JP2009005153A - Radio communication apparatus, and communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio communication apparatus and a communication method, capable of preventing deterioration of a communication quality between the radio communication apparatus and the other apparatus in TDMA/TDD system radio communication. <P>SOLUTION: A variation state of a propagation path with the other apparatus is detected and a pair of time slots are assigned. The pair of time slots have uplink/downlink time slots different in duration width from each other. The time-series order in the uplink time slot and the time-series order in the downlink time slot are equalized. The pair of time slots are selected based on the variation state of the detected propagation path. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention uses a time division multiple access / time division duplex system having a plurality of time slots in wireless communication with a plurality of other terminals, and the time width of the uplink time slot and the time width of the downlink time slot are The present invention relates to a radio communication apparatus and a communication method that are different and control a signal of a downlink time slot based on an uplink time slot signal.

  Conventionally, various wireless communication methods have been proposed, and one of them is a time division multiple access / time division duplex (hereinafter referred to as TDMA /) that is used in a wireless communication system such as an i-Burst (registered trademark) system. There is a TDD (Time Division Multiple Access / Time Division Duplex) method (see, for example, Non-Patent Document 1).

  FIG. 11 shows a frame configuration in a wireless communication system such as an i-Burst (registered trademark) system. As shown in FIG. 11, in such a wireless communication system, one carrier is divided into frames every 5 ms, and the frames are further divided into three uplink time slots U # 1 to U # 3 and downlink time slot D #. 1 to D # 3 are divided into a total of 6 time slots. Also, as shown in FIG. 10, in such a wireless communication system, when the base station and each terminal 10a to 10c communicate, uplink time slots U # 1 to U # 3 and downlink time slots D # 1 to D # 3 are communicated using communication channels CH1 to CH3 assigned one by one in time-sequential order.

  On the other hand, in the above-described wireless communication system, adaptive array technology using a plurality of antenna elements is applied, and the base station transmits a downlink time slot signal to be transmitted based on the received uplink time slot signal. Directivity control is performed. Specifically, for example, the base station calculates a weighting factor for each antenna element based on the signal of the uplink time slot U # 1 received from the terminal 10a. Then, when the base station transmits the signal of the downlink time slot D # 1 to the terminal 10a, the base station adjusts the amplitude and phase of the signal output from each antenna element based on the calculated weighting factor, and sends the signal to the terminal 10a. The directivity control of the signal to be transmitted is performed.

With the above-described directivity control, in such a wireless communication system, the base station increases the strength of the transmission signal and the sensitivity of the reception signal with respect to a specific terminal, while the strength of the transmission signal with respect to other terminals is increased. The sensitivity of the received signal is lowered to reduce mutual interference, and stable communication is performed with each terminal.
“Series iBurst”, Nikkei Communication, Nikkei BP, November 1, 2005, No. 449, p. 114-119

  Here, in the wireless communication system such as the i-Burst (registered trademark) system described above, the downlink information is transmitted with respect to the time width of the uplink time slot so that the downlink information amount transmitted from the base station to the terminal increases. The time width of the time slot is doubled. That is, the time width of the upstream time slot is different from the time width of the downstream time slot. Therefore, the intervals Δt1 to Δt3 from the uplink time slot to the downlink time slot are different for each terminal 10a to 10c using the communication channels CH1 to CH3.

  Here, for example, it is assumed that the terminal 10a communicates using the communication channel CH3 to which the uplink time slot U # 3 and the downlink time slot D # 3 having the longest interval Δt3 are allocated. At this time, the terminal 10a or an object (for example, a vehicle) existing around the terminal 10a moves at a high speed (from 100 km / h), so that the propagation path between the base station and the terminal 10a is transmitted during the interval Δt3. The state may have fluctuated rapidly. In such a case, the directivity of the signal in the downlink time slot D # 1 is not appropriate. As a result, there has been a problem that the communication quality between the base station and the terminal deteriorates, for example, the reception level of the terminal 10a is reduced.

  Therefore, the present invention has been made in view of such a situation, and in a TDMA / TDD scheme wireless communication in which the time width of the uplink time slot and the time width of the downlink time slot are different, An object of the present invention is to provide a wireless communication prime minister and a communication method capable of suppressing deterioration of communication quality with a base station.

  In order to solve the problems described above, the present invention has the following features. First, the first feature of the present invention is to use a time division multiple access / time division duplex method in radio communication with a plurality of other devices (for example, mobile terminals) and control a downlink signal based on the uplink signal. A wireless communication device (for example, a base station), a propagation path state detection unit that detects a fluctuation state of a propagation path with the other device based on a received wireless signal from the other device, and a pair of An allocation unit that allocates a time slot to the other device, and the pair of time slots includes an upstream time slot that is a transmission period of the upstream signal and a downstream time slot that is a transmission time of the downstream signal. However, the time width of the uplink time slot and the time width of the downlink time slot are different from each other in the time series order in the uplink time slot and the time series in the downlink time slot. Equal to the order, the assignment unit, on the basis of the variation state of the propagation path is detected by the propagation path state detection unit, assigned to select the pair of time slots, and summarized in that.

  According to such a wireless communication apparatus, it is possible to select and assign a pair of time slots composed of an uplink time slot and a downlink time slot having different time widths based on the fluctuation state of the propagation path. For this reason, even when the propagation path between other devices fluctuates, a pair of time slots in which the interval from the upstream time slot to the downstream time slot has a length suitable for the other device is adaptively used. Can be set.

  A second feature of the present invention relates to the first feature of the present invention, wherein the propagation path state detection unit is configured to determine a state of a propagation path with the other device based on the detected fluctuation state of the propagation path. The gist of the present invention is to grasp a fluctuation cycle in which the pair of time slots is selected, and the assigning unit selects and assigns the pair of time slots according to the fluctuation cycle grasped by the propagation path state detecting unit.

