KR100630179B1 - Method for assigning supplemental channel of reverse link in cdma communication system - Google Patents

Abstract

This, when the channel assignment request from a terminal, using SCAM compared the process of obtaining the amount R _Available the available channels and, the available channel capacity R _Available the spare channel capacity, the method of allocating the mobile communication base station a reverse supplemental channel of the system comparing the available channel capacity R _available and the terminal rate of the supplemental channel request R _mobile when to the determining whether to accept and accepting the assignment of additional channels and channel occupation that is currently used as R _current and channel capacity The process of comparing the reference value R _Threshold , and if R _Available is greater than R _mobile and R _Current is greater than R _Threshold , allocates an additional channel of the requested transmission rate, and if any one of the two comparison values is smaller, the transmission rate is lower than the required transmission rate. Allocating additional channels of the UE and generating an additional channel assignment message including information on the allocated additional channels; It comprises a step of transmitting to the terminal.

Side Channel Assignment, Reverse Channel Assignment, SCRM, ESCAM

Description

METHODS FOR ASSIGNING SUPPLEMENTAL CHANNEL OF REVERSE LINK IN CDMA COMMUNICATION SYSTEM}             

1 is a diagram illustrating a process of allocating an additional channel of a reverse link in a conventional code division multiple access communication system.

2 is a diagram illustrating a process of allocating an additional channel of a reverse link in a code division multiple access communication system according to an embodiment of the present invention.

3 illustrates a structure for allocating additional channels of a reverse link according to an embodiment of the present invention.

4 is a flowchart illustrating an operation of allocating a reverse additional channel according to an embodiment of the present invention in a code division multiple access communication system.

The present invention relates to a channel allocation method of a code division multiple access communication system, and more particularly, to a method of allocating a dedicated additional channel of a reverse link.                         

Code Division Multiple Access (hereinafter referred to as CDMA) communication system has common channels and dedicated channels, and the allocation of these channels has already been determined. References [1] and [2] are disclosed for a specification related to reverse SCH channel allocation of a cdma2000 system, which is one of the next generation CDMA communication methods. (Ref. [1]: TIA / EIA / IS-2000.5-A, Upper layer (Layer 3) signaling standard for cdma2000 spread spectrum systems, Post-ballot version, 21 March 2000. Ref. [2]: TIA / EIA / IS-707-A-1.12, Data service options for spread spectrum systems: cdma2000 high speed packet data service option 33, Ballot version, December 1999.)

According to the standard of the above-mentioned references, the terminal sends a supplemental channel request message (hereinafter referred to as SCRM) to the base station to request the reverse SCH channel allocation. At this time, the terminal specifically indicates the value requested by the terminal in the DURATION and PREFERRED_RATE fields in the REQ_BLOB field of the SCRM message. The terminal also indicates pilot strengths such as active sets and other candidate sets. Then, the base station receiving the SCRM message determines the allocation of the reverse SCH to the terminal requesting the allocation of the additional channel based on the information, and the information related to the channel allocation is referred to as an Extended Supplemental Channel Assignment Message: The terminal is informed via an ESCAM) or a handoff decision message (hereinafter referred to as UHDM). Then, the terminal receiving the ESCAM or UHDM message allocates the additional channel during the allotted time and transmits the data.

The prior art allocation process of the reverse side additional channel is shown in FIG. In this state, dedicated channels are allocated between the terminal and the base station to communicate with each other. That is, forward and reverse dedicated control channels are allocated.

Referring to FIG. 1, when the additional channel allocation of the reverse link is required, the terminal generates an SCRM message including the allocation time of the reverse channel in step 111 and transmits the SCRM message to the base station through the reverse dedicated control channel. Then, the base station receiving the message through the reverse dedicated control channel analyzes channel allocation request information included in the SCRM message and, if possible, allocates an additional channel, the ESCAM message including allocation information of the reverse additional channel possible. After generating, in step 113, it transmits through a forward dedicated control channel. Then, the terminal receives an ESCAM message received through the forward dedicated control channel, allocates a reverse additional channel, and transmits a message of the terminal through the reverse additional channel in step 115.

