KR20000073866A - Apparatus and method for processing handoff of supplemental channel in a mobile telecommunicaion system - Google Patents

Abstract

PURPOSE: A method and a device for processing handoff of a supplemental channel in a mobile communication system, are provided to add specification/assignment information for the supplemental channel to a universal handoff direction message(UHDM) in a process of handoff so that the number of messages transceived between a base station and a terminal can be reduced, and to perform scheduling for burst information transmitted to the supplemental channel so that an appropriate supplemental channel can be set up. CONSTITUTION: If a pilot exceeding a reference value is detected, a resource controller of a terminal informs the pilot to a control message processor of a terminal. If a new pilot is added by being compared with a pilot of an existing active set, the control message processor transmits a pilot strength measurement message(PSMM). A control message processor of a base station receiving the PSMM recognizes the added pilot. The control message processor of the base station delivers a handoff request message to a resource controller of a destination base station. The control message processor of the base station transmits a universal handoff direction message(UHDM) to the terminal. The control message processor of the terminal interprets code information on a forward channel, and delivers a traffic channel assignment message to the resource controller of the terminal, to prepare interpretation of signals transmitted from forward channels in an active set. The control message processor of the terminal transmits a handoff completion message to the base station, to complete a handoff process. In a process performing handoff for a supplemental channel, a central resource controller checks resource availability according to cells in a cell resource controller. The central resource controller stores a checked result in a resource shape database, to confirm information on available resource of each cell. The central resource controller performs scheduling to properly transmits present burst data in a handoff situation based on the resource availability. And the central resource controller performs specification and assignment of a supplementary channel to transmit the scheduled burst data.

Description

Apparatus and method for handoff processing of additional channel in mobile communication system {APPARATUS AND METHOD FOR PROCESSING HANDOFF OF SUPPLEMENTAL CHANNEL IN A MOBILE TELECOMMUNICAION SYSTEM}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a code division multiple access (CDMA) mobile communication system, and more particularly, to an apparatus and method for processing handoff of an additional channel.

In general, the CDMA mobile communication system has provided voice-oriented services, but gradually developed to the IMT-2000 standard capable of high-speed data transmission as well as voice. The mobile communication system of the IMT-2000 standard enables high quality voice, moving picture, internet search, and the like. The data communication performed in the mobile communication system is characterized in that the generation of data is concentrated at the moment, and the idle state frequently occurs for a long time in which a state in which data is not transmitted is frequently generated.

Therefore, the next generation mobile communication system considers a method of allocating a dedicated channel only at the time of data transmission in a data communication service. That is, in the next generation mobile communication system, a dedicated channel is connected only while actual data is transmitted in consideration of limited radio resources, base station capacity, and power consumption of the mobile terminal. Release the dedicated channel. As described above, the next generation mobile communication system is focusing on enhancing the efficiency of radio resource utilization by performing communication through a common channel while a dedicated channel is released.

The dedicated channel includes a basic channel, a dedicated control channel, a supplemental channel, and the like. Basically, the voice call does not require a large amount of data transmission, so there is no need to allocate a channel with a high transmission rate. So we have used a basic channel with a transmission rate of 9.6kbps or 14.4kbps.

Meanwhile, in the next generation mobile communication system, data is transmitted using an additional channel capable of high speed transmission for packet data transmission. The allocation of the additional channel is performed by a unique additional channel allocation procedure when it is necessary to transmit the data beyond the transmission rate of the basic channel or the dedicated control channel. This additional channel first allocates a basic channel or a dedicated control channel, thereby enabling high-speed data transmission.

1A and 1B are diagrams illustrating a structure of an Extended Supplemental Channel Assignment Message (hereinafter, referred to as ESCAM) used in additional channel allocation in a next generation mobile communication system of the IS-2000 standard.

1A and 1B, the ESCAM may be largely divided into four parts. That is, the ESCAM firstly relates to a handoff direction message, and has a state transition information, and secondly, information for specifying a code channel list of an additional channel. The third part is assigned to the forward / reverse additional channel and duration to be used for transmission of the burst among the specified code group, and finally the forward outer loop power control. It can be divided into parts that transmit additional channel related information used when performing (Forward Link Outer Loop Power Control). Here, it will be appreciated that the part of the present invention is concerned with the specification and assignment of additional channels, which are the second and third parts.

The ESCAM having the structure shown in FIGS. 1A and 1B is a message for designating and configuring an additional channel. The message fields used for designating and configuring the forward and reverse side channels are as follows.

