JP3374971B2 - Channel allocation method and apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a channel allocation method and device in a base station corresponding to a communication control station equipped with a directional antenna.

[0002]

2. Description of the Related Art In wireless communication, especially mobile communication, a plurality of users communicate with each other through one base station. At that time, each terminal (user) secures a communication channel during the communication period and releases the communication channel at the same time when the communication is completed. By thus securing the communication channel only during the communication time, the communication channel can be used among a plurality of users only when necessary, and the channel utilization efficiency can be improved. Normally, a base station has a plurality of communication channels, and a terminal desiring new communication is
This is notified to the base station via a control channel prepared separately from the communication channel, and the base station allocates a vacant communication channel to each terminal. Such a series of operations is called channel allocation processing.

A conventional channel allocation method for performing such channel allocation processing will be described with reference to the configuration of the base station shown in FIG. Here, 100 is a base station to which channel allocation is performed, and is provided with a base station antenna 102. The base station 100 includes a base station antenna 1
Signal processing unit 103 that controls the signal transmitted and received in 02.
The control signal received on the control channel is supplied to the control signal receiving unit 104, and the communication signal during communication received on the communication channel is supplied to the communication channel unit 108. In the control signal receiving unit 104, the terminal ID of the terminal that has transmitted the control signal is recognized from the control signal, and the reception beam of which of the plurality of beams formed by the base station antenna 102 has been received. The number is detected.

Next, the vacant channel status at the reception beam number detected by the calculation unit 5 is confirmed, and the channel selection unit 106 detects whether or not there is a vacant channel. If there is a free channel, a free channel with a high priority is selected from the free channels and assigned to the terminal that transmitted the control signal. Then, the channel information of the assigned communication channel is transmitted from the control signal transmission unit 107. The transmitted channel information is transmitted by the beam of the beam number detected from the base station antenna 102 to the terminal via the signal processing unit 103.
If the received signal is a communication signal during communication, the received signal is supplied to the communication channel unit 108, and the communication signal is sent to the other party's terminal.

The control channel for transmitting the control signal and the communication channel for transmitting the communication signal may be set to different carrier frequencies or may be set to the same carrier frequency. FIG. 8 shows a channel format when a control channel and a communication channel are set on the same carrier frequency. In this format, one carrier is divided into a plurality of time slots, for example, two channels are set as the control channel 120 and the remaining N channels # 1 to #N are set as the communication channel 121. In addition, the base station antenna 102 includes a plurality of antenna elements, and is an omnidirectional antenna that is omnidirectional or a directional sector antenna in which multiple beams are formed. The antenna pattern of the base station antenna 102 is fixed for both antennas.
02 is designed to cover a given service area.

When the channel formats of the control channel 120 and the communication channel 121 shown in FIG.
FIG. 9 shows a flowchart of the channel allocation process performed by the base station 100 having the configuration shown in FIG. When a terminal in the service area covered by the fixed antenna pattern by the base station antenna 102 desires to start a new communication, the terminal desiring the communication is controlled by the control channel 1
20 is used to transmit a control signal desired to be communicated to the base station 100.
To the base station 100. When a control signal is received by the base station antenna 102 in the base station 100 (step S100), a channel allocation process is started, and a terminal ID of a terminal desiring communication is detected from the received control signal (step S10).
1) Processing is performed. Further, a process of specifying the beam number B of the beam at the base station antenna 102 in which the control signal is detected (step S102) is performed.

[0007] Next, the base station 100 refers to the channel state table stored in the channel state storage unit 105, and the channel selection unit 106 performs a process of searching for an empty uplink channel (step S103).
-Step S107). The channel state table stored in the channel state storage unit 105 stores information about the currently used communication channel and the unused communication channel for each beam of the base station antenna 102. For example,
In the channel state table shown in FIG. 10, the number of beams of the base station antenna 102 is 6, and in the first communication channel # 1, beam 1 (Beam 1) and beam 3 (Bea
m3) are in use, beam 3 (Beam3) is in use in the second communication channel # 2, and beam 2 (Beam2) and beam 6 (Bea) in the third communication channel # 3 are in use.
m6) and are said to be in use.

When searching for an empty channel by referring to such a channel state table, for each beam for each communication channel n from the first communication channel # 1 to the Nth communication channel #N in the channel state table Search for usage and find available free channels. Specifically, the communication channel n is set to the communication channel # 1 in step S103, and the communication channel n is set in step S10.
In step 4, the communication channel n is set to the communication channel # 1. Next, the availability of each of the beams 1 to 6 in the communication channel # 1 set in step S105 is confirmed. Further, in step S106, it is determined whether or not n is N or more. In this case, since n = 1, it is determined to be NO, and the process branches to step S107. This step S1
At 07, n is incremented by "1" to "2", and the process proceeds to step S104. This step S10
4, the communication channel n is set as the communication channel # 2, and the beam 1 in the communication channel # 2 is set in step S105.
~ The availability of each beam 6 is confirmed. Hereinafter, the same process is repeated until n becomes N.

