KR20000075204A - apparatus and method for implementing hand-off in mobile communication system having short sync channel - Google Patents

Abstract

PURPOSE: A hand-off operation apparatus of a mobile communication system having a short synchronous channel and a method of the same are provided for using a forward single synchronous channel which is capable of generating a PN_OFFSET signal. CONSTITUTION: A controller(101) performs a function for enabling and disabling the operations of each channel generator of a base station, processing a message of a physical layer transmitted from the base station and communicating a message with an upper level hierarchy. A pilot channel generator(103), a synchronous channel generator(104), a short synchronous channel generator(105) and a paging channel generator(106) generate a common channel information which are commonly used by the users of one channel or a plurality of channels. An exclusive control channel generator(102), a basic channel generator(107) and an additional channel generator(108) generate a subscriber exclusive channel information which is allocated differently for each user.

Description

Apparatus and method for implementing hand-off in mobile communication system having short sync channel}

The present invention relates to an apparatus and method for performing handoff in a mobile communication system, and more particularly, to an apparatus and method for handoff that occurs when a mobile station moves from an asynchronous mobile communication system to a synchronous mobile communication system.

The asynchronous mobile communication system may be, for example, UMTS adopted by the European standard method, and the synchronous mobile communication system may be IMT2000 adopted by the US standard method. Currently, the two systems are harmonized, and accordingly, various technologies for making the two systems compatible are required. One of them is a technique for handoff that can occur between two systems.

In general, handoff is a technology that allows a user to communicate without interruption of a call when the mobile station moves from one cell to another in the mobile communication system. There are two methods for the handoff, one of which is assigned a channel from a base station that is the target of the handoff during communication and communicates using a plurality of channels together with a channel received from a currently serving base station. It is a soft handoff to drop the dropped channel, and the second is a hard handoff during communication, which first disconnects the channel received from the currently served base station and attempts to access a neighboring base station.

Until now, the technology of the handoff has developed around a synchronous mobile communication system. However, with the advent of the asynchronous mobile communication system, the handoff technology between the asynchronous mobile communication system and the asynchronous mobile communication system is being researched. As the implementation of the asynchronous mobile communication system becomes possible, the handoff between the asynchronous mobile communication system and the synchronous mobile communication system is also studied. Off implementation is required.

In general, a mobile station communicating in a cell of a mobile communication system measures and reports information on neighboring cells to a base station when a pilot signal received by the mobile station has a predetermined value or a request from a base station of the mobile communication system. The reported information is used as information about the handoff generated when the mobile station moves to another cell during communication. The information is transmitted to the mobile station through a paging channel (in the case of a synchronous mobile system) or a broadcasting channel (in the case of an asynchronous mobile communication system).

In general, a hard handoff occurs when a mobile station moves from an asynchronous mobile communication system to a synchronous mobile communication system. When the hard handoff is performed, communication with the asynchronous mobile communication system is stopped while the mobile station is measuring information on neighboring cells.

In general, in order to interpret the system information in the conventional synchronous mobile communication system, the following process is required. The mobile station interprets the synchronization signal message contained in the synchronization signal frame transmitted in the synchronization channel of the synchronization mobile communication system. Here, the transmission bit per 80ms frame of the synchronization signal frame is 96 bits, and the length of the synchronization signal message including information that the mobile station can communicate with the synchronous mobile communication system is 221 bits. Therefore, the mobile station needs at least 240 ms (80 ms x 3) as the interpretation time of the message. The figures in the above description describe what is specified in the TIA / EIA-IS-2000.5 of the standard that defines the synchronous mobile communication system.

3 illustrates a process of measuring information on a synchronous mobile communication system around a asynchronous mobile communication system by a mobile station in communication in the asynchronous mobile communication system. Referring to FIG. 3, in step 301, the mobile station receives an information measuring instruction for a peripheral synchronous mobile communication system from an asynchronous mobile communication system base station. Then, in step 303, the mobile station starts searching for information on the synchronous mobile communication system around the asynchronous mobile communication system. In step 305, the mobile station detects the pilot signal of the synchronous mobile communication system. In step 307, the mobile station checks whether a pilot signal having a maximum amplitude is detected. At this time, when detecting the pilot signal having the maximum size, the mobile station proceeds to step 309. When the pilot signal having the maximum size is not detected, the mobile station returns to step 305 to perform the pilot signal detection operation of the synchronous mobile communication system again. . The mobile station that detects the pilot signal having the maximum size receives the synchronization frame transmitted in the forward synchronization channel of the synchronous mobile communication system in step 309. Here, the mobile station should receive at least three sync frames. When receiving a synchronous frame transmitted in the synchronous mobile communication system having a channel structure as shown in FIG. 2, the minimum reception time is 240ms, during which the mobile station stops communicating with the asynchronous mobile communication system. Therefore, a long time for performing the process illustrated in FIG. 3 may cause loss of communication data between the asynchronous mobile communication system and the mobile station.

The base station forward channel structure of a conventional synchronous mobile communication system is shown in FIG. Referring to FIG. 2, a forward pilot channel 203 for generating a pilot signal, a forward sync channel 204 for generating a synchronization signal, a forward dedicated control channel 202 for generating a control message for a dedicated channel, and a forward direction for generating a voice signal It consists of a dedicated basic channel 207 and a forward dedicated additional channel 208 for generating packet data. The detailed specification and operation of each channel is described in detail in the previously filed patent application P1998-11381 of the present applicant.

11 illustrates a handoff procedure when the mobile station moves from the asynchronous mobile communication system to the synchronous mobile communication system having the above structure. In the following description, the base station of the asynchronous mobile communication system is called an asynchronous base station A, and the base station of the synchronous mobile communication system is called a synchronous base station C.

Referring to FIG. 11, it is assumed that the mobile station B is handed off from the asynchronous base station to the synchronous base station 11003. 11 is a message transmitted and received between an asynchronous mobile communication system base station and a mobile station. The message 1101 of FIG. 11 is a message for transmitting information on neighbor cells updated by the base station receiving the message 1102 to the mobile station through a broadcast channel or a paging channel. After receiving the message of step 1102, the asynchronous mobile communication base station of FIG. 11 interprets the message of step 1102 to determine the handoff of mobile station B if there is another asynchronous base station to which mobile station B is to be handed off. If the mobile station B finds that it has not found the pilot signal of the other asynchronous base station to be handed off after interpreting the message of A, then the asynchronous base station sets parameters T, T ₀ , N for detecting the pilot signal of the synchronous base station, and then 1103. Sends a step message to the mobile station. The mobile station that has received the message of step 1103 of FIG. 11 measures the pilot signals of the synchronous base station and the asynchronous base station around the asynchronous base station. In FIG. 11, it is assumed that the mobile station has detected a pilot signal of the synchronization base station. After detecting the pilot signal of the synchronous base station, the mobile station analyzes the synchronous message transmitted through the forward synchronous channel of the synchronous base station, and then transmits a message to the asynchronous base station in step 1104. Upon receiving the message of step 1104, the asynchronous base station A receives the handoff command from the upper network to the synchronization base station C of the mobile station B, and transmits the message of step 1105. The message 1105 of FIG. 11 includes call channel information for a call at the synchronization base station C as a handoff direction message.