  Since such a wireless communication apparatus can accurately detect the fluctuation state of the propagation path by grasping the fluctuation period, when the propagation path between other apparatuses fluctuates, such a fluctuation period Accordingly, the pair of time slots can be more appropriately allocated. Therefore, when the state of the propagation path with the other device suddenly fluctuates due to movement of the other device at the communication destination or the object existing around the other device at the communication destination at a high speed (from 100 km / h) However, deterioration of communication quality can be suppressed.

  A third feature of the present invention relates to the first or second feature of the present invention, wherein the allocating unit is configured to select the plurality of other ones according to the fluctuation state of the propagation path grasped by the propagation path state detection unit. The gist is to determine the order of the devices and select and assign the pair of time slots based on the order.

  In such a wireless communication device, when there are a plurality of other devices, the order of the plurality of other devices is determined according to the fluctuation state of the propagation path for each other device, and the pair of time slots is based on the order. Can be selected and assigned. Accordingly, the pair of time slots can be appropriately selected and assigned to a plurality of other devices.

  A fourth feature of the present invention relates to the second or third feature of the present invention, wherein the assigning unit determines that the other terminal in the order of the smaller value indicating the grasped fluctuation period of the propagation path is the uplink time. The gist is to select and assign the pair of time slots so that the time difference between the slot and the downlink time slot is shortened.

  According to such a wireless communication device, in the wireless communication with another device, the other device having a smaller value indicating the propagation period of the propagation path has a shorter interval from the upstream time slot to the downstream time slot. The pair of time slots can be selected and assigned. As a result, based on the uplink time slot signal received from the other device, the downlink time slot signal for which the directivity is controlled for the other device can be transferred to the other device or an object existing around the other device. It is possible to transmit before the situation (for example, the vehicle) moves greatly (high speed movement), that is, before the fluctuation state of the propagation path changes rapidly. For this reason, it can reduce reliably that the quality of communication with another apparatus falls.

  A fifth feature of the present invention relates to the second feature of the present invention, wherein the detection of the fluctuation state of the propagation path by the propagation path state detection unit is performed by changing the power value of the received radio signal from the other device. The gist is that it is performed by detecting.

  According to such a feature, the wireless communication device can more accurately detect the fluctuation cycle of the propagation path state from the fluctuation cycle of the power value of the received radio signal.

  A sixth feature of the present invention relates to the second feature of the present invention, wherein the propagation path state detection unit detects the propagation state of the propagation path by detecting a Doppler fluctuation of the received radio signal. This is the gist.

  According to such a feature, the wireless communication device can more accurately detect the fluctuation period from the period of the Doppler fluctuation amount.

  A seventh feature of the present invention is a communication method in a radio communication apparatus that uses a time division multiple access / time division duplex method in radio communication with a plurality of other apparatuses and controls a downlink signal based on an uplink signal. And detecting a fluctuation state of a propagation path with the other device, and allocating a pair of time slots to the other device, wherein the pair of time slots is a transmission period of the uplink signal. An uplink time slot and a downlink time slot that is a transmission time of the downlink signal, and the time width of the uplink time slot is different from the time width of the downlink time slot, and the time series in the uplink time slot The upper order is equal to the time-series order in the downlink time slot, and in the assigning step, the detected fluctuation state of the propagation path Based on, assigned by selecting the pair of time slots, and summarized in that.

  According to the characteristics of the present invention, in the TDMA / TDD system wireless communication in which the time width of the uplink time slot and the time width of the downlink time slot are different, other devices as communication destinations or peripherals of other devices as communication destinations Even when the state of the propagation path with the wireless communication device changes rapidly due to the movement of an object existing in the wireless communication device, it is possible to suppress deterioration in communication quality.

  Next, 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 Embodiment]
As illustrated in the schematic diagram of FIG. 1, in the present embodiment, a case where wireless communication is performed between the base station 100 and a plurality of terminals 10 a to 10 c will be described as an example. In the present embodiment, a time division multiple access / time division duplex system (hereinafter referred to as TDMA / TDD) adopted in the i-Burst (registered trademark) system or the like between the base station 100 and the terminals 10a to 10c. System) and spatial multiplexing technology, wireless communication is performed.

  Here, in the present embodiment, in the TDMA / TDD system described above, one frame is 5 ms, and the one frame is composed of three uplink time slots and three downlink time slots, for a total of six times. It consists of slots. Note that although there is a guard time between the uplink time slot and the downlink time slot, the description is omitted. Also, the time width of the upstream time slot is different from the time width of the downstream time slot. Specifically, the time width of the downlink time slot according to the present embodiment is twice the time width of the uplink time slot.

  In the TDMA / TDD scheme, three signals are multiplexed in one time slot by spatial multiplexing. Note that the number of uplink and downlink time slots and the number of spatially multiplexed signals are not limited to the numbers described above. Moreover, in this embodiment, although the base station 100 is provided in the radio | wireless communications system, in this radio | wireless communications system, description regarding other structures, such as a network and a server, is abbreviate | omitted.

  In the present embodiment, the terminals 10a to 10c are assumed to be mobile devices such as mobile phones, PDAs (Personal Digital Assistants), and notebook computers. Further, in the present embodiment, as shown in FIG. 1A, the terminals 10b and 10c do not move and exist at substantially the same position, and the terminal 10a performs wireless communication with the base station 100 at the point A. A case will be described as an example in which the user moves to the point B after starting communication. In addition, in the present embodiment, as shown in FIG. 1B, the terminals 10b to 10c do not move and exist at substantially the same position, and the terminal 10a is connected to the base station 100 at the point A. When an object X (for example, a vehicle) existing around the terminal 10a moves at high speed from the point C to the point D after the communication is started (between the base station 100 and the terminal 10a) Is taken as an example).