As a result, the first communication channel # 1 to the Nth communication channel
With respect to each communication channel n up to the communication channel #N, it is possible to search the usage status of each beam and detect an available empty channel. And step S
It is determined in step 106 that n is equal to or greater than N and step S
In step 108, it is determined whether or not an available channel that can be used in the above process is detected. Here, if it is determined that there is an empty channel, an empty channel with a high priority among the empty channels is detected in step S109. In this case, data regarding the use priority order is set in the empty channels of the channel state table and is stored in the priority order display column (not shown). An empty channel with a high priority is detected by referring to this priority display field. Various schemes have been proposed for the priority order. For example, a scheme in which the use priority order is set higher from the one having a smaller interference power intensity of each channel can be used.

The free channel having a high priority detected in this way is assigned to the terminal desiring to start a new communication as a used communication channel in step S110. This assigned channel information is notified to the terminal that desires to start new communication using the downlink control channel, and that terminal starts uplink communication using the notified communication channel. If it is determined in step S108 that there is no available free channel, the process branches to step S111 to determine that communication is not possible, and that effect is notified to the terminal that desires to start new communication. In this case, the terminal cannot start new communication.

[0011]

As described above, the conventional channel allocation method is a channel allocation process for an omnidirectional antenna or a directional antenna having a fixed beam. Therefore, in the conventional channel allocation method, it is possible to allocate channels to terminals in a fixed service area by searching for a free state of a predetermined channel.

However, recently, it has been considered to adaptively change the beam pattern in accordance with the direction in which a terminal exists by using an adaptive array antenna or the like. In particular, the recent technological development of the adaptive array antenna is remarkable, and it is approaching a practical level in terms of hardware. The adaptive array antenna can adaptively change the beam pattern according to the moving direction of the terminal. Therefore, the beam coverage area also changes with time, and the service area becomes variable. Further, since the beam pattern is changed according to the movement of the terminal performing communication, good communication quality can be secured as compared with the case of the conventional fixed beam pattern.

When such a beam pattern is adaptively changed, the conventional channel allocation method based on a fixed service area cannot be adapted. Therefore, there is a need for an adaptive and flexible channel allocation method suitable for adaptive array antennas. However, no channel allocation method suitable for an adaptive array antenna that can adaptively change the beam pattern and that can effectively use the spatial domain has been proposed, and adaptive and flexible channel allocation is performed even using an adaptive array antenna. There was a problem that I could not do it.

Therefore, an object of the present invention is to provide a channel allocation method and apparatus suitable for an adaptive array antenna capable of adaptively changing a beam pattern.

[0015]

In order to achieve the above object, a first channel allocation method according to the present invention is a channel allocation in a communication control station equipped with antenna means capable of adaptively changing a beam pattern. A method for obtaining a spatial correlation value between a terminal desiring communication and another terminal in communication when the control signal desiring communication from the terminal is received from the received control signal. The communication channel is calculated based on the received data obtained and the received data from the other terminal in communication, and the communication channel in which the spatial correlation value obtained by the calculation is reduced is desired for the communication. It is to be assigned to the terminal
The antenna means is provided with the spatial correlation value.
Performs calculations using the signal correlation matrix between multiple antenna elements
I try to get it.

[0016]

Further, a second channel allocation method according to the present invention which can achieve the above object is a channel allocation method in a communication control station provided with antenna means capable of adaptively changing a beam pattern. When receiving a control signal from the terminal, the signal-to-interference power ratio between the terminal desiring the communication and the other terminal in communication is the received data obtained from the received control signal. And calculating for each communication channel based on the received data from the other terminal in communication, and using the signal-to-interference power ratio obtained by the calculation to allocate the communication channel to the desired terminal. ing.

In order to achieve the above object, a first channel allocating device according to the present invention is a channel allocating device in a communication control station, which comprises an antenna means capable of adaptively changing a beam pattern, and is a terminal. From the received control signal, the spatial correlation value in the communication between the terminal desiring the communication and the other terminal in communication when the control signal desiring the communication is received from the received data. And a calculation means for obtaining each communication channel based on the received data from the other terminal in communication, and a communication channel having a small spatial correlation value obtained by the calculation means for the communication. and a channel selection unit assigned to the desired terminal, but the computing means, the a
Signal correlation line between multiple antenna elements included in the antenna means
The spatial correlation value is obtained by performing an operation using a column.
Trying to get .

[0019]

A second channel allocating apparatus according to the present invention that can achieve the above object is a channel allocating apparatus in a communication control station equipped with an antenna unit capable of adaptively changing a beam pattern, which is a terminal. When receiving a control signal desired to communicate from, the signal-to-interference power ratio between the terminal desiring the communication and another terminal in communication, the received data obtained from the received control signal, A computing unit adapted to obtain each communication channel based on the received data from the other terminal in communication, and a terminal desiring the communication channel using the signal-to-interference power ratio obtained by the computing unit. And a channel selecting means for allocating to the channel.