11 are messages transmitted and received between the mobile station 11002 and the synchronous mobile communication system base station 11003. 11 is a pilot signal continuously transmitted by the base station 11003 through a forward pilot channel. The step 1106 message is information transmitted through the forward pilot channel. The signal input to the forward pilot channel is always a logic signal 0 or 1 (both send 0 or send 1). The step 1106 message allows the terminal to estimate the channel and enable fast initial synchronization for a new multipath. The mobile station 11002 detects the PN_OFFSET value transmitted from the base station 11003 using the message 1106 to estimate the channel of the base station 11003. At this point, the mobile station 1102 0 does not know the exact PN_OFFSET of the base station, only the location of the PN_OFFSET with the maximum value. The mobile station 11002 detects the message of step 1106 and simultaneously receives the message of step 1107 to obtain information about the base station 11003. The step 1107 message is information contained in a sync frame transmitted through a forward sync channel. The message in step 1107 is a system identification number, a net ?? System information such as identification number, PN_OFFSET value, information about long code state after 320ms, paging channel data rate, etc. must be known. As an example of a synchronization channel through which the message of step 1107 is transmitted, a frame of a synchronization channel used in IS-95 has a length of 80 ms and consists of three subframes having an end call cycle length, and transmits 96 bits per frame. do. In the example of the synchronization channel, the system information is over 200 bits including the message length field and the CRC. In the example of the synchronization channel, the 80ms frame is transmitted with a length of 96 bits by inserting an extra bit even if the data length is not 96 bits. In the example of the synchronization channel, three 80 ms frames are required to include all the system information of the synchronization channel. Assuming that there is no transmission error of the step 1107 message in FIG. 11, and assuming that the mobile station 11002 receives the step 1107 message transmitted from the base station 11003, the mobile station 11002 finds that the base station transmitting the step 1107 message is the base station 11003. At least 240ms is required to find out the information. In FIG. 11, after receiving the message 1107, the mobile station 11002 transmits the information contained in the message 1107 to the base station as the message 1104. In FIG. 11, when the mobile station 11002 receives the handoff message from the base station 11001, the base station 11003 transmits the message to the mobile station in step 1108. The step 1108 message is null traffic or other data transmitted through the forward basic channel of the base station 11003, and the base station 11003 tests the stability of the channel with the mobile station 11002. In FIG. 11, the message 1109 received while the mobile station 11002 moves to the cell of the base station 11003 is a message transmitted through the forward basic channel. To be sent. 11, the mobile station 11002 receiving the message of step 1109 transmits a message of step 1110 through the reverse base channel. The step 1110 message is a reverse signal transmission (Preamble) to inform that the mobile station 11002 transmits normally. The mobile station 11002 having transmitted the message of step 1110 transmits the message of step 1111 to the base station.

The step 1111 message is a handoff completion message indicating that the mobile station 11002 has completed the handoff to the base station 11003. In FIG. 11, the base station 11003 receiving the message of step 1111 knows that the handoff of the mobile station 11002 is completed successfully.

As described above, in the forward channel structure of the conventional synchronous mobile communication system, in order to obtain system information of the synchronous mobile communication system of the mobile station, at least three sync frames transmitted on the forward sync channel of the synchronous mobile communication system must be received. do. In the case of the synchronous mobile communication system having the channel structure as shown in FIG. 2 as an example, the minimum reception time is 240ms, during which the mobile station stops communicating with the asynchronous mobile communication system. That is, when the time for performing the process shown in FIG. 3 is long, there is a problem that may cause loss of communication data between the asynchronous mobile communication system and the mobile station.

Accordingly, an object of the present invention relates to a base station communication apparatus and method of a synchronous mobile communication system using a forward monosynchronous channel for generating a PN_OFFSET signal.

Another object of the present invention is to provide a channel transmission apparatus and method for generating a PN_OFFSET signal in a synchronization system.

It is still another object of the present invention to provide a handoff procedure and apparatus that occur when a mobile station moves from an asynchronous mobile communication system to a synchronous mobile communication system using a forward monosynchronous channel generating a PN_OFFSET signal in a synchronous mobile communication system.

It is still another object of the present invention to provide an apparatus and method for reducing a time for a mobile station communicating in an asynchronous mobile communication system to collect information of a synchronous mobile communication system using a forward monosynchronous channel generating a PN_OFFSET signal in a synchronous mobile communication system. Is in.

A base station communication apparatus of a synchronous mobile communication system according to an embodiment of the present invention for achieving the above object is, the forward pilot channel generator for generating a pilot signal, the forward sync channel generator for generating a synchronization signal, and the PN_OFFSET signal of the base station It consists of a forward monosynchronous channel generator that generates, a forward dedicated control channel generator that generates control messages of the dedicated channel, a forward dedicated base channel generator that generates voice signals, and a forward dedicated additional channel generator that generates packet data. It is done.

In addition, the handoff process of the asynchronous mobile communication system according to an embodiment of the present invention for achieving the above object is the handoff from the asynchronous mobile communication system to the asynchronous mobile communication system, the handoff from the asynchronous mobile communication system to the synchronous mobile communication system Characterized in that can be performed.

In addition, in the asynchronous mobile communication system according to an embodiment of the present invention for achieving the above object, the mobile station in communication can detect the pilot signal of the base station of the asynchronous mobile communication system and the pilot signal of the base station of the synchronous mobile communication system for handoff. It is characterized by being.

1 is a diagram illustrating a base station structure of a synchronous mobile communication system having a single synchronization channel according to the present invention.

2 is a diagram illustrating a base station structure of a conventional synchronous mobile communication system.

3 is a diagram illustrating a process of measuring information on a synchronous mobile communication system by a mobile station in communication in an asynchronous mobile communication system;

FIG. 4 is a diagram showing a detailed configuration of a forward monosynchronous channel generator in FIG. 1; FIG.

FIG. 5 is a diagram showing the structure of single synchronous data input to the forward mono synchronous channel generator. FIG.

6 is a diagram illustrating repetitive transmission of a monosynchronous frame in one period of PN end call in the forward monosynchronous channel.

7 illustrates a handoff procedure of an asynchronous base station in accordance with the present invention.

8 illustrates a handoff procedure of a mobile station in accordance with the present invention.

9 illustrates a handoff procedure of a synchronous base station in accordance with the present invention.

10 is a diagram illustrating base station pilot signal detection parameters used in an asynchronous base station according to the present invention.

11 is a diagram illustrating messages transmitted and received when a mobile station according to the prior art moves from an asynchronous base station to a synchronous base station.

12 is a view showing messages transmitted and received when a mobile station moves from an asynchronous base station to a synchronous base station in the synchronous mobile communication system according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

DETAILED DESCRIPTION Hereinafter, a detailed description of preferred embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the same components in the drawings represent the same numerals wherever possible.

In the following description, specific details such as the length of the frames transmitted to each channel, the coding rate, and the number of data and symbols output from the blocks of the respective channels are shown to provide a more general understanding of the present invention. It will be apparent to those skilled in the art that the present invention may be readily practiced without these specific details and by modifications thereof.

The term short synchronization channel used in the following description refers to a forward channel of a synchronous mobile communication base station to which a message including PN_OFFSET information is transmitted.

In addition, the term "PN_OFFSET value" used in the embodiment of the present invention means a message transmitted through the monosynchronous channel, and the message transmitted through the monosynchronous channel is a pseudo noise code used by a synchronous mobile communication base station. Offset value of (Pseudo Noise Code).

