Details

Entitled wireless communication system, a base station, a terminal and a processing method

Technical field

[0001]

　The present invention relates to a radio communication system, a base station, a terminal and a processing method.

Background technique

[0002]

　Conventionally, LTE mobile communication such as (Long Term Evolution) and LTE-advanced is known. Moreover, by utilizing the unlicensed spectrum CA: a technology for performing (Carrier Aggregation carrier aggregation) it is known (e.g., Patent Document 1 see.).

CITATION

Patent Document

[0003]

Patent Document 1: Japanese Patent Publication No. 2014-500685

Summary of the Invention

Problems that the Invention is to Solve

[0004]

　However, licensing in a system using shared bandwidth, such as unnecessary band, for example, the signal transmitted from the Check the available bandwidth is determined, the plurality of terminals transmit radio signals overlap in time are assumed It has not been. Therefore, it is difficult multiplexed users in the frequency direction, there is a case where the user multiplexing can not improve the throughput of the uplink.

[0005]

　In one aspect, the present invention allows the user multiplexing uplink in a shared band, and an object thereof is to provide a radio communication system which can improve the throughput, the base station, a terminal and a processing method.

Means for Solving the Problems

[0006]

　To solve the above problems and achieve an object, according to one aspect of the present invention, in a wireless communication system sharing a predetermined band with another wireless communication system, a plurality of terminals connected to the base station the process for detecting a radio signal of the predetermined band starts, respectively, in common predetermined timing between the plurality of terminals, the wireless signal of the predetermined band by said processing state not detected among the plurality of terminals in common predetermined time sequential timing, the predetermined bandwidth to the wireless communication system that initiates each transmit a radio signal in the same band or different bands among the bands included, the base station, the terminal and processing methods have been proposed that.

Effect of the Invention

[0007]

　According to one aspect of the present invention, there is an effect that it is possible to allow user multiplexing uplink, to improve the throughput in the shared band.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]

[Figure 1A] Figure 1A is a diagram showing an example of a wireless communication system according to an embodiment.
FIG 1B] Figure 1B is a diagram showing an example of a flow of signals in the wireless communication system shown in Figure 1A.
FIG. 2 is a diagram showing an example of a band of Unlicensed Dobando.
FIG. 3 is a diagram showing an example of the timing of transmission and reception of the carrier sense and each signal.
[4] FIG. 4 is a diagram showing an example of a cell of a common offset notified by the base station.
[Figure 5A] Figure 5A is a diagram showing an example of a transmission start timing of each terminal.
[Figure 5B] Figure 5B is a diagram showing a modification of the transmission start timing of each terminal.
[6] FIG 6 is a flowchart illustrating an example of processing by the terminal.
[Figure 7A] Figure 7A is a diagram illustrating an example of a base station according to the embodiment.
[Figure 7B] Figure 7B is a diagram showing an example of signal flow in a base station shown in FIG. 7A.
[Figure 7C] Figure 7C is a diagram illustrating an example of a hardware configuration of the base station.
[FIG. 8A] Figure 8A is a diagram illustrating an example of a terminal according to the embodiment.
[Figure 8B] Figure 8B is a diagram illustrating an example of a signal flow in the terminal shown in Figure 8A.
[Figure 8C] Figure 8C is a diagram showing an example of a hardware configuration of the terminal.
FIG 9A] FIG 9A is a diagram illustrating an example of a base station according to a modification.
[FIG. 9B] FIG 9B is a diagram showing an example of signal flow in a base station shown in Figure 9A.
[10] FIG 10 is a diagram showing an example of signal flow in a terminal according to the modification.

DESCRIPTION OF THE INVENTION

[0009]

　With reference to the drawings, a wireless communication system according to the present invention, a base station, an embodiment of a terminal and a processing method will be described in detail.

[0010]

(Embodiment)
(a wireless communication system according to an embodiment)
　FIG. 1A is a diagram showing an example of a wireless communication system according to an embodiment. Figure 1B is a diagram showing an example of a flow of signals in the wireless communication system shown in Figure 1A. Figure 1A, 1B, the radio communication system 100 according to the embodiment includes a base station 110, the terminal 120 and 130, a.

[0011]

　Wireless communication system 100 is a system for sharing a predetermined band with another wireless communication system. Predetermined band is a band which is shared by a plurality of wireless communication system including a wireless communication system 100. As an example, a predetermined band is unlicensed Dobando (unlicensed band). The unlicensed Dobando, as one example, WLAN: ISM, which is used in (Wireless Local Area Network Wireless Local Area Network), etc. (Industry-Science-Medical) band (2.4 [GHz] band) and 5 [GHz ] band, and the like.

[0012]

　The base station 110 uses a predetermined bandwidth to be shared with another wireless communication system, wireless communication is performed between the terminal 120 and 130 to be connected to the base station 110 (own station). The carrier aggregation between the base station 110 includes a band for example the wireless communication system 100 (host system) is occupied, and the predetermined bandwidth to be shared with another wireless communication system includes a terminal 120 and 130 using it may be carried out wireless communication by.

[0013]

　In the wireless communication system 100, for example, terminal 120 and 130 user multiplexing uplink for transmitting a radio signal to the base station 110 at the same time is carried out by a predetermined band. In this case, the terminal 120 transmits a radio signal to the base station 110 through respective different bands of each band included in a predetermined band. Further, for example, multi-user MIMO: When using the (Multi User Multiple Input Multiple Output multiuser multiple-input multiple-output) terminal 120 and 130 transmits a radio signal to the base station 110 by the same band.

[0014]

　The base station 110 includes a control unit 111, a receiving unit 112, a. Control unit 111 to the terminal 120 and 130 transmits a parameter for calculating a common predetermined timing between the terminal 120 and 130. Receiving unit 112 receives each radio signal transmitted by the terminal 120 and 130. For example, the receiving unit 112 receives a data signal addressed to the own station included in each radio signal transmitted by the terminal 120 and 130.

