KR100654374B1 - Base station apparatus for mobile communication system, method of transmitting and receiving data and method of hand-off using the beacon signal for mobile communication system - Google Patents

Abstract

The present invention outputs one or more frequency domain signals allocated from a plurality of frequency domains through a base station transmitter, and outputs one or more frequency domain signals that are not assigned through a base station beacon frequency transmitter. Apparatus, in particular, a base station for controlling to output the frequency domain signal through the base station beacon frequency transmitter when a transmitter in the frequency domain transitions to an abnormal state among the frequency domain signals output through the base station transmitter It characterized in that it comprises a processor.

Frequency Domain, Beacon, Transmitter, Main Processor, Base Station

Description

BASE STATION APPARATUS FOR MOBILE COMMUNICATION SYSTEM, METHOD OF TRANSMITTING AND RECEIVING DATA AND METHOD OF HAND-OFF USING THE BEACON SIGNAL FOR MOBILE COMMUNICATION SYSTEM}

1 is a diagram illustrating a base station handoff having a different frequency according to the prior art.

2 is a view showing the concept of a hard handoff using a beacon signal in accordance with the present invention.

3 is a block diagram showing the configuration of a base station apparatus for transmitting and receiving data using a beacon signal according to an embodiment of the present invention.

4 is a flowchart illustrating a handoff procedure using a beacon signal according to an embodiment of the present invention.

5 is a flowchart illustrating a handoff procedure between base stations in the same control station according to the first embodiment of the present invention.

6 is a flowchart illustrating an inter-base station handoff procedure of another control station according to the second embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

300: base station 310: base station main processor

311: state management unit 312: configuration management unit

313: shape control unit 320: base station transmitter

330: base station beacon FA transmitter

The present invention relates to an apparatus and method for handoff a mobile terminal in a mobile communication system, and more particularly, to an apparatus and method for handoff using a beacon signal between base stations having different frequencies.

Since the cellular cellular mobile telecommunication system was developed in the United States in the late 1970s, AMPS (Advanced Mobile Phone Service), which can be called the analog 1st generation (1G) mobile communication system in Korea, Began to provide voice communication services. Since then, the 2nd generation (2G) mobile communication system has been launched and commercialized in the mid-1990s, and the IMT, a 3rd generation (3G) mobile communication system, aimed at improved wireless multimedia and high-speed data services in the late 1990s. -2000 (International Mobile Telecommunication-2000) has been commercialized and operated in part.

Currently, the 3G mobile communication system is developing into a 4G (4th Generation) mobile communication system. The fourth generation mobile communication system is not only a simple wireless communication service like the previous generation mobile communication systems, but also aims at efficient interworking and integration services between a wired communication network and a wireless communication network and is faster than the third generation mobile communication system. Techniques for providing data transmission services are being standardized.

As is well known, in a code division multiple access (hereinafter referred to as "CDMA") system of a mobile communication method for wireless communication between mobile communication terminals, frequency allocation according to a plurality of sectors between base stations having different frequencies. (Frequency Allocation or Frequency Assignment; FA) method, in order to secure the mobility of the mobile terminal is performed to perform a smooth handoff between the base station, this handoff function during the call setup attempt of the mobile terminal This is to prevent call establishment failure due to the mobility of the terminal.

Meanwhile, in order to smoothly perform handoff between base stations of the CDMA system, overhead channels (ie, pilot channels, sync channels, and paging channels) for a plurality of frequencies may be used. A beacon signal is included. The beacon signal is generated by modulating an RF signal while periodically changing a frequency of a radio frequency (RF) carrier.

1 is a diagram showing a base station handoff having a different frequency according to the prior art. As described above, in the CDMA system, different frequency allocations or sector allocations can be performed between base stations. Referring to FIG. 1, the base station A 100 operates a three sector / 3 FA method, and the base station B 110, which is an adjacent base station of the base station A 100, uses a three sector / 6 FA method. can do. In this case, the FA is a term used in a base station / relay system and refers to an assigned channel frequency unit. For example, in the case of the PCS-type CDMA, a total of 21 channels are allocated to a 30 MHz bandwidth (BW), each of 1.25 MHz per channel, and a unit of one channel is called FA.

