JP2008193340A - Radio base station device, radio terminal device, wireless communication system, and channel quality indicator estimation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten the CQI estimation time for frequency scheduling while reducing the power consumption in a radio terminal device. <P>SOLUTION: A reception power estimation part 106 of a base station 100 measures an interference noise power about all RB bands being candidate frequency bands in an idle period when a pilot signal is not transmitted, and a down link signal transmission part 105 transmits interference noise power information (INI) to a UE 200. An RB selection part 203 of the UE 200 selects a frequency band in which a pilot signal for up link CQI estimation should be transmitted, on the basis of the INI, and an up link signal transmission part 207 uses the selected frequency band to transmit the pilot signal. An up link CQI estimation part 103 of the base station 100 estimates a CQI of an up link necessary for RB assignment for up link signal transmission on the basis of a reception power of the pilot signal. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radio base station apparatus, a radio terminal apparatus, a radio communication system, and a channel quality indicator estimation method that perform frequency scheduling by transmitting and receiving pilot signals for radio communication channel quality estimation.

  2. Description of the Related Art In recent years, wireless cellular systems represented by mobile phones and the like have diversified service forms and are required to transmit not only audio data but also large-capacity data such as still images and moving images.

  Already, IMT-2000 cellular system services have been provided, and standardization such as 3GPP Long Term Evolution (hereinafter LTE), which requires a peak rate of 100 Mbps in downlink, has also been performed. In addition, IMT-Advanced standardization is about to start as a category aimed at further evolution. In IMT-Advanced, for the downlink, a requirement condition of about several Gbps is indicated for the 100 MHz bandwidth, and for the uplink, a requirement condition of about several hundred Mbps is indicated for the 40 MHz bandwidth. Therefore, there is a need for a breakthrough that greatly exceeds the technology of IMT-2000.

  In particular, in IMT-Advanced, effective use of radio resources is required in order to widen both uplink and downlink, and frequency response (for each subdivided frequency (RB: Resource Block) within the band) is required. Frequency resource allocation (also referred to as “frequency scheduling”) and link adaptation according to quality / CQI (Channel Quality Indicator)) are essential.

  FIG. 18 illustrates the CQI of each RB of the base station and each UE (User Equipment) connected to the base station. In the example of FIG. 18, UE1 can use RB1 with high CQI and UE2 can use high MCS (Modulation and Coding Scheme) if it transmits signals with RB2 with high CQI. Therefore, throughput can be improved.

  When performing frequency scheduling, in order for the base station to allocate RBs by frequency scheduling, it is necessary to know CQIs of all candidate RBs of all UEs connected to the base station. In the case of FDD (Frequency Division Duplex) using different frequencies for the uplink and the downlink, the frequency response is different between the uplink band and the downlink band, so each frequency response is measured. Therefore, it is necessary for both the base station and the UE to transmit a pilot signal and the like. Normally, when transmitting data, a pilot signal for synchronous detection is required. A pilot signal for synchronous detection needs to be transmitted only in a band for transmitting data, whereas a pilot signal for quality measurement necessary for frequency resource allocation is used for the entire band of candidate RBs or data transmission. It is necessary to transmit the data in a wider band than the band, regardless of the presence or absence of data.

  For this reason, in order to measure an accurate frequency response, it is best to transmit a pilot signal or the like in the entire band of the candidate RB. However, when the UE transmits a pilot signal in the entire uplink band, there is a disadvantage that battery consumption is accelerated. Furthermore, if a UE located at the cell edge transmits a pilot signal with a large power in the entire band, interference given to neighboring cells increases, and the uplink throughput of the entire system decreases. On the other hand, if transmission power is limited in order to reduce battery consumption, when a pilot signal for CQI measurement is transmitted in a wide band, the reception power density in the base station is reduced and the CQI measurement error is increased. In particular, this effect appears remarkably in the UE near the cell edge. As a result, due to the CQI measurement error, the frequency band is not properly allocated according to the CQI, and the throughput of the entire uplink in the cell is reduced. Will be invited.

