JP2004349883A - Wireless base station device - Google Patents

Abstract

A radio base station capable of reducing the probability of conflicting control information transmission requests between mobile stations while maintaining fairness in load between common control channels.
A wireless base station device according to the present invention is a wireless base station device that accommodates a plurality of mobile station devices and allocates a predetermined number of communication channels to each of the mobile station devices. Code allocation for allocating communication channels for the predetermined number selected based on the congestion degree (use rate, number of registered mobile stations, non-selection rate) of each communication channel when allocating communication channels to mobile station apparatuses to perform The unit 14 is provided.
[Selection] Figure 2

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a radio base station apparatus which is one of apparatuses constituting a radio communication system such as mobile communication, and particularly relates to an HSDPA (High-Speed Downlink Packet Access) for realizing high-speed packet data transmission. The present invention relates to a radio base station device to be employed.
[0002]
[Prior art]
Hereinafter, processing of a conventional wireless base station (hereinafter, referred to as a base station) and processing of a conventional wireless communication system including the base station will be described. The standardization work of HSDPA for the purpose of increasing the speed of downlink data transmission of W-CDMA (wideband-Code Division Multiple Access) is being performed in 3GPP (3rd Generation Partnership Project).
[0003]
HSDPA dynamically assigns a plurality of spreading codes assigned for a common data channel: HS-DSCH (High Speed Downlink Shared Channel) to a plurality of mobile stations: UE (User equipment) every 2 msec radio frame. This is a method of transmitting data by assigning the data. In addition, in order to realize high-speed data transmission, an adaptive modulation and coding (AMC) technique that adaptively changes a modulation scheme and a coding rate, and an HARQ (Hybrid Hybrid) that combines an ARQ (Automatic Repeat reQuest) technique and an error correction technique. (ARQ) technology.
[0004]
Also, in HSDPA, in order to notify each mobile station of a spreading code to be allocated for data transmission, or to operate AMC technology or HARQ technology, the base station which is the transmitting side is the receiving side. It is necessary to transmit control information together with user data to the mobile station. As a channel for transmitting this control information, a common control channel: HS-SCCH (Shared Control Channel for HS-DSCH) has been introduced.
[0005]
Here, a method of operating a common control channel in a conventional communication system will be described (see Non-Patent Document 1). For example, when focusing on one mobile station, the mobile station is instructed via the preceding common control channel which spreading code should be used to receive the common data channel.
[0006]
The base station can provide a plurality of common control channels, which are distinguished by different spreading codes for data transmission. Then, the plurality of common control channels are shared by a plurality of mobile stations. Further, a maximum of four common control channels are allocated to the mobile station. The mobile station receives all of them, and receives control information from one common control channel in which control information directed to the mobile station is placed. However, in the next successive frame, only the same common control channel needs to be received, and it is not necessary to receive all channels.
[0007]
[Non-patent document 1]
3GPP TS25.308 v5.2.0
[0008]
[Problems to be solved by the invention]
However, the conventional base station and wireless communication system have the following problems.
[0009]
For example, when a common control channel with a high degree of congestion is allocated to a newly accommodated mobile station, there is a high possibility that the common control channel will compete with a control information transmission request addressed to another mobile station, and control information cannot be transmitted. There is a problem that a state occurs.
[0010]
FIG. 15 is a diagram for specifically explaining the above problem. For example, the common control channels (1) and (2) are assigned to the mobile station (1), and the common control channels (1) and (2) are also assigned to the mobile station (2). It is assumed that the channel usage rate is biased as shown in the figure. In this state, if the base station further accommodates the mobile station (3) and allocates the channels (1) and (2) having a high usage rate as the common control channel, for example, the mobile station moves at a certain radio frame timing. If the common control channels (1) and (2) have already been selected to transmit control information destined for stations (1) and (2), a common control channel for transmitting control information destined for mobile station (3) The control channel cannot be selected.
[0011]
Further, the mobile station has a capability of simultaneously receiving a plurality of common control channels. However, for example, there is a problem that as the number of simultaneously received common control channels increases, power consumption in a receiving circuit increases. Was. On the other hand, when the number of simultaneously received common control channels is reduced, there is a high possibility that control information transmission requests addressed to mobile stations will compete with each other, causing a state where control information cannot be transmitted.
