JP4927622B2 - Base station, communication method and program - Google Patents

Description

  The present invention relates to a base station, a communication method, and a program that perform wireless communication using a time division multiple access method and a space division multiple access method.

  Conventionally, in wireless communication systems such as PHS, a time division multiple access (hereinafter referred to as TDMA / TDD) method and a space division multiple access (hereinafter referred to as SDMA) method are applied. ing.

  In the wireless communication system described above, the base station allocates all time slots for call connection (TCH (Traffic Channel)) with a plurality of terminal apparatuses, and there is no empty time slot, so that a new terminal apparatus is allocated. When a call connection request is received from the mobile station, one common time slot is allocated to two terminal devices already in wireless communication, and wireless communication is executed by the SDMA method. Then, the base station allocates an empty time slot provided by executing the SDMA method to a new terminal device.

  Here, in the base station, when performing wireless communication by the SDMA scheme, spatial multiplexing determination is performed in which the two terminal devices determine whether or not wireless communication is possible by the SDMA scheme (see, for example, Patent Document 1). . For example, in the spatial multiplexing determination disclosed in Patent Document 1, the base station acquires the dynamic range of uplink RSSI and the change speed of the reception response vector for each of two terminal devices, and based on the acquired information. And is configured to execute spatial multiplexing determination.

As a result, the base station can perform spatial multiplexing determination according to the reception quality and the movement status of the terminal device, so that it is possible to suppress the deterioration of the communication quality when performing wireless communication by the SDMA scheme.
JP 2002-58061 A

  However, in the above-described wireless communication system, when wireless communication is started by the SDMA method, the terminal device whose time slot is changed includes the frequency channel (frequency band) assigned in the time slot before the change, and the changed time slot. May be different from the frequency channel allocated in each time slot.

  At this time, if the frequency band of the allocated frequency channel is greatly different, the propagation path characteristic of the radio signal is changed, so that the communication quality may be deteriorated when the radio communication is executed by the SDMA method. That is, in the above-described wireless communication system, even if it is determined that wireless communication by the SDMA method is possible as a result of performing spatial multiplexing determination based on the wireless signal of the frequency channel assigned to each of the two terminal devices. When communication is started by the SDMA method, there is a problem that communication quality is deteriorated.

  Therefore, the present invention has been made in view of the above points, and in a wireless communication system that executes a time division multiple access (TDMA) method and a space division multiple access (SDMA) method, executes the space division multiple access method. It is an object of the present invention to provide a base station, a communication method, and a program that can suppress a decrease in communication quality when the communication is performed.

A first aspect of the present invention includes a plurality of frequency channels having different frequencies, among a plurality of time slots, free line communications assigned and one of said time slots and one said frequency channel to the terminal apparatus a base station, a receiving section for receiving the connection request information, the previous SL connection request information determines the slot determination unit whether there is an empty-out timeslots to be assigned to the transmitted end end device, If it is determined that there is no pre-Kisora-out timeslots, in other terminal devices in which the time slots and said frequency channels is allocated, smaller than the spacing frequency band available that frequency channel It is determined whether or not wireless communication by a spatial multiple access method can be performed between a selection unit that selects a plurality of other terminal devices within a predetermined range set in advance and the selected other terminal devices. Many A determination unit, according to the determination result of the multiplexing determining unit, and a time slot and frequency channel are assigned to any other terminal apparatus for performing wireless communication of spatial multiple access scheme, the spatial multiple access scheme And an allocating unit that allocates to a plurality of other terminal devices that execute wireless communication .

  According to this feature, in the base station, when there is no time slot to be allocated when new connection request information is received, the base station selects a plurality of other terminal apparatuses to which frequency channels whose frequency channel intervals are within a predetermined range are allocated. . In addition, the base station determines whether or not wireless communication by the spatial multiple access method can be executed with the selected plurality of other terminal devices, and one base station determines the number of other terminal devices according to the determination result. Wireless communication using the spatial multiple access method is performed by assigning a time slot and one frequency channel. In other words, since the base station selects a frequency channel having a frequency interval within a predetermined range and performs spatial multiplexing determination, when performing wireless communication by the spatial multiplexing connection method, one of the other terminal devices is Even if the frequency channel is changed to the frequency channel of the other terminal device, it is possible to prevent the frequency from being changed to a frequency channel far away. Therefore, when the spatial multiple access method is executed, it is possible to suppress the fluctuation of the propagation path characteristics of the terminal device whose time slot has been changed. Thus, according to such a base station, in a wireless communication system that executes a time division multiple access (TDMA) method and a space division multiple access (SDMA) method, communication quality when the space division multiple access method is executed. Can be suppressed.

