Summary of the invention
The technical problem that the present invention solves provides the synchronisation control means in a kind of trunked communication system, to introduce the physical layer synchronization control problem under group calling, the multicast scenarios in the trunking communication that solves TD-SCDMA.
For addressing the above problem, the invention provides the synchronisation control means of multicast service in a kind of trunked communication system, comprise step:
A, terminal are obtained the synchronous adjustment information of base station feedback, and adjust the Timing Advance of uplink synchronous according to this synchronous adjustment information;
B, base station measurement have the time of advent of speaking right user's the up shared physical signalling of PTT, and with the expectation the time of advent compare, determine uplink synchronous control command word according to comparative result, and described uplink synchronous control command word is sent to terminal by the PTT Physical Downlink Shared Channel;
C, terminal are controlled the transmitting time of the up shared physical signalling of PTT according to the uplink synchronous control command word that obtains.
The implementation procedure of described steps A is specially:
A1) terminal obtains initial synchronisation according to the signal that the base station issues, and the transmitting time of definite uplink pilot signal;
A2) terminal sends uplink pilot signal according to the transmitting time of described uplink pilot signal to the base station;
A3) transmitting time of base station measurement uplink pilot signal, obtain the time of reception of uplink pilot signal, and calculate the time of reception of described uplink pilot signal and the time-delay deviation that the time of reception of uplink pilot signal is expected in the base station, and with this time-delay deviation notice terminal;
A4) terminal realizes uplink synchronous according to the transmitting time of described time-delay deviation adjustment uplink pilot signal.
Steps A 3) formula that calculates time-delay deviation in is:
UpPCH
POS=UpPTS
Rxpath-UpPTS
TS
Wherein, described UpPTS
RxpathBe that the base station receives the synchronous uplink pilot signal time of initial uplink; Described UpPTS
TSIt is the time that the base station expectation receives uplink pilot signal;
Steps A 4) formula that terminal is adjusted the transmitting time of uplink pilot signal according to time-delay deviation in is:
UpPCH
NEWAVD=UpPCH
OLDAVD+UpPCH
POS-8*16T
C
Wherein, described UpPCH
OLDAVDBe that terminal realizes the initial uplink transmitting time of down definite UpPCH synchronously; Described UpPCH
POSBe the poor of the terminal that receives standard UpPCH time of sending UpPCH time and base station; Described UpPCH
NEWAVDIt is the transmitting time that terminal realizes determining under the accurate uplink synchronous UpPCH.
The content of described synchronous control command word comprises: determine the transmitting time of transmitting time that terminal shifts to an earlier date, hysteresis or keep existing transmitting time.
Terminal is carried out corresponding control according to the content in the described uplink synchronous control command word to uplink synchronous channel.
In addition, the present invention also provides the synchronisation control means of group-calling service in a kind of trunked communication system, and described method comprises step:
A, judge whether the user obtains the right to use of up shared physical channel, if, execution in step B, otherwise, execution in step C;
B, judge whether terminal is assigned to the PTT signaling channel, if, terminal realizes the transmitting time of the up signaling-information of the PTT transmitting time as the up shared physical signalling of PTT up shared physical channel of PTT and the up signaling channel of PTT are carried out identical uplink synchronous control; Otherwise terminal realizes the uplink synchronous control to the up shared physical channel of PTT by sending the Timing Advance that uplink pilot signal obtains uplink synchronous;
If the C terminal only is assigned to the PTT signaling channel, time of advent of base station measurement PTT signaling-information then, and determine uplink synchronous control command word according to measurement result, the PTT signaling channel is carried out corresponding uplink synchronous control.
Terminal described in the step B realizes that with the transmitting time of the up signaling-information of the PTT transmitting time as the up shared physical signalling of PTT the implementation procedure of up shared physical channel of PTT and the up signaling channel of PTT being carried out identical uplink synchronous control is specially:
E1) terminal is with the transmitting time of the up signaling-information of the PTT transmitting time as the up shared physical signalling of PTT;
E2) time of reception of the up shared physical signalling of base station measurement PTT, and with the expectation time of reception compare, determine uplink synchronous control command word according to comparative result, and described uplink synchronous control command word is sent to terminal by the PTT Physical Downlink Shared Channel;
E3) terminal is carried out identical control to the up shared physical channel of PTT with the up signaling channel of PTT according to the described upload control command word that obtains.
