CN100396144C - Method of cross-region switching in mobile communication system - Google Patents
Method of cross-region switching in mobile communication system Download PDFInfo
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- CN100396144C CN100396144C CNB031488935A CN03148893A CN100396144C CN 100396144 C CN100396144 C CN 100396144C CN B031488935 A CNB031488935 A CN B031488935A CN 03148893 A CN03148893 A CN 03148893A CN 100396144 C CN100396144 C CN 100396144C
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Abstract
The present invention discloses a mobile station zone spanning switching method of mobile communication systems, which causes the users of mobile stations to still obtain good speech quality under the condition of fast movement. The mobile station zone spanning switching method of mobile communication systems mainly comprises the following steps: A, the moving speed of mobile stations moving along linear roads is calculated; B, the mobile stations are judged whether the mobile stations are in a fast moving state, if the mobile stations are in a fast moving state, step C is carried out, otherwise, step D is carried out; C, the linear relevant priority of the linear relevant sub-zones of the linear roads is enhanced, and step E is carried out; D, the linear relevant priority of the linear relevant sub-zones of all of the linear roads is canceled, and step E is carried out; E, the corresponding total switching priority value of candidate sub-zones which can be switched by the mobile stations is calculated, the candidate sub-zones are ordered according to the magnitude of the total switching priority value; F, the sub-zone with the maximal total switching priority is switched according to the ordering result.
Description
Technical Field
The present invention relates to a mobile communication method, and more particularly, to a handover method for a mobile station in a mobile communication system.
Background
With the development of mobile communication technology, more and more people have mobile stations such as mobile phones and enjoy the convenience of mobile communication services. However, so far, there still exist some problems in mobile communication services, for example, when a user of a mobile station is talking, if the user rapidly crosses different cells for many times, the network side control device needs to perform handover for many times to ensure the continuation of the talking, in which case the talking quality of the user may be affected.
For example, referring to fig. 1, a mobile station moving at a high speed from north to south along the road 10 in the figure frequently switches among the cells 40, 30 and 20 in the process. In this case, two problems are easily caused, one is that between two handovers, the network usually requires the mobile station to keep the handover stable, and even if there is no such requirement, due to the fast moving speed of the mobile station, the handover is easily caused to be untimely, and the call drop is easily caused; secondly, even if the switching can be completed, the voice is interrupted due to the switching, which causes the reduction of the communication quality.
Therefore, how to ensure good call quality when the mobile station moves rapidly and avoid voice intermittence and even call drop is a problem which needs to be solved urgently, and many communication companies are beginning to research the problem and successively put forward some solutions.
A typical solution is described below.
In the scheme, the network side control equipment measures and counts the motion state of the mobile station when the mobile station passes through the micro area. Specifically, if the network side control device determines that the mobile station moves in Q microcells among P microcells through which the mobile station passes, the mobile station is determined to be in a fast moving state, and the mobile station is handed over to the macrocell, and the macrocell continues to provide service to the user, thereby reducing the frequency of handover between cells. As a practical example, if a mobile station stays in a cell for only 5 minutes, the cell determines that the mobile station is in a fast moving state. If Q cells in P cells passed by the mobile station consider that the mobile station is in a fast moving state, the network side control equipment switches the mobile station to the macro cell so as to reduce the frequency of switching.
In practical applications, the above solution still cannot completely and effectively avoid the problem of voice interruption or disconnection that may be encountered when the mobile station user is in fast motion while talking.
One of the main reasons for this is that the above-described scheme requires a long time for determining whether the mobile station is moving fast, i.e. when the decision is made, the mobile station has already undergone a number of handovers. Therefore, this method is not sensitive to fast movements; in addition, since fast moving mobile stations are usually fast moving along roads or railways in practice, the movement route has a linear characteristic, but the above scheme does not take the particularity of the movement into consideration and optimizes the switching method accordingly.
Disclosure of Invention
The technical problem to be solved by the present invention is to provide a method for handover of a mobile station in a mobile communication system, so that a user of the mobile station can still enjoy good communication quality under the condition of fast movement.
In order to solve the above technical problem, the present invention provides a method for performing a handover of a mobile station in a mobile communication system, comprising:
a, a mobile communication system calculates the moving speed of a mobile station moving along a linear road, wherein a linear relevant cell is preset in the linear road area;
b, the network side control device judges whether the mobile station is in a fast motion state according to the moving speed of the mobile station, if so, the step C is carried out, and if not, the step D is carried out;
c, the network side control equipment improves the linear correlation priority of the linear correlation cell of the linear road and enters the step E;
d, the network side control equipment cancels the linear correlation priority of the linear correlation cell of the linear road and enters the step E;
e, the network side control device takes the linear correlation priority of the linear correlation cell as one of parameters to calculate the total switching priority value corresponding to each candidate linear correlation cell which can be switched by the mobile station;
and F, the network side control equipment selects the cell with the maximum total switching priority to implement switching.