  One feature of the present invention relates to the above-described feature, wherein when the connection request information is received, the slot determination unit assigns the time slot assigned to the other terminal device and the other terminal device. The time slot that is not assigned to the other terminal device, and the time slot that is not assigned to the other terminal device. If it is determined that there is a frequency channel, the frequency channel assigned to the other terminal device is assigned the frequency channel having the same frequency or a frequency closer to the terminal device that has transmitted the connection request information. It is a summary.

  According to this feature, when there are time slots assigned to other terminal devices and empty time slots, the base station has the same frequency or the same frequency as the frequency channel assigned to the other terminal devices. A closer frequency channel is allocated to the terminal device that transmitted the connection request information. Therefore, in the base station, when performing spatial multiplexing determination, it is possible to provide more terminal apparatuses to which frequency channels having frequencies within a predetermined range are allocated in advance.

In an aspect of the present invention, among the plurality of different frequency channels and a plurality of time slots of frequency, the base station free line communications assigned and one of said time slots and one said frequency channel to the terminal apparatus a communication method in a receiving step of receiving the connection request information, and the amount of free slots judgment step of judging whether there is a data time slot to be allocated before Symbol connection request information end terminal device that transmitted the , before if Kisora-out timeslots is determined not, in other terminal devices in which the time slots and said frequency channels is allocated, than the interval frequency band available in the frequency channel wireless communication according to spatial multiple access scheme between the other terminals in small preset predetermined range a selection step of selecting multiple, with the selected plurality of other terminal devices A multiplexing determining step but determines executable or not, depending on the determination result of the multiple determination step, time slots assigned to any other terminal apparatus for performing wireless communication of spatial multiple access scheme and peripheral And an assigning step of assigning the wave number channel to a plurality of other terminal devices that perform wireless communication of the spatial multiple access method .

Also, an aspect of the present invention, among the plurality of different frequency channels and a plurality of time slots of frequency, you free line communications assigned and one of said time slots and one said frequency channel to the terminal apparatus the base station, a receiving section for receiving the connection request information, the previous SL connection request information assigned to the transmitted end terminal apparatus to check-out determining whether or not the slot determination unit has timeslots, before Symbol If it is determined that no available timeslots is, among other terminal apparatus and the time slot and the frequency channel is allocated, a small pre-set than the interval frequency band available in the frequency channel a selection unit for selecting a plurality of other terminals in the predetermined range is, multi-format determines whether wireless communication is executable by the spatial multiple access method with a selected plurality of other terminal devices And parts, in accordance with the determination result of the multiplexing determining unit, and a timeslot and frequency channel are assigned to any other terminal apparatus for performing wireless communication of spatial multiple access scheme, the spatial multiple access scheme radio The present invention relates to a program that functions as an allocating unit that is allocated to a plurality of other terminal devices that perform communication .

  According to the characteristics of the present invention, in a wireless communication system that executes a time division multiple access (TDMA) method and a space division multiple access (SDMA) method, it is possible to suppress deterioration in communication quality when the space division multiple access method is executed. A base station, a communication method, and a program can be provided.

(Configuration of wireless communication system according to an embodiment of the present invention)
An embodiment of the present invention will be described. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic.

  First, a schematic configuration of a wireless communication system 1 according to an embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, the wireless communication system 1 according to the present embodiment includes terminal apparatuses 10_1 to 10_n and a base station 100. Note that the wireless communication system 1 includes, for example, an external device such as a network and a server connected to the base station 100, but in the present embodiment, a description of the external device is omitted. Further, the terminal devices 10_1 to 10_n are simply described as the terminal device 10 as appropriate.

  The base station 100 performs radio communication with the terminal device 10 by a time division multiple access (hereinafter referred to as TDMA / TDD) method adopted by PHS or the like. Here, in the present embodiment, the base station 100 will be described as performing wireless communication with the terminal device 10 using four uplink time slots and four downlink time slots. Also, one of the uplink time slots and one of the downlink time slots are allocated for a control channel (CCH), and the base station allocates the remaining three uplink and downlink time slots to the terminal device 10. Assume that wireless communication is performed with the terminal device 10. Note that the base station assigns a pair of uplink time slot and downlink time slot to the terminal device 10, but in the present embodiment, the pair of uplink time slot and downlink time slot is simply described as a time slot as appropriate.