[0012]
Further, when the mobile station leaves the accommodated base station, there is a problem that the congestion degree between the common control channels is biased, and the fairness of the load between the common control channels cannot be maintained.
[0013]
Further, even when the average congestion degree of all common control channels is reduced due to the departure of a mobile station in a specific base station, the number of common control channels assigned to each mobile station is large. If so, there is a problem that the power consumption of the mobile station cannot be reduced. Further, even when the average congestion degree of all common control channels increases with the addition of mobile stations in a specific base station, the number of common control channels assigned to each mobile station is reduced. If so, there is a high possibility that a request for transmission of control information destined for each mobile station will conflict, and a state in which control information cannot be transmitted occurs.
[0014]
Also, in the processing of the base station, a common control channel for actually transmitting control information is selected from a plurality of common control channels assigned to a certain mobile station, for example, when a common control channel with high congestion is selected, the same There is a problem that the probability of conflict with a request for transmission of control information destined for another mobile station to which a common control channel is assigned increases, and as a result, a state occurs in which control information destined for another mobile station cannot be transmitted.
[0015]
FIG. 16 is a diagram for specifically explaining the above problem. Here, it is assumed that the usage rate of each common control channel is biased as shown in the figure. When the common control channel (2) having a high usage rate is selected from the common control channels (2) and (3) to which the mobile station (3) is assigned, the mobile station (1) or the mobile station (1) to which the same common control channel is assigned. The probability of competing with the request for transmission of control information addressed to (2) increases, resulting in a state where control information addressed to mobile station (1) or (2) cannot be transmitted.
[0016]
The present invention has been made in view of the above, and reduces power consumption of mobile stations and competes for transmission of control information between mobile stations while maintaining fairness of load between common control channels. It is an object of the present invention to obtain a wireless base station that realizes a reduction in probability.
[0017]
[Means for Solving the Problems]
In order to solve the above-mentioned problems and achieve the object, a wireless base station apparatus according to the present invention accommodates a plurality of mobile station apparatuses and has a predetermined number of communication channels for each of the mobile station apparatuses. A communication base station for allocating a communication channel to a newly accommodated mobile station apparatus, and allocating the predetermined number of communication channels selected based on the congestion degree of each communication channel. Means (corresponding to a spreading code allocating unit 14 in an embodiment described later).
[0018]
According to the present invention, for example, the load between the common control channels is equalized by preferentially assigning the common control channels with a low usage rate to the mobile stations. In addition, the possibility of conflicting transmission requests for control information addressed to each mobile station to which the same common control channel is allocated is reduced.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a radio base station apparatus (hereinafter, referred to as a base station) according to the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is not limited by the embodiment.
[0020]
Embodiment 1 FIG.
FIG. 1 is a diagram showing a basic configuration of a base station according to the present invention. The base station includes a radio channel control unit 1, a data buffer unit 2, a modulation / spreading processing unit 3, and an upper layer processing unit 4. Consists of
[0021]
The upper layer processing unit 4 instructs the wireless channel control unit 1 to additionally register a new mobile station and delete the registered mobile station, and receives common control channel allocation information from the wireless channel control unit 1. Further, the data buffer unit 2 accumulates transmission waiting data input to the base station and addressed to each mobile station, and notifies the radio channel control unit 1 of the buffer status. Then, the user data is read from the buffer in response to a read instruction from the wireless channel control unit 1. The radio channel control unit 1 allocates a common data channel spreading code and a common control channel spreading code to each mobile station for each radio frame based on the buffer status notified from the data buffer unit 2, and The section 2 is notified of an instruction to read user data. Then, it notifies the modulation / spreading processing unit 3 of the read user data and the internally generated control information. At this time, the spread code information corresponding to the user data and the control information is notified at the same time. Further, the modulation / spreading unit 3 modulates the received user data and control information, and spreads the result with the designated spreading code.
[0022]
FIG. 2 is a diagram showing a configuration of the first embodiment of the radio channel control unit 1, wherein a scheduling unit 11, a common control channel spreading code selecting unit 12, a spreading code table 13, a spreading code assignment It has a unit 14, a common control channel spreading code table 15, and a usage rate storage table 16. The spreading code table 13 stores a selectable common control channel spreading code assigned to each mobile station. In HSDPA, a maximum of four common control channel spreading codes can be assigned to one mobile station. Further, the common control channel spreading code table 15 stores common control channel spreading codes usable in the base station. The usage rate storage table 16 stores the usage rate of each common control channel representing one parameter of the congestion degree. As an example, the usage rate is “the number of used frames in the past N frames / N”. FIG. 3 is a diagram illustrating a configuration example of the usage rate storage table.