[0015]

　Terminal 120 includes a detection unit 121, a transmission unit 122, a. Here, a description will be given of the configuration of the terminal 120, the same as the configuration is also the terminal 120 of the terminal 130. Detector 121, a process for detecting a radio signal in a predetermined band starts at the common predetermined timing between the terminal 120 and 130. Thus, it is possible to match the timing of the terminal 120, 130 to start the processing for detecting a radio signal in a predetermined band. Predetermined timing may be for example base station 110 is calculated based on the parameters transmitted to the terminal 120 and 130. Detector 121 notifies the detection result to the transmitting unit 122.

[0016]

　Transmitter 122, based on the detection result notified from the detection unit 121, a state in which the radio signal in a predetermined band is not detected at the timing when successive predetermined time, corresponding to the local terminal of each band included in a predetermined band It starts transmission of radio signals in the band. Predetermined time is a common time between the terminal 120 and 130. Thus, the terminal 120 and 130 can be timed to start sending wireless signals.

[0017]

　FIG. 1A, according to the configuration shown in FIG. 1B, a predetermined timing by the terminal 120, 130, initiates a free detection of shared bandwidth with other wireless communication system, a predetermined time to transmit a radio signal, it can be matched. Thus, the combined transmission timing of the radio signal at the terminal 120 and 130, it is possible to avoid transmission collisions between terminals 120 and 130 in the shared bandwidth. Therefore, it becomes possible spatial directions of the multiplexed users by user multiplexing or multi-user MIMO in the frequency direction of the uplink in a shared band, it is possible to improve the throughput.

[0018]

　detection of radio signals in a predetermined band by the detector 121, for example, CCA for detecting a free carrier in a predetermined band: A (Clear Channel Assessment clear channel assessment), for example, carrier sense it is.

[0019]

　For example, detection of a radio signal in a predetermined band is a process for detecting a radio signal by detecting a radio wave received power (reception energy), and compares the detected reception power and the predetermined power in a predetermined band. Or, the detection of the radio signal in a predetermined band can be a process for detecting a radio signal by detecting a predetermined pattern of a radio signal (e.g., preamble) based on the radio wave in a predetermined band.

[0020]

　The processing for detecting the radio signal of a predetermined band, for example, a process for detecting a radio signal in all of the predetermined band. Or, a process of detecting a radio signal in a predetermined band, of the predetermined band, the terminal itself may be a process for detecting a radio signal in only band for transmitting a radio signal.

[0021]

　Although the terminal 120, 130 based on parameters transmitted from the base station 110 has been described structure for calculating the predetermined timing, the base station 110 may not transmit the parameter. In this case, the terminal 120 and 130, for example, can calculate the predetermined timing based on information shared between the terminal 120 and 130. Also, in this case, the base station 110 may not include a control unit 111.

[0022]

　Information shared between the terminal 120 and 130 can be, for example, information including identification information of the cell of the base station 110 (e.g., cell ID). Further, the information to be shared between the terminal 120 and 130 may be information including identification information of the sub-frame to perform the process of detecting a radio signal (e.g. subframe number).

[0023]

(Band Unlicensed Dobando)
　FIG. 2 is a diagram showing an example of a band of Unlicensed Dobando. In the wireless communication system 100, unlicensed Dobando 200 is used for example. In the example shown in FIG. 2, unlicensed Dobando 200 are band of 20 [MHz] width.

[0024]

　Unlicensed Dobando 200 is a band which is shared between the radio communication system 100 and other systems. Other systems, such as WLAN or the like wireless communication system 100 with different LTE or LTE-A radio communication system.

[0025]

　The unlicensed Dobando 200, sub-band # 1, includes a # 2. Hereinafter, the base station 110 allocates a sub-band # 1 for uplink transmission of the terminal 120, the case where assigned subband # 2 for uplink transmission of the terminal 130.

[0026]

(The timing of transmission and reception of the carrier sense and each signal)
　3 is a diagram showing an example of the timing of transmission and reception of the carrier sense and each signal. 3, the horizontal axis (t) represents time.

[0027]

　Reference timing 301 is a common reference timing in the cell of the base station 110. In the example shown in FIG. 3, the reference timing 301, base station 110 is the sub-band # 1, a timing for transmitting and receiving signals in # 2. However, the reference timing 301, base station 110 is the sub-band # 1, may be different timing as for transmitting and receiving signals in # 2.

[0028]

　Cell common offset 302 is a common offset in the cell of the base station 110, a parameter for calculating the reference timing 301 (predetermined timing). In the example shown in FIG. 3, the cell common offset 302 is the offset between the reference timing 301 and carrier sense start timing 303.

[0029]

　Carrier sense start timing 303 is timing when the terminal 120, 130 to start the carrier sense. The carrier sense start timing 303, the reference timing 301, a cell common offset 302, a timing that is uniquely determined from.

[0030]

　In the example shown in FIG. 3, the carrier sense start timing 303 is a timing going back from the reference timing 301 only cell common offset 302. However, the carrier sense start timing 303 may be a timing advanced by the cell common offset 302, for example, from reference timing 301.

[0031]

　Specified idle time 304 is a reference time for determining the band is empty. For example, the terminal 120 performs carrier sense, when idle for specified idle time 304 (I) are continuous, it is determined that the band is empty.

[0032]

　Transmission start scheduled timing 305 is timing when the terminal 120 and 130 when it is determined that the band is vacated by carrier sense starts transmission of a radio signal. For example, transmission start scheduled timing 305 is an advanced timing from the carrier sense start timing 303 by the specified idle time 304.

