KR101003655B1 - Power allocation method and mobile communication system using the same - Google Patents

Abstract

The present invention relates to a power allocation method and a mobile communication system using the same.

According to an embodiment of the present invention, a method of allocating a cell may include measuring a load factor of a cell and using a power value provided by one of a base station and a wireless network controller according to the measured load factor. Allocating power to the.

Mobile Communications, HSDPA, Power Allocation, OVSF

Description

Power allocation method and mobile communication system using the same

The present invention relates to mobile communication, and more particularly, to a power allocation method for high speed downlink packet access and a mobile communication system using the same.

Recently, High Speed Downlink Packet Access (HSDPA) standards have been developed to provide data rates up to 10Mbps for high speed packet data services in mobile communication environments. The HSDPA service uses the same frequency bands as Release 99 and Release 4 of the 3rd Generation Partnership Project (3GPP), but uses separate channels to enable high-speed packet data transmission without affecting existing systems. .

To increase the transmission rate of HSDPA services, higher power should be allocated to the channels used for HSDPA services. However, when allocating high power, interference between adjacent cells may occur. In addition, since there is a limit to the power that can be allocated by the base station, when a high power is allocated to a channel used for the HSDPA service, an interference problem or a power distribution problem with another channel in the same cell may occur. Accordingly, there is a need for a power allocation technique for a channel used for the HSDPA service.

It is an object of the present invention to determine a power value to be allocated to a channel used for HSDPA service by a device dynamically determined according to a traffic channel in a cell among a base station and a wireless network controller.

In addition, an object of the present invention is to enable a device dynamically determined according to an OVSF code allocation rate in a cell between a base station and a wireless network controller to determine a power value to be allocated to a channel used for HSDPA service.

The objects of the present invention are not limited to the above-mentioned objects, and other objects that are not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, the power allocation method according to an embodiment of the present invention is to measure the load ratio of the cell, and using the power value provided by any one of the base station and the wireless network controller according to the measured load ratio Allocating power to a fast downlink packet access channel of a cell.

In order to achieve the above object, a mobile communication system according to an embodiment of the present invention is a wireless network controller for determining a power value control subject for the high-speed downlink packet access channel of the cell according to the load rate of the cell, and the wireless network controller And a base station for allocating power to the fast downlink packet access channel according to the determined power value control entity.

Specific details of other embodiments are included in the detailed description and the drawings.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and only the embodiments make the disclosure of the present invention complete, and the general knowledge in the art to which the present invention belongs. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

According to the power allocation method of the present invention as described above and the mobile communication system using the same, there is an effect that the appropriate power can be allocated to the HSDPA channel while reducing the possibility of inter-channel or inter-cell interference in a cell.

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

1 is a diagram illustrating a mobile communication system 100 according to an embodiment of the present invention. The mobile communication system 100 may include a radio access network (RAN) 10 and a core network 20. In the mobile communication system 100, the terminal 130 may be connected to the core network 20 through the wireless access network 10. That is, the terminal 130 is a communication device capable of performing wireless communication using the mobile communication system 100. An example of the terminal 130 is a mobile phone. However, embodiments of the terminal 130 are not limited to mobile phones, as the boundaries between digital devices become more flexible due to the development of digital technology. Accordingly, the terminal 130 may be implemented with other types of portable digital devices, such as personal digital assistants (PDAs) or notebook computers.

The radio access network 10 may include base stations 110-1, 110-2, and 110-3 and a radio network controller 120. The base stations 110-1, 110-2, and 110-3 may serve as a contact point between the wireless access network 10 and the terminal 130, and the wireless network controller 120 may be connected to the base station 110-1. , 110-2, 110-3) can be managed and controlled. In FIG. 1, three base stations 110-1, 110-2, and 110-3 are connected to the wireless network controller 120. This is not limited.

The wireless access network 10 may cover a geographical area that may be divided into cells, which are wireless communication areas that each of the base stations 110-1, 110-2, and 110-3 can support. One embodiment of the radio access network 10 may be a Universal Mobile Telecommunications (UTTS) Terrestrial Radio Access Network (UTRAN). The UTRAN may be based on Wideband Code Division Multiple Access (W-CDMA).

The radio access network 10 may accommodate a circuit switched service and a packet switched service. More specifically, when the wireless access network 10 supports a circuit switched service, the wireless network controller 120 uses a public switched telephone network (PSTN) and an integrated ISDN through a mobile switching center (MSC) 22. Services Digital network). In addition, when the radio access network 10 supports a packet switching service, the radio network controller 120 may serve a serving General Packet Radion Service (GPRS) Support Node (SGSN) 24 and a Gateway GPRS Support Node (Gateway). It may be connected to a packet switched network (eg, the Internet or an X-25 external network) via a GPRS Support Node (GGSN, not shown).