Terminal described in the step B realizes the implementation procedure that the uplink synchronous of the up shared physical channel of PTT is controlled is specially by sending the Timing Advance that uplink pilot signal obtains uplink synchronous:
F1) terminal is obtained the synchronous adjustment information of base station feedback, and adjusts the Timing Advance of uplink synchronous according to this synchronous adjustment information;
F2) time of reception of the up shared physical signalling of base station measurement PTT, and with the expectation time of reception compare, determine uplink synchronous control command word according to comparative result, send to terminal by the PTT Physical Downlink Shared Channel;
F3) terminal is controlled the transmitting time of the up shared physical signalling of PTT according to the described uplink synchronous control command word that obtains.
Described step F 1) implementation procedure is specially:
G1) terminal obtains initial synchronisation according to the signal that the base station issues, and the transmitting time of definite uplink pilot signal;
G2) terminal sends uplink pilot signal according to the transmitting time of determining uplink pilot signal to the base station;
G3) transmitting time of base station measurement uplink pilot signal, obtain the time of reception of uplink pilot signal, and calculate the time of reception of described uplink pilot signal and the time-delay deviation that the time that uplink pilot signal receives is expected in the base station, and with this time-delay deviation notice terminal;
G4) terminal realizes uplink synchronous according to the transmitting time of described time-delay deviation adjustment uplink pilot signal.
Step G3) formula that calculates time-delay deviation in is:
UpPCH
POS=UpPTS
Rxpath-UpPTS
TS
Wherein, described UpPTS
RxpathBe that the base station receives the synchronous uplink pilot signal time of initial uplink; Described UpPTS
TSIt is the time that the base station expectation receives uplink pilot signal;
Step G4) formula that terminal is adjusted the transmitting time of uplink pilot signal according to described time-delay deviation in is:
UpPCH
NEWAVD=UpPCH
OLDAVD+UpPCH
POS-8*16T
C
Wherein, described UpPCH
OLDAVDIt is the transmitting time that terminal realizes the UpPCH that initial uplink is determined down synchronously; Described UpPCH
POSBe the poor of the terminal that receives standard UpPCH time of sending UpPCH time and base station; Described UpPCH
NEWAVDIt is the transmitting time that terminal realizes determining under the accurate uplink synchronous UpPCH.
The implementation procedure of described step C is specially:
H1) time of advent of the up signaling-information of base station measurement PTT, and compare with time of advent of expectation, determine uplink synchronous control command word according to relatively result, send to terminal by PTT downlink signaling channel;
H2) terminal is controlled the transmitting time of the up signaling-information of PTT according to uplink synchronous control command word.
The content of described uplink synchronous control command word comprises: determine the transmitting time of transmitting time that terminal shifts to an earlier date, hysteresis or keep existing transmitting time.
In addition, the present invention provides the synchronisation control means of group-calling service in a kind of trunked communication system again, and described method comprises step:
If the A terminal only obtains the right to use of the up shared physical channel of PTT, then terminal is obtained the synchronous adjustment information of base station feedback, and adjusts the Timing Advance of uplink synchronous according to this synchronous adjustment information;
B, base station measurement have the time of advent of the up shared physical signalling of PTT of speaking right terminal, and with the expectation the time of advent compare, determine uplink synchronous control command word according to comparative result, and described uplink synchronous control command word is sent to terminal by the PTT Physical Downlink Shared Channel;
C, terminal are controlled the transmitting time of the up shared physical signalling of PTT according to the uplink synchronous control command word that obtains.
The implementation procedure of described steps A is specially:
A1) terminal obtains initial synchronisation according to the signal that the base station issues, and the transmitting time of definite uplink pilot signal;
A2) terminal sends uplink pilot signal according to the transmitting time of described uplink pilot signal to the base station;
A3) transmitting time of base station measurement uplink pilot signal, obtain the time of reception of uplink pilot signal, and calculate the time of reception of described uplink pilot signal and the time-delay deviation that the time of reception of uplink pilot signal is expected in the base station, and notify described terminal with this time-delay deviation;
A4) terminal realizes uplink synchronous according to the transmitting time of described time-delay deviation adjustment uplink pilot signal.
