JP4970097B2 - COMMUNICATION METHOD AND BASE STATION DEVICE USING THE SAME - Google Patents

Description

  The present invention relates to communication technology, and more particularly, to a communication method for assigning a channel to a terminal device and a base station device using the communication method.

In soft combine, a plurality of base station apparatuses or sectors transmit the same voice and data at the same timing, and a terminal apparatus combines signals transmitted from the plurality of base station apparatuses or sectors. Such a soft combine has an advantage that the ratio of actual voice and data to noise is larger than a method of selecting a sector having a good radio wave environment. Conventionally, an area for transmitting a flow for executing soft combine is determined, and the start and stop of the flow are controlled. Here, the base station apparatus collects information from a plurality of terminal apparatuses, and determines a base station apparatus to which communication information should be transmitted based on the information (see, for example, Patent Document 1).
JP 2006-13826 A

  When a base station apparatus allocates a resource, that is, a channel, to a terminal apparatus, if a free resource exists, the requested amount is allocated, but if there is no free resource, the allocation cannot be performed. On the other hand, if there is a terminal device that can communicate with a plurality of base station devices, such as a soft combine, there is also a terminal device that can communicate with only one base station device. Even if the base station apparatus does not assign a channel to the terminal apparatus such as the former, the terminal apparatus can execute communication with another base station apparatus. On the other hand, if the base station apparatus does not assign a channel to the latter terminal apparatus, the terminal apparatus cannot execute communication. In order to improve serviceability as a whole system, it is required to reduce the number of terminal devices that cannot communicate.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a communication technique that reduces the number of terminal devices that cannot communicate as a whole system.

  In order to solve the above-described problem, a base station apparatus according to an aspect of the present invention includes an acquisition unit that acquires information about a base station apparatus to which a terminal device can be connected, and a plurality of information based on the information acquired by the acquisition unit. A terminal device that gives priority to each terminal device such that a terminal device that is less likely to be connected to another base station device has a higher priority, and the priority given by the granting unit An allocating unit for allocating a channel to the communication unit, and a communication unit for communicating with the terminal device to which the allocating unit has allocated the channel.

  According to this aspect, since the channel is allocated to the terminal device according to the priority given based on the information on the base station device to which the terminal device can be connected, the base station device to which the terminal device can be connected can be considered, and the entire system As a result, the number of terminal devices that cannot communicate can be reduced.

  The communication unit receives a channel allocation request from a terminal device and includes a channel allocation request including information on a base station device to which the terminal device can be connected, and the acquisition unit receives a channel allocation request received from the communication unit. From the allocation request, information regarding the base station apparatus to which the terminal apparatus can be connected may be extracted. In this case, since information related to the base station apparatus to which the terminal device can be connected is received from the terminal device, accurate information can be used.

  The communication unit receives a channel allocation request from a terminal device and includes a channel allocation request including information for identifying a base station device to which the terminal device can be connected. Means for extracting information for identifying a base station device connectable to the terminal device from the channel allocation request received in step 1, and a base station to which the terminal device can be connected from the base station device included in the extracted information The information regarding the apparatus may include means for receiving information regarding channels that can be allocated by the base station apparatus. In this case, since the allocation request received from the terminal device only includes information for identifying a base station device to which the terminal device can be connected, the amount of information transmitted from the terminal device can be reduced.

  The information processing apparatus may further include a receiving unit that receives information on a channel that can be allocated by the base station device from another base station device, and a specifying unit that specifies a direction in which the other base station device receives the information in the receiving unit. . The communication unit accepts a channel assignment request from the terminal device, and the acquisition unit includes means for specifying the presence direction of the terminal device that has received the channel assignment request in the communication unit, the existence direction of the terminal device, and the specifying unit. The information processing apparatus may include means for generating information related to a base station apparatus to which the terminal apparatus can be connected based on the identified direction of the other base station apparatus and information received by the receiving unit. In this case, after estimating the presence direction of the terminal device, information on the base station device to which the terminal device can be connected is generated, so that the amount of information transmitted from the terminal device can be reduced.

  Another aspect of the present invention is a communication method. This method includes a step of acquiring information related to a base station device to which a terminal device can be connected, and a possibility of being able to connect to another base station device for each of a plurality of terminal devices based on the acquired information. There are provided a step of assigning a priority so that a lower terminal device becomes higher, a step of assigning a channel to the terminal device while referring to the assigned priority, and a step of communicating with the terminal device to which the channel is assigned.

  It should be noted that any combination of the above-described constituent elements and a conversion of the expression of the present invention between a method, an apparatus, a system, a recording medium, a computer program, etc. are also effective as an aspect of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the number of the terminal devices which cannot communicate as the whole system can be reduced.

  Before describing the present invention specifically, an outline will be given first. Embodiments of the present invention relate to a communication system including a base station device and at least one terminal device. In the communication system, each frame is formed by time-division multiplexing a plurality of time slots, and each time slot is formed by frequency-division multiplexing a plurality of subchannels. Each subchannel is formed by a multicarrier signal. Here, OFDM signals are used as multicarrier signals, and OFDMA (Orthogonal Frequency Division Multiple Access) is used as frequency division multiplexing. The OFDMA scheme is a technique for frequency multiplexing a plurality of terminal devices using OFDM.

