CN109219091B - VoLTE cell switching method, device and base station - Google Patents
VoLTE cell switching method, device and base station Download PDFInfo
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- CN109219091B CN109219091B CN201710510873.0A CN201710510873A CN109219091B CN 109219091 B CN109219091 B CN 109219091B CN 201710510873 A CN201710510873 A CN 201710510873A CN 109219091 B CN109219091 B CN 109219091B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/0005—Control or signalling for completing the hand-off
- H04W36/0083—Determination of parameters used for hand-off, e.g. generation or modification of neighbour cell lists
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/08—Reselecting an access point
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/24—Reselection being triggered by specific parameters
- H04W36/32—Reselection being triggered by specific parameters by location or mobility data, e.g. speed data
Abstract
The invention discloses a VoLTE cell switching method, a VoLTE cell switching device and a base station, and relates to the field of LTE. The method comprises the following steps: acquiring the moving speed of a terminal in a vehicle; dynamically adjusting the switching parameters in the switching judgment formula of the A3 event according to the moving speed of the terminal; and determining the switching time of the VoLTE cell based on the adjusted switching judgment formula. The invention dynamically changes the switching between the VoLTE/LTE base stations according to the fast or slow moving speed of the terminal in the vehicle, and solves the problems of switching failure and VoLTE call drop caused by the change of the terminal speed by adopting fixed value switching parameters at present.
Description
Technical Field
The present invention relates to the field of LTE (Long Term Evolution, 3 GPP), and in particular, to a method, an apparatus, and a base station for switching a VoLTE (Voice over LTE, LTE) cell.
Background
In a VoLTE/LTE communication system in a high-speed rail environment, cell switching is frequent, switching time is short, requirements on switching power are high, otherwise, the VoLTE is easy to fail to switch, the call drop rate of the VoLTE is increased, and the user experience of the VoLTE is influenced.
At present, the inter-cell switching (same frequency switching) of the VoLTE/LTE communication system under the high-speed rail environment, the A3 event triggering of the same frequency switching, and a unified set of switching parameters, namely the parameters in the A3 event triggering condition formula are fixed and unchanged. Referring to the specification of 3GPP 36.331, the handover decision formula based on the A3 event (i.e., the A3 event trigger condition formula) is:
Mn+ocn-hys＞Ms+ocs+off (1)
where Mn is the measurement result of the neighboring cell, ocn is the cell specific offset of the neighboring cell, if the neighboring cell is not configured, the value is 0, Ms is the measurement result of the serving cell, ocs is the cell specific offset of the serving cell, if the serving cell is not configured, the value is 0, hys is the hysteresis of the event, and off is the offset of the event.
If there is no offset between the neighboring and serving cells, i.e. ocn is 0 and ocs is 0, or the neighboring and serving cells ocn and ocs are set to be the same, the formula is simplified as:
Mn-hys＞Ms+off (2)
once optimized, the VoLTE/LTE network is fixed at hys and off during network operation. In a high-speed rail environment, when hys and off are fixed once, the running speed of a train changes such as going out, arriving, getting out of track, changing speed midway or stopping due to reasons, as shown in fig. 1 and fig. 2, a too early switching phenomenon or a too late switching phenomenon occurs, which easily causes a VoLTE call drop caused by a switching failure, and seriously affects the use experience of a VoLTE user.
However, the conventional optimization method for the VoLTE switching parameters in the high-speed rail environment needs repeated testing and optimization according to different road sections, so that the workload is huge, and after the optimization is completed, the switching parameters are fixed and cannot adapt to the speed change of the high-speed rail.
Disclosure of Invention
The invention aims to provide a VoLTE cell switching method, a device and a base station, which can solve the problems of switching failure and VoLTE call drop caused by the change of terminal speed due to the adoption of fixed value switching parameters at present.
According to an aspect of the present invention, a VoLTE cell handover method is provided, including: acquiring the moving speed of a terminal in a vehicle; dynamically adjusting the switching parameters in the switching judgment formula of the A3 event according to the moving speed of the terminal; and determining the switching time of the VoLTE cell based on the adjusted switching judgment formula.
Further, the handover parameters include a hysteresis parameter and an offset parameter; determining hysteresis parameter hys according to formula hys 0-K1. V; determining an offset value parameter off according to a formula off0-K2 & V; when meeting a switching judgment formula Mn-hys & gtMs + off, carrying out VoLTE cell switching; wherein hys0 and off0 are initial values, K1 and K2 are correction coefficients, V is the moving speed of the terminal, Mn is the measurement result of the neighboring cell, and Ms is the measurement result of the serving cell.