Steps A 3) formula that calculates time-delay deviation in is:
UpPCH
POS=UpPTS
Rxpath-UpPTS
TS
Wherein, described UpPTS
RxpathBe that the base station receives the synchronous uplink pilot signal time of initial uplink; Described UpPTS
TSIt is the time that the base station expectation receives uplink pilot signal;
Steps A 4) terminal according to the formula of the transmitting time of time-delay deviation modulation uplink pilot signal is in:
UpPCH
NEWAVD=UpPCH
OLDAVD+UpPCH
POS-8*16T
C
Wherein, described UpPCH
OLDAVDIt is the transmitting time that terminal realizes the UpPCH that initial uplink is determined down synchronously; Described UpPCH
POSBe the poor of the terminal that receives standard UpPCH time of sending UpPCH time and base station; Described UpPCH
NEWAVDIt is the transmitting time that terminal realizes determining under the accurate uplink synchronous UpPCH.
The present invention provides the synchronisation control means of group-calling service in a kind of trunked communication system again, and described method comprises step:
If the A terminal obtains the right to use of the up shared physical channel of PTT, and obtain the PTT signaling channel of network allocation, terminal is with the transmitting time of the up signaling-information of the PTT transmitting time as the up shared physical signalling of PTT;
The time of reception of the up shared physical signalling of PTT is passed through to measure in B, base station, and compares with the time of reception of expecting, determines uplink synchronous control command word according to comparative result; And described uplink synchronous control command word is sent to terminal by the PTT Physical Downlink Shared Channel;
C, terminal are carried out identical control to the up shared physical channel of PTT with the up signaling channel of PTT according to the described uplink synchronous control command word that obtains.
Compared with prior art, the present invention has following beneficial effect: the PTT channel that the present invention is directed to increase has proposed synchronisation control means, particularly to the Synchronization Control of channel uplink.This up Synchronization Control comprises two processes: the process of setting up of uplink synchronous and maintenance process.But, in the control procedure of carrying out uplink synchronous, the process of setting up of initial uplink synchronous is necessary, be exactly that terminal is by sending the time of reception of UpPTS data, base station measurement terminal transmission UpPTS data, compare by time of reception with expectation, obtain the time-delay deviation of the two, and this time-delay deviation feeds back to terminal by FPACH, terminal is adjusted the time that sends data accordingly according to the time-delay deviation that obtains, terminal obtains initial uplink synchronous, this shows that it is necessary obtaining initial uplink synchronous process, otherwise system can't work.Then, on the synchronous basis of initial uplink, carry out the process that uplink synchronous keeps, the maintenance of described uplink synchronous can be according to the time of advent of up signaling-information of PTT or up shared physical signalling, and the time of advent of its measurement and the time of advent of expectation compared, and the result that will compare determines uplink synchronous control command word (comprising), and give terminal by corresponding channel feedback with this uplink synchronous command word, terminal is adjusted the transmitting time of signal accordingly according to the uplink synchronous control command word that receives, to realize the maintenance of uplink synchronous.Described synchronous control command word is a kind of function of enhancing property, and the base station is the receiving position of control terminal signal accurately, improves receptivity.
Embodiment
Core of the present invention is at Time Division-Synchronous Code Division Multiple Access (TD-SCDMA, during Time-DivisionSynchronization Code Division-Multiple-Access) as trunking communication, with respect to traditional cellular communication system, and the new multicast and the business demand of group calling have been introduced, the different synchronous control mode that the present invention adopts carries out Synchronization Control to the new physical layer of introducing business, with the receiving position of control terminal signal accurately, thereby reduce the receptivity of terminal.The Synchronization Control of described TD-SCDMA group system can be divided into uplink synchronous control and down-going synchronous control.Need to prove, because the cdma system downstream signal itself is exactly synchronous, so the downstream signal of TD-SCDMA group system also is synchronous, described down-going synchronous control is meant that terminal and base station keep synchronously with the signal that send the base station in other words, and down-going synchronous is the prerequisite and the basis of uplink synchronous.In group system of the present invention, down-going synchronous control is as broad as long with traditional TD-SCDMA mobile communication system, all be to finish by downlink pilot frequency channel DwPCH and Traffic Channel or Primary Common Control Physical Channel (P-CCPCH, Primary CommonControl Physical Channel) channel.Therefore, the present invention only relates to uplink synchronous control.And uplink synchronous control generally comprises two processes, promptly up process and the up maintenance process set up.