In addition, the step A further comprises the following steps:
a1 measuring the frequency of the wireless signal transmitted by the mobile station by the cell base station;
a2, the cell base station calculates the frequency deviation between the measured wireless signal frequency and the standard frequency, and reports the frequency deviation to the network side control equipment;
a3, the network side control device calculates the moving speed of the mobile station according to the frequency deviation of the wireless signal and the known wavelength corresponding to the mobile station communication frequency point,
wherein,
the moving speed of the mobile station is the frequency shift, which is the wavelength corresponding to the call frequency point of the mobile station.
In addition, the step B also comprises the following steps:
b1 the network side control device counts how many of the N moving speeds of the mobile station obtained in the last N times are larger than the speed threshold value;
b2 the network side control device judges whether the number larger than the speed threshold exceeds the overspeed number threshold, if yes, it judges the mobile station is in the fast moving state, if not, it judges the mobile station is not in the fast moving state.
In addition, the speed threshold in step B1 and the overspeed number threshold in step B2 are both preset in the network-side control device.
In addition, the linear road may be a road or a railway
The difference between the technical scheme of the invention and the prior art can be found by comparison, firstly, the invention calculates the moving speed of the mobile station according to the Doppler shift effect by measuring the frequency of the wireless signal sent by the mobile station; secondly, the invention sets the district for the road with linear characteristic, introduces and utilizes the concept of 'linear relative district'.
The difference in the technical scheme brings obvious beneficial effects: firstly, because the Doppler frequency shift effect has the characteristic of instantaneity, the calculation of the speed of the mobile station can be completed within the time of second level, the defect that whether the mobile station moves fast or not in the prior art is overcome, the sensitivity of a network to the fast movement of the mobile station is improved, and in addition, the calculation of the moving speed of the mobile station through the Doppler frequency shift effect is accurate; secondly, by setting the 'linear correlation cell', when the mobile station moves fast, the method of preferentially cutting the linear correlation cell can reduce the times of error switching and improve the conversation performance, and when the mobile station moves at low speed, the linear correlation priority of the linear correlation cell is cancelled, and then the mobile station can select and switch into a proper cell in a common way after the moving trend of the mobile station is clear.
Drawings
FIG. 1 is a schematic diagram of a linear road and its linear associated cells according to the present invention;
fig. 2 is a flowchart of a handoff method of a mobile station according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings.
Referring to fig. 1, a linear road 10 may be a highway or a railway, and 3 cells are distributed along the road from south to north in sequence: cell 20, cell 30, and cell 40. In the present embodiment, since the coverage area of the cell 40 and the cell 20 on the road is relatively large, they are set as the line-shaped relevant cells. Since the coverage area of the cell 30 on the road 10 is relatively small and the coverage of the road 10 can be completely replaced by the cell 40 and the cell 20, the cell 30 is not set as a line-shaped related cell in the present embodiment.
The overall process of the mobile station handoff in one embodiment of the present invention is described below with reference to fig. 2.
In this embodiment, a mobile station is talking in the area of cell 40, is moving rapidly from south to north along road 10, and is approaching the overlapping coverage areas of cell 20, cell 30, and cell 40.
At this time, referring to step 100 in fig. 2, the mobile communication system first calculates the moving speed of the mobile station. In this embodiment, the specific way of calculating the moving speed of the mobile station is as follows:
first, when a mobile station gradually approaches the cell 20, a base station of the cell 40 receives a radio signal transmitted thereto by the mobile station and measures the frequency of the radio signal;
then, the base station of the cell 40 subtracts the measured frequency of the wireless signal from the standard frequency to obtain the frequency offset of the wireless signal, and reports the frequency offset to the network side control device;
it should be noted that the network side control device is a generic term for a corresponding device in different types of mobile Communication systems, and the present invention particularly refers to a device for controlling a handover portion, for example, in a Global System for mobile Communication (GSM), it is usually referred to as a Base Station Controller (BSC), but not limited to the BSC; in a Code Division Multiple Access (CDMA) communication system, it is also commonly referred to as a BSC, but is not limited to a BSC; in a Wideband Code Division Multiple Access (WCDMA) communication system, it is usually referred to as a Radio Network Controller (RNC), but not limited to the RNC.
Then, the network side control device calculates the moving speed of the mobile station according to the doppler effect by using the frequency offset reported by the base station of the cell 40 and the known wavelength corresponding to the mobile station communication frequency point:
moving speed of mobile station as frequency deviation and wavelength corresponding to conversation frequency point of mobile station
According to the formula, because the wavelength corresponding to the conversation frequency point of the mobile station is known in advance, the network side control equipment can calculate the real-time moving speed of the mobile station by using the frequency offset data acquired in real time.