According to an embodiment of the present invention, the mobile communication system 100 may support High Speed Downlink Packet Access (HSDPA). To this end, an HSDPA channel may be used between the base stations 110-1, 110-2, and 110-3 and the terminal 130. In the present invention, the HSDPA channel includes a high speed dedicated physical control channel (HS-DPCCH), a high speed physical downlink shared channel (HS-PDSCH), and a high speed shared control channel (high speed). Shared Control Channel (HS-SCCH).

The HS-DPCCH is an uplink channel used by the terminal 130 to transmit feedback information to the base stations 110-1, 110-2, and 110-3. The feedback information includes modulation information and coding information suitable for channel conditions between the terminal 130 and the base stations 110-1, 110-2, and 110-3, and the base stations 110-1, 110-2, 110-3) may include information (ACK or NACK) on the successful reception of the packet data transmitted from. Meanwhile, the HS-PDSCH is a downlink channel used by the base stations 110-1, 110-2, and 110-3 to transmit packet data to the terminal 130 at high speed, and the HS-SCCH is transmitted through the HS-PDSCH. The base station 110-1, 110-2, or 110-3 is a downlink channel used to transmit the control information necessary for the terminal 130 to receive packet data and control information for other purposes to the terminal 130.

In the mobile communication system 100, a task of controlling a power value to be allocated to an HSDPA channel of each cell may be performed. According to one embodiment of the present invention, the power value to be allocated to the HSDPA channel may be controlled by the base station (110-1, 110-2, 110-3) or the wireless network controller 120. Which of the base stations 110-1, 110-2, 110-3 and the wireless network controller 120 is to operate as a power value control entity (the entity that determines the power value to assign to the HSDPA channel) is determined in each cell. It may be dynamically determined according to the load ratio (hereinafter referred to as cell load ratio).

In the present invention, the cell load rate includes at least one of a traffic channel occupancy rate and an Orthogonal Variable Spreading Factor (OVSF) code occupancy rate. For example, the power value allocated to 3GPP R99 based voice call service or video call service) is the ratio of the maximum power value supported by each of the base stations 110-1, 110-2, and 110-3. It may mean.

The power value control subject is determined according to the traffic channel occupancy, and the process of determining the power value to be allocated to the HSDPA channel is as follows.

In order to determine the power value control subject of the HSDPA channel, the base stations 110-1, 110-2, and 110-3 measure the traffic channel occupancy in the cell in charge of the HSDPA channel and transmit the measurement result to the wireless network controller 120. Can provide. This will be described with reference to FIG. 2.

2 is a flowchart illustrating a HSDPA call setup process according to an embodiment of the present invention. The base station indicated by the identification symbol '110' in FIG. 2 may be any one of the base stations 110-1, 110-2, and 110-3 shown in FIG. 1. In the present embodiment and the following embodiments, the identification symbol '110' is used to refer to the base station.

After obtaining the necessary system information through the cell selection process, the terminal 130 may request the access to the radio network controller 120 via the base station 110 (S205 and S210). A Radio Resource Control (RRC) Connection Request message may be used for the connection request.

According to the connection request of the terminal 130, the wireless network controller 120 may determine whether to grant the connection of the terminal 130. If the terminal 130 applies the connection, the wireless network controller 120 may notify the terminal 130 of the connection authorization via the base station 110 (S215, S220). The RRC Connection Setup message can be used to indicate the access authorization.

When the connection is authorized, the terminal 130 may inform the radio network controller 120 that the connection is completed via the base station 110 (S225 and S230). The RRC Connection Setup Complete message can be used to inform the completion of the connection.

Thereafter, the terminal 130 may request the HSDPA call setup from the radio network controller 120 via the base station 110 (S235 and S240). An Initial Direct Transfer message may be used for the HSDPA call establishment request.

The wireless network controller 120 which has received the request for the HSDPA call setup from the terminal 130 may request the HSDPA call setup from the core network 20 (S245), and the core network 20 may communicate with the terminal 130 and the radio bearer (Radio). A radio access bearer (RAB) assignment request message for forming a bearer may be transmitted to the radio network controller 120 (S250).

Thereafter, the radio network controller 120 instructs the base station 110 to transmit a Radio Link Setup Request message to establish a radio link (S255), and the base station 110 informs the radio network controller 120 after the radio link is established. The radio link setup response message may be transmitted to inform that the radio link is established (S260).

The radio network controller 120 may instruct the terminal 130 to set up a radio bearer by transmitting a Radio Bearer Setup message to the terminal 130 through the base station 110 (S265 and S270).

At this time, the terminal 130 may set up a radio bearer, and transmit a Radio Bearer Setup Complete message to the radio network controller 120 via the base station 110 to inform that the radio bearer setup is complete (S275, S280). .