Below in conjunction with accompanying drawing the present invention is done the present invention is described further.But, need explanation to be: in fact the up shared physical signalling of transmission PTT of the present invention, the up signaling-information of PTT and PTT signaling-information etc. are respectively: send signal, the signal of the up signaling channel of PTT and the signal of PTT signaling channel etc. of the up shared physical channel of PTT, no longer repeat in the following description.
Please refer to Fig. 1, be the flow chart of the synchronisation control means of multicast service in the trunked communication system of the present invention; Described method comprises step:
Step R10: terminal is obtained the synchronous adjustment information of base station feedback, and adjusts the transmitting time of uplink synchronous according to this synchronous adjustment information, finishes uplink synchronous;
Step R11: base station measurement has the PTT PoC (PTT of speaking right terminal, push-to-talk) time of advent of up shared physical signalling, and with its with the expectation time of advent compare, and comparative result determined uplink synchronous control command word, send to terminal by the PTT Physical Downlink Shared Channel;
Step R12: terminal is controlled the transmitting time of the up shared physical signalling of PTT according to the uplink synchronous control command word that obtains.
Uplink synchronous control of the present invention further comprises: the foundation of uplink synchronous and the maintenance of uplink synchronous.The process of setting up of described uplink synchronous is compared as broad as long with traditional TD-SCDMA mobile communication system, each user in the group is by emission ascending pilot channel UpPCH, the base station feeds back to terminal by physical access channel FPACH with synchronous adjustment information, terminal is finished accurate uplink synchronous according to the Timing Advance of the feedback adjusting information adjustment uplink synchronous of base station.That is to say, each user initiates request by ascending pilot channel in the terminal multicast, when the base station monitors when request at ascending pilot channel, the time-delay deviation of assessment terminal, obtain the initial uplink signal sending time that uplink synchronous is set up according to described deviation result, and should the time begin to send data as the transmitting time of the up shared physical signalling of PTT.Its concrete implementation procedure comprises:
A1, terminal receive base station transmit signals, and according to received signal, obtain frame synchronization (because propagation delay time, the frame head position of terminal and the frame head position of base station have deviation), and promptly obtaining rough uplink synchronous (is UpPCH
OLDAVD), determine the transmitting time of ascending pilot channel UpPCH;
A2, terminal send the UpPCH data according to determining the UpPCH transmitting time;
The UpPCH data that a3, base station measurement terminal send, obtain the UpPCH time of reception, the UpPCH time of reception of this time of reception and base station is variant, promptly have time-delay deviation in time between second, the standard that the UpPCH time that the terminal that described time-delay deviation equals to receive sends deducts the base station receives the UpPCH time;
A4, base station are notified terminal by rapid physical receive channel FPACH with time-delay deviation;
After a5, terminal obtain time-delay deviation,, adjust the time that terminal sends uplink pilot signal, finish accurate uplink synchronous according to time-delay deviation.
The concrete of time-delay deviation of the present invention is defined as: Received SYNC-UL TimingDeviation ' is the time difference, and the formula of its calculation delay deviation is:
UpPCH
POS=UpPTS
Rxpath-UpPTS
TS
Wherein, described UpPTS
RxpathBe that the base station receives the synchronous uplink pilot signal time (time of the reception in the Node B of the SYNC-UL to be used in the uplinksynchronization process) of initial uplink; Described UpPTS
TSIt is the time (time instance two symbols prior to the end of the DwPCH according to theNode B internal timing) that the base station expectation receives uplink pilot signal.