In such a first channel allocation method and apparatus of the present invention, a spatial correlation value between a terminal desiring communication and another terminal in communication is calculated for each communication channel and obtained by the calculation. Since the communication channel with the reduced spatial correlation value is assigned to the terminal that desires communication, it is possible to adaptively perform channel assignment in the spatial domain. With this, it is possible to assign a communication channel to a terminal that desires to communicate according to the adaptive beam pattern change of the adaptive array antenna,
While arranging one spatially suitable communication channel,
It is possible to accommodate a plurality of users on the same carrier communication channel at the same time.

Further, in the second channel allocation method and apparatus of the present invention, the spatial correlation value is obtained by performing an operation using a signal correlation matrix between a plurality of antenna elements included in the antenna means. There is. The signal correlation matrix between the plurality of antenna elements is calculated and held in the adaptive array antenna processing. Therefore, it is possible to reduce the amount of calculation when calculating the spatial correlation value for channel selection. further,
A communication channel can be assigned to a terminal desiring communication in accordance with an adaptive beam pattern change of the adaptive array antenna, and one spatially suitable communication channel can be allocated while simultaneously providing a plurality of users with the same carrier. It may be possible to accommodate a communication channel.

Furthermore, in the third channel allocation method and apparatus of the present invention, the signal-to-interference power ratio between a terminal desiring communication and another terminal in communication is calculated for each communication channel, and the obtained signal pair is calculated. A communication channel with a large interference power ratio is assigned to a terminal that desires communication. As a result, it becomes possible to select a channel based on the signal-to-interference power ratio (SINR) when it is assumed that a terminal desiring communication actually performs communication, and it is better to select a communication channel with good communication quality. You will be able to do it accurately. By this means, it is possible to allocate communication channels to terminals that wish to communicate according to adaptive beam pattern changes of the adaptive array antenna, and to arrange one spatially suitable communication channel while simultaneously allocating multiple users. The communication channels of the same carrier can be accommodated.

[0024]

FIG. 1 shows the configuration of a base station to which an embodiment of the first channel allocation device of the present invention, which embodies the first channel allocation method of the present invention, is applied.
In FIG. 1, a base station 1 corresponds to a communication control station that controls communication in a communication service area to which a terminal 9 such as a mobile phone belongs. The base station 1 is provided with an adaptive array antenna 2 capable of changing a plurality of beam patterns according to the movement of one or more terminals in communication located in the communication service area. The adaptive array antenna 2 includes a plurality of antenna elements. The base station 1 is provided with a signal processing unit 3 that controls signals transmitted and received by the adaptive array antenna 2, and the control signal received on the control channel is supplied to the control signal receiving unit 4 and is transmitted on the communication channel. The received communication signal during communication is supplied to the communication channel unit 8.

When the terminal 9 desires a new communication, the control channel is used to transmit a control signal to that effect. This control signal is received by the adaptive array antenna 2 and supplied to the control signal receiving unit 4 by the signal processing unit 3. In the control signal receiving unit 4, the terminal ID of the terminal 9 that has transmitted the control signal is recognized from the received control signal, and the received signals of the plurality of antenna elements forming the adaptive array antenna 2 are in the form of signal vector. To be detected. Further, at this time, the communication signal received by the adaptive array antenna 2 when another terminal (not shown) is in communication is transmitted from the communication channel unit 8 to the other terminal. further,
The communication signal is detected in the form of a signal vector in the communication channel unit 8 and supplied to the arithmetic unit 5.

In the arithmetic unit 5, the signal vector U _d of the control signal transmitted and received from the terminal 9 and the signal vector U of the communication signal transmitted and received from the other terminal in communication.
_A spatial correlation calculation is performed using _k and a spatial correlation between the terminal 9 that desires new communication and another terminal that is in communication is calculated. Specifically, the evaluation function Q shown in the following equation (1) is used as a function showing a spatial correlation, and the evaluation function Q is calculated for each communication channel.
I try to get the value. This evaluation function Q is expressed by the following equation. Q = Σ _k (U _k ^H · U _d ) ² + (U _N ^H · U _d ) ² (1) where U _N is the noise vector of the receiving means in the base station 1, and U _k Is a signal vector of a terminal that is communicating in a specific communication channel, Σ _k means that the sum is obtained for each terminal that is communicating in the specific communication channel, and “H” is a transposed conjugate. I mean.