  The base station 100 performs adaptive array control using a plurality of antenna elements, and uses the same frequency channel (frequency band) as the same by a space division multiple access (SDMA) method. Radio signals are transmitted / received to / from a plurality of terminal apparatuses 10_1 to 10_n using time slots.

  When the base station 100 receives a call connection request (connection request information) transmitted from the terminal device 10, the base station 100 allocates a time slot and a frequency channel to the terminal device 10 in accordance with the call connection request.

  Here, in this embodiment, the call connection refers to a TCH (Traffic Channel) used for voice communication, data communication, and the like. The call connection request indicates TCH establishment request information for the terminal device 10 to request the base station 100 to assign a new TCH (call connection).

  Note that the base station 100 basically performs wireless communication by the TDMA / TDD method, and when a call connection request is received from a new terminal apparatus 10, if there is no available time slot, the base station 100 has already performed wireless communication. It is configured to perform wireless communication by the SDMA method with a plurality of terminal devices 10 and to open time slots for new terminal devices 10.

  The terminal devices 10_1 to 10_n perform wireless communication with the base station 100.

The terminal devices 10_1 to 10_n according to the present embodiment are assumed to be mobile devices such as a mobile phone such as a PHS, a PDA (Personal Digital Assistant), and a notebook computer.

(Configuration of base station according to this embodiment)
Next, the configuration of base station 100 will be described. Hereinafter, portions related to the present invention will be mainly described. Therefore, it should be noted that the base station 100 may include a functional block (such as a power supply unit) that is essential for realizing the function as the base station and that is not illustrated or omitted. The base station 100 according to the present embodiment includes a radio communication unit 110 connected to an antenna, a radio signal processing unit 120, and a control unit 130.
The wireless communication unit 110 performs wireless processing such as down-conversion on the wireless signal received from the terminal device 10 via the antenna, and outputs the processed signal to the wireless signal processing unit 120. In addition, the wireless communication unit 110 performs wireless processing such as up-conversion on the signal input from the wireless signal processing unit 120 and transmits a wireless signal to the terminal device 10 via the antenna.

  The radio signal processing unit 120 is connected to the radio communication unit 110 and the control unit 130. In addition, the radio signal processing unit 120 causes the radio communication unit 110 to transmit a radio signal whose directivity is controlled, and performs adaptive array control that increases the sensitivity of the signal input from the radio communication unit 110. When the radio signal processing unit 120 executes adaptive array control, the base station 100 performs radio communication with a plurality of terminal apparatuses 10 using the same frequency channel in the same time slot by the SDMA method. Execute.

  The control unit 130 controls various functions in the base station 100. In addition, the control unit 130 controls the operation of the radio signal processing unit 120 such as switching between the TDMA / TDD method and the SDMA method.

(Configuration of control unit)
Next, the configuration of the control unit 130 will be specifically described with reference to FIG. As shown in FIG. 2, the control unit 130 includes a storage unit 131, a communication unit 132, a slot determination unit 133, an allocation unit 134, a channel detection unit 135, a selection unit 136, and a multiple determination unit 137. It has. Note that the control unit 130 includes a communication unit 132, a slot determination unit 133, an allocation unit 134, a channel detection unit 135, a selection unit 136, a multiplex unit, and a multiplexing unit according to a program installed in the base station 100 (computer). The determination unit 137 may function.

  The storage unit 131 is a storage device such as a hard disk. In addition, the storage unit 131 stores a time slot assigned to the terminal device 10 and a frequency channel assigned to the terminal device 10 in association with each other. Specifically, as illustrated in FIG. 3, the storage unit 131 includes time slot identification information for identifying a time slot, channel identification information for identifying a frequency channel, terminal identification information for identifying the terminal device 10, and a terminal device. 10 is stored in association with call connection identification information for identifying the call connection with. These pieces of information are stored by the assignment unit 134 described later.

  The communication unit 132 is connected to the wireless signal processing unit 120. Further, the communication unit 132 receives the call connection request transmitted from the terminal device 10 via the wireless signal processing unit 120. In the present embodiment, the communication unit 132 configures a reception unit that receives call connection request information indicating a new connection request from the terminal device 10.

