JP2012090306A - Radio base station, radio communication terminal and radio communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication device and a radio communication method capable of performing adaptive array control, with which a desired antenna composite gain can be obtained regardless of a reception state of a radio signal, while suppressing deterioration in transmission efficiency of a data symbol.SOLUTION: A radio base station 100 changes a symbol sequence configuration of a preamble symbol sequence determined by the size of frequency axis direction and time axis direction.

Description

  The present invention relates to a radio base station, a radio communication terminal, and a radio communication method that transmit and receive a radio signal including a symbol sequence having a predetermined size in a frequency axis direction and a time axis direction using an orthogonal frequency division multiplexing system.

  In recent years, for example, in a radio communication system such as WiMAX (worldwide interoperability for microwave access), an orthogonal frequency division multiplexing (OFDM) scheme is used in order to use radio resources more efficiently. In such a wireless communication system, adaptive array control using an array antenna is also introduced.

  In adaptive array control, based on “known information” included in a radio signal received from a communication destination (for example, a mobile station), an array weight used for beam forming of the radio signal transmitted to the communication destination is calculated. .

  In the OFDM scheme, a symbol string in which a plurality of symbols are arranged in the time axis direction and the frequency axis direction (subcarrier direction) is used. The symbol sequence is generally composed of preamble symbols used for symbol synchronization and array weight calculation and data symbols used for transmission of user data.

  As described above, when adaptive array control is introduced in a wireless communication system to which the OFDM scheme is applied, in order to calculate a more accurate array weight, it is used for calculating array weights in the preamble symbol portion and the data symbol portion. A method of changing known information is known (for example, Patent Document 1).

JP 2002-185375 A (page 6-7, FIG. 2)

  By the way, in the radio communication system as described above, so-called orthogonal frequency division multiple access (OFDMA) in which a predetermined number of subcarriers are allocated to each user is also realized in order to allow a plurality of users to perform communication simultaneously. .

  However, when the number of subcarriers allocated to each user is small, that is, when the frequency band allocated to each user is narrow, an antenna that can be realized by an array weight obtained using an algorithm such as the least square error method (MMSE) There is a problem that the combined gain is far from the theoretical value.

  Specifically, when the frequency band allocated to each user is narrow, the number of preamble symbols that can be arranged in the frequency axis direction is reduced, so the number of preamble symbols necessary to obtain an antenna combined gain close to the theoretical value is ensured. I can't.

  Therefore, in order to obtain an antenna combined gain close to the theoretical value, it is conceivable to arrange more preamble symbols in the time axis direction. However, if more preamble symbols are arranged in the time axis direction, the ratio of the preamble symbols included in the symbol string becomes relatively higher than the ratio of the data symbols, and the transmission efficiency of the data symbols decreases. Raise another problem.

  Therefore, the present invention has been made in view of such a situation, and adaptive array control capable of obtaining a desired antenna combined gain regardless of a reception state of a radio signal while suppressing a decrease in transmission efficiency of data symbols. It is an object of the present invention to provide a radio base station, a radio communication terminal, and a radio communication method that can execute the above.

  In order to solve the problems described above, the present invention has the following features.

  A radio base station according to the present invention is a radio base station that receives an uplink radio signal including a known signal from a radio communication terminal in a radio communication system using at least an orthogonal frequency division multiplexing system, and the known signal in the frequency axis direction Notification means for notifying the wireless communication terminal of signal configuration designation information including the bandwidth of the known signal and the period of the known signal in the time axis direction.

  A radio communication terminal according to the present invention is a radio communication terminal that transmits an uplink radio signal including a known signal to a radio base station in a radio communication system using at least an orthogonal frequency division multiplexing system, and the known signal in the frequency axis direction Receiving means for receiving, from the radio base station, signal configuration designation information including a known bandwidth and a period of the known signal in the time axis direction.

  A radio communication method according to the present invention is a radio communication method in a radio base station that receives an uplink radio signal including a known signal from a radio communication terminal in a radio communication system using at least an orthogonal frequency division multiplexing system, and the frequency axis direction And notifying the wireless communication terminal of signal configuration designation information including the bandwidth of the known signal and the period of the known signal in the time axis direction.

  A radio communication method according to the present invention is a radio communication method in a radio communication terminal that transmits an uplink radio signal including a known signal to a radio base station in a radio communication system using at least an orthogonal frequency division multiplexing method, and the frequency axis direction Receiving the signal configuration designation information including the bandwidth of the known signal and the period of the known signal in the time axis direction from the radio base station.

