CN101159481A - Method and apparatus for synchronizing base stations - Google Patents

Abstract

Method and apparatus for synchronizing base stations employing an independent synchronizing source or identifying a base station as a master source. An RNC (C-RNC) or a base station may designate one base station or a UE to acquire measurements derived from base stations to achieve synchronization. Synchronization activities may be regularly scheduled or may be undertaken when periodic measurements indicate that a drift value exceeds a given threshold.

Description

Method and device with base station synchronizationization

Patent application of the present invention is that international application no is PCT/US03/03351, international filing date is on February 4th, 2003, the application number that enters the China national stage is 03803296.1, and name is called the dividing an application of application for a patent for invention of " with the method and the device of base station synchronizationization ".

Technical field

The present invention relates generally to digital communication system, especially, the present invention is about one of a plurality of base stations of synchronization in sub-district formula communication system system and method.

Background technology

3 of proposition ^RdIn generation,, (3G) wireless communication protocol need be based on simple, still need be with each base station external sync in the method for the expensive program of a pinpoint accuracy external source.It supports passive the listening attentively to from it on a channel in Technology Need base station of base station synchronizationization, for example the neighbours' of a synchronization channel (SCH) or a common control physical channel (CCPCH) synchronization transmits, and adopts those programs carried out for synchronization by subscriber equipment (UE) that are similar to.The one or more neighbours that other method needs each base station basis to be used to transmit listen attentively to and transmit a certain synchronization burst once in a while.Another method has the time of advent difference (TDOA) of UEs measurement from the transmission of each sub-district of two sub-districts.These technology are utilized the correct accurately source in each base station.Because each base station has this source, these technology are expensive and not convenient.

Therefore, existence is used for its permission not consuming the quick, effective of extra physics source arbitrarily between the base station, reaches the more not demand of expensive synchronized system and method.

Also there is the interruption of the minimum number be used to use normal service,, provides the demand of precise synchronization system as the message flow that reduces between Node B and radio network controller (RNC).

Summary of the invention

A kind ofly be used to utilize independent synchronization source, or discern method and the device of a base station as a dominant base synchronization base station, a RNC (C-RNC) or a base station can specify a base station or a UE to require measurement from the base station to finish synchronization.Can regularly sort or surpass one givenly when critical at periodic measurement indication one drift numerical value, can agree the synchronization activity.The aforementioned method that is used for base station synchronizationization comprises step at least: a) detecting a plurality of asynchronous base stations at least one of them; A1) decision is according to having than this at least one asynchronous base station base station of time quality synchronization quality more; B) measure a plurality of sub-districts time signal that comprises by the measured sub-district time signal in this preferable time synchronized quality base station; And c) is measured as the basis with this sub-district time signal, and do not use from having and measure and one of revise in a plurality of asynchronous base stations at least than the timing signal of any base station of one of at least also poor time synchronized quality of these a plurality of asynchronous base stations.

The purpose of preferred embodiment system and method and advantage can be understood by practising after this skill person reads the detailed description of preferred embodiment.

Description of drawings

Embodiments of the invention will be referred to graphic explanation, the similar assembly among the wherein similar digitized representation figure, wherein:

Fig. 1 is the calcspar of a communication system.

Fig. 2 is the calcspar of a radio network controller (RNC) of preferred embodiment generation of the present invention.

Fig. 3 is a base station of preferred embodiment generation of the present invention and the calcspar of UE.

Fig. 4 is the explanation of class's time response design of preferred embodiment generation of the present invention.

The flow chart of the system that Fig. 5 a that obtains jointly and 5b comprise preferred embodiment of the present invention.

Embodiment

Fig. 1 illustrates that one simplifies wireless extensions spectrum cdma (CDMA) or time division duplex (TDD) communication system 18.System 18 comprise a plurality of Node B s 26,32 ... 34, a plurality of RNCs 36,38 ... 40, a plurality of subscriber equipment (UEs) 20,22,24, and a core network 46.Node B 26 in system 18 is in communication in relevant user equipment 20-24 (UE).Node B 26 have be relevant to a single base station 30 ', or a plurality of base station 30 ₁... 30 _nA single positioner (SC) 30.The known relevant geographic area of each base station services as a sub-district.Even should note disclosing base station synchronizationization, also can use the present invention to finish the sub-district synchronization.

