CN100393076C - Time adjusting method for wireless access network and core network interface user-plane - Google Patents

Abstract

The present invention discloses a time adjusting method of a wireless access net and a user plane of a core net interface. Firstly, a reference frame is determined by an SRNC; the frame number and the arrival time of the current received data frame are recorded; the frame number difference of the current frame and the reference frame is multiplied by the clocking interval of an Iu port; the arrival time of the reference frame is added so as to obtain the ideal arrival time of the current frame. Whether the time difference that the arrival time of the current frame subtracts the ideal arrival time is within a given range is judged. If true, time adjustment does not proceed; the reference frame is updated, and a next frame is continuously processed; else, trigger a time adjustment process between the frame and a core network. Furthermore, in order to obtain a high-accuracy reference frame, a final frame is used as a reference frame after continuous multi-frame timing is accurate. The present invention realizes an Iu UP time adjusting function defined in a protocol by a simple method; the time sequence of down link data from an Iu interface to an SRNC can be effectively controlled in order that the buffer time delay in the SRNC is minimal.

Description

The time adjusting method of wireless access network and core network interface user plane

Technical field

The present invention relates to radio network controller (RNC in the WCDMA system, Radio NetworkController) and the interface (being defined as the Iu mouth) of core net (CN:Core Network), be particularly related to the method for adjustment of the user plane time of this interface service radio network controller (SRNC:Sever Radio Network Controller, there is professional RNC in expression) side.

Background technology

In the WCDMA system, the Iu mouth is the standard interface that connects between RNC and the CN, and Iu mouth user plane (Iu UP, Iu User Plane) is the user data transmission agreement of Iu mouth, is mainly used in the transmission that realizes user data between CN and the RNC.Iu mouth user plane has two kinds of operator schemes: transparent mode (TrM:Transparent Mode) and Service Data Unit (SDU:Service Data Unit) size carried out predefined support mode (SMpSDU:Support Mode for predefined SDUsize).

Under the SmpSDU pattern, Iu UP has following function: transmitting user data, initialization, rate controlled, time adjustment, error event are handled and the frame quality classification.Wherein, the purpose of time adjustment process is: the timing relationship of descending transmission data of the Iu UP protocol entity by control CN, reduce the data buffering time in the SRNC at Iu UP entity place, opposite end, and improve the real-time of institute's supporting business.Conversation class and stream class all are that the requirement real-time is than higher business, for these business, the frame number of CN side Iu UP protocol layer is general to be adopted based on lu mouth timing interval (ITI:Iu Timing Interval) form, that is to say the then numbering of present frame=(former frame frame number+1) mod 16 of ITI of every mistake.Here the implication of ITI is the Desired Min Tx Interval between the Iu UP Service Data Unit of a RAB (RAB:Radio Access Bearer), can calculate by following formula for conversation class and stream class ITI:

$\mathrm{ITI}=\frac{\mathrm{MaxSDUsize}}{\mathrm{MaxBitrate}}$

Wherein: MaxSDUsize: be size for the SDU of maximum indicated in the given RAB stream combination (RFCS:RABsub Flow Combination);

MaxBitrate: be transmit the maximum bit rate of data

Therefore frame number is the transmitting time that has reflected each SDU of Iu UP protocol layer of CN side in fact, and the time adjustment process only is based in frame number and just does under the ITI situation.

Time adjustment process under the support mode of 25.415 couples of predefine SDU of 3GPP agreement size, carried out following description:

1) the time adjustment process on the Iu UP is controlled by SRNC.

2) arrive in the unsuitable time when detecting Iu UP Service Data Unit, thereby when causing the time-delay of unnecessary buffering, SRNC is with the allocating time adjustment process.How detecting triggering among the SRNC is the thing of SRNC inside, has exceeded the scope of this agreement.

3) the Iu UP protocol layer among the SRNC is to necessary delay or the lead of peer-entities indication, and step-length is 500 us.

4) after sending Iu UP time regulating frame, watchdog timer T _TA(Time Alignment Timer) opens.This timer is used for the reception of affirmation (Acknowledgement) frame of Looking Out Time adjustment.

5) the requested Iu UP of peer node protocol layer entity is adjusted the timing relationship of descending transmission data according to the indication of SRNC.

