CN101193425B - Method and system for CDMA system terminal to realize remote switch under TDD - Google Patents
Method and system for CDMA system terminal to realize remote switch under TDD Download PDFInfo
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- CN101193425B CN101193425B CN200610145035XA CN200610145035A CN101193425B CN 101193425 B CN101193425 B CN 101193425B CN 200610145035X A CN200610145035X A CN 200610145035XA CN 200610145035 A CN200610145035 A CN 200610145035A CN 101193425 B CN101193425 B CN 101193425B
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Abstract
The invention relates to a switch method for realizing long-distance switch of a CDMA system terminal under TDD and s system thereof. The method includes the processes: an MDM judges whether the terminal supports the long-distance switch or not; the MDM searches and monitors adjacent frequency base stations in the range of added synchronous searching; the MDM calculates the distance between the current terminal and the adjacent frequency base stations according to monitoring results of the adjacent frequency base stations; an MCU selects a target base station which needs to be switched according to the monitoring results of the adjacent frequency base stations and the distance between the current terminal and the adjacent frequency base stations; the MDM selects a distance mode and access parameters to access the target base station according to the distance between the current terminal and the target base station. The system consists of the MDM and the MCU which respectively has a switch-control unit, wherein, the switch-control unit of the MDM includes an adjacent frequency monitoring module, a power estimation module and a distance calculation module. By adopting the invention, the existing system resource can be effectively utilized; the adjacent frequency base stations realizing the current terminal can be effectively searched for and used.
Description
Technical field
The terminal that the present invention relates under a kind of cdma system realizes remote changing method and the system of switching, and the cdma system terminal that relates in particular under a kind of TDD realizes remote changing method and the system of switching.
Background technology
Cdma system under the TDD, for example the switching of SCDMA system is initiated by terminal, and switching mode is a direct-cut operation.In the cdma system under the TDD, no matter be that the selection course that terminal itself is initiatively selected better base station or is forced to carry out the base station all will experience the signal monitoring stage of current base station, adjacent search and the supervision stage and the switch step of base station frequently, and the base station helps out in this handoff procedure.The switched system structure that cdma system terminal under the relevant TDD is normally switched as shown in Figure 1, in the signal monitoring stage, little processing and control element (PCE) (MCU) of terminal monitors the signal of current base station, and promptly signal to noise ratio (snr), the power of the downstream signal that current terminal is received are periodically added up; Simultaneously the supervision of relevant descending power and signal to noise ratio is also carried out in the adjacent base station frequently of current base station; If the decision-making module of terminal MCU thinks that the signal conditioning of current base station has not been that enough good or adjacent signal of base station frequently is better than current base station, then needs current terminal to seek the better base station of signal conditioning and switches.In the search phase of neighbour's frequency base station, the modem module of terminal (MDM) filters out the adjacent preferably frequency of base station frequently of several signal conditionings and switches trial; Wherein, the adjacent process of search frequently is divided into rougher process and two steps of refining process; That is, at first, by a process of roughly selecting the frequency of adjacent frequency base station, promptly the MDM of terminal scans 40 adjacent frequencies of base stations frequently one time within several frames, forms an adjacent base station frequency point table frequently that is suitable for current terminal fast; Then, the MDM of terminal carries out accurate power respectively to this adjacent each frequency of table frequently in neighbour's frequency base station and estimates, obtains the adjacent frequency base station sequence of an adjacent performance number frequently of foundation queuing.After obtaining this neighbour's frequency base station sequence, whether the MCU of terminal initiates to switch by the method decision of power and the suitable weighting of signal to noise ratio according to the performance number of neighbour's frequency base station, and initiates switching to the base station of which frequency.
In the cdma system under the TDD, what guard system did not use is soft handover or direct-cut operation, does not all point out under the existing systems resource, how to support farther apart from the switching between the base station by maximum using system resource.For example, using the 400M or the mountain area of 1800M system, following predicament might appear, as: there are two 400M base station A and B in the somewhere, and the user is in base station A conversation, and signal is stopped by mountain when moving to from this base station 5km, and have this moment 30km base station B signal at a distance pretty good, but owing to be subject to the synchronous searching scope of 30chip, user terminal can't switch to base station B, thereby can not maximum using system resource.For the also similar situation of the system of 1800M.Obviously, prior art and pertinent literature, just the criterion that should follow when switching selection system has been carried out the principle description, does not propose one aspect the maximum using system resource and how by utilizing the system resource support farther apart from the switching between the base station; Particularly, do not propose how to take all factors into consideration under the various situations, realize the optimization of system resource and adjust the switching of supporting distance between the farther base station at the cdma system under the TDD.
