KR101288880B1 - Call Setup Method for HSDPA Communication System - Google Patents

Abstract

A call establishment method in a communication system using a high speed downlink packet access method is presented.

The call setup method of the present invention consists of a call setup process and an RAB parameter optimization process, which extends a combination of transmission rates allocated to DPCH and HS-PDSCH of an interactive class or a background class for optimization of RAB parameters, and specifies a specified time. Adjusts the transmission rate allocated to the uplink DPCH in consideration of the average downlink packet amount transmitted to the mobile communication terminal during the period, or compares the uplink DPCH transmission rate to the initially allocated uplink DPCH transmission rate for a specified time. Determine whether to recrystallize.

According to the present invention, the maximum number of mobile communication terminals per channel card can be maximized, and a low transmission rate is allocated to the uplink DPCH for the mobile communication terminal that maintains the call connection in the HSDPA method but does not actually use the data. In addition, by assigning a high transmission rate to the uplink DPCH for a mobile communication terminal requiring a lot of data, it is possible to efficiently manage channel resources and prevent resources from wasting resources.

HSDPA, DPCH, RAB Parameters

Description

Call setup method for communication system using high speed downlink packet access method {Call Setup Method for HSDPA Communication System}

1 is a flowchart illustrating a general call setup method in a communication system using a high speed downlink packet access scheme;

2 is a flowchart illustrating a call setup method in a communication system using a fast downlink packet access scheme according to the present invention;

3 is a flowchart illustrating an embodiment of a process of optimizing a radio bearer parameter in a call setup method shown in FIG. 2;

4 is a flowchart illustrating another embodiment of a process of optimizing a radio bearer parameter in a call setup method shown in FIG. 2.

The present invention relates to a call setup method in a communication system, and more particularly, to a call setup method in a communication system using a high speed downlink packet access method.

Recently, a high speed downlink packet access (HSDPA) standard that provides a data rate of up to 10 Mbps for high speed packet data service in a wireless mobile environment has been developed and commercialized. The HSDPA service is a transport channel called a high speed downlink shared channel (HS-DSCH) for high speed downlink packet data service in the same frequency band (5 MHz) as in the existing Release 99 and Release 4 and a high speed shared control channel (HS) to support the same. It is a service that enables high-speed packet data transmission within a range that does not affect the existing system by defining control channels such as -SCCH) and high-speed dedicated physical control channel (HS-DPCCH).

In HSDPA, a hybrid automatic repeat request (HARQ) function in which a terminal receiving packet data from the node B informs the node B whether the packet data has been successfully received and causes the node B to retransmit the packet if necessary. In addition, it adopts the Adaptive Modulation and Coding (AMC) function, which modulates the modulation method according to the downlink situation, and in order to use these functions efficiently, most radio resource control functions including scheduling This is done at Node B.

In HSDPA, high speed dedicated physical control channel (HS-DPCCH), high speed downlink shared channel (HS-DSCH), and HS-PDSCH (HS-DSCH) are used to enable downlink high-speed packet data transmission without affecting existing communication systems. Links such as High Speed Physical Downlink Shared Channel (HS-SCCH) and High Speed Shared Control Channel (HS-SCCH) were added. The HS-DPCCH is an uplink channel used by each UE to feed back modulation and encoding information suitable for the channel situation by selecting a base station having the best downlink pilot channel condition, and the HS-DSCH and HS-PDSCH are provided through the HS-DPCCH. A downlink channel is used for transmitting packet data to a selected terminal in consideration of the information transmitted to the base station, the amount of transmission power that can be used for packet data transmission, and the number of channelization codes that can be used for packet data transmission. The HS-SCCH is a downlink channel used by the base station to transmit control information necessary for the terminal to receive packet data transmitted through the HS-DSCH and control information for other purposes.

In addition, in addition to the channel described above, in the HSDPA, a dedicated physical channel (DPCH) for informing that the base station has data to be received by the terminal in the future is used.

In the HSDPA type communication system, the amount of uplink traffic is proportionally increased or decreased according to the amount of downlink traffic. When the traffic is transmitted in the downlink, response information indicating whether the terminal normally receives the transmitted packet should be transmitted in the uplink because the response information also increases in proportion to the number of received packets. The response information is transmitted from the physical layer to the Node B through the HS-DPCCH, response information transmitted to the Radio Link Control (RLC) layer belonging to the radio network controller through the uplink DPCH, and belongs to the upper network of the radio network controller. There is response information transmitted to the Transmission Control Protocol / Internet Protocol (TCP / IP) layer.

