JP5205294B2 - Wireless communication control system and wireless communication control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently control the transmission power of a shared control channel (HS-SCCH) even when the transmission timing of the shared control channel is deviated from the transmission timing of a shared packet channel (HS-PDSCH). <P>SOLUTION: The radio communication control system 10, which controls transmission power of a shared control channel (HS-SCCH) for transmitting a control signal to a plurality of mobile stations UE, includes a transmission power control unit for controlling transmission power of the shared control channel (HS-SCCH) based on transmission power of an individual channel (A-DPCH), accompanying the shared control channel (HS-SCCH) and communication quality of the shared control channel (HS-SCCH); and a maximum transmission power control unit for controlling the maximum transmission power of the shared control channel (HS-SCCH) during a predetermined period of time. The transmission power control unit controls the transmission power of the shared control channel (HS-SCCH) so that the maximum transmission power is not exceeded. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a radio communication control system and a radio communication control method for controlling transmission power of a shared control channel that transmits control signals to a plurality of mobile stations.

  In recent years, as the above-described wireless communication control system, IMT-2000 (International Mobile Telecommunications-2000) is a higher-speed downlink packet transmission method, which has a higher peak transmission rate, lower transmission delay, higher throughput, etc. The intended “High Speed Downlink Packet Access (HSDPA) method” has been studied (for example, see Non-Patent Document 1).

  The HSDPA method is a transmission method in which one physical channel is shared by a plurality of mobile stations in time division and communicates, and the channel is assigned to a mobile station with better radio quality instantaneously, so the throughput of the entire system Can be improved.

  As described above, in order to perform communication by sharing a single physical channel among a plurality of mobile stations, which mobile station communicates using the physical channel in each TTI (Transmission Time Interval). However, in the HSDPA method, the above-mentioned notification is made to a plurality of mobile stations using a shared control channel called HS-SCCH (High Speed-Shared Control Channel).

  In the conventional HSDPA scheme, a value obtained by applying an offset to the transmission power of a dedicated channel (A-DPCH: Associated-Dedicated Physical Channel) associated with the HS-SCCH as the transmission power assigned to the HS-SCCH by the radio base station apparatus Transmission power control was performed by setting.

  Further, in the conventional HSDPA scheme, the radio base station apparatus sometimes sets an upper limit (maximum transmission power) of the transmission power of the HS-SCCH so that the transmission power is not excessively allocated to the HS-SCCH. .

“3rd Generation Partnership Project”, [online], Internet <URL: www.3gpp.org>

  However, in the conventional HSDPA scheme, the mobile station has a low moving speed and a high moving speed due to a difference in interleaving effect due to a large difference in TTI length between the HS-SCCH and the dedicated channel A-DPCH associated with the HS-SCCH. Thus, there is a problem that it is difficult to perform appropriate transmission power control with the same offset value.

  Further, in the conventional HSDPA scheme, when setting the upper limit value of the transmission power of the HS-SCCH so that the transmission power is not excessively allocated to the HS-SCCH, the transmission timing of the HS-SCCH and the HS-PDSCH (High Speed) are set. There is a problem in that it is difficult to efficiently allocate transmission power to HS-SCCH and HS-PDSCH for each TTI because the transmission timing of (Physical Downlink Shared Channel) is shifted. Here, the HS-PDSCH is a physical channel used for transmission of HS-DSCH (High Speed-Downlink Shared Channel).

  This problem will be described in detail with reference to FIGS. FIG. 5 shows an example of a transmission power allocation method in the case where the HS-SCCH transmission timing and the HS-PDSCH transmission timing are the same in the conventional HSDPA scheme, and FIG. 6 shows the HS-SCCH transmission timing in the conventional HSDPA scheme. An example of a transmission power allocation method when the transmission timing of SCCH and the transmission timing of HS-PDSCH are shifted is shown.

  Here, the remaining transmission power obtained by subtracting the transmission power allocated to the non-HS-Channel from the maximum total transmission power of the radio base station apparatus can be allocated as the transmission power of the HS-SCCH and the transmission power of the HS-PDSCH.

  Further, in the conventional HSDPA scheme, the HS-SCCH transmission power is determined within a range not exceeding the above-mentioned remaining transmission power, and the power obtained by subtracting the HS-SCCH transmission power from the remaining transmission power is determined as HS-PDSCH. Assigned as the transmission power.

  In the conventional HSDPA scheme, the transmission power of the HS-SCCH is controlled by a predetermined algorithm, and the upper limit (maximum value) of the HS-SCCH transmission power is set so that the transmission power is not excessively allocated to the HS-SCCH. (Transmission power) may be set.