  The base station apparatus performs communication with the plurality of terminal apparatuses by assigning each of the plurality of subchannels included in each time slot to the terminal apparatus. However, when there is no subchannel that can be allocated to the base station apparatus, the base station apparatus rejects subchannel allocation to the terminal apparatus. Such a terminal device cannot perform communication, and is in the same state as that outside the service area. On the other hand, the terminal device may exist at a position where it can communicate with a plurality of base station devices. Such a terminal device may be assigned a subchannel from another base station device even if the subchannel assignment is rejected from one base station device, and the probability that communication cannot be performed is also reduced. In order to improve serviceability as a whole system, it is desirable to reduce the number of terminal devices that cannot communicate. In order to cope with this, the communication system according to the present embodiment executes the following processing.

  Before executing communication, the terminal device receives a control signal broadcast from the base station device, and recognizes the presence of the base station device based on the information of the base station device included in the received control signal. To do. In addition, the control signal includes information related to an empty subchannel in the base station apparatus, and the terminal apparatus also acquires such information. The terminal device generates a table (hereinafter referred to as “resource information”) indicating the relationship between connectable base station devices and the number of free subchannels corresponding thereto. Further, the terminal device selects a predetermined base station device and transmits an allocation request to the selected base station device, but includes resource information in the allocation request. The base station apparatus that has received the allocation request gives priority to each terminal apparatus while referring to the resource information for each of the terminal apparatus and the already connected terminal apparatus. Here, the priority is given so as to increase as the terminal device is less likely to be connected to another base station device.

  If the base station apparatus has a free subchannel, the base station apparatus allocates the subchannel to the terminal apparatus that requests the allocation. On the other hand, if there is no free subchannel and a terminal device with a priority lower than the priority of the terminal device requesting allocation has already been connected, the base station device disconnects the terminal device with a lower priority. After that, a subchannel is allocated to a terminal apparatus that requests allocation. Note that an allocation request is transmitted to another base station apparatus that can be connected to a terminal apparatus having a low priority. Through the above processing, a terminal device that can preferentially assign subchannels to a terminal device that can be assigned subchannels only by the base station device, and can assign subchannels to other base station devices. On the other hand, the subchannel is released. However, a terminal apparatus whose subchannel is released in the base station apparatus can expect subchannel allocation in another base station apparatus. As a result, the terminal device can secure a subchannel in any of the base station devices.

  FIG. 1 shows a configuration of a communication system 100 according to an embodiment of the present invention. The communication system 100 includes a first terminal device 12a, a second terminal device 12b, and a third terminal device 12c, which are collectively referred to as a base station device 10 and a terminal device 12.

  The base station device 10 has a terminal device 12 connected to one end via a wireless network and a wired network (not shown) connected to the other end. Further, the terminal device 12 is connected to the base station device 10 via a wireless network. The base station apparatus 10 performs communication with the plurality of terminal apparatuses 12 by assigning communication channels to the plurality of terminal apparatuses 12. Specifically, the base station device 10 broadcasts a control signal, and the terminal device 12 recognizes the presence of the base station device 10 by receiving the control signal. Thereafter, the terminal apparatus 12 transmits a channel allocation request signal to the base station apparatus 10, and the base station apparatus 10 allocates a communication channel to the terminal apparatus 12 in response to the received request signal.

  In addition, the base station apparatus 10 transmits information on the communication channel assigned to the terminal apparatus 12, and the terminal apparatus 12 performs communication with the base station apparatus 10 while using the assigned communication channel. As a result, the data transmitted from the terminal device 12 is output to the wired network via the base station device 10 and finally received by a communication device (not shown) connected to the wired network. Data is also transmitted in the direction from the communication device to the terminal device 12. 1 shows one base station apparatus 10, the communication system 100 may include a plurality of base station apparatuses 10, and the terminal apparatus 12 communicates with one of the base station apparatuses 10. If a channel is assigned, communication can be executed. Whether or not the terminal device 12 can communicate with the base station device 10 generally depends on the relative positional relationship between the base station device 10 and the terminal device 12.

  In the above description, the communication channel is specified by the combination of the subchannel and the time slot described above. In addition, since the base station apparatus 10 has a plurality of time slots and a plurality of subchannels, the base station apparatus 10 executes OFDMA using a plurality of subchannels while executing TDMA using the plurality of time slots.

  2A to 2C show a frame configuration in the communication system 100. FIG. The horizontal direction in the figure corresponds to the time axis. A frame is formed by time multiplexing of eight time slots. The eight time slots are composed of four upstream time slots and four downstream time slots. Here, four uplink time slots are indicated as “first uplink time slot” to “fourth uplink time slot”, and four downlink time slots are indicated as “first downlink time slot” to “fourth downlink time slot”. . Further, the illustrated frame is repeated continuously.

  The configuration of the frame is not limited to that shown in FIG. 2A. For example, the frame configuration may be configured by four time slots or 16 time slots. The configuration will be described with reference to FIG. For the sake of brevity, it is assumed that the upstream time slot and the downstream time slot have the same configuration. For this reason, only one of the uplink time slot and the downlink time slot may be described, but the same description is valid for the other time slot. Furthermore, a super frame is formed by continuing a plurality of frames shown in FIG. Here, as an example, it is assumed that a super frame is formed by “20” frames.