3GPP defines a combination of HS-DSCH and uplink DPCH for HSDPA service. The UL DPCH and Radio Access Bearer (RAB) values are defined as 64 Kbps or 384 Kbps. A limitation of the number of DPCHs may occur, thus causing a problem in that the number of calls that can be supported by the HSDPA system is limited, and a limitation in managing radio resources efficiently.

1 is a flowchart illustrating a general call setup method in a communication system using a high speed downlink packet access method.

When the mobile communication terminal (UE) obtains the necessary system information through a cell selection process and transmits an RRC (Radio Resource Control) Connection Request message to the radio network controller (RNC) through the node B to request connection (S101), The wireless network controller determines whether the mobile communication terminal is connected or not, and transmits an RRC Connection Setup message to authorize the connection (S103).

Accordingly, the mobile communication terminal transmits an RRC Connection Setup Complete message to the radio network controller to report that the connection is completed (S105), and then transmits an Initial Direct Transfer message to request call setup (S107).

Upon receiving this, the wireless network controller requests call setup to the core network (CN) (S109), and after determining the RAB parameter, the core network transmits a RAB Assignment Request message to the wireless network controller and requests to allocate the RAB (S111). ). Here, the RAB parameter includes a maximum transmission rate, an authorized transmission rate, a traffic class indicating the type of call, and the like of the corresponding call. Traffic class includes Conversational class used for voice call, video call, and game, Streaming class used for streaming multimedia content, Interactive class used for wireless internet, and Background class used for content download. Therefore, if the call requested by the mobile communication terminal is a data service, the core network applies the Interactive or Background class to the RAB parameter.

Thereafter, the radio network controller transmits a Radio Link Setup Request message to the node B to establish a radio link (S113). Accordingly, the node B transmits a Radio Link Setup Response message to the radio network controller to establish a radio link. When reporting (S115), the radio network controller transmits a Radio Bearer Setup message to the mobile communication terminal to set up a radio bearer (S117). When the mobile communication terminal sets up the radio bearer and transmits a radio bearer setup complete message to the radio network controller and reports that the radio bearer setup is completed (S119), the radio network controller transmits a RAB assignment response message to the core network. Report that the call setup is complete (S121).

In the 3GPP standard specification, the combination of the transmission rate allocated to the DPCH and the HS-PDSCH of the interactive class or the background class to provide data services in the call setup process is currently limited to the following two cases.

1. Uplink: 64Kbps Downlink: [Maximum data rate based on terminal category]

2. Uplink: 384Kbps Downlink: [Maximum data rate based on terminal category]

As described above, since the transmission rate of the uplink DPCH is fixed to 64 or 384 Kbps in the channel card, the number of acceptable HSDPA calls per channel card is limited. For example, in the case of a channel card designed to accommodate 20 RABs of 64 Kbps or 8 RABs of 384 Kbps, it is impossible to set up HSDPA calls exceeding this number. The transmission rate is set to 64Kbps or 384Kbps, making it difficult to manage radio resources efficiently.

Therefore, a mobile communication terminal that maintains a connection of an HSDPA call but does not actually use data has a problem of wasting radio resources because it maintains an uplink DPCH radio access bearer allocated at 64 or 384 Kbps.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and is connected to a high-speed downlink packet access (HSDPA) communication system and uplinked according to a change in the amount of downlink packet data or uplink packet data of a mobile communication terminal using a data service. By controlling the transmission speed of the link DPCH, there is a technical problem in maximizing the number of HSDPA calls per channel card.

In order to achieve the above technical problem, an embodiment of the present invention extends a combination of a transmission rate allocated to an DPCH and an HS-PDSCH of an interactive class or a background class to provide a data service in an HSDPA type communication system, An appropriate uplink DPCH transmission rate is controlled according to the amount of downlink packet data. That is, the transmission rate allocated to the uplink DPCH is adjusted in consideration of the average downlink packet amount transmitted to the mobile communication terminal for a specified time.