  According to the characteristics of the present invention, a radio base station capable of executing adaptive array control capable of obtaining a desired antenna combined gain regardless of a radio signal reception state while suppressing a decrease in transmission efficiency of data symbols, A communication terminal and a wireless communication method can be provided.

1 is an overall schematic configuration diagram of a wireless communication system according to an embodiment of the present invention. It is a functional block block diagram of the radio | wireless communication apparatus (radio base station) which concerns on embodiment of this invention. It is a functional block block diagram of the radio | wireless communication apparatus (wireless communication terminal) which concerns on embodiment of this invention. It is an operation | movement flowchart of the radio | wireless communication apparatus (radio base station) which concerns on embodiment of this invention. It is an operation | movement flowchart of the radio | wireless communication apparatus (wireless communication terminal) which concerns on embodiment of this invention. It is a figure which shows an example of the symbol row which concerns on embodiment of this invention. It is a figure which shows an example of the symbol row which concerns on embodiment of this invention. It is a figure which shows an example of the symbol row which concerns on embodiment of this invention. It is a figure which shows an example of the symbol row which concerns on embodiment of this invention.

  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 and ratios of dimensions and the like are different from actual ones.

  Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(Overall schematic configuration of wireless communication system)
FIG. 1 is an overall schematic configuration diagram of a radio communication system according to the present embodiment. As shown in FIG. 1, the radio communication system according to this embodiment includes a radio base station 100 and a radio communication terminal 200. The numbers of radio base stations and radio communication terminals are not limited to the numbers shown in FIG.

  In the radio base station 100 and the radio communication terminal 200, an orthogonal frequency division multiplexing (OFDM) scheme is used. Specifically, the wireless base station 100 and the wireless communication terminal 200 are wireless communication apparatuses compliant with WiMAX (worldwide interoperability for microwave access), and a so-called orthogonal frequency division multiple access in which a predetermined number of subcarriers are allocated to each user. (OFDMA) is used.

Also, the radio base station 100 performs adaptive array control of the downlink radio signal RS _DOWN transmitted to the radio communication terminal 200 (communication destination) based on the symbol sequence included in the uplink radio signal RS _UP received from the radio communication terminal 200. Execute.

  In this embodiment, the wireless communication terminal 200 is a card-type wireless communication terminal, and is attached to a notebook personal computer, a PDA (not shown), or the like.

(Function block configuration)
Next, configurations of the radio base station 100 and the radio communication terminal 200 will be described. Hereinafter, portions related to the present invention will be mainly described. Therefore, it should be noted that the radio base station 100 and the radio communication terminal 200 may include a logic block (power supply unit or the like) that is not shown in the figure or that is not described here, which is essential for realizing the function as the device. .

(1) Radio base station 100
FIG. 2 is a functional block configuration diagram of the radio base station 100. As shown in FIG. 2, the radio base station 100 includes a radio communication unit 101, an array control unit 103, a radio signal processing unit 105, a reception state determination unit 107, a symbol sequence configuration change unit 109, a symbol sequence configuration notification unit 111, and a base. A band processing unit 113 is provided.

The wireless communication unit 101 transmits and receives a wireless signal according to the OFDM method. Here, FIG. 6 shows an example of a symbol string included in the uplink radio signal RS _UP to the wireless communication unit 101 receives from the wireless communication terminal 200.

As shown in FIG. 6, the symbol sequence S has a predetermined size in the frequency axis direction _DF and the time axis direction _DT . The symbol sequence S is composed of a preamble symbol P and a data symbol D. Data symbol D includes a predetermined number of pilot symbols PL.

The frequency axis direction _DF is defined by the number of subcarriers, that is, the bandwidth. In the present embodiment, 9 carriers (in the figure, one row is displayed as one carrier) are defined as one unit (1 bin). The time axis direction D _T is defined by the number of OFDMA symbols.

In the present embodiment, the data symbol D is the frequency axis direction _{D F} to 18 carriers, i.e., configured 2Bin, and the time axis direction _{D T} to 3 symbols as a basic size. A plurality of data symbols D of the basic size can be arranged along the frequency axis direction _DF .