  Further, when starting wireless communication with the base station 100, the terminals 10a to 10c receive a resource map transmitted from the base station 100 and communicate based on the time slot number included in the resource map. Determine the channel.

  Here, the communication channel described above is a pair of time slots in which a predetermined time sequence of upstream time slots and a time sequence of downstream time slots are equal in a specific communication frequency (carrier). This is a communication transmission line between the terminals 10a to 10c and the base station 100. The relationship between the communication channel and the time slot pair according to the present embodiment will be described in detail later (see FIG. 6). Further, the resource map is information periodically transmitted from the base station 100 within the radio range C100 of the own station, and the resource map includes uplink time slots in all communication channels that are not currently used. The number and the downlink time slot number, and the communication frequency are included (see FIG. 7).

  Further, upon receiving this resource map, the terminals 10a to 10c select one communication channel to be used for communication from the communication channels included in the resource map, and the uplink time slot number and downlink of the selected communication channel. Communication is started with the time slot number and the communication frequency.

  In addition, when the terminals 10a to 10c according to the present embodiment receive the dedicated resource map transmitted from the base station 100 after starting communication, the terminals 10a to 10c select the communication channel included in the dedicated resource map and the uplink in the selected communication channel. Communication is started with the time slot number and the downlink time slot number, and the communication frequency.

  Here, the individual resource map is information transmitted when the base station 100 changes the communication channel used with the communicating terminals 10a to 10c. The individual resource map includes the uplink time slot number and downlink time slot number of the communication channel to be changed, and the communication frequency.

(Overall schematic configuration of base station 100)
Next, the configuration of the base station 100 according to the present embodiment 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 100 and that is not illustrated or omitted.

  The base station 100 according to the present embodiment controls downlink time slot signals based on uplink time slot signals in wireless communication with a plurality of terminals 10a to 10c. In addition, the base station 100 includes an adaptive array antenna including a plurality of antenna elements, and executes adaptive array processing for controlling the directivity of radio signals for each of the terminals 10a to 10c. Specifically, as shown in FIG. 2, the base station 100 controls the directivity of signals transmitted and received between the radio processing unit 200 that performs radio communication with the terminals 10a to 10c and the terminals 10a to 10c. A signal processing unit 300 that performs adaptive array processing, and a control unit 400A that controls various functions in the base station 100.

  The radio processing unit 200 includes a first radio unit 201 to a twelfth radio unit 212 having antenna elements, and functions as an adaptive array antenna.

  The first radio unit 201 to the twelfth radio unit 212 perform conversion such as down-conversion on the radio signals received from the terminals 10a to 10c, and convert the converted signals into the first signal control units 301 to 4 of the signal processing unit 300. The signal is output to a signal control unit 304 (described later). In addition, the first wireless unit 201 to the twelfth wireless unit 212 perform conversion such as up-conversion on the signal input from the signal processing unit 300, and transmit the converted signal to the terminals 10a to 10c. The first wireless unit 201 to the twelfth wireless unit 212 are configured similarly.

  The signal processing unit 300 weights each signal input / output from the first wireless unit 201 to the twelfth wireless unit 212, and transmits a signal whose directivity is controlled to the first wireless unit 201 to the twelfth wireless unit 212. In addition, adaptive array processing is performed to increase the sensitivity of signals input from the first wireless unit 201 to the twelfth wireless unit 212. Specifically, the signal processing unit 300 includes a first signal control unit 301 to a fourth signal control unit 304. Since the first signal control unit 301 to the fourth signal control unit 304 are configured in the same manner, the configuration of the first signal control unit 301 will be specifically described.

  As shown in FIG. 3, the first signal control unit 301 includes a weight coefficient calculation unit 3101, reception signal multiplication units 3201 to 3212, a reception signal combining unit 3301, and a transmission signal separation unit. 3401 and transmission signal multipliers 3501 to 3512.

  The weighting factor calculation unit 3101 calculates the weighting factor w of the transmission signal or the reception signal. Here, the weight coefficient w is a coefficient for adjusting the amplitude and phase of the received signal and the transmitted signal. The weight coefficient w changes when the terminals 10a to 10c move.

  Further, the weighting factor calculation unit 3101 calculates twelve weighting factors w for each signal based on each signal output from the first wireless unit 201 to the twelfth wireless unit 212, and calculates the calculated weighting factor w, The data are output to multiplication sections 3201 to 3212 and multiplication sections 3501 to 3512, respectively. At this time, the weighting factor calculation unit 3101 calculates the weighting factor w such that an error from a sample signal such as a unique word (UW) is minimized (least square error method: MMSE). Note that the weighting factor calculation unit 3101 calculates the above-described weighting factor w for each uplink time slot of the terminals 10a to 10c in one frame.

  In addition, the weighting factor calculation unit 3101 uses, for example, one weighting factor w calculated based on the signal output from the first radio unit 201 among the calculated twelve weighting factors w. Notification is made to the propagation path state detection unit 403 (described later, see FIG. 4). In the present embodiment, a case where transmission / reception signals with the terminals 10a to 10c are assigned to the first signal control unit 301 will be described as an example. Therefore, in the present embodiment, the weighting factor w in the transmission / reception signals with the terminals 10 a to 10 c is output from the first signal control unit 301.