On the other hand, according to another embodiment of the present invention, it is determined whether to re-determine the transmission rate by comparing the uplink DPCH transmission rate initially allocated to the amount of uplink packet data transmitted for a predetermined time in the HSDPA communication system.

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

2 is a flowchart illustrating a call setup method in a communication system using a fast downlink packet access method according to the present invention. The call setup method according to the present invention comprises a call setup process and an uplink DPCH RAB parameter optimization process. .

First, when a mobile communication terminal (UE) obtains necessary system information through a cell selection process and requests a connection to a radio network controller (RNC) through a node B (S201), the radio network controller grants access to the mobile communication terminal. It determines whether to apply the connection (S203). Accordingly, the mobile communication terminal reports that the connection is completed to the radio network controller (S205), and then requests call setup (S207).

Upon receiving the call establishment request, the radio network controller requests call establishment to the core network CN (S209), and after determining the RAB parameter, the core network requests to allocate the determined RAB to the radio network controller (S211). Here, the RAB parameter includes a maximum transmission rate, an authorized transmission rate, a traffic class indicating the type of call, and the like of the corresponding call. Traffic class includes Conversational class used for voice call, video call, and game, Streaming class used for streaming multimedia content, Interactive class used for wireless internet, and Background class used for content download. Therefore, if the call requested by the mobile communication terminal is a data service, the core network applies the Interactive or Background class to the RAB parameter.

Thereafter, the radio network controller causes the node B to establish a radio link with reference to the RAB parameter (S213). Accordingly, if the node B reports that the radio link is established to the radio network controller (S215), the radio network controller moves. The radio bearer is set to the communication terminal (S217). When the mobile communication terminal sets up the radio bearer and reports that the radio bearer setup is completed to the radio network controller (S219), the radio network controller reports that call setup is completed to the core network (S221). Accordingly, the mobile communication terminal and the communication system perform communication according to the transmission speed included in the predetermined RAB parameter.

In the present invention, in order to optimize the transmission rate of the uplink DPCH according to the amount of data transmitted through downlink and uplink when the radio bearer is allocated by the RAB parameter in the radio network controller, the data service is provided in an interactive or background class. The uplink transmission rate is added to the existing 64Kbps and 384Kbps so that 8, 16, 32, 128, 144Kbps can be allocated and optimized according to the amount of downlink and uplink data in the channel card. However, in order to determine the transmission rate, the amount of data transmitted and received between the mobile communication terminal and the mobile communication system must first be identified. Therefore, it is preferable to optimize the transmission rate according to the amount of data transmitted and received for a specified time after call setup is made.

Therefore, after the call setup is made between the mobile communication terminal and the core network in step S221, the radio network controller according to the downlink packet transmitted to the designated mobile communication terminal or the uplink packet transmitted to the radio network controller, that is, the uplink DPCH Optimize the transmission speed (S223), and reassigns uplink DPCH RAB parameters according to the optimized transmission rate (S225).

The reason for the optimization of the uplink DPCH RAB parameter is that the maximum data throughput of the downlink is determined according to the performance of each mobile communication terminal, that is, the UE category, and the feedback data amount of the uplink DPCH is proportional to the amount of downlink traffic. Because it increases and decreases. Table 1 shows the maximum data throughput that can be supported according to the terminal category.

[Table 1]

category Maximum number of HS-DSCH codes received Minimum TTI Interval Maximum number of HS-DSCH transport blocks received in the HS-DSCH TTI Total number of soft channel bits Category 1 5 3 7298 19200 Category 2 5 3 7298 28800 Category 3 5 2 7298 28800 Category 4 5 2 7298 38400 Category 5 5 One 7298 57600 Category 6 5 One 7298 67200 Category 7 10 One 14411 115200 Category 8 10 One 14411 134400 Category 9 15 One 20251 172800 Category 10 15 One 27952 172800 Category 11 5 2 3630 14400 Category 12 5 One 3630 28800

Since the traffic volume of the uplink increases and decreases proportionally according to the actual usage speed limited by the maximum transmission speed of the downlink terminal category shown in [Table 1], the optimization of the uplink by measuring the traffic volume of the downlink or the uplink The expected transmission rate can be predicted.

3 is a flowchart illustrating an embodiment of a process of optimizing a radio bearer parameter in a call setup method shown in FIG. 2.