In the case of designating and configuring the forward additional channels, first, a plurality of additional channel candidate groups are specified so that channel allocation is possible for various predictable transmission rates. The FOR_SCH_ID field of FIG. 1A is used to distinguish channel elements when allocating several physically different channel elements for additional channels. The NUM_REC field of FIG. 1A indicates whether a Walsh code that logically supports several different data rates for different FOR_SCH_IDs is designated. The SCCL_INDEX field of FIG. 1A is used to indicate codes indicating various data rates as simple separators. The FOR_SCH_RATE field of FIG. 1A indicates a transmission rate supported by an orthogonal code designated by a corresponding SCCL_INDEX. The NUM_SUP_SHO field of FIG. 1A indicates the number of pilots currently constituting an active set. The PILOT_PN field of FIG. 1A represents a PN (Pseudo Noise) value of a pilot channel constituting an active set. The fields ADD_PILOT_REC_INCL, ACTIVE_PILOT_REC_TYPE, RECORD_LENGTH, and Type-specific fields of FIG. Finally, the FOR_SCH_CC_INDEX field of FIG. 1A directly represents Walsh orthogonal code values corresponding to SCCL_INDEX and PILOT_PN.

After using the various fields as described above, a candidate group for various transmission rates is designated, and then an arbitrary value suitable for the corresponding burst transmission is set among the candidate groups by using assignment information. When the allocation information is given down, the value of the FOR_ASSIGN_INCLUDED field of FIG. 1A is set to '1'. In this case, the FOR_SCH_ID field of FIG. 1A added in this case is used to indicate physically divided channels as described above. The FOR_DURATION field of FIG. 1A indicates how long the additional channel is to be used to perform the corresponding burst transmission. The FOR_START_TIME field of FIG. 1A indicates a time at which the burst transmission starts. SCCL_INDEX of FIG. 1A is a delimiter for designating a code channel with a value used in the designation information.

In the case of designating and setting uplink additional channels, since each terminal needs to be distinguished instead of having a Walsh orthogonal code, it does not have specific information. If the REV_ASSIGN_INCLUDED field of FIG. 1A is set to '1', the allocation information of the uplink additional channel includes the following fields. The REV_SCH_ID field of FIG. 1A is a field indicating a division of a physical channel like the forward additional channel. The REV_DURATION field of FIG. 1A indicates a period during which an additional channel should be used for a corresponding reverse burst transmission. The REV_START_TIME field of FIG. 1A indicates a time point at which reverse burst transmission is started. The RATE field of FIG. 1A indicates an appropriate transmission rate to be used in the corresponding burst transmission.

2A and 2B are diagrams illustrating a structure of a universal handoff direction message (hereinafter referred to as UHDM) to be used during handoff processing in an IS-2000 standard mobile communication system. Here, only the message fields related to handoff of additional channels related to the present invention will be described.

In the handoff process of the additional channel, the additional channel information is separately processed for each active set. The SCH_INC field of FIG. 2B indicates whether additional channel related information is added in the UHDM. The NUM_SCH field of FIG. 2B is a field indicating the number of additional channels physically divided. In general, the reason for physically distinguishing additional channels is to assign different physical channels having different characteristics in consideration of the fact that traffic characteristics may be different for each service. The SCCL_INDEX field of FIG. 2B is for representing a plurality of code channels with a simple separator. The FOR_SCH_RATE field of FIG. 2B indicates a data rate required for forward burst transmission on an additional channel. The CODE_CHAN_SCH field of FIG. 2B indicates a Walsh orthogonal value of the additional channel. The QOF_MASK_ID_SCH field of FIG. 2B indicates a value of a quasi orthogonal function mask.

Meanwhile, in the mobile communication system, the handoff process may be completed only when the UHDM and ESCAM having the above structure are transferred and used together with the base station and the terminal. When the additional channel is allocated using only the message field of the UHDM, since information such as duration is not included, it is necessary to inform the terminal by transmitting the above information through another message. Also, if only the message field of the UHDM is used, the candidate group designation process cannot be performed. Therefore, when the transmission rate of the additional channel is changed after the handoff is completed, another message needs to be transmitted to allocate the additional channel. A message that meets this need is an ESCAM having the structure shown in Figures 1A and 1B. That is, UHDM is used for handoff of an additional channel. In addition to this UHDM, ESCAM must also be used to perform normal additional channel handoff.

However, when the handoff of the additional channel is processed by using both the UHDM and the ESCAM, there is a problem in that the number of messages transmitted and received between the base station and the terminal is large, and the burst information transmitted to the additional channel after the handoff processing is completed There is a complexity of the procedure of rescheduling.