In view of the above problems, the cdma system terminal energy maximum using system resource realization that is necessary to design in fact under a kind of TDD is farther apart from changing method that switches between the base station and switched system, and this will can produce important influence to the optimization and the layout of network.
Summary of the invention
The object of the present invention is to provide the cdma system terminal under a kind of TDD to realize remote changing method and the system of switching, the present invention is by synchronous searching scope that increases adjacent base station frequently and the uplink synchronous mechanism of adjusting terminal, realize current terminal can with adjacent base station frequently can effectively be searched and be carried out utilization.
The present invention also aims to provide the cdma system terminal under a kind of TDD to realize remote changing method and the system of switching, in the process of switching, the present invention by to the information of the adjacent base station frequently of current terminal as distance, number of users, the isoparametric collection of power, reasonable parameter configuration is linked into better purpose base station quickly to realize selecting more current terminal in the process of switching.
For achieving the above object, the cdma system terminal that the present invention proposes under a kind of TDD realizes the remote changing method that switches, and comprises the steps:
Step 1: the MDM of terminal judges whether described terminal supports remote switching, if support that then execution in step 2; Otherwise, carry out existing switching flow;
Step 2: described modem module is determined the synchronous searching scope that described remote switching is required according to the ultimate range of the base station of described remote switching support search;
Step 3: described MDM searches for and monitors in the base station frequently the neighbour in described synchronous searching scope;
Step 4: described MDM calculates the distance of current terminal apart from neighbour's frequency base station according to neighbour's frequency base station monitoring result;
Step 5: the MCU of terminal apart from neighbour's distance of base station frequently, selects the target BS that switches according to described adjacent base station monitoring result frequently and current terminal;
Step 6: described MDM selects corresponding distance mode and access parameter to insert to target BS according to the distance of current terminal and target BS.
Wherein, in described step 2, the ultimate range of the base station of described remote switching support search can be configured according to described system by webmaster.
Further, in described step 3, before neighbour's frequency base station being searched for and monitored, need to carry out following steps earlier:
Step a: described MDM receives the processing time slot to it and compensates according to described synchronous searching scope;
Step b: described MDM is according to described synchronous searching scope, and the adjacent pilot channel of base station frequently that signal is dropped in the described synchronous searching scope carries out the power estimation.
Wherein, described step a is specially:
Step a1: described MDM determines that described synchronous searching scope is with respect to the recruitment of not supporting remote switching terminal;
Step a2: described MDM, adjusts terminal and receives the length of handling time slot under the prerequisite that the overall time slot that guarantees the terminal time slot remains unchanged according to described recruitment;
Step a3: described MDM receives the processing time slot to it and compensates according to terminal is received the adjustment amount of handling slot length.
Wherein, described step b is specially:
Step b1: described MDM distinguishes the different operating state of current terminal, and the data of the symbol lengths of M before the synchronizing symbol are carried out DC processing;
Step b2: described MDM increases the length of N symbol in the synchronous synchronous points position of terminal and current base station, obtain another synchronous points position;
Step b3: described MDM is a benchmark with described another synchronous points position, estimates that (M+N) of synchronizing symbol power individual or the individual symbol of the [(M+1)+N] is equivalent to the power of synchronizing symbol, and with this adjacent power of base station frequently that receives as terminal.
Wherein, described M is the positive integer between 2～4; According to the requirement of described system and the accuracy of rated output, described N is the positive integer more than or equal to 1; The length of perhaps described N symbol is the mean value of the length of N symbol.
Further, in described step 6, described access parameter comprises selection, the selection of far and near distance pattern and the selection of transmitting power etc. of some launch time at least, wherein:
The selection of launch time point is the high order end that terminal signaling that target BS is received falls into the target BS search window, makes the coverage of base station reach maximum;
The selection of far and near distance pattern is: if the distance of current terminal distance objective base station is then selected closely access module less than 23.4 kms; If the distance of current terminal distance objective base station is then selected remote access module greater than 35.1 kms; If the distance of current terminal distance objective base station between 23.4 kms and 35.1 kms, is then selected remote access module or a kind of in the access module closely;
The selection of transmitting power is to make its interference to system reach minimum; Wherein, described MDM can attempt the transmitting power that access sequence is determined terminal according to terminal on the basis of the power of the target BS of its calculating.