The group of Node B s 26,32,34 is connected in a radio network controller (RNC) 36 by the Iub interface.RNCs 36...40 is connected in core network 46 by the Iub interface.Be used for understanding, only propose a Node B below, but can easily the present invention be put on a plurality of Node B s.

Having two can the synchronized basic mode of management node B---centralized approach or decentralized method.In centralized approach, all subfunctions that base is revised when carrying out cell measurement and sub-district with the demand of control RNC (CRNC) reach measurement report to RNC.In decentralized method, do not finish some or all of Node B functions from the direct instruction of RNC.The centralization that also has different angles.For example, preferred approach almost completely is centralization, but does not allow to be used for a limited standalone feature; For example as following discussion, the observation trend that Node B is revised according to the time base that transmits by RNC can independently be adjusted its internal frequency and originate.

One example of decentralized method tells each sub-district of the sub-district in Node B s 26,32,34, that sub-district to be to use in synchronization and its clock signal of the independent adjustment of clear notice of time of RNC not being changed of RNC each sub-district of allowing this sub-district then about RNC 36.In present technique the sub-district must keep a precision clock signal and, because all sub-districts are the adjustment that interdepend, cannot guarantee whole stabilities of a system.Advised this decentralized method, but it not a preferred approach.

According to a preferred technique, RNC 36 maintains in the Node B s 26,32,34 and the synchronization of the whole base stations between Node B s 26,32,34.Be referred to Fig. 2, RNC 36 comprises a database 59, one synchronous chemical control system device 55, the one message generators 53 and with a covariance matrix 57 and measures receiver 54.RNC 36 can require from a base station 30 by its message generator 53 ₁... 30 _nOr UE20,22,24 measurement; Measurement receiver 54 by it receives measurement; The best synchronization controller 55 that uses upgrades its assessment according to these evaluation status; And one group of state that is stored in the covariance matrix 57 of management.Storing state is to use in synchronization and represents each base station 30 to be relevant to the time error of a reference, the speed of the change of each time error and in the base station 30 ₁... 30 _nBetween propagation delay.

RNC 36 also manages one group of measurement that is stored in the database 59, and it comprises: the time of advent of a measured waveform (being burst isochronous); As the TDOA that measures by a UE 20 from the transmission of two base stations; And the assessment of state uncertainty and measuring uncertainty.Database 59 further comprises the assessment that is used for all important states, for example be used for except that main frame all sub-districts (Node B), time bias or error (at nanosecond, or in the microsecond, usually numerical value in+/-3 microseconds in+/-3000 nanoseconds scope); The time speed of the change of time bias, for example drift of the drift of per second nanosecond or per second microsecond.State vector is the configuration group of all states, for example (Δ t (1), Δ t (2) ..., Δ t (n-1), $\frac{d}{\mathrm{dt}}\left(\mathrm{\Δt}\left(1\right)\right),$ $\frac{d}{\mathrm{dt}}\left(\mathrm{\Δt}\left(2\right)\right),...,$ $\frac{d}{\mathrm{dt}}\left(\mathrm{\Δt}(n-1)\right)$ ), wherein have n Node B s, comprise main frame, Node B (0) indicates state vector X=x (1), x (2) ... x (m) is wherein

m＝2(n-1)＝Δt(1)， $\frac{d}{\mathrm{dt}}\left(\mathrm{\Δt}\left(1\right)\right),$ Δt(2)， $\frac{d}{\mathrm{dt}}\left(\mathrm{\Δt}\left(2\right)\right),...,$ Δt(n-1)， $\frac{d}{\mathrm{dt}}\left(\mathrm{\Δt}(n-1)\right),$ Covariance matrix is m * m matrix, wherein R (I, J)=E (result's of (x (i) x (j))=i and j assembly expected value.RNC 36 uses the advanced person to filter, and for example Kalman filter to assess the parameter of the relevant clock signal drift of its definition, reaches for example accurate scope between an assembly and another assembly of distillation parameter.Evaluation time drift be to use in the frequency of reasoning between the frequency reference between indivedual base stations do not match and legitimate check with guarantee once in a while, coarse inaccuracy measures Rogue program.Kalman filter is also assessed the uncertainty of different conditions.These numerical value are to be stored in the covariance matrix.The diagonal assembly that should note covariance matrix is represented the change of each individual states.