  The multipliers 3201 to 3212 weight the signals output from the first radio unit 201 to the twelfth radio unit 212 with the weighting coefficient w and output the signals to the synthesis unit 3301. The combining unit 3301 combines the signals output from the multiplying units 3201 to 3212 and outputs the combined signals to the TDMA separation processing unit 401 (described later, see FIG. 4) of the control unit 400A.

  Separating section 3401 separates the signal output from TDMA multiple processing section 405 (described later, see FIG. 4) of control section 400A, and outputs the separated signals to multiplication sections 3501 to 3512. In addition, the multipliers 3501 to 3512 weight the signal output from the separator 3401 with the weighting coefficient w, and output the weighted signal to each of the first radio unit 201 to the twelfth radio unit 212.

  A plurality of antenna elements can be used during wireless communication with the terminals 10a to 10c by the signal processing performed by the weight coefficient calculation unit 3101, the multiplication units 3201 to 3212, the synthesis unit 3301, the separation unit 3401, and the multiplication units 3501 to 3512 described above. In the adaptive array antenna having the above, directivity control is performed on signals received and transmitted simultaneously.

(Configuration of control unit 400A)
Next, the configuration of the control unit 400A according to the present embodiment will be specifically described. The control unit 400A according to the present embodiment controls voice information or data information signals communicated between the terminals 10a to 10c and the base station 100 by the TDMA / TDD scheme.

  Further, the control unit 400A notifies the resource map to be notified to the terminals 10a to 10c via the wireless processing unit 200 and the signal processing unit 300.

  Further, various functions related to the present invention will be described in detail with reference to FIG. As shown in FIG. 4, the control unit 400A according to the present embodiment includes a TDMA separation processing unit 401, a storage unit 402, a propagation path state detection unit 403, a time slot allocation unit (allocation unit) 404, and TDMA multiplexing. And a processing unit 405.

  The TDMA separation processing unit 401 receives the signal from the combining unit 3301, demodulates the signal, and separates the signal by the TDMA / TDD method. Further, the TDMA multiplexing processing unit 405 modulates signals to be transmitted to the terminals 10a to 10c, multiplexes them by the TDMA / TDD system, and outputs the multiplexed signals to the demultiplexing unit 3401.

  The storage unit 402 includes a propagation path fluctuation table T1 and an allocation table T2. As illustrated in FIG. 5, the propagation path fluctuation table T1 stores a terminal ID for identifying the terminals 10a to 10c and a value indicating a fluctuation state of the propagation path of the terminals 10a to 10c in association with each other. Here, the value indicating the fluctuation state of the propagation path is a value indicating the magnitude of the fluctuation state of the propagation path between each terminal and the base station 100 in the terminals 10a to 10c, that is, the state of the propagation path is changed. Is a value indicating the fluctuation period (fa) to be stored, and is stored by the propagation path state detection unit 403 described later.

  In the present embodiment, the terminal ID of the terminal 10a will be described as UE10a, the terminal ID of the terminal 10b will be described as UE10b, and the terminal ID of the terminal 10c will be described as UE10c. In the present embodiment, the value indicating the fluctuation period (fa) of the propagation path corresponding to the terminal 10a (UE10a) is defined as the fluctuation period c1, and the value indicating the fluctuation period (fa) corresponding to the terminal 10b (UE10b) is defined as the fluctuation period. A value indicating the fluctuation period (fa) of the propagation path corresponding to the terminal 10c (UE 10c) will be described as a fluctuation period c3.

  As shown in FIG. 6, the allocation table T2 stores the communication destination terminal ID and the time slot numbers allocated to the terminals 10a to 10c corresponding to the terminal ID in association with each other. In this embodiment, the upstream time slot numbers are described as U # 1 to U # 3 in time series, and the downstream time slot numbers are described as D # 1 to D # 3 in time series. In the present embodiment, the description of the spatially multiplexed slot numbers is omitted.

  In the present embodiment, a plurality of communication channels that are a pair of time slots are provided. Specifically, in this embodiment, the pair of the uplink time slot number U # 1 and the downlink time slot number D # 1 is the communication channel CH1, and the uplink time slot number U # 2 and the downlink time slot number D # 2 An example will be described in which a pair is a communication channel CH2 and a pair of an uplink time slot number U # 3 and a downlink time slot number D # 3 is a communication channel CH3.

  The propagation path state detection unit 403 is connected to the first wireless unit 201 to the twelfth wireless unit 212 and the storage unit 402. The propagation path state detection unit 403 detects the variation state of the propagation path, and grasps the variation period (fa) in which the state of each propagation path with the terminals 10a to 10c varies based on the detected variation state of the propagation path. . The propagation path state detection unit 403 grasps the fluctuation of the power value of the uplink signal received by the first radio unit 201 to the twelfth radio unit 212 as the fluctuation period (fa). Specifically, for example, the propagation path state detection unit 403 periodically acquires a received power value that changes due to Doppler fluctuation caused by the movement of the terminal 10a or the movement of the object X existing around the terminal 10a. And grasping the fluctuation period (fa) of the received power value. In addition, the propagation path state detection unit 403 notifies the storage unit 402 of a value indicating the grasped fluctuation cycle (fa). The storage unit 402 stores a value related to the fluctuation period (fa) for each terminal notified from the propagation path state detection unit 403.

  The time slot allocation unit 404 is connected to the storage unit 402. In the communication channel used between the terminals 10a to 10c, the time slot allocating unit 404 has an interval from the uplink time slot to the downlink time slot as the terminals 10a to 10c having a smaller value indicating the obtained fluctuation period (fa). A pair of uplink time slots and downlink time slots are selected and assigned so as to be shorter. Specifically, when the value indicating the fluctuation period (fa) stored in the propagation path fluctuation table T1 is updated, the time slot allocating unit 404 changes the terminal IDs in ascending order of the values indicating the fluctuation period (fa). To decide. As a result, for the terminal in the first order, the value indicating the fluctuation period (fa) is the smallest value, which means that the propagation path fluctuates the most. That is, it means that the propagation path fluctuates most severely when the terminal or an object existing around the terminal moves at high speed.