Thereafter, the radio network controller 120 may transmit a RAB Assignment Response message to the core network 20 to inform that the radio bearer formation of the terminal 130 is completed (S285).

Thereafter, the base station 110 measures the traffic channel occupancy rate of the cell under its control (S290), and transmits the measured traffic channel occupancy rate to the radio network controller 120 (S295).

As mentioned above, the traffic channel occupancy may mean a ratio of the power value allocated to the remaining channels other than the HSDPA channel from the maximum power supported by the base station 110. The base station 110 measures the traffic channel occupancy (S290) and transmits the measurement result to the radio network controller 120 (S295) may be performed periodically while the HSDPA call is maintained. Of course, even if the HSDPA call is terminated, an embodiment in which processes S290 and S295 are continuously performed is possible. The measurement period of the traffic channel occupancy may vary depending on the embodiment.

In addition, process S290 and process S295 in Figure 2 does not mean that the new terminal should be performed independently each time to set up the HSDPA call. If at least one terminal forming an HSDPA call exists in a cell controlled by the base station 110, processes S290 and S295 may be performed due to the presence of a terminal previously forming an HSDPA call regardless of the HSDPA call setting of the new terminal. It may be ongoing.

Meanwhile, according to an embodiment of the present invention, even if there is no terminal forming an HSDPA call, the base station 110 may perform steps S290 and S295.

When the HSDPA session is formed through the process as shown in FIG. 2, the wireless network controller 120 may transmit the packet data received from the core network 20 to the base station 110, and the base station 110 may transmit the HSDPA channel. By using the packet data can be transmitted to the terminal 130.

The wireless network controller 120 provided with the traffic channel occupancy rate from the base station 110 may determine a power value control entity for the HSDPA channel of the cell controlled by the base station 110 according to the traffic channel occupancy rate.

3 is a flowchart illustrating a process of determining a power value control subject of an HSDPA channel according to an embodiment of the present invention.

When the traffic channel occupancy is transmitted from the base station 110 (S310), the wireless network controller 120 may determine whether the traffic channel occupancy is greater than a preset threshold (S320).

If the traffic channel occupancy is greater than the threshold, the wireless network controller 120 may determine the power value control entity of the HSDPA channel in the cell controlled by the base station 110 as the wireless network controller 120 itself (S330). .

However, if it is determined in step S320 that the traffic channel occupancy is not greater than the threshold, the wireless network controller 120 may determine the power value control entity of the HSDPA channel in the cell controlled by the base station 110 as the base station 110 ( S340).

 When the power value control subject is determined, the wireless network controller 120 may transmit information about the power value control subject to the base station 110 (S350).

3 may be repeatedly performed. Of course, when FIG. 3 is repeatedly performed, process S350 may be omitted if the previously determined power value control subject and the newly determined power value control subject are the same. For example, in a state where the base station 110 is operating as a power value controlling entity, if the power value controlling entity is determined as the base station 110 as a result of performing step S340, step S350 is omitted, and as a result of performing step S330 When the value controlling entity is determined by the wireless network controller 120, an embodiment in which process S350 is performed is possible.

According to the embodiment of FIG. 3, the wireless network controller 120 determines a power value control entity for a specific cell using the traffic channel occupancy of the cell. In this case, the radio network controller 120 may independently determine a power value control entity for each cell controlled by the base stations connected thereto.

However, the present invention is not limited by the embodiment of FIG. According to an embodiment of the present invention, the wireless network controller 120 may determine a power value control subject for the HSDPA channel in a cell controlled by each base station by comprehensively considering the traffic channel occupancy transmitted from the various base stations.

For example, in the mobile communication system 100 shown in FIG. 1, if the first traffic channel occupancy transmitted from the first base station 110-1 is not greater than the first threshold, the wireless network controller 120 may determine the first base station. The power base station 110-1 determines the power value control entity for the HSDPA channel of the first cell, which is controlled by 110-1, and the first traffic channel occupancy is the second threshold (the value greater than the first threshold). If greater, the wireless network controller 120 may determine the power value control entity for the HSDPA channel of the first cell as the wireless network controller 120 itself.

However, if the first traffic channel occupancy is greater than the first threshold but not greater than the second threshold, the radio network controller 120 is transmitted from the second base station 110-2 that controls the second cell adjacent to the first cell. The power value control entity for the HSDPA channel of the first cell may be determined according to the second traffic channel occupancy. If the second traffic channel occupancy is not greater than or greater than the second threshold, the wireless network controller 120 may determine the power value controlling entity for the HSDPA channel of the first cell as the wireless network controller 120 itself. However, if the second traffic channel occupancy is not greater than the second threshold, the wireless network controller 120 may determine the power value controlling entity for the HSDPA channel of the first cell as the first base station 110-1. Accordingly, when the first traffic channel occupancy is greater than the first threshold and the power value controlling entity is determined by the wireless network controller 120, when the first traffic channel occupancy approaches the first threshold, the wireless network controller 120 By increasing the power value without considering the situation of the adjacent cell (second cell), it is possible to reduce the possibility of interference between the first cell and the second cell.