And terminal obtains time-delay deviation UpPCH
POSAfter, according to described time-delay deviation, pass through formula:
UpPCH
NEWAVD=UpPCH
OLDAVD+UpPCH
POS-8*16T
C
Adjust the transmitting time that terminal sends uplink pilot signal, finish accurate uplink synchronous.Wherein, described UpPCH
OLDAVDBe exactly the transmitting time that terminal realizes UpPCH definite under the rough uplink synchronous, UpPCH
NEWAVDIt is the transmitting time that terminal realizes UpPCH definite under the accurate uplink synchronous.But why the present invention also will be by deducting 8*16T in above-mentioned formula
CAdjust the time that terminal sends uplink pilot signal, this is because in actual applications, the standard of base station receives the UpPTS of UpPCH time ratio definition
TS8 symbol that lagged behind (equal 8*16T on the time
C), the standard of base station receives UpPCH time=UpPTS
TS+ 8*16T
CSo, UpPCH
POSBe not that real time-delay deviation (but has differed from 8*16T
C), therefore, the formula that terminal is accurately adjusted the transmitting time of uplink pilot signal is UpPCH
NEWAVD=UpPCH
OLDAVD+ UpPCH
POS-8*16T
C
But why not the present invention directly defines the base station standard and receives the UpPCH time, and this is because in present standard criterion, and base station standard time of reception has been had UpPTS
TSDefinition, for do not occur the conflict, the present invention does not introduce new definition again, but explains with original definition.Simple, described UpPTS
TSBe in advance in the time point of two symbol of DwPCH end point, just in advance in the time point (the UpPTS time of reception of standard lags behind 6 symbol of DwPCH end point) of 8 symbol of the UpPTS of standard time of reception.
The present invention begins to carry out the maintenance of uplink synchronous after finishing accurate uplink synchronous (being that uplink synchronous is set up).In multicast, owing to have only a user to have speaking right (describe for convenient, claim that this user is user A), therefore, have only user A to take the up shared physical channel of PTT, also have only user A to need uplink synchronous control.The transmitting time of the up shared physical channel of base station measurement PTT, measurement result according to the up shared physical channel of PTT, and this measurement result and the time that wish to arrive compared, and according to comparative result generation uplink synchronous control command word, be transmitted to user A by the PTT Physical Downlink Shared Channel, user A obtains uplink synchronous control command word by demodulation PTT Physical Downlink Shared Channel, and ascending pilot channel is carried out corresponding uplink synchronous adjustment.All the other users receive only the PTT Physical Downlink Shared Channel, and abandon synchronous control command word wherein.Wherein, realize being specially of uplink synchronous maintenance:
B1: the time of advent of the up shared physical signalling of base station measurement PTT; Its concrete method of measurement mainly is: the base station is detected receiving data, can obtain the time of advent of received signal.Wherein, the detection method of described reception data, be meant and utilize the given data that receives data, the recipient carries out matched filtering with given data to receiving data, and to maximizing among the result of matched filtering, the time of reception point of maximum correspondence is exactly the time of advent of the up shared physical signalling of PTT, this method for a person skilled in the art, be disclosed technology contents, to this, the present invention does not remake detailed explanation.
B2: the base station is according to the time of advent of measuring, compare with the time of advent of expectation, determine uplink synchronous control command word, determine promptly to wish that terminal shifts to an earlier date or the transmission data that lag behind according to comparative result, or keep existing transmitting time, produce the synchronous control command word thus;
B3: the base station is by PTT Physical Downlink Shared Channel transmitting control commands word;
B4: after terminal obtains the control command word,, just keep transmitting time constant if the base station requires to keep; If the base station requires to lag behind and sends, fixing step-length (as 1/8chip, this is measured by network configuration) lags behind on existing transmitting time; If the base station requires to send in advance, shift to an earlier date the fixing step-length (as 1/8chip, this is measured by network configuration) in back in existing transmitting time.
In addition, the present invention also provides the synchronisation control means of group-calling service in a kind of trunked communication system, and the flow chart of described method sees Fig. 2 for details, and described method comprises step:
Step S10: judge whether terminal obtains the right to use of the up shared physical channel of PTT, if, execution in step S12, otherwise, execution in step S11;
Step S11: time of advent of base station measurement PTT signaling-information then, and determine uplink synchronous control command word according to measurement result, and the PTT signaling channel is carried out corresponding uplink synchronous control, finish;
Step S12: judge whether terminal is assigned to the PTT signaling channel, if be assigned to, execution in step S13 then; Otherwise, execution in step S14;
Step S13: terminal realizes the transmitting time of the up signaling-information of the PTT transmitting time as the up shared physical signalling of PTT up shared physical channel of PTT and the up signaling channel of PTT are carried out identical uplink synchronous control;
Step S14: when terminal was had to the right to use of the up shared physical signalling of PTT, the user realized the uplink synchronous control to the up shared physical channel of PTT by sending the Timing Advance that ascending pilot channel obtains uplink synchronous.