A stage program is used in preferred embodiment, and wherein RNC 36 configurations one time quality is to each base station 30 ₁... 30 _n RNC 36 is by selecting a base station as being used for time basic this time of reference measure quality of all other base stations.It is a variable time quality of upgrading according to the correction of measuring and applying to dispose all other base stations.The time quality can be an integer (for example 0 to 10).One more low-quality numerical value comprises a preferable accuracy.As a conversion, quality numerical value can be continuous (floating-point) variable.The quality numerical value of advantageous configurations reference base station (dominant base) 1.Dispose all and remain its numerical value that is relevant to the reference base station change and adjusts of other base station.For the quality diagonal design of this time is described, Fig. 4 shows a dominant base, and (from 1, from 2, from 3) it is relevant to the time quality numerical value that dominant base changes from the base station wherein to dispose all.In one embodiment, it is relevant to the numerical value that changes from 1 base station from the time quality of 2 base stations in configuration, and configuration it is relevant to the numerical value that changes from 2 base stations from 3 base stations.

Conversion embodiment to a complete master/slave structure of diagonal is a pairing structure, needs each right base station to hear and moves the frequency of its peculiar frequency near other base station mutually.Place by an assembly each base station single weight definition adjustment correlated measure and be stored in RNC database 59.The program of adjusting each base station be identical as the preferred embodiment that proposes in the above in disclose, remove weight adjustment " synchronously " that basis is disposed at indivedual base stations and reach " asynchronous " base station the two.Utilize different weights, the change angle at center can be finished in a base station, arrives fully between the dispersion at complete center.Yet in many environment, the pairing clock signal update of this type cannot guarantee that this drifts about from other continuous clock signal to the base station to the base station.

In true stage clock signal structure, RNC 36, in the normal mode of operation, upgrade the state that covariance matrix 57 is used for being stored in RNC database 59, each scheduled time unit once, (for example every five seconds or by by time of operator one decision once).The diagonal assembly of covariance matrix 57 is that the assessment of each base station time error of being relevant to dominant base changes.

Time error in a base station changes when surpassing a predetermined critical, and RNC 36 initial messages are upgraded with the time error of supporting the base station.Carry out renewal according to the mode in three modes: the first, indication purpose base station measurement is from a neighbor base station 30 ₁, 30 ₂... 30 _nOne of time (BSTOA) of arrival one base station of burst isochronous; The second, indication has a neighbor base station 30 of better quality ₁, 30 ₂... 30 _nMeasure the BSTOA of the transmission of purpose base station; Or the three, one UE 20 that base station of measurement and neighbor base stations 30 ₁, 30 ₂... 30 _nThe BSTOA of burst isochronous.

In first and second method, use the base station to base station BS TOA, observe the time of advent that the transmission of another base station is arrived in a base station.Be referred to Fig. 3, one transmits base station 30 ₁Transmit a known transmission type in a scheduled time.This transmission type can be from base station 30 ₁A synchronous burst of burst isochronous generator 62, its by the preceding transmission of an antenna 70 radiation by an isolator 64.Receive base station 20 ₁Detecting transmits waveform, transmits it and arrives measurement mechanism 68 by an isolator 66, at received signal unanimity output one big numerical value when transmitting the expection mark of output then.If receive and transmit base station the 20, the 30th, in same position and have the accurate synchronization clock signal, the output of measurement mechanism 68 will as identical time of transmitting waveform produce.Yet clock signal imbalance and transfer path postpone to produce a time difference.

The definition transfer path postpones as every equation 1:

R/c+x equation 1

Wherein R/c is a distance R of cutting apart c between a delivery unit and receiving element by the light velocity.Item time x metering is used for device and postpones.When being very remote in the base station, amount R/c disposes usually.Radio wave transmits with the light velocity, near 1 foot every nanosecond, or per second 3 * 10 ⁸Meter.The purpose of base station synchronizationization is that configurating base station is in the 1-3 microsecond.Therefore, be when cutting apart in the base station according to the distance of 1/2 mile (1km) or more ordering, these distances have a relevant important effect that postpones.Yet, be used for being compared to the measurement precision of configuration by ten meters million minutes of cutting apart or Microcell, x, distance is inessential.

Consider according to these, attempt synchronization away from base station (more than 1km) time, the understanding that separates the sum of (promptly apart from) is important.Attempting synchronization greatly during the base station in 50 meters, the tram is inessential.After the measurement of carrying out BSTOA, configuration is stored in known transmitting range and the imbalance difference in the time of consideration between the base station in the RNC database 59.