In the above description, the power value control entity for the HSDPA channel is individually determined for each cell, but the present invention is not limited thereto. According to an embodiment of the present invention, the radio network controller 120 may collectively determine a power value control entity for the HSDPA channel for all cells of the radio access network 10. For example, when the total sum of the traffic channel occupancy of each cell constituting the radio access network 10 is less than the threshold, or when the cell whose traffic channel occupancy is less than the threshold is more than a certain ratio, the radio network controller 120 is wireless. Power value control entities for HSDPA channels of all cells in the access network 10 may be determined as the base stations 110-1, 110-2, and 110-3, respectively. In addition, when the total sum of the traffic channel occupancy of each cell constituting the radio access network 10 is greater than or equal to the threshold, or when the cell whose traffic channel occupancy is smaller than the threshold is smaller than a certain ratio, the radio network controller 120 determines the HSDPA of each cell. The power value controlling entity for the channel may be determined as the radio network controller 120 itself.

In addition, there may be various embodiments for dynamically determining a power value control subject for the HSDPA channel according to the traffic channel occupancy in each cell, which should be construed as being within the scope of the present invention.

When the power value control entity is determined, an operation of allocating power of the HSDPA channel may be performed. If the power value controlling entity is the wireless network controller 120, the base station 110 may allocate power to the HSDPA channel according to the power value determined by the wireless network controller 120. That is, the base station 110 allocates power to the HSDPA channel within a range not exceeding the power value determined by the wireless network controller 120, and the maximum power value that the base station 110 can support is the wireless network controller 120. Is changed to the determined power value.

On the other hand, if the power value control entity is the base station 110, the base station 110 determines the power value to be allocated to the HSDPA channel by itself. In this case, the base station 110 may allocate the maximum power granted to the HSDPA channel, and may adjust the power value with reference to the measured traffic channel occupancy and allocate the power to the HSDPA channel. Here, the maximum power granted to the base station 110 may be a value previously set by the mobile communication system manager.

4 is a flowchart illustrating a power allocation process according to an embodiment of the present invention. This embodiment shows a case where the power value controlling entity is the base station 110.

When the wireless network controller 120 transmits information on the power value controlling entity to the base station 110 (S410), the base station 110 needs to determine the power value directly through the information on the power value controlling entity. Able to know.

The base station 110 may measure the traffic channel occupancy rate in the cell according to a predetermined period (S420), and determine a power value to be allocated to the HSDPA channel according to the measured traffic channel occupancy rate (S430).

Thereafter, the base station 110 may allocate power to the HSDPA channel according to the power value determined in step S430 (S440).

In FIG. 4, process S420 is not necessarily performed between processes S410 and S430. For example, if the measurement period of the traffic channel occupancy has not yet arrived, step S420 and step S420 are omitted, and in step S430, the base station 110 may use the previously measured traffic channel occupancy rate. Of course, since the traffic channel occupancy may be measured periodically, if the power value controlling entity is not changed to the wireless network controller 110, processes S420 to S440 may be repeatedly performed.

Although not shown in FIG. 4, the base station 110 may transmit the traffic channel occupancy measured in step S420 to the radio network controller 120, and the radio network controller 120 uses the same to determine the power value control subject again. Can be. If the power value control entity is determined by the wireless network controller 120, the process of FIG. 5 may be performed.

5 is a flowchart illustrating a power allocation process according to another embodiment of the present invention. This embodiment shows a case where the power value control entity is the wireless network controller 120.

When the wireless network controller 120 transmits information on the power value controlling entity to the base station 110 (S510), the base station 110 cannot determine the power value directly through the information on the power value controlling entity. Able to know.

Since the power value controlling entity is the wireless network controller 120, the base station 110 may wait for transmission of the power value of the wireless network controller 120. In addition, the wireless network controller 120 may determine a power value to be allocated to the HSDPA channel according to the traffic channel occupancy transmitted from the base station 110 (S520).

Thereafter, the wireless network controller 120 may transmit the power value determined in step S520 to the base station 110 (S530), and the base station 110 transmits to the HSDPA channel according to the power value transmitted from the wireless network controller 120. Power may be allocated (S540).

Although not shown in FIG. 5, the base station 110 may periodically measure the traffic channel occupancy rate and transmit the measurement result to the radio network controller 120, and processes S520 to S530 may be repeatedly performed using the same. .

Of course, as described with reference to FIG. 3, the wireless network controller 120 may determine a power value control subject using the traffic channel occupancy transmitted from the base station 110. If the power value controlling entity is determined as the base station 110, the process of FIG. 4 may be performed.