[0033]

　In the example shown in FIG. 3, terminal 120, the carrier sense is started in the carrier sense start timing 303, since the idle prescribed idle time 304 (I) are continuous, the transmission of the radio signal at the transmission start scheduled timing 305 It has started. In this case, the terminal 120 first sends a dummy signal 311, and then transmits the data signal 312.

[0034]

　Similarly, terminal 130, the carrier sense is started in the carrier sense start timing 303, since the idle prescribed idle time 304 (I) are continuous, and starts transmission of radio signals in the transmission start scheduled timing 305 . In this case, the terminal 130 first transmits a dummy signal 321, and then transmits the data signal 322.

[0035]

　This makes it possible to adjust the reception timing of the data signals 312 and 322 at base station 110 in the reference timing 301. Further, between sending the scheduled start time 305 until the start of transmission of the data signals 312 and 322, another communication apparatus can be prevented from transmitting a radio signal (interrupt). Other communication devices, for example, wireless communication device of the communication system 100 differs from wireless communication system.

[0036]

　In the example shown in FIG. 3, the case has been described where the terminal 120 and 130 transmits a dummy signal 311 and 321 respectively, the terminal 120 may transmit a preamble in place of the dummy signal 311, 321. Each preamble terminal 120, 130 is transmitted as a radio signal of a predetermined pattern, for example, the preamble of each of the data signals 312 and 322.

[0037]

　In the example shown in FIG. 3, it has been described a case cell common offset 302 is the offset between the reference timing 301 and carrier sense start timing 303. However, not limited to this, the cell common offset 302 may be offset between the example and the reference timing 301 and transmission start scheduled timing 305.

[0038]

　In this case, the terminal 120 calculates a timing going back from the reference timing 301 only cell common offset 302 as the transmission start scheduled timing 305. Then, the terminal 120 and 130, a timing going back by a defined idle time 304 from the transmission start scheduled timing 305 calculated calculated as a carrier sense start timing 303, it starts carrier sense.

[0039]

　The cell common offset 302, for example, may be a different length for each predetermined period (for example, every each and a plurality of sub-frame subframe). Thus, for example, it can be a terminal 120, 130 by the same timing as the communication device of the adjacent cells to avoid a collision occurs in succession by sending a radio signal.

[0040]

　The cell common offset 302 may be offset that is determined based on the cell to a unique value of the base station 110 (e.g., cell number). This can suppress the collision of the communication device of the adjacent cell.

[0041]

　For example, the base station 110 determines the cell common offset 302 based on at least one of the sub-frame number and cell number. As an example, the base station 110 determines the cell common offset 302 based on the following equation (1).

[0042]

[Number 1]

[0043]

　In the above (1), offset is the cell common offset 302 of the decision object. c (i) is a pseudo-random number sequence. u, v, w, L is a constant which is previously defined in the radio communication system 100. The c (i), for example, can be used Gold sequence, which is defined in the 3GPP TS36.211. For example, c (i), can be used the following formula (2).

[0044]

[Number 2]

[0045]

　In equation (2), x 1 (n), x 2 each (n) is a sequence called m-sequence, the initial value is given by the following equation (3).

[0046]

[Number 3]

[0047]

　For example, base station 110, v, w, c init to at least one of, by substituting the sub-frame number, it is possible to determine the cell common offset 302 based on the subframe number. Or, the base station 110, v, w, c init to at least one of, by substituting the cell number, it is possible to determine the cell common offset 302 based on the cell number.

[0048]

　Or, the base station 110, v, w, c init to at least one of, by substituting the sub-frame number and cell number, it is possible to determine the cell common offset 302 based on the subframe number and cell number. For example, base station 110 in the above (1) to (3), v substitutes the sub-frame number in, c init substitutes cell number, w = 0, L = 64 , u = 12 as the cell it is possible to determine the common offset 302.

[0049]

　The cell common offset 302 may be offset that is determined based on a random number. Thus, for example, it can be a terminal 120, 130 by the same timing as the communication device of the adjacent cells to avoid a collision occurs in succession by sending a radio signal. For example, the base station 110 may determine a cell common offset 302 by the following equation (4).

[0050]

　Cell common offset = a × unit time ... (4)

[0051]

　In the above (4), a is {0,1, ... A} is a random number that is randomly selected from. A is a value less than the subframe length in the wireless communication system 100.

[0052]

(Notification of the cell common offset by the base station)
　FIG. 4 is a diagram showing an example of a cell common offset notification by the base station. As shown in FIG. 4, for example, base station 110 notifies the cell common offset relative to terminals 120 and 130 connected to the own cell. The notification of the cell common offset, for example, PDCCH (Physical Downlink Control Channel: PDCCH) can be used a common control channel of the downlink, such as.

[0053]

　Further, the notification of the cell common offset, for example, RRC: may be used control information (Radio Resource Control Radio Resource Control) upper layer, such as. Further, the notification of the cell common offset, e.g. PBCH: may be used broadcast channel, such as (Physical Broadcast Channel physical broadcast channel).

[0054]

　Further, base station 110, by notifying a possible calculation parameters cell common offset to the terminal 120 and 130 at terminal 120 and 130, the cell common offset may be indirectly notified to the terminal 120 and 130. In this case, the terminal 120 and 130, calculates a cell common offset based on the transmitted parameter from the base station 110.

[0055]

(Transmission start timing of each terminal)
　FIG. 5A is a diagram showing an example of a transmission start timing of each terminal. In Figure 5A, the description thereof is omitted are denoted by the same reference numerals similar to those depicted in FIG. Subframe boundaries 511 and 512 is the boundary of a subframe in the reception of the down link from the base station 110 to terminal 120. Subframe boundary 521 is the boundary of a subframe in the reception of the down link from the base station 110 to terminal 130.