Moreover, the symbol string S, the preamble symbol P is comprised of the frequency axis direction _{D F} to 18 carriers, i.e., 2Bin, and 2 symbols (2 × 2 configuration) in the time axis direction _{D T} as the basic size. In the present embodiment, the symbol string configuration is identified based on the configuration of the preamble symbol P. That is, the symbol string S is expressed as a 2 × 2 configuration. The preamble symbol P is used for array weight calculation.

The array control unit 103 performs adaptive array control of the downlink radio signal RS _DOWN transmitted to the radio communication terminal 200 based on the symbol sequence S included in the uplink radio signal RS _UP received from the radio communication terminal 200.

Specifically, the array control unit 103 calculates an array weight applied to the downlink radio signal RS _DOWN based on the preamble symbol P (see FIG. 6). Furthermore, the array control unit 103 controls the beam pattern of the downlink radio signal RS _DOWN transmitted by the radio communication unit 101 based on the calculated array weight.

The radio signal processing unit 105 executes processing related to the downlink radio signal RS _DOWN transmitted by the radio communication unit 101 and the uplink radio signal RS _UP received by the radio communication unit 101. In particular, in the present embodiment, the radio signal processing unit 105 can change the symbol sequence configuration of the symbol sequence S included in the downlink radio signal RS _DOWN .

The reception state determination unit 107 determines the reception state of the uplink radio signal RS _UP received by the wireless communication unit 101. Specifically, the reception state determination unit 107 estimates the signal-to-noise ratio (reception SNR) of the uplink radio signal RS _UP . Specifically, the reception state determining unit 107, based on the preamble symbol P included in the uplink radio signal RS _UP, calculates a correlation between the preamble symbol P and the data symbol D, the uplink radio signal RS UP _{(subcarriers)} The received SNR is estimated. In the radio communication system according to the present embodiment, the transmission power, phase, time (transmission cycle), and the like of the uplink radio signal RS _UP are adjusted so that the reception SNR is maximized. That is, in the radio communication system according to the present embodiment, the target SNR is set with the received SNR required as a control evaluation value according to the modulation scheme used, and the uplink radio signal RS is maintained so as to maintain the target SNR. _UP control is executed.

  The symbol string configuration changing unit 109 changes the symbol string configuration of the symbol string S based on the reception state determined by the reception state determining unit 107. In this embodiment, in addition to the 2 × 2 configuration shown in FIG. 6, the 4 × 2 configuration shown in FIG. 7, the 2 × 4 configuration shown in FIG. 8, and the 8 × 1 configuration shown in FIG. 9 can be used.

In this embodiment, the 4 × 2 configuration shown in FIG. 7 is referred to as a reference symbol string configuration. Further, the 2 × 2 configuration illustrated in FIG. 6 and the 2 × 4 configuration illustrated in FIG. 8 are referred to as a narrowband symbol sequence configuration in which the size in the frequency axis direction _DF is smaller than that of the reference symbol sequence configuration. Further, the 8 × 1 configuration shown in FIG. 9 is referred to as a wideband symbol sequence configuration having a larger size in the frequency axis direction _DF than the reference symbol sequence configuration.

  That is, in the present embodiment, the symbol sequence configuration changing unit 109 changes the symbol sequence configuration of the entire symbol sequence S based on the symbol sequence configuration (for example, 4 × 2 configuration) of the preamble symbol P.

Symbol string configuration changing unit 109 when the reception state of the uplink radio signal RS _UP is determined that a predetermined condition is satisfied, specifically, the received SNR measured by the reception state determination unit 107 a predetermined threshold value If the number is lower, the configuration is changed to the narrow-band symbol sequence configuration (2 × 2 configuration) instead of the reference symbol sequence configuration (4 × 2 configuration).

  In addition, the symbol sequence configuration changing unit 109 does not use the 2 × 2 configuration (first narrowband symbol sequence configuration) but the 2 × 4 when the reception SNR measured by the reception state determination unit 107 falls below a predetermined threshold. It is also possible to change the configuration (second narrowband symbol string configuration). That is, the symbol sequence configuration changing unit 109 can change the symbol sequence configuration including the same number of preamble symbols in the reference symbol sequence configuration and the narrowband symbol sequence configuration.

  In addition, when the reception SNR measured by the reception state determination unit 107 exceeds a predetermined threshold, the symbol sequence configuration changing unit 109 replaces the reference symbol sequence configuration (4 × 2 configuration) with the wideband symbol sequence configuration (8 × 1 configuration). That is, symbol sequence configuration changing section 109 can change the symbol sequence configuration including the same number of preamble symbols in the reference symbol sequence configuration and the wideband symbol sequence configuration.