  In the example of FIG. 5, since the transmission timing of HS-SCCH and the transmission timing of HS-PDSCH coincide, when the transmission power of HS-SCCH is small, the transmission power of HS-PDSCH is set to a large value. However, when the transmission power of HS-SCCH is large, the radio base station apparatus can perform efficient transmission power allocation by setting the transmission power of HS-PDSCH to a small value.

  However, in the HSDPA system specification defined in 3GPP, the HS-SCCH transmission timing and the HS-PDSCH transmission timing are shifted by 2 slots as in the example of FIG. Therefore, it is difficult to perform efficient transmission power allocation as described above.

  That is, in the example of FIG. 6, the transmission power of the HS-SCCH and the transmission power of the HS-PDSCH in a predetermined TTI are affected by the transmission power of the HS-PDSCH and the transmission power of the HS-SCCH in the next TTI, respectively. As a result, it becomes difficult to allocate transmission power efficiently.

  Specifically, as shown in FIG. 6, the transmission power of HS-SCCH # 1 is affected by the transmission power of HS-PDSCH # 1, and the transmission power of HS-PDSCH # 1 is HS-SCCH # 2. The transmission power of HS-SCCH # 2 is affected by the transmission power of HS-PDSCH # 2. Therefore, in such a case, in order to perform transmission power allocation as shown in FIG. 5, it is necessary to determine transmission power in consideration of all future transmission power, which is difficult to realize.

  In order to solve this problem, as shown in FIG. 7, in the conventional HSDPA scheme, when the HS-SCCH transmission timing is different from the HS-PDSCH transmission timing, the upper limit value of HS-SCCH (maximum A method for securing the transmission power of HS-SCCH fixedly by defining (transmission power) is considered.

  However, in this case, there is a problem that the efficiency of using the transmission power is deteriorated as compared with the transmission power allocation method in FIG. That is, in such a case, it is necessary to secure a certain amount of transmission power for the HS-SCCH. As a result, the transmission power allocated to the HS-PDSCH is reduced, so that the throughput of the system and the user is lowered.

  The present invention has been made in view of the above points. Transmission timing of a shared control channel (HS-SCCH) for transmitting a control signal to a plurality of mobile stations and packet data to the plurality of mobile stations are transmitted. To provide a wireless communication control system and a wireless communication control method for efficiently controlling the transmission power of the shared control channel even when the transmission timing of the shared packet channel (HS-PDSCH) is shifted Objective.

  A first feature of the present invention is a radio communication control system that controls transmission power of a shared control channel (HS-SCCH) that transmits a control signal to a plurality of mobile stations, the shared control channel (HS-SCCH). ) And the transmission power control unit for controlling the transmission power of the shared control channel (HS-SCCH) based on the transmission power of the dedicated channel (A-DPCH) and the communication quality of the shared control channel (HS-SCCH) It is a summary to comprise.

  According to this invention, it becomes possible to set the transmission power of an appropriate shared control channel based on the communication quality of the shared control channel, that is, the propagation environment, and it is necessary to secure extra transmission power in the shared control channel. As a result, the transmission power of the shared packet channel can be secured by that much, and the throughput of the system and the user can be improved.

  Further, according to this invention, when the transmission power of the shared packet channel is left as it is while setting the transmission power of the appropriate shared control channel, the total transmission power in the cell managed by the wireless communication control system is reduced. Since it becomes possible to reduce, the interference electric power to other cells can be reduced.

  In the first feature of the present invention, the transmission power control unit sets the transmission power of the shared control channel (HS-SCCH) by applying an offset to the transmission power of the dedicated channel (A-DPCH), and performs shared control. It is preferable to control the offset value according to the communication quality of the channel (HS-SCCH).

In the first feature of the present invention, the transmission power control unit uses the block error rate of the shared control channel (HS-SCCH) as the communication quality of the shared control channel (HS-SCCH), and performs shared control. It is preferable to control the offset value so that the block error rate of the channel (HS-SCCH) becomes the target value BLER _target .

  According to this invention, by controlling the offset value in an outer loop based on the block error rate of the shared control channel (HS-SCCH), the transmission power of the more appropriate and efficient shared control channel (HS-SCCH) Can be controlled.

In the first feature of the present invention, a shared packet channel (HS-DSCH) for transmitting packet data to a plurality of mobile stations is transmitted following the shared control channel (HS-SCCH). When the power control unit uses feedback information in the retransmission control (ARQ) of the shared packet channel (HS-DSCH) as the communication quality of the shared control channel (HS-SCCH) and receives the feedback information, the offset It is preferable to control so as to decrease the value of the offset and to increase the offset value when feedback information is not received.

  According to this invention, it is possible to control the transmission power of a more appropriate and efficient shared control channel (HS-SCCH) by controlling the offset value in an outer loop based on feedback information of retransmission control.