1 is a diagram illustrating each channel configured in a terminal and a base station in a code division multile access (CDMA) communication system, which is one of synchronous mobile communication systems according to an embodiment of the present invention, and a configuration of each channel transceiver. An example is shown. In FIG. 1, each channel configuration is shown around the transmitter.

First, the channel configuration of the base station, the controller 101 performs the function (enable, disable) to control the operation of each channel generator of the base station, and processes the messages of the physical layer (physical layer) transmitted and received from the base station, It is responsible for communicating messages. The pilot channel generator 103, the synchronization channel generator 104, the single synchronization channel generator 105, the paging channel generator 106 is a device for generating common channel information commonly used by users in one cell or multiple cells, dedicated control channel generator 102, The basic channel generator 107 and the additional channel generator 108 are apparatuses for generating subscriber-only channel information allocated differently for each user.

The dedicated control channel generator 102 is responsible for processing and transmitting various control messages transmitted through a dedicated control channel (DCCH) of the forward link to the terminal. Messages transmitted through the dedicated control channel of the forward link are RLP (Radio Link Protocol) frames or various control messages (L3 signaling) used in the IS-95B, packet data such as allocating additional channels and releasing additional channels. It consists of a MAC (Medium Access Control) message, which is a control message related to service control. When the base channel is not used, the power control signal may be transmitted through a dedicated control channel. In this case, the control message may include the power control signal. In addition, in the forward dedicated control channel, a data rate to be used for the base station and the additional channel is negotiated, and when the orthogonal code is used for the additional channel, a command for changing the orthogonal code is also issued. In the dedicated control channel of the forward link, an unused orthogonal code among the unassigned orthogonal codes which are not assigned to the pilot channel generator 103, the synchronization channel generator 104, the monosynchronous channel generator 105, and the paging channel generator 106 is allocated and spread. The RLP frame provides a service capable of transmitting octet streams well. RLPs can be divided into transparent RLPs and non-transpatent RLPs. Transparent RLP does not retransmit erroneously transmitted frames, but informs the upper layer of the time and location of erroneously transmitted frames. Non-transparent RLPs provide error correction.

The pilot channel generator 103 is responsible for processing and transmitting the information transmitted through the pilot channel (pilot channel) of the forward link to the terminal. The pilot channel of the forward link always transmits a logic signal 0 or 1 (all 0's or all 1's). In this case, it is assumed that 0 logic signal is output to the pilot channel. The pilot channel signal allows the terminal to quickly acquiesce a new multipath and to estimate the channel. The pilot channel signal is spread by assigning one predetermined orthogonal code to a pilot channel.

The sync channel generator 104 is responsible for processing and transmitting information transmitted through a sync channel of a forward link to the terminal. Information transmitted through the synchronization channel is information for allowing terminals in a cell to match initial time synchronization and frame synchronization. A predetermined predetermined Walsh code is assigned to the sync channel of the forward link to spread the information of the sync channel.

The monosynchronous channel generator 105 is responsible for processing and transmitting information transmitted through a short sync channel of a forward link to the terminal. The information transmitted through the synchronous channel is a K-bit value having a size that allows the terminal communicating in the base station of the asynchronous mobile communication system to search for the information of the base station of the synchronous mobile communication system in a short time. The information is a PN_OFFSET value and zero padding bit of the synchronous mobile communication base station. The information is transmitted N ₂ times in the PN end call period so that the terminal communicating in the base station of the asynchronous mobile communication system can obtain the information quickly. K and N ₂ are shown in FIGS. 5 and 6, respectively. The information is received by a terminal communicating in an asynchronous mobile communication system in a PN end call period and transmitted to a base station of an asynchronous communication system. The information allows the base station of the asynchronous mobile communication system to update the information about the cells around the base station. The information is also used for handoff that occurs when a terminal communicating in an asynchronous mobile communication system moves to a base station of a synchronous mobile communication system. In addition to the information, information of a base station of a synchronous mobile communication system transmitted through a synchronous channel is transmitted from a base station of an asynchronous mobile communication system to a terminal using a paging channel or a broadcasting channel. The terminal receiving the information transmitted from the single-device channel moves in a situation in which the system information of the synchronous mobile communication base station moving when the mobile terminal moves to the synchronous mobile communication system base station can communicate without a separate synchronization process. The information transmitted in the monosynchronous channel is spread with the information of the monosynchronous channel by allocating one predetermined specific Walsh code that is identically used in all systems.

The paging channel generator 106 is responsible for processing and transmitting the information transmitted through the paging channel (paging channel) of the forward link to the terminal. The information transmitted on the paging channel is all the information needed before the communication channel is established. The paging channel of the forward link selects and spreads one of predetermined orthogonal codes.

The base channel generator 107 is responsible for processing and transmitting the information transmitted through the fundamental channel (fundamental channel) of the forward link to the terminal. Information transmitted on the base channel of the forward link is basically a voice signal. In addition, the information transmitted through the basic channel of the forward link may include various control messages (L3 signaling) and power control signals used in the IS-95B in addition to the voice signal. In addition, if necessary, a signal transmitted through the base channel of the forward link may include an RLP frame and a MAC message. The base channel uses a data rate of 9.6 kbps or 14.4 kbps, and depending on the situation, 4.8 kbps or 7.2 kbps having a rate of 1/2 of a given data rate may be used. 2.4 kbps or 3.6 kbps with a rate of 4 may be used, and a variable rate that may use 1.2 kbps or 1.8 kbps with a 1/8 rate is used. This modified data rate should be detectable at the receiving end. The base channel generator 107 of the forward link is a signal of the base channel by assigning an unused orthogonal code among the unsigned orthogonal codes not assigned to the pilot channel generator 103, the synchronization channel generator 104, the monosynchronous channel generator 105, and the paging channel generator 106. Output spread.

The additional channel generator 108 is responsible for processing and transmitting the information transmitted through the supplemental channel of the forward link to the terminal. Information transmitted through the additional channel of the forward link is an RLP frame, packet data, and the like. The additional channel generator 108 has a data rate of 9.6 kbps or more. The additional channel generator 108 has a scheduled data rate. As described above, the scheduled rate means that the base station and the terminal negotiate through the dedicated control channel to communicate at a data rate determined by the base station. The additional channel generator 108 of the forward link has an unused orthogonal code assigned to the pilot channel generator 103, the synchronization channel generator 104, the single synchronization channel generator 105, and the paging channel generator 106 to which the additional channel generator 108 is allocated. Spread the signal. In this case, the basic channel and the additional channel become a communication channel.

The adder 109 is the I-channel transmission signals of the forward link output from the dedicated control channel generator 102, the basic channel generator 107 and the additional channel generator 108, the pilot channel generator 103, the synchronization channel generator 104, the synchronous channel generator 105, and the paging channel. The transmission signal output from the generator 106 is added and output. The adder 110 adds and outputs Q-channel transmission signals output from the dedicated control channel generator 102, the basic channel generator 107, and the additional channel generator 108. The spreading modulator 119 performs a function of multiplying a transmission signal output from the adder 109 and the adder 110 by a spreading sequence and then up-converting the transmission signal to a frequency of the transmission signal. The receiver 121 receives the channel signals of the terminal received on the reverse link, converts the frequency into the base band, and multiplies the spread signal by the spreading sequence to despread it. In FIG. 1, the configuration of the channel receivers of the reverse link provided in the base station is omitted.