[0023]
Here, the operation of the base station according to the present embodiment will be described in detail with reference to the drawings. First, the scheduling unit 11 determines the type and number of common data channel spreading codes to be assigned to each mobile station based on the buffer status notified from the data buffer unit 2. Further, it performs a process of notifying the data buffer unit 2 of a read instruction, a process of generating control information for a mobile station, and a process of generating common data channel spreading code information for controlling the modulation / spreading unit 3. Further, it requests a common control channel spreading code selection unit 12 described later to select a common control channel spreading code.
[0024]
The common control channel spreading code selection unit 12 selects a common control channel spreading code to be assigned to each mobile station from the spreading code table 13, and outputs common control channel spreading code information for controlling the modulation / spreading processing unit 3. Generate. Further, the usage rate in the past N frames of each common control channel is stored in the usage rate storage table 16. Note that the value of the number of frames N for calculating the average usage rate may be a fixed value, or may be the number of frames from the time when the previous addition or deletion of the mobile station was completed to the present.
[0025]
The spreading code allocator 14 determines a common control channel spreading code to be allocated to the mobile station in response to the mobile station addition request, and sets the result in the spreading code table 13. Further, it generates common control channel allocation information to notify the mobile station of the determination result, and notifies the higher layer processing unit 4 of the generated information. In the allocation process, at least one spreading code is selected from the available common control channel spreading codes based on the usage rate of each common control channel stored in the usage rate storage table 16.
[0026]
Next, the operation of the spreading code allocating unit 14 which is a feature of the present embodiment will be described with reference to a flowchart. FIG. 4 is a flowchart showing the processing of the spreading code allocating unit 14.
[0027]
First, when allocating a common control channel to a new mobile station, the spreading code allocating unit 14 refers to the usage rate storage table 16 and selects a common control channel having the lowest usage rate from the stored common control channels. (Step S1). Then, a common control channel spreading code corresponding to the selected common control channel is set in the spreading code table 13 (step S2).
[0028]
After that, the spreading code allocating unit 14 repeatedly executes the processing of steps S1 and S2 over the number of allocations designated in advance (step S3). Finally, the spreading code allocating unit 14 generates common control channel allocation information that associates the mobile station with the allocated common control channel, and notifies the higher layer processing unit 4 of the generated information (step S4).
[0029]
For example, assuming the usage rate storage table 16 shown in FIG. 3 and allocating four common control channels to a newly added mobile station, the base station uses common control channels (6), (2), and (4). And (5).
[0030]
As described above, in the present embodiment, a common control channel with a low usage rate is preferentially assigned to a mobile station. This makes it possible to equalize the load between the common control channels. In addition, the possibility that control information transmission requests addressed to mobile stations to which the same common control channel is allocated conflicts is reduced, so that the possibility that control information can be transmitted is increased as compared with the related art.
[0031]
Embodiment 2 FIG.
In Embodiment 1 described above, “utilization rate” is used as a common control channel selection index, but in Embodiment 2, “registered mobile station number” is used as a common control channel selection index. Note that the same components as those of the first embodiment described above are denoted by the same reference numerals, and description thereof will be omitted. In this embodiment, a registered mobile station number storage table 17 is used instead of the usage rate storage table 16.
[0032]
FIG. 5 is a diagram illustrating a configuration example of a registered mobile station number storage table. In the present embodiment, the common control channel spreading code selection unit 12 stores the number of registered mobile stations of each common control channel representing one parameter of the congestion degree in the registered mobile station number storage table 17. Here, as an example, it is assumed that 8, 1, 4, 3, 7, and 5 mobile stations are assigned to the common control channels (1) to (6), respectively.
[0033]
Here, the operation of the spreading code allocating unit 14 which is a feature of the present embodiment will be described. In the present embodiment, only operations different from those of the first embodiment described above will be described.
[0034]
First, when allocating a common control channel to a new mobile station, the spreading code allocating unit 14 refers to the registered mobile station number storage table 17 and selects a common mobile station having the least number of registered mobile stations from the stored common control channels. Select a control channel. Then, the common control channel spreading code corresponding to the selected common control channel is set in the spreading code table 13.