6) if the time regulating frame correct format of receiving, and the Iu UP protocol layer of receiving terminal receives, the high-rise time is adjusted carried out correct processing, the acknowledgement frame that the Iu UP protocol layer of receiving terminal is adjusted transmitting time.

7) behind time of receipt (T of R) adjustment acknowledgement frame, the Iu UP protocol layer among the SRNC will stop watchdog timer T _TAFor avoiding the frequent time to adjust, need guarantee behind certain hour, just can initiate the time adjustment process once more.

8) when user data transmission was not hung up by other control procedure, this process can be initiated at any time.

As can be seen, do not stipulate in the agreement how SRNC detects the triggered time and adjust.But the principle that sends Iu UP Service Data Unit by CN side Iu UP protocol layer as can be known, and the actual reception that SRNC can be by Iu UP Service Data Unit constantly and the comparison of the desirable time of reception is judged what whether current transmit frame sent in inappropriate time.SRNC can obtain the time of reception of current Iu UP Service Data Unit, but, how SRNC determines the desirable due in of this Service Data Unit, and how to judge that this Service Data Unit whether being shifted to an earlier date or the reception that lags behind, is that key issue to be solved is arranged.

Summary of the invention

The technical problem to be solved in the present invention provides the time adjusting method of a kind of wireless access network and core network interface user plane, makes SRNC can correctly trigger the allocating time adjustment process, effectively controls the downlink data delivery time of CN.

In order to solve the problems of the technologies described above, the invention provides the time adjusting method of a kind of wireless access network and core network interface user plane, may further comprise the steps:

(a) service wireless network controller is determined a reference frame;

(b) frame number and the due in of the Frame of the current reception of record;

(c) the frame number difference with present frame and reference frame multiply by the timing of lu mouth at interval, add that the reference frame due in obtains the desirable due in of present frame, judge whether the time difference that the present frame due in deducts desirable due in (can be made as very little scope) in the first given scope, if, carry out next step, otherwise, execution in step (e);

(d) do not do the time and adjust, upgrade reference frame, return step (b);

(e) the time adjustment process between triggering and the core net.

Further, in order to reduce accumulated error, in described step (d), be the frame number that the frame number of reference frame is updated to described present frame, the due in of reference frame is updated to the desirable due in of described present frame.

Further, first scope in the described step (c) can be limited by a positive threshold value and a negative threshold value, if present frame lagged behind and arrived, and sends indication time regulating frame in advance to core net in step (e) during greater than described positive threshold value the described time difference; If the described time difference, present frame arrived in advance, sends the time regulating frame that indication lags behind to core net in step (e) during less than described negative threshold value.

Further, in the described step (e), described time regulating frame required time adjustment amount can be taken as the described time difference.

Further, in order to obtain high-precision reference frame, avoid because the reasons such as fluctuation of transmission delay timing inaccuracy, need compare the back to multiframe and determine reference frame, and under accurate prerequisite regularly the real-time update reference frame, for this reason, described step (a) has been adopted following steps and has been determined reference frame:

(a1) frame number and the due in of establishing first frame data is initial reference frame frame number and due in;

(a2) to follow-up present frame, the frame number difference of itself and reference frame be multiply by the timing of lu mouth at interval, add that the reference frame due in obtains the desirable due in of present frame, whether the time difference of judging present frame due in and desirable due in is in second scope of setting, if, carry out next step, otherwise, execution in step (a4);

(a3) thinking this frame regularly accurately, and reference frame is updated to this frame, continue then to handle next frame, reach preset value up to continuous timing accurate data frame number, is reference frame with the last frame, execution in step (c);

(a4) think that this frame bad timing is true, counting continues to handle next frame again.

Further, when the SRNC processing differs too near with Iu UP Service Data Unit due in constantly, can in time handle, can adjust the initiation time, regulate the transmission opportunity of CN, promptly after described step (a2), carry out following steps in order to guarantee downlink data:

(a21) judge that described present frame due in and service wireless network controller handle deviation constantly whether in the 3rd scope of setting, if, execution in step (a3), otherwise carry out next step;

(a22) adjust frame to opposite end lu mouth user plane transmitting time, indication sends in advance, the variable of lead for setting, execution in step (a4) then.

Further; triggered in the described step (e) and core net between the time adjustment process after; judge whether earlier to adjust in the guard time in the time; in this guard time, do not send time regulating frame to core net again; and the subsequent treatment of continuation agreement regulation; in this guard time, continue the processing of next frame, do not send out the adjustment frame.