The power value to be allocated to the HSDPA channel may be determined according to the traffic channel occupancy. Preferably, the higher the traffic channel occupancy, the lower the power value to be allocated to the HSDPA channel, and the lower the traffic channel occupancy, the higher the power value to be allocated to the HSDPA channel. The information on the power value to be allocated to the HSDPA channel according to the traffic channel occupancy may be set in the base station 110 and the wireless network controller 120 to a value that can efficiently use radio resources through a preliminary experiment.

When the base station 110 determines the power value to be allocated to the HSDPA channel, the base station 110 may use the traffic channel occupancy in the cell that it has jurisdiction. However, when the wireless network controller 120 determines a power value to be allocated to the HSDPA channel, the wireless network controller 120 may use not only the traffic channel occupancy of a specific cell but also the traffic channel occupancy of an adjacent cell.

For example, according to the first traffic channel occupancy rate transmitted from the first base station 110-1, the radio network controller 120 may allocate power to the HSDPA channel of the first cell controlled by the first base station 110-1. The value can be determined primarily. Thereafter, the radio network controller 120 determines the first HSDPA channel of the first cell according to the second traffic channel occupancy transmitted from the second base station 110-2 adjacent to the first base station 110-1. The power value can be corrected. Preferably, the lower the second traffic channel occupancy, the lower the primary determined power value. For example, if the second traffic channel occupancy is greater than the preset threshold, the first determined power value is used. If the second traffic channel occupancy is not greater than the threshold, the power value determined primarily according to the second traffic channel occupancy. Can be lowered by a certain ratio. Here, the rate of decrease of the power value determined primarily according to the threshold value or the second traffic channel occupancy may be set to a value capable of minimizing interference between cells or other channels in the cell through a preliminary experiment.

Table 1 shows an example of parameters that can be used to implement the embodiments as described above.

Table 1

parameter range unit Automatic control Activation / deactivation - Reporting level 0-100 % Power 320-450 * 0.1dB Power 320-450 * 0.1dB Periodic report On / Off - Cycle 1-1000 second

 Among the parameters exemplified in Table 1, 'automatic control status' indicates whether to dynamically set a power value control subject for the HSDPA channel. If the 'automatic control whether' parameter is set to the active state, as described above, the power value control subject may be dynamically changed to the base station or the wireless network controller according to the traffic channel occupancy. If the 'automatic control whether' parameter is set to the deactivated state, as in the prior art, any one of the base station 110 and the wireless network controller 120 to determine the power value continuously.

The 'report level' parameter indicates a reporting unit of traffic channel occupancy. For example, if the reporting level is set to 10%, the base station 110 may report the traffic channel occupancy to the radio network controller 120 in 10% units.

The 'maximum power' parameter and the 'minimum power' parameter indicate the range of power values that can be present. Accordingly, the power value controller may determine the power value within a range from the value of the 'minimum power' parameter to the value of the 'maximum power' parameter.

The 'periodical reporting' parameter indicates whether the base station 110 periodically reports the traffic channel occupancy rate to the radio network controller 120, and the 'period' parameter indicates a reporting interval when periodically reporting the traffic channel occupancy rate. Indicates. If the 'periodic reporting' parameter is set to On and the 'period' parameter is set to 10, the base station 110 may transmit the traffic channel occupancy rate to the wireless network controller 120 every 10 seconds.

These parameters may be set in the base station 110 and the radio network controller 120 by the mobile communication system administrator. Of course, since the parameters of Table 1 are exemplary, only some of the parameters of Table 1 may be set or parameters other than those illustrated in Table 1 may be set.

If the 'Reporting Level' is set to 10%, 'Maximum Power' is set to 430 * 0.1dB, and 'Minimum Power' is set to 380 * 0.1dB, the information table can be used to determine the power value. An example is shown in Table 2. The base station 110 or the wireless network controller 120 may determine the power value using the information table of Table 2.

[Table 2]

Report level (10% / 1 level) Power value (0.1 dB) 0%-9% 430 10%-19% 420 20%-29% 410 30%-39% 400 40%-49% 390 50% or more 380

Of course, the wireless network controller 120 may determine the power value in a similar manner.

In the above description, the power value to be allocated to the HSDPA channel of each cell is controlled by using the traffic channel occupancy. As described above, in the mobile communication system 100 according to the embodiment of the present invention, an orthogonal variable spreading element (OVSF) is used. ; Orthogonal Variable Spreading Factor) The power value to be allocated to the HSDPA channel may be controlled according to the allocation ratio of the code.

6 is a diagram illustrating whether the OVSF code is occupied according to an embodiment of the present invention.

An OVSF is a set of spreading codes derived from a set of orthogonal codes of a tree structure and used for channelization. The OVSF code is assigned a unique value to each terminal to transmit data. Accordingly, a plurality of terminals existing in the same cell can transmit and receive data with orthogonality to the channel.