Further, the correction parameters K1, K2 are related to the radius of the base station and the moving speed of the terminal.
Further, acquiring the moving speed of the terminal in the vehicle includes: obtaining Doppler frequency offset of a terminal in a vehicle; the moving speed of the terminal is determined based on the doppler frequency offset.
Further according to the formula
Determining the moving speed V of the terminal; wherein f isdIs the Doppler frequency offset, c is the electromagnetic wave propagation speed, f is the carrier frequency, and alpha is the angle between the terminal moving direction and the signal propagation direction.
According to another aspect of the present invention, a VoLTE cell switching apparatus is further provided, including: a terminal moving speed acquisition unit for acquiring a moving speed of a terminal in a vehicle; the switching parameter dynamic adjusting unit is used for dynamically adjusting the switching parameters in the switching judgment formula of the A3 event according to the moving speed of the terminal; and the VoLTE cell switching unit is used for determining the switching time of the VoLTE cell based on the adjusted switching judgment formula.
Further, the handover parameters include a hysteresis parameter and an offset parameter; the switching parameter dynamic adjusting unit is used for determining a hysteresis parameter hys according to a formula hys0-K1 & V and determining an offset parameter off according to a formula off0-K2 & V; the VoLTE cell switching unit is used for switching the VoLTE cell when the formula Mn-hys is larger than Ms + off; wherein hys0 and off0 are initial values, K1 and K2 are correction coefficients, V is the moving speed of the terminal, Mn is the measurement result of the neighboring cell, and Ms is the measurement result of the serving cell.
Further, the correction parameters K1, K2 are related to the radius of the base station and the moving speed of the terminal.
Further, the terminal moving speed obtaining unit is used for obtaining the Doppler frequency offset of the terminal in the vehicle, and determining the moving speed of the terminal based on the Doppler frequency offset.
Further, the terminal moving speed obtaining unit is used for obtaining the terminal moving speed according to a formula
Determining the moving speed V of the terminal; wherein f isdIs the Doppler frequency offset, c is the electromagnetic wave propagation speed, f is the carrier frequency, and alpha is the angle between the terminal moving direction and the signal propagation direction.
According to another aspect of the present invention, a base station is also provided, which includes the VoLTE cell switching apparatus described above.
According to another aspect of the present invention, a VoLTE cell switching apparatus is further provided, including: a memory; and a processor coupled to the memory, the processor configured to perform the method as described above based on instructions stored in the memory.
According to another aspect of the present invention, a computer-readable storage medium is also proposed, on which computer program instructions are stored, which instructions, when executed by a processor, implement the steps of the above-described method.
Compared with the prior art, the method and the device dynamically adjust the hysteresis parameter hys and the offset parameter off in the switching decision formula of the A3 event according to the moving speed of the terminal, and determine the switching time of the VoLTE cell based on the adjusted switching decision formula, so that the switching between the VoLTE/LTE base stations can be dynamically changed early or late by using the fast or slow moving speed of the terminal in the vehicle, and the problems of switching failure and VoLTE call drop caused by the change of the terminal speed by adopting the fixed value switching parameter at present are solved.
Other features of the present invention and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.
The invention will be more clearly understood from the following detailed description, taken with reference to the accompanying drawings, in which:
fig. 1 shows a phenomenon of early switching when a train decelerates in the prior art.
Fig. 2 shows a hysteresis switching phenomenon in a prior art train acceleration.
Fig. 3 is a flowchart illustrating a VoLTE cell handover method according to an embodiment of the present invention.
Fig. 4 is a flowchart illustrating a VoLTE cell handover method according to another embodiment of the present invention.
Fig. 5 is a schematic diagram of an included angle between a moving direction of a terminal and a signal propagation direction according to the present invention.
Fig. 6 is a schematic diagram of VoLTE cell handover when the high speed rail is changed.
Fig. 7 is a schematic structural diagram of a VoLTE cell switching apparatus according to an embodiment of the present invention.
Fig. 8 is a schematic structural diagram of a VoLTE cell switching apparatus according to another embodiment of the present invention.
Fig. 9 is a schematic structural diagram of a VoLTE cell switching apparatus according to still another embodiment of the present invention.
