 simultaneously, and base station 100,200 sends the reverse signal that comprises identical data to vocoder 400.Vocoder 400 also sends a forward signal that comprises identical information to each base station 100,200.Afterwards, base station 100,200 sends the signal that they receive to user terminal 10.
The block diagram of Fig. 3 describes the structure according to cellular radio system of the present invention in detail.In vocoder 400 and base station 100,200, the time delay that occurs in the signal that transmits between 300 particularly can cause problem during handover.Comprise measurement mechanism 410 (MES) according to cellular radio system of the present invention, in order to the delay inequality between the time of reception of measuring vocoder 400 received signals.This delay inequality began to measure from the moment that these signals that comprise identical data arrive vocoders 400.Signal is in vocoder 400 and base station 100,200, and the delay inequality on the transmission link 150,250,350 between 300 is at most half of reverse and forward direction superframe length basically.But, if desired, can increase the length of superframe, thereby increase the delay inequality that allows.
This cellular radio system also comprises time-delay mechanism 420 (DELAY).Time-delay mechanism 420 postpones the signal that vocoder 400 sends to base station 100,200,300 when needed.Because time delay, base station 100,200,300 receive the signal that vocoder 400 is sent substantially simultaneously, although signal time delay may occur in transmitting.Time-delay mechanism 420 postpones this signal according to measurement mechanism 410 performed latency measurements.Base station 100,200,300 are received, and the delay inequality that comprises the signal of identical data equals to constitute the length of the packet of this signal basically at most.The length of packet generally equals 20 milliseconds cycle.
Suppose that during handover user terminal 10 sends signal to base station 100,200,300.Base station 100,200,300 received signals also are forwarded to vocoder 400 with it.Base station 100,200,300 send to vocoder 400 with this signal substantially simultaneously.Because these signals are to the Route Selection difference of vocoder 400, these signals have the time delay of different length.Suppose that simultaneously the signal of propagating along transmission link 250 arrives the signal that the time ratio of vocoder 400 propagates along transmission link 350 and wants fast 1 microsecond.Measurement mechanism 410 is measured the signal that base stations 200,300 are sent, and obtains aforementioned 1 microsecond with the form of signal lag difference.The delay inequality data that measurement mechanism 410 records on opposite direction are sent to time-delay mechanism 420, and the latter postpones to send at forward direction upper edge transmission link 250 signal of user terminal 10.Because time delay, the signal that vocoder 400 is sent arrives base station 100,200,300 substantially simultaneously, and these packets afterwards send to user terminal 10 substantially simultaneously.
This cellular radio system also comprises checkout gear 430 (DET), in order to detect and to identify the packet that sends from different base stations 100,200,300 from the signal that sound sign indicating number 400 is received.Checkout gear 430 detects and discerns different packets according to frame number.The detection and Identification that time-delay mechanism 420 is carried out according to checkout gear 430, deferred frame is numbered the identical packet of frame that is received with vocoder 400.If the signal that vocoder 400 received and sent comprises identical frame number, then frame number corresponds to each other.The measurement mechanism 410 that this cellular radio system is included, time-delay mechanism 420, and checkout gear 430 preferably is arranged in the TRAU that serves as vocoder.In Fig. 3, measurement mechanism 410, time-delay mechanism 420, and checkout gear 430 is positioned at vocoder and base station 100,200, between 300.But aforementioned means 410,420,430 also can be arranged in other parts of cellular radio system.
Fig. 4 summarily shows the timing of the signal time delay of being made up of packet.Or rather, the figure shows three base stations 100,200,300 and vocoder 400 signal time delay on opposite direction and forward direction.In the figure, base station 100,200,300 send a signal to vocoder 400 at identical moment T0 substantially.During 100,200,300 proceed-to-send signals, the time begins passage in the base station in supposition among this figure.The measuring-signal delay inequality time of reception of the signal that measurement mechanism 410 is received based on vocoder 400.Vocoder 400 at first receives the signal that base station 100 is sent when moment T1=40 millisecond.The signal that base station 100 sends arrives vocoder 400 after 40 milliseconds.When moment T3=80 millisecond, vocoder 400 receives the signal that base station 200 is sent.In addition, when moment T2=60 millisecond, vocoder 400 receives the signal that base station 300 is sent.Base station 100,200,300 send these signals in by the frame of 0 to 3 indication.In example shown in this figure, base station 100,200,300 is that 0 frame begins transmission from frame number.
