Make mobile unit change the method for serving BS
Technical field
The present invention relates to a kind of method of changing serving BS, particularly a kind of method that makes mobile unit change serving BS.
Background technology
Because the development of wireless communication system technologies, radio communication and personal mobile communication have become indispensable some in modern's daily life every day.Global system for mobile communications (Global Systemfor Mobile communication, GSM) be the system that the maximum people in present Taiwan use, because popularizing of this kind gsm mobile telephone, make interpersonal communication become convenient and simple, so long as the scope that signal of communication is contained, can talk with other people anywhere or anytime, not be subjected to the restriction in time place.
See also Fig. 1.The schematic diagram that shows a wireless communication system 6 among Fig. 1.Be to include a plurality of base station area (Cell) (not being shown among Fig. 1) that communication service is provided by a base station (Base Station) respectively in the wireless communication system 6, because these a plurality of base station area adjoin each other with the favous framework of class usually, so this type of wireless communication system also is called as cellular wireless communication system often.For the purpose of simplifying the description, in Fig. 1, comprise a base station area 22, and base station area 30, wherein base station area 22 is to provide communication service by a base station 24, and base station area 30 is to provide communication service by a base station 28.All include in the service range of base station area 22 and base station area 30 mobile unit (Mobile Subscriber, MS) 26, mobile unit 26 is used for transmitting and receives wireless communication signals and communicates with each other to be connected network with the base station.Be in simultaneously in the service range of base station area 22 and base station area 30 owing to mobile unit 26 herein; mobile unit 26 is the signal of transceiver base station 24 and base station 28 simultaneously; so; mobile unit 26 can be chosen signal strength signal intensity is stronger in base station 24 and the base station 28 base station usually as serving BS zone (Serving Cell); to login (camp on) this serving BS zone and to start ensuing work; and move and when causing in the base station 28 signal strength signal intensity to arrive certain depth changing when mobile unit 26; the affirmation action that mobile unit 26 can be logined; base station area selects (cellselection) process need use C1 and two parameters of C2 are judged; C1 is loss of transmission paths door (Path loss criterion); C2 is honeycomb gravity treatment door (Cell reselection criterion); in the prior art; serving BS is for mobile unit 26; have positive C1 value and the highest C2 value and be considered to the serving BS of the best; therefore often when mobile unit detects higher C2; just begin to change serving BS, please refer to Fig. 2.Fig. 2 changes the flow chart of the method for serving BS for original technology makes mobile unit.As described above, mobile unit must select a base station that signal strength signal intensity is strong and the most suitable as the base station of linking up.The signal of broadcasting control channel is sent in the base station, makes mobile unit decision C1 and two parameters of C2, and in order to judge the program of selecting base station area, as ETSI 05.08 defined, C1 is defined as follows:
C1=(A Max (B, 0)); Wherein
A=RLA_C RXLEV_ACCESS_MIN;
RLA_C is the average power of the carrier wave of signal;
But RXLEV_ACCESS_MIN is the minimum signal strength of a mobile unit connected system;
B=MS_TXPWR_MAX_CCH P;
MS_TXPWR_MAX_CCH is the maximum of power control not also on the broadcasting control channel;
P is the peak power output of this mobile unit;
If the C1 value of certain base station area, represents that this base station area is fit to mobile unit and logins greater than zero, and the maximum base station area of C1 value will be chosen as the base station area that mobile unit is logined.If mobile unit is in mobile status (in the process that moves, the parameters C 1 of detected base station area will change), or selected before base station area refusal then must utilize this parameter of C2 when accepting communication and waiting other reason again, judges selected base station area.C2 is defined as follows:
C2=C1+CELL_RESELECTION_OFFSET TEMPORARYOFFSET*H(PENALTY_TIME T);
Equal PENALTY_TIME<11111
Wherein, for non-serving base station zone
H(x)=0?for?x<0
=1?for?x≥0;
For just in the serving base station zone
H(x)=0;
After mobile unit had been logined a serving BS, at set intervals, mobile unit can detect the signal magnitude that broadcasting control channel is sent in a plurality of base station contiguous in the public land mobile net network, and upgrades one group of C1 and C2 again.The step 100 of Fig. 2 is carried out this action, upgrades the value of C1 and C2.Step 110, judge contiguous base station area whether with serving BS belong to the identical band of position (LocalArea, LA).If be judged as "Yes", then in step 120, judge the parameters C 2 of neighbor base station corresponding to this mobile unit by step 110
NWhether continue in a scheduled time slot greater than the parameters C 2 of this serving BS corresponding to this mobile unit
SIf be judged as "No", then in step 130, judge the parameters C 2 of this neighbor base station corresponding to this mobile unit by step 110
NContinue a scheduled time slot greater than the parameters C 2 of this serving BS corresponding to this mobile unit
SOne first threshold value CRH (Broadcasted hysteresisvalue) just judges C2
N>C2
SWhether+CRH sets up.If step 120 or step 130 are judged as "Yes", then enter step 140 and carry out the gravity treatment base station area.If step 120 or step 130 are judged as "No", then do not carry out the gravity treatment base station area, and wait for the renewal of C1 and C2 in step 100.Method flow 700 as shown in Figure 3, it comprises step 110, step 120 and step 130, and this group of methods flow process is called base station decision flow process (better cell decision).。
Please refer to Fig. 3.Fig. 3 is the schematic diagram for a wireless communication system 50.Mobile unit 26 is among base station area A, base station area B and the base station area C simultaneously.If, the user of mobile unit 26 is office workers that work in office, and just his residing office is the intersection of three base station area A, B, C in as figure, originally mobile unit 26 is logined to base station A, but after the user moved a little, mobile unit 26 must be carried out the base station area gravity treatment and select base station B to do and logined.Very long a period of time was arranged in one day, and he can move in this zonule of office everywhere, and therefore, mobile unit 26 can be carried out base station area gravity treatment several times, and such process can consume many power.In fact, for such situation, mobile unit 26 can be changed the base station of being logined always, because fixedly login one of them base station in such zonule always, just can obtain good communication quality, nor can cause the waste of power.Yet the method with known base station zone gravity treatment can't solve this problem.