  In order to solve such a problem, a method of transmitting pilot signals with all candidate RBs by limiting RBs for transmitting pilot signals, changing the limited RBs, and transmitting a plurality of times has been studied (non-contained) Patent Document 1).

In Patent Document 1, one or a plurality of past CQI measurement values and the current CQI measurement value are combined to predict how the channel quality will be at a certain time in the future, and a predicted CQI is derived. Thus, a method of improving the follow-up of time fluctuation has been studied.
NTT DoCoMo, “Channel-Dependent Packet Scheduling for Single-Carrier FDMA in Evolved UTRA Uplink,” TSG-RAN WG1 # 43 R1-051390, November 7-11,2005 JP-T-2006-505221

  However, the conventional method requires a plurality of pilot signal transmission times in order to measure CQIs of all candidate RBs, and there is a problem that the time tracking performance of CQI deteriorates. In particular, as the bandwidth for a line becomes wider, more time is required for CQI estimation, and therefore there is a possibility that channel quality cannot be tracked with time.

  Furthermore, in CQI estimation, there is a problem that it is difficult to accurately perform CQI estimation due to the influence of interference from neighboring cells. This will be described with reference to FIG. Hereinafter, a case will be considered in which uplink signals are transmitted from UE1 and UE2 located in the same central cell as the base station to the base station located in the central cell in FIG. At this time, when UEs (interferences 1 to 6) located in the surrounding six cells adjacent to the central cell transmit uplink signals to the base stations in the cells in which they are located, the signals are transmitted to the base station of the central cell. It arrives as interference.

  Under such circumstances, when UE1 and UE2 transmit pilot signals for CQI estimation, it is difficult for the base station to distinguish the received signals into pilot signals of UE1 and UE2 and interference signals of interferences 1 to 4. The CQI is estimated based on the sum of the received power of the pilot signal, the interference power due to the interference signal, and the noise power. For this reason, when UE1 and UE2 are affected by interference during data transmission, the signal-to-interference noise ratio (SINR) is low even though the received power at the base station is high. As a result, transmission characteristics are degraded. In addition, the effect of frequency scheduling becomes low, and a significant improvement in system throughput cannot be expected.

  On the contrary, the base station sets a high CQI that also considers the power of interference received at the time of receiving the pilot signal. When the base station is not affected by the interference at the time of actual data transmission, Since scheduling is performed, characteristics at the time of data signal reception deteriorate. Therefore, also in this case, a significant improvement in system throughput cannot be expected.

  The present invention has been made in view of the above points, and can reduce a power consumption in a wireless terminal device and reduce a CQI estimation time for frequency scheduling, a wireless base station device, a wireless terminal device, and a wireless communication It is an object to provide a system and a channel quality indicator estimation method.

  One aspect of the radio base station apparatus of the present invention estimates the channel quality with the radio terminal apparatus based on the reception quality of the reference signal transmitted from the radio terminal apparatus, and based on the channel quality A radio base station apparatus for controlling uplink transmission of the radio terminal apparatus, wherein received power estimation means for measuring interference noise power at the time of reception, and of the measured interference noise power, from the radio terminal apparatus Transmitting means for transmitting information on interference noise power for a frequency band which is interference noise power measured in a period before receiving the reference signal and is a candidate for transmitting the reference signal to the wireless terminal device; The structure which comprises is taken.

  According to this configuration, when there are a plurality of frequency bands that can be used by the wireless terminal device of the communication partner, the wireless terminal device does not transmit a pilot signal that is a reference signal in all candidate frequency bands, Since the pilot signal is transmitted by narrowing down to a frequency band in which the noise power is relatively small and the channel quality is estimated to be good, the power consumption of the radio terminal apparatus can be reduced, and the radio base station apparatus Since the CQI estimation can be performed by focusing on the transmitted frequency band, the CQI can be estimated efficiently, and the CQI estimation time can be shortened.