In the whole signals that sent in three base stations 100,200,300, last arrives vocoder 400 signal that base station 200 is sent.This means that the time delay that exists between base station 200 and the vocoder 400 will be grown than the time delay on base station 100,300 and 400 routes of vocoder.Begin inhibit signal the time of reception of the signal that time-delay mechanism 420 in the end arrives after the T3.Say more accurately, postpone beginning and moment T3 moment Δ T afterwards.Time-delay mechanism 420 inhibit signal on forward direction.The latency measurement inhibit signal that time-delay mechanism 420 carries out on opposite direction according to measurement mechanism 410.Moment Δ T after receiving last frame, the frame that vocoder 400 sends with frame number 0 indication to base station 200.This means the frame that at first sends with frame number 0 indication to base station 200 at moment T4=Δ T+T3.In scheme shown in this figure, the Δ T weak point of comparing with for example frame length constantly.
The frame that vocoder 400 then sends with frame number 0 indication to base station 300.Transmission occurs in T5=Δ T+T3+ (T3-T2) constantly.Therefore, send behind the frame that sends to base station 300 20 milliseconds after sending to base station 200.The frame that vocoder 400 sends with frame number 0 indication to base station 100 at last.Transmission occurs in T6=Δ T+T3+ (T2-T1) constantly.Occur in after the transmission of base station 200 40 milliseconds to the transmission of base station 100.In according to the solution of the present invention, the signal processing operations that vocoder 400 carries out on opposite direction and forward direction is nonsynchronous.In addition, vocoder 400 does not need and base station 100,200, and 300 is synchronous.In according to the solution of the present invention, the overall delay of signal is unimportant, does not need to measure.And the signal lag difference is extremely important.Suitably postponed packet after the transmission of base station at vocoder, these packets arrive base station 100,200,300 simultaneously.In scheme shown in Figure 4, base station 100,200,300 receive vocoders 400 signal of sending of homogeneous not on essentially identical moment T7.During handover, the signal that arrives base station 100,200,300 simultaneously is easy to facilitate these signals also to send to user terminal 10 simultaneously.The length of change time Δ T can make the forward direction time delay of base station as much as possible little.In other words, change the length of cycle Δ T, can adjust forward signal, make moment that signal arrives base station 100,200,300 as far as possible constantly near the synchronized transmission of base station 100,200,300 air interfaces.The length of time-delay mechanism 420 adjustment cycle Δ T is comparatively favourable.
Although example has below in conjunction with the accompanying drawings been described the present invention, obviously the present invention is not limited thereto, in the disclosed innovative idea scope of appended claim book, can be improved in several ways.
Claims (25)
1. a kind of transmission method that uses in the cellular radio system, aforementioned cellular radio system comprises a plurality of base stations and at least one vocoder, wherein between base station and vocoder, transmit the signal of forming by packet, a plurality of base stations are basic to send signal to vocoder simultaneously, wherein vocoder receives the signal that sends substantially simultaneously in the different times of reception, and this method may further comprise the steps
Delay inequality between the different times of reception of measurement vocoder received signal, and
If desired, delay need send to signal of base station, the signal that makes the base station to receive vocoder substantially simultaneously to be sent.
2. according to the process of claim 1 wherein based on measuring resulting delay inequality inhibit signal.
3. according to the process of claim 1 wherein the delay inequality of last signal between the time of reception that equals the signal time of reception and described signal time of delay of signal.
4. according to the process of claim 1 wherein that vocoder sends first time delayed signal after it receives moment of last signal.
5. according to the process of claim 1 wherein that sending to following signal of base station postpones at most: this signal of base station is at first received by vocoder.
6. according to the process of claim 1 wherein that sending to following signal of base station postpones minimum: this signal of base station is received by vocoder at last.