For the present invention, the core network and the radio network controller use seven combinations of transmission rates allocated to the DPCH and the HS-PDSCH of the interactive class or the background class, for example.

1. Uplink: 64Kbps Downlink: [Maximum data rate based on terminal category]

2. Uplink: 384Kbps Downlink: [Maximum data rate based on terminal category]

3. Uplink: 8Kbps Downlink: [Maximum data rate based on terminal category]

4. Uplink: 16Kbps Downlink: [Maximum data rate based on terminal category]

5. Uplink: 32Kbps Downlink: [Maximum data rate based on terminal category]

6. Uplink: 128Kbps Downlink: [Maximum data rate based on terminal category]

7. Uplink: 144Kbps Downlink: [Maximum data rate based on terminal category]

The wireless network controller calculates an average amount of DL data AVG_D _DL by measuring the amount of data transmitted to the mobile communication terminal, that is, the amount of DL data D _DL , for a specified time T from the moment when call setup is completed. . Therefore, AVG_D _DL = D _DL / T (bps).

In addition, a variable (UR _DL ) (%) for determining the RAB parameter of the uplink DPCH in consideration of the downlink transmission rate is extracted, which is a value that varies according to the operator (S303).

Thereafter, the wireless network controller calculates a reference value for determining an uplink DPCH RAB parameter using the average DL data amount and a variable (S305). In this embodiment, the reference value RE_UR is determined by comparing the average DL data amount and a variable. It is calculated by the relation, that is, the average amount of downlink data satisfying the variable (RE_UR (bps) = AVG_D _DL * UR _DL ). When the reference value is calculated, compare the calculated reference value with the DPCH transmission rate list (8, 16, 32, 64, 128, 144, 384 Kbps) managed by the wireless network controller, and select the minimum value among the transmission rates larger than the reference value. The uplink DPCH RAB parameter to be allocated is determined (S307).

The uplink DPCH RAB parameter optimization process may be performed at a specified time period. For this purpose, the timer is driven after determining the uplink DPCH RAB parameter (S309), and when the timer driving is completed (S311), the process returns to step S301 and subsequent processes. Do this.

4 is a flowchart illustrating another embodiment of a process of optimizing a radio bearer parameter in a call setup method shown in FIG. 2.

Also in this case, as described in FIG. 3, the core network and the wireless network controller use the above seven combinations of transmission rates allocated to the DPCH and the HS-PDSCH of the interactive class or the background class.

The wireless network controller calculates an average UL data amount AVG_D _UL by measuring the data amount transmitted from the mobile communication terminal, that is, the UL data amount D _UL , for a specified time T from the moment when call setup is completed. . Therefore, AVG_D _UL = D _UL / T (bps) (S401).

In addition, a variable (UR _UL ) (%) for determining the RAB parameter of the uplink DPCH in consideration of the uplink transmission rate is extracted, which is a value that varies depending on the operator (S403).

Subsequently, the radio network controller calculates a comparison value X for determining an uplink DPCH RAB parameter using an average UL data amount and a pre-allocated transmission rate (S405). In this embodiment, the comparison value X ) Is calculated as a percentage of the average UL data amount to the currently allocated DPCH transmission rate (X = (AVG_D _UL / Gigabit allocation rate) * 100). When the comparison value is calculated, the calculated comparison value is compared with the previously extracted variable (S407). As a result of the comparison, when the comparison value is greater than or equal to the variable, the minimum transmission rate among the transmission rates larger than the average UL data amount per hour is determined as a transmission rate, that is, an uplink DPCH RAB parameter (S409).

The uplink DPCH RAB parameter optimization process can be performed at a specified time period. For this purpose, the timer is driven after determining the uplink DPCH RAB parameter (S411), and when the timer is completed (S413), the process returns to step S401 and subsequent processes. Do this. In addition, when the comparison value is smaller than the variable, that is, when it is not necessary to reallocate the current DPCH transmission rate, the process proceeds to step S411, in which uplink DPCH RAB parameter optimization is performed according to the subsequent data transmission amount. Prepare.