[0056]

　For example, the base station 110 is transmitting the same timing a downlink signal to the terminal 120 (reference timing 301). In contrast, the propagation delay T1 between the base station 110 and the terminal 120, the propagation delay T2 between the base station 110 and the terminal 130, the difference in the sub-frame boundary 511, 512 and the sub-frame boundaries 521 , a different timing from the 522.

[0057]

　For example the sub-frame boundary 512 is a timing advanced by the propagation delay T1 from the reference timing 301. Data signal transmission start timing 531 is a timing at which the terminal 120 starts the transmission of the data signal 312 is a timing going back by the propagation delay T1 from the reference timing 301.

[0058]

　Terminal 120 can identify a timing going back by the propagation delay T1 × 2 subframes boundary 512 as a data signal transmission start timing 531. Then, terminal 120 may initiate the transmission of the data signal 312 at the data signal transmission start timing 531, can be combined with the reference timing 301 the reception timing of data signal 312 at base station 110.

[0059]

　The sub-frame boundary 522 is a timing advanced by the propagation delay T2 from the reference timing 301. Data signal transmission start timing 532 is a timing at which the terminal 130 starts transmitting the data signal 322 is a timing going back by the propagation delay T2 from the reference timing 301. Terminal 130 can identify a timing going back by the propagation delay T2 × 2 subframes boundary 522 as a data signal transmission start timing 532. Then, the terminal 130, by starting transmission of the data signal 322 at the data signal transmission start timing 532, can be combined with the reference timing 301 the reception timing of data signal 322 at base station 110.

[0060]

　The terminal 120, the propagation delay T1 × 2, Timing Advance received from the base station 110: may be identified based on (TA Timing Advance). For example, base station 110, the propagation delay T1 between the base station 110 and the terminal 120 is measured, and sends the timing advance indicating twice the value of the propagation delay T1 measured to the terminal 120. In contrast, the terminal 120 is able to determine the value of timing advance received from the base station 110 as the propagation delay T1 × 2.

[0061]

　The terminal 130, the propagation delay T2 × 2, can be identified based on the timing advance to be received from the base station 110. For example, base station 110, the propagation delay T2 between the base station 110 and the terminal 130 is measured, and sends the timing advance indicating twice the value of the propagation delay T2 measured to the terminal 130. In contrast, the terminal 130 is able to determine the value of timing advance received from the base station 110 as the propagation delay T2 × 2.

[0062]

　Also, the period in which the terminal 120 transmits the dummy signal 311, for example, be a period from the transmission start scheduled timing 305 to the data signal transmission start timing 531. Also, the period in which the terminal 130 transmits the dummy signal 321, for example, be a period from the transmission start scheduled timing 305 to the data signal transmission start timing 532.

[0063]

　Figure 5B is a diagram showing a modification of the transmission start timing of each terminal. 5B, the description thereof is omitted are denoted by the same reference numerals similar to those depicted in FIG. 5A. In Figure 5B, the case of using the multi-user MIMO. In this case, the terminal 120, 130 can use the same band of Unlicensed Dobando 200.

[0064]

　For example, the base station 110 allocates a sub-band # 1 for uplink transmission of the terminal 120, the case where assigned subband # 1 to transmit the uplink of the terminal 130. In this case, as shown in Figure 5B, terminal 130, in sub-band # 1, it performs carrier sense, and transmits a dummy signal 321 and data signal 322. Further, base station 110, the subband # 1, to receive the dummy signal 321 and data signal 322 from the terminal 130.

[0065]

(Processing by the terminal)
　FIG. 6 is a flowchart illustrating an example of processing by the terminal. Here will be described the processing by the terminal 120, the same applies to the processing by the terminal 130. Terminal 120, when transmitting the uplink data signal, performing the steps shown in FIG. 6, for example.

[0066]

　First, the terminal 120 calculates a carrier sense start timing based on a cell common offset (step S601). Then, the terminal 120 waits until the carrier sense start timing calculated in the step S601 (step S602).

[0067]

　Then, the terminal 120, the initialized (m = 0) m (step S603). m is the count for counting the number of executions of the carrier sense unit time. Then, the terminal 120, m to determine whether equal to M-N (step S604). M is a cell-common offset. N is a specified idle time. Also, the unit of M and N are both units of the carrier sense time.

[0068]

　In step S604, the case where m is equal to M-N (step S604: Yes), even if the detected idle channels through the carrier sense, can not start the transmission of the data signal until the next reference timing 301 of the base station 110 it can be determined that. In this case, the terminal 120 ends the series of processes.

[0069]

　In step S604, the case where m is not equal to M-N (step S604: No), the terminal 120 initializes n (n = 0) (step S605). n is the count value for counting the number of times the idle state of the channel (bandwidth) is continuously detected by carrier sense.

[0070]

　Then, the terminal 120 performs carrier sense unit time (step S606). The terminal 120 increments the m (m = m + 1) to. Then, the terminal 120, based on the carrier sense result of step S606, the channel is determined whether an idle state (step S607). Incidentally, the channel of interest to determine whether idle or in step S607, the example may be only subbands that terminal 120 is assigned (subbands # 1), a total of Unlicensed Dobando 200 it may be.

[0071]

　In step S607, the case where the channel is not idle (step S607: No), the terminal 120 returns to step S604. If the channel is idle (step S607: Yes), the terminal 120 increments n (n = n + 1) (step S608).

[0072]

　Then, the terminal 120, n determines whether equal to N (step S609). If n is not equal to N (step S609: No), the terminal 120 returns to step S606. If n is equal to N (step S609: Yes), the terminal 120 transmits a signal in the uplink (step S610), and ends the series of processes. In step S610, the example, terminal 120, as shown in FIG. 3, first sends a dummy signal, and then transmits the data signal to.

[0073]

　In the example shown in FIG. 6 has been described process of calculating the carrier sense start timing when the terminal 120 transmits a signal, the terminal 120 may contact previously calculated carrier sensing start timing based on the cell common offset It can have.