  When the communication unit 132 receives a call connection request, the slot determination unit 133 determines whether there is a time slot to be assigned to the terminal device 10 that has transmitted the call connection request. When a call connection request is received, the slot determination unit 133 determines whether there are time slots allocated to other terminal apparatuses 10 and time slots not allocated to other terminal apparatuses 10. . Specifically, when a call connection request is received by the communication unit 132, the slot determination unit 133 refers to the storage unit 131 and determines whether there is an empty time slot that is not assigned to the terminal device 10. . If it is determined that there is an empty time slot, the slot determination unit 133 continues to determine whether all the time slots are empty time slots. Further, the slot determination unit 133 notifies the determination result to the allocation unit 134 and the selection unit 136.

  The channel detection unit 135 performs carrier sense of the radio signal transmitted from the terminal device 10. Specifically, the channel detection unit 135 measures the reception quality of the radio signal transmitted from the terminal device 10 for each frequency channel. The reception quality may be a reception level, a desired wave-to-interference wave ratio, or the like. Further, the channel detection unit 135 detects a frequency channel whose measured reception quality is equal to or higher than a threshold stored in advance as a frequency channel that can be used by the terminal device 10 and notifies the allocation unit 134 of the detection result.

  When the slot determination unit 133 determines that there is no free time slot to be assigned to the new terminal device 10, the selection unit 136, among other terminal devices to which time slots and frequency channels have already been assigned, A plurality of other terminal devices whose frequency channel intervals are within a predetermined range are selected. Specifically, the selection unit 136 refers to the storage unit 131 when the slot determination unit 133 determines that there is no time slot to be allocated to the new terminal device 10, and the terminal device 10 that has already performed wireless communication. Read the frequency channel assigned to. In addition, the selection unit 136 selects frequency channels whose frequency channel interval (frequency difference) is within a predetermined range (for example, a range where the difference in the number of channels is “10 ch”) among the read frequency channels. In addition to selection, two terminal apparatuses 10 to which the frequency channel is assigned are selected. For example, if “221ch” is assigned to the terminal device 10_1, “210ch” is assigned to the terminal device 10_2, and “221ch” is assigned to the terminal device 10_3, the selection unit 136 performs more frequency. The pair of the terminal device 10_1 and the terminal device 10_3 to which “221ch” having a small difference is assigned is selected preferentially, and the identification information of the selected terminal device 10 is notified to the multiplex determination unit 137. The selection unit 136 may be configured to select only a plurality of terminal devices 10 to which the same frequency channel is assigned, or to select a plurality of terminal devices 10 to which closer frequency channels are assigned. May be.

  The multiplexing determination unit 137 determines whether or not wireless communication by the SDMA method can be performed with a plurality of other terminal devices 10 selected by the selection unit 136. Specifically, when receiving the identification information of the two terminal devices 10 from the selection unit 136, the multiplex determination unit 137 determines whether or not the two terminal devices 10 can execute wireless communication by the SDMA scheme. . At this time, the multiplex determination unit 137 calculates values such as a reception level, a spatial correlation value, and a reception power ratio based on radio signals transmitted from the two terminal apparatuses 10, and stores these calculation results in advance. Whether or not wireless communication by the SDMA method can be executed is determined based on whether or not the threshold is greater than or equal to the threshold value. The multiple determination unit 137 notifies the determination result to the allocation unit 134.

  The assigning unit 134 assigns time slots and frequency channels to the terminal device 10. The assigning unit 134 associates the time slot identification information of the time slot assigned to the terminal device 10, the channel identification information of the frequency channel, the terminal identification information of the terminal device 10, and the call connection identification information of the call connection. And stored in the storage unit 131. In addition, the assigning unit 134 notifies the terminal device 10 of the assigned time slot and frequency channel via the communication unit 132. In addition, when the call connection request is received by the communication unit 132, the allocation unit 134 has different time slot allocation methods depending on whether there is an empty time slot or no empty time slot.

  First, a time slot allocation method when there is an empty time slot will be described. When the call connection request is received by the communication unit 132, the allocation unit 134 does not allocate all the time slots to any of the terminal devices 10 by the slot determination unit 133, and all the time slots are empty time slots. If it is determined, the channel detection unit 135 acquires a frequency channel that can be used by the terminal device 10 that has transmitted the call connection request in an empty time slot. Further, the assigning unit 134 selects a frequency channel that can be used in a plurality of time slots from the available frequency channels. Also, the assigning unit 134 assigns the selected frequency channel and one of the available time slots to the terminal device 10 that has transmitted the call connection request.