  One aspect of the wireless terminal device of the present invention is based on information on interference noise power for a candidate frequency band transmitted from a wireless base station device, and a selection unit that selects a frequency band for transmitting a reference signal. And a transmission means for transmitting the reference signal using the frequency band.

  According to this configuration, the radio terminal apparatus does not transmit a pilot signal that is a reference signal in all candidate frequency bands, but in a frequency band in which interference noise power is relatively small and channel quality is estimated to be good. Since the pilot signal is transmitted after being narrowed down, the power consumption of the wireless terminal device can be reduced, and the wireless base station device can perform the CQI estimation by narrowing down to the frequency band in which the pilot signal is transmitted. The estimation can be performed efficiently, and the CQI estimation time can be shortened.

  One aspect of the wireless communication system of the present invention estimates the channel quality with the radio terminal device based on the reception quality of a reference signal transmitted from the radio terminal device, and based on the channel quality A radio base station apparatus for controlling uplink transmission of the radio terminal apparatus, wherein the received power estimation means for measuring interference noise power at the time of reception, and the measured interference noise power from the radio terminal apparatus Transmission means for transmitting interference noise power information about a frequency band that is interference noise power measured in a period before receiving a reference signal and is a candidate for transmitting the reference signal to the wireless terminal device; A radio base station apparatus comprising: a selection means for selecting a frequency band for transmitting a reference signal based on interference noise power information for a candidate frequency band transmitted from the radio base station apparatus; A configuration that includes a wireless terminal device comprising a transmitting means for transmitting a reference signal with the selected frequency band, and the.

  One aspect of the channel quality indicator estimation method of the present invention includes a step in which a radio base station apparatus measures interference noise power at the time of reception, and a radio terminal apparatus out of the interference noise power measured by the radio base station apparatus. Transmitting interference noise power information about the frequency band that is the interference noise power measured in the period before receiving the reference signal from the frequency band that is a candidate for transmitting the reference signal to the wireless terminal device; The wireless terminal device selects a frequency band for transmitting the reference signal from the interference noise power information for the candidate frequency band, and the wireless terminal device transmits the reference signal using the selected frequency band. A step in which the radio base station apparatus measures the received power of the reference signal, and the radio base station apparatus uses the received power of the reference signal, A step of serial reference signal to estimate the channel quality indicator of the uplink transmitted, and to have.

  According to these, when there are a plurality of frequency bands that can be used by the wireless terminal device of the communication partner, the wireless terminal device does not transmit a pilot signal that is a reference signal in all candidate frequency bands, Considering the influence of adjacent cell interference in the station apparatus, the pilot signal is transmitted only in the frequency band where the interference noise power is relatively small and the channel quality is estimated to be good, so that the power consumption of the radio terminal apparatus is reduced. In addition, since the radio base station apparatus can perform CQI estimation focusing on the frequency band in which the pilot signal is transmitted, the CQI can be estimated efficiently and the CQI estimation time can be shortened.

  ADVANTAGE OF THE INVENTION According to this invention, the CQI estimation time for frequency scheduling can be shortened, reducing the power consumption in a radio | wireless terminal apparatus.

  In the present embodiment, downlink communication for performing communication from the base station to the UE (User Equipment) and uplink communication for performing communication from the UE to the base station are different from each other (downlink: fd, uplink: fu). This is performed by frequency division duplex (FDD). The base station communicates with a plurality of UEs.

  Each frequency band used in uplink communication / downlink communication is composed of a plurality of frequency bands called RB (Resource Block).

  In addition, it is assumed that each base station and another base station in an adjacent cell operate without synchronizing the uplink signal transmission timing. That is, the period during which no uplink signal is transmitted in adjacent cells (hereinafter also referred to as “idle period”) is different.

