KR101427254B1 - Hand over system by means of pilot beacon, and method the same - Google Patents

Abstract

The present invention discloses a handover system and method over pilot beacons. A handover system for pilot beacons according to the present invention includes a first base station, a first base station and a second base station constituting a base station boundary region, and a mobile station which moves from a first base station to a base station boundary region, A pilot beacon signal is formed on a first frequency among at least two frequencies in use to perform a handover with a mobile station and a frequency shift is performed to a second frequency which is a predetermined traffic frequency among at least two frequencies, And then accepts the call for the mobile station via the second frequency. Therefore, the present invention can perform handover with excellent quality of service without remarkably assigning a frequency to match the frequencies between base stations, and can remarkably reduce a call connection error rate.

Pilot beacon, handover,

Description

[0001] HAND OVER SYSTEM BY MEANS OF PILOT BEACON, AND METHOD THE SAME [0002]

The present invention relates to handover of a mobile communication network, and more particularly, to a handover method of a mobile communication network, which not only smoothly performs hard handover in a mobile communication network through a pilot beacon scheme but also transmits a virtual radio wave coinciding with a radio wave environment around a base station And more particularly, to a handover system and method using a pilot beacon for performing an efficient call connection even when a mobile station tuning to a frequency of a pilot beacon signal inducing a handover occurs.

In the CDMA method, a plurality of channels are used in the same one frequency, and each channel is distinguished using a specific code. The forward link transmitted from the base station to the mobile station includes a pilot, a synchronous, a call, and a call channel. The pilot channel is used for the mobile station to identify the mobile station and identify the base station.

Also, the pilot channel is used as a criterion for determining the coverage of the base station, and the coverage of the base station is determined by the ratio of the signal-to-interference signal of the pilot channel received at the mobile station. This ratio varies depending on the number of users in the call, i.e., the system load. If the load increases, the transmission power of the communication channel increases and the quality of the pilot channel deteriorates and the coverage decreases.

However, when the load decreases, the coverage increases. In addition, the synchronous channel transmits information of the time information and the paging channel. The paging channel is used for call setup and message delivery of the system. Lt; / RTI >

When the capacity of the CDMA system is insufficient, a frequency is additionally allocated to each base station. Therefore, there is a difference in frequency used for each base station.

When a mobile station passes through a boundary area between base stations, a handover is performed to continue a call. In a handover performed in a CDMA system, soft handover applied when the frequencies of the two base stations are the same, There are two types of handover.

When a mobile station using the frequency FA1 moves to a base station having only the frequency FA2, inter-frequency hard handover is performed. In this case, since the mobile station transmits and receives using only the frequency FA1 in the base station boundary region, Can not be captured.

Therefore, a pilot beacon is applied to the mobile station in order to acquire the handover target base station, and the pilot beacon is used only for capturing the handover target base station, but is not used for the actual call.

In more detail, when a mobile station using the frequency 3FA enters the base station boundary region in the CDMA system, the handover target base station that does not use the frequency 3FA generates a pilot beacon signal to radiate the PN signal of the handover target base station After the mobile station forms a pilot channel, it requests handover to the handover target base station.

Thereafter, the CDMA system confirms that the handover target base station uses only 2FA and 1FA excluding the frequency 3FA, and designates either 2FA or 1FA to perform hard handover.

Here, since the CDMA system has a channel list, the mobile stations in the IDLE state tuning in the cell area formed by the base station to be handed over control to make a call only through 2FA and 1FA without tuning to 3FA No problem.

However, since the WCDMA system does not have channel list information, it controls the mobile stations in the IDLE state tuning in the cell area formed by the handover target base station through 2FA and 1FA to set channels through only 2FA and 1FA there is a problem.

One of the reasons for the problem is that in the WCDMA system, the Ec / lo and RSCP values are reported to the FAs having no traffic and the UEs are switched from the coverage of the handover target base stations using only 2FA and 1FA to the power- , There is a problem that the call can not be executed after 3 FAs formed for handover due to the principle of first tuning to FAs with no traffic.