Further, described step 6 is specially:
Described MDM is according to the distance of current terminal and target BS, selects corresponding distance mode (and be earlier remote access module in the different prior art, after closely access module); Simultaneously,
Described MDM arrives the time delay of current terminal according to the distance estimations target BS downstream signal of current terminal and target BS, and then determines corresponding launch time of point; Afterwards,
Described MDM initiates to divide frame access or overstepping one's bounds frame to insert according to the transmitting power that the power of the target BS of its calculating is determined to target BS.
Further, in the described access procedure of described step 6, on the synchronous basis of current terminal and target BS, also comprise:
Described MDM distinguishes the different operating state of current terminal, and according to the deviation of synchronous points and the concrete scope of search thereof, under the prerequisite that the length that guarantees the terminal receiving slot remains unchanged, the receiving slot of terminal is adjusted; And
Described MDM determines the data that receive are carried out the starting position of the actual demodulation point of corresponding demodulation.
Wherein, the starting position of described definite actual demodulation point is specially:
Steps A: described MDM estimates synchronous points when the position on the right side of described synchronous searching scope, the difference of the position of synchronous points and the starting position of real data;
Step B: described MDM determines the starting position of described actual demodulation point according to the position and the described difference on the described right side; The starting position that is described actual demodulation point is that the length of described synchronizing symbol deducts the position on the described right side and the difference of described difference.
For achieving the above object, the cdma system terminal that the present invention proposes again under a kind of TDD realizes the remote switched system that switches, comprise the MDM and the MCU that have switch control unit respectively, the switch control unit of wherein said MDM comprises that the monitor adjacent frequency module reaches the power estimation module of carrying out information interaction with described monitor adjacent frequency module, the switch control unit of described MCU comprises adjacent base station monitoring result's the decision-making module frequently that receives described monitor adjacent frequency module transmission, it is characterized in that the switch control unit of described MDM also comprises:
Carry out the distance calculation module of information interaction with described monitor adjacent frequency module, be used to calculate current terminal apart from neighbour's distance of base station frequently;
Wherein, described monitor adjacent frequency module is searched for and is monitored in the base station frequently the neighbour in the synchronous searching scope that described MDM determines; Wherein, described synchronous searching scope is determined according to the ultimate range of the base station of described remote switching support search by described MDM.
Further, described decision-making module is used for according to described adjacent base station monitoring result frequently and current terminal selecting the target BS that switches apart from neighbour's distance of base station frequently; Described power estimation module is used for according to described synchronous searching scope, and the adjacent pilot channel of base station frequently that signal is dropped in the described synchronous searching scope carries out the power estimation; And also be used to distinguish the different operating state of current terminal, and, under the prerequisite that the length that guarantees the terminal receiving slot remains unchanged, the receiving slot of terminal adjusted according to the deviation of synchronous points and the concrete scope of search thereof.
When portable terminal (MS) or arbitrarily terminal in the process that moves, if cross over adjacent sectors, adjacent sub-district and under the situation about switching, adopt changing method of the present invention and system can realize the more search of multiple target base station; The present invention adjusts the control of the time slot of terminal own by the resource of maximization use MS or any terminal, has realized the estimation of the power of base station frequently to the neighbour; The present invention passes through the calculating of current terminal apart from the distance of neighbour's frequency base station, and according to the scope of distance with to neighbour's estimation of base station power frequently, distance mode is selected in choosing accordingly and rational access power carries out faster and more rational access to target BS; In addition, in the environment in remote rural area and mountain area, may be apart from the very near base station of terminal because block or multipath effect causes the poor signal of incoming terminal, enlarge the corresponding adjacent search window of base station monitoring frequently by the present invention, can increase the probability of terminal handover success and can realize finishing the covering of same range as with the base station number of minimum.
Description of drawings
The switched system structural representation that Fig. 1 normally switches for the cdma system terminal under the TDD in the prior art;
Fig. 2 is the structural representation of switched system of the present invention;
Fig. 3 is the schematic flow sheet of changing method of the present invention;
Fig. 4 is the block diagram of synchronous searching scope when of the present invention for the SCDMA system terminal adopts;
Fig. 5 is the processing sequential schematic diagram of the skyborne delay of signal and emission in the SCDMA system.