Accordingly, an object of the present invention is to provide an apparatus and method for optimizing handoff processing of an additional channel in a mobile communication system.

Another object of the present invention is to provide an apparatus and method for reducing the number of messages exchanged between a base station and a terminal during handoff processing of an additional channel in a mobile communication system.

Another object of the present invention is to provide an apparatus and method for simultaneously processing burst information transmitted on an additional channel during handoff processing of the additional channel in a mobile communication system.

According to the present invention for achieving these objects, a universal handoff direction message (UHDM) includes information for designating an additional channel candidate group for a plurality of predictable transmission rates, and information for allocating an appropriate value among the candidate groups for the burst transmission. An apparatus and method for processing handoff of an additional channel using

1A and 1B illustrate the structure of a general Extended Side Channel Assignment Message (ESCAM).

2A and 2B illustrate the structure of a general universal handoff indication message (UHDM).

3A and 2B illustrate the structure of a universal handoff indication message (UHDM) in accordance with the present invention.

4 shows a procedure for handoff processing in accordance with the present invention.

5 is a flowchart of a base station for handoff processing of an additional channel according to the present invention;

6 is a flowchart of a terminal for handoff processing of an additional channel according to the present invention;

7 is a diagram illustrating a configuration of a base station for handoff processing of an additional channel according to the present invention.

8 is a flowchart of a handoff process of an additional channel performed by a base station shown in FIG.

DETAILED DESCRIPTION A detailed description of preferred embodiments of the present invention will now be described with reference to the accompanying drawings. In the following, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even if displayed on different drawings.

First, in the present invention, by adding a message field and modifying a procedure, the base station and the mobile station can perform a handoff of the additional channel by UHDM alone without using UHDM and ESCAM simultaneously. It's important to note that you are optimizing for sending and receiving messages. In addition, it is to be understood that the present invention is to process the burst information transmitted to the additional channel during the handoff processing of the additional channel.

3A and 3B illustrate a structure of the UHDM proposed by the present invention, and the UHDM further includes information for specifying and assigning additional channels, which are functions of the existing ESCAM. That is, the present invention designates and allocates additional channels using UHDM, and processes handoffs including the assignment and assignment of such additional channels. Message fields added in the present invention are underlined. If the UHDM is configured as described above, the FOR_START_TIME field and the REV_START_TIME field of FIG. 1A may be omitted from the existing ESCAM structure. This is because, instead of these, the present invention can use the action time of the UHDM (Universal Handoff Direction Message).

First, in the present invention, a process of designating a forward additional channel using UHDM having a structure as shown in FIGS. 3A and 3B is performed. To this end, a NUM_REC field as shown in FIG. 3B is added to a field repeated in each active set, and the designated information of additional channels is repeated by NUM_REC number (0 to 4). By using the repeated additional channel designation information, additional channel candidate groups can be designated for a plurality of predictable data rates. The FOR_SCH_ID field of FIG. 3B is for identifying channel elements when allocating a plurality of physically different channel elements for additional channels. The SCCL_INDEX field of FIG. 3B is used to indicate codes indicating various data rates with simple separators. The FOR_SCH_RATE field of FIG. 3B is for indicating a transmission rate supported by an orthogonal code designated by the corresponding SCCL_INDEX. The NUM_SUP_SHO field of FIG. 3B is used to indicate the number of pilots currently constituting the active set. The CODE_CHAN_SCH field of FIG. 3B is used to directly indicate Walsh orthogonal code values corresponding to SCCL_INDEX and PILOT_PN. Finally, the QOF_MASK_ID field of FIG. 3B is added.

In addition, in the present invention, an assignment process for delivering specific information of an additional channel to be used currently is performed by using the UHDM having the structure shown in FIGS. 3A and 3B.

As described above, when additional channel candidate groups for various transmission rates are set, an arbitrary value suitable for the burst transmission is set among the candidate groups. The FOR_SCH_ID field of FIG. 3B is used to indicate physically divided channels. The FOR_DURATION field of FIG. 3B indicates how long the additional channel is to be used to perform the corresponding burst transmission. The FOR_START_TIME field indicates the time at which the burst transmission starts. SCCL_INDEX of FIG. 3B is a delimiter for designating a code channel with a value used in the designation information.