Symbol sequence configuration notifying section 111 notifies radio communication terminal 200 of the symbol sequence configuration changed by symbol sequence configuration changing section 109. Specifically, symbol sequence configuration notifying section 111 transmits a symbol sequence configuration notification indicating the symbol sequence configuration changed by symbol sequence configuration changing section 109 to radio communication terminal 200. The symbol string configuration notification is included in the downlink radio signal RS _DOWN and transmitted to the radio communication terminal 200.

  The baseband processing unit 113 is connected to the wireless signal processing unit 105. The baseband processing unit 113 transmits baseband signals such as user data and control data to the radio signal processing unit 105, and demodulates the radio signals received from the radio signal processing unit 105 into baseband signals.

(2) Radio communication terminal 200
FIG. 3 is a functional block configuration diagram of the wireless communication terminal 200. As illustrated in FIG. 2, the wireless communication terminal 200 includes a wireless communication unit 201, a wireless signal processing unit 203, a symbol sequence configuration receiving unit 205, a symbol sequence configuration changing unit 207, and a baseband processing unit 209. Hereinafter, description of functional blocks that perform the same processing as that of the above-described radio base station 100 will be omitted as appropriate.

  The wireless communication unit 201 performs substantially the same processing as the wireless communication unit 101. In addition, the wireless signal processing unit 203 performs substantially the same processing as the wireless signal processing unit 105.

The symbol sequence configuration receiving unit 205 receives the symbol sequence configuration notification transmitted by the radio base station 100. Symbol string configuration receiving section 205, based on the symbol string configuration notification received, and notifies the symbol string configuration of a symbol sequence S contained in the uplink radio signal RS _UP to symbol string configuration changing unit 207.

Symbol string configuration changing unit 207, based on the notified symbol string configuration by a symbol string configuration receiving unit 205, a symbol string configuration of a symbol sequence S contained in the uplink radio signal RS _UP, specifically, 4 × 2 configuration Change to either 2 × 2 configuration, 2 × 4 configuration, or 8 × 1 configuration.

  The baseband processing unit 209 performs substantially the same processing as the baseband processing unit 113.

(Operation of wireless communication system)
Next, the operation of the above-described wireless communication system will be described. Specifically, (1) the operation in which the radio base station 100 changes the symbol sequence configuration of the symbol sequence S based on the reception state of the uplink radio signal RS _UP , and (2) the radio communication terminal 200 is the radio base station the operation will be described of setting a symbol string configuration of a symbol sequence S contained in the uplink radio signal RS _UP on the basis of the symbol string configuration notification transmitted by 100.

(1) Radio base station 100
FIG. 4 is an operation flowchart of the radio base station 100. As shown in FIG. 4, in step S10, the radio base station 100 estimates the reception SNR of the uplink radio signal RS _UP received from the radio communication terminal 200. Specifically, the radio base station 100, based on the preamble symbol P included in the uplink radio signal RS _UP, calculates a correlation between the preamble symbol P and the data symbol D, the uplink radio signal RS UP _{(sub-carrier)} Estimate the received SNR.

  In step S20, the radio base station 100 determines whether or not the estimated received SNR satisfies a predetermined condition. Specifically, the radio base station 100 determines whether the estimated received SNR is smaller than the threshold value β, greater than or equal to the threshold value α, or larger than the threshold value β and smaller than the threshold value α.

When the estimated received SNR is smaller than the threshold β (when “received SNR <β” in step S20), in step S30A, the radio base station 100 determines the symbol sequence configuration of the symbol sequence S included in the uplink radio signal RS _UP. To a 2 × 4 configuration.

If the estimated received SNR is greater than or equal to the threshold α (when “received SNR ≧ α” in step S20), in step S30B, the radio base station 100 determines the symbol sequence configuration of the symbol sequence S included in the uplink radio signal RS _UP. To 4 × 2 configuration.

When the estimated reception SNR is larger than the threshold β and smaller than the threshold α (when “β <reception SNR <α” in step S20), in step S30C, the radio base station 100 determines that the symbol included in the uplink radio signal RS _UP The symbol column configuration of the column S is changed to a 2 × 2 configuration.

  In step S40, the radio base station 100 stores the symbol string configuration changed in any one of steps S30A to S30C.