[0035]
Thereafter, the spreading code allocating unit 14 repeatedly executes the above selection / setting processing over the number of allocations designated in advance. Finally, the spreading code allocating unit 14 generates common control channel allocation information that associates the mobile station with the allocated common control channel, and notifies the higher layer processing unit 4 of the generated information.
[0036]
For example, assuming the registered mobile station number storage table 17 shown in FIG. 5 and allocating four common control channels to a newly added mobile station, the base station uses the common control channels (2), (4), (4). 3) and (6) will be assigned.
[0037]
As described above, in the present embodiment, a common control channel with a small number of registered mobile stations is preferentially allocated to mobile stations. This makes it possible to equalize the load between the common control channels. In addition, since the possibility that the transmission request of the control information addressed to each mobile station to which the same control channel is allocated conflicts is reduced, the possibility that the control information can be transmitted is increased as compared with the related art.
[0038]
Embodiment 3 FIG.
In the above-described embodiment, “use rate” or “the number of registered mobile stations” is used as a common control channel selection index. However, in the third embodiment, “non-selection rate” is used as a common control channel selection index. Use Note that the same components as those of the first embodiment described above are denoted by the same reference numerals, and description thereof will be omitted. In the present embodiment, an unselectable rate storage table 18 is used instead of the usage rate storage table 16.
[0039]
FIG. 6 is a diagram illustrating a configuration example of the non-selectable rate storage table. In the present embodiment, the common control channel spreading code selection unit 12 stores the non-selection rate of each common control channel representing one parameter of the congestion degree in the non-selection rate storage table 18. Here, as an example, it is assumed that the unselectable rates of the common control channels (1) to (6) are 0.5, 0.2, 0.7, 0.3, 0.3, and 0.1. Note that the selection is not possible, which means that the common control channel spreading code selecting unit 12 attempts to select the common control channel spreading code from the spreading code table 13, but another mobile station has already selected the spreading code in the same radio frame. Means that it cannot be selected. The non-selection rate is “the number of non-selection times in past N frames / N”.
[0040]
Here, the operation of the spreading code allocating unit 14 which is a feature of the present embodiment will be described. In the present embodiment, only operations different from those of the first or second embodiment described above will be described.
[0041]
First, when allocating a common control channel to a new mobile station, the spreading code allocating unit 14 refers to the non-selection rate storage table 18 and selects a common control channel having the lowest non-selection rate from the stored common control channels. Select Then, the common control channel spreading code corresponding to the selected common control channel is set in the spreading code table 13.
[0042]
Thereafter, the spreading code allocating unit 14 repeatedly executes the above selection / setting processing over the number of allocations designated in advance. Finally, the spreading code allocating unit 14 generates common control channel allocation information that associates the mobile station with the allocated common control channel, and notifies the higher layer processing unit 4 of the generated information.
[0043]
For example, assuming the non-selection rate storage table 18 shown in FIG. 6 and allocating four common control channels to a newly added mobile station, the base station uses common control channels (6), (2), and (4). ) And (5).
[0044]
As described above, in the present embodiment, a common control channel having a low unselectable rate is preferentially assigned to a mobile station. This makes it possible to equalize the load between the common control channels. In addition, since the possibility that the transmission request of the control information addressed to each mobile station to which the same control channel is allocated conflicts is reduced, the possibility that the control information can be transmitted is increased as compared with the related art.
[0045]
Embodiment 4 FIG.
In the above first to third embodiments, the number of common control channels to be allocated to each base station is a fixed value. In the fourth embodiment, the number of common control channels is allocated to each mobile station using the average usage rate of all common control channels. Determine the number of common control channels.
[0046]
FIG. 7 is a diagram showing the configuration of the fourth embodiment of the radio channel control unit 1, and further includes an allocation number derivation table 21 in addition to the configuration of the first embodiment described above. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
[0047]
FIG. 8 is a diagram illustrating a configuration example of the allocation number derivation table. The allocation number derivation table 21 according to the present embodiment is a table for deriving the number allocated as a common control channel from the average usage rate, and stores the average usage rate and the number for each average usage rate range in association with each other. .
[0048]
Here, the operation of the spreading code allocating unit 14 which is a feature of the present embodiment will be described. FIG. 9 is a flowchart showing the processing of the spreading code allocating unit 14. In the present embodiment, only operations different from those of the first to third embodiments described above will be described.