On the other hand, when the mobile terminal wants to handoff from base station B 110 to base station A 100, the service frequencies of base station B 110 are six (111, 112, 113, 114, 115, 116), Since the service frequencies of the base station A 100 are three (103, 104, 105), some of the frequencies used by the base station B (110) cannot be used in the base station A (100). That is, even if three mobile stations 103, 104, and 105 are commonly used by the base station A 100 and the base station B 110, the mobile terminal handoffs from the base station B 110 to the base station A 100. Soft handoff (Soft H / O) is possible. However, when handing off from base station B 110 to base station A 100 at a frequency not used by base station A 100 (that is, the remaining three FAs 101, 102, 103), soft handoff is performed. Can't be.

Accordingly, at this time, the base station A 100 broadcasts a beacon signal to the remaining three FAs 101, 102, and 103 to support hard H / O between frequencies. Done. Terminal users in the area, centered on a base station, can make calls through frequency allocation (FA channel). Of course, the greater the number of FAs, the more money you can handle. In addition, as the call volume increases, more FAs are required, which in turn requires more base stations. However, the additional base station installation is a great cost burden for the operator, especially in the area where the call volume is not required is not very much installed.

On the other hand, when there is a difference in call volume according to regions around each base station, that is, when moving from a lot of FA to a small region as shown in FIG. 1, a problem of call quality occurs. In this case, the pilot beacon signal is a signal for stabilizing the call quality by smoothly connecting the FAs. Accordingly, the terminal receiving the pilot beacon signal attempts to connect the call by switching the FA by itself.

However, in this case, if the transceiver (XCVR) of the base station A (100) is abnormal, the call service of the transmit / receive frequency signal used by the transceiver cannot be performed, and thus a pilot strength measurement message (hereinafter, referred to as a pilot strength measurement message; , It is called 'PSMM'). The PSMM determines whether to handoff to another neighboring base station by the pilot reception sensitivity of the corresponding base station as a message confirming the channel state between the base station and the terminal. Therefore, when the PSMM message cannot be processed normally due to the abnormal state of the XCVR, a problem arises in that it is impossible to properly cope with a call that is handed off from another base station or cell.

Accordingly, an object of the present invention is to provide a hard handoff apparatus and method using a beacon signal in a mobile communication system that enables smooth handoff by broadcasting a frequency signal in an abnormal transceiver using a beacon signal.

An apparatus of the present invention for achieving the above object is a base station apparatus of a mobile communication system, a base station transceiver for transmitting and receiving signals in a plurality of frequency domains supported by the base station, a base station beacon frequency transmitter for transmitting a beacon signal, and the base station A base station main processor that monitors the state of the transceiver for each frequency domain and controls the output of the signal in each frequency domain, and outputs and assigns the signals in the frequency domain among the plurality of frequency domains through the base station transceiver. Signals in the non-frequency domain are output through the base station beacon frequency transmitter, and if a frequency domain in which the transceiver transitions to an abnormal state occurs among the frequency domains output through the base station transceiver, the signal in the corresponding frequency domain is output. base It is characterized in that the control to output through the station beacon frequency transmitter.

The method of the present invention for achieving the above object is outputted through the base station transceiver for the signals in the frequency domain of the plurality of frequency domains and through the base station beacon frequency transmitter for signals in the unassigned frequency domain A method of transmitting and receiving data using a beacon signal in a base station of a mobile communication system, the method comprising: monitoring a state of a base station transceiver for each frequency region, and controlling signal transmission for a corresponding frequency region according to the monitoring result And, if it is determined that the base station transceiver has transitioned to an abnormal state according to the monitoring result, controls the base station transceiver to output a signal of a frequency domain transitioned to an abnormal state through the base station beacon frequency transmitter. do.

In addition, the handoff method of the present invention for achieving the above object; A handset in a base station of a mobile communication system that outputs one or more frequency domain signals allocated from a plurality of frequency domains through a base station transmitter and outputs one or more frequency domain signals that are not assigned through a base station beacon frequency transmitter. CLAIMS 1. A method of off, comprising: a mobile terminal sending a pilot strength measurement message (PSMM) according to pilot signal measurement to a control station; Determining whether to handoff the mobile terminal according to the received pilot strength measurement message; And performing a handoff by using a beacon signal that transmits a signal for a corresponding frequency when the frequency state of the target base station to be handed off is abnormal.