  FIG. 2B shows the configuration of one time slot in FIG. The vertical direction in the figure corresponds to the frequency axis. As illustrated, one time slot is formed by frequency multiplexing of “16” subchannels from “first subchannel” to “16th subchannel”. In addition, the plurality of subchannels are frequency division multiplexed. Since each time slot is configured as shown in FIG. 2B, the above-described communication channel is specified by the combination of the time slot and the subchannel. Also, the frame configuration corresponding to one subchannel in FIG. 2B may be as shown in FIG. Note that the number of subchannels arranged in one time slot may not be “16”. Here, it is assumed that the allocation of the subchannel in the uplink time slot and the allocation of the subchannel in the downlink time slot are the same. Further, it is assumed that at least one control signal is assigned in units of superframes. For example, a control signal is assigned to one subchannel of one time slot among a plurality of downlink time slots included in a superframe. The same applies to the uplink.

  FIG. 2 (c) shows the configuration of one subchannel in FIG. 2 (b). Similar to FIG. 2A and FIG. 2B, the horizontal direction in the figure corresponds to the time axis, and the vertical direction in the figure corresponds to the frequency axis. Further, numbers “1” to “29” are assigned to the frequency axis, and these indicate subcarrier numbers. In this way, the subchannel is composed of multicarrier signals, and in particular is composed of OFDM signals. “TS” in the figure corresponds to a training symbol and is constituted by a known value. Further, it is assumed that a control signal may be included in “TS”. “GS” corresponds to a guard symbol, and no substantial signal is arranged here. “PS” corresponds to a pilot symbol, and is configured by a known value. “DS” corresponds to a data symbol and is data to be transmitted. “GT” corresponds to a guard time, and no substantial signal is arranged here.

  FIG. 3 shows an arrangement of subchannels in the communication system 100. In FIG. 3, the frequency axis is shown on the horizontal axis, and the spectrum for the time slot shown in FIG. 2B is shown. As described above, 16 subchannels from the first subchannel to the 16th subchannel are frequency division multiplexed in one time slot. Each subchannel is configured by a multicarrier signal, here, an OFDM signal.

  FIG. 4 shows the configuration of the terminal device 12. The terminal device 12 includes an RF unit 50, a modem unit 52, an IF unit 54, a radio control unit 56, and a storage unit 58.

  As a reception process, the RF unit 50 performs frequency conversion on a radio frequency multicarrier signal received from a base station apparatus 10 (not shown) to generate a baseband multicarrier signal. Here, the multicarrier signal is formed as shown in FIG. 3, and corresponds to the downlink time slot of FIG. Further, the RF unit 50 outputs a baseband multicarrier signal to the modem unit 52. In general, a baseband multicarrier signal is formed by an in-phase component and a quadrature component, and therefore should be transmitted by two signal lines. For the sake of clarity, a single signal line is used here. Only. The RF unit 50 also includes an AGC and an A / D conversion unit.

  As the transmission processing, the RF unit 50 performs frequency conversion on the baseband multicarrier signal input from the modem unit 52 to generate a radio frequency multicarrier signal. Further, the RF unit 50 transmits a radio frequency multicarrier signal. The RF unit 50 transmits a multicarrier signal while using the same radio frequency band as the received multicarrier signal. That is, as shown in FIG. 2A, TDD (Time Division Duplex) is used. The RF unit 50 also includes a PA (Power Amplifier) and a D / A conversion unit.

  The modem unit 52 demodulates the frequency domain multicarrier signal from the RF unit 50 as a reception process. The multicarrier signal converted into the frequency domain has components corresponding to each of the plurality of subcarriers as shown in FIGS. Demodulation is performed in units of subcarriers. The modem unit 52 outputs the demodulated signal to the IF unit 54. Further, the modem unit 52 performs modulation as transmission processing. The modem unit 52 outputs the modulated signal to the RF unit 50 as a multi-carrier signal in the frequency domain. As reception processing, the IF unit 54 receives the demodulation result from the modem unit 52 and outputs the demodulation result to a display or a speaker (not shown). The IF unit 54 inputs data from a button or a microphone (not shown) as a transmission process. The IF unit 54 assigns data to the subchannel. The IF unit 26 outputs the multicarrier signal to the modem unit 52.

  The wireless control unit 56 controls the operation of the IF unit 54 from the RF unit 50. Before executing communication with the base station apparatus 10, the radio control unit 56 receives a control signal transmitted from each base station apparatus 10. As described above, the control signal is assigned to one subchannel of one time slot among a plurality of downlink time slots included in the superframe. In addition, the control signal includes information such as the identification number of the base station apparatus 10 that has transmitted the control signal, the status of an empty subchannel in the base station apparatus 10, and the like. An example of the situation of free subchannels is the number of free subchannels. The wireless control unit 56 stores the acquired information in the storage unit 58. Here, when storing the information, the radio control unit 56 creates the above-described resource information in a table format. The resource information can be said to be information related to a base station apparatus to which the terminal apparatus 12 can be connected.