Summary of the invention
Disclose the method that a kind of mobile unit is changed serving BS according to the present invention, this mobile unit receives the broadcast singal of a serving BS and a neighbor base station, and this method comprises the following step: (a) obtain this serving BS corresponding to one the one C2 parameter of this mobile unit and one the one C1 parameter and this neighbor base station one the 2nd C2 parameter corresponding to this mobile unit; (b) a C1 parameter and a default value are compared; (c) when a C1 parameter during less than this default value, a second area sign indicating number of a first area sign indicating number of this neighbor base station and this serving BS relatively; (d) when this first area sign indicating number is identical with this second area sign indicating number, relatively the 2nd a C2 parameter and a C2 parameter, when the 2nd C2 parameter greater than a C2 parameter and when continuing one first scheduled time slot, the serving BS of changing this mobile unit is this neighbor base station; And (e) when this first area sign indicating number and this second area sign indicating number are inequality, relatively the 2nd C2 parameter and one first parameter, when the 2nd C2 parameter greater than this first parameter and when continuing one second scheduled time slot, the serving BS of changing this mobile unit is this neighbor base station, this first parameter be a C2 parameter and one first threshold value and.
Disclose a kind of mobile unit according to the present invention, this mobile unit receives the wireless signal of a serving BS and a neighbor base station, this mobile unit comprises: a parameter acquisition unit, in order to obtain one the one C1 parameter, one the one C2 parameter and one the 2nd C2 parameter, the one a C1 parameter and a C2 parameter are corresponding to this serving BS, and the 2nd C2 parameter is to should neighbor base station; One switches base station unit, in order to base station shifting; One judging unit, be in order to relatively a C1 parameter and one first predetermined value, when a C1 parameter less than this first predetermined value, carry out base station decision flow process, when a C1 parameter greater than this first predetermined value, this judging unit continues in one the 3rd scheduled time slot relatively the 2nd C2 parameter and one second parameter, when the 2nd C2 parameter continues in the 3rd scheduled time slot greater than this second parameter, send a signal to this base station shifting unit, make this mobile unit switch communication base station by this serving BS to this neighbor base station, this second parameter be a C2 parameter and one second threshold value with.
Description of drawings
The schematic diagram that shows a wireless communication system among Fig. 1.
Fig. 2 is the schematic diagram of a wireless communication system.
Fig. 3 is a kind of flow chart that makes mobile unit change the method for serving BS of the present invention.
Fig. 4 is a kind of flow chart that makes mobile unit change the method for serving BS of another embodiment of the present invention.
Fig. 5 is a kind of flow chart that makes mobile unit change the method for serving BS of another embodiment of the present invention.
Fig. 6 is the schematic diagram of a kind of mobile unit of the present invention.
The reference numeral explanation
22,30 base station area
24,28 base stations
6,50 wireless communication systems, 10,26 mobile units
12 parameter acquisition units, 14 base station shifting unit
16 judging units
Embodiment
Please refer to Fig. 4.Fig. 4 is a kind of flow chart that makes mobile unit change the method for serving BS for the embodiment of the invention.In order to solve the problem of previous unnecessary base station area gravity treatment, and reduce base station area gravity treatment number of times to reduce power consumption, the present invention has changed the judgement requirement to C1 and C2 in the process of base station area gravity treatment, and has adjusted the judgement flow process.The step 200 of Fig. 4 is upgraded the value of C1 and C2.In step 210, judge serving BS corresponding to the C1s of this mobile unit whether greater than a default value C1
ThresholdIn step 210, be judged as "Yes" and then judge the parameters C 2 of a neighbor base station corresponding to this mobile unit in step 220
NWhether continue a scheduled time slot greater than the parameters C 2 of serving BS corresponding to this mobile unit
SOne adds a threshold value C2
Inertia, in other words, just judge C2
N>C2
S+ C2
InertiaWhether set up, that is want real the reaching of signal of neighbor base station, mobile unit just to determine to judge the change serving BS, otherwise can keep original base station.If in step 210 judged result is "No", then carry out a succession of step in the flow process 700.When the judged result of flow process 700 or step 220 is a "Yes", then carry out the gravity treatment base station area in step 230.When the judged result of flow process 700 or step 220 is a "No", then do not carry out the gravity treatment base station area, and wait for the renewal of C1 and C2 in step 200.