The uplink synchronous control of described group-calling service also comprises two processes, and promptly uplink synchronous is set up process and uplink synchronous maintenance process.It is identical with the implementation procedure of multicast service that described group-calling service uplink synchronous is set up process, specifically sees the implementation procedure of the uplink synchronous foundation of above-mentioned multicast service for details, here do not giving unnecessary details.And the control procedure of uplink synchronous and multicast service is inequality.Because in group-calling service, the user need be by seizing the up shared physical channel of PTT, and just can use the up shared physical channel of PTT after the network approval.And whether use the user of the up shared physical channel of PTT according to the user, uplink synchronous control is different.
First kind is: when terminal does not obtain the right to use of the up shared physical channel of PTT, if network has been terminal configuration PTT signaling channel then need carry out uplink synchronous control for the PTT signaling channel; If network does not dispose the PTT signaling channel for the user, then terminal just receives descending channel information, need not carry out the uplink synchronous control procedure.Therefore, when terminal did not obtain the right to use of the up shared physical channel of PTT, if network has been terminal configuration PTT signaling channel, then the implementation procedure of uplink synchronous was:
C1: the time of advent of the up signaling-information of base station measurement PTT; Its concrete method of measurement mainly is: the base station is detected receiving data, can obtain the time of advent of received signal.Wherein, for the detection method (ditto described) that receives data, for a person skilled in the art, be disclosed technology contents, to this, the present invention does not remake detailed explanation.
C2: the base station is determined to wish that terminal shifts to an earlier date or the transmission that lags behind, or is kept existing transmitting time according to comparing the time of advent of the time of advent of measuring and expectation, produces the synchronous control command word thus
C3: the base station sends the synchronous control command word by PTT downlink signaling channel;
C4: after terminal obtained the synchronous control command word, if the base station requires to keep, it is constant that then terminal just keeps the up signaling-information transmitting time of PTT; If lagging behind, the base station requirement sends, then the terminal step-length (as 1/8chip, this is measured by network configuration) that hysteresis is fixed on the transmitting time of the existing up signaling-information of PTT; If the base station requires to send in advance, then terminal is in the fixing in advance step-length (as 1/8chip, this is measured by network configuration) of the transmitting time of the existing up signaling-information of PTT.
Second kind is: when terminal by seizing, obtain the right to use of the up shared physical channel of PTT after, can be divided into two kinds of situations, 1 in this case again) the kind situation: network has been this terminal distribution PTT signaling channel; 2) kind situation: network does not distribute the PTT signaling channel for this user.Describe respectively at both of these case below.
1) kind situation: if after this terminal obtained the right to use of the up shared physical channel of PTT, network did not distribute the PTT signaling channel for this terminal.This situation comprises two processes:
First process is the process of setting up of uplink synchronous: at first terminal need be by sending UpPCH, and the base station is replied FPACH and obtained initial synchronisation then, specifically with the process of setting up of the top described uplink synchronous of multicast.Here repeat no more.But, after setting up process synchronously, carry out the maintenance of uplink synchronous by the up shared physical channel of PTT.Just, the up shared physical channel of base station measurement PTT, measurement result according to the up shared physical channel of PTT, and this measurement result and the time that wish to arrive compared, produce up synchronous control command word, by the emission of PTT Physical Downlink Shared Channel, terminal demodulation PTT Physical Downlink Shared Channel, obtain up synchronous control command word, carry out the uplink synchronous adjustment accordingly.
Second process is the process that uplink synchronous keeps: this process and above-mentioned terminal do not obtain under the situation of speaking right, the process that uplink synchronous kept when then network was terminal distribution PTT signaling channel is similar, just base station measurement is the time of reception of up shared physical signalling, and up shared physical channel controlled, send the synchronous control command word by descending shared physical signalling.Concrete implementation procedure is:
D1: the time of advent of the up shared physical signalling of base station measurement PTT; Its concrete method of measurement mainly is: the base station is detected receiving data, can obtain the time of advent of received signal.Wherein, to receiving the detection method of data, for a person skilled in the art, be disclosed technology contents, to this, the present invention does not remake detailed explanation.