Detailed Description
Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.
Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description.
The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.
Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.
In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to specific embodiments and the accompanying drawings.
Fig. 3 is a flowchart illustrating a VoLTE cell handover method according to an embodiment of the present invention. The method comprises the following steps:
in step 310, the moving speed of the terminal in the vehicle is acquired. For example, in a high-speed rail environment, the base station may perform a moving speed measurement on a terminal on a high-speed rail, i.e., a speed at which the high-speed rail runs. The base station may perform DFO (Doppler frequency offset) measurement on the terminal, calculate the moving speed of the terminal on the high-speed rail, and acquire the moving speed of the terminal in other manners. For example, the terminal turns on a GPS module switch, and continuously reports the latitude and longitude information of the terminal, and the base station calculates the moving speed of the terminal according to the latitude and longitude information.
In step 320, the handover parameters in the handover decision formula of the a3 event are dynamically adjusted according to the moving speed of the terminal. For example, after obtaining the terminal moving speed V, the formula (2) is modified to obtain the formula (3).
Mn-hys*＞Ms+off* (3)
The hysteresis parameter hys is hys0-K1 · V, the offset parameter off is off0-K2 · V, hys0, and off0 are initial values, K1 and K2 are correction parameters, Mn is a measurement result of the neighboring cell, and Ms is a measurement result of the serving cell.
In step 330, the time of the VoLTE cell handover is determined based on the adjusted handover decision formula. According to the above switching decision formula (3), it can be seen that when the terminal moving speed becomes higher, hys × off value becomes lower, and switching is performed in advance; when the terminal moving speed becomes lower, hys ×, off ×, the value becomes larger, and the switching is performed after a delay.
In the embodiment, the hysteresis parameter hys and the offset parameter off in the handover decision formula of the a3 event are dynamically adjusted according to the moving speed of the terminal, and the time of the VoLTE cell handover is determined based on the adjusted handover decision formula, so that the early or late time of the handover between VoLTE/LTE base stations is dynamically changed by using the fast or slow moving speed of the terminal in the vehicle, and the problems of handover failure and VoLTE call drop caused by the change of the terminal speed due to the adoption of the fixed value handover parameter at present are solved.
Fig. 4 is a flowchart illustrating a VoLTE cell handover method according to another embodiment of the present invention.
In step 410, the base station acquires the doppler frequency offset of the terminal in the vehicle. Wherein, a Doppler Frequency Offset (DFO) measuring module may be added in the base station to obtain the doppler frequency offset f of the terminald。
In step 420, the moving speed of the terminal is determined based on the doppler frequency offset. Wherein the moving speed V of the terminal can be determined according to equation (4).
Wherein c is the propagation speed of electromagnetic wave, wherein c is 3 × 10^5km/s, f is the carrier frequency, and α is the angle between the terminal moving direction and the signal propagation direction.
As shown in fig. 5, when the mobile terminal moves within the handover band after the positions of two adjacent base stations and the handover band are fixed, the included angle α is also approximately fixed. For example, base stations are generally built along the edge of a railway, the tower heights of the base stations are known, and assuming that the height h of the base station is 200 meters and the radius Rs of a handover band is 2.1 kilometers, α ═ arctan (h/Rs) ═ arctan (0.0952).
In step 430, hysteresis parameter hys and offset parameter off of the handover decision formula are determined based on the moving speed of the terminal, wherein hys ═ f1(V) ═ hys0-K1 · V, and off ═ f2(V) ═ off0-K2 · V. The correction parameters K1 and K2 are related to the radius of the base station and the moving speed of the terminal, and can be corrected appropriately according to different road sections, station addresses and other conditions.
In step 440, VoLTE cell handover is performed when the handover decision formula Mn-hys > Ms + off is satisfied. When the train decelerates, hys values and off values become larger, switching is carried out after lagging, the previous switching is counteracted, and the switching is normal; when the train accelerates, hys and off values become small, and the switching is performed in advance, so that the switching is normal by offsetting the lagging switching which occurs before.
In the embodiment, the switching parameters are dynamically adjusted according to the vehicle running speed, the switching time delay is reduced, and the VoLTE switching is more accurate in time and position, so that the purpose that the switching between the VoLTE base stations is changed early or late dynamically by using the high-speed or low-speed terminal on the high-speed rail is achieved, the VoLTE switching is more accurate in the high-speed rail environment, the VoLTE switching success rate is improved, the VoLTE drop rate is reduced, the VoLTE service continuity on the high-speed rail is ensured, the VoLTE service quality and the user experience are improved, and the VoLTE service expansion on the high-speed rail is promoted.