  The time slot allocating unit 404 periodically refers to the allocation table T2 (FIG. 6) to obtain the uplink time slot number and the downlink time slot number and the communication frequency for all communication channels that are not currently used. The generated resource map is transmitted to the radio range C100 of the own station via the TDMA multiple processing unit 405, the signal processing unit 300, and the radio processing unit 200.

  FIG. 7 shows an example of information included in the resource map. As shown in FIG. 7, the resource map includes a communication channel that is not currently used, an uplink time slot number and a downlink time slot number that are associated in advance with the communication channel, and a communication frequency. .

  In the example of FIG. 7, since it is assumed that the communication channels CH1 to CH3 are the same carrier, all are shown as the communication frequency L. Note that the resource map described above is transmitted from the base station 100 using the control channel, and is received by the terminals 10a to 10c before the start of communication.

  In addition, the time slot allocation unit 404 has the following functions for the terminals 10a to 10c that have started communication. The time slot allocating unit 404 determines the time series of the upstream time slots so that the intervals between the upstream time slots and the downstream time slots become shorter for the terminals 10a to 10c having a smaller fluctuation period (fa) after the start of communication. And a pair of time slots having the same time-sequential order of downlink time slots.

  Specifically, when the fluctuation period (fa) stored in the propagation path fluctuation table T1 is updated, the time slot allocation unit 404 determines the terminal IDs in order of increasing fluctuation period (fa). In addition, referring to the allocation table T2, it is determined whether or not the determined order of the terminal ID is different from the order of the communication channels CH1 to CH3 in the allocation table T2.

If the time slot allocation unit 404 determines that the order determined in ascending order of the variation period (fa) is different from the order of the communication channels CH1 to CH3, the time slot allocation unit 404 is based on the order of the variation period (fa) in the smallest order. Communication channel CH1 (uplink time slot number U # 1 and downlink time slot number D # 1), communication channel so that the interval from the uplink time slot to the downlink time slot becomes narrower in order from the terminal ID with the smallest fluctuation period (fa). Each corresponding communication channel CH1 to CH3 in the order of CH2 (uplink time slot number U # 2 and downlink time slot number D # 2) and communication channel CH3 (uplink time slot number U # 3 and downlink time slot number D # 3). Select each.
The assignment is changed based on the above-described interval Δt from the uplink time slot to the downlink time slot. However, the interval Δt may be appropriately changed according to the CPU and the processing system. That is, in the present embodiment, i-Burst (registered trademark) is described as an example. In such a system, the time width of the downlink time slot is twice the time width of the uplink time slot. Therefore, for example, when a three-slot period is required for the weight calculation, it is desirable to set so that the downlink time slot number D # 2 is assigned to the uplink time slot number U # 3.

  Note that the time slot allocation unit 404 does not perform this operation when the determined order is the same as the order before the determination. When there is one terminal that communicates with base station 100, time slot assignment section 404 assigns the time slot of communication channel CH1 to the terminal.

  Further, the time slot specifying unit 404 sends the uplink time slot number and the downlink time slot number in each of the communication channels CH1 to CH3, the communication frequency, and the terminals 10a to 10c having the terminal IDs corresponding to the specified communication channels CH1 to CH3. Is transmitted through the TDMA multiple processing unit 406, the signal processing unit 300, and the radio processing unit 200.

  As described above, the time slot allocating unit 404 transmits the individual resource map to the terminals 10a to 10c, thereby causing the terminals 10a to 10c to select the specified communication channels CH1 to CH3 and the terminals 10a to 10c. Each communication channel CH1 to CH3 used in communication with 10c is determined.

  Also, the time slot allocation unit 404 notifies the TDMA separation processing unit 401 and the TDMA multiplexing processing unit 405 of the changed time slot numbers of the communication channels CH1 to CH3 every time the communication channels CH1 to CH3 with the terminals 10a to 10c are changed. As a result, multiplexing and demultiplexing of transmission / reception signals by the TDMA / TDD scheme is appropriately performed.

(Operation of base station 100 according to this embodiment)
Next, the operation of base station (wireless communication apparatus) 100 described above will be described. In the present embodiment, the terminals 10b to 10c are already communicating with the base station 100 and do not move at substantially the same position, and the terminal 10a is located at the point A shown in FIG. A case will be described as an example where communication is started with the base station 100 and the vehicle moves toward the point B at high speed after the communication is started. In addition, in this embodiment, the terminal 10b to the terminal 10c do not move at substantially the same position while already communicating with the base station 100, and the terminal 10a is located at the point shown in FIG. In A, when communication with the base station 100 is started and an object X (for example, a vehicle) existing around the terminal 10a moves from the point C to the point D at high speed after the communication starts (base The case where the station 100 and the terminal 10a are traversed at high speed will be described as an example.

  FIG. 8 is a sequence diagram showing an operation when the base station 100 that has already communicated with the terminals 10b to 10c newly starts communication with the terminal 10a.

  In step S101, the terminal 10a receives the resource map transmitted from the base station 100. Here, since the base station 100 uses the communication channels CH1 to CH2 (CH1 for the terminal 10c and CH2 for the terminal 10b) in communication with the terminals 10b to 10c, the resource map includes the communication channel CH3. An uplink time slot number U # 3 and a downlink time slot number D # 3, and a communication frequency are included.