[0074]

(Base station according to the embodiment)
　Figure 7A is a diagram illustrating an example of a base station according to the embodiment. Figure 7B is a diagram showing an example of a flow of signals in a base station shown in FIG. 7A. Figure 7A, as shown in FIG. 7B, the base station 110 includes an antenna 701, an RF unit 702, an uplink baseband signal processing unit 703, a propagation delay measurement section 704, an uplink transmission timing control unit 705, It includes a downlink baseband signal generating unit 706, a.

[0075]

　Antenna 701, and outputs it to the RF section 702 receives a radio signal transmitted from the terminal 120 and 130. The antenna 701 wirelessly transmits a signal output from the RF unit 702 to the terminal 120, 130. The antenna 701 may be a plurality of antennas is not limited to one antenna. For example, when performing multi-user MIMO, the antenna 701 may be a plurality of antennas corresponding to the multi-user MIMO.

[0076]

　RF unit 702 performs RF signal reception processing of uplink output from the antenna 701. The RF reception processing by RF section 702, for example, amplification, RF: frequency conversion from (Radio Frequency RF) band to a baseband band, and the like conversion from an analog signal to a digital signal. RF unit 702 outputs the signal subjected to RF reception processing to the uplink baseband signal processing section 703.

[0077]

　Also, RF unit 702 performs RF transmission processing of downlink signals output from the downlink baseband signal generating unit 706. The RF transmission processing by the RF unit 702, for example, conversion from a digital signal to an analog signal, a frequency conversion to the RF band from the baseband includes amplification and the like. RF unit 702 outputs the signal subjected to RF transmission processing to the antenna 701.

[0078]

　Uplink baseband signal processing unit 703 performs baseband signal processing for the uplink signal outputted from the RF unit 702. Then, the uplink baseband signal processing unit 703 outputs the measurement signal included in the data obtained by the baseband signal processing to the propagation delay measurement unit 704. Uplink baseband signal to the measurement signal output from the processing section 703 to the propagation delay measurement section 704, for example, the uplink from the terminal 120,130 RS (Reference Signal: reference signal) and RACH (Random Access Channel: Random Access channel), and the preamble.

[0079]

　Propagation delay measurement section 704, based on the measuring signal outputted from the uplink baseband signal processing unit 703 measures the respective propagation delay between the base station 110 and the terminal 120 and 130. For example, the propagation delay measuring unit 704, based on the RS and RACH preamble transmitted from the terminal 120, to measure the propagation delay between the base station 110 and terminal 120. Further, the propagation delay measuring unit 704, based on the RS and RACH preamble transmitted from the terminal 130, to measure the propagation delay between the base station 110 and terminal 130.

[0080]

　Then, the propagation delay measurement section 704, for each of the terminals 120 and 130, and outputs the timing advance based on the propagation delay value measured to the downlink baseband signal generating unit 706. Timing advance is information indicating twice the propagation delay, for example it has been determined.

[0081]

　Uplink transmission timing control unit 705 controls the transmission timing in the uplink from the terminal 120, 130 to the base station 110. For example, uplink transmission timing control unit 705 determines the cell common offset between the carrier sense start timing and the reference timing, and notifies the determined cell common offset to the downlink baseband signal generating unit 706. Cell common offset determined uplink transmission timing control unit 705 is, for example, a cell common offset 302 shown in FIG.

[0082]

　Downlink baseband signal generating unit 706 generates the baseband downlink signal to the terminal 120, 130 from the base station 110. The signal downlink baseband signal generating unit 706 generates includes output from the propagation delay measurement section 704 the timing advance and notified cell common offset from the uplink transmission timing control section 705. Downlink baseband signal generating unit 706 outputs the generated signal to the RF unit 702.

[0083]

　Figure 1A, control unit 111 shown in FIG. 1B, for example an antenna 701, RF unit 702 can be realized by the uplink transmission timing control unit 705 and a downlink baseband signal generating unit 706. Figure 1A, the receiving unit 112 shown in FIG. 1B, can be realized by, for example, an antenna 701, RF section 702 and uplink baseband signal processing section 703.

[0084]

　7C is a diagram showing an example of a hardware configuration of the base station. Figure 7A, the base station 110 shown in FIG. 7B may be implemented by the communication device 730 shown in FIG. 7C, for example. Communication device 730 includes a processor 731, a main memory 732, an auxiliary storage device 733, a network interface 734, a radio 735, an antenna 736, a. Processor 731, main memory 732, an auxiliary storage device 733, a network interface 734 and radio 735 are connected by a bus 739.

[0085]

　The processor 731 governs overall control of the communication device 730. The processor 731, e.g., CPU: can be realized by (Central Processing Unit). Main memory 732, for example, is used as a work area of ​​the processor 731. Main memory 732, for example, RAM: can be realized by (Random Access Memory).

[0086]

　The auxiliary storage device 733 is, for example, a nonvolatile memory such as a magnetic disk, an optical disk, a flash memory. The auxiliary storage device 733, various programs for operating the communication device 730 are stored. Program stored in the auxiliary storage device 733 is executed by the processor 731 is loaded into the main memory 732.

[0087]

　Network interface 734 is, for example, is a communication interface for performing communication with an external communication device 730 by wired or wireless (e.g. host device or the core network of base stations 110). Network interface 734 is controlled by the processor 731.

[0088]

　Radio 735 uses the antenna 736 is a communication interface for performing communication with another communication device by a wireless (e.g., terminal 120, 130). Radio 735 is controlled by the processor 731.

[0089]

　Figure 7A, the antenna 701 shown in FIG. 7B may be implemented by, for example, an antenna 736. Figure 7A, RF unit 702 shown in FIG. 7B, for example, can be implemented by radio 735.