  Further, in the first feature of the present invention, following the shared control channel (HS-SCCH), a shared packet channel (HS-DSCH) for transmitting packet data to the plurality of mobile stations is transmitted. It is preferable that the transmission power control unit further controls the offset value based on a service type of the shared packet channel (HS-DSCH).

  According to this invention, when providing a service with low durability against transmission delay such as an IP telephone service or a streaming service, the offset value is set to a large value, and a transmission delay such as an FTP service or an e-mail service is provided. When providing a service with high durability against the above, by setting the offset value to be small, it is possible to provide a communication service according to QoS (Quality of Service).

  In the first feature of the present invention, a maximum transmission power control unit that controls the maximum transmission power of the shared control channel (HS-SCCH) in a predetermined period is provided, and the transmission power control unit exceeds the maximum transmission power. It is preferable to control the transmission power of the shared control channel (HS-SCCH) so that it does not occur.

  According to this invention, since it is possible to set the maximum transmission power of the optimum shared control channel (HS-SCCH) according to the situation at the time, the extra transmission power is set to the shared control channel (HS-SCCH). Therefore, it is possible to secure a larger amount of transmission power for the shared packet channel (HS-DSCH), and to improve the throughput of the system and the user.

  In the first aspect of the present invention, it is preferable that the maximum transmission power control unit controls the maximum transmission power based on a statistical value of transmission power of the shared control channel (HS-SCCH).

  According to this invention, the shared control channel is more appropriately and efficiently controlled by controlling the maximum transmission power of the shared control channel (HS-SCCH) based on the statistical value of the transmission power of the shared control channel (HS-SCCH). The transmission power of (HS-SCCH) can be controlled.

  In the first feature of the present invention, it is preferable that the maximum transmission power control unit controls the maximum transmission power so as not to exceed an upper limit value provided for each shared control channel (HS-SCCH).

  A second feature of the present invention is a radio communication control method for controlling transmission power of a shared control channel (HS-SCCH) for transmitting a control signal to a plurality of mobile stations, the shared control channel (HS-SCCH). ) To control the transmission power of the shared control channel (HS-SCCH) based on the transmission power of the dedicated channel (A-DPCH) and the communication quality of the shared control channel (HS-SCCH). Is the gist.

  In the second aspect of the present invention, the method further comprises a step B of controlling a maximum transmission power of the shared control channel in a predetermined period, and transmitting the shared control channel in the step A so as not to exceed the maximum transmission power. It is preferable to control the power.

  As described above, according to the present invention, the transmission timing of the shared control channel (HS-SCCH) for transmitting the control signal to the plurality of mobile stations UE and the sharing for transmitting the packet data to the plurality of mobile stations UE. Even when the transmission timing of the packet channel (HS-PDSCH) is deviated, it is possible to provide a wireless communication control system and a wireless communication control method for efficiently controlling the transmission power of the shared control channel.

1 is an overall configuration diagram of a wireless communication control system according to an embodiment of the present invention. It is a functional block diagram of the radio | wireless communication control system which concerns on one Embodiment of this invention. It is a figure which shows an example of the control method of the transmission power of the shared control channel in the radio | wireless communication control system which concerns on one Embodiment of this invention. It is a flowchart which shows the mobile communication control method which concerns on one Embodiment of this invention. It is a figure which shows an example of the control method of the transmission power of the shared control channel in the radio | wireless communication control system which concerns on a prior art. It is a figure which shows an example of the control method of the transmission power of the shared control channel in the radio | wireless communication control system which concerns on a prior art. It is a figure which shows an example of the control method of the transmission power of the shared control channel in the radio | wireless communication control system which concerns on a prior art.

(Configuration of wireless communication control system according to first embodiment of the present invention)
The configuration of the wireless communication control system according to the first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows an overall configuration diagram of a wireless communication control system according to the present embodiment. As shown in FIG. 1, the radio communication control system according to the present embodiment manages a radio base station apparatus BS that is radio-connected to a plurality of mobile stations UE # 1 to # 4, and the radio base station apparatus BS. It is comprised by the radio | wireless control apparatus RNC.

  In the present embodiment, a case where a radio communication control system is configured by the radio base station apparatus BS and the radio control apparatus RNC will be described, but the present invention is not limited to such a case, and the radio base station The present invention can also be applied to a case where a radio communication control system is configured only by the device BS, or a case where a radio communication control system is configured only from the radio control device RNC.

  Further, the radio communication control system according to the present embodiment transmits control signals to a plurality of mobile stations UE # 1 to # 4 when the HSDPA scheme is applied in the IMT-2000 system using the W-CDMA scheme. The transmission power of the shared control channel (hereinafter referred to as HS-SCCH) to be transmitted is controlled.