  In step S102, the terminal 10a selects the uplink time slot # U3 and downlink time slot # D3 of the communication channel CH3 included in the resource map, and the communication frequency, and starts communication. In the case of an i-Burst (registered trademark) system, the following process is performed to start such communication. That is, when the terminal 10a selects the uplink time slot # U3 and downlink time slot # D3 of the communication channel CH3 and the communication frequency included in the resource map, the uplink time slot # U3 and downlink time slot of the communication channel CH3 are selected. In order to instruct the base station 100 to use # D3, “Configuration Request Information” is transmitted to the base station 100 using the control channel (CCH). Then, the base station 100 transmits “Configuration Message information” to the terminal 10a.

  Then, using the random access channel (RaCH), the terminal 10a transmits “Request Access information” to the base station 100, and the base station 100 transmits “Access Assignment information” to the terminal 10a. Then, the terminal 10a transmits “Capability information” to the base station 100, and the base station 100 transmits “BS Params information” to the terminal 10a. Further, the terminal 10a transmits “UT Params information” to the base station 100, and the base station 100 transmits “Reg Params information” to the terminal 10a.

  At this time, the terminal 10a transmits “Request Access information” to the base station 100, and the base station 100 transmits “Access Assignment information” to the terminal 10a.

  After these steps, the terminal 10c uses the communication channel CH1, the terminal 10b uses the communication channel CH2, and the terminal 10a uses the communication channel CH3. Here, the terminals 10a to 10c The fluctuation periods (fa) C1 to C3 are assumed to be C1> C2> C3. At this time, the terminal 10a starts moving toward the point B at a high speed ((a) in FIG. 1). Alternatively, it is assumed that an object X (for example, a vehicle) existing around the terminal 10a starts moving at a high speed from the point C to the point D ((b) in FIG. 1).

  In step S103, in the base station 100, in the propagation path fluctuation table T1, the value C1 indicating the fluctuation period (fa) in the terminal 10a (UE10a) is changed to the fluctuation period (fa) C2 in the terminal 10b (UE10b) and the terminal 10c (UE10c). ) In the fluctuation cycle (fa) C3 (C2> C3> C1). Then, the time slot allocation unit 404 specifies that the communication channel CH1 (uplink time slot number U # 1 and downlink time slot number D # 1) is changed in communication with the terminal 10a, and in communication with the terminal 10c. The communication channel CH2 (uplink time slot number U # 2 and downlink time slot number D # 2) is specified to be changed, and in communication with the terminal 10b, the communication channel CH3 (uplink time slot number U # 3 and downlink time slot It is specified to change to slot number D # 3).

  In step S104, the time slot allocation unit 404 transmits an individual resource map including the specified communication channel CH1 to the terminal 10a, and transmits an individual resource map including the specified communication channel CH2 to the terminal 10c. The dedicated resource map including the specified communication channel CH3 is transmitted to the terminal 10b. In the case of the i-Burst (registered trademark) system, at this time, the base station 100 transmits "Acknowledged Mode (AM) Message information" to the terminals 10a to 10c.

  In step S105, the terminal 10a resumes communication on the communication channel CH1 included in the dedicated resource map. Also, the terminal 10c starts communication on the communication channel CH2 included in the dedicated resource map. Further, the terminal 10b starts communication on the communication channel CH3 included in the dedicated resource map.

  At this time, in order to instruct the base station 100 to use the communication channel CH1, the terminal 10a transmits “Request Access information” to the base station 100, and the base station 100 transmits “Access Assignment” to the terminal 10a. Send "information". In addition, since the terminal 10c instructs the base station 100 to use the communication channel CH2, the base station 100 transmits “Request Access information” to the base station 100, and the base station 100 transmits “Access Assignment information” to the terminal 10c. Send. Further, in order to instruct the base station 100 to use the communication channel CH3, the terminal 10b transmits “Request Access information” to the base station 100, and the base station 100 transmits “Access Assignment information” to the terminal 10b. Send.

  Next, the process of step S103 described above will be described more specifically. FIG. 9 is a flowchart showing the control operation in the control unit 400A of the base station 100 in step S103 described above. It is assumed that the fluctuation periods C1 to C3 of the terminals 10a to 10c before the operation start are C1> C2> C3.

  In step S1061, the propagation path state detection unit 403 of the control unit 400A changes the fluctuation of the power value of the uplink signal received by the first radio unit 201 to the twelfth radio unit 212 for each of the terminals 10a to 10c. It is grasped as (fa), and values (C1 to C3) indicating the grasped fluctuation period (fa) are notified to the storage unit 402. The storage unit 402 stores the values (C1 to C3) indicating the variation period (fa) notified from the propagation path state detection unit 403 in association with the terminal IDs (UE10a to UE10c) in the propagation path variation table T1. At this time, since the terminal 10a or the object X existing around the terminal 10a is moving at high speed, the value (C2) indicating the fluctuation cycle (fa) of the terminal 10b stored in the propagation path fluctuation table T1 and the terminal The value (C1) indicating the fluctuation period (fa) of the terminal 10a is smaller than the value indicating the fluctuation period (fa) of 10c (C2> C3> C1).

  In step S1062, when the fluctuation period (fa) stored in the propagation path fluctuation table T1 is updated, the time slot allocation unit 404 sets the terminal IDs (UE10a and UE10c) in ascending order of the fluctuation period (fa). Determine the order. Then, it is determined whether the determined order is different from the order before the determination. In this example, the time slot allocation unit 404 determines that the order of terminal IDs corresponding to the fluctuation period (fa) in the propagation path fluctuation table T1 is different from the order of terminal IDs corresponding to the communication channels CH1 to CH3. To do.