As from the foregoing, the present invention determines the frame number and the due in of reference frame earlier, does reference with reference frame again, with frame number and the due in and the reference frame comparison of present frame, calculate the deviation of desirable due in and actual due in, thereby judge whether CN needs to carry out the time adjustment.If desired then computing time adjustment amount, transmitting time is adjusted control frame and is given CN.Further, the available high-precision reference frame of statistical method that adopts the present invention to propose.Thereby adjusting function when the present invention has solved the Iu UP that stipulates in the agreement with a kind of simple method can effectively be controlled down link data on the Iu interface to the sequential of SRNC, makes the buffering time delay minimum among the SRNC.

Description of drawings

Fig. 1 is under the support mode, the functional mode figure of Iu mouth user plane protocol layer.

Fig. 2 adjusts the schematic diagram that lags behind and adjust the Iu mouth time.

Fig. 3 adjusts the schematic diagram of adjusting in advance the Iu mouth time.

Fig. 4 is the flow chart that the embodiment of the invention is determined the reference frame that time regulating frame is required.

The process chart that the time was adjusted when Fig. 5 was embodiment of the invention normal data transfer.

Embodiment

Below in conjunction with description of drawings the specific embodiment of the present invention.

Fig. 1 is by the CN of Iu mouth connection and the functional mode figure of UTRAN (wireless access network comprises RNC) Iu UP protocol layer under support mode.As shown in the figure, the Iu UP protocol layer on CN and the RNC all has following 3 class functions:

1) Frame Handler function (Frame Handler function);

2) process control function (Procedure Control functions);

3) at the function (Non AccessStratum Data Streams specific functions) of Non-Access Stratum (NAS:Non Access Stratum) data flow;

The time adjusting function that the present invention relates to is under the jurisdiction of process control function wherein, is used to control down link data on the Iu interface to the sequential of RNC.

Fig. 2, Fig. 3 represent the time adjustment process of SRNC and CN, and wherein PT (i) (Process Time) expression RNC handles constantly.

Among Fig. 2, the actual delivery time of i+1 frame of CN side is early than answering delivery time, the Iu UP of SRNC makes comparisons the actual reception of this frame constantly constantly at PT (i) with the moment that should receive, judge that these frame data shift to an earlier date Delta t and arrive, send out time regulating frame (Time alignment) to CN and indicate its transmission that lags behind; After CN receives this time regulating frame, the acknowledgement frame of adjusting to the SRNC return time (ACK), and accept the adjustment amount of required hysteresis, prolong Delta t behind the delivery time with the i+2 frame.

Among Fig. 3, the actual delivery time of i+1 frame of CN side is later than answers delivery time, the Iu UP of SRNC makes comparisons the actual reception of this frame constantly constantly at PT (i+1) with the moment that should receive, judge that this frame data hysteresis Delta t arrives, and sends out time regulating frame (Time alignment) to CN and indicates it to send in advance; After CN received this time regulating frame, the acknowledgement frame of adjusting to the SRNC return time (ACK), and accept the required adjustment amount that shifts to an earlier date shifted to an earlier date Delta t with the delivery time of i+2 frame.

From the time adjustment process of Fig. 2, Fig. 3 as can be seen: even the transmitting time mistake of certain Iu UP Service Data Unit, the time of carrying out still can be thereafter after adjusting the delivery time of Service Data Unit adjust to and desirablely send the situation generation that all frames after can not causing because of a certain frame delivery time mistake all shift to an earlier date or lag behind constantly.

In order to judge whether CN needs to carry out the time and adjust, and computing time adjustment amount, the present invention at first obtains accurate reference frame with statistical method, determines its frame number and due in; Do reference with reference frame then, with the frame number of present frame and due in and reference frame relatively, calculate the deviation of desirable due in and actual due in, thus need can judge whether adjustment and computing time adjustment amount.