That is, the OVSF code is a code that creates orthogonality between channels in one radio cell. In order to maintain orthogonality between forward channels, terminals adjust and transmit a transmission time according to the OVSF code.

As shown in FIG. 6, the OVSF code is generated in a tree structure for each SF layer. The generated OVSF code is assigned to a terminal so that the terminal performs orthogonal transmission using the same.

On the other hand, when one OVSF code is occupied by a specific terminal, all OVSF codes existing in a lower layer of the OVSF code may not be occupied by any terminal. For example, if C _{ch , 2,0} = 1 1 code 610 is occupied by a particular terminal, C _{ch , 4,0} = 1 1 1 1 code 620 and all codes in the lower layer, and C _{ch , 4,1} = 1 1 -1 -1 Code 630 and all the codes in its lower layer cannot be occupied by any terminal.

In addition, the mobile communication system administrator may determine the SF for each terminal or for each type of data to be transmitted, so that a code occupied and an unoccupied code coexist in one SF layer.

The OVSF code is generated and managed by a base station or a wireless network controller for each wireless cell. A device among the base stations 110-1, 110-2, and 110-3 and the wireless network controller 120 is a power value controlling entity ( Whether to operate as a subject to determine the power value to be allocated to the HSDPA channel may be dynamically determined according to the OVSF code occupancy rate in each cell.

Here, the OVSF code occupancy rate represents the ratio of the OVSF code occupied by the terminal to perform data transmission / reception with respect to the number of generated OVSF codes. May be determined by a mobile communication system administrator. For example, if there is a separate OVSF code allocated exclusively for HSDPA, the remaining OVSF code except for the OVSF code allocated exclusively for HSDPA is determined, and the ratio of the OVSF codes occupied by the terminal is OVSF code. It can be calculated by the share. In addition, the calculation target OVSF code may indicate an OVSF code existing in all SF layers, or may indicate only an OVSF code existing in a specific SF layer.

FIG. 7 is a diagram illustrating whether to assign an OVSF code to HSDPA only according to an embodiment of the present invention. FIG.

The mobile communication system manager divides the OVSF code for each SF, allocates a specific group of OVSF codes 710 to HSDPA, and allocates the remaining codes 720 for channels other than HSDPA. In this case, the OVSF code 710 having a specific code number may be allocated to the HSDPA only, and the criterion may be changed for each SF.

Meanwhile, FIG. 7 shows that the OVSF codes 710 and 720 are divided into two groups, but is divided into three, four, or more groups, and at least one specific group may be allocated to HSDPA only. Of course.

In order to determine the power value control subject of the HSDPA channel, the base stations 110-1, 110-2, and 110-3 measure the OVSF code occupancy rate in the cell in charge of the HSDPA channel and transmit the measurement result to the wireless network controller 120. Can provide.

The wireless network controller 120 provided with the OVSF code occupancy rate from the base station 110 may determine a power value control entity for the HSDPA channel of a cell controlled by the base station 110 according to the OVSF code occupancy rate.

8 is a flowchart illustrating a process of determining a power value control subject of an HSDPA channel according to another embodiment of the present invention.

When the OVSF code occupancy is transmitted from the base station 110 (S810), the wireless network controller 120 may determine whether the OVSF code occupancy is greater than a preset threshold (S820).

If the OVSF code occupancy is greater than the threshold, the wireless network controller 120 may determine the power value control entity of the HSDPA channel in the cell controlled by the base station 110 as the wireless network controller 120 itself (S830). .

However, if it is determined in step S820 that the OVSF code occupancy is not greater than the threshold, the radio network controller 120 may determine the power value control entity of the HSDPA channel in the cell controlled by the base station 110 as the base station 110. (S840).

When the power value control entity is determined, the wireless network controller 120 may transmit information about the power value control entity to the base station 110 (S850).

8 may be repeatedly performed. Of course, when FIG. 8 is repeatedly performed, process S850 may be omitted if the previously determined power value control subject and the newly determined power value control subject are the same. For example, in a state where the base station 110 is operating as a power value controlling entity, if the power value controlling entity is determined as the base station 110 as a result of performing step S840, step S850 is omitted and the resultant power value of performing step S830 is performed. When the control entity is determined by the wireless network controller 120, an embodiment in which process S850 is performed is possible.

According to the embodiment of FIG. 8, the wireless network controller 120 determines a power value control entity for a specific cell using the OVSF code occupancy of the corresponding cell. In this case, the radio network controller 120 may independently determine a power value control entity for each cell controlled by the base stations connected thereto.

However, the present invention is not limited to the embodiment of FIG. 8. According to an embodiment of the present invention, the radio network controller 120 may determine the power value control subject for the HSDPA channel in the cell that each base station takes into account in consideration of the OVSF code occupancy transmitted from the various base stations.