Hereinafter, a detailed description of a preferred embodiment of the present invention will be described with reference to the accompanying drawings. In the following description, detailed descriptions of well-known functions or configurations will be omitted when it is determined that the detailed descriptions of the known functions or configurations may unnecessarily obscure the subject matter of the present invention.

When the XCVR of the base station transitions to an abnormal state in the CDMA system, the transmission of the transmission signal is stopped so as not to perform transmission / reception signal processing through the corresponding XCVR, and at the same time, the transmission frequency signal transmitted from the XCVR transmits the beacon signal. By using the transmission to provide a smooth handoff between base stations.

In addition, the present invention provides a smooth handoff (i.e., hard handoff) to another serviceable FA by transmitting a beacon signal for sending a PSMM of the XCVR in case of a handoff service request flowing into the XCVR in an abnormal state. Make it possible.

2 is a view showing the concept of a hard handoff using a beacon signal according to the present invention. Referring to FIG. 2, when a mobile terminal wants to handoff from base station B 110 to base station A 100, it can be handed off to another FA using a beacon signal. That is, a mobile terminal that is used by base station B 110 but communicates by three FAs 101, 102, 103 that is not used by base station A 100 is transferred from base station B 110 to base station A 100. When handing off, base station A 100 transmits a beacon signal to three FAs 101, 102, and 103 that are not used by base station A 100, i.e., other FAs available to base station A 100 (i.e. , 104 or 105 or 106).

On the other hand, if the XCVR corresponding to any one of the FAs used in the base station A (100) or the base station B (110) transitions to an abnormal state, handoff to the corresponding FA (soft handoff or hard). Handoff) cannot be performed normally. Therefore, the XCVR which has transitioned to the abnormal state according to the present invention stops the transmission of the transmission signal so that the corresponding XCVR cannot perform the transmission / reception signal processing and simultaneously transmits the transmission frequency signal transmitted from the XCVR using the beacon signal. Be sure to That is, the beacon signal is used to transmit not only the frequency signal not originally used, but also the frequency signal when the supportable frequency signal becomes abnormal.

In addition, when a handoff service request to the XCVR in the abnormal state occurs, by sending a PSMM of the FA by a beacon signal, it is possible to normally handoff (ie, hard handoff) to another serviceable FA.

Hereinafter, an example of an apparatus and method according to the inventive concept described above with reference to FIGS. 3 and 4 will be described.

3 is a block diagram showing the configuration of a base station apparatus for transmitting and receiving data using a beacon signal according to an embodiment of the present invention.

Referring to FIG. 3, the base station apparatus 300 according to an embodiment of the present invention includes a base station main processor 310 including a state manager 311, a configuration manager 312, and a shape controller 313. A base station transmitter 320 for transmitting a frequency signal that can be supported by the base station and a base station beacon FA transmitter 330 for transmitting a beacon signal according to the present invention.

The configuration of the base station apparatus 300 for the implementation of the present invention has a function of monitoring the state of the XCVR in the base station, the function of blocking the transmission path of the XCVR when the state of the XCVR abnormally transitions, and beacons The FA may be classified into a function for requesting transmission of a transmission signal of the corresponding XCVR.

In more detail, the state management unit 311 of the base station main processor 310 performs a function of periodically monitoring the state of each XCVR for each FA through the base station transmitter 320. At this time, if the state management unit 3110 detects that the abnormal state of the XCVR for a specific FA, or the normal state of the call service due to the problem of the system reference clock, the base station transmitter 320 in accordance with the present invention Stops transmission of the transmission signal of the corresponding FA. On the other hand, when the XCVR transitions to the normal state again, it controls to resume transmission of the transmission signal of the corresponding FA.

In addition, the state manager 311 requests the configuration manager 312 to change the output frequency setting information of the beacon FA according to the state of the XCVR. That is, when the XCVR for a specific FA transitions to an abnormal state, the beacon transmits a signal for the corresponding FA. In addition, the state management unit 311 controls the shape control unit 313 to request the frequency setting of the beacon FA according to the base station configuration information of the configuration management unit 312.

Therefore, when the transmission signal transmission of the XCVR is due to an abnormality of the XCVR, the shape control unit 313 processes the base station beacon FA transmitter 330 to transmit the corresponding XCVR transmission frequency signal at the request of the state management unit 311. do. On the other hand, when the state of the XCVR transitions from an abnormal state to a normal state, since the XCVR can transmit the original signal frequency, it is preferable to stop the transmission through the beacon FA.