In the case of the reverse side additional channel, since each terminal only needs to be distinguished without a Walsh orthogonal code, the reverse side additional channel does not have specific information. The REV_SCH_ID field of FIG. 3B is a field indicating the division of a physical channel like the forward additional channel. The REV_DURATION field of FIG. 3B indicates a period in which an additional channel should be used for the corresponding reverse burst transmission. The REV_START_TIME field indicates a time point at which reverse burst transmission is started. The RATE field of FIG. 3B indicates an appropriate transmission rate to be used in the corresponding burst transmission.

As described above, in the present invention, the UHDM further includes information for designating and assigning an additional channel, which is a function of the existing ESCAM. A procedure for processing handoff of an additional channel using such UHDM is shown in FIG. 4. In FIG. 4, base station 1 (BS) is a base station serving data through an additional channel with a current mobile station (MS), and base station 2 is handed off to provide data through a terminal and an additional channel. Target base station to be made.

In FIG. 4, the control message processor (interpreter / generator) SIG 100 performs a process of processing a control message related to call setup of a base station. Resource controller (RC) 110,210 is a part that manages and controls the resources of the base station, such as the orthogonal code of the base station or a channel element (CE). The channel elements CE 120 and 220 are physical channel processing parts that actually transmit a message or data to a base station or a terminal. The control message processor 320 is a part of the terminal for processing a control message related to call setup. The resource controller 310 manages and controls various logical and physical resources of the terminal. The channel element 300 is a physical channel processing part that is responsible for transmitting an actual signal from a terminal.

In operation 410 of FIG. 4, if a pilot having a strength exceeding a preset reference value T_ADD is detected, the resource controller 310 of the terminal notifies the fact to the control message processor 320 of the terminal. The control message processor 320 transmits a pilot strength measurement message (PSMM) in step 220 when a new pilot is added as compared with a pilot of an existing active set. The control message processor 100 of the base station 1 receiving the PSMM recognizes the newly added pilot.

Next, the control message processor 100 sends a handoff request message (HandoffReq.) To the resource controller 210 of the destination base station 2 added in step 431. The resource controller 210 transmits a traffic channel allocation message (TC_assign_msg) to the channel element 220 when various physical resources are available after receiving the handoff request message (Handoff Req.), And in step 433, the control message processor. Send a handoff assignment message (HandoffAssign) to 100. Steps 431 to 433 are steps for allocating a new traffic channel to the added base station 2.

Next, in step 440, the control message processor 100 of the base station 1 transmits the UHDM to the terminal. In this case, the main content of the UHDM is to transmit code information about a newly added physical channel. The control message processor 320 of the terminal interprets the code information of the forward channel, and transmits a traffic channel allocation message (Tc_assign_msg) to the resource controller 310 of the terminal in step 350 so that the signal transmitted from various forward channels in the active set can be interpreted. Prepare. In step 360, the control message processor 320 completes the handoff process by transmitting a handoff completion message to the base station1.

In order to allocate the additional channel to the added pilot when the processes 431 and 432 are applied to the additional channel, the resource controller 210 of the base station 2 checks the transmission rate of the corresponding additional channel or the state of the remaining resources to determine the additional channel. It finds whether it is allocated and the appropriate transmission rate when assigning.

5 is a diagram illustrating a flow performed in a base station for handoff processing of an additional channel according to the present invention.

When the PSMM transmitted by the terminal in step 501 is received by the control message processor 100 of the base station 1, the control message processor 100 checks whether the UHDM is available in the base station 2 corresponding to the newly added pilot PN. If it is determined that the UHDM is not available in the base station 2, in step 512 generates a General Handoff Direction Message (GHDM) for the second generation mobile communication system. If the base station 2 determines that the UHDM can be used, the control message processor 100 checks whether the additional channel (SCH) is in use in step 503. If the additional channel is not set, a process of generating a message field to be described later for the additional channel is omitted.

If the additional channel is set, the resource manager 210 of the base station 2 added in step 504 informs the control message processor 100 of the currently available available resources. In step 505, it is checked whether the resource identified in step 504 can transmit the data burst currently being transmitted. If transmission is possible in the above process, the control message processor 100 performs scheduling for data for the burst of data being transmitted, finds out the appropriate transmission rate and transmission time of the additional channel in the current cell situation, and processes the appropriate transmission environment setting. . If the additional channel can be set through the above process, the control message processor 100 sets the additional channel designation information possible in step 506, sets the allocation information of the additional channel to be used for the corresponding burst transmission in step 507, and as a result, It is transmitted to the base station resource controller 110, 210 and receives a confirmation process for the setting result.