[0049]
When allocating a common control channel to a new mobile station, the spreading code allocating unit 14 obtains an average usage rate of the common control channel using the usage rate storage table 16, and, based on the average usage rate, calculates the average number of common control channels from the allocation number derivation table 21. The number of common control channels to be allocated is derived (step S11). For example, when the average usage rate is 0.5, the number to be assigned is two. The number of common control channels to be allocated may be weighted according to the importance of the mobile station.
[0050]
Thereafter, the spreading code allocating unit 14 repeatedly executes the above-described predetermined selection / setting processing (corresponding to steps S1 and S2) for the number of allocations determined in step S11 (step S12).
[0051]
As described above, in the present embodiment, the number of common control channels to be allocated is derived based on the average usage rate of all common control channels. Accordingly, in addition to the effects of the first to third embodiments described above, a necessary and sufficient number of common control channels can be further allocated to the mobile station. In addition, since a necessary and sufficient number of common control channels can be allocated, it is possible to eliminate a reception operation for an unnecessary common control channel, and accordingly, it is possible to significantly suppress the power consumption of the mobile station. For the same reason, it is possible to further reduce the possibility that each mobile station to which the same control channel is assigned competes.
[0052]
Embodiment 5 FIG.
In the above-described fourth embodiment, “average usage rate” is used as an index for determining the number of common control channels to be allocated. However, in the fifth embodiment, “average usage rate” is used as a determination index for the number of common control channels to be allocated. Use. Note that the same components as those of the fourth embodiment described above are denoted by the same reference numerals, and description thereof will be omitted. In this embodiment, a registered mobile station number storage table 17 is used instead of the usage rate storage table 16.
[0053]
FIG. 10 is a diagram illustrating a configuration example of the allocation number derivation table. The allocated number deriving table 21 of the present embodiment is a table for deriving the number to be allocated as a common control channel from the total number of registered mobile stations. They are stored in association with each other.
[0054]
Here, the operation of the spreading code allocating unit 14 which is a feature of the present embodiment will be described. In the present embodiment, only operations different from those of the previously described fourth embodiment will be described.
[0055]
When allocating a common control channel to a new mobile station, the spreading code allocating unit 14 calculates the total number of registered mobile stations using the registered mobile station number storage table 17, and based on the total number of registered mobile stations, determines the number of allocated mobile stations. Then, the number of common control channels to be allocated is derived from 21. For example, when the total number of registered mobile stations is 35, the number to be allocated is three.
[0056]
As described above, in the present embodiment, the number of common control channels to be allocated is derived based on the total number of registered mobile stations. Accordingly, in addition to the effects of the first to third embodiments described above, a necessary and sufficient number of common control channels can be further allocated to the mobile station. In addition, since a necessary and sufficient number of common control channels can be allocated, it is possible to eliminate a reception operation for an unnecessary common control channel, and accordingly, it is possible to significantly suppress the power consumption of the mobile station. For the same reason, it is possible to further reduce the possibility that each mobile station to which the same control channel is assigned competes.
[0057]
Embodiment 6 FIG.
In the above-described embodiment, “average usage rate” and “the number of all registered mobile stations” are used as indices for determining the number of common control channels to be allocated. "Average non-selection rate" is used as a decision index. Note that the same components as those of the fourth embodiment described above are denoted by the same reference numerals, and description thereof will be omitted. In the present embodiment, an unselectable rate storage table 18 is used instead of the usage rate storage table 16.
[0058]
FIG. 11 is a diagram illustrating a configuration example of the allocation number derivation table. The allocation number derivation table 21 according to the present embodiment is a table for deriving the number to be allocated as a common control channel from the average non-selection rate, and stores the average non-selection rate and the number in each average non-selection rate range in association with each other. Have been.
[0059]
Here, the operation of the spreading code allocating unit 14 which is a feature of the present embodiment will be described. In the present embodiment, only operations different from those of the above-described fourth or fifth embodiment will be described.
[0060]
When allocating a common control channel to a new mobile station, the spreading code allocating unit 14 obtains an average non-selectable rate using the non-selectable rate storage table 18 and allocates from the allocation number deriving table 21 based on the average non-selectable rate. The number of common control channels to be expended is derived. For example, when the average non-selectable rate is 0.9, the number to be assigned is four.