  Further, when a call connection request is received by the communication unit 132, the assigning unit 134 is assigned by the slot determining unit 133 to a time slot that has already been assigned to another terminal device 10 and to another terminal device 10. When it is determined that there is a time slot that has not been received, the channel detection unit 135 acquires a frequency channel that can be used by the terminal device 10 that has transmitted the call connection request in an empty time slot. In addition, the assigning unit 134 refers to the storage unit 131 and selects a frequency channel having the same frequency or a frequency closer to the frequency channel assigned to the other terminal device 10 from the available frequency channels. . Here, the frequency is closer, for example, when the frequency channel “40ch” is assigned in another terminal device 10 that is already performing wireless communication, the frequency is “39ch” closer to “40ch” or “41ch” is indicated. Also, the assigning unit 134 assigns the selected frequency channel and one of the available time slots to the terminal device 10 that has transmitted the call connection request.

  Next, a time slot allocation method when there is no empty time slot will be described. When the communication unit 132 receives a call connection request, the allocating unit 134 determines whether two other terminals that are already performing wireless communication according to the determination result of the multiplexing determination unit 137 if there is no available time slot. The device 10 is assigned one time slot and one frequency channel. Specifically, when the multiplex determination unit 137 determines that the two terminal devices 10 performing wireless communication can execute wireless communication by the SDMA method, the allocating unit 134 determines whether the two terminal devices 10 perform wireless communication. One time slot and one frequency channel are assigned to perform wireless communication by the SDMA method. At this time, the assigning unit 134 assigns the time slot assigned to one of the two terminal devices 10 and the frequency channel to the two terminal devices 10. The assigning unit 134 assigns one empty time slot provided by performing the SDMA wireless communication to the terminal apparatus 10 that has transmitted the call connection request.

(Operation of base station)
Next, the operation of the base station 100 configured as described above will be described with reference to FIG. Specifically, an operation when the base station 100 receives a call connection request from the terminal device 10 will be described.

  In step S <b> 11, in the base station 100, the communication unit 132 receives the call connection request transmitted from the terminal device 10. In step S12, when the call connection request is received by the communication unit 132, the slot determination unit 133 determines whether there is an empty time slot.

  In step S <b> 13, when the slot determination unit 133 determines that there is an empty time slot, the slot determination unit 133 determines whether or not the empty time slot is all the time slots that can be used in the base station 100. In the present embodiment, it is determined whether there are three empty time slots. The slot determination unit 133 notifies the determination result to the allocation unit 134 and the channel detection unit 135.

  In step S14, when the slot determination unit 133 determines that all time slots are empty time slots, the channel detection unit 135 can use the terminal device 10 that has transmitted the call connection request in an empty time slot. An appropriate frequency channel is detected, and the detection result is notified to the allocation unit 134. Upon receiving this notification, the allocation unit 134 selects a frequency channel that can be used in a plurality of time slots from the available frequency channels. For example, when the channel detection unit 135 notifies the frequency channel as shown in FIG. 5A as a usable frequency channel, the allocating unit 134 selects 39CH or 221CH usable in the time slots 1 to 3. select. Further, when the frequency channel as shown in FIG. 5B is notified, the allocation unit 134 can use “38CH” or “61CH” that can be used in time slots 1 and 2 and time slots 1 and 3. One of “221CH” is selected. The assigning unit 134 selects a frequency channel that can be used in as many time slots as possible.

  In step S15, when the slot determination unit 133 determines that there are empty time slots but not all the time slots are empty time slots, the channel detection unit 135 determines that the terminal device 10 that transmitted the call connection request A frequency channel that can be used in an empty time slot is detected, and the detection result is notified to the allocation unit 134. Upon receiving this notification, the assigning unit 134 refers to the storage unit 131, and from among the available frequency channels, is the same as or closer to the frequency channel assigned to the terminal device 10 that is already performing wireless communication. Select a frequency channel.

  In step S <b> 16, the assigning unit 134 assigns the selected frequency channel and an empty time slot in which the frequency channel is detected to the terminal device 10 that has transmitted the call connection request, and stores it in the storage unit 131. The assignment unit 134 notifies the assigned time slot and frequency channel to the terminal device 10 that has transmitted the call connection request via the communication unit 132.