When the Q value for each channel obtained by calculating the evaluation function Q in this way is calculated, the spatial correlation is high when the Q value is large, and the spatial correlation is calculated when the Q value is small. Will be low. Therefore, the channel selection unit 6
Then, the communication channel corresponding to the smallest Q value of the calculated Q values is assigned to the terminal 9 that desires new communication. The channel information of the assigned communication channel is transmitted from the control signal transmitting unit 7 to the terminal 9 desiring to start new communication from the base station 1 via the signal processing unit 3 and the adaptive array antenna 2 using the downlink control channel. Be notified. The notified terminal 9 starts uplink communication using the communication channel based on the channel information.

The channel formats of the control channel and communication channel are the same as the channel formats shown in FIG. Here, in the format shown in FIG. 8, the control channel is 2 channels and the communication channel is N channel, and these (2 + N) channels are 1 channel.
The frame is a frame and is repeated periodically. However, the channel format shown in FIG. 8 is an example, and the present invention is not limited to this channel format.

The configuration of the adaptive array antenna 2 is shown in FIG. 2 (a). The adaptive array antenna 2 includes, for example, four antenna elements 10, 11, 1.
2 and 13 are arranged at each vertex of the rectangle. The signal vector U of the received signal received by such an adaptive array antenna 2 is expressed by the following equation (2).

[Equation 1] However, in the equation (2), a1, a2, a3, and a4 are reception signals represented by complex numbers received by the antenna elements 10, 11, 12, and 13. This received signal a
As shown in FIG. 2B, 1, a2, a3, a4 are converted into digital data and stored in the storage means as a signal vector U.

When a communication channel is newly assigned to a terminal desiring to communicate and communication is performed using the communication channel, the beam pattern of the adaptive array antenna 2 is directed to that terminal. For this reason, the four antenna elements 10, 11, 12, and 13 forming the adaptive array antenna 2 have
As shown in (b), the weight portions 14, 15, 1 are respectively
6, 17 are provided and weighted. For example, the weight units 14, 15, 1 are added to the received signals from the terminal 9 received by the antenna elements 10, 11, 12, 13.
Predetermined weights are multiplied in 6 and 17, and the received signals multiplied by the weights are combined in the combining unit 18 to be a communication signal. As a result, the beam pattern of the adaptive array antenna 2 at the time of communication comes to the terminal. Since the weight is composed of the amplitude component and the phase component, the weight units 14, 15, 16, 1
The 7 weights w1, w2, w3, and w4 are represented by complex numbers.

Here, the weight portions 14, 15, 16, 1
An example of a method for determining the weights w1, w2, w3, w4 of 7 will be described. If the weights w1, w2, w3, w4 are represented by the weight W as in the following equation (3),

[Equation 2] The weight W is obtained by the following equation (4). W = Φ ⁻¹ · U _d (4) However, in the expression (4), Φ ⁻¹ is an inverse matrix of the correlation matrix Φ, and normally the correlation matrix Φ can be calculated by the following expression (5). Φ = Σ _k (U _k ^H · U _k ) + (U _N ^H · _UN ) (5) However, in the equation (5), _UN is a noise vector of the receiving means, and U _k is within a specific communication channel. Is a signal vector of a terminal that is communicating, and Σ _k means to take the sum of the terminals that are communicating in a specific communication channel, and “H” means transposed conjugate. The method for determining the weight W in this way is as follows.
rix Inversion) method is called. The number of antenna elements and the arrangement of antenna elements are not limited to the configuration shown in FIG. 2 and can be set arbitrarily.

In FIG. 3, a channel state table showing the calculation result is stored in the arithmetic unit 5, and an example of this channel state table is shown in FIG. The channel state table shown in FIG. 3 stores the number of users for each communication channel, signal vector information regarding each of the users User1 to UserK in communication, noise vector information, and a Q value that is a calculation result. In this channel state table, for example, the number of users is “2” in the communication channel # 1, and the user User1
And user User2 is in communication. This user User1
Signal vector information of the user User2 signal vector U _11, there is a signal vector U ₁₂ and. Signal vector U
₁₁ and U ₁₂ are calculated using the above equation (2). Further, the noise information in the communication channel # 1 is the noise vector U _N, and the Q value calculated using the above equation (1) is, for example, “1.21”.

In the communication channel # 2, the number of users is "3", and the user User1, user User2 and user User
3 is said to be communicating. This User User1, User User
The signal vector information of 2 and the user User3 is a signal vector U ₂₁ , a signal vector U ₂₂ , and a signal vector U ₂₃ . The signal vectors U ₂₁ , U ₂₂ , and U ₂₃ are calculated using the above equation (2). Further, the noise information in the communication channel # 2 is set as the noise vector U _N, and the above equation (1) is used.
The Q value calculated by using is set to, for example, “1.57”. Furthermore, the number of users is “1” in communication channel # 3.
The user User1 is in communication. The signal vector information of the user User1 is the signal vector U ₃₁ . The signal vector U ₃₁ is calculated using the above equation (2). Furthermore, the noise information in the communication channel # 3 is the noise vector U _N, and the Q value calculated using the above equation (1) is, for example, “0.15”. Furthermore, the number of users is “5” in the communication channel #N, and the user User1, the user User2, and the user User3 are in communication. This user User1, user User2 and user
User3 signal vector information of the signal vector U _N1, the signal vector U _N2, there is a signal vector U _N3. The signal vectors _UN1 , _UN2 , _UN3 are calculated using the above equation (2). Further, the noise information in the communication channel #N is the noise vector U _N, and the Q value calculated using the above equation (1) is, for example, “0.83”.