Fig. 6 is a schematic diagram of VoLTE cell handover when the high speed rail is changed.
For example, a Doppler Frequency Offset (DFO) measurement module is added to the base station eNB to measure the moving speed of the terminal UE. Then, according to the formula hys ═ f1(V) ═ hys0-K1 · V, and off ═ f2(V) ═ off0-K2 · V, a hysteresis parameter hys ═ and an offset value parameter off are calculated. According to the formula (3), Mn-hys0+ (K1+ K2). V > Ms + off0, and if V ═ V0+ Δ V, Mn-hys0+ (K1+ K2) · (V0+ Δ V) > Ms + off0 is obtained.
Hys0 and off0 are fixed initial values, hys0 and off0 can be set for a moving speed of 200 km/h, K1 and K2 are correction parameters, where K1 is assumed to be 0.55, K2 is assumed to be 0.55, and K1+ K2 is 1.1, where the correction parameters can give a correction through experiments according to an actual route, V0 is an average speed, here is assumed to be 200 km/h, Δ V is positive when a high-speed iron speed becomes fast, Δ V is negative when the high-speed iron speed becomes slow, and a range of Δ V can be corrected according to an actual situation, for example, is-200 km/h to 200 km/h, that is, a terminal moving speed can be sensed from 0 km/h to 400 km/h.
If the terminal moving speed is 200 km/h, the radius of the base station cell is 2 km, the train head moves from the position of the vertical base station eNB _ a to the edge of the base station eNB _ a, and the distance is approximately 36 seconds, i.e. R/V0 is 2/200 3600, and the handover is not advanced or delayed.
When the high-speed rail enters the switching zone, the high-speed rail speed is increased, for example, the UE moving speed is 250 km/h, R/(V0+ Δ V) 2/250 × 3600 is 28.8 seconds, 36-28.8 is 7.2 seconds, and then multiplied by the correction parameter 1.1 to obtain 7.2 × 1.1 is 7.92 seconds, so that it is necessary to advance 7.92 seconds for switching to ensure normal switching. That is, as the UE moving speed increases, the hys × and off values decrease, and the UE performs handover earlier to offset the late handover occurring before, so as to ensure normal handover of the UE with increased speed.
When the high-speed rail enters the switching zone, the high-speed rail is slowed, for example, the UE moving speed is 150 km/h, R/(V0+ Δ V) 2/150 × 3600 is 48 seconds, 48-36 is 12 seconds, and then the result is multiplied by a correction parameter 1.1 to obtain 12 × 1.1 is 13.2 seconds, so that it takes 13.2 seconds to delay the switching to ensure the normal switching. That is, as the UE moving speed decreases, the hys × and off values increase, and the UE switches after delaying, so as to cancel the earlier switching that occurred before, and ensure normal UE switching in deceleration.
In this embodiment, when the train accelerates, hys and off values become small, switching is performed in advance, the previous lagging switching is counteracted, and the switching is normal; when the train decelerates, hys and off values become large, switching is performed after a delay, and the switching is normal by offsetting the previous switching. The problem of VoLTE call drop caused by untimely (too early or too late) VoLTE switching under a high-speed rail environment is effectively solved, and the user experience of VoLTE is improved; in addition, the mobile speed of the terminal is increased to judge the switching time, so that the method is suitable for low-speed, medium-speed and high-speed operation of the terminal, has strong applicability, is convenient for popularization and deployment, and saves network optimization time and cost; meanwhile, LTE network switching signaling is reduced, and the utilization rate of LTE network resources is improved; moreover, terminal software does not need to be modified, namely, the terminal is not affected, only base station side software upgrading is needed, the implementation is simple, and good backward compatibility and deployment feasibility are achieved.
Fig. 7 is a schematic structural diagram of a VoLTE cell switching apparatus according to an embodiment of the present invention. The device comprises a terminal moving speed acquisition unit 710, a switching parameter dynamic adjustment unit 720 and a VoLTE cell switching unit 730, wherein:
the terminal moving speed acquisition unit 710 is configured to acquire a moving speed of the terminal in the vehicle. The terminal can be measured by the base station through DFO, the moving speed of the terminal on the vehicle can be calculated, and the moving speed of the terminal can be obtained through other modes. For example, the terminal turns on a GPS module switch, and continuously reports the latitude and longitude information of the terminal, and the base station calculates the moving speed of the terminal according to the latitude and longitude information.