This is the time when measures are needed to overcome these problems.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a pilot beacon handover system and method for smoothly performing hard handover in a mobile communication network through a pilot beacon scheme .

Another object of the present invention is to provide a handover system and method using a pilot beacon for enabling a call connection even if a mobile station tuning to a frequency used for forming a pilot channel by forming a pilot beacon signal occurs There is.

According to an aspect of the present invention, there is provided a pilot beacon handover system including a first base station, a first base station and a second base station forming a base station boundary region, Wherein the second base station forms a pilot beacon signal on a first one of the at least two frequencies to perform a handover with the mobile station, The mobile station receives a call for the mobile station through the second frequency after a frequency transition to a second frequency which is a predetermined traffic frequency among the above frequencies.

Preferably, the second base station copies the first frequency and converts the third frequency to the third frequency when the mobile station is connected to the first base station through a third frequency that is not present in the second base station, And transmitting the pilot beacon signal to the mobile station through the third frequency to form a pilot channel.

Preferably, the second base station forms the handover call through the third frequency, frequency-transitions the third frequency to the first frequency, and re-allocates the frequency to the second frequency .

Preferably, when the second base station allocates the channel to the first frequency or the third frequency to at least one of the mobile stations located in the cell area of the second base station including the mobile station, Or the third frequency is frequency-shifted to the second frequency to perform call connection.

According to a second aspect of the present invention, there is provided a handover target base station including a pilot beacon unit for forming and outputting a pilot beacon signal through a first frequency among at least two frequencies, A handover unit for performing a handover with a mobile station forming a pilot channel in response to a pilot signal, a frequency transition unit for frequency shifting the handed-over call to a second frequency that is a preset traffic frequency among the at least two frequencies, And a call connection for accepting a call to the mobile station via the second frequency.

Preferably, the pilot beacon unit copies the first frequency and converts the third frequency to the third frequency when there is no third frequency used by the mobile station located in the boundary region of the base station among the at least two frequencies, And outputs the pilot beacon signal through a third frequency.

Preferably, the pilot beacon signal includes a CPICH (Common Pilot Channel) signal and a SCH (Synchronization CHannel) signal.

Advantageously, said first frequency is parameterized with a parameter value corresponding to cell selection or cell reselection to a value that does not accommodate said call.

Preferably, the third frequency is equal to the parameter value.

Advantageously, the second frequency is characterized in that a parameter value corresponding to cell selection or cell reselection is parameterized to a value that accepts the call.

Preferably, the parameter value is set through a SIB (System Information Block) value.

Advantageously, the frequency transient unit makes the handover call through the third frequency, frequency-transitions the third frequency to the first frequency, and then recovers the frequency to the second frequency.

Preferably, the frequency transceiver does not request the handover but, when the third frequency is allocated in response to a call connection request from a coverage cell area, the third frequency is allocated to the second frequency Frequency transition.

Advantageously, the frequency shifter frequency-shifts the first frequency to the second frequency when the first frequency is allocated in response to a call connection request from the cell area.

Advantageously, the frequency shifter maintains the second frequency when the second frequency is allocated in response to a call connection request from the cell area.

Preferably, the mobile station performs the handover without switching to a compressed mode (CM) mode for searching for adjacent frequencies in a base station boundary area.

According to a third aspect of the present invention, there is provided a pilot beacon device for a handover target base station in a mobile communication network, the pilot beacon device comprising: A frequency conversion unit for converting the first frequency into a frequency to be handed over to a base station boundary area not included in the at least two frequencies, A beacon signal generator for generating a beacon signal, a digital / analog converter for converting the pilot beacon signal, which is a digital signal, into an analog signal, and an output unit for outputting the pilot beacon signal to the base station boundary area, The first frequency is transmitted via the base station to the at least two Group of frequencies to the set frequency in a second frequency is the frequency shift traffic is characterized by receiving a call to be handed over.