  In step S21, when it is determined that there is no empty time slot, the slot determination unit 133 notifies the selection unit 136 and the multiple determination unit 137 of the determination result. Upon receiving this notification, the selection unit 136 refers to the storage unit 131 and selects two terminal apparatuses 10 to which frequency channels having a frequency within a predetermined range are assigned. Further, the selection unit 136 notifies the multiple determination unit 137 of the two selected terminal devices 10 as one set. Note that when a plurality of sets of the terminal device 10 can be selected, the selection unit 136 notifies the multiple determination unit 137 of each of the selected plurality of sets.

  In step S <b> 22, the multiplex determination unit 137 performs spatial multiplex determination that determines whether wireless communication is possible by the spatial multiplex connection method in the notified set of two terminal devices.

  In step S <b> 23, as a result of performing the spatial multiplexing determination, the multiplexing determination unit 137 notifies the allocation unit 134 of the two terminal devices 10 when there is a set of terminal devices 10 capable of wireless communication by the spatial multiplexing connection method.

  In step S24, the multiplex determination unit 137 performs the spatial multiplex determination, and as a result, when there is no set of the terminal devices 10 capable of wireless communication by the spatial multiplex connection method, all of the stored information is stored with reference to the storage unit 131. The spatial multiplexing determination is performed on the terminal device 10.

  In step S <b> 25, when there is a set of terminal apparatuses 10 that can perform wireless communication by the spatial multiplexing connection method as a result of performing the spatial multiplexing determination, the multiplexing determination unit 137 notifies the allocation unit 134 of the combination of the terminal apparatuses 10. .

  In step S26, when the assignment unit 134 is notified of the set of the terminal devices 10 from the multiplex determination unit 137, the assignment unit 134 executes the wireless communication by the spatial multiplex connection method, and accordingly, the time slot assigned to each terminal device 10 and One of the time slots and frequency channels is selected from the frequency channels. Also, the assigning unit 134 assigns the selected one time slot and frequency channel to the two terminal devices 10 and sets the other time slot to an empty time slot.

  In step S27, the assigning unit 134 assigns the set empty time slot and frequency channel to the call connection with the terminal device 10 that has transmitted the call connection request. At this time, the frequency channel allocated by the allocation unit 134 is detected by the channel detection unit 135.

  In step S28, as a result of performing the spatial multiplexing determination on all existing terminal devices 10, the multiplexing determination unit 137 determines that there is no set of terminal devices 10 capable of wireless communication by the spatial multiplexing connection method. A call connection failure notification indicating that the connection cannot be received is transmitted to the terminal device 10 that has transmitted the call connection request via the communication unit 132.

(Operations of base station and terminal device when a call connection request is received when there is an empty time slot)
Next, operations of the base station 100 and the terminal device 10 that have received a call connection request when there is an empty time slot will be described with reference to the sequence diagram of FIG. Here, description will be made on the assumption that the base station 100 has not yet communicated with the terminal device 10 and all the time slots are empty time slots.

  In step S110, the terminal apparatus 10_1 transmits a TCH establishment request for requesting call connection to the base station 100, and the base station 100 receives the request.

  In step S120, the base station 100 determines that all the time slots are empty, and detects a frequency channel that can be used by the terminal apparatus 10_1 that has transmitted the call connection request in the empty time slots. Further, the base station 100 selects a frequency channel that can be used in a plurality of time slots from the available frequency channels.

  In step S130, the base station 100 notifies the terminal device 10_1 of the selected frequency channel and an empty time slot, and starts call connection communication with the terminal device 10_1.

  In step S140, the terminal apparatus 10_2 transmits a TCH establishment request for requesting call connection to the base station 100, and the base station 100 receives the request.

  In step S150, the base station 100 determines that there are empty slots but not all empty time slots, and detects frequency channels that can be used in the empty time slots in the terminal device 10_2 that has transmitted the call connection request. To do. In addition, the base station 100 selects a frequency channel that is the same as or close to the frequency channel allocated to the terminal device 10_1 from the available frequency channels.

  In step S160, the base station 100 notifies the terminal device 10_2 of the selected frequency channel and an empty time slot, and starts call connection communication with the terminal device 10_2.

  In step S170, the terminal apparatus 10_3 transmits a TCH establishment request for requesting call connection to the base station 100, and the base station 100 receives the request.

  In step S180, the base station 100 determines that there are empty slots but not all empty time slots, and the terminal device 10_3 that has transmitted the call connection request detects a frequency channel that can be used in the empty time slots. To do. Further, the base station 100 selects a frequency channel that is the same as or close to the frequency channel allocated to the terminal devices 10_1 to 10_2 from the available frequency channels.