  FIG. 5 shows the data structure of the table stored in the storage unit 58. As illustrated, a base station apparatus ID column 200 and an empty subchannel number column 202 are included. In the resource information, the identification number of the base station device 10 and the number of free channels are associated with each other. Returning to FIG. The radio control unit 56 selects the base station apparatus 10 that should request the allocation of the subchannel while referring to the resource information. For example, the radio control unit 56 selects the base station apparatus 10 having a large number of free subchannels. The storage unit 58 also stores reception power when a control signal is received, and the radio control unit 56 may select the base station apparatus 10 corresponding to the control signal with large reception power.

  The radio control unit 56 transmits an allocation request to the selected base station apparatus 10 via the modem unit 52 and the RF unit 50. At that time, the radio control unit 56 includes resource information in the allocation request. Further, the radio control unit 56 receives a response from the base station apparatus 10 via the RF unit 50 and the modem unit 52. Since the response includes information on the assigned time slot and subchannel, the radio control unit 56 performs a communication operation from the RF unit 50 to the IF unit 54 in the assigned time slot and subchannel. Let On the other hand, the radio control unit 56 may receive a rejection instead of a response. At that time, the radio control unit 56 selects another base station apparatus 10 while referring to the resource information, and transmits an allocation request to the selected other base station apparatus 10.

  FIG. 6 shows the configuration of the base station apparatus 10. The base station apparatus 10 includes a first RF unit 20a, a second RF unit 20b, an NRF unit 20n, a baseband processing unit 22, a modem unit 24, an IF unit 26, a radio control unit 28, and a storage unit 30. including. The radio control unit 28 includes a control channel determination unit 32 and a radio resource allocation unit 38.

  Since the RF unit 20 performs the same processing as the RF unit 50 in FIG. 4, description thereof is omitted here. The baseband processing unit 22 inputs a baseband multicarrier signal from each of the plurality of RF units 20 as a reception operation. Since the baseband multi-carrier signal is a time domain signal, the baseband processing unit 22 converts the time domain signal to the frequency domain by FFT and performs adaptive array signal processing on the frequency domain signal. To do. Further, the baseband processing unit 22 executes timing synchronization, that is, FFT window setting, and also deletes the guard interval. Since a known technique may be used for timing synchronization and the like, description thereof is omitted here. The baseband processing unit 22 outputs the result of adaptive array signal processing to the modem unit 24. As a transmission operation, the baseband processing unit 22 receives a multi-carrier signal in the frequency domain from the modulation / demodulation unit 24 and performs dispersion processing using weight vectors.

  As a transmission operation, the baseband processing unit 22 converts the frequency domain signal to the time domain by IFFT on the frequency domain multicarrier signal input from the modem unit 24, and converts the converted time domain signal to the RF unit. 20 output. The baseband processing unit 22 also adds a guard interval, but the description is omitted here. Here, the frequency domain signal includes a plurality of subchannels as shown in FIG. 2B, and each of the subchannels includes a plurality of subcarriers as in the vertical direction of FIG. 2C. For the sake of clarity, it is assumed that the signals in the frequency domain are arranged in the order of subcarrier numbers to form a serial signal.

  Since the modem unit 24 performs the same processing as the modem unit 52 in FIG. 4, description thereof is omitted here. The IF unit 26 receives the demodulation result from the modulation / demodulation unit 24 as a reception process, and separates the demodulation result for each terminal device 12. That is, the demodulation result is composed of a plurality of subchannels as shown in FIG. Therefore, when one subchannel is assigned to one terminal apparatus 12, the demodulation result includes signals from a plurality of terminal apparatuses 12. The IF unit 26 separates such a demodulation result for each terminal device 12. The IF unit 26 outputs the separated demodulation result to a wired network (not shown). At that time, the IF unit 26 performs transmission according to information for identifying the destination, for example, an IP (Internet Protocol) address.

  Further, the IF unit 26 inputs data for the plurality of terminal devices 12 from a wired network (not shown) as a transmission process. The IF unit 26 assigns data to subchannels and forms a multicarrier signal from a plurality of subchannels. That is, the IF unit 26 forms a multicarrier signal composed of a plurality of subchannels as shown in FIG. The subchannel to which data is to be assigned is determined in advance as shown in FIG. 2 (c), and an instruction related thereto is received from the radio control unit 28. The IF unit 26 outputs the multicarrier signal to the modem unit 24.

  The wireless control unit 28 notifies the control signal described above from the modem unit 24 via the RF unit 20. Here, the control signal includes information about its own identification number and the number of empty subchannels. The control signal is assigned to a subchannel determined by a control channel determination unit 32 described later. The radio resource allocation unit 38 receives a subchannel allocation request from the terminal device 12 (not shown) from the RF unit 20 via the modem unit 24. Further, the allocation request includes information related to a base station apparatus to which the terminal apparatus 12 can be connected, that is, resource information. The radio resource allocation unit 38 acquires information on the base station apparatus to which the terminal apparatus 12 can be connected by extracting resource information from the received allocation request. Further, the radio resource allocation unit 38 stores the acquired resource information in the storage unit 30.