Second, referring to the configuration of the terminal, the controller 113 performs a function of controlling (enable, disable) the operation of each channel generator of the base station, processes the message of the physical layer (physical layer) transmitted and received from the terminal, the upper layer Responsible for communicating messages with

The dedicated control channel generator 114 is responsible for processing and transmitting various control messages transmitted through the dedicated control channel of the reverse link to the base station. The messages transmitted through the dedicated control channel of the reverse link include RLP (Radio Link Protocol) frames or various control messages (L3 signaling) used in the IS-95B, and a response to allocating additional channels and releasing additional channels. It consists of Medium Access Control (MAC) messages with contents. The dedicated control channel of the reverse link does not transmit the power control signal since the power control signal is inserted into the pilot channel and transmitted. It also negotiates the data rate to be used for the additional channel with the base station in the reverse dedicated control channel. The dedicated control channel generator 114 of the reverse link is pre-determined and spreads by orthogonal codes assigned to each channel to distinguish each channel and spreads to different user-assigned PN codes to distinguish users. In this case, the orthogonal codes are used to distinguish the channels. Therefore, different orthogonal codes predetermined for the dedicated control channel, pilot channel, access channel, basic channel, and additional channel are used. Use the same. For example, the orthogonal code used for the dedicated control channel means that all users use the same orthogonal code to distinguish the dedicated control channel.

In the dedicated control channel of the reverse link, the data rate is fixed at 9.6 kbps and transmitted. By fixing the data rate to 9.6kbps, the complexity of the receiver can be reduced by eliminating the performance due to data rate determination or the need for a data rate determination circuit. In addition, by having the same data rate as the basic data rate of the voice signal 9.6kbps has the advantage of maintaining the same service radius as the basic voice service.

The pilot channel generator 115 is responsible for processing and transmitting information transmitted through the pilot channel of the reverse link to the base station. The pilot channel signal of the reverse link, like the pilot channel signal of the forward link, enables fast initial synchronization for a new multipath and also enables channel estimation. While transmitting the power control signal at a certain point in time to transmit the reverse power control information.

The access channel generator 116 is responsible for processing and transmitting the information transmitted through the access channel (access channel) of the reverse link to the base station. The message of the access channel signal is composed of all information and control messages of the terminal required by the base station before the communication channel is established.

The base channel generator 117 is responsible for processing and transmitting information transmitted through the fundamental channel of the reverse link to the base station. Information transmitted on the base channel of the reverse link is basically a voice signal. In addition, the information transmitted through the base channel of the reverse link may include various control messages (L3 signaling) used in the IS-95B in addition to the voice signal. In addition, if necessary, a signal transmitted through the base channel of the reverse link may include an RLP frame and a MAC message. In the reverse link, the power control signal is transmitted through the pilot channel, so the power control signal is not transmitted through the base channel. The base channel uses a data rate of 9.6 kbps or 14.4 kbps, and depending on the situation, 4.8 kbps or 7.2 kbps having a rate of 1/2 of a given data rate may be used. 2.4 kbps or 3.6 kbps with a rate of 4 may be used, and a variable rate that may use 1.2 kbps or 1.8 kbps with a 1/8 rate is used. This modified data rate should be detectable at the receiving end. The base channel generator 117 of the reverse link is pre-determined and spread with an orthogonal code assigned to each channel to distinguish each channel and to distinguish a user with a PN code differently assigned for each user. In this case, the orthogonal codes are used to distinguish the channels. Therefore, different orthogonal codes predetermined for the pilot channel, the access channel, the basic channel, and the additional channel are used, and each orthogonal code used for each channel is the same for all users. . For example, the orthogonal code used for the basic channel means that all users use the same orthogonal code to distinguish the basic channel.

The additional channel generator 118 is responsible for processing and transmitting the information transmitted through the supplemental channel of the reverse link to the base station. Information transmitted through the additional channel of the reverse link is an RLP frame, packet data, and the like. The additional channel generator 118 has a data rate of 9.6 kbps or more. The additional channel generator 118 has a scheduled data rate. As described above, the scheduled rate means that the base station and the terminal negotiate through the dedicated control channel to communicate at a data rate determined by the base station. The additional channel generator 118 of the reverse link is pre-determined and spread with an orthogonal code assigned to each channel to distinguish each channel and to distinguish a user by a PN code that is differently assigned to each user. In this case, the basic channel and the additional channel become a communication channel.

The adder 119 adds and outputs transmission signals of the reverse link output from the dedicated control channel generator 114 and the pilot channel generator 115. The adder 120 adds and outputs transmission signals of the reverse link output from the access channel generator 116, the base channel generator 117, and the additional channel generator 118. The spreading modulator 121 performs a function of multiplying and spreading the transmission signals of the reverse link output from the adder 119 and the adder 120 by a spreading sequence, and then up-converting and transmitting the frequency of the transmission signal. The receiver 122 receives the channel signals of the base station received on the reverse link, converts frequencies into basebands, and multiplies them by a spreading sequence to despread. In FIG. 1, the configuration of the channel receivers of the forward link provided in the terminal is omitted.

As shown in FIG. 1, in a CDMA communication system according to an exemplary embodiment of the present invention, a base station includes a controller 101 for controlling all channels, a dedicated control channel generator 102 for processing signals transmitted through each channel, and a pilot channel generator 103. It consists of a synchronous channel generator 104, a single synchronous channel generator 105, a paging channel generator 106, a basic channel generator 107, and an additional channel generator 108. The terminal also includes a controller 113, a dedicated control channel generator 114, a pilot channel generator 115, an access channel generator 116, a basic channel generator 117, an additional channel generator 118. In addition, when the output form of each channel generator, the signals transmitted from the dedicated control channel generator 102, the basic channel generator 107, the additional channel generator 108 of the base station are I-channel (In-phase channel) component and Q channel (Quadrature-phase channel) Although two channel signals are generated, the pilot channel generator 103, the synchronization channel generator 104, the synchronous channel generator 105, and the paging channel generator 106 generate only one channel component. In this case, it is assumed that components generated by only one channel are output as I channel (Inphase channel) components only.

Each channel of the terminal outputs one channel component differently from the channels of the base station. Therefore, the outputs of the dedicated control channel generator 114 and the pilot channel generator 115 of the terminal are added to the I-channel (in-phase channel) input of the diffusion modulator 121, and the outputs of the remaining channels 116, 117, and 118 are added to the diffusion modulator 121. Q channel (Quadrature-phase channel) input. Since the access channel generator 116 generates an output before the communication channel is generated, the output of the pilot channel generator 115 is an I channel input and the output of the access channel generator 116 is a Q channel input when the access channel is used.

Detailed configuration and operation of all channel transmitters except for the single synchronous channel transmitter in FIG. 1 are described in detail in Korean Patent Application No. 98-11381 filed by the present applicant.

The present invention first describes a detailed configuration of the single synchronous channel transmitter, and then describes a handoff procedure from the asynchronous mobile communication system according to the embodiment of the present invention to the synchronous mobile communication system.

4 illustrates a detailed configuration of the single synchronization channel transmitter 105 according to an embodiment of the present invention.