The 3rd method measured the relevant difference time of advent (TDOA) between two transmission that transmit by two different base stations as observing by a UE 20.UE 20 measures and is reported in from the observation TDOA between the transmission of two base stations.RNC 36 transmit a message to UE 20 to measure the TDOA of two base stations.According to the reception of this message, UE 20 receives the transmission of two base stations by its antenna 72 and isolator 66, and uses UE to measure receiving system 68 and measure TDOA, and isolator 66 and antenna 72 transmit and measure its relevant base station.

If the UE position is known (is it to each base station of two base stations be known apart from r1 and r2), and the two timing of base station is correct, and TDOA is, as every equation 2:

(r1-r2)/c equation 2

One indicating device of base imbalance in the time of from the measure error of this numerical value will being.Practise in this skill person as those and to understand, if be obviously little as to be used for million fens size sub-districts will be true, with the unnecessary numerical value of knowing them apart from r1 and r2.Observe the measurement of TDOA with directly using as the time difference of transmission.

In case select a method, transmit suitable message and arrive or a base station 30 ₁... 30 _nAn or UE 22,24,20.If message is sent to base station 30 ₁... 30 _n, for example the base station 30 ₂, tell base station 30 ₂Monitor and measure that neighbours.If message is sent to a UE 22, UE 22 is in that other base station of its peculiar base station external pelivimetry in indication.

Get back to reference to figure 2, in case RNC 36 has been stored in base station 30 in its database 59 ₁... 30 _nBetween distance, have it and have preferable if it is checked in regular turn to understand in the base station of upgrading 30 ₂A neighbor base station 30 of a time quality ₁In case find this a kind of neighbor base station 30 ₁, an initial message is to neighbor base station 30 ₁To obtain from " asynchronous " base station 30 ₂One measure.In addition, RNC 36 can transmit a message to " asynchronous " base station 30 ₂, and requirement obtains neighbor base station 30 ₁One measure.The purpose that is used for present embodiment, the base station of requirement, " asynchronous " base station 30 ₂, obtain " synchronously " base station 30 then ₁One measure and transmit and measure numerical value and get back to RNC and measure receiver 54.RNC measures receiver 54 forward directions and measures numerical value to synchronization controller 55, and it is by deducting the time that delivery time r/c calculates the transmission of measuring.

In case calculate the time of transmitting by RNC synchronization controller 55, numerical value is to be compared to the numerical value that is stored in the RNC database 59.RNC synchronization controller 55 computer card Thalmann filters gain then, and use calculate and specified time of arrival between difference and common gain be updated in state in the covariance matrix 57.If difference be surpass one clear and definite critical, under the control of RNC 36, obtaining " synchronously " in other base station 30 ₃... 30 _n, then RNC message generator 53 will transmit another message to " asynchronous " base station 30 ₂To adjust its time basic or its reference frequency.Note following two problems:

(1) in a preferred embodiment, RNC can transmit a message to Node B to adjust its frequency; Yet, its can be (planning in third generation cooperation in this way, (3GPP) in the state of RAN explanation) this a kind of can non-existent message, and therefore cannot use this characteristic.

(2) in this idea, be not used in the demand of new measurement, the evaluation time error can surpass a critical and triggering base correction for the moment, promptly utilize the high reliability assessment of drift speed, RNC is simply by using drift speed to infer that it is the permission time bias that surpasses it that time error can correctly be discerned a Node B.

Base station 30 ₂Adopt the adjustment that requires and repay it to RNC measurement receiver 54.Be updated in the database in the RNC36, comprise purpose base station 30 ₂The change of correction, its time speed of time reference (if do not had a frequency adjustment, it is to apply), the renewal of its covariance matrix 57 (comprises, be even more important its assessment RMS time error and drift error), reach renewal to its time quality.

Be referred to Fig. 4, never the configuration at that time base be according to another base station relatively the correction the base station its equal or preferable in one its be the quality of follower's base station.This program guarantees stability.For explanation,, can only dispose from 2 base stations it and be inferior to from a numerical value of the numerical value of the time quality of 1 base station if revise one from 2 base stations.This time quality of guaranteeing a base station with asynchronous in identical time quality level or less time quality level from the base station, it will cause one group of base station drift " asynchronous " in dominant base at last.