4 is a flowchart illustrating a hard handoff procedure using a beacon signal according to an embodiment of the present invention.

Referring to FIG. 4, first, the base station periodically monitors the state of the transceiver (step 401). At this time, if it is determined that the XCVR for the particular FA is abnormal (step 402), the transmission of the transmission signal to the transceiver is stopped (step 403) according to the present invention. Then, it transmits the corresponding transceiver frequency by the beacon (step 404). On the other hand, if the transceiver for each XCVR is normal as a result of the monitoring, the transmission signal is normally transmitted through the transceiver of the corresponding FA (step 407).

On the other hand, when the handoff situation occurs in the abnormal state in the corresponding XCVR (step 405), even if the mobile station using the same frequency in the other base station can not use the frequency, the beacon signal according to the present invention In step 406, a hard handoff is performed between FAs.

That is, even if the FA used by the base station before the handoff is the same FA used by the base station to be handed off, if the XCVR for the corresponding FA is not in a normal state, the hard hand is moved to another available FA by the beacon signal according to the present invention. Turned off.

Hereinafter, procedures for performing handoff between base stations according to embodiments of the present invention will be described with reference to FIGS. 5 and 6. First, a handoff procedure between base stations belonging to the same control station will be described with reference to FIG. 5, and a handoff procedure between base stations belonging to different control stations will be described with reference to FIG. 6.

5 is a flowchart illustrating a handoff procedure between base stations in the same control station according to the first embodiment of the present invention.

Referring to FIG. 5, when an abnormal FA occurs in a handoff procedure between base stations in the same control station, the hard handoff is performed to another FA available to the control station according to the present invention.

First, a mobile station (hereinafter referred to as 'MS') transmits a PSMM signal according to a pilot signal measurement to a selection / distribution unit (hereinafter referred to as 'SDU') of a control station. Step 501). The SDU reports the received PSMM to the call control processor (hereinafter referred to as 'CCP') of the control station (step 502). The CCP checks the received PSMM and determines whether to handoff the MS. Then, the CCP transmits a response message (PSMM Ack.) Signal for reporting the PSMM to the SDU (step 503).

Meanwhile, the CCP satisfies the handoff condition set using the Neighbor Active Pilot Set for the neighbor base station, and performs handoff from the base station B (ie, serving base station) to the base station A (ie, target base station). If so, a handoff request message (Handoff Req.) Requesting a handoff for the MS is transmitted (step 504) to the base station A to be handed off. In this case, if the FA to be handoff of the base station A is abnormal and the beacon FA is used according to the present invention, the soft handoff to the corresponding FA cannot be performed and the hard hand to another available FA. Will require an off. Therefore, according to the present invention, the handoff time can be shortened.

At this time, the handoff request message (Handoff Req.) Is also transmitted to the base station B, which is the base station before the handoff of the MS (step 505). Here, base station A serving as the serving base station and base station B serving as the target base station respectively transmits a handoff response message (Handoff Rsp.) To the CCP as a response to the handoff request message (steps 506 and 507).

Upon receipt of the handoff response message, the CCP transmits a handoff direction message (MDM) to the SDU (step 508). The SDU having received the handoff indication message from the CCP transmits a handoff indication message to the corresponding MS (step 509) to allow the MS to perform a handoff procedure. After receiving the handoff indication message from the SDU, the MS performs a handoff and transmits a handoff completion message (HCM) indicating that the handoff is completed to the SDU (step 510). The SDU receives a handoff complete message from the MS and transmits a handoff complete message to the CCP (step 511) to complete the handoff procedure.

That is, in the handoff procedure between base stations belonging to the same control station, if the corresponding FA in the base station to be handed off is abnormal, processing is performed so that the hard handoff can be performed to the FA available through the beacon signal according to the present invention. Done.

6 is a flowchart illustrating an inter-base station handoff procedure of another control station according to the second embodiment of the present invention.