[0061]
As described above, in the present embodiment, the number of common control channels to be allocated is derived based on the average non-selection rate of the common control channels. Accordingly, in addition to the effects of the first to third embodiments described above, a necessary and sufficient number of common control channels can be further allocated to the mobile station. In addition, since a necessary and sufficient number of common control channels can be allocated, it is possible to eliminate a reception operation for an unnecessary common control channel, and accordingly, it is possible to significantly suppress the power consumption of the mobile station. For the same reason, it is possible to further reduce the possibility that each mobile station to which the same control channel is assigned competes.
[0062]
Embodiment 7 FIG.
In the above first to sixth embodiments, the operation at the time of accommodating the mobile station by the base station has been described. However, in the seventh embodiment, when the usage rate between the common control channels is biased due to the detachment of the mobile station, Reassignment of a common control channel to each mobile station will be described. The configurations of the base station and the radio channel control unit are the same as those in FIGS. 1 and 2 of Embodiments 1 to 6 described above, and thus the same reference numerals are given and the description is omitted.
[0063]
Here, the operation of the spreading code allocating unit 14 which is a feature of the present embodiment will be described. FIG. 12 is a flowchart showing the reassignment process of the spreading code assignment unit 14. The activation of the reallocation process is executed at an arbitrary timing. In the present embodiment, only operations different from those of the first embodiment described above will be described.
[0064]
The spreading code allocating unit 14 refers to the usage rate storage table 16 (step S21, step S22, No), and if the bias of the usage rate is detected between the common control channels (step S22, Yes), eliminates the bias. Then, the same processing as in the first embodiment is executed for all mobile stations (steps S23 and S24) (steps S1 to S4). That is, the common control channel is reallocated to all the mobile stations.
[0065]
Note that, in the present embodiment, “utilization rate” is used as an index of reallocation of the common control channel. However, the present invention is not limited to this. For example, the “number of registered mobile stations” or “selectable rate” may be used. The same effect can be obtained even when it is used. More specifically, in this case, instead of the usage rate storage table 16, the previously described registered mobile station number storage table 17 or the non-selectable rate storage table 18 is used, and instead of the processing in steps S1 to S4 described above. The same processing as in the second or third embodiment described above is executed.
[0066]
As described above, in the present embodiment, even when the usage rate is biased among the common control channels due to the departure of the mobile station, common use is made for each mobile station so as to eliminate the bias. The control channel reassignment process is to be performed. Thereby, in addition to the effects of the first to third embodiments, the load between the common control channels can be equalized even when the mobile station leaves.
[0067]
Embodiment 8 FIG.
In Embodiment 7 described above, the number of common control channels to be re-allocated to each base station is a fixed value. In Embodiment 8, however, the number of common control channels to be allocated to each mobile station is determined using the average usage rate of all common control channels. Determine the number of control channels. Note that the configurations of the base station and the radio channel control unit are the same as those in FIGS. 1 and 7 of Embodiments 1 to 6 described above, and thus the same reference numerals are given and the description is omitted.
[0068]
Here, the operation of the spreading code allocating unit 14 which is a feature of the present embodiment will be described. FIG. 13 is a flowchart showing the reassignment process of the spreading code assignment unit 14. The activation of the reallocation process is executed at an arbitrary timing. In this embodiment, only operations different from those of the fourth embodiment described above will be described.
[0069]
The spreading code allocating unit 14 refers to the usage rate storage table 16 (step S21, step S22, No), and detects a bias in the usage rate between the common control channels (step S22, Yes). Is used to determine the average usage rate of the common control channels, and the number of common control channels to be allocated is derived from the allocation number derivation table 21 based on the average usage rate (step S11). After that, the spreading code allocating unit 14 executes the same processing as in the fourth embodiment (steps S1, S2, S12, S4) for all mobile stations (steps S23, S24) so as to eliminate the above bias. . That is, the common control channels for the derived number are reassigned to all the mobile stations.
[0070]
In the present embodiment, “average usage rate” is used as an index for determining the number of common control channels to be allocated. However, the present invention is not limited to this. The same effect can be obtained even when the “impossible rate” is used. More specifically, in this case, instead of the usage rate storage table 16, the previously described registered mobile station number storage table 17 or non-selection rate storage table 18 is used, and the above steps S1, S2, S12, and S4 are performed. Instead of the processing, the same processing as in the fifth or sixth embodiment described above is executed.