Preferably, the pilot beacon device further includes a gain control unit for controlling the gain of the pilot beacon signal and transmitting the gain to the digital / analog conversion unit, and an amplifying unit for amplifying the pilot beacon signal and transmitting the amplified pilot beacon signal to the output unit .

Preferably, the pilot beacon apparatus further includes a base station connection unit connected to the base station for transmitting / receiving a signal for handover.

A pilot beacon handover method according to a fourth aspect of the present invention for achieving the above object comprises a pilot beacon step of forming and outputting a pilot beacon signal through a first frequency among at least two frequencies, A handover step of performing a handover with the mobile station after a mobile station is located in a mobile station and forming a pilot channel, and performing a frequency transition to a second frequency, which is a preset traffic frequency among the at least two frequencies, And a call connection step for accepting a call to the mobile station via the second frequency.

Preferably, the pilot beacon step includes the steps of: copying the first frequency and converting the third frequency to the third frequency when there is no third frequency used by the mobile station located in the base station boundary region among the at least two frequencies; And outputs the pilot beacon signal through a third frequency.

Preferably, in the case where the first frequency or the third frequency is allocated in response to a call connection request from a coverage cell area, the frequency transition step is not performed when requesting the handover, .

Advantageously, the frequency transition step maintains the second frequency when the second frequency is allocated in response to a call connection request from the cell area.

Therefore, in the present invention, not only the hard handover in the mobile communication network is smoothly performed through the pilot beacon scheme, but also the handover target base station radiating the pilot beacon signal tunes to the frequency of the pilot beacon signal It is possible to perform call connection even when a mobile station occurs, so that it is possible to perform a handover with excellent service quality without additionally allocating a frequency to match the frequencies between base stations and to remarkably reduce the call connection error rate have.

Hereinafter, a preferred embodiment of a pilot beacon handover system according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a handover system using pilot beacons according to an embodiment of the present invention. As shown by way of example only in Fig. 1, a handover system using pilot beacons includes a first base station 100 in which a mobile station 300, a mobile station 300 make a call connection, and a mobile station 300, And a second base station 200 including a base station boundary region with the first base station 100, which is a region in which a positional movement occurs during a call connection with the first base station 100.

Here, since the mobile station 300 performs a handover with the second base station 200, the second base station 200 becomes a handover target base station.

The second base station 200, which is a handover target base station, forms a pilot beacon signal through a first frequency, which is any one of at least two frequencies allocated and used, and transmits the pilot beacon signal to the mobile station 300 And performs handover.

Thereafter, the second base station 200 performs a call connection among the at least two frequencies to frequency-shift to the second frequency, which is a traffic frequency for transmitting and receiving traffic, The mobile station 300 receives the call to the mobile station 300 and completes the handover. Here, a detailed description of the frequency transition process will be described in detail with reference to FIG.

Accordingly, the mobile station 300 also converts the frequency of the connection with the first base station 100 to the second handover completed frequency.

For the sake of a more detailed description, the frequencies used by the first base station 100 are a first frequency, a second frequency and a third frequency, and the frequencies used by the second base station 200 are a first frequency and a second frequency Will be described below.

2 is a conceptual diagram conceptually illustrating the operation principle of the handover system shown in FIG. 2, the handover system based on the pilot beacon includes a first base station 100 and a second base station 100, which are allocated a channel through a third one of the first to third frequencies, Handover to the second base station 200 is performed when the second base station 200 moves to the boundary area of the base station where the second base station 200 is located.

In this process, the mobile station 300 detects the presence of the second base station 200 by capturing the pilot beacon signal emitted by the second base station 200, forms a pilot channel with the second base station 200, Over process is performed.

The pilot beacon signal of the second base station 200 is for forming a pilot channel with the mobile station 300 attempting handover over a third frequency that is not present in the second base station 200, Performs a frequency-to-frequency conversion and then a frequency-shifted third frequency.