  Here, the mobile stations UE # 1 to # 4 are mobile stations that perform radio communication with the radio base station apparatus BS using the HSDPA scheme. Each of the mobile stations UE # 1 to # 4 uses an uplink and a dedicated channel associated with the HS-SCCH ( Hereinafter, a transmission power control command (TPC command) for transmission power control of (A-DPCH) is reported to the radio base station apparatus BS.

  As shown in FIG. 2, the wireless communication control system according to the present embodiment includes a plurality of A-DPCH transmission power control units (A-DPCH Power Controllers) 11 # 1 to 11 # 4, a switch 12, and a determination unit 13. HS-SCCH instantaneous transmission power control unit (HS-SCCH Inst Power Controller) 14, statistical calculation unit (Statistics Calculator) 15, HS-SCCH short interval maximum transmission power control unit (HS-SCCH Temporary Max Power Controller) 16 and a limiting unit (Power Limiter) 17.

  The A-DPCH transmission power control units 11 # 1 to 11 # 4 are provided for the mobile stations UE # 1 to # 4, and are transmitted from the mobile stations UE # 1 to # 4. The transmission power control of the A-DPCH of each of the mobile stations UE # 1 to # 4 is performed using the transmission power control command.

  The switch 12 transmits the A-DPCH transmission power of the mobile station UE scheduled to allocate the HS-SCCH to the HS-SCCH instantaneous transmission power control unit 14 together with the identification information of the mobile station UE for each TTI. To do.

  The determination unit 13 determines the communication quality (communication status) of the HS-SCCH, and transmits the determination result to the HS-SCCH instantaneous transmission power control unit 14.

  For example, the determination unit 13 determines whether the HS-SCCH block error rate exceeds a predetermined value as the HS-SCCH communication quality (communication status). Further, the determination unit 13 determines whether the feedback information in the retransmission control (HARQ) of the shared packet channel (hereinafter, HS-DSCH) is “Ack” from HS-DPCCH (High Speed-Dedicated Physical Control Channel). Or “DTX” may be determined as HS-SCCH communication quality (communication status).

  The HS-SCCH instantaneous transmission power control unit 14 transmits the HS-SCCH transmission power (HS in a predetermined TTI) based on the transmission power of the A-DPCH attached to the HS-SCCH and the communication quality of the HS-SCCH. -SCCH instantaneous transmission power) is controlled.

  Specifically, the HS-SCCH instantaneous transmission power control unit 14 transmits the identification information of the mobile station UE to which the HS-SCCH is allocated in the TTI transmitted from the switch 12 and the transmission power of the A-DPCH and the determination unit 13. The determination result is used to determine HS-SCCH transmission power (HS-SCCH instantaneous transmission power) satisfying a desired HS-SCCH block error rate by a predetermined instantaneous transmission power control algorithm. The HS-SCCH instantaneous transmission power control unit 14 transmits the determined HS-SCCH transmission power (HS-SCCH instantaneous transmission power) to the restriction unit 17.

  The HS-SCCH instantaneous transmission power control unit 14 uses, as the HS-SCCH communication quality, the transmission power of the HS-SCCH using the feedback information determination result in HARQ corresponding to the HS-DSCH transmitted to the mobile station UE # i. The example of the 1st algorithm for instantaneous transmission power control which controls (HS-SCCH instantaneous transmission power) is shown.

  The HS-SCCH instantaneous transmission power control unit 14 sets the HS-SCCH transmission power (HS-SCCH instantaneous transmission power) by offsetting the transmission power of the A-DPCH, and the HS-SCCH communication quality. The offset value is controlled according to

Specifically, when the HS-SCCH is assigned to the mobile station UE # i in a certain TTI, the HS-SCCH instantaneous transmission power control unit 14 determines the offset value Δ _i of the mobile station UE # _i and the mobile station UE The HS-SCCH transmission power (HS-SCCH instantaneous transmission power) P _HS-SCCH is calculated by the following equation using #i A-DPCH transmission power _PA-DPCHi .

P _HS-SCCH = P _A-DPCHj + Δ _i
Further, HS-SCCH instantaneous transmission power control unit 14 uses the determination result of the feedback information in HARQ corresponding to transmitted to the mobile station UE # i HS-DSCH, the offset value delta _i of the mobile station UE # i, Adjust according to the following formula. The determination result is transmitted from the determination unit 13.

When the determination result is “Ack”, Δ _i = Δ _i −Δ _adj × BLER _target
When the determination result is “Nack”, Δ _i = Δ _i −Δ _adj × BLER _target
When the determination result is “DTX”, Δ _i = Δ _i + Δ _adj × (1−BLER _target )
However, BLER _target is the target error rate of HS-SCCH, and _Δadj is the step width of the offset to be adjusted.