  The radio resource allocation unit 38 assigns a priority to each of the plurality of terminal devices 12 based on the acquired resource information and the resource information of the terminal device 12 that has already been assigned a subchannel. Here, the resource information of the terminal device 12 to which the subchannel has already been assigned is stored in the storage unit 30. The radio resource allocation unit 38 assigns a priority order such that the terminal device 12 that is less likely to be connected to another base station device 10 has a higher priority. That is, the number of base station devices 10 included in the resource information is calculated for each terminal device 12, and the highest priority “1” is given to the terminal device 12 with the smallest number. When there are a plurality of terminal devices 12 having the same number of base station devices 10, the radio resource allocation unit 38 increases the priority order of the terminal devices 12 with the earlier transmission time of the allocation request. Moreover, the radio | wireless resource allocation part 38 may give the priority which becomes high, so that the number of empty subchannels is totaled per terminal device 12 and a total value is small. The priority is given when an allocation request from a new terminal device 12 is received.

  The radio resource allocation unit 38 allocates a subchannel to the terminal device 12 while referring to the assigned priority order. That is, when the number of subchannels to be allocated is larger than the number of defined subchannels, the radio resource allocation unit 38 releases the terminal device 12 having a low priority. As a result, in the above situation, if the priority of the terminal apparatus 12 that has newly accepted the allocation request is lower than the priority order of the other terminal apparatuses 12, the radio resource allocation unit 38 has newly accepted the allocation request. The terminal device 12 is rejected from subchannel allocation. On the other hand, if there is a terminal apparatus 12 having a lower priority than the priority order of the terminal apparatus 12 that has newly accepted the allocation request, the radio resource allocation unit 38 releases the subchannel of the terminal apparatus 12.

  The radio resource allocation unit 38 allocates a subchannel to the terminal apparatus 12 that has newly received an allocation request. At that time, the radio resource allocating unit 38 transmits a response from the modem unit 24 to the terminal device 12 via the RF unit 20. The response includes information on the assigned subchannel and time slot. If the number of subchannels to be allocated is not greater than the number of defined subchannels, the radio resource allocation unit 38 allocates the subchannels as they are to the radio resource allocation unit 38 that has newly accepted the allocation request. The radio resource assignment unit 38 causes the RF unit 20 to cause the modem unit 24 to execute communication with the terminal device 12 to which the subchannel is assigned.

  The control channel determination unit 32 assigns control signals to subchannels. Here, the control signal is a signal including information used for controlling communication with the terminal device 12 as described above. Such a control signal is more important than a data signal. The control channel determination unit 32 selects a control signal for a predetermined subchannel while referring to the storage unit 30. In addition, the control channel determination unit 32 notifies the radio resource allocation unit 38 of the selected subchannel. The radio resource allocation unit 38 allocates a subchannel to the control signal according to the notification from the control channel determination unit 32. The storage unit 30 stores necessary data in cooperation with the wireless control unit 28 as described above.

  This configuration can be realized in terms of hardware by a CPU, memory, or other LSI of any computer, and in terms of software, it is realized by a program having a communication function loaded in the memory. Describes functional blocks realized by collaboration. Accordingly, those skilled in the art will understand that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.

  The operation of the communication system 100 configured as above will be described. FIG. 7 is a flowchart showing an assignment request transmission procedure in the terminal device 12. The RF unit 50 and the modem unit 52 receive the subchannel in which the control signal is arranged for the entire time (S10). All-time reception corresponds to a process of continuously receiving, rather than receiving only the timing of a specific time slot or subchannel. If even one control signal is received via the RF unit 50 and the modem unit 52 (Y in S12), the radio control unit 56 selects a connection destination from the base station apparatus 10 corresponding to the received control signal. (S14). Further, the radio control unit 56 transmits an allocation request including resource information to the selected base station apparatus 10 via the modem unit 52 and the RF unit 50 (S16). On the other hand, if no control signal is received via the RF unit 50 and the modem unit 52 (N in S12), the radio control unit 56 executes out-of-service processing (S18). Note that the out-of-service processing is a known technique, and thus description thereof is omitted here.

  FIG. 8 is a flowchart showing an allocation procedure in the base station apparatus 10. When receiving an allocation request from the RF unit 20 via the modem unit 24 (S40), the radio resource allocation unit 38 gives priority (S42). In consideration of the priority order, sub-channel allocation is possible (Y in S44), and if release is necessary (Y in S46), the radio resource allocation unit 38 passes the modulation / demodulation unit 24 through the RF unit 20 The disconnection is notified to the existing terminal device 12 (S48). On the other hand, if release is not necessary (N in S46), the radio resource allocation unit 38 skips step 48. Thereafter, the radio resource allocation unit 38 transmits a response from the modem unit 24 via the RF unit 20 (S50). If the sub-channel allocation is not possible in consideration of the priority order (N in S44), the radio resource allocation unit 38 notifies the outside of service area from the modem unit 24 via the RF unit 20 (S52).

  Hereinafter, modifications of the present invention will be described. In the embodiment, the base station apparatus 10 broadcasts a control signal while including information on the number of free subchannels, and the terminal apparatus 12 generates resource information based on the received information. In addition, the terminal device 12 transmits an allocation request including the resource information, and the base station device 10 assigns priorities based on the received resource information. On the other hand, in the modification, the control signal broadcast from the base station apparatus 10 does not include information on the number of free subchannels. The terminal device 12 transmits an allocation request while including the identification number of the base station device 10 corresponding to the received control signal. The base station apparatus 10 performs inter-base station communication with other base station apparatuses 10 based on the identification number included in the received allocation request. As a result, the base station apparatus 10 acquires resource information of other base station apparatuses 10. Further, the base station apparatus 10 assigns priorities based on the resource information as in the embodiment.