  In step S190, the base station 100 notifies the terminal device 10_3 of the selected frequency channel and an empty time slot, and starts call connection communication with the terminal device 10_3.

  In this way, when there is an empty time slot, the base station 100 allocates a frequency channel and an empty time slot to the terminal device 10 that has transmitted the call connection request.

(Operations of base station and terminal device when a call connection request is received when there is no empty time slot)
Next, operations of the base station 100 and the terminal device 10 that have received a call connection request when there is no empty time slot will be described with reference to the sequence diagram of FIG. Here, description will be made on the assumption that the base station 100 is performing wireless communication with the terminal devices 10_1 to 10_3 and there is no empty time slot.

  In step S210, the terminal apparatus 10_4 transmits a TCH establishment request for requesting a call connection to the base station 100, and the base station 100 receives the request.

  In step S220, the base station 100 determines that there is no empty time slot, and selects two terminal devices 10 to which frequency channels having a frequency within a predetermined range are allocated among the terminal devices 10_1 to 10_3. . In addition, the base station 100 performs spatial multiplexing determination on the two selected terminal devices 10 and determines whether the two selected terminal devices 10 can perform wireless communication by the spatial multiplexing connection method. Here, the frequency channel “221ch” of the terminal device 10_1 and the frequency channel “221ch” of the terminal device 10_3 are selected. Further, the base station 100 will be described below assuming that each terminal apparatus 10 determines that wireless communication is possible by the spatial multiple access method.

  In step S230, the base station 100 instructs the terminal device 10_3 to switch to the time slot and the frequency channel assigned to the terminal device 10_1. Here, since the frequency channels assigned to the terminal device 10_1 and the terminal device 10_3 are the same “221ch” and are not changed, only the switching of the time slot may be instructed.

  In step S240, the base station 100 assigns the time slot originally assigned to the terminal device 10_3 to the terminal device 10_4 as an empty time slot. Further, the base station 100 notifies the terminal device 10_4 of the allocated time slot and the frequency channel.

  In this way, the base station 100 uses, for the call connection of the new terminal apparatus 10_4, an empty time slot provided by executing the spatial multiplexing connection method in response to a call connection request from the new terminal apparatus 10_4. assign.

(Operations and effects of the wireless communication system according to the present embodiment)
According to the wireless communication system 1 according to the present embodiment, when there is no time slot to be assigned when the base station 100 receives the connection request information, the base station 100 assigns another terminal to which a frequency channel having a frequency difference within a predetermined range is assigned. Multiple devices 10 are selected. In addition, the base station 100 determines whether or not wireless communication using the SDMA method can be performed with a plurality of other selected terminal apparatuses 10, and performs wireless communication using the SDMA method according to the determination result. That is, since the base station 100 selects a frequency channel having a frequency difference within a predetermined range and performs spatial multiplexing determination, when performing wireless communication by the SDMA scheme, any one of a plurality of terminal devices 10 (for example, Even if the terminal device 10_3) is changed to the frequency channel of the other terminal device (for example, the terminal device 10_1), the frequency channel can be prevented from being changed to a frequency channel far away. Therefore, when performing wireless communication using the SDMA scheme, it is possible to suppress a reduction in communication quality of the terminal device 10 due to a large fluctuation in the propagation path characteristics of the terminal device 10 whose time slot has been changed. As described above, according to the base station 100 according to the present embodiment, in the wireless communication system that executes the time division multiple access (TDMA) method and the space division multiple access (SDMA) method, communication when the SDMA method is executed. A reduction in quality can be suppressed.

(Other embodiments)
As described above, the content of the present invention has been disclosed through one embodiment of the present invention. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments will be apparent to those skilled in the art.

  For example, in the above-described embodiment, various functions included in the base station 100 illustrated in FIG. 2 may be arranged in an apparatus other than the base station 100. For example, these functions can be arranged in a server (not shown) that exists above the base station 100 in the wireless communication system 1. That is, the present invention can be applied to various apparatuses provided in a wireless communication system that performs communication by the SDMA method.