  “Ack” indicates “HS-DSCH communication OK”, “Nack” indicates “HS-DSCH communication NG”, and “DTX” indicates “no feedback information”.

  As shown in the above equation, the HS-SCCH instantaneous transmission power control unit 14 has received feedback information in the case where the determination results are “Ack” and “Nack”, that is, HS-SCCH retransmission control (HARQ). In this case, since the HS-SCCH communication for performing the HS-DSCH signaling is “OK”, the offset value is controlled to be lowered.

  On the other hand, if the HS-SCCH instantaneous transmission power control unit 14 does not receive feedback information in the case where the determination result is “DTX”, that is, feedback information in HS-DSCH retransmission control (HARQ), the HS-SCCH instantaneous transmission power control unit 14 Since the HS-SCCH communication for signaling is “NG”, control is performed to increase the offset value.

  Further, the HS-SCCH instantaneous transmission power control unit 14 controls the HS-SCCH transmission power (HS-SCCH instantaneous transmission power) by using the HS-SCCH block error rate as the HS-SCCH communication quality. 2 shows an example of an instantaneous transmission power control algorithm 2.

The second instantaneous transmission power control algorithm is different from the first instantaneous transmission power control algorithm in that the offset value Δ _i is adjusted by the HS-SCCH instantaneous transmission power control unit 14. Here, the HS-SCCH instantaneous transmission power control unit 14 adjusts the offset value Δ _i so that the HS-SCCH block error rate becomes the target value BLER _target by the following equation.

When the determination result is “the block error rate in HS-SCCH is below a predetermined value”,
Δ _i = Δ _i −Δ _adj
When the determination result is “the block error rate in HS-SCCH exceeds a predetermined value”,
Δ _i = Δ _i + Δ _adj
As shown in the above equation, the HS-SCCH instantaneous transmission power control unit 14 performs control so as to decrease the offset value when the determination result is “the block error rate of the HS-SCCH is below a predetermined value”.

  On the other hand, the HS-SCCH instantaneous transmission power control unit 14 performs control to increase the offset value when the determination result is “the block error rate of HS-SCCH exceeds a predetermined value”.

Further, the second instantaneous transmission power control algorithm may adjust the offset value Δ _i by the following equation instead of adjusting the offset value Δ _i by the above equation.

When the determination result is “no block error in HS-SCCH”,
Δ _i = Δ _i −Δ _adj × BLER _target
When the determination result is “block error in HS-SCCH”,
Δ _i = Δ _i + Δ _adj × (1−BLER _target )
Further, the HS-SCCH instantaneous transmission power control unit 14 may control the offset value according to the service type of the HS-DSCH signaled on the HS-SCCH.

Here, the HS-SCCH instantaneous transmission power control unit 14 controls the offset value Δ _i by the following equation using the offset value Δ _service depending on the service type of the HS-DSCH.

When the determination result is “Ack”, Δ _i = Δ _i −Δ _adj × BLER _target + Δ _service
When the determination result is “Nack”, Δ _i = Δ _i −Δ _adj × BLER _target + Δ _service
When the determination result is “DTX”, Δ _i = Δ _i + Δ _adj × (1−BLER _target ) + Δ _service
Or
When the determination result is “no block error in HS-SCCH”,
Δ _i = Δ _i −Δ _adj × BLER _target + Δ _service
When the determination result is “block error in HS-SCCH”,
Δ _i = Δ _i + Δ _adj × (1−BLER _target ) + Δ _service
The HS-SCCH instantaneous transmission power control unit 14 may control the offset value Δ _service depending on the service type according to the service type.

For example, the HS-SCCH instantaneous transmission power control unit 14 reduces the delay due to the HS-SCCH error when performing a service in which a delay due to an error is not desirable, such as IP telephone or streaming, by the HSDPA method. In order to do this, the offset value Δ _service can be set larger. On the other hand, the HS-SCCH instantaneous transmission power control unit 14 sets the offset value Δ _service when performing a service in which delay due to an error does not greatly affect the quality of service, such as FTP or e-mail transmission / reception, by HSDPA. You may set small. As a result, a communication system according to QoS can be provided.

  Note that when there are a plurality of HS-SCCHs, the HS-SCCH instantaneous transmission power control unit 14 performs the above-described process for each HS-SCCH.

  Further, the offset value control method is not limited to the above-described algorithm, and may be another Outer Loop algorithm as long as it satisfies the desired HS-SCCH communication quality.

  The statistical calculation unit 15 calculates a statistical value of transmission power per HS-SCCH transmitted in a predetermined period, for example, an average value and a variance value, using a predetermined algorithm, and the calculation result is calculated as HS-SCCH. It transmits to the short interval maximum transmission power control part 16.