Referring to FIG. 4, the encoder 401 encodes and outputs input single sync channel data. The encoder 401 may use a convolutional encoder or a turbo encoder. In FIG. 4, it is assumed that the encoder 401 uses a convolutional encoder having a code rate of 1/2 and a constraint length of 9. The iterator 402 repeatedly outputs the symbols output from the encoder 401 by N times. The interleaver 403 interleaves and outputs the symbols output from the iterator 402 to prevent the occurrence of a burst error. The interleaver may be a block interleaver, a turbo interleaver, or the like. The signal converter 404 converts the level of the short sync channel signal output from the interleaver 403. The multiplier 405 multiplies the orthogonal code by the synchronization channel signal output from the signal converter 404 and orthogonal modulates. The orthogonal code used in the multiplier 405 promises one of the Walsh codes in advance. The Walsh code used in the multiplier 405 should be only one specific Walsh code used in the synchronous mobile communication system. The length of the Walsh code used in the multiplier 405 uses the length specified in the synchronous mobile communication system. For example, Walsh codes of length 128 in IMT2000 SR1 and 256 in IMT2000 SR3 are used. The coder 401, repeater 402 and interleaver 403 used in FIG. 4 are not essential but optional, and the types of the coder 401, repeater 402 and interleaver 403 are also optional. In FIG. 4, the information input to the synchronous channel generator 105 may be in various forms. For example, there may be a method of transmitting only the PN_OFFSET value, a method of attaching a CRC to the PN_OFFSET value, and a method of encoding and transmitting PN_OFFSET by a separate encoding method.

5 is a diagram illustrating a frame structure of information input to the synchronous channel generator 105. FIG. Referring to FIG. 5, information 501 input to the synchronous channel generator 105 is a PN_OFFSET value of a base station of a synchronous mobile communication system. The PN_OFFSET value is represented by K bits. FIG. 5 shows an example in which the PN_OFFSET value and the Zero Pading Bit are K bits and CRC502 is attached during transmission. Currently, the PN_OFFSET = 9 is used in the synchronous mobile communication system. The data rate and the length of the CRC of the information input to FIG. 5 may be used differently depending on the Walsh code length, the number of repetitions, and the type of encoder.

FIG. 6 illustrates a structure in which a single synchronization channel frame is transmitted within one period of a PN code.

Referring to FIG. 6, a monosynchronous channel frame is transmitted N ₂ (N ₂ ≧ 1) times within one period of the PN end call. That is, several transmissions are possible instead of one PN_OFFSET value transmission in one period of PN code. Therefore, the terminal communicating with the base station of the asynchronous mobile communication system can acquire the information of the base station of the synchronous mobile communication system in a short time.

Equation 1 shows a method of determining the transmission frequency N ₂ of a single synchronization channel frame.

N_chip = {(K + CRC) × R × N ₁ × W ^l } × N ₂

If the variable used in Equation 1 is defined as follows.

N_chip = Number of chips in one cycle of PN code (32768 if SR1, 98304 if SR3)

K = data bit (PN_OFFSET value + length of zero padding bit)

CRC = CRC bit used in synchronous channel

R = code rate of encoder used in synchronous channel generator

N ₁ = number of symbol repetitions

W ^l = length of the Walsh code

N ₂ = Number of PN_OFFSET FRAME transmissions during one cycle of PN end call

For example, if 9 bits of PN_OFFSET and N_chip = 32768, R = 2, N ₁ = 2, W ^l = 128 are set in the current synchronous mobile communication system, 64 = (K + CRC) × N ₂ However, the bit rate of the monosynchronous channel is 2400 bps. To repeat a frame of a single synchronization channel twice, K + CRC must be 32 bits. If the CRC bit is 20, K includes 9 bits of PN_OFFSET value and 1 bit of zero fading.

As another example, if 9 bits of PN_OFFSET and N_chip = 32768, R = 2, N ₁ = 2, W ^l = 128 are currently used in the synchronous mobile communication system, 64 = (K + CRC) × N ₂ The bit rate of the monosynchronous channel is 2400 bps. In order to repeat a frame of a single synchronization channel four times, K + CRC must be 16 bits. If 4 bits are used for the CRC bit, K may be set to 12 bits including 9 bits of PN_OFFSET value and 3 bits of zero fading.

Hereinafter, a procedure for performing handoff from an asynchronous mobile communication system to a synchronous mobile communication system according to an exemplary embodiment of the present invention will be described. In the following description, the base station of the asynchronous mobile communication system is called asynchronous base station A, and the base station of the synchronous mobile communication system is called a synchronous base station C. In the following description of Figs. 7, 8 and 9, soft handoff is used between the asynchronous base station and the asynchronous base station. [0049] Further, C corresponding to the base station of the synchronous mobile communication system in the following description has the channel structure of Fig. 1 described above. Base station.

7 is a diagram illustrating a handoff procedure of an asynchronous mobile communication system base station capable of handoff to a synchronous mobile communication system.

Referring to FIG. 7, the asynchronous base station A receives pilot signal measurement results of neighboring asynchronous base stations from the mobile station B in step 701. The process of finding the asynchronous base station to be handed off by the mobile station B is to measure the pilot signal strengths of the asynchronous base stations around the asynchronous base station A without a separate report to the asynchronous base station A and find an asynchronous base station having a pilot signal of a predetermined value or more. Report to Asynchronous Station A. In step 702, the asynchronous base station A determines whether there is an asynchronous base station to which the mobile station B is to be handed off based on the measurement result received from the mobile station. If the mobile station B determines that there is an asynchronous base station to be handed off, the asynchronous base station A proceeds to step 703 and transmits a handoff direction necessary for handoff to the mobile station B. On the other hand, if the mobile station B determines that there is no asynchronous base station to be handed off, the asynchronous base station A proceeds to step 704 to determine the pilot signal detection parameters (T, T ₀ , N) of the mobile station B for the neighboring base station cells. Set it. Here, the pilot signal detection parameter for the synchronous base station cell is shown in FIG. As shown in FIG. 10, T ₀ is a time for detecting a pilot signal of a synchronous base station, T is a time interval for detecting a pilot signal of a synchronous base station, and N indicates how many times to find a pilot signal of a synchronous base station. Defined parameter. In step 705, the asynchronous base station A transmits the set parameter to the mobile station B, and transmits a message for measuring the pilot signal strength for the synchronous base stations and the asynchronous base station around the asynchronous base station A. Then, the mobile station B detects the pilot signal of the synchronization base station during the determined parameter T ₀ , and detects the pilot signal of the asynchronous base station and communicates with the asynchronous base station during (TT ₀ ) time. In step 706, the asynchronous base station A receives the pilot signal measurement result from the mobile station B. Here, the pilot signal measurement results transmitted from the mobile station B to the asynchronous base station A are classified into four types. That is, information for finding another asynchronous base station to be handed off, information for finding a synchronous base station to be handed off, information for finding another asynchronous base station to be handed off, and information for not finding a base station to be handed off. Among the information, the information found for the synchronization base station is transmitted together with the system information for the synchronization base station. Here, there are two types of system information of the synchronization base station, one is the PN_OFFSET value of the synchronization base station when the synchronization base station having a single synchronization channel as shown in FIG. 1 is found, and finds the synchronous mobile communication system as shown in FIG. When it is sent out, it is a synchronization message of the synchronization base station received through the synchronization channel. In step 707, the asynchronous station A having received the pilot signal measurement result from the mobile station B determines whether there is a target cell to be handed off. At this time, when it is determined that there is no target cell to be handed off, the asynchronous station B returns to step 701 to perform the following process again. On the other hand, when the target cell to be hand hop is found, the asynchronous base station A determines whether the target cell is an asynchronous base station or a synchronous base station in step 708. That is, since the asynchronous base station A measures both pilot signals of the asynchronous base station and the synchronous base station when setting parameters in step 704, it is necessary to determine whether the target cell found in step 708 is a synchronous base station or an asynchronous base station. In addition, if the synchronous base station and the asynchronous base station are found at the same time, which base station is to be hand hoped is a system setting parameter of the asynchronous base station A. Which base station should be given priority may be set in the system of the asynchronous base station A. In step 708, when the target cell to be hand hop is determined to be an asynchronous base station, the asynchronous base station A proceeds to step 709 and transmits information (Handoff Direction) necessary for handoff to the asynchronous base station to the mobile station A. On the other hand, when the cell to be hand-hop is determined to be a synchronous base station, the asynchronous base station A reports the synchronization signal of the synchronous base station pilot signal received from the mobile station B and the PN_OFFSET value or system information of the received synchronous base station to the higher network in step 706. . In step 710, the asynchronous base station A receives a request to handoff the mobile station B to the synchronization base station from the upper network. In this case, when handoff is performed to the synchronization system of FIG. 1, system information is received together. During step 710, the higher level network transmits information to the synchronous base station to be handed off that the mobile station B will be handed off. The reception target of the information may be a synchronization base station or a higher network of the synchronization base station. The asynchronous base station A, which has received a handoff request from the upper network, transmits information (Handoff Direction) necessary for handoff to the determined base station cell to the mobile station B.