However, the above-described conventional standard does not specifically define a method for allocating a reverse SCH channel based on additional channel allocation information requested by a terminal in a base station subsystem. That is, in the conventional standard, there is no mention of how long the base station, which is required to allocate the uplink additional channel from the terminal, should be assigned the uplink additional channel for no time, and this part may have different implementation issues. have.

Accordingly, an object of the present invention is to provide a method in which a base station can efficiently allocate a reverse additional channel according to a request for assigning a reverse additional channel in a code division multiple access communication system.

The method of allocating a mobile station is a reverse supplemental channel of a communication system according to the present invention for achieving the above object, when the channel assignment request from a terminal, using the process to obtain the capacity R _Available the available channels and the available A process of determining whether to accept the additional channel allocation by comparing the channel capacity R _Available and the spare channel capacity; and when the allocation of the additional channel is accepted, the available channel capacity R _Available and the rate R of the additional channel requested by the terminal. comparing the _mobile, and comparing the current channel occupancy rate R _Current and the channel capacity reference value R _Threshold; and, if the R _Available is greater than the R _mobile and the R _Current is greater than the R _Threshold , the request is made. Assigns an additional channel of a predetermined transmission rate, and if any one of the two comparison values is small, the requested transmission To generate more additional channel assignment message containing the process and information of the additional channel is assigned to the assignment of an additional channel comprises a low transmission rate and transmitting to the terminal.

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

The present invention relates to a method for allocating a reverse additional channel by a base station according to an additional channel allocation request of a terminal. In an embodiment of the present invention, the mobile station (MS) requests a base station (BSS: base station subsystem) to allocate a reverse additional channel R-SCH, and transmits data through the allocated R-SCH. Thereafter, when there is no more data to transmit, the UE requests for the release of the R-SCH. In this case, the terminal will request that the base station additionally requests the base station only once, and if there is no data to be transmitted after completing the data transmission, it is assumed that the request for the release of the reverse side channel.

2 is a diagram illustrating an operation between a base station and a terminal for allocating a reverse additional channel according to an embodiment of the present invention. The base station subsystem (BSS) includes a base station controller (BSC) 202 and a base transceiver station (BTS) 204.

Referring to FIG. 2, the terminal 206 transmits an additional channel request message SCRM (Supplemental Channel Request Message) to the base station transceiver 204 when it is necessary to use the reverse additional channel (when data transmission of the reverse link is required). The base station transceiver 204 then forwards it to the base station controller 202. Then, the call processor of the base station controller 202 analyzes the SCRM and requests allocation of a reverse additional channel to the channel manager of the base transceiver station 204. Then, the channel manager of the base station transceiver 204 checks the current state of the reverse side additional channel and allocates an available reverse side additional channel, and notifies the call processor of the base station controller 202. Then, the base station controller 202 generates an extended channel assignment message ESCAM (Extended Supplemetal Channel Assignment Message) including the information of the allocated uplink additional channel and notifies the terminal side. When the reverse additional channel is allocated as described above, the additional channel is established between the terminal 206 and the base station transceiver 204 to perform data communication.

In the following description, the base station controller BSC and the base station transceiver BTS will be referred to as a base station BSS.

An embodiment of the present invention relates to a method for allocating a reverse additional channel by a base station at the request of the terminal when a need arises for a terminal to transmit data through a reverse additional channel in a state in which a dedicated control channel is allocated. will be. In this state, the dedicated control channel is allocated, but the data transmission is stopped, so that the reverse additional channel may not be allocated. In addition, although the reverse side additional channel is already allocated to communicate with the base station and the terminal, there may be a case in which a state in which a larger capacity of the reverse side additional channel (or other reverse side channel) is required.

3 is a flowchart illustrating an allocation process and an operation example of the reverse side additional channel as described above.                     