The pilot beacon signal includes a CPICH (Common Pilot Channel) signal and a SCH (Synchronization CHannel) signal.

Here, since the third frequency is formed by being copied after the first frequency is copied, the parameter value set at the first frequency is mostly maintained. Thereby, when the parameter value corresponding to the cell selection or cell reselection of the first frequency is set to a value not accepting the call, the third frequency also maintains the same parameter value.

For example, a parameter value corresponding to cell selection or cell reselection may be set through a SIB (System Information Block) value.

Further, the second base station 200 performs handover to the mobile station 300 through the third frequency, and then frequency-transverses the third frequency, which is the frequency of the handed-over call, to the first frequency, which is the frequency before the demodulation, The mobile station 300 receives the call to the mobile station 300 and recovers the frequency to a second frequency that is a predetermined frequency for traffic transmission.

Thereafter, the second base station 200 causes the mobile station 300 to perform a call connection through the second frequency that has undergone the last frequency transition so as to continue the call connection.

Meanwhile, the second base station 200 may have a case where another mobile station 300 in the IDEL state performs call connection in the cell area formed by the second base station 200, and the system principle of first tuning to the frequency without traffic A third frequency, which is a virtual radio wave for handover, occurs.

Even in such a case, the third frequency may be changed to a second frequency according to a preset frequency, without accepting the call, according to the fact that the third frequency is a duplicated parameterized first frequency so as not to accommodate the call, do.

Also in this case, it is preferable that the third frequency is transited to the first frequency, which is the frequency before the demodulation, and then the transited first frequency is reassigned to the predetermined second frequency for traffic transmission.

Similarly, when there is a mobile station 300 attempting to establish a call to a first frequency, the mobile station 300 transitions to the second frequency and makes a call connection through the second frequency.

3 is a configuration diagram of the second base station 200 shown in FIG. 3, the second base station 200, which is the handover target base station, copies the first frequency and then converts the third frequency to a third frequency and outputs the pilot beacon signal using the third frequency A handover unit 220 for performing a handover by forming a pilot channel with the mobile station 300, a handover unit 220 for handing over a call handed over the third frequency to a second frequency And a call connection 240 for accepting a call to the mobile station 300 over a second frequency set to receive the call to maintain a call connection.

In this case, the mobile station 300 responds to the control execution of the mobile communication system and the second base station 200 in a state in which the mobile station 300 is not switched to the CM (Compressed Mode) mode for searching for adjacent frequencies, And performs handover.

As described above, the frequency shifter 230 frequency-shifts the third frequency to the first frequency, which is the frequency before the demodulation, and then transmits the frequency-shifted first frequency to the second frequency It is preferable that the frequency is recapitulated in the frequency.

In addition, when a second frequency is allocated in response to a call connection request from a mobile station 300 located in a cell region formed by the second base station 200, the frequency transceiver 230 maintains a second frequency Perform call connection.

4 is a configuration diagram of the pilot beacon unit shown in FIG. 4, the pilot beacon unit constituting the pilot beacon unit 210 is provided in the second base station 200, which is the base station to be handed over, and the pilot beacon unit in the first base station 200, which is used in the second base station 200, A frequency copying unit 211 for copying a predetermined first frequency from the second base station 200 to perform a handover between the first frequency and the second frequency, A beacon signal generator 213 for generating a pilot beacon signal on the basis of the third frequency that has been demodulated, a pilot signal generator 213 for converting the pilot beacon signal, which is a digital signal, into an analog signal, And an output unit 217 for radiating the pilot beacon signal to the base station boundary area formed by the first base station 100 and for allowing the mobile station 300 to receive the pilot beacon signal All.

The pilot beacon apparatus 210 further includes a gain control unit 215 for controlling the gain of the pilot beacon signal, an amplification unit 216 for amplifying the generated pilot beacon signal, A base station connection unit 218 for connection to the base station 218, and the like.