As another embodiment, the asynchronous base station A may skip step 704 in the process of FIG. 7, and perform step 707 directly from the moment the mobile station B moves to the cell of the asynchronous base station A. FIG. The other embodiment has the advantage that the asynchronous base station A can shorten the time for handing off the mobile station B.

FIG. 8 is a diagram illustrating a procedure in which mobile station B communicating with an asynchronous base station B performs handoff. In FIG. 8, mobile station B is assumed to be a dual mode capable mobile station capable of communicating with an asynchronous base station and a mobile base station.

Referring to FIG. 8, the mobile station B measures the pilot signal received in step 801 and transmits the measurement to the asynchronous base station A. Here, the mobile station B transmits a message indicating that it has found an asynchronous base station to be handed off if it finds another asynchronous base station to be handed off, and transmits a message notifying that it has not been found. After receiving the response of the asynchronous base station B in step 801, the mobile station B determines whether the response is a pilot signal measurement request for the neighbor base stations of the asynchronous base station A in step 802. If the mobile station B receives the handoff message from the asynchronous base station A to the asynchronous base station target cell (the message transmitted in step 703 of FIG. 7), the mobile station B proceeds to step 803 to perform a handoff of the asynchronous base station to the target cell. Perform. In step 804, the mobile station B transmits a reverse transmission signal to the asynchronous base station which is the target cell. Thereafter, in step 805, a handoff complete message is transmitted to the asynchronous base station, which is the target cell, to inform that the handoff has been successfully performed.

On the other hand, if the message received in step 804 is the message transmitted in step 705 of FIG. 7, the mobile station B receives pilot signal detection parameters of the asynchronous base station and the synchronous base station in the vicinity of the asynchronous base station A in step 807. . In this case, the received parameters are values defined in FIG. 10. In setting the parameters received in step 806, it should be noted that if T ₀ is too long to find the pilot signal of the synchronization base station, a problem arises in the stability of communication with the asynchronous base station. If the interval of T is too long, the synchronization base station When N is large, difficulty in detecting a pilot signal occurs, and when N is large, the time for searching for a base station (synchronous base station or asynchronous base station) to be handed off is long, and the time for handoff of the mobile station B is missed, resulting in disconnection of a call.

In the following step 807, 813 steps, at the same time detects the pilot signal of the asynchronous base station for the mobile station B, detects the pilot signal strength of the synchronous base stations, and (TT ₀₎ time during T ₀ time to the time interval T for N times, The process of communicating with an asynchronous base station. In FIG. 8, mobile station B performs step 808 during the time of T ₀ and step 810 during (TT ₀ ). In step 808, a pilot signal of the synchronization base station is detected. In step 810, there are two methods for detecting a pilot signal of a synchronization base station. In order to detect the synchronization signal directly during the time of T ₀ and to ensure the stability of the call between the asynchronous system A and the mobile station B, set T ₀ to a small value and store the signal transmitted from the synchronization base station in the buffer of the mobile station B. This method detects the pilot signal of the synchronization base station from the signal stored in the buffer for (TT ₀ ) time. If the pilot signal of the synchronous base station is detected in step 808, the mobile station B performs step 809. The mobile station B interprets the system information from the synchronization channel or the single synchronization channel of the synchronization base station in step 809. If the method of directly detecting the synchronization signal during the T ₀ time is used in step 809, the mobile station B performs a channel with the synchronization base station for a time sufficient to obtain system information of the synchronization base station at the time when the pilot signal of the synchronization base station is detected. It shall be maintained and shall not return to the channel with the asynchronous base station. However, with the signals stored in the buffer in the 808 step if using the method for detecting the pilot signal of the sync base station in the next T ₀ of the T ₀ stores the pilot signal of the sync base station can obtain the system information of the synchronous base stations sufficiently Maintain channel with synchronization base station for time. In addition, in the case of a synchronous mobile communication system having no single synchronization channel, the mobile station B should receive the synchronization message transmitted to the synchronization channel of the synchronization base station for at least 240 ms in step 809. Therefore, in order to obtain information necessary for handoff in a mobile communication system that does not have a single synchronization channel as described above, it may not be possible to ensure stability in a call between the mobile station B and the asynchronous base station A. On the other hand, in the synchronous mobile communication system composed of the system of FIG. Receive the PN_OFFSET value of the synchronous base station transmitted in the synchronous channel within ms. In step 810, the mobile station B measures the asynchronous base station pilot signal strength around the base station A and maintains a call with the asynchronous base station A at (TT ₀ ) time. In step 811, it is determined whether the pilot signal strength of the asynchronous base station measured in step 810 is an appropriate value for handoff. At this time, when detecting the pilot strength suitable for handoff, the mobile station B proceeds to step 813, and otherwise proceeds to step 812. FIG. If the mobile station B does not detect the pilot signal of the synchronous base station or the asynchronous base station that can be handed off in steps 808 and 810, the mobile station B counts the number of executions in step 812 and exceeds N trials. To judge. If the number of times N has not been exceeded in step 812 and the pilot signal of the synchronous base station or the pilot signal of the asynchronous base station is not detected, the mobile station B returns to step 807 and repeats steps 808 and 810. On the other hand, if the number of times N is exceeded in step 812, the measurement result up to that point is transmitted to the asynchronous system A in step 813. If a signal is detected in step 808 within the N number of trials, and step 809 is performed, the mobile station B immediately performs step 813. If a signal is detected in step 810 within the N number of trials, and it is determined in step 811 that the base station has the appropriate pilot signal strength, the mobile station B immediately performs step 813. In step 814, the mobile station B determines whether a handoff message is received from the asynchronous base station A. If the handoff message is not received, the process returns to step 802 and repeats the following steps. If the handoff message is received, the process proceeds to step 815 and the handoff message received from the asynchronous base station A is transferred to the synchronization cell. It is determined whether the message is a handoff message or a handoff message to an asynchronous cell. At this time, if the message received in step 814 is a handoff message to the asynchronous cell, the mobile station B performs steps 819, 820, and 821. The steps 819, 820, and 821 are the same as the steps 803, 804, and 805 of FIG. If it is determined in step 815 that the handoff message is a handoff message to the synchronization cell, the mobile station B proceeds to step 816. The mobile station B performs handoff using the system information of the synchronous mobile communication base station included in the handoff message received in step 814 in step 816. That is, the mobile station B moves to the target cell in step 817, and then, after receiving the normal communication channel from the synchronous mobile communication system base station C as the forward basic channel, performs a reverse signal transmission to the synchronous base station C as the reverse basic channel. In step 818, a handoff complete message is transmitted to the synchronous mobile communication system base station C to the reverse base channel.