  As described above, the present invention naturally includes various embodiments that are not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

It is a schematic block diagram which shows the structure of the radio | wireless communications system which concerns on embodiment of this invention. It is a block block diagram of the control part in the base station which concerns on embodiment of this invention. It is a figure which shows the information memorize | stored in the memory | storage part which concerns on embodiment of this invention. It is a flowchart which shows operation | movement of the base station which concerns on embodiment of this invention. (A) It is a figure which shows an example of the frequency channel for every time slot detected by the base station which concerns on embodiment of this invention. (B) It is a figure which shows an example of the frequency channel for every time slot detected by the base station which concerns on embodiment of this invention. FIG. 7 is a sequence diagram showing operations of a base station and a terminal device in the wireless communication system according to the embodiment of the present invention. FIG. 7 is a sequence diagram showing operations of a base station and a terminal device in the wireless communication system according to the embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Wireless communication system, 10 ... Terminal device, 100 ... Base station, 110 ... Wireless communication part, 120 ... Wireless signal processing part, 130 ... Control part, 131 ... Memory | storage part, 132 ... Communication part, 133 ... Slot determination part, 134 ... allocation unit, 135 ... channel detection unit, 136 ... selection unit, 137 ... multiple determination unit, 1 to 3 ... time slot, S11 to S28 ... step, S110 to S190 ... step, S210 to S240 ... step,

Claims (4)

A plurality of frequency channels having different frequencies, among a plurality of time slots, and one of said time slots and one of the frequency channels to a base station you free line communications assigned to the terminal device,
A reception unit that receives a connection request information,
And determining slot determination unit whether there is an empty-out timeslots to be allocated to an end terminal device that has transmitted the previous SL connection request information,
If it is determined that there is no pre-Kisora-out timeslots, in other terminal devices in which the time slots and said frequency channels is allocated, smaller than the spacing frequency band available that frequency channel A selection unit for selecting a plurality of other terminal devices within a predetermined range set in advance ;
A multiplex determination unit that determines whether or not wireless communication by the spatial multiple access method can be executed with the selected other terminal devices;
According to the determination result of the multiplexing determining unit, and a time slot and frequency channel are assigned to any other terminal apparatus for performing wireless communication of spatial multiple access scheme, perform the radio communication of the spatial multiple access scheme An assigning unit to be assigned to a plurality of other terminal devices ,
A base station comprising: When the connection request information is received, the slot determination unit determines whether there is a time slot assigned to the other terminal device and a time slot not assigned to the other terminal device. And
The allocation unit is allocated to the other terminal device when it is determined that there is a time slot allocated to the other terminal device and a time slot not allocated to the other terminal device. The base station according to claim 1, wherein the frequency channel having a frequency closer to that of the frequency channel is allocated to the terminal device that has transmitted the connection request information. Among different from the plurality of frequency channels and a plurality of time slots of frequency, a communication method and one of the time slots and one of the frequency channels at the base station you free line communications assigned to the terminal device,
A receiving step of receiving the connection request information,
And determining slot determination step whether or not there is an empty-out timeslots to allocate before Symbol connection request information end terminal device that transmitted the,
If it is determined that there is no pre-Kisora-out timeslots, in other terminal devices in which the time slots and said frequency channels is allocated, smaller than the spacing frequency band available that frequency channel A selection step of selecting a plurality of other terminal devices within a predetermined range set in advance ;
Multiple determination step for determining whether or not wireless communication by the spatial multiple access method can be executed with the selected other terminal devices;
Depending on the determination result of the multiple determination step, a time slot and frequency channel are assigned to any other terminal apparatus for performing wireless communication of spatial multiple access scheme, perform the radio communication of the spatial multiple access scheme Assigning to a plurality of other terminal devices ,
A communication method comprising: Among different from the plurality of frequency channels and a plurality of time slots of frequency, one base station to you free line communications assigned to the terminal device and the time slot and one said frequency channel,
A reception unit that receives a connection request information,
And determining slot determination unit whether there is an empty-out timeslots to be allocated to an end terminal device that has transmitted the previous SL connection request information,
If it is determined that there is no pre-Kisora-out timeslots, in other terminal devices in which the time slots and said frequency channels is allocated, smaller than the spacing frequency band available that frequency channel A selection unit for selecting a plurality of other terminal devices within a predetermined range set in advance ;
A multiplex determination unit that determines whether or not wireless communication by the spatial multiple access method can be executed with the selected other terminal devices;
According to the determination result of the multiplexing determining unit, and a timeslot and frequency channel are assigned to any other terminal apparatus for performing wireless communication of spatial multiple access scheme, perform the radio communication of the spatial multiple access scheme An assigning unit to be assigned to a plurality of other terminal devices ,
A program characterized by making it function.

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