[0071]
As described above, in the present embodiment, even when a bias occurs in the usage rate between the common control channels due to the departure of the mobile station, for each mobile station to eliminate the bias, The reallocation processing of the number of common control channels determined by the predetermined derivation processing is performed. Thereby, in addition to the effects of the fourth to sixth embodiments, the load between the common control channels can be equalized even when the mobile station leaves.
[0072]
Embodiment 9 FIG.
In the above first to eighth embodiments, the method of allocating a common control channel to each mobile station has been described. In the ninth embodiment, however, a predetermined number of common control channels to be received by each mobile station has already been set. A description will be given of a method in which the base station selects a common control channel for actually transmitting control information from among the allocated channels. The configurations of the base station and the radio channel control unit are the same as those of the first to eighth embodiments described above with reference to FIG. 1, FIG. 2 or FIG. I do.
[0073]
Here, the operation of the common control channel spreading code selection unit 12 (corresponding to a communication channel selection unit in the claims), which is a feature of the present embodiment, will be described. FIG. 14 is a flowchart showing the processing of the common control channel spreading code selector 12.
[0074]
The common control channel spreading code selection unit 12 refers to the spreading code table 13 and acquires a common control channel that is not currently selected by another mobile station from among common control channels that can be selected by the target mobile station. (Step S31). Then, if there is one selectable common control channel (step S32, No), the common control channel for actually transmitting the control information is determined as the selected channel. On the other hand, if there are a plurality of selectable common control channels (Step S32, Yes), the usage rate of the selectable common control channels is acquired from the usage rate storage table 16 (Step S33). Then, the common control channel with the lowest usage rate is selected as a common control channel for transmitting control information (step S34).
[0075]
In the present embodiment, “utilization rate” is used as a selection index of a common control channel for actually transmitting control information. However, the present invention is not limited to this. For example, “the number of registered mobile stations” or “ The same effect can be obtained even when the “selection impossible rate” is used. More specifically, in this case, the above-described registered mobile station number storage table 17 or non-selectable rate storage table 18 is used instead of the usage rate storage table 16.
[0076]
As described above, in the present embodiment, as the common control channel for actually transmitting the control information, a “low usage rate”, “small number of registered mobile stations” or “low selection disabled rate” common control channel is used. We decided to give priority to it. As a result, the possibility of conflicting transmission requests for control information addressed to each mobile station to which the same control channel is assigned is reduced, and as a result, the possibility of successfully transmitting control information is increased.
[0077]
【The invention's effect】
As described above, according to the present invention, for example, a common control channel with a low usage rate is preferentially assigned to a mobile station. Thereby, there is an effect that the load between the common control channels can be equalized. Further, since the possibility of conflicting control information transmission requests addressed to mobile stations to which the same common control channel is allocated is reduced, the possibility that control information can be transmitted is increased as compared with the related art. Play.
[Brief description of the drawings]
FIG. 1 is a diagram showing a basic configuration of a base station according to the present invention.
FIG. 2 is a diagram illustrating a configuration of a wireless channel control unit.
FIG. 3 is a diagram illustrating a configuration example of a usage rate storage table.
FIG. 4 is a flowchart illustrating processing of a spreading code allocating unit.
FIG. 5 is a diagram illustrating a configuration example of a registered mobile station number storage table.
FIG. 6 is a diagram illustrating a configuration example of an unselectable rate storage table;
FIG. 7 is a diagram illustrating a configuration of a wireless channel control unit.
FIG. 8 is a diagram illustrating a configuration example of an allocation number derivation table.
FIG. 9 is a flowchart showing processing of a spreading code allocating unit.
FIG. 10 is a diagram illustrating a configuration example of an allocation number derivation table.
FIG. 11 is a diagram illustrating a configuration example of an assignment number derivation table.
FIG. 12 is a flowchart illustrating a reassignment process of a spreading code assignment unit.
FIG. 13 is a flowchart showing a reassignment process of a spreading code assignment unit.
FIG. 14 is a flowchart showing processing of a common control channel spreading code selection unit.
FIG. 15 is a diagram for specifically explaining a conventional problem.
FIG. 16 is a diagram for specifically explaining a conventional problem.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 radio channel control unit, 2 data buffer unit, 3 modulation / spreading processing unit, 4 upper layer processing unit, 11 scheduling unit, 12 spreading code selection unit for common control channel, 13 spreading code table, 14 spreading code allocation unit, 15 Spread code table for common control channel, 16 utilization rate storage table, 21 allocated number derivation table.