FIG. 4 shows a flowchart of the channel allocation process executed in the base station 1 having the configuration shown in FIG. When a terminal 9 in the service area covered by the adaptive array antenna 2 by the base station 1 desires to start a new communication, the terminal 9 desiring the communication uses the uplink control channel 120 shown in FIG. The control signal is transmitted to the base station 1 to notify the base station 1 to that effect. At this time, the base station 1 transmits to the control channel 120 a control signal related to the desire of communication according to a predetermined method. In the base station 1, when the signal processing unit 3 receives the control signal (step S1), the channel allocation process is started, and the process of detecting the terminal ID of the terminal desiring communication from the received control signal (step S2). Is done. At the same time, the strength and phase of the signal received by each antenna element 10 to 13 of the adaptive array antenna 2 are measured. The extraction of the signal strength and the phase in each antenna element 10 to 13 can be performed by inserting a known signal into the signal.

Each measured antenna element 10
The intensities and phases at ˜13 are stored in the calculation unit 5 as the signal vector U _d shown in (2) above. Each element of the signal vector U _d stores the strength and phase of the signal received by each antenna element 10 to 13 in the form of a complex number. Although the channel state table is stored in the arithmetic unit 5, the signal vectors U ₁₁ , U ₁₂ , of the terminals (User1 to UserK) currently communicating in the channel state table are stored.
U ₂₁ , U ₂₂ , U _23, ..., U _N3 are calculated based on the reception data of each communication channel # 1 to #N in the previous frame. Signal vectors U ₁₁ , U ₁₂ , U ₂₁ , U ₂₂ , U ₂₃
... U _N3 can be calculated using the above equation (2) based on the known signal included in the communication signal of each terminal during communication. Further, the noise level U _N is set based on the noise parameter of the receiving means of the base station 1 at the installation stage of the base station 1. At the initial installation of the base station 1 or at the initial operation stage of the system, only the noise level U _N in the channel state table has a positive value, and the signal vectors U ₁₁ , U ₁₂ , U ₂₁ , U ₂₂ , U ₂₂ , U ₂₂ . ₂₃・ ・ ・_UN3・ ・ ・
All start with "0".

In the cycled processing of steps S4 to S8, the Q value for each communication channel is calculated in the arithmetic unit 5. That is, the Q value which is the calculation result of the evaluation function Q indicating the spatial correlation is calculated using the above (1) and stored in the column of each communication channel of the channel state table. Specifically, communication channel n is set to communication channel # 1 in step S4, and Q is set in step S5.
The communication channel n whose value is calculated is defined as communication channel # 1. Next, the communication channel # set in step S6
The signal vector U ₁₁ , U ₁₂ of the terminal in communication in 1 is used as the signal vector U _k , and the above equation (1) is calculated by using the signal vector U _d and the noise vector U _N of the terminal 9 desiring communication, The Q value of channel # 1 is calculated. Further, in step S7, it is determined whether or not the communication channel n has reached the communication channel N. In this case, since the communication channel n is the communication channel # 1, it is determined to be NO and the process branches to step S8. . In step S8, the communication channel n is incremented by "1" to n = 2, and the process returns to step S5.

The communication channel n for which the Q value is calculated in step S5 is set to the communication channel # 2, and step S6
The signal vector U _21, U _22, U ₂₃ of the terminal in the communication in the communication channel # 2 is set as a signal vector U _k at using a signal vector U _d and the noise vectors U _N terminal 9 wishes to communicate The above equation (1) is calculated to calculate the Q value of communication channel # 2. The calculation process of the Q value for each communication channel is repeatedly performed until the communication channel n reaches the communication channel N. As a result, the channel state table as shown in FIG. 3 can be obtained. If the Q value indicating the spatial correlation is high in this channel state table, it may be determined that the spatially existing directions of the terminal 9 desiring communication and the terminal currently in communication are close to each other. it can. Further, when the Q value is small, it can be seen that the spatial presence directions of the terminal 9 desiring communication and the terminal currently in communication are not close.

Therefore, in step S9, the channel state table is referred to and the communication channel n having the minimum Q value is selected. When the channel state table is as shown in FIG. 3, channel # 3 is selected.
The selected communication channel n is the communication channel having the lowest spatial correlation value with the terminal 9 desiring to communicate, which means that the communication channel n is spatially distant from the other terminals currently in communication. . Next, it is determined whether or not the Q value of the communication channel n selected in step S10 is below a predetermined level. This is because if the Q value is not lower than the predetermined level, the spatial communication direction is close to other communication channels in communication, and good communication cannot be performed due to mutual interference. Here, when the Q value of the selected communication channel n is determined to be equal to or lower than the predetermined level, the communication channel n selected in step S11 is determined as the communication channel to be assigned to the terminal 9 which desires to start new communication. To be done.