Fig. 4 has described the flow process that present embodiment is determined reference frame.Consider that certain frame data might be because the reasons such as fluctuation of transmission delay inaccuracy regularly need compare the back to multiframe and determine reference frame, and under regularly accurate prerequisite the real-time update reference frame.Also considered the deviation of the SRNC processing moment during this time,, also will adjust the initiation time, regulated the transmission opportunity of CN, can in time handle to guarantee downlink data if differ too near with Iu UP Service Data Unit due in.This flow process may further comprise the steps:

Step 110 writes down the frame number and the due in (being the time of reception) of the Frame of current reception;

Step 120 judges whether current data frame is first frame data of receiving, if, carry out next step, otherwise, execution in step 140;

Step 130 is established reference frame frame for this reason, writes down its frame number and due in, returns step 110 (continuing to handle next frame);

Whether step 140 judges continuously regularly accurately count value TaReferCounter greater than preset value N, if, change normal data over to and receive the handling process (see figure 5), otherwise, next step carried out;

Step 150, present frame due in dwTickArrive is deducted reference frame due in dwTaTickRefer, the difference that obtains deducts the long-pending of present frame and reference frame frame number difference byFrmOffset and ITI again, obtains the time difference TickOffset of this frame due in and desirable due in, that is:

TickOffset＝dwTickArrive-dwTaTickRefer-byFrmOffset*ITI (1)

Simultaneously, calculate this frame due in and handle deviation ProcOffset constantly;

Step 160 is judged TickOffset whether in the scope of setting 1 (being made as very little scope), if, think that this frame accurately arrives, execution in step 180, otherwise carry out next step;

Step 170, put continuous timing accurately count value TaReferCounter be zero, return step 110;

Step 180 is judged ProcOffset whether in the scope of setting 2, if, execution in step 200, otherwise carry out next step;

Step 190, the continuous timing of general count value TaReferCounter accurately adds 1, and upgrading reference frame is this frame, returns step 110;

Step 200, put continuous timing accurately count value TaReferCounter be zero;

Step 210 judges whether to adjust in the guard time in the time, if, return step 110, otherwise, next step carried out;

Step 220 is adjusted control frame to opposite end lu UP transmitting time, and indication sends in advance, and the time that shifts to an earlier date is adopted the variable that can be set by the user, and returns step 110.

Need to prove, the specific implementation step of above-mentioned flow process is adjustable, add and judge after 1 such as also being put into step 180 pair this count value to the continuous timing judgement of count value accurately in the step 140, if directly change the normal data handling process over to greater than preset value.

The time that Fig. 5 describes in the normal data transfer process is adjusted flow process, as shown in the figure, may further comprise the steps:

Step 310 writes down the frame number and the due in (being the time of reception) of the Frame of current reception;

Step 320 with reference to reference frame, is calculated the time difference TickOffset of this frame due in and desirable due in according to present frame frame number and due in, and computational methods are identical with Fig. 4;

Whether step 330 judges TickOffset greater than preset threshold 1 (for positive number), if illustrate that this frame arrives execution in step 360 than desirable the hysteresis constantly; Otherwise, carry out next step;

Whether step 340 judges TickOffset less than preset threshold 2 (for negative), if illustrate that this frame arrives execution in step 370 constantly in advance than desirable; Otherwise, carry out next step;

Step 350, the time of not doing is adjusted, upgrading the reference frame frame number is the frame number of this frame, the reference due in that upgrades reference frame is the desirable due in of this frame, equal former reference frame due in and add the frame number difference of present frame and reference frame and amassing of ITI, be: dwTaTickRefer+byFrmOffset*ITI, return step 310;

Step 360 determines that the next frame transmitting time need shift to an earlier date, and be TickOffset pre-set time, again the step process of stipulating by agreement;

Step 370 determines that the next frame transmitting time needs to lag behind, and be TickOffset lag time, again the step process of stipulating by agreement.

In step 350, be desirable due in rather than its actual due in that the due in of reference frame is updated to present frame, can reduce accumulated error like this.Simultaneously, also make and in normal data reception handling process, needn't judge the present frame due in again and handle deviation constantly, because considered this factor during the due in of the reference frame of before entering Fig. 5 flow process, determining, and the desirable due in of present frame is calculated constantly by this.