Embodiment
Below in conjunction with accompanying drawing, concrete enforcement of the present invention is described in further detail.
Concrete set forth the present invention before, below earlier the direct-cut operation flow process of cdma system is done simple a description.Wherein, the condition that switches is: between (be different CDMA operator between) between disjoint base station (BS) set, the different Active Set, between the different frequency range, between the different frequency or between the different frame biasings.The groundwork flow process is as follows:
Step 1:BS communicates by letter on original Traffic Channel with portable terminal (MS); When the decision of the mobile switching centre of BS allows MS different Active Set or the identical Active Set on the different frequency are searched on to same frequency, send and have the isoparametric message of Active Set power (being the candidate frequency search (CFS) request) and give MS;
The switch control unit of step 2:MS calculates search time according to search parameter, and to BS make sound should;
After step 3:BS received the response of MS, the decision of the mobile switching centre of BS allowed MS begin search (can be the single search, also can be the cycle search), sends the message that starts search then;
After step 4:MS received the message that starts search, the switch control unit of MS was preserved the configuration of existing Traffic Channel, stopped former Traffic Channel operation; And adjust on the pairing parameter of new Traffic Channel, begin to search for new pilot tone;
Step 5:MS comes back on the original Traffic Channel, and recover original configuration and communicate by letter, and to BS search report result;
Step 6:BS recovers the communicating by letter on original Traffic Channel with MS, receives the Search Results report of MS; The mobile switching centre of BS allows MS switch on the new Traffic Channel according to Search Results decision, and sets up new Traffic Channel and begin to send; BS begins to switch by original Traffic Channel notice MS then;
After step 7:MS receives switch indicating information, preserve original traffic channel configuration, stop using original Traffic Channel, the MS trial is set up with BS with new Traffic Channel and newly is connected; If MS switches trial and success, just on new Traffic Channel, communicate by letter, and send handoff completion message to BS by new Traffic Channel; If switch not success, then return to original Traffic Channel communication;
Step 8:BS receives handoff completion message, discharges original Traffic Channel, continues to communicate by letter with MS with new Traffic Channel.Wherein, new Traffic Channel can be the Traffic Channel between the current area different B S, also can be the Traffic Channel between the different frame biasing sub-district.
Be example with the SCDMA system below, in conjunction with improvement of the present invention and optimization, and according to the feature of SCDMA system and the characteristics of switching, the present invention is further detailed explanation in conjunction with the accompanying drawings.
Be illustrated in figure 2 as the structural representation of switched system of the present invention, switched system of the present invention comprises MDM and the MCU that has switch control unit respectively, the switch control unit of wherein said MDM comprise the monitor adjacent frequency module, with described monitor adjacent frequency module carry out information interaction power estimation module, and carry out information interaction with described monitor adjacent frequency module, be used to calculate the distance calculation module of current terminal apart from the distance of neighbour's frequency base station; The switch control unit of described MCU comprises adjacent base station monitoring result's the decision-making module frequently that receives described monitor adjacent frequency module transmission.
Wherein, described monitor adjacent frequency module is searched for and is monitored in the base station frequently the neighbour in the synchronous searching scope that described MDM determines; And described synchronous searching scope is determined according to the ultimate range of the base station of described remote switching support search by described MDM.Described decision-making module is used for according to described adjacent base station monitoring result frequently and current terminal selecting the target BS that switches apart from neighbour's distance of base station frequently.Described power estimation module is used for according to described synchronous searching scope, and the adjacent pilot channel of base station frequently that signal is dropped in the described synchronous searching scope carries out the power estimation; And described power estimation module also is used to distinguish the different operating state of current terminal, and according to the deviation of synchronous points and the concrete scope of search thereof, under the prerequisite that the length that guarantees the terminal receiving slot remains unchanged, the receiving slot of terminal is adjusted.
Fig. 3 is the schematic flow sheet of changing method of the present invention, as shown in Figure 3, realizes that in the SCDMA system the remote method of switching comprises the steps:
Step 1: the MDM of terminal judges whether terminal supports remote switching, if support that then execution in step 2; Otherwise, carry out existing switching flow.