In addition, since the frequency offset data has both positive and negative cases, the moving speed of the mobile station calculated by the above formula also has both positive and negative cases. In this embodiment, if the frequency offset data is positive, it represents that the mobile station is approaching the base station of the cell 40, and if the frequency offset data is negative, it represents that the mobile station is leaving the base station of the cell 40.
It should be noted that, in the present invention, the calculation of the moving speed of the mobile station is performed only when the mobile station is in a call, and is performed all the time during the call. The mobile station does not calculate its moving speed when it is not communicating.
After calculating the moving speed of the mobile station in step 100, the process proceeds to step 200, where the network-side control device determines whether the mobile station is in a fast moving state or not according to the known moving speed. In the present invention, the determination may be implemented in various ways, and the determination method adopted in the embodiment is described in detail below:
two thresholds are preset in the network side control device: one is a speed threshold and the other is a number of overspeed threshold (i.e., a threshold of the number of times the speed threshold is exceeded). Counting how many of the moving speeds of the N mobile stations obtained in the last N times of calculation are larger than a speed threshold value, and then judging whether the number larger than the speed threshold value exceeds a preset overspeed number threshold value.
If the mobile station is in the fast moving state, the mobile station is judged to be in the fast moving state, and if the mobile station is not in the fast moving state, the mobile station is judged to be in the fast moving state.
The method for obtaining the motion state conclusion of the mobile station through statistics for a plurality of times can effectively overcome misjudgment caused by abnormal speed due to accidental factors. In addition, in actual operation, the network side control device may determine whether the mobile station is in the fast moving state within a time period of the order of seconds, which is more sensitive to the change of the moving state of the mobile station compared to the above-described prior art.
If the network-side control apparatus determines in step 200 that the mobile station is in a fast-moving state, it proceeds to step 300. In this step, the network-side control device raises the linear correlation priority of the linear correlation cell 20.
It should be noted that, in the current mobile communication technology, a plurality of priority parameters for determining cell handover, such as the strength of signals of each cell, frequency bands, the size of coverage area of the cell, etc., have been defined in advance in the network side control device. The invention adds a priority parameter for cell switching, namely a linear correlation priority parameter. And setting corresponding values for the line-form related priority parameters according to whether the mobile station is in a fast motion state or not.
On the other hand, if the network-side control apparatus determines in step 200 that the mobile station is not in the fast moving state, it proceeds to step 400. In this step, the network-side control device cancels the above-described linear correlation priority of the linear correlation cell 20.
There are two cases. In the first case, the mobile station is in a high-speed moving state, which increases the linear correlation priority of the linear correlation cell 20, but the mobile station performs a deceleration movement thereafter, so that the network-side control device determines that the mobile station is not in a fast movement, and at this time, as described above, the network-side control device cancels the linear correlation priority of the linear correlation cell 20; in the second case, the mobile station was not in fast motion, and there is no need to cancel the line-shaped correlation priority in step 400.
After steps 300 and 400 are completed, step 500 is entered. In this step, the network side control device may calculate a total handover priority value corresponding to each candidate cell to which the mobile station can be handed over, according to each priority parameter for handover of each cell. And sorting the candidate cells according to the size of the total switching priority value.
Thereafter, in step 600, the network side control device selects the cell with the largest total handover priority value in the ranking results to perform handover. In this embodiment, since the cell 20 increases the linear correlation priority in step 300, so that the total handover priority value is correspondingly increased and is greater than the total handover priority value of another candidate cell, i.e. the cell 30, the network side control device selects the cell 20 to perform handover.
Of course, it can be known from the above description of the procedure that if the mobile station does not enter the fast moving state all the time, the setting of the linearly related cell has no influence on the cell handover of the mobile station.
It should be noted that The present invention is applicable to various mobile communication systems, including but not limited to GSM communication system, CDMA communication system, WCDMA communication system, third generation mobile communication (The third generation, abbreviated as "3G"), trunking communication system, etc.
While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (6)
1. A method for handoff of a mobile station in a mobile communication system, comprising the steps of:
a, a mobile communication system calculates the moving speed of a mobile station moving along a linear road, wherein a linear relevant cell is preset in the linear road area;
b, the network side control device judges whether the mobile station is in a fast motion state according to the moving speed of the mobile station, if so, the step C is carried out, and if not, the step D is carried out;
c, the network side control equipment improves the linear correlation priority of the linear correlation cell of the linear road and enters the step E;
d, the network side control equipment cancels the linear correlation priority of the linear correlation cell of the linear road and enters the step E;
e, the network side control device takes the linear correlation priority of the linear correlation cell as one of parameters to calculate the total switching priority value corresponding to each candidate linear correlation cell which can be switched by the mobile station;
and F, the network side control equipment selects the cell with the maximum total switching priority to implement switching.