  The communication system 100 according to the modification is the same type as in FIG. 1, the terminal apparatus 12 according to the modification is the same type as in FIG. 4, and the base station apparatus 10 according to the modification is the same as in FIG. Of the type. Therefore, here, the description will focus on differences from the embodiment. First, processing in the terminal device 12 will be described. Before executing communication with the base station apparatus 10, the radio control unit 56 receives a control signal transmitted from each base station apparatus 10. Further, the control signal includes the identification number of the base station apparatus 10 that has transmitted the control signal. The wireless control unit 56 stores the acquired identification number in the storage unit 58. The radio control unit 56 selects the base station apparatus 10 that should request subchannel allocation. The radio control unit 56 transmits an allocation request to the selected base station apparatus 10 via the modem unit 52 and the RF unit 50. At that time, the wireless control unit 56 includes a list of identification numbers in the allocation request.

  Next, the operation in the base station apparatus 10 will be described. The radio resource allocation unit 38 notifies the control signal described above from the modem unit 24 via the RF unit 20. Here, the control signal includes its own identification number. The radio resource allocation unit 38 receives a subchannel allocation request from the terminal device 12 (not shown) from the RF unit 20 via the modem unit 24. Further, the allocation request includes an identification number of the base station apparatus 10 to which the terminal apparatus 12 can be connected. The radio resource allocation unit 38 extracts the identification number of the base station apparatus to which the terminal apparatus 12 is connectable from the received subchannel allocation request. The radio resource allocation unit 38 specifies the base station apparatus 10 to be accessed based on the identification number of the base station apparatus 10. The radio resource allocation unit 38 requests the specified base station apparatus 10 to transmit information on the number of free subchannels from the modem unit 24 via the RF unit 20.

  Further, the radio resource allocation unit 38 receives information on the number of free subchannels from the RF unit 20 via the modem unit 24. That is, the radio resource allocation unit 38 receives the number of subchannels that can be allocated by the base station apparatus 10 as information related to the base station apparatus 10 to which the terminal apparatus 12 can be connected, from the extracted identification number of the base station apparatus 10. In order to execute communication of such information, the base station apparatus 10 may have the specified base station apparatus 10 assign a subchannel. In that case, this base station apparatus 10 operate | moves like the terminal device 12 with respect to the specified base station apparatus 10. FIG. The specified request to the base station apparatus 10 may be made via the IF unit 26 and a wired network (not shown). The radio resource allocation unit 38 generates the resource information in the embodiment by associating the received information with the identification number of the base station apparatus 10 that has already been received. Since the subsequent processing is the same as that of the embodiment, the description is omitted here.

  FIG. 9 is a flowchart showing an assignment request transmission procedure in the terminal apparatus 12 according to the modification of the present invention. The RF unit 50 and the modem unit 52 receive the subchannel in which the control signal is arranged for the entire time (S70). If even one control signal is received via the RF unit 50 and the modem unit 52 (Y in S72), the radio control unit 56 selects a connection destination from the base station apparatus 10 corresponding to the received control signal. (S74). Further, the radio control unit 56 transmits an allocation request including the identification number of the connectable base station device 10 to the selected base station device 10 via the modem unit 52 and the RF unit 50 (S76). On the other hand, if the control signal is not received via the RF unit 50 and the modem unit 52 (N in 72), the radio control unit 56 executes out-of-service processing (S78).

  FIG. 10 is a flowchart showing an allocation procedure in the base station apparatus 10 according to the modification of the present invention. The radio resource allocation unit 38 receives an allocation request from the RF unit 20 via the modem unit 24 (S100). When the identification number of the base station apparatus 10 included in the allocation request is extracted, the radio resource allocation unit 38 transmits a sub-assignable sub-group from the modem unit 24 to the base station apparatus 10 having the extracted identification number via the RF unit 20. Request information about a channel. After that, the radio resource allocation unit 38 receives information on subchannels that can be allocated, for example, information on the number of free subchannels, from the other base station apparatus 10 via the modulation / demodulation unit 24 from the RF unit 20 (S102). In addition, the radio resource allocation unit 38 assigns priorities (S104).

  In consideration of the priority order, sub-channel allocation is possible (Y in S106), and if release is necessary (Y in S108), the radio resource allocation unit 38 passes the modulation / demodulation unit 24 through the RF unit 20 The disconnection is notified to the existing terminal device 12 (S110). On the other hand, if release is not necessary (N in S108), the radio resource allocation unit 38 skips Step 110. Thereafter, the radio resource allocation unit 38 transmits a response from the modem unit 24 via the RF unit 20 (S112). If the sub-channel allocation is not possible in consideration of the priority order (N in S106), the radio resource allocation unit 38 notifies the outside of the service area from the modem unit 24 via the RF unit 20 (S114).