Referring to FIG. 6, in a handoff procedure between base stations of another control station, a handoff request method varies according to whether a control station managing a base station to be handed off checks the steady state of a corresponding FA output. That is, when the control station of the base station to be handoff confirms that the FA output of the base station is normal, the soft handoff is performed, and the beacon FA is used according to the present invention because the FA output of the base station is abnormal. If it is confirmed, the hard handoff to another FA is performed. On the other hand, when the control station of the base station to be handed off does not determine whether the FA output of the base station is XCVR or beacon, it is preferable to first request a soft handoff to the same FA.

First, the MS transmits the PSMM signal according to the pilot signal measurement to the control station B (that is, the SDU and the CCP of the control station B) managing the base station B serving as the serving base station (step 601).

On the other hand, the control station B satisfies the handoff condition set using the Neighbor Active Pilot Set for the neighboring base station, and is handed from the base station B (ie, serving base station) to the base station A (ie, target base station). If it is determined to turn off, a handoff request message (Handoff Req.) Is transmitted to the base station B, which is the base station, before handoff of the MS (step 602).

Also, the base station A to be handed off transmits a handoff request message (Handoff Req.) Requesting a handoff to the MS. In this case, when the base station A to be handed off is a control station A which is another control station instead of the control station B which manages the serving base station B, the handoff request message is first transmitted to the control station A that manages the base station A which is the target base station. Transmission (step 603).

Meanwhile, when the control station A recognizes that the output of the FA to be handed off from the base station B of the control station B uses the beacon FA at the base station A according to an embodiment of the present invention, the base station A causes the hard hand between the FAs to be directly handed. Will be required to perform the off. In addition, when the base station A recognizes that the output of the FA to be handoff is an FA normally using the XCVR, the base station A is required to perform a soft handoff according to a general procedure.

On the other hand, when the control station A does not know whether the output of the FA to be handed off from the base station B of the control station B according to the embodiment of the present invention is the XCVR or the beacon FA at the base station A, the soft handoff is preferentially performed. It is desirable to require a soft handoff first, as this is more effective.

When the handoff to be performed by the MS is determined to be a hard handoff, a hard handoff is requested to the base station A (step 604). When the handoff is determined to be soft handoff, the soft handoff is normally soft according to the service state of the corresponding FA. It is determined whether to perform a handoff or a hard handoff in accordance with the present invention.

That is, in the case of the soft handoff, when the FA is normally in a serviceable state, the base station A transmits a handoff response message to the control station A (step 605). The control station A sends a handoff response message to the control station B (step 606) to process hard handoff between FAs.

Accordingly, the control station B receives a handoff response message (Handoff Rsp.) From the base station A, the serving base station, and the base station B, respectively (steps 606 and 607).

Upon receipt of the handoff response message, the control station B transmits a handoff indication message (MDM) to the corresponding MS (step 608) to perform a handoff according to the determined handoff scheme. Do it. After receiving the handoff indication message from the control station B, the MS performs a handoff and sends a handoff completion message (HCM) to the control station B indicating that the handoff is completed (step 609). The procedure is complete.

That is, in the handoff procedure between base stations belonging to different control stations, whether to perform soft handoff or hard handoff is determined according to whether the corresponding FA status is checked at the base station to be handed off.

On the other hand, in the embodiment of the present invention has been described with respect to specific embodiments, of course, various modifications are possible without departing from the scope of the invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the appended claims, but also by those equivalent to the claims.

According to the present invention, in case of abnormal operation of the XCVR due to the problem of the base station system, the base station itself processes the transmission of the transmission signal using the beacon FA, thereby ensuring the continuity of handoff calls of other base stations or cells. In this case, since the base station performs its own function, there is an advantage in that call continuity can be guaranteed without the operator's intention.                     

In addition, when the status of the service FA of the target base station is normal, soft handoff or hard handoff should be performed. However, when using the beacon FA according to the present invention, the hard hand between FAs is directly related to the service FA state of the target base station. By performing the off, there is an advantage that the time required for handoff can be shortened.

Through the beacon signal processing and handoff method according to the present invention as described above it is possible to achieve the optimization of the base station operation and to prevent the degradation of the call quality.