As disclosing, be used to adjustment " asynchronous " base station 30 in the above ₂The transform method of obtaining measurement uses a UE 20,22,24.If select this method, a message is sent to UE 22 to measure " asynchronous " base station 30 by RNC 36 ₂And " synchronously " base station 30 ₁Burst isochronous.In case obtain measurement by UE 22, measurement be sent to RNC 36 and processing.Be similar to method described above, compare and measure the known measurement in being stored in RNC database 56 and covariance matrix 57, and an adjustment measurement is sent to " asynchronous " base station 30 ₂

Explanation is according to a flow chart of a method of preferred embodiment in Fig. 5 a and 5b.36 every unit times of RNC are upgraded covariance matrix 57 and database 59 once (step 501).In RNC 36 detectings one base station 30 ₂... 30 _nTime error when change surpassing a predetermined critical (step 502), be that the time error of upgrading " asynchronous " base station changes, whether RNC 36 decisions use a base station (BS) to measure BSTOA or a UE measures TDOA (step 503).If BSTOA are measured in RNC 36 decision, or the neighbor base station that message is sent to " asynchronous " base station to be measuring the time (BSTOA) that arrives the base station, or message is sent to the time of advent (step 504) of " asynchronous " base station with the measure neighbor base station.Suitably the base station is obtained the measurement (step 505) of requirement and is transmitted and measures RNC 36 (step 506).

If TDOA is measured in RNC 36 decisions, RNC 36 transmits a message to the TDOA (step 507a) of a UE to measure two base stations, and one of them is " asynchronous " base station.UE measures the TDOA (step 507b) of each base station, and transmission measures RNC 36 (step 507c).

According to the reception (step 508) by the RNC 36 that suitably measures, RNC 36 compares and measures the numerical value (step 509) in being stored in RNC database 59.If difference be surpass one clear and definite critical, RNC36 according to this difference transmit a message to " asynchronous " base station to adjust base or its reference frequency (step 510) at that time." asynchronous " base station produces the adjustment (step 511) that requires and repays it to RNC 36 (step 512).Upgrade RNC database 59 and covariance matrix 57 then to include new numerical value (step 513) in.

One preferred embodiment is its system and method that belongs to each RNC 36.Formerly in the skill, control radio network controller (C-RNC) direct communication is in its base station, and service radio network controller (S-RNC) direct communication is in its UE.Be used for neighbor base station wherein and be the state under different RNCs s control, can have the demand that between the C-RNCs of its control neighbor base station and UEs and S-RNCs, increases communication.

Replace its structure according to chemical control system in the complete set, a conversion embodiment can more disperse more new construction according to one.In the present embodiment, each member of a pair of base station that can listen attentively to mutually can move its peculiar frequency to approach the peculiar frequency of other member.By one group its be to be disposed at each base station and to be stored in the relevant sum that the single weight definition in the RNC database 59 is adjusted.The program of adjusting each base station is identical as disclose in the preferred embodiment in front, removes weight adjustment " synchronously " that basis is disposed at each base station and reaches " asynchronous " base station the two.Utilize different weights, the change angle at center can be finished in a base station, arrives fully between the dispersion at complete center.

Or centralization or decentralized method in, a plurality of sub-districts that wherein remain in the single node B are that " synchronously " has many possibilities.Most preferred embodiment activation 36 delivery times of one RNC are revised and/or frequency is adapted to a base station 30 ₁... 30 _nDominant base is can respond to guarantee that each base station in its base station in a single node B has from it, accurately the time reference in a specific limited.RNC 36 is according to its algorithm and correction, supposes to have a negligible error and is present between dominant base and the base station thereof and therefore and supposes that all base stations have identical time reference.

Therefore, RNC 36 does not attempt to be evaluated at dominant base and from the indivedual time errors between the base station, reaches because relevant RNC 36 does not carry out a correction, and the time error between each base station of dominant base and other base station must be eliminated or compensate to dominant base.Present embodiment appears at the sharp interface between a RNC 36 and the dominant base.Its activation dominant base applies its peculiar solution to obey the synchronization that it will be applicable to million fens base stations.It is necessary aerial synchronized sum that this method also reduces it, because only need to measure a sub-district of a Node B is used for all sub-districts in Node B with understanding present time and frequency reference.Yet, this is the big result in the hardware of Node B, because necessary transmission clock signal reference between Node B positioner (SC) and sub-district, if the distance that reaches between a SC and a sub-district is big, only the time error according to distance produces this shortcoming.