Step 2:MDM is according to the remote ultimate range of switching the base station of supporting search, and wherein said ultimate range can be carried out suitable configuration by webmaster according to local networks, determines the remote required synchronous searching scope of switching.The concrete computing formula of synchronous searching scope is:
Wherein C is electromagnetic transmission rate, and promptly the light velocity is 3 * 10
5Km/s; 2.4414us be the chip duration of SCDMA system.For example, suppose in handoff procedure, to require to support the maximum base station signal that can search in the 58.6km scope that then the synchronous searching scope of terminal need be set to
The monitor adjacent frequency module of step 3:MDM is searched for and is monitored in the base station frequently the neighbour in described synchronous searching scope.
Wherein, because the increase of synchronous searching scope, the time that MDM carries out related calculation also will increase, thereby has caused that MDM receives the variation of handling time slot, therefore before the monitor adjacent frequency module of MDM is searched for neighbour's frequency base station and monitored, needs to carry out following steps earlier:
Step a:MDM receives the processing time slot to it and compensates according to the synchronous searching scope.Concrete set-up procedure is:
Step a1:MDM determines that the synchronous searching scope is with respect to the recruitment of not supporting remote switching terminal;
Then, step a2:MDM, adjusts terminal and receives the length of handling time slot, so that search for farther down-going synchronous apart from the base station under the prerequisite that the overall time slot that guarantees the terminal time slot remains unchanged according to described recruitment;
At last, step a3:MDM receives the processing time slot to it and compensates according to terminal is received the adjustment amount of handling slot length.
Same because the increase of synchronous searching scope, in order accurately to estimate the adjacent synchronizing symbol power of the pilot channel of base station frequently in the synchronous searching scope, the power estimation module of MDM need be adjusted the position and the time point of its rated output, therefore the power estimation module of execution in step b:MDM is according to the synchronous searching scope, and the adjacent pilot channel of base station frequently that signal is dropped in the synchronous searching scope carries out the power estimation.Concrete steps are:
At first, step b1:MDM distinguishes the different operating state of current terminal, and the data of the symbol lengths of M before the synchronizing symbol are carried out DC processing; Wherein, M is the positive integer between 2～4; If M is greater than 4, then effectively the information digit rate can reduce; If M is less than 2, then power is estimated inaccurate.In the present embodiment for the data of preceding four symbol lengths of synchronizing symbol are carried out DC processing;
Then, step b2:MDM obtains another synchronous points position P2 in the length that the synchronous P1 place, synchronous points position of terminal and current base station increases N symbol;
Wherein, according to the requirement of SCDMA system and the accuracy of rated output, N is the positive integer more than or equal to 1; Perhaps the length of N symbol is the mean value of the length of N symbol.In the present embodiment for increasing the length of 1 symbol;
At last, the power estimation module of step b3:MDM is a benchmark with another synchronous points position P2, estimate that (M+N) of synchronizing symbol power individual or the individual symbol of the [(M+1)+N] is equivalent to the power of synchronizing symbol, and with this adjacent power of base station frequently that receives as terminal.In the present embodiment, estimate that the power of second or the 3rd symbol of synchronizing symbol is equivalent to the power of synchronizing symbol.
Be illustrated in figure 4 as the block diagram that the SCDMA system terminal adopts synchronous searching scope when of the present invention, the adjacent supervision stage of base station frequently in handoff procedure, the distance of supposing current base station and terminal is Xkm, the reception time started that terminal is carried out before the monitor adjacent frequency is T0, to carry out the time that begins to receive of the frame of monitor adjacent frequency be T=T0+ (21.9726-X)/C to terminal so, wherein C is the light velocity, and then Zui Da time difference is Δ T=T-T0=50chip=122.07us.The MDM of terminal begins to receive data from the T time, takes advantage of the related operation that adds in the synchronous searching scope, and monitor adjacent frequency finishes the back, and to recover time of reception be T0, its effect as shown in Figure 4.Fig. 4 cathetus is represented the terminal searching window, chain-dotted line can search the part that far and near all base stations should be added when indicating to guarantee to search for adjacent frequency base station, the adjacent distance range of base station frequently that the adjacent distance range of base station frequently that search window before the corresponding change of the distance range that straight line marks above can be swept to, the corresponding search window that increases of the distance range that chain-dotted line marks above can be swept to.5 figure represent the distance of terminal and current base station respectively among the figure, wherein 5 more special points are 0km, 21.9726km, 23.4375km, 43.9452km, 58.6km as can be seen from the figure, terminal is different with the distance of base station, guarantee to search adjacent frequency and just need carry out the adjustment of time of reception, but the width of search window remains unchanged, and all is 80 chip, has Duoed 20 chip than original search window.