  Hereinafter, another modification of the present invention will be described. In another modification, the base station apparatus 10 estimates the direction in which the terminal apparatus 12 exists by performing arrival direction estimation with respect to the allocation request. On the other hand, the base station apparatus 10 has previously received information on the number of empty subchannels in the other base station apparatus 10 from the other base station apparatus 10, and the direction in which the other base station apparatus 10 exists together with the information. Also estimate. Furthermore, the base station apparatus 10 identifies the base station apparatus 10 with which the terminal apparatus 12 can communicate from the direction in which the terminal apparatus 12 exists and the direction in which the other base station apparatus 10 exists. As a result, the base station device 10 generates resource information related to the terminal device 12.

  A communication system 100 according to another modification is the same type as that in FIG. 1, and a terminal apparatus 12 according to another modification is the same type as that in FIG. 4, and a base station apparatus 10 according to another modification. Is the same type as in FIG. Therefore, here, the description will focus on differences from the embodiment. First, processing in the terminal device 12 will be described. Before executing communication with the base station apparatus 10, the radio control unit 56 receives a control signal transmitted from each base station apparatus 10. The radio control unit 56 selects the base station apparatus 10 that should request subchannel allocation. The radio control unit 56 transmits an allocation request to the selected base station apparatus 10 via the modem unit 52 and the RF unit 50.

  Next, the operation in the base station apparatus 10 will be described. The radio resource allocation unit 38 notifies the control signal described above from the modem unit 24 via the RF unit 20. Further, the radio resource allocation unit 38 performs communication with the other base station device 10 via the modulation / demodulation unit 24 from the RF unit 20, thereby relating to subchannels to which the other base station device 10 can be allocated. Accept information, for example, information about the number of free subchannels. In addition, the baseband processing unit 22 performs direction-of-arrival estimation on signals from other base station apparatuses 10 and estimates directions in which the other base station apparatuses 10 exist. Since a known technique may be used for the arrival direction estimation, the description is omitted here. Further, the estimated direction is stored in the storage unit 30 while being associated with the number of empty subchannels.

  The radio resource allocation unit 38 receives a subchannel allocation request from the terminal device 12 (not shown) from the RF unit 20 via the modem unit 24. The baseband processing unit 22 performs direction-of-arrival estimation for the allocation request and estimates the direction in which the terminal device 12 exists. The radio resource allocating unit 38 refers to the existing direction of the other base station device 10 stored in the storage unit 30, and the other base station device existing in a certain range around the direction in which the terminal device 12 exists 10 is specified. In addition, the radio resource allocation unit 38 acquires the number of free subchannels corresponding to the other specified base station apparatus 10 from the storage unit 30. By executing such processing, the radio resource allocation unit 38 generates resource information. That is, the radio resource allocating unit 38 is a base station device to which the terminal device 12 can be connected based on the direction in which the terminal device 12 exists, the direction in which the other base station device 10 exists, and information on the number of free subchannels 10 is generated. Since the subsequent processing is the same as that of the embodiment, the description is omitted here.

  FIG. 11 is a flowchart showing an allocation procedure in the base station apparatus 10 according to another modification of the present invention. The radio resource allocation unit 38 receives an allocation request from the RF unit 20 via the modem unit 24 (S130). The baseband processing unit 22 estimates the direction of arrival of the terminal device 12 by estimating the arrival direction of the allocation request (S132). The radio resource allocation unit 38 assigns priorities based on the direction in which the terminal device 12 is present, the direction in which the base station device 10 has already been estimated, and the number of free subchannels in the base station device 10 that has already been received. (S134).

  In consideration of the priority order, subchannel allocation is possible (Y in S136), and if release is required (Y in S138), the radio resource allocation unit 38 transmits the modulation / demodulation unit 24 via the RF unit 20 The disconnection is notified to the existing terminal device 12 (S140). On the other hand, if release is not necessary (N in S138), the radio resource allocation unit 38 skips Step 140. Thereafter, the radio resource allocation unit 38 transmits a response from the modem unit 24 via the RF unit 20 (S142). If the sub-channel allocation is not possible in consideration of the priority order (N in S136), the radio resource allocation unit 38 notifies the outside of service area from the modem unit 24 via the RF unit 20 (S144).

  According to the embodiment of the present invention, the subchannels are allocated to the terminal devices according to the priority given based on the information on the base station devices to which the terminal devices can be connected. As a whole system, the number of terminal devices that cannot communicate can be reduced. In addition, since the list information is received from the terminal device, accurate information can be used. In addition, since accurate information is used, the accuracy of priority can be improved. Moreover, since the allocation request received from the terminal device only includes the identification number of the base station device to which the terminal device can be connected, the amount of information transmitted from the terminal device can be reduced. In addition, since the base information is generated in the base station device after estimating the presence direction of the terminal device, the amount of information transmitted from the terminal device can be reduced. In the base station apparatus, subchannel allocation can be performed so that each terminal apparatus can allocate a subchannel from any of the base station apparatuses.

  In the above, this invention was demonstrated based on the Example. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to the combination of each component and each processing process, and such modifications are also within the scope of the present invention. .

  In the embodiment of the present invention, the radio resource allocating unit 38 uses the resource information included in the allocation request and the resource information stored in the storage unit 30. However, the present invention is not limited to this. For example, when the terminal apparatus 12 newly transmits an allocation request, the terminal apparatus 12 to which a subchannel has already been allocated may transmit resource information and the like. Further, the base station device 10 may request transmission to all the terminal devices 12 or some of the terminal devices 12. According to this modification, new information can be used even for the terminal device 12 to which a subchannel has already been assigned.