In the first conversion embodiment that is called " sub-district basic frequency and time reference ", each base station has an independent time and frequency reference, and its activation one RNC 36 revises with the delivery time and/or frequency is adapted to each base station.RNC 36 assesses it and represents the time of each base station and the state of frequency error according to its algorithm and correction.Therefore, RNC 36 attempts to be evaluated at the indivedual time errors between each base station and the dominant base, does not offer help to assess the state of another base station about the measurement of a base station.Therefore, base station manufacturer only needs to be provided at the time of base station and the scattered limited error in the frequency drift, and each base station must have aloft and one can accept connection to another base station (identical or different base station).

This conversion embodiment helps wherein, and the distance between the base station is remote formula zone, big sub-district.By the measurement about another base station of submitting to same node point B, it is limited revising the ability that a base station submits to the time reference of a Node B.

In the second conversion embodiment that is called " SC basic frequency reference/sub-district master's time reference ", the independent time reference is used in each base station, but dominant base provides a frequency reference.One RNC 36 transmits the time correction and/or the single-frequency that are used for each base station individually and is adapted to a dominant base.RNC 36 guarantees that the clock signal of each base station is the clock signal that submits to dominant base aspect frequency.RNC 36 is according to its algorithm and correction, suppose to have dominant base and configurating base station between negligible error, but its compensation as constant is treated in assessment.RNC 36 be evaluated at dominant base and the base station between time error, and belong to the common frequency drift of the base station of dominant base.

One the 3rd conversion embodiment has those characteristics that are similar to " SC basic frequency and time reference " embodiment, but wherein the base station is to help away from dominant base.The device that present embodiment provides removal to lack of proper care in the time aspect remote.Utilizing these time biass is advantages of stable hypothesis, and the present embodiment utilization submits to the advantage of measurement of frequency of the clock signal of dominant base about any base station, upgrades to be used for the drift speed that all submit to the base station of identical dominant base.

In being called the 4th conversion embodiment of " auxiliary SC basic frequency and clock signal with reference to ", RNC36 assessment is provided and dominant base to support its synchronization that submits to its base station.One RNC, 36 transmission are used for the time correction of each relevant base station and/or indivedual dominant bases that frequency is adapted to it.Dominant base guarantees that each base station in its relevant base station has and submits to itself, accurately the time reference in a specific limited.Dominant base can select to use the assessment of single base station to help base station synchronizationization.RNC36 is according to its algorithm and correction, is based upon the time between dominant base and the base station thereof and the best-evaluated of frequency error.Aspect the executing state assessment, assess the relevant assurance of its weight between measurement and base station error uncertainty.Therefore, RNC 36 attempt to be evaluated at dominant base and the base station between indivedual time errors, and dominant base assessment and/or compensation be at dominant base and obey time error between its each base station of time reference, or require the help from RNC 36.Present embodiment allows to be used for the structure of similar " SC basic frequency and time reference " embodiment, but allows to be used for coming the adjustment than the low accuracy transmission of autonomous reference, discharges some restrictions of that embodiment.

In all timing models, use the interruption accurate synchronization network of the minimum number of normal service.This reduces the sum that hides from view in the interface aloft, and reduces the quantity of the message of walking about on the IUB interface, causes the minimizing as the sum of the gauge outfit of top explanation support node B synchronization needs.

In high chip rate (HCR) TDD and low chip rate (LCR) TDD system, need the use of blanking signal to produce the measurement that requires by RNC for being used for any Node B.HCR TDD system hides from view and helps to use a predetermined ordering and only need Node B usually, (being used for measuring by another Node B the purpose of its TOA), transmits a blanking signal so that can produce a measurement.LCR TDD system needs transmission node B, as some its adjacent cells, hides from view the interference that produces by measured node B by these adjacent cells on received signal to avoid.Practise in this skill person's understanding as those, the normal running in system is disturbed in the use of too much blanking signal in system, causes decay.

As disclosing in the above, according to Node B synchronization procedure of the present invention, (perhaps centralization or decentralized), about identical function (and subfunction):

1) produces cell measurement

A. indication transmits the sub-district transmission burst of burst.

B. tell the sub-district in the vicinity that transmits the sub-district to hide from view their down link physics synchronization channel (DwPCH) and produce a measurement.

C. report is measured if necessary.

2) sub-district that produces the timing of the one or more sub-districts of foundation is adjusted.