  The HS-SCCH short interval maximum transmission power control unit 16 uses a predetermined short interval maximum transmission power control algorithm based on the HS-SCCH transmission power statistical value transmitted from the statistical calculation unit 15 for a predetermined period. The maximum transmission power per HS-SCCH (hereinafter referred to as HS-SCCH short section maximum transmission power) is set, and the set HS-SCCH short section maximum transmission power is transmitted to the restriction unit 17.

Here, an example of the above-described algorithm for controlling the maximum short-term transmission power will be shown. The HS-SCCH short interval maximum transmission power control unit 16 calculates or updates the short interval maximum transmission power P _{HS-SCCH, temporary max} per HS-SCCH by the following equation.

P _{HS-SCCH, temporary max} = α × MEAN _HS-SCCH + β × √Variance _HS-SCCH
Where α and β are parameter coefficients. MEAN _HS-SCCH is an average value of transmission power per _HS-SCCH transmitted from the statistical calculation unit 15, and Variance _HS-SCCH is an average value per _HS-SCCH transmitted from the statistical calculation unit 15. This is a dispersion value of the transmission power of the transmission power, and is calculated as follows.

MEAN _HS-SCCH = (1-τ) × P _HS-SCCH + τ × MEAN _HS-SCCH
Variance _HS-SCCH = (1−τ) × (P _HS-SCCH− MEAN _HS-SCCH ) ² + τ × Variance _HS-SCCH
However, τ is a parameter for determining a predetermined section for obtaining an average value.

Statistical processing of the above average value MEAN _HS-SCCH and variance value Variance _HS-SCCH is performed for all HS-SCCH transmitted to the mobile station UE, and there is no mobile station UE to be allocated and transmission is performed. The HS-SCCH that has not been performed is not subjected to the statistical processing of the average value MEAN _HS-SCCH and the variance value Variance _HS-SCCH .

Further, the method for obtaining the above average value MEAN _HS-SCCH and variance value Variance _HS-SCCH is not limited to the above method, and the measurement interval may be obtained and calculated normally.

  Furthermore, in the present embodiment, the average value and the variance value are cited as the statistical values, but the statistical value according to the present invention is not limited to the average value and the variance value, and the transmission power of the HS-SCCH is estimated. Any other index may be used as long as it is a possible index.

Further, the HS-SCCH short interval maximum transmission power control unit 16 relates to the above-described HS-SCCH short interval maximum transmission power P _{HS-SCCH, temporary max} , and the maximum transmission power (per _HS-SCCH provided by the following equation) The upper limit value) P _{HS-SCCH, max} may be set to be limited.

When P _{HS-SCCH, temporary max} > P _{HS-SCCH, max} , P _{HS-SCCH, temporary max} = P _{HS-SCCH, max}
That is, the HS-SCCH short interval maximum transmission power control unit 16 sets the HS-SCCH short interval maximum transmission power P _{HS-SCCH, temporary} so as not to exceed the upper limit value P _{HS-SCCH, max} provided for each _{HS-SCCH. It} may be configured to control _max .

  The restricting unit 17 transmits the HS-SCCH transmission power (HS-SCCH instantaneous transmission power) for each TTI transmitted from the HS-SCCH instantaneous transmission power control unit 14 from the HS-SCCH short interval maximum transmission power control unit 16. HS-SCCH short interval maximum transmission power is set as an upper limit value. That is, the restriction unit 17 controls the HS-SCCH transmission power (HS-SCCH instantaneous transmission power) so as not to exceed the HS-SCCH short interval maximum transmission power.

  Specifically, when the HS-SCCH transmission power (HS-SCCH instantaneous transmission power) is larger than the HS-SCCH short section maximum transmission power, the limiting unit 17 sets the HS-SCCH short section maximum transmission power. Set as transmission power of HS-SCCH. On the other hand, when the HS-SCCH transmission power (HS-SCCH instantaneous transmission power) is smaller than the HS-SCCH short-term maximum transmission power, the limiting unit 17 transmits the HS-SCCH instantaneous transmission power to the HS-SCCH transmission. Set as power.

  That is, the restriction unit 17 can control the transmission power of the HS-SCCH so as not to exceed the maximum transmission power of the HS-SCCH short section.

  FIG. 3 shows an image diagram when the above-described short interval maximum transmission power control is performed.

That is, if it is determined from the past HS-SCCH transmission power statistics that the HS-SCCH transmission power is small, the HS-SCCH short interval maximum transmission power is set small, and the HS-SCCH transmission power is If it is determined that the transmission power is large, the HS-SCCH short interval maximum transmission power is set to be large, so that transmission power can be efficiently secured for the HS-PDSCH, and the throughput of the system and the user is increased.