[0090]

　Figure 7A, the uplink baseband signal processing unit 703 shown in FIG. 7B, the propagation delay measuring unit 704, an uplink transmission timing control unit 705 and a downlink baseband signal generating unit 706 may be realized by, for example, the processor 731 .

[0091]

(According terminals to the embodiment)
　Figure 8A is a diagram illustrating an example of a terminal according to the embodiment. Figure 8B is a diagram illustrating an example of a signal flow in the terminal shown in Figure 8A. Figure 8A, but in FIG. 8B to describe the configuration of the terminal 120, the same applies to the configuration of the terminal 130.

[0092]

　Figure 8A, as shown in FIG. 8B, the terminal 120 includes an antenna 801, an RF unit 802, the downlink baseband signal processing section 803, an uplink transmission timing control unit 804, an uplink baseband signal generating unit 805 and, equipped with a.

[0093]

　Antenna 801, and outputs it to the RF section 802 receives a radio signal transmitted from the base station 110. The antenna 801 wirelessly transmits a signal output from the RF unit 802 to the base station 110.

[0094]

　RF unit 802 performs RF signal reception processing of uplink output from the antenna 801. The RF reception processing by RF section 802, for example, amplification, frequency conversion from the RF band to the baseband, and the like conversion from an analog signal to a digital signal. RF unit 802 outputs the signal subjected to RF reception process to the downlink base band signal processing unit 803.

[0095]

　Also, RF unit 802 performs RF transmission processing of an uplink signal which is output from the uplink baseband signal generating unit 805. The RF transmission processing by the RF unit 802, for example, conversion from a digital signal to an analog signal, a frequency conversion to the RF band from the baseband includes amplification and the like. RF unit 802 outputs the signal subjected to RF transmission processing to the antenna 801.

[0096]

　Downlink baseband signal processing unit 803 performs baseband signal processing for a downlink signal outputted from the RF unit 802. Then, the downlink baseband signal processing unit 803 outputs the control information obtained by the baseband signal processing to the uplink transmission timing control section 804.

[0097]

　The control information output from the downlink baseband signal processing unit 803 to the uplink transmission timing control unit 804, for example, a downlink reception timing, timing advance from the base station 110, such as cell-common offset from the base station 110 information is included. Downlink reception timing is, for example, timing of subframe boundaries 511, 512 shown in Figure 5A. Timing advance is information indicating twice the propagation delay T1, for example shown in Figure 5A. Cell common offset, for example 3, is a cell common offset 302 shown in Figure 5A.

[0098]

　Uplink transmission timing control unit 804, based on control information output from the downlink baseband signal processing unit 803, determines a start timing and an uplink transmission start timing of the carrier sense.

[0099]

　Start timing of the carrier sense for determining the uplink transmission timing control unit 804 is, for example, a carrier sense start timing 303 shown in Figure 5A. For example, uplink transmission timing control section 804 determines a sub-frame boundary based on the downlink reception timing, and the propagation delay indicated by the timing advance, and the cell common offset, the carrier sense start timing based on. The uplink transmission timing controlling section 804 notifies the determined carrier sense start timing to the uplink baseband signal generating unit 805.

[0100]

　Transmission start timing uplink transmission timing control unit 804 is determined, for example, data signal transmission start timing 531 shown in Figure 5A. For example, uplink transmission timing control section 804 determines a sub-frame boundary based on the downlink reception timing, and the propagation delay indicated by the timing advance, the data signal transmission start timing based on. The uplink transmission timing controlling section 804 notifies the determined data signal transmission start timing to the uplink baseband signal generating unit 805.

[0101]

　Uplink baseband signal generating unit 805, based on each timing notified from the uplink transmission timing control unit 804, and generates the baseband signal of the control and uplink carrier sense. Then, the uplink baseband signal generating unit 805 outputs the generated signal to the RF unit 802.

[0102]

　For example, the uplink baseband signal generating unit 805 controls the RF unit 802 to perform carrier sense by the carrier sense start timing notified from the uplink transmission timing control section 804. Then, the uplink baseband signal generating unit 805, the carrier sense result, the specified idle time (specified idle time 304 shown in FIG. 5A) by the idle state is detected, starts transmission of a radio signal.

[0103]

　For example, the uplink baseband signal generating unit 805 first transmits a dummy signal (dummy signal 311 shown in FIG. 5A). Then, the uplink baseband signal generating unit 805 transmits the data signal (data signal 312 shown in FIG. 5A) by the notification data signal transmission start timing from the uplink transmission timing control section 804.

[0104]

　Figure 1A, the detection unit 121 and the transmitter 122 shown in FIG. 1B, for example an antenna 801, RF unit 802 can be realized by the uplink transmission timing control unit 804 and an uplink baseband signal generating unit 805.

[0105]

　Figure 8C is a diagram showing an example of a hardware configuration of the terminal. Figure 8A, the terminal 120 shown in FIG. 8B, can be implemented by the communication device 830 shown in FIG. 8C, for example. Communication device 830 includes a processor 831, a main memory 832, an auxiliary storage device 833, a user interface 834, a radio 835, an antenna 836, a. Processor 831, main memory 832, an auxiliary storage device 833, user interface 834 and radio 835 are connected by a bus 839.

[0106]

　The processor 831 governs overall control of the communication device 830. The processor 831 may be implemented by, for example CPU. Main memory 832, for example, is used as a work area of ​​the processor 831. Main memory 832 may be implemented by, for example, RAM.

[0107]

　The auxiliary storage device 833 is, for example, a nonvolatile memory such as a magnetic disk, an optical disk, a flash memory. The auxiliary storage device 833, various programs for operating the communication device 830 are stored. Program stored in the auxiliary storage device 833 is executed by the processor 831 is loaded into the main memory 832.