When the reverse side additional channel allocation is required, the terminal first generates a message SCRM requesting allocation of the side channel and transmits it to the base station. At this time, the structure of the message SCRM is shown in Table 1 below.

field Bits  Size_of_REQ_BLOB  4  REQ_BLOB  8 * SIZE_OF_REQ_BLOB ---

Although the message SCRM includes many message fields, message fields for allocating a reverse side additional channel according to an embodiment of the present invention are SIZE_OF_REQ_BLOB and REQ_BLOB fields as shown in Table 1 below. In Table 1, the SIZE_OF_REQ_BLOB field represents the number of bytes of REQ_BLOB.

In addition, the REQ_BLOB field is a field in which information of a reverse side additional channel desired by the terminal is set. The structure of this field is shown in Table 2 below.

field Bits  DURATION_UNIT 3  NUM_REQ 3  RESERVED 2

As shown in the following <Table 3>, as many as the value of the NUM_REQ field.

 SR_ID 3  PREFERRED_RATE 4  DURATION 9

In Table 3, the R-SCH rate of the uplink additional channel desired by the terminal is set in PREFERRED_RATE, and the usage time of the uplink additional channel is set in DURATION.

When the terminal transmits the message SCRM to the base station as described above, the base station performs a process of allocating the reverse side additional channel when the terminal accepts the reverse side additional channel allocation request in step 313. The base station sets the reserve capacity of the reverse side additional channel to a constant value, and decreases the available capacity whenever the reverse side additional channel is allocated. Therefore, whether to accept the assignment of the uplink additional channel is determined by the capacity of the available additional channel. If the uplink additional channel is available for allocation, the corresponding additional channel is allocated if the additional channel having the requested transmission rate can be allocated within the available capacity range. As described above, if the uplink additional channel can be allocated according to the request of the terminal, the base station generates an additional channel assignment message ESCAM and transmits it to the terminal in step 315. At this time, if the terminal is in a handoff situation, the base station generates and transmits a handoff decision message UHDM.

The structure of the ESCAM / UHDM is shown in Table 4 below.

field Bits ---   NUM_REV_SCH  0 or 5

In Table 4, the NUM_REV_SCH field indicates the number of uplink additional channels allocated to one subscriber, followed by message fields as shown in Table 5 by the value of the NUM_REV_SCH field.

 REV_SCH_ID One  REV_SCH_DURATION 4  REV_SCH_START_TIME 0 or 5  REV_SCH_NUM_BITS_IDX 4

In Table 5, the REV_SCH_ID field is an identifier indicating a reverse subchannel, REV_SCH_DURATION represents a time when an allocated subchannel can be used, REV_SCH_START_TIME represents a start time of using the allocated subchannel, and REV_SCH_NUM_BITS_IDX represents a frame period. The number of data bits to be transmitted during the frame duration reflects the channel speed of the uplink secondary channel.

When the additional channel allocation message ESCAM receives the terminal, the terminal transmits a message through the additional channel for a specified time at a start time set according to the ESCAM message in step 317, and the transmission rate of the transmitted message is also the ESCAM. Determined according to the baud rate specified in. After transmitting the message as described above, the terminal [319] transmits and terminates the SCRM message for releasing the allocation of the reverse side additional channel in step 319.

As described above, the allocation process of the reverse side additional channel according to the embodiment of the present invention is as follows.

First, the terminal requests an R-SCH assignment from the base station through an SCRM message. Then, the base station operates an R-SCH scheduler of the uplink additional channel to determine whether to accept the R-SCH channel allocation request of the terminal, and if the R-SCH allocation is determined, Transmission Rate), the number of R-SCH, transmission time (Duration) and other parameters are determined. In an embodiment of the present invention, allocation parameters of the reverse side additional channel are specifically defined. Thereafter, the base station generates an ESCAM (or UHDM) message including the uplink allocation information and then notifies the terminal of this to instruct R-SCH allocation. The terminal receives the allocated R-SCH channel information and transmits data for an assigned transmission time at an assigned transmission rate. The terminal completes data transmission while performing the transmission as described above. Thereafter, since there is no more data to transmit, the base station requests R-SCH release from the SCRM message (the SIZE_OF_REQ_BLOB value is set to 0 and does not include the REQ_BLOB field).