Claims (16)

A base station apparatus of a mobile communication system, A base station transceiver for transmitting and receiving signals in a plurality of frequency domains supported by the base station, A base station beacon frequency transmitter for transmitting a beacon signal, and Including a base station main processor for monitoring the state of the base station transceiver for each frequency domain and controls the output of the signal of each frequency domain, Among the plurality of frequency domains, the signal in the allocated frequency domain is output through the base station transceiver, and the signal in the unassigned frequency domain is output through the base station beacon frequency transmitter,  A mobile communication system, characterized in that for controlling the output of the signal in the frequency domain through the base station beacon frequency transmitter when the frequency domain to which the transceiver transitions to an abnormal state occurs among the frequency domains output through the base station transceiver. Base station apparatus. The method of claim 1, wherein the base station main processor, A state management unit for monitoring a state of a transceiver for each frequency region; A configuration manager configured to control a beacon transmitter to output a signal transmission for a corresponding frequency range when the transceiver for a specific frequency region transitions to an abnormal state according to the monitoring result of the state management unit; And And a configuration management unit for requesting the frequency setting of the beacon signal according to the configuration information of the base station configuration of the configuration management unit. The base station apparatus of claim 1, wherein the monitoring of the state-by-frequency transceiver is periodically performed. The base station of claim 1, wherein when a frequency domain in which the transceiver transitions to an abnormal state occurs among frequency regions output through the base station transceiver, the base station stops transmitting a signal in a frequency domain in which the base transceiver station transitions to an abnormal state. A base station apparatus of a mobile communication system, characterized in that for controlling a transceiver. The base station of the mobile communication system according to claim 1, wherein the base station of the mobile communication system is controlled to transmit a signal in the frequency domain through a transmitter when the transceiver transitions back to a normal state with respect to a frequency region in which the transceiver is transitioned to an abnormal state. Device. delete Data using the beacon signal in the base station of the mobile communication system for outputting the signals in the frequency domain of the plurality of frequency domains through the base station transceiver and the signals in the unassigned frequency domain through the base station beacon frequency transmitter In the method for transmitting and receiving, Monitoring the state of the base station transceiver for each frequency region, and Controlling signal transmission for a corresponding frequency range according to the monitoring result; And if it is determined that the base station transceiver has transitioned to an abnormal state according to the monitoring result, the base station transceiver controls the base station beacon to transmit a signal in a frequency domain transitioned to an abnormal state through the base station beacon frequency transmitter. A method of transmitting and receiving data using a beacon signal in a base station of the system. The method of claim 7, wherein the monitoring of the base station transceiver for each frequency domain is periodically performed. 8. The method of claim 7, wherein if it is determined that the base station transceiver has transitioned to an abnormal state according to the monitoring result, the base station transceiver is controlled so that the base station transceiver stops transmitting the signal in the frequency domain transitioned to an abnormal state. A method of transmitting and receiving data using a beacon signal in a base station of a mobile communication system. The beacon signal of the base station of the mobile communication system according to claim 7, wherein if it is determined that the base station transceiver has transitioned back to a normal state according to the monitoring result, the base station of the mobile communication system controls to transmit a signal of a corresponding frequency range through a transmitter. Data transmission and reception method using. A handset in a base station of a mobile communication system that outputs one or more frequency domain signals allocated from a plurality of frequency domains through a base station transmitter and outputs one or more frequency domain signals that are not assigned through a base station beacon frequency transmitter. In the off method, Sending, by the mobile terminal, a pilot strength measurement message (PSMM) according to the pilot signal measurement to the control station; Determining whether to handoff the mobile terminal according to the received pilot strength measurement message; And Performing a handoff using a beacon signal that transmits a signal for a corresponding frequency when a frequency state of a target base station to be handed off is abnormal; handoff at a base station of a mobile communication system Way. 12. The method of claim 11, wherein when the handoff is a handoff between base stations belonging to the same control station, the handoff is performed by a hard handoff method. 12. The method of claim 11, wherein when the handoff is a handoff between base stations managed by different control stations, a method of performing handoff is determined according to whether a corresponding frequency state is checked at the base station to be handed off. A handoff method in a base station of a mobile communication system. 15. The method of claim 13, wherein if it is recognized that the beacon signal is used for the output of the corresponding frequency of the base station to be handed off, the handoff method in the base station of the mobile communication system is performed. . 15. The method of claim 13, wherein if the output of the corresponding frequency of the base station to be handed off uses a normal transceiver, a soft handoff procedure is performed. 15. The method of claim 13, wherein if the output of the corresponding frequency of the base station to be handed off whether the use of a normal transceiver or a beacon signal is unknown, the soft handoff procedure is performed. Handoff method.

Images