[0108]

　The user interface 834 includes, for example, and input devices for accepting an operation input from a user, and an output device for outputting information to the user. Input devices, for example, can be implemented by a key (e.g., a keyboard) or a remote controller. Output device can be implemented by, for example, a display or a speaker. It is also possible to achieve input and output devices, such as by a touch panel. The user interface 834 is controlled by the processor 831.

[0109]

　Radios 835 using the antenna 836 is a communication interface for performing communication with another communication apparatus by radio (e.g. base station 110). Radio 835 is controlled by the processor 831.

[0110]

　Figure 8A, the antenna 801 shown in FIG. 8B, can be implemented by, for example, an antenna 836. Figure 8A, RF unit 802 shown in FIG. 8B, for example, can be implemented by radio 835. Figure 8A, the downlink shown in FIG. 8B baseband signal processing unit 803, an uplink transmission timing control unit 804 and an uplink baseband signal generating unit 805 may be realized by, for example, the processor 831.

[0111]

(Wireless modification of the communication system)
　the base station 110 has been described configuration for notifying the cell common offset to the terminal 120, the base station 110 may be configured not to notify the cell common offset to the terminal 120 and 130. In this case, the terminal 120 and 130, for example, calculates the cell common offset using the parameters that are commonly recognized in the cell of the base station 110. Thus, the base station 110 without notifying the cell common offset to the terminal 120, 130 may be terminal 120, 130 to calculate the common cell common offset.

[0112]

　Figure 9A is a diagram showing an example of a base station according to a modification. Figure 9B is a diagram showing an example of a flow of signals in a base station shown in Figure 9A. Figure 9A, in FIG. 9B, FIG. 7A, the same parts as those depicted in FIG. 7B will be omitted with the same reference numerals. Figure 9A, as shown in FIG. 9B, the base station 110 according to the modified example, FIG. 7A, in the configuration shown in FIG. 7B, may be configured to omit the uplink transmission timing control section 705.

[0113]

　Figure 10 is a diagram showing an example of signal flow in a terminal according to the modification. 10, FIG. 8A, the same parts as those depicted in FIG. 8B is omitted with the same reference numerals. Structure of the terminal 120 according to the modified example is the same as that of the terminal 120 shown in Figure 8A. However, as shown in FIG. 10, the terminal 120 according to the modification are not include cells common offset control information output from the downlink baseband signal processing unit 803 to the uplink transmission timing control section 804.

[0114]

　Uplink transmission timing control unit 804, for example based on at least one of the sub-frame number and cell number, it calculates a cell common offset. Thus, the terminal 120 and 130 calculates the same cell common offset, it is possible to match the transmission timing of the radio signal terminals 120 and 130.

[0115]

　As described above, a wireless communication system, a base station, according to the terminal and a processing method, it is possible to allow the user multiple uplink in a shared band, to improve the throughput.

[0116]

　For example, conventionally, in LTE, in order to cope with increased traffic, by using the unlicensed band, it has been proposed to perform data offloading from dedicated band (Licensed band). Unlicensed band, for example, is referred to as unlicensed Dobando (Unlicensed band) or shared bandwidth (Shared band).

[0117]

　For example, to send the control information such as response signal (ACK / NACK) with dedicated band, Licensed-Assisted Carrier Aggregation method for transmitting data in unlicensed Dobando has been studied.

[0118]

　In unlicensed Dobando, in addition to the coexistence between LTE-u systems to coexist with other wireless systems, such as WLAN it is determined. In Japan and Europe Radio Law, before transmitting a radio signal, the radio channel is not being used by other wireless systems (in idle state) it is required to be confirmed by the carrier sense that.

[0119]

　In a WLAN has been put to practical use in the unlicensed Dobando, one user (station) is using all the bandwidth, user multiplexing in the time direction is performed. In contrast, LTE is that has been practiced in the license Dobando, not only the time direction, a user multiplexing is performed in the frequency direction. Further it may be performed also spatial direction of user multiplexing by MIMO.

[0120]

　That is, In LTE, but user multiplexing is performed in the same band, not realizing the method has been established for uplink transmission in unlicensed Dobando. For example, a description will be given of a case of performing random backoff (Random Backoff) Verify the unused at prescribed idle time for each terminal (idle state) as WLAN. In this case, the back-off period is long terminal becomes case not be able to send a radio signal to a radio signal will be detected by the carrier sense from a short terminal occurs.

[0121]

　For example, the terminal if the carrier sensing at the full bandwidth of Unlicensed Dobando (e.g. 20 [MHz] width), the detection is performed, including sub-band other than the scheduled terminal performs transmission. Therefore, likely to be determined channel is busy by a radio signal other terminals transmitted in another sub-band, is the case not be able to send radio signals generated.

[0122]

　Further, even when a terminal performs carrier sense only in sub-band of the plan to the transmission of radio signals, for leakage power another terminal caused by the radio signal transmitted by the neighboring subbands, determines the channel busy there is a case to be. This makes the case occurs not send radio signals.

[0123]

　In the case of using a multi-user MIMO in order to perform spatial multiplexing in the same bandwidth, may channel is determined to be busy with the terminal of the signal multiplexing opponent becomes case occurs not send radio signals.

[0124]

　In contrast, according to the embodiment described above, for example, for each terminal in the same cell can be made to the transmission start time of the uplink is the same. For example, by determining the transmission start timing of the carrier sense start timing and radio signals based on a common offset from the reference timing of each cell may transmit start time of the uplink is made to be the same.

[0125]

　Thus, in the unlicensed Dobando, performs carrier sense for each terminal, the transmission timing of the radio signal in each terminal can be the same. Therefore, it is possible to allow user multiplexing uplink in the same cell, to improve the throughput.