The distance calculation module of execution in step 4:MDM is calculated the distance of current terminal apart from neighbour's frequency base station according to the adjacent base station monitoring result frequently of the monitor adjacent frequency module of MDM afterwards.
The decision-making module of step 5: terminal MCU apart from neighbour's distance of base station frequently, is selected the target BS that switches according to the adjacent base station monitoring result frequently of the monitor adjacent frequency module of MDM and current terminal; Decision mechanism that it is main and prior art similar do not repeat them here.
Step 6:MDM selects corresponding distance mode and access parameter to insert to target BS according to the distance of current terminal and target BS.
In the present invention, described access parameter comprises selection, the selection of far and near distance pattern and the selection of transmitting power etc. of some launch time at least, wherein:
Launch time, the selection of point was that the terminal signaling that target BS is received falls into the high order end of target BS search window, thereby made the coverage of base station reach maximum.
The selection of far and near distance pattern is: if the distance of current terminal distance objective base station is then selected closely access module less than 23.4 kms; If the distance of current terminal distance objective base station is then selected remote access module greater than 35.1 kms; If the distance of current terminal distance objective base station between 23.4 kms and 35.1 kms, is then selected remote access module or a kind of in the access module closely.
The selection of transmitting power is to make its interference to system reach minimum; Wherein, according to the identical principle of SCDMA system up-downgoing attenuation, MDM can attempt the transmitting power that access sequence is determined terminal according to terminal on the basis of the power of the target BS of its calculating.
Wherein, step 6 is specially:
1) MDM is according to the distance of current terminal and target BS, selects corresponding distance mode (and be earlier remote access module in the different prior art, after closely access module).Simultaneously,
2) MDM arrives the time delay of current terminal according to the distance estimations target BS downstream signal of current terminal and target BS, and then determines corresponding launch time of point.
Be illustrated in figure 5 as the processing sequential schematic diagram of the skyborne delay of signal and emission in the SCDMA system.When the distance of terminal and base station is 0km, the transmitting-receiving time unifying of terminal and base station; When the distance of terminal and base station was Xkm, the downstream signal incoming terminal of base station exists and postpones PT, and was same, and the upward signal of terminal will shift to an earlier date same delay time PT emission, could guarantee that the base station just in time receives; So the distance of base station and terminal is X=(PT1-PT) * C/2, wherein C is the light velocity, and PT1 is for inserting default value, and PT is the current delay time.Therefore, according to X=(PT1-PT) * C/2, when know current terminal and target BS apart from the time, can estimate the time delay that the target BS downstream signal arrives current terminal; Simultaneously to shift to an earlier date same delay time emission and could guarantee that the base station just in time receives, and then can determine corresponding launch time of point according to the upward signal of terminal.
3) MDM initiates to divide frame to insert or presumptuously frame access according to the definite transmitting power of the power of the target BS of its power estimation module calculating to target BS.
In addition, in the described access procedure of step 6, on the synchronous basis of current terminal and target BS, also comprise:
1) power estimation module of terminal MDM is distinguished the different operating state of current terminal, and according to the deviation of synchronous points and the concrete scope of search thereof, under the prerequisite that the length that guarantees the terminal receiving slot remains unchanged, the receiving slot of terminal is adjusted; And
2) MDM determines the data that receive are carried out the starting position of the actual demodulation point of corresponding demodulation, is specially:
At first, in order to consider worst situation, MDM estimates synchronous points when the T1 place, position on the right side of described synchronous searching scope, the difference T2 of the position of synchronous points and the starting position of real data;
Afterwards, MDM determines the starting position of actual demodulation point according to T1 and T2; The starting position that is actual demodulation point is the difference that the length of synchronizing symbol deducts T1 and T2.
Cdma system terminal under the existing TDD is that 30chip opens reception before the prediction synchronous points, that is: find after the switching synchronous base station and current terminal distance can not with keep synchronous base station at present and differ the distance range (be 21.9km) corresponding above 30chip.In order to make full use of the existing systems resource, the present invention enlarges the synchronous searching scope, increases the distance of two base stations of switching, the number of base stations that can select to switch is increased, the probability of handover success increases, alternative increasing, and the travelling performance of terminal brings lifting thereupon.For the terminal of 400M, the present invention can determine the distance of current terminal apart from synchronising base station according to PT time (as shown in Figure 5) and distance mode simultaneously; The monitor adjacent frequency stage according to monitoring the adjacent skew of synchronous head frequently the time, can determine apart from the distance of target frequency and current terminal synchronizes base station,, can draw the general distance of terminal apart from target BS according to these two distances, thereby determine the distance mode of access phase, save turn-on time.