Please refer to Fig. 5.Fig. 5 is a kind of flow chart that makes mobile unit change the method for serving BS for another embodiment of the present invention.Step 300 is upgraded the value of C1 and C2.Step 310 judge serving BS corresponding to the C1s of this mobile unit whether greater than a default value C1
ThresholdIn step 310, be judged as "Yes" and then judge C2 in step 320
N>C2
S+ C2
InertiaWhether continue a scheduled time slot and set up, wherein C2
NBe the parameter of neighbor base station corresponding to this mobile unit, C2
SBe the parameter of serving BS corresponding to this mobile unit, C2
InertiaIt is a threshold value.If in step 310 judged result is "No", then carry out flow process 700_1, flow process 700_1 is a succession of step of the method flow 700 among Fig. 3.When the judged result of flow process 700_1 or step 320 is a "Yes", then carry out the gravity treatment base station area entering step 330.When the judged result of flow process 700 is a "No", then do not carry out the gravity treatment base station area, and wait for the renewal of C1 and C2 in step 300.
Be different from Fig. 4, working as step 320 judged result in Fig. 5 is "No", then carries out flow process 700_2, and flow process 700_2 is a succession of step of the method flow 700 among Fig. 3.When the judged result of flow process 700_2 is a "No", then enter the renewal that step 300 is waited for C1 and C2.If the judged result of flow process 700_2 is a "Yes", the condition of the number of delivering a letter failure under then in step 340, changing.This so-called pass down failure be meant when mobile unit by the authentication of various identifications, also finish the affirmation of gravity treatment base station area simultaneously after because other condition does not meet, signal can't be passed to mobile unit in the base station, the number of delivering a letter is failed under then judging.Under after the number of delivering a letter changes, continue to wait for the renewal of C1 and C2 parameter in step 300.
Please refer to Fig. 6.Fig. 6 is the schematic diagram of a kind of mobile unit 10 of the present invention.Mobile unit 10 receives the wireless signal of a serving BS and a neighbor base station.This mobile unit comprises a parameter acquisition unit 12, and switches a base station unit 14 and a judging unit 16.Parameter acquisition unit 12 is in order to obtain one the one C1 parameter, one the one C2 parameters C 2s and one the 2nd C2 parameters C 2
N, a C1 parameter and a C2 parameters C 2s are corresponding to this serving BS, the 2nd C2 parameters C 2
NBe to should neighbor base station.Base station shifting unit 14 is in order to base station shifting.Judging unit 16 is in order to relatively a C1 parameter and one first predetermined value, when a C1 parameter less than this first predetermined value, carry out base station decision flow process, when a C1 parameter greater than this first predetermined value, this judging unit is the 2nd C2 parameters C 2 relatively
NWith one second parameter, when the 2nd C2 parameters C 2
NGreater than this second parameter, send a signal to this base station shifting unit, make this mobile unit switch communication base station by this serving BS to this neighbor base station, and this second parameter is a C2 parameters C 2
NSummation with one second threshold value.Wherein, decision flow process in this base station is as follows for the flow process 700 of Fig. 2: when (a) judging a C1 parameter less than this default value, relatively (Location Area Code is LAC) with a second area sign indicating number of this serving BS for a first area sign indicating number of this neighbor base station; (b) when this first area sign indicating number is identical with this second area sign indicating number, relatively the 2nd a C2 parameter and a C2 parameter, when the 2nd C2 parameter greater than a C2 parameter and when continuing one first scheduled time slot, send a signal to this base station shifting unit; And (c) when this first area sign indicating number and this second area sign indicating number are inequality, relatively the 2nd C2 parameter and one first parameter, when the 2nd C2 parameter greater than this first parameter and when continuing one second scheduled time slot, send a signal to this base station shifting unit, this first parameter be a C2 parameter and one first threshold value and.
In the determination methods of base station area gravity treatment formerly, when a mobile unit frequent moving in a zonule, and this zonule is when being positioned at the position, boundary of many base station area again, this mobile unit can constantly be carried out the base station area gravity treatment, and repeatedly the base station area gravity treatment of Shuoing has consumed many power virtually.Yet the action of these base station area gravity treatments is being unnecessary in such cases, and this mobile unit only need select a fixing base station to login, even move around in this zone, still can obtain good communication quality.Therefore, these are unnecessary power dissipation because of power that the base station area gravity treatment of repeatedly counting consumes.Determination methods compared to previous base station area gravity treatment, of the present invention making in the method that mobile unit changes serving BS, in the process of base station area gravity treatment, changed the Rule of judgment of C1 and C2, and adjust and judge flow process, therefore, when mobile unit when judging whether to change serving BS, tighter condition restriction is only arranged, avoid excessively changing in unnecessary situation as previously mentioned the problem of serving BS, had the advantage of saving power.
The above only is preferred embodiment of the present invention, and all equalizations of being done according to the present patent application claim change and modify, and all should belong to the covering scope of patent of the present invention.