DESCRIPTION OF SYMBOLS

[0126]

　100 wireless communication system
　110 base station
　111 the control unit
　112 receiving unit
　120 and 130 the terminal
　121 detecting unit
　122 transmitting unit
　200 Unlicensed Dobando
　301 reference timing
　302 cell common offset
　303 carrier sense start timing
　304 defined idle time
　305 transmits the scheduled start time
　311, 321 dummy signal
　312, 322 data signals
　511,512,521,522 subframe boundaries
　531 and 532 data signal transmission start timing
　701,736,801,836 antenna
　702, 802 RF unit
　703 and 803 link the baseband signal processing unit
　704 propagation delay measuring unit
　705,804 link transmission timing control unit
　706,805 link baseband signal generation unit
　730,830 communication device
　731,831 processors
　732,8 32 main storage device
　733,833 auxiliary storage device
　734 network interface
　735,835 radios
　739,839 bus
　834 User Interface

The scope of the claims

[Claim 1]

　In wireless communication systems sharing a predetermined band with another wireless communication system,
　a base station,
　a plurality of terminals connected to the base station, a process for detecting a radio signal of the predetermined band, said plurality each starts at a common predetermined timing between the terminal, the common predetermined time sequential timing between the radio signals of the predetermined band by said processing state undetected said plurality of terminals, included in said predetermined band , said plurality of terminals to start sending radio signals in the same band or different bands of each band respectively
　a wireless communication system, which comprises a.

[Claim 2]

　Each of the plurality of terminals, calculates a timing at which a radio signal from the base station receives the own terminal, and information indicating a propagation delay between the base station and its own terminal, the predetermined timing based on the wireless communication system according to claim 1, in calculated the predetermined timing, characterized in that initiating the process.

[Claim 3]

　Wherein each of the plurality of terminals,
　if the wireless signal of the predetermined band by said processing state not detected successive predetermined time, based on information indicating a propagation delay between the base station and the own terminal, the transmitting the data signal to the base station as received at the reception timing of the base station in a predetermined band,
　the data signals from the timing at which the state in which a predetermined band radio signal is not detected is consecutively the predetermined time by the processing transmitting a dummy signal or a preamble until transmitting, the
　radio communication system according to claim 1 or 2, characterized in that.

[Claim 4]

　The base station, the parameters for calculating the predetermined timing and transmitted to the plurality of terminals,
　each of said plurality of terminals, and a predetermined reference timing, and parameters transmitted from the base station, on the basis in the calculated predetermined timing for starting the processing,
　the wireless communication system according to any one of claims 1 to 3, it is characterized.

[Claim 5]

　The base station, a radio communication system according to claim 4, characterized in that for transmitting the parameters determined based on a random number to said plurality of terminals.

[Claim 6]

　Each of the plurality of terminals, calculates the predetermined timing based on information shared among the plurality of terminals, calculated of claims 1 to 3, characterized in that initiating the process at the predetermined timing the wireless communication system according to any one.

[Claim 7]

　The information to be shared among multiple terminals, the wireless communication system according to claim 6, characterized in that it comprises a cell identification information of the base station.

[8.]

　The information to be shared among multiple terminals, the wireless communication system according to claim 6 or 7, characterized in that it comprises identification information of the sub-frame for the process.

[Claim 9]

　Said predetermined band processing for detecting the radio signal of any one of claims 1 to 8, which the own terminal among the predetermined band is characterized in that it is a process for detecting a radio signal in the band for transmitting a radio signal the wireless communication system according to One.

[Claim 10]

　It said predetermined band processing for detecting the wireless signal, the wireless communication system according to any one of claims 1 to 9, characterized in that a process for detecting a radio signal in the whole of the predetermined band.

[Claim 11]

　In a base station of a wireless communication system sharing a predetermined band with another wireless communication system,
　to a plurality of terminals connected to the local station, a parameter for calculating a common predetermined timing between the plurality of terminals by transmitting, to the plurality of terminals, the processing to detect a radio signal in a predetermined band starts, respectively, in the predetermined timing, the radio signal of the predetermined band by said processing state not detected in the plurality of terminals in common predetermined time sequential timing between a control unit for executing processing to start transmission of radio signals in the same band or different bands of each band included in said predetermined band, respectively,
　said plurality of a receiving unit that receives each radio signal transmitted by the terminal
　base station comprising: a.

[Claim 12]

　In the terminal of a wireless communication system for sharing a predetermined band with another wireless communication system,
　a process for detecting a radio signal of the predetermined band, with the other terminals connected to the base station to which the own terminal is connected a detection unit for starting at a common predetermined timing,
　in common for a predetermined time sequential timing between said predetermined band radio signal is state is not detected in the other terminal by the detection unit, the band included in the predetermined band a transmission section to start sending radio signals at the
　terminals, characterized in that it comprises a.

[Claim 13]

　A process by the base station of a wireless communication system for sharing a predetermined band with another wireless communication system,
　to a plurality of terminals connected to the own station, to calculate a common predetermined timing between the plurality of terminals by sending the parameters for, for the plurality of terminals, the processing to detect a radio signal in a predetermined band starts, respectively, in the predetermined timing, the radio signal of the predetermined band by said processing state not detected wherein the plurality of common predetermined time sequential timing between the terminal, to execute the processing of starting each transmit a radio signal in the same band or different bands of each band included in said predetermined band,
　said plurality of receiving each radio signal transmitted by the terminal,
　the processing method characterized by.

[Claim 14]

　A process by the terminal of a wireless communication system for sharing a predetermined band with another wireless communication system,
　a process for detecting a radio signal of the predetermined band, the other terminal connected to the base station to which the own terminal is connected common started at a predetermined timing, between
　the common predetermined time sequential timing between radio signals of the predetermined band by said processing state not detected the another terminal, band included in said predetermined band It starts transmission of radio signals, a
　processing method characterized by.