2. The method of mobile station handoff in a mobile communication system according to claim 1, wherein said step a further comprises the steps of:
a1 measuring the frequency of the wireless signal transmitted by the mobile station by the cell base station;
a2, the cell base station calculates the frequency deviation between the measured wireless signal frequency and the standard frequency, and reports the frequency deviation to the network side control equipment;
a3, the network side control device calculates the moving speed of the mobile station according to the frequency deviation of the wireless signal and the known wavelength corresponding to the mobile station communication frequency point,
wherein,
the moving speed of the mobile station is the frequency shift, which is the wavelength corresponding to the call frequency point of the mobile station.
3. The method of mobile station handoff in a mobile communication system according to claim 1, wherein said step B further comprises the steps of:
b1 the network side control device counts how many of the N moving speeds of the mobile station obtained in the last N times are larger than the speed threshold value;
b2 the network side control device judges whether the number larger than the speed threshold exceeds the overspeed number threshold, if yes, it judges the mobile station is in the fast moving state, if not, it judges the mobile station is not in the fast moving state.
4. The method as claimed in claim 3, wherein the speed threshold in step B1 and the overspeed number threshold in step B2 are preset in said network side control device.
5. The method of mobile station handoff in a mobile communication system of claim 1, wherein said linear road is a road.
6. The method for mobile station handoff in a mobile communication system according to claim 1, wherein said linear road is a railway.
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| CNB031488935A CN100396144C (en) | 2003-06-16 | 2003-06-16 | Method of cross-region switching in mobile communication system |
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| CNB031488935A CN100396144C (en) | 2003-06-16 | 2003-06-16 | Method of cross-region switching in mobile communication system |
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| CN100396144C true CN100396144C (en) | 2008-06-18 |
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Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101227705B (en) * | 2007-01-17 | 2012-09-05 | 华为技术有限公司 | System and method for switching terminal to macro cell and terminal, access node and gateway thereof |
| CN101184331B (en) * | 2007-11-07 | 2010-08-18 | 孟庆刚 | Statistical path based switch method in wireless communication system |
| CN101754293B (en) * | 2008-12-22 | 2015-03-11 | 上海华为技术有限公司 | Switching method and relevant device thereof |
| CN101986748B (en) * | 2009-07-29 | 2015-05-20 | 中兴通讯股份有限公司 | Method and system for reporting measurement result as well as method and system for switching cells |
| CN102595522A (en) * | 2012-01-20 | 2012-07-18 | 中兴通讯股份有限公司 | Mobility enhancement method, user equipment and base station |
| US9173151B2 (en) * | 2012-08-07 | 2015-10-27 | Marvell World Trade Ltd. | User mobility control for heterogeneous wireless networks |
| WO2015103740A1 (en) * | 2014-01-08 | 2015-07-16 | 华为终端有限公司 | Cell switching method and terminal |
| CN116761151B (en) * | 2023-08-18 | 2023-11-28 | 深圳前海中电慧安科技有限公司 | Rail transit network switching method, device, equipment and medium |
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| CN1146271A (en) * | 1994-04-15 | 1997-03-26 | 诺基亚电信公司 | Handover with fast moving mobile station between microcell and macrocell |
| CN1308478A (en) * | 1999-12-30 | 2001-08-15 | 三星电子株式会社 | Cross-region switching device and method in mobile comm system |
| CN1336090A (en) * | 1998-12-22 | 2002-02-13 | 艾利森电话股份有限公司 | Improved CDMA soft hand-off |
| WO2002093813A1 (en) * | 2001-05-15 | 2002-11-21 | Nokia Corporation | A method of channel allocation for a mobile terminal moving in a cellular communication network |
| CN1395429A (en) * | 2001-07-09 | 2003-02-05 | 电子科技大学 | Method for measuring motion speed of mobile station in mobile communication |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1146271A (en) * | 1994-04-15 | 1997-03-26 | 诺基亚电信公司 | Handover with fast moving mobile station between microcell and macrocell |
| CN1336090A (en) * | 1998-12-22 | 2002-02-13 | 艾利森电话股份有限公司 | Improved CDMA soft hand-off |
| CN1308478A (en) * | 1999-12-30 | 2001-08-15 | 三星电子株式会社 | Cross-region switching device and method in mobile comm system |
| WO2002093813A1 (en) * | 2001-05-15 | 2002-11-21 | Nokia Corporation | A method of channel allocation for a mobile terminal moving in a cellular communication network |
| CN1395429A (en) * | 2001-07-09 | 2003-02-05 | 电子科技大学 | Method for measuring motion speed of mobile station in mobile communication |
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