  Hereinafter, channel quality information determined based on interference noise power measured during a period in which no uplink signal is transmitted by the base station is defined as INI (Interference plus Noise power Information), and an uplink signal is transmitted. The channel quality information determined based on the received power measured during the specified period is defined and used as CQI.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
In the present embodiment, the base station measures the received power of each candidate RB during an idle period in which no uplink signal is transmitted, and notifies the UE of the received power as interference noise power information (INI). The UE selects an RB that transmits a pilot signal based on the notified INI, and transmits the pilot signal using the selected RB. The base station estimates the CQI of each RB based on the received power of the pilot signal transmitted from the UE.

  FIG. 1 is a block diagram showing a main part configuration diagram of base station 100 according to Embodiment 1 of the present invention.

  1, the base station 100 includes an uplink signal receiving unit 101, an uplink signal demodulating unit 102, an uplink CQI estimating unit 103, a downlink signal modulating unit 104, a downlink signal transmitting unit 105, a received power estimating unit 106, An uplink RB allocation unit 107 and a switch 108 are provided.

  Uplink signal receiving section 101 performs radio reception processing such as amplification processing, A / D conversion, and radio demodulation processing on the signal received by the reception antenna, and extracts a received baseband signal. Uplink signal receiving section 101 outputs a received baseband signal to uplink signal demodulating section 102 and received power estimating section 106.

  Uplink signal demodulation section 102 performs baseband demodulation processing on the received baseband signal and extracts received data.

  Received power estimation section 106 estimates the received power of each candidate RB from the received baseband signal. The reception power estimation unit 106 estimates interference noise power (IN: Interference plus Noise power) as reception power during a period when no uplink signal is transmitted, and during a period when a pilot signal is transmitted. Is estimated. The reception power estimation unit 106 sets interference noise power information (INI) from interference noise power (IN) during a period in which no uplink signal is transmitted, and interference noise power information (INI). Is output to the switch 108 as received power information. During the period in which the pilot signal is being transmitted, reception power estimation section 106 outputs the reception power of the pilot signal to switch 108 as reception power information.

  As a method for the reception power estimation unit 106 to set the interference noise power information (INI) from the interference noise power of each candidate RB, for example, the larger the interference noise power, the lower the INI, and the smaller the interference noise power, the INI. Set high.

  The switcher 108 switches the output destination of the received power information output from the received power estimation unit 106 based on the frame timing information. When the frame timing information indicates an idle period during which no uplink signal is transmitted, the switch 108 outputs interference noise power information (INI) to the downlink signal modulator 104 as received power information. On the other hand, when the frame timing information indicates that the pilot signal is being transmitted, the switch 108 outputs the received power of the pilot signal to the uplink CQI estimating unit 103 as received power information.

  Uplink CQI estimation section 103 estimates channel quality information (CQI) of each candidate RB from the received power information output from switch 108.

  Uplink RB assigning section 107 assigns RBs used when each UE transmits an uplink data signal from the uplink CQI of each UE, and sends information on the assigned RBs to the uplink CQI assignment notification signal. To the downlink signal modulation section 104.

  The downlink signal modulation section 104 performs baseband modulation processing on data to be transmitted on the downlink, generates a transmission baseband signal, and outputs the transmission baseband signal to the downlink signal transmission section 105. Also, when transmitting INI and CQI on the downlink, the downlink signal modulation unit 104 performs baseband modulation processing on each piece of information as in the case of transmission data, and generates a transmission baseband signal. It outputs to the downlink signal transmission part 105.

  The downlink signal transmission unit 105 performs radio transmission processing such as amplification processing, frequency conversion, and D / A conversion on the transmission baseband signal, and then transmits the transmission signal after the radio transmission processing from the transmission antenna.

  FIG. 2 is a block diagram showing a configuration diagram of UE 200 in Embodiment 1 of the present invention.

  In FIG. 2, the UE 200 includes a downlink signal reception unit 201, a downlink signal demodulation unit 202, an RB selection unit 203, an uplink signal modulation unit 204, a transmission RB mapping unit 205, a pilot signal generation unit 206, and uplink signal transmission. A unit 207 is provided.