D2: the base station is determined to wish that terminal shifts to an earlier date or the transmission that lags behind, or is kept existing transmitting time according to comparing the time of advent of the time of advent of measuring and expectation, produces the synchronous control command word thus
D3: the base station sends the synchronous control command word by the PTT Physical Downlink Shared Channel;
D4: after terminal obtained the synchronous control command word, if the base station requires to keep, it is constant that then terminal just keeps the up shared physical signalling transmitting time of PTT; If lagging behind, the base station requirement sends, then the terminal step-length (as 1/8chip, this is measured by network configuration) that hysteresis is fixed on the transmitting time of the existing up shared physical signalling of PTT; If the base station requires to send in advance, then terminal is in the fixing in advance step-length (as 1/8chip, this is measured by network configuration) of the transmitting time of the existing up shared physical signalling of PTT.
2) kind situation: if after this terminal obtained the right to use of the up shared physical channel of PTT, network was this terminal distribution PTT signaling channel.This situation also comprises two processes:
First process is the maintenance process of uplink synchronous: terminal is by the process of setting up synchronously of PTT signaling channel, obtain the Timing Advance of uplink synchronous, terminal is used the up Timing Advance transmission data of the Timing Advance of the up signaling-information of described PTT as the up shared physical channel of PTT.After bringing into use the up shared physical channel of PTT to send data, the up shared physical signalling time of reception of base station measurement PTT, measurement result according to the up shared physical channel of PTT, and this measurement result and the time of reception that wish to arrive compared, produce up synchronous control command word, by the emission of PTT Physical Downlink Shared Channel, terminal demodulation PTT Physical Downlink Shared Channel, obtain up synchronous control command word, carry out the uplink synchronous adjustment accordingly.The up signaling channel of PTT adopts the uplink synchronous time adjustment amount identical with the up shared physical channel of PTT.
This implementation procedure with do not distribute the PTT signaling channel different, saved the process of setting up that obtains uplink synchronous by FPACH, directly use the transmitting time of the up signaling-information of PTT to be used as the transmitting time of up shared physical signalling.Thereby improved the receptivity of terminal.
Second maintenance process that process is a uplink synchronous: this process and 1) second process of kind situation is consistent, it also is the time of reception of the up shared physical signalling of base station measurement, up shared physical signalling is controlled, sent the synchronous control command word by descending shared physical signalling.Terminal is carried out identical adjustment to up shared physical channel with up signaling channel according to the synchronous control command word of base station, and the synchronous control command word in the PTT downlink signaling channel abandons.Its specific implementation process sees 1 for details) plant second process of situation, here repeat no more.
And, receive only the PTT Physical Downlink Shared Channel for not obtaining the usufructuary terminal of the up shared physical channel of PTT, wherein synchronous control command word is abandoned.
By above-mentioned two kinds of situations as can be known, for obtaining the usufructuary terminal of the up shared physical channel of PTT, no matter distribute the PTT signaling channel or do not distributed the PTT signaling channel, after new terminal uses PTT to share physical channel, in the Synchronization Control of base station, need carry out the control of uplink synchronous to new terminal according to the coming into force a little of the speaking right of new terminal, mainly be that time of reception point to above-mentioned signal averages calculating, with the time of reception point generation control command word after average.The process of its average computation it be: x
n=(1-p) x
N-1+ px
n(1)
N express time point wherein, x
nThe mean value of representing the n frame, p are the average factors, obtain according to emulation, get 1/15 now, x
N-1The mean value of representing the n-1 frame, x
nThe time of reception point of representing the n frame.
When new terminal was controlled, initial time was not because there is the mean value of previous frame,, was expressed as formula and was exactly as mean value with the time of reception point of present frame: x
0=x
0
The follow-up time just can be passed through above-mentioned formula (1) calculating mean value, carries out Synchronization Control according to mean value.
In addition, the present invention provides the synchronisation control means of group-calling service in a kind of trunked communication system again, and the flow chart of described method sees Fig. 3 for details, and described method comprises step:
Step M10: if terminal only obtains the right to use of the up shared physical channel of PTT, then terminal is obtained the synchronous adjustment information of base station feedback, and adjusts the Timing Advance of uplink synchronous according to this synchronous adjustment information;
Step M11: base station measurement has the time of advent of the up shared physical signalling of PTT of speaking right terminal, and with the expectation the time of advent compare, determine uplink synchronous control command word according to comparative result, and described uplink synchronous control command word is sent to terminal by the PTT Physical Downlink Shared Channel;
Step M12: terminal is controlled the transmitting time of the up shared physical signalling of PTT according to the uplink synchronous control command word that obtains.