In step 508, a UHDM message including additional channel related fields is generated based on the above process. If it is determined in step 504 and 505 that the resource state of the current cell is not possible to allocate an additional channel, step 506 and step 507 are omitted and the step 508 is performed immediately. The generated UHDM is transmitted from the existing base station 1 and the added base station 2 to the terminal. The terminal receiving the UHDM sets the channel information and then transmits the HCM. In step 510, the base station receives the HCM from the terminal, thereby completing all handoff processes.

FIG. 6 is a diagram illustrating a handoff processing flow of an additional channel performed in a terminal in response to the handoff processing flow of the additional channel as shown in FIG. 5.

In step 601, the terminal examines information about a pilot whose signal strength exceeds a reference value T_ADD during the pilot search process. At this time, if a new pilot is confirmed, the verification result is reported to the control message processor 320 of the terminal. The control message processor 320 generates a PSMM based on the reported pilot and transmits the PSMM to the control message processor 100 of the base station 1.

In step 602, the terminal receives the UHDM transmitted by the base station 1 and the base station 2 based on the PSMM by performing steps 508 and 509 of FIG. In step 603, the control message processor 320 of the terminal interprets the UHDM. In this case, if it is determined that the additional channel information is included, the control message processor 320 interprets a specification field of the forward additional channel in step 604 and stores the specified additional channel information. The result analyzed in step 604, that is, the information of the additional channel is notified to the resource controller 310. In step 605, the control message processor 320 interprets an assignment field of the forward / reverse additional channel and notifies the resource controller 310 of the analysis result when the forward or reverse additional channel allocation field is included. The resource controller 310 then instructs the channel element 300 to demodulate a corresponding additional channel. When the interpretation of the field of the UHDM including the additional channel related operation and the preparation process of the terminal is completed, the terminal transmits the HCM message to the base station and completes the handoff operation in step 606.

FIG. 7 shows the control message processor 100 and the resource controller 281 of the base station of the module of FIG. 4 in more detail by function.

The base station control message processor 100 of FIG. 4 may be classified into a message processor (message interpreter / generator) 730, a resource data base 710, and a central resource controller 720 by function. The remaining Cell Resource Control 740 is the same as the reference numeral 210 of FIG. 4, and the channel element 750 is the same as the reference numeral 220 of FIG. 4.

FIG. 8 is a diagram illustrating a processing flow between functional modules performed in a handoff process of an additional channel based on the functional module segmented in FIG. 7. This has been described above with reference to steps 430 and 431 of FIG. 4.

When the process of handoff of the additional channel is started in step 801, the central resource controller 720 checks the resource availability of each cell by the cell resource controller 740. In step 803, the central resource controller 720 stores the survey result in the resource shape database 710 to check information on available resources for each cell. In step 804, the central resource controller 720 performs scheduling to properly transmit current burst data in a situation including handoff based on resource availability of each cell. At 805, the central resource controller 720 performs assignment and assignment of additional channels for transmission of the scheduled burst data. In step 806, the central resource controller 720 notifies the cell resource controller 740 of the information on the allocated resource to prepare for modulation / demodulation of the additional channel.

As described above, the present invention reduces the number of messages exchanged between the base station and the terminal by adding the additional channel designation and allocation information to the UHDM during the handoff process, and reschedules the burst information transmitted to the additional channel again in the handoff situation. By (Scheduing), it is possible to set the appropriate additional channel.

Claims (3)

Handoff of an additional channel using a Universal Handoff Direction Message (UHDM) including information designating additional channel candidate groups for a plurality of predictable rates and information for setting an arbitrary value suitable for the corresponding burst transmission among the candidate groups. Handoff processing apparatus of the additional channel in the mobile communication system for processing. Transmitting, by the terminal, a pilot strength measurement message (PSMM) to the base station when the pilot exceeds the reference value; Transmitting, by the base station, a universal handoff direction message (UHDM) to the terminal based on the PSMM; Designating, by the terminal, a plurality of additional channel candidate groups according to information included in the UHDM; And performing a handoff to a new base station by setting an additional channel suitable for the burst transmission among the candidate groups, and performing handoff of the additional channel in the mobile communication system. Transmitting, by the terminal, a pilot strength measurement message (PSMM) to the first base station of the active set when the pilot exceeds the reference value; Allocating a traffic channel of the second base station identified by the pilot; Transmitting, by the first base station and the second base station, a universal handoff direction message (UHDM) to the terminal based on the PSMM; Setting, by the terminal, corresponding channel information according to the UHDM, and transmitting a handoff completion message (HDM) to the first base station and the second base station. Treatment method.