  The downlink signal reception unit 201 performs radio reception processing such as amplification processing, A / D conversion, and radio demodulation processing on the signal received by the reception antenna, and extracts a reception baseband signal. The downlink signal reception unit 201 outputs the received baseband signal to the downlink signal demodulation unit 202.

  The downlink signal demodulating section 202 performs baseband demodulation processing on the received baseband signal and extracts received data. Further, when the received data includes an INI or an uplink transmission RB assignment notification signal, the downlink signal demodulating section 202 extracts these information from the received data and outputs the information to the RB selecting section 203.

  When the INI is output from the downlink signal demodulating unit 202, the RB selecting unit 203 selects one or a plurality of RBs that transmit pilot signals for estimating a propagation path from the INI and transmission data information. To do. The transmission data information will be described later. Furthermore, when an uplink transmission RB allocation notification signal is output from the downlink signal demodulation unit 202, the RB selection unit 203 includes RB allocation information included in the uplink transmission RB allocation notification signal determined by the pilot signal. Based on RB, the RB for transmitting the uplink data signal is selected. The RB selection unit 203 outputs information on the selected RB to the transmission RB mapping unit 205.

  Uplink signal modulation section 204 performs baseband modulation processing on the data to be transmitted on the uplink, generates a transmission baseband signal, and outputs the transmission baseband signal to transmission RB mapping section 205.

  Pilot signal generation section 206 generates a pilot signal to be transmitted to measure uplink CQI, and outputs the pilot signal to transmission RB mapping section 205.

  Transmission RB mapping section 205 maps the transmission baseband signal or the pilot signal for CQI estimation to the RB selected by RB selection section 203. The transmission RB mapping unit 205 outputs the mapped baseband signal to the uplink signal transmission unit 207.

  Uplink signal transmission section 207 performs wireless transmission processing such as amplification processing, frequency conversion, and D / A conversion on the transmission baseband signal mapped to the RB to be transmitted, and then transmits the transmission RF ( Radio Frequency) modulated signal is transmitted from the transmitting antenna.

  Hereinafter, operations of the base station 100 and the UE 200 configured as described above will be described.

  FIG. 3 is a diagram illustrating an example of a signal flow of uplink (communication from the UE to the base station) / downlink (communication from the base station to the UE) communication in the present embodiment.

  First, the operation of the base station 100 will be described.

  In FIG. 3, a period (A) is an idle period in which uplink communication is not performed. In period (A), received power estimation section 106 in base station 100 measures the received power of each RB. The period (A) is an idle period in which no uplink signal is transmitted, and, as described above, since the idle period is different from the base station of the adjacent cell, the received power measured by the received power estimation unit 106 Corresponds to the interference noise power. Received power estimation section 106 sets INI from the interference noise power of each RB, and outputs it to switch 108. As an example of an INI setting method, the larger the interference noise power, the lower the INI is set, and the smaller the interference noise power is, the higher the INI is set.

  In the period (A), since the frame timing information indicates an idle period, the switch 108 outputs INI to the downlink signal modulation unit 104.

  In the period (B), the downlink signal modulation section 104 performs baseband modulation processing on the INI of each RB output from the switch 108 and outputs the result to the downlink signal transmission section 105. The downlink signal transmission unit 105 transmits a transmission RF modulation signal including the INI of each RB to the UE.

  Next, the operation of UE 200 will be described.

  The transmission RF modulation signal transmitted from the downlink signal transmission unit 105 of the base station 100 is received by a plurality of UEs. Below, although operation | movement of UE200 which is one of them is demonstrated, the same process is performed also in other UE. The downlink signal reception unit 201 receives a transmission RF modulation signal including the INI of each RB, obtains a reception baseband signal, and outputs the received baseband signal to the downlink signal demodulation unit 202. Downlink signal demodulation section 202 performs demodulation processing on the received baseband signal and extracts the INI of each RB. The downlink signal demodulation section 202 outputs the INI of each RB to the RB selection section 203.

  RB selection section 203 selects an RB for transmitting a pilot signal from INI and transmission data information. Below, the case where the desired QoS of transmission data is used is demonstrated as an example of transmission data information.