Should notice that equation 1 and equation 2 are can be asynchronous.Can not have a sub-district adjustment to produce a plurality of cell measurements, and can have a plurality of sub-district adjustment that are used for a single cell measurement.

In centralized approach, the identical ordering message of foundation is finished all subfunctions of cell measurement, and requires the sub-district adjustment by control RNC (C-RNC).In decentralized method, each subfunction of cell measurement separates message about one and Node B can independently be carried out sub-district adjustment program now.

If physical accidental access channel (PRACH) burst is the DwPCH that replaces in the function in the above, carry out above and equal the synchronization of HCR TDD Node B, the difference of utilization in the state of the use that upwards connects the PRACH burst, all UEs in the sub-district must understand program so that be need be used for hiding from view when synchronous upwards connecting the PRACH time slot at it.

All need these messages of the use of Iub and their flow load to can be a coefficient.

Yet message indicates its time base of a Node B correction influence Iub, but is the air-interface resource.Decentralized method utilization separates message, but does not have a program, will cause more multiple message but they are to cease than news in brief on Iub.Yet the Iub load is switched about more than the message size, so the quantity of message is the coefficient in the Iub load.

For eliminating the sum that hides from view that in system, produces, guarantee that to produce to measure sequential synchronization, the 5th conversion embodiment use the ability of RNC to follow the trail of the advantage time drift of each Node B about a definition reference from the demand that is used for Node B s.As top announcement, RNC can transmit message and measure, hides from view a transmission to Node B to produce one, and produce to its time base correction.Can be according to a preset program, for example periodicity (per hour, per second or the like ...) transmits these messages.The use of the advantage of each Node B time drift speed reduces the necessary cycle that produces measurement.If a short time drift is not a coefficient, RNC utilize one very the measurement demand of low rate can maintain synchronization in the stable state.Therefore, the speed of measuring demand will directly be drifted about about advantage is inferior.

For example, if Node B (A) has the advantage time drift speed of an X minute every day, RNC can produce Node B (A) about being used for Node B (A) the measurement demand of some time references more than the sum of the time of three microseconds of drifting about, begin time between any right sub-district in the worst error of news in the frame, for example.The sum of time is only according to long time drift speed.Therefore, the periodicity of measurement demand will equal its sum that is used for the time of Node B (A) drift 3 microseconds.

It is only necessaryly to be used for a given Node B and can to measure the TOA of the transmission of other Node B.As top explanation, can judge that the node in two Node B has more precise time base.RNC can select the node in two Node B to indicate a correction.In simplified example, the fixed time reference measure is from the TOA of another Node B (promptly from).The RNC use is measured with the time error of improving its follower and the assessment of drift.

Because time drift (stability) of weak point item is a coefficient, the speed that drives measurement by the inferior stability of weak point item is as inferior stable with respect to advantage.In fact, RNC can obtain the very accurate assessment of the advantage time drift speed of a given Node B, but drift speed can change according to past history, therefore needs new the measurement.When probabilistic growth time speed is critical above one, obtain these new measurements.This time speed numerical value of the growth of uncertain (but maximum permissible error) can be from any measurement that is stored among the RNC.The method of known this speed of decision is used the measurement that stores in skill.Frequency about the Iub modified message will be symmetrical in advantage time drift speed, but reach reverse symmetry in the maximum permissible error, and it will be higher than the frequency of aerial survety.

Being proposed to be used in present group synchronous message of Node B from RNC to the Node B comprises and is used for RNC and tells Node B to hide from view one to transmit, produce one and transmit, carry out one synchronously and measure or produce the ability that time base is revised.Propose another message that order one Node B produces the measurement of N group, obtain an average and then, report that perhaps this mean values is to RNC or produce a correction.These instructions can by one-period program or as a single incident.These new messages can help to reduce the Iub flow, but they will not reduce the demand that is used to hide from view and measure supporting.

Some other methods that reduce the Iub information rate comprise:

1) provide it to indicate a Node B to revise the new message of its bit rate clock signal by n1 ppm; N1 is a predetermined quantity.

2) provide it to indicate a Node B to revise the new message of its frequency reference (its drive clock signal) by n1 ppm.

3) provide a parameter to indicate a Node B to adjust message by the sub-district that exists that the every n2 of n1 chip interrogates its clock signal of frame increase (or minimizing) to it, the quantity of interrogating frame by increase is to repeat adjustment.

4) utilization to obtain from its drift speed from the time correction of RNC, reaches independent its clock signal of adjusting about a demand of Node B.