Should be pointed out that this paper is described in detail in the concrete enforcement of SCDMA system the present invention with top, but it is preferred embodiment of the present invention only, is not to be used to limit protection scope of the present invention, the present invention also can be used for the cdma system under other TDD.It will be apparent to those skilled in the art that and can also make some improvements and modifications under the prerequisite that does not break away from the principle of the invention, these improvements and modifications also should be considered as protection scope of the present invention.
Claims (10)
1. the cdma system terminal under the TDD realizes the remote changing method that switches, and it is characterized in that, comprises the steps:
Step 1: the modem module of terminal judges whether described terminal supports remote switching, if support that then execution in step 2; Otherwise, carry out existing switching flow;
Step 2: described modem module is determined the synchronous searching scope that described remote switching is required according to the ultimate range of the base station of described remote switching support search;
Step 3: described modem module is searched for and is monitored in the base station frequently the neighbour in described synchronous searching scope;
Before neighbour's frequency base station being searched for and monitored, need to carry out following steps a and step b earlier:
Step a: described modem module receives the processing time slot to it and compensates according to described synchronous searching scope;
Step b: described modem module is according to described synchronous searching scope, and the adjacent pilot channel of base station frequently that signal is dropped in the described synchronous searching scope carries out the power estimation;
Step 4: described modem module calculates the distance of current terminal apart from neighbour's frequency base station according to neighbour's frequency base station monitoring result;
Step 5: little processing and control element (PCE) of terminal apart from neighbour's distance of base station frequently, is selected the target BS that switches according to described adjacent base station monitoring result frequently and current terminal;
Step 6: described modem module selects corresponding distance mode and access parameter to insert to target BS according to the distance of current terminal and target BS.
2. changing method according to claim 1 is characterized in that, in described step 2, the ultimate range of the base station of described remote switching support search is configured according to described system by webmaster.
3. changing method according to claim 1 is characterized in that, described step a is specially:
Step a1: described modem module determines that described synchronous searching scope is with respect to the recruitment of not supporting remote switching terminal;
Step a2: described modem module, is adjusted terminal and is received the length of handling time slot under the prerequisite that the overall time slot that guarantees the terminal time slot remains unchanged according to described recruitment;
Step a3: described modem module receives the processing time slot to it and compensates according to terminal is received the adjustment amount of handling slot length.
4. changing method according to claim 1 is characterized in that, described step b is specially:
Step b1: described modem module is distinguished the different operating state of current terminal, and the data of the symbol lengths of M before the synchronizing symbol are carried out DC processing;
Step b2: described modem module increases the length of N symbol in the first synchronous synchronous points position of terminal and current base station, obtain the second synchronous points position;
Step b3: described modem module is a benchmark with the described second synchronous points position, estimates that the M+N power individual or (M+1)+N symbol of synchronizing symbol is equivalent to the power of synchronizing symbol, and with this adjacent power of base station frequently that receives as terminal;
Described M is the positive integer between 2～4;
According to the requirement of described system and the accuracy of rated output, described N is the positive integer more than or equal to 1; The length of perhaps described N symbol is the mean value of the length of N symbol.
5. changing method according to claim 1 is characterized in that, in described step 6, described access parameter comprises selection, the selection of far and near distance pattern and the selection of transmitting power of some launch time at least, wherein:
The selection of launch time point is the high order end that terminal signaling that target BS is received falls into the target BS search window;
The selection of far and near distance pattern is: if the distance of current terminal distance objective base station is then selected closely access module less than 23.4 kms; If the distance of current terminal distance objective base station is then selected remote access module greater than 35.1 kms; If the distance of current terminal distance objective base station between 23.4 kms and 35.1 kms, is then selected remote access module or a kind of in the access module closely;
The selection of transmitting power is to make its interference to system reach minimum; Wherein, described modem module is attempted the transmitting power that access sequence is determined terminal according to terminal on the basis of the power of the target BS of its calculating.
6. changing method according to claim 5 is characterized in that, described step 6 is specially:
Described modem module is selected corresponding distance mode according to the distance of current terminal and target BS; Simultaneously,
Described modem module arrives the time delay of current terminal according to the distance estimations target BS downstream signal of current terminal and target BS, and then determines corresponding launch time of point; Afterwards,
The transmitting power that described modem module is determined according to the power of the target BS of its calculating initiates to divide frame access or overstepping one's bounds frame to insert to target BS.