  For example, when the number of mobile stations UE in the cell is large, the HS-DSCH is allocated only to the mobile stations UE having good communication quality due to the diversity effect of the mobile stations UE due to scheduling. The probability that the transmission power of the HS-SCCH that satisfies the error rate is small increases.

  That is, in such a case, the average value of the transmission power of HS-SCCH becomes small, and since the HS-SCCH is always assigned to the mobile station UE with good communication quality, the dispersion value of the transmission power of HS-SCCH also becomes small, As a result, the HS-SCCH short interval maximum transmission power decreases, and the transmission power allocated to the HS-DSCH increases accordingly.

  On the other hand, when the number of mobile stations UE in the cell is small, the HS-DSCH is allocated to various mobile stations UE from the mobile station UE having a good communication quality to the mobile station UE having a poor communication quality. The average value of the transmission power of HS-SCCH becomes larger than that of HS-SCCH, and the dispersion value of the transmission power of HS-SCCH also becomes larger. As a result, the HS-SCCH short interval maximum transmission power becomes larger.

  In this way, when the HS-SCCH short interval maximum transmission power is large, the HS-SCCH block error rate of the mobile station UE with poor communication quality is improved, so the service quality of the mobile station UE with poor communication quality is improved. It is effective in the sense of improving.

  In this case, if the transmission power of the HS-DSCH is not secured to a large extent and the transmission power of the HS-DSCH is left as it is, the total transmission power of the cell can be reduced. It becomes possible to reduce interference power.

  The configuration of the wireless communication control system according to the present embodiment may be a configuration that performs only the above-described instantaneous transmission power control, or may be a configuration that performs only the above-described short-term maximum transmission power control. . In the former case, the limiting unit 17 sets a limit on the transmission power of the HS-SCCH, with the maximum transmission power of the predetermined HS-SCCH as an upper limit value.

(Operation of the wireless communication control system according to the present embodiment)
With reference to FIG. 4, the operation of the wireless communication control system 10 according to the present embodiment will be described. FIG. 4 is a flowchart showing an example of an operation for performing HS-SCCH instantaneous transmission power control by the HSDPA method in the IMT-2000 system using the W-CDMA method.

  In step 1001, the HS-SCCH instantaneous transmission power control unit 14 determines an offset value based on the determination result transmitted from the determination unit 13. Here, examples of the determination result include the presence / absence of an HS-SCCH block error and feedback information in HS-DSCH HARQ.

  In step 1002, the HS-SCCH instantaneous transmission power control unit 14 uses the offset value described above and the transmission power of the A-DPCH of the mobile station UE to which the HS-SCCH is allocated in the TTI, to determine a predetermined HS-SCCH. HS-SCCH instantaneous transmission power is determined based on the instantaneous transmission power control algorithm.

  On the other hand, in step 1003, the statistical calculation unit 15 uses a predetermined short interval maximum transmission power control algorithm to calculate a statistical value of transmission power per HS-SCCH transmitted, for example, an average value or a variance value. calculate.

In step 1004, the HS-SCCH short interval maximum transmission power control unit 16 uses a predetermined short interval maximum transmission power control algorithm from the statistical value of the transmission power of the HS-SCCH transmitted from the statistical calculation unit 15, The short section maximum transmission power per HS-SCCH is determined.

  In Step 1005, the control unit 17 relates to the HS-SCCH instantaneous transmission power transmitted from the HS-SCCH instantaneous transmission power control unit 14, and the HS-SCCH short interval transmitted from the HS-SCCH short interval maximum transmission power control unit 16. Limit the maximum transmission power as the upper limit.

  Note that the application range of the wireless communication control system and the wireless communication control method according to the present invention is not limited to the HSDPA method, which is a high-speed packet transmission system in the IMT-2000 system of the W-CDMA method, but of the CDMA-TDD method and the CDMA2000 method. This is also effective in a high-speed packet transmission system in the IMT-2000 system.

(Operations and effects of the wireless communication control system according to the present embodiment)
According to the radio communication control system according to the present embodiment, based on the communication quality of the shared control channel (HS-SCCH), that is, the propagation environment, the transmission power (HS-SCCH) of the appropriate shared control channel (HS-SCCH) Instantaneous transmission power) can be set, and it is not necessary to secure extra transmission power in the shared control channel (HS-SCCH), so that the transmission power of the shared packet channel (HS-DSCH) is increased accordingly. Can be ensured, and the throughput of the system and the user can be improved.

  Further, according to the radio communication control system according to the present embodiment, while setting the transmission power (HS-SCCH instantaneous transmission power) of the appropriate shared control channel (HS-SCCH), the shared packet channel (HS-DSCH) When the transmission power is left as it is, it becomes possible to reduce the total transmission power in the cell managed by the radio communication control system, and therefore it is possible to reduce the interference power to other cells.