  In step S50, the radio base station 100 transmits a symbol string configuration notification indicating the changed symbol string configuration to the communication destination, that is, the radio communication terminal 200.

As described above, in the present embodiment, as the symbol column configuration, a 4 × 2 configuration (reference symbol sequence configuration) and a 2 × 2 configuration (first symbol) whose size in the frequency axis direction _DF is smaller than that of the 4 × 2 configuration. Narrowband symbol sequence configuration) and 2 × 4 configuration (second narrowband symbol sequence configuration) having a size in the time axis direction _DT larger than the 2 × 2 configuration.

The radio base station 100, specifically, the symbol string configuration changing unit 109, if the reception state determination unit 107 receives the state of the uplink radio signal RS _UP is determined not to satisfy the predetermined condition, the 4 × 2 configuration Instead, the 2 × 2 configuration is changed. Furthermore, in the 2 × 2 configuration, the symbol sequence configuration changing unit 109 also replaces the 2 × 2 configuration with the 2 × 2 configuration when it is determined that the reception state of the uplink radio signal RS _UP does not satisfy the predetermined condition. It can be changed to 4 configurations.

  In the operation flow shown in FIG. 4, the radio base station 100 is changed to either a 4 × 2 configuration, a 2 × 2 configuration, or a 2 × 4 configuration, but further an 8 × 1 configuration (see FIG. 9). You may make it change to. In this case, as a condition for changing to the 8 × 1 configuration, the radio base station 100 uses a reception SNR better than the threshold α used for whether to change to the 4 × 2 configuration.

(2) Radio communication terminal 200
FIG. 5 is an operation flowchart of the radio communication terminal 200. As shown in FIG. 5, in step S110, the radio communication terminal 200 determines whether or not a symbol sequence configuration notification has been received from the radio base station 100 in communication.

When the symbol sequence configuration notification is received (YES in step S110), in step S120, the radio communication terminal 200 determines, based on the received symbol sequence configuration notification, the symbol sequence configuration of the symbol sequence S included in the uplink radio signal RS _UP. Set.

In step S130, the radio communication terminal 200 transmits the uplink radio signal _{RS UP} including symbol string S with a symbol string configuration set in the radio base station 100.

(Action / Effect)
As described above, in this embodiment, the data symbol D is a basic size 3 symbols 18 carriers in the frequency axis direction D _F (2bin), and the time axis direction D _T. That is, the basic size of the data symbol D in the frequency axis direction _DF and the time axis direction _DT is fixed.

In this embodiment, if the received SNR of the uplink radio signal RS _UP is good (for example, if the received SNR ≧ alpha), the large size symbol string configuration of the frequency axis direction D _F of the symbol string S (e.g., 4 By changing to (× 2 configuration), it is possible to arrange more preamble symbols P necessary for obtaining an antenna combined gain close to the theoretical value by adaptive array control in the frequency axis direction _DF . For this reason, the number of preamble symbols P to be arranged in the time axis direction _DT is reduced, and the transmission efficiency of the data symbols D is improved. Furthermore, by reducing the size of the time axis direction _DT , the influence of fading due to multipath is suppressed, and a constant communication quality can be ensured even when the radio communication terminal 200 moves at high speed.

In addition, when the reception SNR of the uplink radio signal RS _UP is poor (for example, when the reception SNR <β), the symbol sequence configuration (for example, 2 × 4 configuration) is changed to a large size in the time axis direction _DT. As a result, although the transmission efficiency of the data symbol D is lowered, the preamble symbol P necessary for obtaining the antenna combined gain close to the theoretical value by adaptive array control can be arranged while avoiding the influence of frequency selective fading. it can.

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

For example, in the above-described embodiment, as the symbol string configuration, the size in the frequency axis direction _DF and the time axis direction _DT of the preamble symbol P part is changed according to the reception state of the uplink radio signal RS _UP. Of course, it is possible to change the size of the entire symbol string S in the frequency axis direction _DF and the time axis direction _DT instead of the preamble symbol P portion.

Further, in the above embodiment, as the reception state of the uplink radio signal RS _UP, but the embodiment using the received SNR, received power value of the uplink radio signal RS _UP, timing jitter, or the like may be used frequency offset amount .

  Furthermore, in the embodiment described above, the wireless communication terminal 200 is a card-type wireless communication terminal, but the wireless communication terminal 200 may be a form other than the card-type, for example, a mobile phone terminal.