The determined channel information of the communication channel n is notified to the terminal 9 that desires new communication using the downlink control channel, and the terminal 9 starts the uplink communication using the notified communication channel n. To do. The base station 1 calculates the above equation (4) using the signal vector U _d in the terminal 9 to calculate the weights w1, w2, w of the antenna elements 10 to 13 of the adaptive array antenna 2.
3, w4 is calculated. Then, when performing communication with the terminal 9 that desires new communication, the calculated weight w
1, w2, w3, w4 are antenna elements 10 to 1
Set to 3 for communication. Further, when another terminal other than the terminal 9 communicates, the weights w1 ′, w2 ′, w3 ′ calculated by performing the calculation of the above equation (4) using the signal vector U _d in the other terminal. , W4 ′ are set in the respective antenna elements 10 to 13 to perform communication. Furthermore, if the Q value of the selected communication channel n is not determined to be equal to or lower than the predetermined level, the process branches to step S12 and communication is not performed. Terminal 9 that is determined to be available and wishes to communicate
No communication channel will be assigned to. In addition,
Furthermore, when a terminal desiring new communication accesses the base station 1, a signal vector of the terminal currently in communication in the channel state table and The Q value for each communication channel is recalculated and rewritten to the latest value.

In summary, when a terminal desiring a new communication occurs, a Q value indicating a correlation value is calculated for each communication channel. A communication channel suitable for use is determined from the calculated Q value and assigned to the terminal. By adaptively allocating communication channels spatially separated from other terminals in communication in this way, efficient channel allocation can be enabled. Also, after allocating the communication channel, during the period of communication,
The SMI described above in the adaptive array antenna 2
By performing adaptive array processing such as a method, the beam pattern is made to follow the direction of the terminal during communication.

In the embodiment of the first channel allocation device of the present invention described above, in the arithmetic unit 5, the signal vector U _{d of the} terminal desiring to communicate and the signal vector U _k of the terminal in communication are used as the evaluation function Q. I try to use the product. In the second embodiment of the channel allocation device of the present invention, instead, the evaluation function Q ₂ is determined using the correlation matrix Φ over the entire communication channel and the signal vector U _{d of the} terminal desiring to communicate. . An embodiment of the second channel allocation device of the present invention will be described below.

The configuration of the base station to which the embodiment of the second channel assignment device of the present invention which embodies the second channel assignment method of the present invention is applied is the same as that of FIG. 1 described above. The calculation executed in the calculation unit 5 becomes different. In the calculation section 5, the calculation of the following expression (6) is performed as the evaluation function Q ₂ . Q ₂ = U _d ^H · Φ · U _d (6) where U _d is the signal vector of the terminal that desires new communication, and Φ is the correlation matrix calculated by the above formula (5). Φ, and “H” means transposed conjugate. As described above, if the calculation of the evaluation function Q ₂ is performed using the equation (6), the load of the calculation process can be reduced. The reason will be described below. When performing the adaptive array processing using the SMI method, it is necessary to calculate the correlation matrix Φ shown in the equation (5), and the calculation unit 5 separates each communication in the adaptive array processing from the calculation processing in the channel allocation. The value of the correlation matrix Φ corresponding to the channel is calculated and held. That is, the value of the correlation matrix Φ held in this adaptive array processing can be used to calculate the evaluation function Q ₂ obtained at the time of channel allocation.

Further, the channel state table used in the embodiment of the second channel assignment device of the present invention is different from the channel state table of the second channel assignment device of the present invention. A channel state table in the second channel allocation device of the present invention is shown in FIG. As shown in FIG. 5, the channel state table stores the correlation matrices Φ _{1 to} Φ _N calculated for the respective communication channels # 1 to #N and the Q ₂ value which is the calculation result of the evaluation function Q _2. There is. This correlation matrix Φ is calculated using the above equation (5) based on the received signal of the same communication channel in the previous frame in the adaptive array processing. Then, the evaluation function Q ₂ is a value calculated by performing the calculation of the equation (6) using the correlation matrix Φ and the signal vector U _d of the terminal 9 that newly desires communication.

By substituting the equation (5) into the equation (6), the evaluation function Q ₂ becomes: Q ₂ = Σ _k (U _k ^H · U _d ) ² + (U _N ^H · U _d ) ² Can be rewritten and becomes the same as the evaluation function Q in the above equation (1). However, as mentioned above, the second
In the channel allocating device, the calculation amount of the evaluation function Q ₂ can be reduced by using the correlation matrix Φ.