  Also, according to the radio communication control system according to the present embodiment, more appropriate and efficient sharing control is achieved by controlling the offset value in an outer loop based on the block error rate of the shared control channel (HS-SCCH). The transmission power of the channel (HS-SCCH) can be controlled.

  Further, according to the radio communication control system according to the present embodiment, by controlling the offset value in an outer loop based on the feedback information of retransmission control, a more appropriate and efficient shared control channel (HS-SCCH) Transmission power can be controlled.

  In addition, according to the wireless communication control system according to the present embodiment, when providing a service with low durability against transmission delay, such as an IP telephone service or a streaming service, the offset value is set to be large, and an FTP service or electronic service is set. A communication service according to QoS (Quality of Service) can be provided by setting a small offset value when providing a service with high durability against transmission delay such as a mail service.

  In addition, according to the wireless communication control system according to the present embodiment, it is possible to set the maximum transmission power of the optimal shared control channel (HS-SCCH) according to the situation at the time, so extra transmission power Need to be reserved for the shared control channel (HS-SCCH), and it is possible to secure a larger amount of transmission power for the shared packet channel (HS-DSCH), thereby improving system and user throughput. It becomes possible to plan.

  Further, according to the radio communication control system according to the present embodiment, by controlling the maximum transmission power of the shared control channel (HS-SCCH) based on the statistical value of the transmission power of the shared control channel (HS-SCCH). Therefore, the transmission power of the shared control channel (HS-SCCH) can be controlled more appropriately and efficiently.

UE # 1, UE # 2, UE # 3, UE # 4 ... mobile station BS ... radio base station device RNC ... radio control device 10 ... radio communication control system 11 # 1, 11 # 4 ... A-DPCH transmission power control unit DESCRIPTION OF SYMBOLS 12 ... Switch 13 ... Determination part 14 ... HS-SCCH instantaneous transmission power control part 15 ... Statistical calculation part 16 ... HS-SCCH short interval maximum transmission power control part 17 ... Restriction part

Claims (7)

A wireless communication control system that controls transmission power of a shared control channel that transmits control signals to a plurality of mobile stations,
The sum of the transmission power of the shared control channel and the transmission power of the shared packet channel for transmitting packet data to the plurality of mobile stations is equal to or less than a predetermined transmission power,
The transmission timing of the shared control channel is different from the transmission timing of the shared packet channel,
A transmission power control unit for controlling the transmission power of the shared control channel based on the transmission power of the dedicated channel associated with the shared control channel and the communication quality of the shared control channel;
A maximum transmission power control unit for controlling the maximum transmission power of the shared control channel in a predetermined period,
The transmission power control unit controls the transmission power of the shared control channel so as not to exceed the maximum transmission power ;
The wireless communication control system, wherein the maximum transmission power control unit controls the maximum transmission power based on an average value or a dispersion value of transmission power per shared control channel transmitted in a predetermined period . The radio communication control system according to claim 1 , wherein the maximum transmission power control unit controls the maximum transmission power so as not to exceed an upper limit value provided for each shared control channel. The transmission power control unit sets transmission power per shared control channel by offsetting transmission power of the dedicated channel,
The radio communication control system according to claim 1 , wherein the transmission power control unit controls the value of the offset according to communication quality of the shared control channel. The transmission power control unit uses the block error rate of the shared control channel as the communication quality of the shared control channel,
The radio transmission control system according to claim 3 , wherein the transmission power control unit controls the offset value so that a block error rate of the shared control channel becomes a target value. The transmission power control unit uses feedback information in retransmission control of the shared packet channel as communication quality of the shared control channel,
The transmission power control unit performs control so as to decrease the offset value when the feedback information is received, and controls to increase the offset value when the feedback information is not received. The wireless communication control system according to claim 3 . The transmission power control unit is further based on the service type of the shared packet channel, a radio communication control system according to claim 4 or 5, characterized in that controlling the value of the offset. A wireless communication control method for controlling transmission power of a shared control channel for transmitting control signals to a plurality of mobile stations,
The sum of the transmission power of the shared control channel and the transmission power of the shared packet channel for transmitting packet data to the plurality of mobile stations is equal to or less than a predetermined transmission power,
The transmission timing of the shared control channel is different from the transmission timing of the shared packet channel,
Controlling the transmission power of the shared control channel based on the transmission power of the dedicated channel associated with the shared control channel and the communication quality of the shared control channel;
And B for controlling the maximum transmission power of the shared control channel in a predetermined period,
In the step A, the transmission power of the shared control channel is controlled so as not to exceed the maximum transmission power ,
In the step B, the maximum transmission power is controlled based on an average value or a dispersion value of transmission power per shared control channel transmitted in a predetermined period .

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