  In the embodiment of the present invention, the radio resource allocation unit 38 performs subchannel release when there are no more free subchannels. However, the present invention is not limited to this. For example, even if there is an empty subchannel, the radio resource allocation unit 38 may perform release based on the priority order. According to this modification, the processing amount in the base station apparatus 10 can be reduced.

It is a figure which shows the structure of the communication system which concerns on the Example of this invention. It is a figure which shows the frame structure in the communication system of FIG. It is a figure which shows the frame structure in the communication system of FIG. It is a figure which shows the frame structure in the communication system of FIG. It is a figure which shows arrangement | positioning of the subchannel in the communication system of FIG. It is a figure which shows the structure of the terminal device of FIG. It is a figure which shows the data structure of the table memorize | stored in the memory | storage part of FIG. It is a figure which shows the structure of the base station apparatus of FIG. It is a flowchart which shows the transmission procedure of the allocation request | requirement in the terminal device of FIG. It is a flowchart which shows the allocation procedure in the base station apparatus of FIG. It is a flowchart which shows the transmission procedure of the allocation request | requirement in the terminal device which concerns on the modification of this invention. It is a flowchart which shows the allocation procedure in the base station apparatus which concerns on the modification of this invention. It is a flowchart which shows the allocation procedure in the base station apparatus which concerns on another modification of this invention.

Explanation of symbols

  10 base station devices, 12 terminal devices, 20 RF units, 22 baseband processing units, 24 modulation / demodulation units, 26 IF units, 28 radio control units, 30 storage units, 32 control channel determination units, 38 radio resource allocation units, 50 RF Unit, 52 modulation / demodulation unit, 54 IF unit, 56 radio control unit, 58 storage unit, 100 communication system.

Claims (6)

An acquisition unit for acquiring information on an empty channel of a base station apparatus connectable to a terminal apparatus;
Based on the information acquired in the acquisition unit, for each of a plurality of terminal devices, a grant unit that gives a higher priority to a terminal device that is less likely to be connected to another base station device;
An allocating unit that allocates a channel to a terminal device while referring to the priority order given by the granting unit;
A communication unit that communicates with a terminal device to which a channel is allocated in the allocation unit;
Equipped with a,
When there is no empty channel to be allocated to the new terminal device when the channel allocation request is made by the new terminal device, the allocating unit has another priority lower than the priority level assigned to the new terminal device. A base station apparatus characterized by releasing a channel allocated to, and allocating the released channel to the new terminal apparatus. The communication unit is a channel allocation request from a terminal device, and receives a channel allocation request including information on a base station device to which the terminal device can be connected,
The base station apparatus according to claim 1, wherein the acquisition unit extracts information related to a base station apparatus to which a terminal apparatus can be connected from a channel allocation request received by the communication unit. The communication unit receives a channel allocation request from a terminal device, and includes a channel allocation request including information for identifying a base station device to which the terminal device can be connected,
The acquisition unit is configured to extract information for identifying a base station device connectable to a terminal device from a channel allocation request received in the communication unit, and a base station device included in the extracted information. The base station apparatus according to claim 1, further comprising means for receiving information regarding a channel that can be allocated by the base station apparatus as information regarding the base station apparatus to which the terminal apparatus can be connected. A receiving unit that receives information on a channel that can be allocated by the base station apparatus from another base station apparatus;
Further comprising a specifying unit for specifying the presence direction of another base station device that has received information in the receiving unit;
The communication unit receives a channel allocation request from a terminal device,
The acquisition unit is configured to identify a presence direction of a terminal device that has received a channel allocation request in the communication unit, a presence direction of the terminal device, a presence direction of another base station device identified by the identification unit, The base station apparatus according to claim 1, further comprising: means for generating information related to a base station apparatus to which a terminal apparatus can be connected based on information received by the reception unit. Obtaining information on available channels of base station devices to which the terminal device can be connected;
Based on the acquired information, for each of a plurality of terminal devices, a step of giving a higher priority to a terminal device that is less likely to be connected to another base station device;
Allocating a channel to a terminal device while referring to the assigned priority order;
Communicating with a terminal device assigned the channel;
Equipped with a,
In the assigning step, when there is no empty channel to be assigned to the new terminal device when a channel assignment request is made by the new terminal device, another terminal device having a lower priority than the priority assigned to the new terminal device. A communication method , comprising: releasing a channel assigned to, and assigning the released channel to the new terminal device . Obtaining information on available channels of base station devices to which the terminal device can be connected;
Based on the acquired information, for each of a plurality of terminal devices, a step of giving a higher priority to a terminal device that is less likely to be connected to another base station device;
Allocating a channel to a terminal device while referring to the assigned priority order;
Communicating with the terminal device to which the channel is assigned ,
In the assigning step, when there is no empty channel to be assigned to the new terminal device when a channel assignment request is made by the new terminal device, another terminal device having a lower priority than the priority assigned to the new terminal device. A program for causing a computer to release a channel assigned to the terminal and assign the released channel to the new terminal device .

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