Claims (18)

A radio base station device that accommodates a plurality of mobile station devices and allocates a predetermined number of communication channels to each of the mobile station devices,
When allocating a communication channel to a newly accommodated mobile station device, communication channel allocating means for allocating the predetermined number of communication channels selected based on the congestion degree of each communication channel,
A wireless base station device comprising: The communication channel allocating unit uses a usage rate as the congestion degree of each communication channel, and gives priority to the predetermined number of communication channels in ascending order of usage rate from all communication channels stored in advance. The radio base station apparatus according to claim 1, wherein The radio base station apparatus according to claim 2, wherein the communication channel allocating unit adaptively determines the predetermined number based on an average usage rate of all communication channels. The communication channel allocating means uses the number of registered mobile station devices as the congestion degree of each communication channel, and sets the predetermined number of mobile stations in the ascending order of the number of registered mobile stations from among all communication channels stored in advance. 2. The wireless base station apparatus according to claim 1, wherein the communication channel is preferentially assigned. The radio base station apparatus according to claim 4, wherein the communication channel allocating unit adaptively determines the predetermined number based on the total number of registered mobile station apparatuses. The communication channel allocating means uses a non-selection rate as the congestion degree of each of the communication channels. The radio base station apparatus according to claim 1, wherein the radio base station apparatus is preferentially assigned. 7. The radio base station apparatus according to claim 6, wherein the communication channel allocating unit adaptively determines the predetermined number based on an average non-selection rate of all communication channels. The communication channel allocating means, when the congestion degree is uneven between the communication channels due to the detachment of the accommodating mobile station device, in the same process as the allocation process for the newly accommodated mobile station device, the bias 2. The wireless base station apparatus according to claim 1, wherein a communication channel reassignment process is performed for each mobile station apparatus so as to eliminate it. The communication channel allocating unit, assuming that the congestion degree is biased, assuming that the usage rate is biased, and performing the reallocation process to eliminate the usage rate bias. The radio base station apparatus according to claim 8, wherein The radio base station apparatus according to claim 9, wherein the communication channel allocating means adaptively determines the number of communication channels to be allocated at the time of the reallocation processing based on an average usage rate of all communication channels. The communication channel allocating means, as a case where the congestion degree is biased, assuming a case where a bias occurs in the number of registered mobile station devices, and performs the reallocation process so as to eliminate the bias in the number of registered mobile station devices. The radio base station apparatus according to claim 8, wherein the radio base station apparatus is implemented. The radio base station apparatus according to claim 11, wherein the communication channel allocating unit adaptively determines the number of communication channels to be allocated at the time of the reallocation processing based on the number of all registered mobile station apparatuses. The communication channel allocating means, as a case where the congestion degree is biased, assuming that a non-selection rate is biased, and performing the reallocation process so as to eliminate the non-selection rate bias. The radio base station apparatus according to claim 8, wherein: 14. The radio base station apparatus according to claim 13, wherein the communication channel allocating unit adaptively determines the number of communication channels to be allocated at the time of the reallocation processing based on an average non-selection rate of all communication channels. . A radio base station device that accommodates a plurality of mobile station devices and allocates a predetermined number of communication channels to each of the mobile station devices,
When transmitting predetermined information to a specific mobile station device, the predetermined number of communication channels allocated to the mobile station device are replaced by communication channels not currently selected by other mobile station devices (selectable communication channels). If there is, based on the congestion degree of the selectable communication channel, a communication channel selecting means for selecting a communication channel for transmitting the predetermined information,
A wireless base station device comprising: The communication channel selecting means uses a usage rate as the congestion degree of the selectable communication channel, and selects a communication channel having the lowest usage rate as a communication channel for transmitting the predetermined information. The radio base station apparatus according to claim 15, wherein The communication channel selecting means uses the number of registered mobile stations as the congestion degree of the selectable communication channel, and selects a communication channel with the least number of registered mobile stations as a communication channel for transmitting the predetermined information. The wireless base station device according to claim 15, wherein: The communication channel selecting means uses a non-selection rate as the congestion degree of the selectable communication channel, and selects a communication channel with the lowest non-selection rate as a communication channel for transmitting the predetermined information. The radio base station apparatus according to claim 15, wherein

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