As described above, the present invention basically determines whether the terminal accepts the R-SCH request and the R-SCH allocation amount with the help of the terminal (that is, with the help of the SCRM message transmitted from the terminal) by the method of operating in the base station. It is about a method. As shown in FIG. 2 and FIG. 3, when the terminal requests allocation of a reverse additional channel, the base station performs channel allocation if the request is accepted and if the terminal can accept the request. The base station looks at whether an R-SCH request is accepted and an R-SCH allocation method.

The base station first sets a reverse capacity of a reverse channel to a constant value based on 9.6 kbps, and whenever the reverse additional channel is allocated, the available channel capacity (R) is obtained by the following mapping example. Reduce the SCH capacity. In the R-SCH admission control, it is determined whether the requested data rate is acceptable within the remaining available channel capacity. Table 6 below shows an example of capacity contribution per channel in the cdma2000 system according to an embodiment of the present invention.

Channel speed Capacity Contribution Mark 9.6 kbps One R _9.6 19.2 kbps 2 R _19.2 38.4 kbps 4 R _38.4 76.8 kbps 8 R _76.8 153.6 kbps 16 R _153.6

이라고 하고, 각 채널 별로 현재 사용 중인 채널 수를 각각 N_9.6, N_19.2, N_38.4, N_76.8, N_153.6 이라고 하면, 가용한 채널용량 R_Available은 다음의 <수학식 1>과 같이 구할 수 있다.The backward capacity contribution calculated in <Table 6> should be a value considering the interference coming from the terminal of the neighbor cell. The channel capacity of the reverse link

If the number of channels currently used for each channel is N _9.6 , N _19.2 , N _38.4 , N _76.8 , N _153.6 , the available channel capacity R _Available can be obtained as shown in Equation 1 below.

In Equation 1, alpha _1 to (0 alpha <= 1) are values for considering a FDCH (Fundamental Dedicated Channel), voice, and the like, and different values according to the case where the SCH, FDCH, and voice are occupied. It is to reflect this because it becomes. Then, whether the UE accepts the R-SCH request is determined by Equation 2 below.                     

Next, a method of determining an R-SCH allocation amount in a base station according to an R-SCH request amount of a UE that has received a request will be described. If the transmission rate required by the terminal is called R _Mobile and the channel occupancy capacity currently being used in the cell is called R _Curent , the R-SCH transmission rate (R _ASSN ) to be allocated to the terminal under the following conditions Determine. In addition, the channel occupancy in the corresponding cell is gradually increased by placing a threshold value of the channel capacity, and a method of reducing the amount allocated to the terminal is further introduced when the channel capacity exceeds the _threshold value (R _Threshold ). The above procedure determines the quota according to Equation 3 below.

In Equation 3, n is an integer satisfying n> = 2. In this case, 2 is used as a representative value.

The above process is shown in FIG. 4 as a flowchart.

Referring to FIG. 4, if the UE first transmits an SCRM message, the BS receives the SCRM message in step 412. Upon receiving the SCRM message, the base station determines the available channel capacity R _Available by Equation 1 based on the information included in the received SCRM message, the radio state of the current cell, the channel occupancy state, and the like in step 414. The calculation determines whether to accept the R-SCH request based on this value. In this case, if the available channel capacity is not satisfied, the terminal informs the terminal of the inability to allocate the uplink additional channel and returns to step 412 to prepare for the next state. However, if the uplink additional channel is available for allocation, the base station performs steps 416 to 422 to determine the R-SCH allocation only for the received R-SCH request. The allocation of the R-SCH is determined in steps 416 and 418, and the method of determining is performed in the same manner as in Equation 3 above. That is, if the rate R _Mobile of the uplink additional channel required by the terminal has a value lower than the available channel capacity R _Available , or if the channel occupancy rate R _Curent currently being used is lower than the channel _threshold value (R _Threshold ), The base station allocates the _mobile station to service the transmission rate R _Mobile requested by the terminal. However, if either of the two conditions is not satisfied, the base station allocates an additional channel having a lower transmission rate than the transmission rate requested by the terminal.