The implementation procedure of described step M10 is specially:
Step M100: terminal obtains initial synchronisation according to the signal that the base station issues, and the transmitting time of definite uplink pilot signal;
Step M101: terminal sends ascending pilot channel according to the transmitting time of described uplink pilot signal to the base station;
Step M102: the transmitting time of base station measurement uplink pilot signal, obtain the time of reception of uplink pilot signal, and calculate the time of reception of described uplink pilot signal and the time-delay deviation that the time of reception of uplink pilot signal is expected in the base station, and notify described terminal with this time-delay deviation;
Step M103: terminal realizes uplink synchronous according to the transmitting time of described time-delay deviation adjustment uplink pilot signal.
The formula that wherein calculates time-delay deviation among the step M102 is:
UpPCH
POS=UpPTS
Rxpath-UpPTS
TS
Wherein, described UpPTS
RxpathBe that the base station receives the synchronous uplink pilot signal time of initial uplink; Described UpPTS
TSIt is the time that the base station expectation receives uplink pilot signal;
Terminal according to the formula of the transmitting time of time-delay deviation modulation uplink pilot signal is among the step M103:
UpPCH
NEWAVD=UpPCH
OLDAVD+UpPCH
POS-8*16T
C
Wherein, described UpPCH
OLDAVDIt is the transmitting time that terminal realizes the UpPCH that initial uplink is determined down synchronously; Described UpPCH
POSBe the poor of the terminal that receives standard UpPCH time of sending UpPCH time and base station; Described UpPCH
NEWAVDIt is the transmitting time that terminal realizes determining under the accurate uplink synchronous UpPCH.
The specific implementation process of the method for the invention is same as above, here repeats no more.
In addition, the present invention provides the synchronisation control means of group-calling service in a kind of trunked communication system again, and the flow chart of described method sees Fig. 4 for details, and described method comprises step:
Step N10: if terminal obtains the right to use of the up shared physical channel of PTT, and obtain the PTT signaling channel of network allocation, terminal is with the transmitting time of the up signaling-information of the PTT transmitting time as the up shared physical signalling of PTT;
Step N11: the base station is by measuring the time of reception of the up shared physical signalling of PTT, and with the expectation time of reception compare, determine uplink synchronous control command word according to comparative result, and described uplink synchronous control command word is sent to terminal by the PTT Physical Downlink Shared Channel;
Step N12: terminal is carried out identical control to the up shared physical channel of PTT with the up signaling channel of PTT according to the described uplink synchronous control command word that obtains.
The specific implementation process of the method for the invention is same as above, here repeats no more.
Therefore, PTT business of the present invention belongs to a kind of business of new introducing for the TD-SCDMA trunked communication system, has also introduced the PTT channel simultaneously and (has comprised PTT up-downgoing signaling channel.Physical channel is shared in the PTT up-downgoing) etc. several new channels, at these channels, in present prior art, also do not have the Synchronization Control scheme.Therefore, the PTT channel that the present invention is directed to increase has proposed synchronisation control means, particularly the technical scheme that uplink synchronous is controlled.At first, in the control procedure of carrying out uplink synchronous, the process of setting up of initial uplink synchronous is necessary, be exactly that terminal is by sending the time of reception of UpPTS data, base station measurement terminal transmission UpPTS data, compare by time of reception with expectation, obtain the time-delay deviation of the two, and this time-delay deviation feeds back to terminal by FPACH, terminal is adjusted the time that sends data accordingly according to the time-delay deviation that obtains, terminal obtains initial uplink synchronous, this shows that it is necessary obtaining initial uplink synchronous process, otherwise system can't work.Then, carry out the process that uplink synchronous keeps on the synchronous basis of initial uplink, base station feedback synchronous control command word is a kind of function of enhancing property, and the base station is the receiving position of control terminal signal accurately, improves receptivity.In addition, the realization of synchronous maintenance process of the present invention, the variation of up transmitting time is released in the variation that can also measure the time of reception of downstream signal by terminal, adjusts the transmitting time of terminal accordingly, and this method also can realize the Synchronization Control process.
The above only is a preferred implementation of the present invention; should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the principle of the invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.