In one embodiment, the terminal moving speed obtaining unit 710 obtains a doppler frequency offset amount of the terminal in the vehicle, determines a moving speed of the terminal based on the doppler frequency offset amount, for example, according to a formula
The moving speed V of the terminal is determined. f. ofdIs the Doppler frequency offset, c is the electromagnetic wave propagation speed, f is the carrier frequency, and alpha is the angle between the terminal moving direction and the signal propagation direction.
The handover parameter dynamic adjustment unit 720 is configured to dynamically adjust a handover parameter in a handover decision formula of the a3 event according to the moving speed of the terminal. For example, after obtaining the terminal moving speed V, the hysteresis parameter hys is determined to be hys0-K1 · V, the offset parameter off is determined to be off0-K2 · V, hys0, and off0 as initial values, K1 and K2 are correction parameters, Mn is a measurement result of the neighboring cell, and Ms is a measurement result of the serving cell. The correction parameters K1 and K2 are related to the radius of the base station and the moving speed of the terminal, and can be corrected appropriately according to different road sections, station addresses and other conditions.
The VoLTE cell switching unit 730 is configured to determine a time of VoLTE cell switching based on the adjusted switching decision formula. That is, VoLTE cell switching is performed when Mn-hys > Ms + off is satisfied. When the train decelerates, hys values and off values become larger, switching is carried out after lagging, the previous switching is counteracted, and the switching is normal; when the train accelerates, hys and off values become small, and the switching is performed in advance, so that the switching is normal by offsetting the lagging switching which occurs before.
In the embodiment, the hysteresis parameter hys and the offset parameter off in the handover decision formula of the a3 event are dynamically adjusted according to the moving speed of the terminal, and the time of the VoLTE cell handover is determined based on the adjusted handover decision formula, so that the early or late time of the handover between VoLTE/LTE base stations is dynamically changed by using the fast or slow moving speed of the terminal in the vehicle, and the problems of handover failure and VoLTE call drop caused by the change of the terminal speed due to the adoption of the fixed value handover parameter at present are solved.
In another embodiment of the present invention, a base station includes the VoLTE cell switching device in the above embodiment, and by setting the VoLTE cell switching device in the base station, the switching parameters can be dynamically adjusted according to the vehicle running speed, so as to reduce the switching delay, so that VoLTE switching is more accurate in time and position, thereby effectively solving the problem of VoLTE call drop caused by untimely (too early or too late) VoLTE switching in a high-speed rail environment, and improving the user experience of VoLTE; in addition, the mobile speed of the terminal is increased to judge the switching time, so that the method is suitable for low-speed, medium-speed and high-speed operation of the terminal, has strong applicability, is convenient for popularization and deployment, and saves network optimization time and cost; meanwhile, LTE network switching signaling is reduced, and the utilization rate of LTE network resources is improved; moreover, terminal software does not need to be modified, namely, the terminal is not affected, only base station side software upgrading is needed, the implementation is simple, and good backward compatibility and deployment feasibility are achieved.
Fig. 8 is a schematic structural diagram of a VoLTE cell switching apparatus according to another embodiment of the present invention. The apparatus includes a memory 810 and a processor 820. Wherein:
the memory 810 may be a magnetic disk, flash memory, or any other non-volatile storage medium. The memory is used to store instructions in the embodiments corresponding to fig. 3-4.
In one embodiment, as also shown in FIG. 9, the system 900 includes a memory 910 and a processor 920. Processor 920 is coupled to memory 910 by a BUS 930. The system 900 may also be coupled to an external storage device 950 via a storage interface 940 for facilitating retrieval of external data, and may also be coupled to a network or another computer system (not shown) via a network interface 960, which will not be described in detail herein.
In the embodiment, the data instruction is stored in the memory, and the instruction is processed by the processor, so that the VoLTE switching is more accurate in a high-speed rail environment, the VoLTE switching success rate is improved, the VoLTE call drop rate is reduced, the VoLTE service continuity on the high-speed rail is ensured, the VoLTE service quality and the user experience are improved, and the VoLTE service expansion on the high-speed rail is promoted.