For example, in the mobile communication system 100 shown in FIG. 1, if the first OVSF code occupancy rate transmitted from the first base station 110-1 is not greater than the first threshold, the wireless network controller 120 may perform a first operation. The base station 110-1 determines the power value control entity for the HSDPA channel of the first cell, which is controlled by the first base station 110-1, and the first OVSF code occupancy is greater than the second threshold (the first threshold). If greater than), the wireless network controller 120 may determine the power value control entity for the HSDPA channel of the first cell as the wireless network controller 120 itself.

However, if the first OVSF code occupancy is greater than the first threshold but not greater than the second threshold, the radio network controller 120 is transmitted from the second base station 110-2 that controls the second cell adjacent to the first cell. The power value control entity for the HSDPA channel of the first cell may be determined according to the second OVSF code occupancy rate. If the second OVSF code occupancy is not greater than or greater than the second threshold, the wireless network controller 120 may determine the power value controlling entity for the HSDPA channel of the first cell as the wireless network controller 120 itself. However, if the second OVSF code occupancy is not greater than the second threshold, the wireless network controller 120 may determine the power value control entity for the HSDPA channel of the first cell as the first base station 110-1. Accordingly, when the first OVSF code occupancy is greater than the first threshold and the power value controlling entity is determined as the wireless network controller 120, when the first OVSF code occupancy approaches the first threshold, the wireless network controller 110 By increasing the power value without considering the situation of the adjacent cell (second cell), it is possible to reduce the possibility of interference between the first cell and the second cell.

In the above description, the power value control entity for the HSDPA channel according to the OVSF code occupancy is individually determined for each cell, but the present invention is not limited thereto. According to an embodiment of the present invention, the radio network controller 120 may collectively determine a power value control entity for the HSDPA channel for all cells of the radio access network 10. For example, when the total sum of the OVSF code occupancy rates of each cell constituting the radio access network 10 is less than the threshold, or when the cell whose OVSF code occupancy is less than the threshold is more than a certain ratio, the radio network controller 120 is wireless. Power value control entities for HSDPA channels of all cells in the access network 10 may be determined as the base stations 110-1, 110-2, and 110-3, respectively. In addition, if the total sum of the OVSF code occupancy of each cell constituting the radio access network 10 is greater than or equal to the threshold, or if the cell whose OVSF code occupancy is smaller than the threshold is smaller than a certain ratio, the radio network controller 120 may determine the HSDPA of each cell. The power value control entity for the channel may be determined by the radio network controller 120 itself.

In addition, there may be various embodiments that dynamically determine the power value control subject for the HSDPA channel according to the OVSF code occupancy in each cell, which should be construed as being within the scope of the present invention.

When the power value control entity is determined, an operation of allocating power of the HSDPA channel may be performed. If the power value controlling entity is the wireless network controller 120, the base station 110 may allocate power to the HSDPA channel according to the power value determined by the wireless network controller 120. However, if the power value control entity is the base station 110, the base station 110 determines the power value to be allocated to the HSDPA channel.

The power value to be allocated to the HSDPA channel may be determined according to the OVSF code occupancy. Preferably, the higher the OVSF code occupancy, the lower the power value to be allocated to the HSDPA channel, and the lower the OVSF code occupancy, the higher the power value to be allocated to the HSDPA channel. The information on the power value to be allocated to the HSDPA channel according to the OVSF code occupancy may be set in the base station 110 and the wireless network controller 120 to a value that can efficiently use radio resources through a preliminary experiment.

Meanwhile, the process of controlling the power value according to the OVSF code occupancy is similar to the process of controlling the power value according to the traffic channel occupancy described with reference to FIGS. 4 and 5, and thus a detailed description thereof will be omitted.

In addition, when the base station 110 determines the power value to be allocated to the HSDPA channel, the base station 110 may use the OVSF code occupancy in the cell it has jurisdiction, the radio network controller 120 is assigned to the HSDPA channel In determining the power value to be used, the wireless network controller 120 may use not only the OVSF code occupancy rate in a specific cell but also the OVSF code occupancy rate in a neighboring cell. The description of 120 is similar to that of the wireless network controller 120 using the traffic channel occupancy rate in the neighboring cell, and thus a detailed description thereof will be omitted.

In the above description, the power value to be allocated to the HSDPA channel of each cell is controlled by using the traffic channel occupancy or the OVSF code occupancy separately. However, in the mobile communication system 100 according to the embodiment of the present invention, the traffic channel occupancy and the OVSF code are controlled. The power value control entity is determined according to the combination of code occupancy, and the power value to be allocated to the HSDPA channel may be controlled.

For example, the sum of the traffic channel occupancy and the OVSF code occupancy may be compared with a predetermined threshold, or the sum of the traffic channel occupancy and the OVSF code occupancy, respectively given a specific weight, may be compared with the threshold to determine a power value control entity, and the HSDPA channel may be determined. The increase / decrease of the power value to be assigned may be determined.