7. changing method according to claim 1 is characterized in that, in the described access procedure of described step 6, on the synchronous basis of current terminal and target BS, also comprises:
Described modem module is distinguished the different operating state of current terminal, and according to the deviation of synchronous points and the concrete scope of search thereof, under the prerequisite that the length that guarantees the terminal receiving slot remains unchanged, the receiving slot of terminal is adjusted; And
Described modem module determines the data that receive are carried out the starting position of the actual demodulation point of corresponding demodulation.
8. changing method according to claim 7 is characterized in that, the starting position of described definite actual demodulation point is specially:
Steps A: described modem module is estimated synchronous points when the position on the right side of described synchronous searching scope, the difference of the position of synchronous points and the starting position of real data;
Step B: described modem module is determined the starting position of described actual demodulation point according to the position and the described difference on the described right side; The starting position that is described actual demodulation point is that the length of described synchronizing symbol deducts the position on the described right side and the difference of described difference.
9. the cdma system terminal under the TDD realizes the remote switched system that switches, comprise the modem module and the little processing and control element (PCE) that have switch control unit respectively, the switch control unit of wherein said modem module comprises that the monitor adjacent frequency module reaches the power estimation module of carrying out information interaction with described monitor adjacent frequency module, the switch control unit of described little processing and control element (PCE) comprises adjacent base station monitoring result's the decision-making module frequently that receives described monitor adjacent frequency module transmission, it is characterized in that the switch control unit of described modem module also comprises:
Carry out the distance calculation module of information interaction with described monitor adjacent frequency module, be used to calculate current terminal apart from neighbour's distance of base station frequently;
Wherein, described monitor adjacent frequency module is searched for and is monitored in the base station frequently the neighbour in the synchronous searching scope that described modem module is determined; Wherein, described synchronous searching scope is determined according to the ultimate range of the base station of described remote switching support search by described modem module.
10. switched system according to claim 9 is characterized in that,
Described decision-making module is used for according to described adjacent base station monitoring result frequently and current terminal selecting the target BS that switches apart from neighbour's distance of base station frequently;
Described power estimation module is used for according to described synchronous searching scope, and the adjacent pilot channel of base station frequently that signal is dropped in the described synchronous searching scope carries out the power estimation; And also be used to distinguish the different operating state of current terminal, and, under the prerequisite that the length that guarantees the terminal receiving slot remains unchanged, the receiving slot of terminal adjusted according to the deviation of synchronous points and the concrete scope of search thereof.
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| CN101193425B true CN101193425B (en) | 2011-03-16 |
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| EP2537393A1 (en) * | 2010-02-15 | 2012-12-26 | Nokia Siemens Networks Oy | Base station aided synchronization |
| JP6362331B2 (en) * | 2014-01-07 | 2018-07-25 | 三菱電機株式会社 | Base station and radio communication system |
| CN104244178B (en) * | 2014-09-01 | 2016-08-24 | 努比亚技术有限公司 | Mobile terminal based on mobile device management MDM recovers method and system thereof |
| CN104869555B (en) * | 2015-04-23 | 2018-09-04 | 新华三技术有限公司 | Processing method and processing device based on terminal roaming |
| WO2020042017A1 (en) * | 2018-08-29 | 2020-03-05 | 深圳市大疆创新科技有限公司 | Tdd communication method and device |
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| WO2005109925A1 (en) * | 2004-05-07 | 2005-11-17 | Telefonaktiebolaget Lm Ericsson (Publ) | System and method for selecting a point-to-point or point-to-multipoint transmission mode |
| US20060256745A1 (en) * | 2002-04-05 | 2006-11-16 | Interdigital Technology Corporation | HS-DSCH inter-node B cell change |
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| CN1299569A (en) * | 1998-07-06 | 2001-06-13 | 株式会社洛克斯 | Mobile terminal, locator, system using the same, and method of locating mobile terminal |
| CN1430340A (en) * | 2001-12-29 | 2003-07-16 | 联想(北京)有限公司 | Radio communication system combining with long and short distance technology and its realizing method |
| US20060256745A1 (en) * | 2002-04-05 | 2006-11-16 | Interdigital Technology Corporation | HS-DSCH inter-node B cell change |
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