In another embodiment, a computer-readable storage medium has stored thereon computer program instructions which, when executed by a processor, implement the steps of the method in the corresponding embodiments of fig. 1, 2. As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, apparatus, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable non-transitory storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
Thus far, the present invention has been described in detail. Some details well known in the art have not been described in order to avoid obscuring the concepts of the present invention. It will be fully apparent to those skilled in the art from the foregoing description how to practice the presently disclosed embodiments.
The method and apparatus of the present invention may be implemented in a number of ways. For example, the methods and apparatus of the present invention may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order for the steps of the method is for illustrative purposes only, and the steps of the method of the present invention are not limited to the order specifically described above unless specifically indicated otherwise. Furthermore, in some embodiments, the present invention may also be embodied as a program recorded in a recording medium, the program including machine-readable instructions for implementing a method according to the present invention. Thus, the present invention also covers a recording medium storing a program for executing the method according to the present invention.
Although some specific embodiments of the present invention have been described in detail by way of illustration, it should be understood by those skilled in the art that the above illustration is only for the purpose of illustration and is not intended to limit the scope of the invention. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.
Claims (9)
1. A VoLTE cell switching method is characterized by comprising the following steps:
acquiring the moving speed of a terminal in a vehicle;
dynamically adjusting a hysteresis parameter and an offset value parameter in a switching decision formula of the A3 event according to the moving speed of the terminal, wherein the hysteresis parameter hys is determined according to a formula hys0-K1 & V, and the offset value parameter off is determined according to a formula off0-K2 & V;
when meeting a switching judgment formula Mn-hys Ms + off, carrying out VoLTE cell switching;
wherein hys0 and off0 are initial values, K1 and K2 are correction coefficients, the correction coefficients K1 and K2 are related to the radius of the base station and the moving speed of the terminal, V is the moving speed of the terminal, Mn is the measurement result of the neighboring cell, and Ms is the measurement result of the serving cell.
2. The method of claim 1, wherein obtaining the moving speed of the terminal in the vehicle comprises:
acquiring Doppler frequency offset of the terminal in the vehicle;
and determining the moving speed of the terminal based on the Doppler frequency offset.
3. The method of claim 2,
according to the formula
Determining the moving speed V of the terminal;
wherein f isdAnd c is the Doppler frequency offset, c is the electromagnetic wave propagation speed, f is the carrier frequency, and alpha is the included angle between the terminal moving direction and the signal propagation direction.
4. A VoLTE cell switching apparatus, comprising:
a terminal moving speed acquisition unit for acquiring a moving speed of a terminal in a vehicle;
a switching parameter dynamic adjusting unit, configured to dynamically adjust a hysteresis parameter and an offset value parameter in a switching decision formula of the a3 event according to the moving speed of the terminal, where the hysteresis parameter hys is determined according to a formula hys0-K1 · V, and the offset value parameter off is determined according to a formula off0-K2 · V;
a VoLTE cell switching unit, configured to perform VoLTE cell switching when a formula Mn-hys > Ms + off is satisfied;
wherein hys0 and off0 are initial values, K1 and K2 are correction coefficients, the correction coefficients K1 and K2 are related to the radius of the base station and the moving speed of the terminal, V is the moving speed of the terminal, Mn is the measurement result of the neighboring cell, and Ms is the measurement result of the serving cell.
5. The apparatus of claim 4,
the terminal moving speed obtaining unit is used for obtaining Doppler frequency offset of the terminal in a vehicle and determining the moving speed of the terminal based on the Doppler frequency offset.
6. The apparatus of claim 5,
the terminal moving speed obtaining unit is used for obtaining the terminal moving speed according to a formula
Determining the moving speed V of the terminal;
wherein f isdAnd c is the Doppler frequency offset, c is the electromagnetic wave propagation speed, f is the carrier frequency, and alpha is the included angle between the terminal moving direction and the signal propagation direction.
7. A base station comprising a VoLTE cell switching apparatus as claimed in any of claims 4 to 6.
8. A VoLTE cell switching apparatus, comprising:
a memory; and
a processor coupled to the memory, the processor configured to perform the method of any of claims 1-3 based on instructions stored in the memory.
9. A computer readable storage medium having stored thereon computer program instructions which, when executed by a processor, implement the steps of the method of any one of claims 1 to 3.
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| CN201710510873.0A CN109219091B (en) | 2017-06-29 | 2017-06-29 | VoLTE cell switching method, device and base station |
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