7. according to the method for claim 1, this method is used the signal that divides framing, and this frame has a numbering, can detect and identify the signal with same frame number based on this numbering from the signal that vocoder received.
8. according to the method for claim 7, wherein postpone from the signal of vocoder transmission based on detection and Identification.
9. according to the method for claim 1, this method is used the signal that divides framing, in order to form the superframe of being made up of a plurality of frames.
10. according to the method for claim 9, wherein the length of superframe is a times of delay inequality of the unlike signal that vocoder received at least.
11. according to the method for claim 1, this method is used for during the soft handover of cellular radio system, this system comprises simultaneously at least one user terminal with a plurality of base station communications.
12. can adjust the delivery time of vocoder according to the process of claim 1 wherein, make these signals arrive the base station constantly at the synchronized transmission of base station air interface substantially to base station transmit signals.
13. cellular radio system that comprises a plurality of base stations and at least one vocoder, in this cellular radio system, base station and vocoder send signal each other, a plurality of base stations are basic to send signal to vocoder simultaneously, vocoder receives the signal that sends substantially simultaneously in the different times of reception in this system, and this cellular radio system comprises
The measurement mechanism of the delay inequality between the different times of reception of measurement vocoder received signal, and
If desired, delay need send to signal of base station, the time-delay mechanism of the signal that makes the base station to receive vocoder substantially simultaneously to be sent.
14. according to the cellular radio system of claim 13, wherein based on the delay inequality inhibit signal that obtains from measurement mechanism.
15. according to the cellular radio system of claim 13, time-delay mechanism inhibit signal wherein, it postpones the time delay interval of last signal between the time of reception that difference equals the signal time of reception and described signal.
16. according to the cellular radio system of claim 13, wherein vocoder sends first time delayed signal after it receives moment of last signal.
17. according to the cellular radio system of claim 13, wherein time-delay mechanism will send to following signal of base station delay at most: this signal of base station is at first received by vocoder.
18. according to the cellular radio system of claim 13, it is minimum that wherein time-delay mechanism will send to following signal of base station delay: this signal of base station is received by vocoder at last.
19. according to the cellular radio system of claim 13, this system uses the signal that divides framing, in order to form the superframe of being made up of a plurality of frames.
20. according to the cellular radio system of claim 13, this system uses the signal that divides framing, and comprises checkout gear, in order to detect and to identify the signal with same frame number from the signal that vocoder received.
21. according to the cellular radio system of claim 20, wherein time-delay mechanism need to postpone the signal of transmission based on detection and Identification.
22. according to the cellular radio system of claim 20, wherein vocoder generates a superframe according to the signal of minute framing, the delay inequality of vocoder received signal is at most half of length of this superframe.
23. according to the cellular radio system of claim 13, wherein signal is made up of packet, the delay inequality of different base station received signal is at most a times of data packet length.
24. according to the cellular radio system of claim 13, this system comprises during the soft handover simultaneously at least one user terminal with a plurality of base station communications.
25. according to the cellular radio system of claim 13, wherein time-delay mechanism is adjusted the delivery time of vocoder to base station transmit signals, makes these signals arrive the base station constantly at the synchronized transmission of base station air interface substantially.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 97181185 CN1242919A (en) | 1996-12-30 | 1997-12-19 | Simulcast handoff method compensating for cable length differences |
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| Application Number | Priority Date | Filing Date | Title |
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| US08/774,780 | 1996-12-30 | ||
| CN 97181185 CN1242919A (en) | 1996-12-30 | 1997-12-19 | Simulcast handoff method compensating for cable length differences |
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| CN1242919A true CN1242919A (en) | 2000-01-26 |
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| CN 97181185 Pending CN1242919A (en) | 1996-12-30 | 1997-12-19 | Simulcast handoff method compensating for cable length differences |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105795428A (en) * | 2016-03-14 | 2016-07-27 | 四川道泉老坛酸菜股份有限公司 | Preparation method of seasoning of boiled fish with pickled leaf mustards and peppers |
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1997
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105795428A (en) * | 2016-03-14 | 2016-07-27 | 四川道泉老坛酸菜股份有限公司 | Preparation method of seasoning of boiled fish with pickled leaf mustards and peppers |
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