As described above, when the base station allocates the uplink additional channel, if the channel margin is sufficient (when the above condition is satisfied in Equation 3), the base station proceeds to step 420 and according to the R-SCH request amount requested by the terminal. If all of them are allocated, and the channel margin is not sufficient (when the following condition is satisfied in Equation 3), the allocation is made smaller than the R-SCH required by the UE according to Equation 3 in step 422. do. Thereafter, the base station generates an ESCAM message including the information of the uplink additional channel allocated as described above, and then notifies the terminal in step 424.

As described above, when a base station allocates a reverse side additional channel at the request of a terminal, there is an advantage in that an R-SCH channel can be efficiently operated in a reverse link to increase efficiency of network resources.

Claims (8)

A method for allocating a reverse additional channel by a base station of a mobile communication system, Obtaining a capacity of a usable channel when a terminal allocates a channel; Allocating an additional channel of the requested rate when the available channel capacity is larger than a transmission rate of the additional channel requested by the terminal; otherwise, allocating an additional channel having a lower rate than the required rate; And generating an additional channel assignment message including the allocated additional channel information and transmitting the additional channel assignment message to the terminal. According to claim 1, wherein the channel rates are 9.6kbps, 19.2kbps, 38.4kbps, 76.8kps, 153.6kbps, the available additional channel capacity of the base station, characterized in that determined by the following equation (4) Assignment method.

In Equation 4, R _Total is the channel capacity of the reverse link, R _9.6 , R _19.2 , R _38.4 , R _76.8, R _153.6 is the channel capacity contribution, N _9.6 , N _19.2 , N _38.4 , N _76.8 , N _153.6 The number of channels currently in use for each bitrate, The method of claim 2, wherein the channel contribution is R _9.6 = 1, R _19.2 = 2, R _38.4 = 4, R _76.8 = 8, and R _153.6 = 16. 3. The method of claim 2, wherein the additional channel is allocated by Equation (5).

The R _mobile is a transmission rate required by the terminal, the R _Available is an available channel transmission rate, the R _ASSN is an allocated transmission rate R _current is the channel occupancy rate in use in the cell, R _{Threshol ??} Is a reference value of channel capacity. A method for allocating a reverse additional channel by a base station of a mobile communication system, When the channel allocation request from the terminal, the process to obtain the R _Available capacity of the available channels and, Determining whether to accept the additional channel allocation by comparing the available channel capacity R _Available and the spare channel capacity; When accepting the allocation of the additional channel, a process of comparing the available channel capacity R _Available and the transmission rate R _mobile of the additional channel requested by the terminal, and comparing the current channel occupancy rate R _Current and the channel capacity reference value R _Threshold . and, In the comparing process, if the R _Available is larger than the R _mobile and the R _Current is larger than the R _Threshold , the additional channel of the requested transmission rate is allocated. If any one of the two comparison values is smaller, the lower transmission rate is lower than the required transmission rate. Allocating an additional channel of a data rate; And generating an additional channel assignment message including the allocated additional channel information and transmitting the additional channel assignment message to the terminal. The reverse additional channel of the base station according to claim 5, wherein the channel rates are 9.6 kbps, 19.2 kbps, 38.4 kbps, 76.8 kbps, 153.6 kbps, and the available channel capacity is determined by Equation 6 below. Assignment method.

In Equation 6, R _Total is the channel capacity of the reverse link, R _9.6 , R _19.2 , R _38.4 , R _76.8, R _153.6 is the channel capacity contribution, N _9.6 , N _19.2 , N _38.4 , N _76.8 , N _153.6 The number of channels currently in use for each bitrate, The base station of claim 5, wherein the reserved channel capacity is determined as a constant value R _9.6 based on _9.6 Kbps, and whether to accept the allocation of the additional channel is determined by Equation 7 below. Channel assignment method.

The method of claim 5, wherein the allocation of the additional channel is performed by Equation (8) below.

The R _ASSN is the transmission rate of the allocated additional channel

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