Method 1 and 2 requires RNC to be transmitted in to exist the sub-district to adjust the extra message that instructs node B in the message is adjusted its bit rate clock signal or the clear and definite sum of frequency speed to one.According to the advantage time drift speed of Node B, periodically the time is transmitted this message with some.For example, if the bit rate clock signal that Node B should per ten (10) microseconds be adjusted in RNC decision once, per ten (10) microseconds transmit message once, the sum that its indication is adjusted.

Method 3 requires RNC to transmit a single message and indicates to Node B how long (adjustment speed) upgrades its bit rate clock signal, and it wherein measures the inferior drift speed of the assessment advantage of calculating according to using by RNC to be stored in.Because RNC can calculate advantage time drift speed, it can not have the Iub flow to utilize a single message to adjust the advantage time drift speed of Node B s continuously, RNC must consider short time drift along only may changing of foundation advantage subrate afterwards, and it is unnecessary to repeat to produce identical correction overtime.Only transmit this message once.Node B continues to upgrade its bit rate clock signal with the adjustment speed that receives or but frequency reference has arrived the maximum permissible error up to the RNC decision, and requires to adjust from it measurement of the Node B of its assessment advantage time drift speed.

Method 3 also is the simplest and can utilizes the less additional functionality execution of timing being adjusted message.And this allows RNC to understand Node B behavior (shortcoming of decentralized method).

The selection of the management of two measurements that are used for disclosing above:

RNC assesses uncertainty (according to tracer technique) at it and surpasses one and require to measure when critical;

RNC can one measure ordering before simply ordering, suppose that one is important preferential.

First selects by the only best interference that reduces about air-interface of ordering measurement when needed, but increases the Iub flow.Second selects to reduce the Iub flow.By suitably disposing the different measuring renewal rate, can be used for difference by (historical decision) adjustment RNC according to individual nodes B drift characteristic.Any one of these two selections is to surpass an ordering of present LCR Node B candidate method about the loss of strength that air-interface and Iub require, and can utilize and exist the message group to carry out any selection.

Do not need method 3, but will provide extra minimizing according to the Iub flow.Increase by a simple modification and can finish it and be used for LCR TDD by the sub-district synchronization being adjusted message.

Method 4 remove some in RNC tracing algorithm and they are included in Node B.Node B is from obtaining its drift speed from the time correction of RNC, the drift speed that reaches according to it determines one to adjust speed.Node B is adjusted speed according to decision and is adjusted its clock signal.

Discussing when of the present invention, practise other change in this skill person will understand the scope of the invention that illustrates in the claims according to preferred embodiment.

Claims (6)

1. subscriber equipment (UE) that is used for a digital radio system with synchronization base station one of in a plurality of base stations of this system, this UE comprises:

Be used to receive the device of a demand with synchronization one base station;

Be used for obtaining the device that a BSTOA numerical value is used at least one reservation base station of the device of this base station and these a plurality of base stations, and this at least one reservation base station in these a plurality of base stations is to have a time synchronized quality better than this base station in these a plurality of base stations; And

Be used to transmit the device of this BSTOA numerical value.

2. UE as claimed in claim 1, it has makes the device of a plurality of base stations under a plurality of radio network controllers (RNCs) control.

3. UE as claimed in claim 2, it further comprises and is used for transmitting the device of this BSTOA numerical value to one of this RNCS.

4. one kind one of is used for obtaining in time of a plurality of base stations of a wireless communication system and frequency-synchronized synchronized method, and wherein a RNC transmits one and revises numerical value base station of being appointed as a dominant base in these a plurality of base stations, and it comprises:

Dispose a weight and respectively keep the base station in this reservation base station;

Dominant base transmits one and revises numerical value to a highest weighting base station; And

This highest weighting base station is transmitted one and is revised numerical value to the high weight of this time base station.

5. method as claimed in claim 4, wherein have the correction numerical value of the reservation base station reception of a weight numerical value that is lower than the high weight numerical value of this time, and transmit this correction numerical value to this base station with weight numerical value that only is lower than its weight numerical value from a base station with weight numerical value that only is higher than its weight numerical value.

6. synchronized method one of in the time of a plurality of base stations that are used for being provided at a wireless communication system and the frequency-synchronized, wherein a RNC transmits one and revises numerical value;

This dominant base transmits revises numerical value to withing a hook at the end of base station.

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