FIG. 9 shows a procedure for performing a handoff for a mobile station moving in an asynchronous mobile communication system using the system of FIG.

9, in step 901, the synchronous base station C transmits a pilot signal through a pilot channel and transmits a PN_OFFSET value of the base station C through a single synchronization channel. The PN_OFFSET value of the base station C transmitted through the monosynchronous channel may be transmitted as an example as shown in FIG. 5, or may be in various forms. The synchronous channel generator may be configured as shown in FIG. 4, and the encoder, interleaver, and repeater used in FIG. 4 are optional. The information on the single synchronization channel is 26.6. It is transmitted N ₂ times every ms. The synchronous base station C receives a handoff message from the higher network to base station C of the mobile station B in step 902. In step 902, the synchronization base station C receiving the handoff message from the mobile station B to the base station C transmits null traffic or other data to the mobile station B in the forward basic channel. Wherein step 903 is optional. From the moment when the mobile station B moves to the cell of the synchronous mobile communication base station C, the synchronous base station C normally transmits the call channel to the mobile station B using the forward basic channel in step 904. In step 905, the synchronization base station C receives a handoff completion message from the mobile station B.

12 is a diagram illustrating a handoff process performed when a mobile station moves from an asynchronous base station to a synchronous base station in a call channel control state when the synchronous base station has a single synchronous channel according to the present invention. In FIG. 12, it is assumed that mobile station 12002 is handed off from asynchronous base station 12001 to synchronous base station 12003. 12 through 1205 are messages transmitted and received between the asynchronous mobile communication system base station and the mobile station. Steps 1206 and 1213 are messages transmitted and received between the synchronous mobile communication system base station 12003 and the mobile station 12002. Step 1201 message of FIG. 12, step 1101 message of FIG. 11, step 1202 message of FIG. 12, step 1102 message of FIG. 11, step 1203 message of FIG. 12, step 1103 message of FIG. 11, step 1204 message of FIG. And step 1104 of FIG. 11, step 1205 of FIG. 12, step 1105 of FIG. 11, step 1206 of FIG. 12, step 1106 of FIG. 11, step 1208 of FIG. 12, and step 1108 of FIG. 11, The 1212 message of FIG. 12, the 1110 message of FIG. 11, the 1211 message of FIG. 12, and the 1111 message of FIG. 11 each perform the same function.

As described above, the asynchronous base station 12001 transmits information on other cells around the base station A to the mobile station through the broadcast channel in step 1201, and the mobile station 12002 transmits the pilot signal measurement result through the reverse dedicated channel in step 1202. Report to the asynchronous base station 12001. There are two types of messages of the mobile station 12002 reported to the asynchronous base station 12001 in step 1202. The mobile station 12002 may send information indicating that it has found another asynchronous base station that can be handed off, or transmit information that no other asynchronous base station was found. In FIG. 12, assuming that the mobile station 12002 transmits a message indicating that it has not detected a pilot signal of another asynchronous base station, the asynchronous base station 12001 sends a pilot signal to the mobile station 12002 about the synchronous base station and the asynchronous base station around the asynchronous base station 12001 in step 1203. A measurement is required, and the set parameters T, T ₀ , N are transmitted to the mobile station 12003 through the forward dedicated channel. In step 1206, the synchronization base station 12003 transmits a pilot signal through the forward pilot channel, and simultaneously transmits the PN_OFFSET value of the synchronization base station 12003 through the forward monosynchronous channel in step 1206. FIG. The mobile station 12002 receiving the message transmitted by the asynchronous base station 12001 in step 1203 measures the strength of the pilot signal for the other asynchronous base station and the synchronous base station around the asynchronous base station 12001 to obtain a pilot signal having the maximum size. In this embodiment, it is assumed that the signal of the synchronization base station 12003 is acquired. In this case, the mobile station 12002 obtains the PN_OFFSET value of the synchronization base station 12003 transmitted through the single synchronization channel of the synchronization base station 12003. In step 1204 of FIG. 12, the mobile station 12002 reports the PN_OFFSET value of the synchronous base station 12003 and the pilot signal measurement result to the asynchronous base station 12001. The message reported in step 1204 of FIG. 12 is transmitted to a higher network. Is sent to the asynchronous base station 12003 to the asynchronous base station 12003. At the same time, the system information about the synchronous base station 12003 is also transmitted from the upper network to the asynchronous base station 12001. In step 1205, the asynchronous base station 12001 transmits information necessary for handoff (including call channel information and system information for a call in the synchronous base station 12003) to the mobile station 12002 on a forward dedicated channel. On the other hand, the synchronization base station 12003 receives a handoff command from the upper network to the base station 12003 of the mobile station 12002. The synchronization base station 12003 transmits null traffic to the mobile base station 12002 on the forward basic channel simultaneously with receiving the handoff command. Thereafter, the mobile station 12002, which is out of the cell of the asynchronous base station 12001, moves to the cell of the synchronous base station 12003, and step 1209 is performed at the moment of moving to the cell of the synchronous base station 12003. In step 1209 of FIG. 12, the call between the asynchronous base station 12001 and the mobile station 12002 is transferred to the synchronous base station 12003, and the call channel is normally transmitted to the mobile station 12002. Thereafter, the mobile station 12002 transmits a reverse signal using a reverse base channel in step 1210, and transmits a handoff completion message to the synchronization base station 12003 in step 1211, indicating that the handoff is successfully completed.

12 and 11 differ in the manner in which the mobile station obtains system information of the synchronous mobile communication system.

The method of obtaining the system synchronization information of the base station 11003 by the mobile station 11002 shown in FIG. 11 uses a method of receiving the synchronization signal frame of the base station 11003 for at least 240 ms and interpreting the synchronization signal message contained in the synchronization signal frame. However, in FIG. 12, the mobile station 12002 obtains system synchronization information from the base station 12003 by taking only the PN_OFFSET value of the base station 12003 transmitted through the synchronous channel shown in FIG. 2, and transmitting the mobile station 12002 to the asynchronous mobile communication base station 12001. The base station 12001, which has received it, has received system synchronization information of the base station 12003 from its own network or from an upper network of the base station 12001, and the mobile station 12002 has received information about neighbor cells previously transmitted from the base station 12001. This method finds system synchronization information.