The second channel allocation of the present invention described above
In the embodiment of the patching device, the communication section is used in the calculation unit 5.
Correlation matrix Φ for the entire channel and signal vector of the terminal wishing to communicate
Le U _dUsing the evaluation function Q₂I am trying to decide.
In the embodiment of the third channel allocation device of the present invention
Is the inverse matrix Φ of the correlation matrix Φ instead of^-1Communication end
End signal vector U_dUsing the evaluation function Q₃I will decide
I am sorry. Below, the third channel assignment of the present invention will be described.
An embodiment of the apparatus will be described.

The configuration of the base station to which the third embodiment of the channel allocation device of the present invention, which embodies the third channel allocation method of the present invention, is applied is the same as that shown in FIG. The calculation executed in the calculation unit 5 becomes different. In the arithmetic unit 5, the following equation (7) is calculated as the evaluation function Q ₃ . Q ₃ = U _d ^H · Φ ⁻¹ · U _d (7) where U _d is the signal vector of the terminal that desires new communication, and Φ ⁻¹ is calculated by the formula (5). Is an inverse matrix of the correlation matrix Φ, and “H” means transposed conjugate. As described above, when the calculation of the evaluation function Q ₃ is performed using the expression (7), the load of the calculation process can be reduced. The reason will be described below. When the adaptive array processing is performed using the SMI method, it is necessary to calculate the weight W shown in the equation (4), and the calculation unit 5 separates each communication channel from the calculation processing in the channel allocation in the adaptive array processing. The value of the inverse matrix Φ ⁻¹ of the correlation matrix Φ corresponding to is calculated and held. That is, the value of the inverse matrix Φ ⁻¹ of the correlation matrix Φ held in this adaptive array processing can be used to calculate the evaluation function Q ₃ obtained at the time of channel allocation.

The channel state table used in the embodiment of the third channel assignment device of the present invention is different from the channel state table of the third channel assignment device of the present invention. FIG. 6 shows a channel state table in the third channel allocation device of the present invention. As shown in FIG. 6, in the channel state table, the inverse matrices Φ ₁ ^{−1 to} Φ _N ^{−1 of} the correlation matrices Φ _{1 to} Φ _N calculated for each communication channel # 1 to #N and the evaluation function Q _{3 are used.}
The Q ₃ value which is the result of the calculation is stored. The inverse matrix Φ ⁻¹ of the correlation matrix Φ is an inverse matrix of the correlation matrix Φ calculated by using the above equation (5) based on the received signal of the same communication channel in the previous frame in the adaptive array processing. The evaluation function Q ₃ is the inverse matrix Φ ⁻¹ of the correlation matrix Φ and the signal vector U of the terminal 9 newly wishing to communicate.
It is a value calculated by performing the calculation of the equation (7) using _d and.

The evaluation function Q ₃ represents the theoretical value of the signal-to-interference power ratio (SINR) that can be achieved when it is assumed that the terminal 9 desiring communication has performed communication on the communication channel. Therefore, the higher the evaluation function Q _{3, the} better the channel to be secured. That is, in the third channel allocation device of the present invention, the evaluation function Q ₃ is calculated for each communication channel, and the terminal 9 that desires communication with the communication channel having the highest Q ₃ value as the calculation result. By allocating, it is possible to perform channel allocation based on SINR when it is assumed that communication is actually performed.

[0049]

As described above, in the first channel allocation method and apparatus of the present invention, the spatial correlation value between a terminal desiring communication and another terminal in communication is calculated for each communication channel, and calculated. Since the communication channel having the smaller spatial correlation value obtained by the above is allocated to the terminal that desires communication, the channel can be adaptively allocated in the spatial domain. By this means, it is possible to allocate communication channels to terminals that wish to communicate according to adaptive beam pattern changes of the adaptive array antenna, and to arrange one spatially suitable communication channel while simultaneously allocating multiple users. The communication channels of the same carrier can be accommodated.

In the second channel allocation method and apparatus of the present invention, the spatial correlation value is obtained by performing the calculation using the signal correlation matrix between the plurality of antenna elements included in the antenna means. The signal correlation matrix between the plurality of antenna elements is calculated and held in the adaptive array antenna processing.
Therefore, it becomes possible to reduce the amount of calculation when the evaluation function Q ₂ is calculated for channel selection. Furthermore, a communication channel can be assigned to a terminal desiring communication in accordance with an adaptive beam pattern change of the adaptive array antenna, and a single spatially suitable communication channel can be allocated while simultaneously allocating a plurality of users with the same communication channel. It may be possible to accommodate it in the carrier's communication channel.