  In step S1063, when the time slot allocation unit 404 determines that the determined order of the terminal IDs is different from the order of the terminal IDs corresponding to the communication channels CH1 to CH3, based on the order, the time variation allocation (fa The communication channel CH1 (uplink time slot number U # 1) is assigned to the terminal ID (UE10a) of the terminal 10a so that the interval from the uplink time slot to the downlink time slot becomes shorter in order from the terminal ID having a smaller value indicating). And downlink time slot number D # 1) are selected and assigned, and communication channel CH2 (uplink time slot number U # 2 and downlink time slot number D # 2) is selected for terminal ID (UE10c) of terminal 10c. Assigned to the terminal ID of the terminal 10b (UE10b), the communication channel CH3 (uplink Assigning select timeslot number U # 3 and downlink time slot number D # 3).

  Note that the time slot allocation unit 404 determines in step S1062 that the order of terminal IDs determined based on the variation period (fa) is not different from the order of terminal IDs corresponding to CH1 to CH3 in the allocation table T2. If so, the operation ends.

(Action / Effect)
According to the base station 100 according to the present embodiment, the time slot allocating unit 404 is configured such that the terminals 10a to 10c having a smaller value indicating the variation period (fa) in the wireless communication between the base station 100 and the terminals 10a to 10c. The communication channels CH1 to CH3 having a short interval are allocated so that the interval from the uplink time slot to the downlink time slot becomes short (narrow).

  FIG. 9 shows a frame configuration in which the base station 100 according to the present embodiment assigns time slots to the terminals 10a to 10c. As shown in FIG. 10, the terminal 10a (the terminal 10a when the own terminal moves at high speed or the object X around the own terminal moves at high speed) is connected to the communication channel CH3 (uplink time slot) at the interval Δt3. Number U # 3 and downlink time slot D # 3) are changed to communication channel 1 (uplink time slot U # 1 and downlink time slot D # 1) having an interval Δt1 narrower than the interval Δt3. Therefore, the base station 100 according to the present embodiment, for example, in the radio communication with the terminal 10a, based on the uplink time slot signal received from the terminal 10a, for example, the downlink time for which the directivity is controlled for the terminal 10a. The signal in the slot can be transmitted before the terminal 10a or the object X existing around the terminal 10a moves greatly (high-speed movement) (before the fluctuation state of the propagation path changes rapidly). For this reason, it can reduce reliably that communication quality between terminal 10a deteriorates.

(First change example)
Next, focusing on differences from the above-described embodiment, the configuration of the base station 100 according to the first modification will be described. The base station 100 according to this modification is the same as the configuration of the base station 100 described above except for the configuration of the time slot allocation unit 404. Therefore, the configuration of the time slot allocation unit 404 will be described. The time slot allocation unit 404 of the base station 100 according to the present modification example has a predetermined threshold value (ρSH) determined in advance, and a value indicating the fluctuation cycle (fa) stored in the propagation path fluctuation table T1. When the value is smaller than the predetermined threshold value, the operations of Steps S1062 to S1063 described above are performed. The operations in steps S1062 to S1063 are not performed.

  When the fluctuation period (fa) stored in the propagation path fluctuation table T1 does not become smaller than the predetermined threshold, the time slot allocation unit 404 seems to have been implemented in the prior art for the terminals 10a to 10c. Are assigned time slots (for example, upstream time slot U # 1 and downstream time slot D # 1) with an interval Δt.

  According to the base station 100 according to the present modification example, the communication channel assignment is changed only when there are terminals 10a to 10c whose values indicating the fluctuation period (fa) are smaller than a predetermined threshold. The change frequency can be reduced as compared with the embodiment described above. Therefore, according to the base station 100 according to the present modification example, the terminal 10a to the terminal 10a to 10b having a small value indicating the variation period (fa) while minimizing the processing load when allocating communication channels (uplink and downlink time slots). When 10c exists, it is possible to suppress deterioration in communication quality with the terminals 10a to 10c.

(Second modification)
Next, focusing on differences from the above-described embodiment, the configuration of the base station 100 according to the third modification will be described. The base station 100 according to this modification is the same as the configuration of the base station 100 described above except for the configuration of the time slot allocation unit 404. Therefore, the configuration of the time slot allocation unit 404 will be described.

  The time slot allocating unit 404 according to this modified example uses the communication channel CH1 having the shortest (narrow) interval between the uplink time slot and the downlink time slot between the terminals 10a to 10c having higher mobility than a predetermined threshold. Use only for communication.

  Specifically, time slot allocating section 404 does not include communication channel CH1 in the resource map for transmission. Further, the time slot allocation unit 404 has a predetermined threshold (ρSH) determined in advance, and the fluctuation period (fa) stored in the propagation path fluctuation table T1 is smaller than the predetermined threshold (propagation path). For example, only when the terminal 10a exists, the uplink time slot number and the downlink time slot number of the communication channel CH1 in which the interval between the uplink time slot and the downlink time slot is the shortest for the terminal 10a. Is transmitted, and communication using the communication channel CH1 is performed with the terminal 10a.

  According to the base station 100 according to the present modification, the communication channel CH1 having the shortest interval between the uplink time slot and the downlink time slot is the terminal whose fluctuation cycle (fa) is smaller than the predetermined threshold (the propagation path fluctuation is large). Use only for 10a. Therefore, the operation of using the communication channel CH1 already, for example, changing the terminals 10b to 10c to other communication channels CH2 to CH3 becomes unnecessary, the processing load in the base station 100 can be reduced, and the moving terminal 10a It is possible to suppress the deterioration of communication quality between the two.

[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.