Since the synchronous channel message received by the mobile station 12002 in step 1207 of FIG. 12 is PN_OFFSET used by the synchronous mobile communication base station 12003, when the mobile station 12002 receives the synchronous channel message in step 1207, it is known from which synchronous base station. have. In this embodiment, it is assumed that the message received at 1207 by the mobile station 12002 is transmitted by the synchronous mobile communication base station 12003.

As illustrated in FIG. 5, the message 1209 may be transmitted in various types of applications if only the PN_OFFSET value of the synchronous mobile communication base station 12003 is included. As shown in FIG. 6, the message 1206 of FIG. 12 can be repeatedly transmitted several times within the period (26.6 ... ms) of the PN Short Code. Therefore, when the mobile station 12002 receives the PN_OFFSET value of the base station 12003, the required time is very small compared to the minimum time 240ms necessary for acquiring the mobile station system synchronization information in FIG.

As described above, in the present invention, in a mobile communication system in which an asynchronous system and a synchronization system coexist, the synchronization system base station can obtain information on neighbor cells within a short time while transmitting the PN_OFFSET value through a single synchronization channel. In addition, the mobile station communicating in the asynchronous communication system can easily perform the handoff operation to the synchronous communication system by using the PN_OFFSET value obtained through the synchronous channel. That is, since the mobile station communicating in the asynchronous mobile communication system can acquire the information on the neighboring cells of the asynchronous mobile communication system in a short time, it is possible to reduce the call disconnection time between the asynchronous mobile communication system and the mobile station. .

Claims (22)

A forward pilot channel generator for generating a pilot signal; A forward sync channel generator for generating a sync signal; A forward monosynchronous channel generator for generating a PN_OFFSET signal of a base station, A forward transmission control channel generator for generating a control message of a dedicated channel; A forward dedicated basic channel generator for generating a voice signal, A base station transmitter comprising a forward dedicated additional channel generator for generating packet data. The method of claim 1, wherein the synchronous channel generator, An encoder for encoding mono-synchronous channel data, A repeater for repeating symbols output from the encoder by a set number of times; An interleaver for interleaving the output of the iterator; A signal converter for converting the level of the monosynchronous channel signal output from the interleaver; And a multiplier for performing orthogonal modulation by multiplying an orthogonal code with a monosynchronous channel signal output from the signal converter. The method of claim 1, And the monosynchronous channel generator quadrature modulates and outputs data corresponding to the PN_OFFSET value. The method of claim 1, And said monosynchronous channel generator outputs a quadrature modulated data having CRC added to the PN_OFFSET value. The method according to claim 3 or 4, And the PN_OFFSET value is a data string represented by 9 bits. The method of claim 1, And a single synchronization channel frame generated by the single synchronization channel generator is transmitted at least once within a PN code period. The method of claim 6, The PN terminal code period is 26.666..ms characterized in that the base station transmitter. The method of claim 6, And a transmission frequency of the single synchronization channel frame is determined by Equation 2 below. N_chip = {(K + CRC) × R × N ₁ × W ^l } × N ₂ Here, N_chip = number of chips in one cycle of PN code (32768 for SR1 and 98304 for SR3) K = data bit (PN_OFFSET value + length of zero padding bit) CRC = CRC bit used in synchronous channel R = code rate of encoder used in synchronous channel generator N ₁ = number of symbol repetitions W ^l = length of the Walsh code N ₂ = Number of PN_OFFSET FRAME transmissions during one cycle of PN end call A method for performing handoff when a mobile station moves from an asynchronous base station to a synchronous base station having a single synchronization channel, When the mobile station detects a pilot signal of the synchronous base station at a maximum size, obtaining PN_OFFSET information transmitted through a forward monosynchronous channel from the synchronous base station, and transmitting the PN_OFFSET information to the asynchronous base station; And when the mobile station receives information necessary for handoff from the asynchronous base station, performing a handoff operation to the synchronization base station by using the information necessary for the handoff. The method of claim 9, And the information required for the handoff includes traffic channel information for the mobile station to communicate with the synchronization base station and system information of the synchronization base station. The method of claim 9, The PN_OFFSET information is a data string represented by 9 bits. The method of claim 9, The mono-synchronous channel frame is transmitted at least once in a PN code period. The method of claim 12, The PN terminal code period is characterized in that 26.666..ms. The method of claim 9, When the asynchronous station receives the PN_OFFSET information, the asynchronous station transmits the information to the upper network. Then, the base station system information corresponding to the PN_OFFSET received from the upper network and the traffic channel information for communication with the base station are transmitted to the mobile station as the handoff information. And further comprising transmitting. In the method of performing a handoff of the asynchronous base station when the mobile station moves from the asynchronous base station to the synchronous base station having the end call channel, Receiving pilot signal measurement results of neighboring asynchronous base stations to the mobile station; Notifying the mobile station to handoff to the asynchronous base station when it is determined that there is an asynchronous base station to handoff from the measurement result; Determining and transmitting a pilot signal detection parameter for a synchronous base station cell when determining that there is no asynchronous base station to hand off; Determining whether a target cell to be handed off is a synchronous base station upon receiving the pilot signal measurement result from the mobile station; And receiving system information of the synchronous base station from the synchronous base station temporary upper network and transmitting the information to the mobile station together with information necessary for handoff. The method of claim 15, And when notifying that the target cell to be handed off is an asynchronous base station, informing the mobile station to handoff to the asynchronous base station. The method according to claim 15 or 16, The pilot signal detection parameter includes a synchronization base station pilot signal detection period (T), a synchronization base station pilot signal detection time (T ₀ ), and a synchronization base station pilot signal detection frequency (N). In the method of performing a handoff of the mobile station when the mobile station moves from the asynchronous base station to the synchronous base station having a single synchronization channel Receive pilot signal measurement parameters of neighboring base stations at handoff, detect pilot signal of synchronous base station during the first search section according to the received measurement parameter, detect pilot signal of neighbor asynchronous base station during second search section, and , Repeating this the set number of times, Receiving a PN_OFFSET value through a synchronous channel of the synchronous base station in the presence of a synchronous base station in which a pilot signal is detected at a set level or higher in the first search section, and transmitting the PN_OFFSET value to the asynchronous base station with a measurement result; Transmitting a measurement result to the asynchronous base station in the presence of an asynchronous base station in which a pilot signal is detected to be above a set level in the second search section; Determining whether a target cell is a synchronous base station or an asynchronous base station when receiving a handoff message from the asynchronous base station; And the target cell performs a handoff operation to the synchronous base station at the time of the synchronous base station, and the target cell performs a handoff operation to the asynchronous base station at the time of the asynchronous base station. The method of claim 18, The first search section has a time period relatively smaller than the second search section. The method of claim 19, The mobile station detects the pilot signal in the second search section and simultaneously communicates with the asynchronous base station. The method of claim 19, And the mobile station temporarily stores a signal of a synchronization base station received during the first search period, and detects the strength of a pilot signal with the stored signal in the second search period. When the mobile station moves from the asynchronous base station to a synchronous base station having a single synchronization channel, Transmitting a pilot signal and transmitting its own PN_OFFSET information through the single synchronization channel; Transmitting traffic data to a forward basic channel allocated to the mobile station when receiving information indicating that the mobile station is handed off to its cell from an upper network; And completing a handoff operation upon receiving a handoff complete message from the mobile station.