FIG. 5 is a flowchart illustrating an operation procedure of the handover system shown in FIG. 1. FIG. 4, the handover method using the pilot beacon is performed by the first base station 100 while the mobile station 300 makes a call connection with the first base station 100 through the third frequency, The pilot beacon signal is transmitted from the second base station 200 to the base station boundary region between the first base station 200 and the second base station 200 (S1 to S5).

After that, the second base station 200 forms a pilot channel with the mobile station 300 (S7 and S9), and then, in response to the handover request of the mobile station 300, a process of allocating a corresponding frequency channel (S13 and S15), and then transmits a channel assignment message to the mobile station 300 to inform the mobile station 300 that it is allocated to the second frequency (S17).

Here, as mentioned above as a preferred example in the above description, the frequency transition process frequency-shifts the third frequency for the head over operation to the first frequency, which is the frequency before the demodulation, and then transmits the first frequency, And a frequency recapture process is performed at the set second frequency.

The mobile station 300 receiving the channel assignment message switches to the second frequency (S19), terminates the handover with the second base station 200, and continues the call connection through the second frequency (S21).

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims It can be understood that

The present invention also relates to a method and apparatus for smoothly performing hard handover in a mobile communication network through a pilot beacon scheme and also for transmitting a virtual airwave that matches the propagation environment around the base station, It is an invention that is industrially applicable because it is intended to perform an efficient call connection even when a synchronizing mobile station occurs, and is not only a possibility of commercialization or sales, but also can be practically and practically carried out.

1 is a block diagram of a handover system using pilot beacons according to an embodiment of the present invention;

FIG. 2 is a conceptual diagram conceptually illustrating the operation principle of the handover system shown in FIG. 1;

FIG. 3 is a configuration diagram of the second base station shown in FIG. 1,

4 is a configuration diagram of the pilot beacon portion shown in Fig. 3, and Fig.

FIG. 5 is a flowchart illustrating an operation procedure of the handover system shown in FIG. 1. FIG.

Description of the Related Art

100: first base station 200: second base station

210: pilot beacon unit 211: frequency copy unit

212: frequency shifter 213: beacon signal generator

214: D / A conversion unit 215: gain adjustment unit

216 amplifying unit 217 outputting unit

218: base station connection unit 220: handover unit

230: frequency shifter 240: arc connection

300: mobile station

Claims (23)