Thus, those skilled in the art will appreciate that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the embodiments described above are to be considered in all respects only as illustrative and not restrictive. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

As described above, the present invention extends the uplink DPCH transmission rate that can be allocated in a high speed downlink packet access communication system, and reassigns the transmission rate according to the amount of downlink data or the amount of uplink data. It is possible to maximize the number of mobile communication terminals that can be accommodated. In addition, it is possible to prevent waste of radio resources by allocating a low transmission rate to a mobile communication terminal that maintains a call connection using HSDPA but does not actually use data.

Claims (9)

A call setup method in a communication system of a high speed downlink packet access method, When the mobile communication terminal requests a connection to use a data service to a wireless network controller, the wireless network controller authorizing a connection of the mobile communication terminal; Reporting, by the mobile communication terminal, that the connection is completed to the wireless network controller, and requesting call setup, the wireless network controller requesting call setup to a core network; Requesting, by the core network, to assign a RAB to the radio network controller after determining a radio access bearer (RAB) parameter; Requesting, by the radio network controller, to establish a radio link to NodeB with reference to the RAB parameter; Requesting, by the radio network controller to establish a radio bearer to the mobile communication terminal, as the NodeB reports that it has established a radio link to a radio network controller; Reporting, by the mobile communication terminal, that the radio bearer setup is completed to the radio network controller after the radio bearer is established, reporting that call setup is completed to the core network; Optimizing an uplink dedicated physical channel (DPCH) transmission rate by referring to the amount of downlink data transmitted to the mobile communication terminal by the radio network controller; And Reallocating an uplink DPCH RAB parameter to the mobile terminal by an optimized transmission rate; The method may further include optimizing the uplink DPCH transmission rate based on a reference value and a list of DPCH transmission rates, or optimizing the uplink DPCH transmission rate based on a comparison value and a variable. A call setup method in a downlink packet access communication system. delete The method of claim 1, Optimizing the uplink DPCH transmission rate, The average amount of downlink data (AVG_D _DL = D _DL / T (bps) is measured by measuring the amount of data D _DL transmitted to the mobile communication terminal for a designated time T from the moment when the call setup is completed. Calculating)); Extracting the variable (UR _DL ) (%) for determining an RAB parameter of an uplink DPCH in consideration of a downlink transmission rate; Calculating the reference value RE_UR for determining an uplink DPCH RAB parameter using the average downlink data amount and the variable; And Comparing the reference value with the DPCH transmission rate list managed by the radio network controller, selecting a minimum value among transmission rates larger than the reference value, and determining the uplink DPCH RAB parameter to be reassigned; Call establishment method in a high-speed downlink packet access communication system comprising a. The method of claim 3, wherein The reference value RE_UR is calculated by multiplying the variable UR _DL by the average downlink data amount AVG_DDL. The method of claim 3, wherein Driving a timer after determining the uplink DPCH RAB parameter to be reassigned; And The method further comprises the step of returning to calculating the average amount of downlink data (AVG_D _DL = D _DL / T (bps)) when the timer is completed, and performing a subsequent process. Method of call setup in a wireless communication system. The method of claim 1, Optimizing the uplink DPCH transmission rate, The wireless network controller measures the data amount D _UL transmitted from the mobile communication terminal for a specified time T from the moment when the call setup is completed, and the average uplink data amount AVG_D _UL = D _UL / T (bps Calculating)); Extracting the variable (UR _UL ) (%) for determining an RAB parameter of an uplink DPCH in consideration of an uplink transmission rate; Calculating the comparison value (X) for determining an uplink DPCH RAB parameter using the average uplink data amount and a pre-allocated transmission rate; And Comparing the comparison value with the variable, and when the comparison value is greater than or equal to the variable, determining a minimum transmission rate among the transmission rates larger than the average uplink data amount per hour as an uplink DPCH RAB parameter to be reassigned; Call establishment method in a high-speed downlink packet access communication system comprising a. The method of claim 6, And the comparison value is calculated by a percentage of the average uplink data amount to the pre-allocated uplink DPCH transmission rate. The method of claim 6, Driving a timer after determining the uplink DPCH RAB parameter to be reassigned; And Returning to calculating the average amount of uplink data (AVG_D _UL = D _UL / T (bps)) when the timer is driven and proceeding thereafter; Call establishment method in a high-speed downlink packet access communication system characterized in that for further performing. 9. The method of claim 8, If the comparison value is smaller than the variable, the call setup method in the high-speed downlink packet access communication system characterized in that the step of driving the timer.

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