In the third channel allocation method and apparatus of the present invention, the signal-to-interference power ratio between a terminal desiring communication and another terminal in communication is calculated for each communication channel, and the obtained signal-to-interference power ratio is calculated. The increased communication channel is assigned to the terminal that desires communication. As a result, it becomes possible to select a channel based on the signal-to-interference power ratio (SINR) when it is assumed that a terminal desiring communication actually performs communication, and it is better to select a communication channel with good communication quality. You will be able to do it accurately. By this means, it is possible to allocate communication channels to terminals that wish to communicate according to adaptive beam pattern changes of the adaptive array antenna, and to arrange one spatially suitable communication channel while simultaneously allocating multiple users. The communication channels of the same carrier can be accommodated.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a base station to which an embodiment of a first channel allocation device of the present invention, which embodies a first channel allocation method of the present invention, is applied.

FIG. 2 is a diagram showing a configuration of an adaptive array antenna included in a base station to which the embodiment of the first channel allocation device of the present invention, which embodies the first channel allocation method of the present invention, is applied. .

FIG. 3 is an example of a channel state table stored in a computing unit in a base station to which an embodiment of the first channel allocation device of the present invention that embodies the first channel allocation method of the present invention is applied. FIG.

FIG. 4 is a flowchart of a channel allocation process executed in a base station to which an embodiment of the first channel allocation device of the present invention that embodies the first channel allocation method of the present invention is applied.

FIG. 5 is an example of a channel state table stored in a calculation unit in a base station to which an embodiment of a second channel allocation device of the present invention that embodies a second channel allocation method of the present invention is applied. FIG.

FIG. 6 is an example of a channel state table stored in a calculation unit in a base station to which an embodiment of a third channel allocation device of the present invention that embodies a third channel allocation method of the present invention is applied. FIG.

FIG. 7 is a diagram showing a configuration of a base station to which a conventional channel allocation method is applied.

FIG. 8 is a diagram showing a channel format when a control channel and a communication channel are set on the same carrier frequency.

FIG. 9 is a flowchart of a conventional channel allocation process.

FIG. 10 is a diagram showing a channel state table stored in a channel storage unit in a conventional base station.

[Explanation of symbols]

1 base station 2 Adaptive array antenna 3 Signal processing unit 4 Control signal receiver 5 computing section 6 channel selector 7 Control signal transmitter 8 Communication channel section 9 terminals 10, 11, 12, 13 Antenna element 14,15,16,17 Weight part 18 Synthesis Department 100 base stations 102 base station antenna 103 signal processor 104 control signal receiver 105 channel status storage 106 channel selection unit 107 control signal transmitter 108 communication channel section 120 control channels

Continuation of the front page (56) Reference JP 2000-106696 (JP, A) JP 8-265832 (JP, A) JP 9-215052 (JP, A) JP 10-70502 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04B ⁷ /24-7/26 H04Q ⁷ /00-7/36 H01Q 3/26

Claims (4)

(57) [Claims] 1. A channel allocation method in a communication control station comprising an antenna means capable of adaptively changing a beam pattern, wherein the communication request is made when a control signal desired to be communicated from a terminal is received. The spatial correlation value between the terminal and the other terminal in communication, by the communication data based on the received data obtained from the received control signal and the received data from the other terminal in communication A communication channel, which is calculated and whose spatial correlation value obtained by the calculation is reduced, is assigned to a terminal desiring to communicate, and a plurality of the spatial correlation values are provided in the antenna means.
Calculation using the signal correlation matrix between the antenna elements of
A channel allocation method characterized by being obtained by . 2. A channel allocation method in a communication control station comprising an antenna means capable of adaptively changing a beam pattern, wherein the communication request is made when a control signal desired to be communicated from a terminal is received. The signal-to-interference power ratio between the terminal and the other terminal in communication with each other, based on the received data obtained from the received control signal and the received data from the other terminal in communication. A channel allocating method characterized in that a communication channel is calculated and a communication channel is allocated to a terminal which desires the communication using the signal-to-interference power ratio obtained by the calculation. 3. A channel allocating device in a communication control station, comprising an antenna means capable of adaptively changing a beam pattern, wherein the communication request is made when a control signal desired by the terminal is received. To communicate a spatial correlation value in communication with another terminal in communication with the terminal based on the received data obtained from the received control signal and the received data from the other terminal in communication. And a channel selecting unit for allocating the communication channel obtained by the calculating unit and having a reduced spatial correlation value to the terminal desiring the communication , the calculating unit comprising: A plurality of antennas provided in the antenna means
By performing calculation using the signal correlation matrix between the tenor elements,
The channel allocation device is characterized in that the spatial correlation value is obtained . 4. A channel allocating device in a communication control station, comprising an antenna means capable of adaptively changing a beam pattern, wherein the communication request is made when a control signal desired for communication is received from a terminal. The signal-to-interference power ratio between the terminal and the other terminal in communication with each other, based on the received data obtained from the received control signal and the received data from the other terminal in communication. And a channel selection unit configured to allocate a communication channel to a terminal desiring the communication using the signal-to-interference power ratio obtained by the calculation unit. A channel allocating device characterized in that