In the embodiment described above, radio communication terminal 200 is configured to set the symbol sequence configuration of symbol sequence S included in uplink radio signal RS _UP based on the symbol sequence configuration notification received from radio base station 100. However, the radio communication terminal 200 estimates the state of the uplink radio signal RS _UP based on the reception state of the downlink radio signal RS _DOWN and sets the symbol string configuration of the symbol string S included in the uplink radio signal RS _UP. It is good.

  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.

DESCRIPTION OF SYMBOLS 100 ... Wireless base station, 101 ... Wireless communication part, 103 ... Array control part, 105 ... Radio signal processing part, 107 ... Reception state determination part, 109 ... Symbol row structure change part, 111 ... Symbol row structure notification part, 113 ... Baseband processing unit, 200 ... wireless communication terminal, 201 ... wireless communication unit, 203 ... wireless signal processing unit, 205 ... symbol sequence configuration receiving unit, 207 ... symbol sequence configuration changing unit, 209 ... baseband processing unit, D ... data Symbol, D _F ... frequency axis direction, D _T ... time axis direction, P ... preamble symbol, PL ... pilot symbol, RS _UP ... uplink radio signal, RS _DOWN ... downlink radio signal, S ... symbol sequence

A radio base station according to the present invention is a radio base station that receives an uplink radio signal including a known signal from a radio communication terminal in a radio communication system using at least orthogonal frequency division multiplexing, wherein the known signal is: The radio base station is a signal used for estimating the quality of radio resources in the uplink, and includes a bandwidth of the known signal in the frequency axis direction and a period of the known signal in the time axis direction Notifying means for notifying the wireless communication terminal of configuration designation information.

A radio communication terminal according to the present invention is a radio communication terminal that transmits an uplink radio signal including a known signal to a radio base station in a radio communication system using at least orthogonal frequency division multiplexing, wherein the known signal is: The radio base station is a signal used for estimating the quality of radio resources in the uplink, and includes a bandwidth of the known signal in the frequency axis direction and a period of the known signal in the time axis direction Receiving means for receiving configuration designation information from the radio base station.

A wireless communication method according to the present invention, in a wireless communication system using at least orthogonal frequency-division multiplexing, a radio communication method in a radio base station that receives the uplink radio signal from a radio communication terminal including a known signal, the The known signal is a signal used by the radio base station to estimate the quality of radio resources in the uplink, and the bandwidth of the known signal in the frequency axis direction and the period of the known signal in the time axis direction. And notifying the wireless communication terminal of signal configuration designation information including:

A wireless communication method according to the present invention, in a wireless communication system using at least orthogonal frequency-division multiplexing, a radio communication method in a radio communication terminal for transmitting a radio uplink signal to the radio base station including a known signal, the The known signal is a signal used by the radio base station to estimate the quality of radio resources in the uplink, and the bandwidth of the known signal in the frequency axis direction and the period of the known signal in the time axis direction. Receiving the signal configuration designation information including: from the radio base station.

Claims (4)

In a radio communication system using at least orthogonal frequency division multiplexing, a radio base station that receives an uplink radio signal including a known signal from a radio communication terminal,
A radio base station comprising notification means for notifying the radio communication terminal of signal configuration designation information including a bandwidth of the known signal in the frequency axis direction and a period of the known signal in the time axis direction. In a radio communication system using at least orthogonal frequency division multiplexing, a radio communication terminal that transmits an uplink radio signal including a known signal to a radio base station,
A radio communication terminal comprising receiving means for receiving, from the radio base station, signal configuration designation information including a bandwidth of the known signal in the frequency axis direction and a period of the known signal in the time axis direction. In a radio communication system using at least orthogonal frequency division multiplexing, a radio communication method in a radio base station that receives an uplink radio signal including a known signal from a radio communication terminal,
A wireless communication method comprising a step of notifying the wireless communication terminal of signal configuration designation information including a bandwidth of the known signal in a frequency axis direction and a period of the known signal in a time axis direction. In a radio communication system using at least orthogonal frequency division multiplexing, a radio communication method in a radio communication terminal for transmitting an uplink radio signal including a known signal to a radio base station,
A radio communication method comprising a step of receiving, from the radio base station, signal configuration designation information including a bandwidth of the known signal in a frequency axis direction and a period of the known signal in a time axis direction.

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