The threshold value according to the embodiment of the present invention is a value that can be set by the mobile communication system administrator, and the mobile communication system administrator can arbitrarily change the threshold value according to the operation direction of the mobile communication system. Here, the threshold may be an integer or a decimal fraction, may have a negative or positive value, and if it has a negative value, its absolute value may be used to determine the power value controlling entity. It may be.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. You will understand that. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

1 is a diagram illustrating a mobile communication system according to an embodiment of the present invention.

2 is a flowchart illustrating a HSDPA call setup process according to an embodiment of the present invention.

3 is a flowchart illustrating a process of determining a power value control subject of an HSDPA channel according to an embodiment of the present invention.

4 is a flowchart illustrating a power allocation process according to an embodiment of the present invention.

5 is a flowchart illustrating a power allocation process according to another embodiment of the present invention.

6 is a diagram illustrating whether the OVSF code is occupied according to an embodiment of the present invention.

FIG. 7 is a diagram illustrating whether to assign an OVSF code to HSDPA only according to an embodiment of the present invention. FIG.

8 is a flowchart illustrating a process of determining a power value control subject of an HSDPA channel according to another embodiment of the present invention.

<Description of Symbols Regarding Main Parts of the Drawing>

10: wireless access 20: core network

110-1, 110-2, 110-3: base station 120: wireless network controller

130: terminal

Claims (20)

Measuring a load factor of the cell; Determining one of a base station and a wireless network controller as a power value controlling entity according to the measured load ratio; And Allocating power to a fast downlink packet access channel of the cell using a power value provided by the power value control entity; The load rate comprises at least one of a traffic channel occupancy rate and an orthogonal variable spreading element code occupancy rate of the cell, The traffic channel occupancy ratio is a ratio of the power allocated to a channel other than the fast downlink packet access channel among the channels used in the cell to the maximum power that the base station can support. The method of claim 1, The power value is provided from the radio network controller when the load rate is greater than a threshold, and the power value is provided from the base station when the load rate is below the threshold. delete delete The method of claim 1, And the orthogonal variable spreading element code occupancy ratio is a ratio of orthogonal variable spreading element codes occupied by a terminal among orthogonal variable spreading element codes allocated to channels other than the fast downlink packet access channel. The method of claim 5, The orthogonal variable spreading element code is an orthogonal variable spreading element code included in a predetermined spreading element layer. The method of claim 1, The orthogonal variable spreading element code occupancy ratio is a ratio of an orthogonal variable spreading element code occupied by a terminal among the orthogonal variable spreading element codes included in a predetermined spreading element layer. The method of claim 1, wherein the assigning step: Determining a power value control entity for the high speed downlink packet access channel as either the base station or the radio network controller according to the load ratio; And Allocating power to the fast downlink packet access channel according to the determined power value provided by the determined power value controlling entity. The method of claim 1, And the power value decreases with an increase in the load rate and increases with a decrease in the load rate. The method of claim 1, And the wireless network controller determines a power value to be allocated to the fast downlink packet access channel according to the load rate and the load rate of another cell adjacent to the cell. A wireless network controller for determining a power value control entity for a high speed downlink packet access channel of the cell according to a cell load ratio; And A base station for allocating power to the fast downlink packet access channel according to the power value determined by the power value control entity determined by the wireless network controller; The load rate includes at least one of a traffic channel occupancy rate and an orthogonal variable spreading factor code occupancy rate of the cell, The traffic channel occupancy ratio is a ratio of power allocated to a channel other than the fast downlink packet access channel to the maximum power that the base station can support among the channels used in the cell. The method of claim 11, The power value is provided from the radio network controller when the load rate is greater than a threshold, and the power value is provided from the base station when the load rate is below the threshold. delete delete The method of claim 11, And the orthogonal variable spreading element code occupancy ratio is a ratio of orthogonal variable spreading element codes occupied by a terminal among the orthogonal variable spreading element codes allocated to channels other than the fast downlink packet access channel. The method of claim 15, The orthogonal variable spreading element code is an orthogonal variable spreading element code included in a preset spreading element layer. The method of claim 11, The orthogonal variable spreading element code occupancy rate is a ratio of an orthogonal variable spreading element code occupied by a terminal among the orthogonal variable spreading element codes included in a preset spreading element layer. The method of claim 11, The base station measures the load factor, and the wireless network controller determines a power value control entity to provide the power value in accordance with the measured load factor. The method of claim 11, And the power value decreases with an increase in the load rate and increases with a decrease in the load rate. The method of claim 11, And the wireless network controller determines a power value to allocate to the fast downlink packet access channel according to the load rate and the load rate of another cell adjacent to the cell.

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