In addition, described agreement predetermined process step is as follows:

Judge whether earlier to adjust in the guard time in the time, if, to handle next frame, otherwise send time regulating frame, and start a timer to CN, the stand-by period is adjusted the reception of the acknowledgement frame of frame;

If the time of receipt (T of R) is adjusted not supporting signal, then the Iu UP shut-in time is adjusted function, finishes;

If receiving that requested time is adjusted temporarily can not signal, postpones a time period, judge whether that then still needing to do the time adjusts, if, triggered time adjustment again;

If the acknowledgement frame that the time of receipt (T of R) is adjusted starts a timer, stipulate this timer time to after the time of can carrying out once more adjust;

If the overtime not time of receipt (T of R) is adjusted acknowledgement frame, the frequency of failure adds 1, after the frequency of failure reaches stipulated number, reports to chain of command, and the shut-in time is adjusted function.

Through above-mentioned steps, the Iu UP protocol entity of SRNC simply efficiently solves detection, triggered time adjustment process, after earlier obtaining quite accurately reference frame with statistical method, in the data transmission procedure of reality, can accurate Calculation obtain the definite time quantum that the CN side shifts to an earlier date or lags behind and send and adjust, control the timing relationship of the Iu UP protocol entity data transmission of CN by time regulating frame, reduce the down buffer storage time delay of SRNC, guaranteed the real-time requirement of particular traffic type.Further, frame number and due in by real-time update reference frame in follow-up transfer of data have reduced accumulated error, have avoided mistuning whole.

Above embodiment only is used to illustrate the present invention, but not is used to limit the present invention.

Claims (7)

1. the time adjusting method of wireless access network and core network interface user plane may further comprise the steps:

(a) service wireless network controller is determined a reference frame;

(b) frame number and the due in of the Frame of the current reception of record;

(c) Frame of current reception and the frame number difference of reference frame be multiply by the timing of lu mouth at interval, add that the reference frame due in obtains the desirable due in of Frame of current reception, the Frame due in of judging current reception deducts the time difference of desirable due in whether in the first given scope, if, carry out next step, otherwise, execution in step (e);

(d) do not do the time and adjust, upgrade reference frame, return step (b);

(e) the time adjustment process between triggering and the core net;

Wherein, described step (a) determines that the process of reference frame further may further comprise the steps:

(a1) frame number and the due in of establishing first frame data is initial reference frame frame number and due in;

(a2) to follow-up present frame, the frame number difference of itself and reference frame be multiply by the timing of lu mouth at interval, add that the reference frame due in obtains the desirable due in of present frame, whether the time difference of judging present frame due in and desirable due in is in second scope of setting, if, carry out next step, otherwise, execution in step (a4);

(a3) thinking this present frame regularly accurately, and reference frame is updated to this frame, continue then to handle next frame, reach preset value up to continuous timing accurate data frame number, is reference frame with the last frame, execution in step (b);

(a4) think that this present frame bad timing is true, counting continues to handle next frame again.

2. time adjusting method as claimed in claim 1, it is characterized in that, in the described step (d), be the frame number that the frame number of reference frame is updated to the Frame of described current reception, the due in of reference frame be updated to the desirable due in of the Frame of described current reception.

3. time adjusting method as claimed in claim 1, it is characterized in that, first scope in the described step (c) is limited by a positive threshold value and a negative threshold value, if the described time difference is during greater than described positive threshold value, the Frame of current reception lags behind and arrives, and sends indication time regulating frame in advance to core net in step (e); If the time difference described in the described step (c), the Frame of current reception arrived in advance, sends the time regulating frame that indication lags behind to core net in step (e) during less than described negative threshold value.

4. time adjusting method as claimed in claim 3 is characterized in that, in the described step (e), described time regulating frame required time adjustment amount equals the time difference described in the described step (c).

5. time adjusting method as claimed in claim 1 is characterized in that, described step (a2) back is further comprising the steps of:

(a21) judge that described present frame due in and service wireless network controller handle deviation constantly whether in the 3rd scope of setting, if, execution in step (a3), otherwise carry out next step;

(a22) adjust frame to opposite end lu mouth user plane transmitting time, indication sends in advance, then execution in step (a4).

6. time adjusting method as claimed in claim 5 is characterized in that, is that prompting opposite end lu mouth user plane sends in advance by the time quantum of setting in the described step (a22).

7. time adjusting method as claimed in claim 1; it is characterized in that; triggered in the described step (e) and core net between the time adjustment process after; judge whether earlier to adjust in the guard time in the time; in this guard time, do not send time regulating frame to core net again; and continue the subsequent treatment that agreement is stipulated, and in this guard time, continue the processing of next frame, do not send out the adjustment frame.

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