In a handover system of a mobile communication network, A first base station; A second base station forming a boundary region between the first base station and the base station; And And a mobile station that moves from the first base station to the base station boundary region, The second base station, A pilot beacon signal is formed through a first one of at least two frequencies to perform a handover with the mobile station, and the handover is performed on a frequency that is a second frequency that is a predetermined traffic frequency of the at least two frequencies, And receives a call to the mobile station over the second frequency after transition. 2. The method of claim 1, wherein the second base station Wherein the mobile station copies the first frequency to the third frequency when the mobile station is connected to the first base station via a third frequency that is not present in the second base station, Signal to the mobile station to form a pilot channel. 3. The method of claim 2, wherein the second base station Wherein the handover is performed through the third frequency, and after the third frequency is frequency-shifted to the first frequency, the mobile terminal recovers the frequency to the second frequency. 3. The method of claim 2, wherein the second base station Wherein when allocating a channel to the first frequency or the third frequency to one or more mobile stations including the mobile station and located in a cell region of the second base station, Wherein the mobile station performs a frequency-to-frequency transition and performs a call connection with the pilot beacon. In a handover target base station of a mobile communication network, A pilot beacon for forming and outputting a pilot beacon signal through a first one of at least two frequencies; A handover unit for performing a handover with a mobile station forming a pilot channel in response to the pilot beacon signal; A frequency transition unit for frequency shifting the call to be handed over to a second frequency which is a preset traffic frequency among the at least two frequencies; And And a call connection for accepting a call to the mobile station over the second frequency. 6. The apparatus of claim 5, wherein the pilot beacon portion The first frequency is copied to the third frequency and the pilot beacon signal is transmitted through the third frequency when the mobile station located in the base station boundary region of the at least two frequencies does not have a third frequency used by the mobile station And outputs the handover target base station. 6. The method of claim 5, wherein the pilot beacon signal A Common Pilot Channel (CPICH) signal, and a Synchronization CHannel (SCH) signal. 7. The method of claim 6, wherein the first frequency is A parameter value corresponding to cell selection or cell reselection is parameterized to a value that does not accommodate the call. 9. The method of claim 8, wherein the third frequency is And the parameter value is equal to the parameter value. 6. The method of claim 5, wherein the second frequency is Wherein a parameter value corresponding to cell selection or cell reselection is parameterized to a value that accepts the call. 11. A method as claimed in any one of claims 8 to 10, Wherein the handover target base station is set through a SIB (System Information Block) value. 7. The apparatus of claim 6, wherein the frequency transient section Wherein the handover target base station makes a call to be handed over the third frequency, and frequency-reassigns the third frequency to the first frequency and then to the second frequency. 7. The apparatus of claim 6, wherein the frequency transient section Wherein the third frequency is frequency-shifted to the second frequency when the third frequency is allocated in response to a call connection request from a coverage cell region, instead of requesting the handover. Over object base station. 14. The apparatus of claim 13, wherein the frequency transient section And when the first frequency is allocated in response to a call connection request from the cell area, the first frequency is frequency-shifted to the second frequency. 14. The apparatus of claim 13, wherein the frequency transient section And maintains the second frequency when the second frequency is allocated in response to a call connection request from the cell area. 6. The mobile station of claim 5, Wherein the mobile station performs the handover without switching to a compressed mode (CM) mode for searching for an adjacent frequency in a base station boundary area. 1. A pilot beacon device in a handover target base station of a mobile communication network, A frequency copying unit for copying a first frequency that is a frequency for performing handover among at least two or more frequencies corresponding to the base station; A frequency shifter for shifting the first frequency to a handover frequency of a base station boundary area not included in the at least two frequencies; A beacon signal generating unit for generating a pilot beacon signal based on the frequency to be demodulated; A digital / analog converter for converting the pilot beacon signal, which is a digital signal, into an analog signal; And And an output unit for outputting the pilot beacon signal to the base station boundary area, Wherein the first frequency is selected from the group consisting of: Wherein the base station receives a call to be handed over to a second frequency that is a preset traffic frequency among the at least two frequencies through the base station. 18. The apparatus of claim 17, wherein the pilot beacon device A gain controller for adjusting a gain of the pilot beacon signal and transmitting the gain to the digital / analog converter; And And an amplifier for amplifying the pilot beacon signal and transmitting the amplified pilot beacon signal to the output unit. 19. The apparatus of claim 17 or 18, wherein the pilot beacon device And a base station connection unit connected to the base station for transmitting / receiving a signal for handover. A handover method of a mobile communication network, A pilot beacon step of forming and outputting a pilot beacon signal through a first frequency among at least two frequencies; A handover step of performing a handover with the mobile station after a mobile station is located in a base station boundary region to form a pilot channel; A frequency transition step of frequency shifting the handed-over call to a second frequency which is a predetermined traffic frequency among the at least two frequencies; And And a call connection step for accepting a call to the mobile station over the second frequency. 21. The method of claim 20, wherein the pilot beacon step Wherein the mobile station copies the first frequency to the third frequency when there is no third frequency used by the mobile station located in the base station boundary region among the at least two frequencies, And outputting the pilot beacon. 22. The method of claim 21, Wherein the mobile station transitions to the second frequency when the first frequency or the third frequency is allocated in response to a call connection request from a coverage cell region, instead of requesting the handover. The handover method through 23. The method of claim 22, And when the second frequency is allocated in response to a call connection request from the cell area, the second frequency is maintained.

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