  In the embodiment described above, the base station 100 has been described as an example of the wireless communication apparatus according to the present invention, and the terminals 10a to 10c have been described as examples of the other apparatuses. However, the storage unit 402 illustrated in FIG. Each function such as the propagation path state detection unit 403 and the time slot allocation unit 404 may be arranged in a device other than the base station 100. For example, these functions can be arranged in a server that exists above the base station 100 in the wireless communication system. That is, the present invention can be applied to various apparatuses that perform communication by the TDMA / TDD system.

  In the above-described embodiment, the time slot allocation according to the fluctuation period (fa) of the propagation path has been described. However, time slot allocation according to communication quality (for example, FER) may be performed without using the fluctuation period (fa) of the propagation path. That is, the lower the communication quality, the shorter the uplink / downlink time slot interval is set. A terminal with low communication quality is stable against communication with a terminal with low communication quality because the terminal may be moving at high speed or an object existing around the terminal may be moving at high speed. As a result, it is possible to suppress degradation of communication quality by assigning uplink / downlink time slot intervals that can be accommodated for the purpose of optimization.

  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 the whole schematic figure which shows the base station and terminal which concern on 1st Embodiment of this invention. It is a block diagram of the base station which concerns on 1st Embodiment of this invention. It is a logic block block diagram in the signal control part of the base station which concerns on 1st Embodiment of this invention. It is a logic block block diagram in the control part of the base station which concerns on 1st Embodiment of this invention. It is a figure which shows the propagation path fluctuation | variation table memorize | stored in the base station which concerns on 1st Embodiment of this invention. It is a figure which shows the allocation table memorize | stored in the base station which concerns on 1st Embodiment of this invention. It is a figure which shows the resource map which concerns on 1st Embodiment of this invention. It is a sequence diagram of the communication method which concerns on 1st Embodiment of this invention. It is a flowchart figure of the communication method which concerns on 1st Embodiment of this invention. It is a figure which shows the flame | frame structure which allocated the time slot in communication with the base station and terminal which concern on this 1st Embodiment. It is a figure which shows the flame | frame structure which allocated the time slot in communication with the base station and terminal which concern on a prior art.

Explanation of symbols

  100: base station, 200: radio processing unit, 201 to 212: first radio unit to twelfth radio unit, 300: signal processing unit, 301 to 304: first signal control unit to fourth signal control unit, 400A, 400B : Control unit, 401: TDMA separation processing unit, 402: storage unit, 403: propagation path state detection unit, 404: time slot allocation unit, 405: TDMA multiple processing unit, 3101: coefficient calculation unit, 3201-3212: multiplication unit , 3301: synthesis unit, 3401: separation unit, 3501-3512: multiplication unit, fa: variation period, C1 to C3: variation period, A to D: point, L: frequency for communication, C100: wireless range, S101 to S108 : Step, S1061 to S1063: step, T1: propagation path fluctuation table, T2: allocation table, Δt1 to Δt3: interval, CH1 to C H3: communication channel, 10a to 10c: terminal, UE10a to 10c: terminal ID.

Claims (7)

A wireless communication device that uses a time division multiple access / time division duplex method in wireless communication with a plurality of other devices and controls a downlink signal based on an uplink signal,
A propagation path state detection unit for detecting a fluctuation state of a propagation path with the other apparatus based on a received radio signal from the other apparatus;
An assigning unit for assigning a pair of time slots to the other device;
The pair of time slots includes an upstream time slot that is a transmission period of the upstream signal and a downstream time slot that is a transmission time of the downstream signal,
The time width of the upstream time slot is different from the time width of the downstream time slot,
The order in the time series in the upstream time slot is equal to the order in the time series in the downstream time slot,
The wireless communication apparatus, wherein the assigning unit selects and assigns the pair of time slots based on a fluctuation state of the propagation path detected by the propagation path state detection unit. The propagation path state detection unit grasps a fluctuation period in which the state of the propagation path with the other device fluctuates based on the detected fluctuation state of the propagation path,
The assigning unit selects and assigns the pair of time slots according to the fluctuation period grasped by the propagation path state detecting unit,
The wireless communication apparatus according to claim 1. The assigning unit determines an order for the plurality of other devices according to the propagation state of the propagation path grasped by the propagation path state detection unit, and selects the pair of time slots based on the order. assign,
The wireless communication apparatus according to claim 1, wherein the wireless communication apparatus is a wireless communication apparatus. The allocating unit is configured so that the time difference between the uplink time slot and the downlink time slot becomes shorter as the other terminal having the smaller value indicating the fluctuation period of the grasped propagation path becomes shorter. Select and assign time slots,
The wireless communication device according to claim 2, wherein the wireless communication device is a wireless communication device.   The detection of a fluctuation state of the propagation path by the propagation path state detection unit is performed by detecting a fluctuation of a power value of a reception radio signal from the other device. Wireless communication device.   The wireless communication apparatus according to claim 2, wherein the detection of the fluctuation state of the propagation path by the propagation path state detection unit is performed by detecting Doppler fluctuation of the received radio signal. A communication method in a radio communication device that uses a time division multiple access / time division duplex method in radio communication with a plurality of other devices and controls a downlink signal based on an uplink signal,
Detecting a fluctuation state of a propagation path with the other device;
Assigning a pair of time slots to the other device,
The pair of time slots includes an upstream time slot that is a transmission period of the upstream signal and a downstream time slot that is a transmission time of the downstream signal,
The time width of the upstream time slot is different from the time width of the downstream time slot,
The order in the time series in the upstream time slot is equal to the order in the time series in the downstream time slot,
In the assigning step, the pair of time slots are selected and assigned based on the detected fluctuation state of the propagation path.
A communication method characterized by the above.

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