  FIG. 4 is a diagram showing the relationship between the desired QoS level of transmission data and INI. Data with a high QoS represents data with the smallest allowable error, and data with a low QoS represents data with the largest allowable error.

  The RB selection unit 203 refers to the QoS level of the transmission data. When the QoS level is high, the RB selection unit 203 receives an INI as an RB for transmitting a pilot signal so that an RB having a high channel quality can be allocated from the base station 100 during data transmission. One or more RBs having high interference noise, that is, low interference noise power are selected. On the other hand, when the QoS level of the transmission data is low, some transmission errors can be tolerated, and one or more are selected including RBs having low INI, that is, high interference noise power, as RBs for transmitting pilot signals. In this way, when the QoS level of the transmission data is low, the UE 200 transmits a pilot signal only by the RB limited to the RB having a low INI and a high interference noise power. The pilot signal can be transmitted using the RB having a high interference noise power and a high interference noise. Thereby, the frequency utilization efficiency as the whole system can be improved.

  RB selection section 203 outputs the selected RB information (pilot signal transmission RB information) to transmission RB mapping section 205.

  Pilot signal generation section 206 generates a pilot signal for performing uplink CQI estimation. Based on the pilot signal transmission RB information output from RB selection section 203, transmission RB mapping section 205 maps the pilot signal to one or more selected RBs. Uplink signal transmission section 207 transmits a pilot signal for uplink CQI estimation from the transmission antenna in period (C) in FIG.

  From here, the operation of the base station 100 will be described.

  The pilot signal transmitted from UE 200 is received by the receiving antenna of base station 100. In addition, pilot signals transmitted simultaneously from UEs other than UE 200 are also received in the same cell. The uplink signal receiving unit 101 converts the received signal into a baseband signal.

  Received power estimation section 106 estimates the received power of each RB and outputs it to switch 108. In the period (C), since the frame timing information indicates that the pilot signal is being transmitted, the switch 108 outputs the received power to the uplink CQI estimation unit 103.

  Uplink CQI estimation section 103 estimates the uplink CQI of each UE from the pilot signal of each UE. Here, as an estimation method of the uplink CQI, a method of measuring received power of a pilot signal, a signal to interference power ratio (SNR) or a signal to interference noise power ratio (SINR) of a pilot signal Any method such as a method of measuring the interference noise ratio) or a method of estimating the amplitude / phase fluctuation of the propagation path by performing equalization processing on the pilot signal can be used.

  The uplink CQI estimation unit 103 outputs the estimated uplink CQI of each UE to the uplink RB allocation unit 107. The uplink RB allocation unit 107 performs frequency scheduling based on the uplink CQI of each UE, and allocates an RB for each UE to transmit an uplink signal.

  In the period (D), the base station 100 transmits a downlink signal including an RB assignment notification signal in which each UE specifies an RB for transmitting the uplink signal.

  From here, operation | movement of UE200 is demonstrated.

  Each UE receives a downlink signal including an RB allocation notification signal, and reads an RB used for uplink signal transmission described in the RB allocation notification signal.

  In the period (E), the UE 200 transmits an uplink signal using the RB allocated from the base station 100.

  As described above, according to the present embodiment, UE 200 selects an RB that transmits a pilot signal based on interference noise power for all RB bands, which are candidate frequency bands measured by base station 100, and a channel. Since RBs with good quality are narrowed down and pilot signals can be transmitted only with the narrowed RBs, UE 200 does not need to transmit pilot signals with all uplink candidate RBs, and power consumption for transmitting pilot signals Can be reduced. In addition, the base station 100 can estimate the uplink CQI necessary for performing RB allocation for uplink signal transmission by only transmitting the pilot signal from the UE 200 once, so the CQI estimation is performed. It can be done in a short time.

  In addition, although the base station 100 in this Embodiment demonstrated the case where INI was set based on the magnitude | size of interference noise power, it is not restricted to this, For example, the base station 100 has interference noise power and INI. A table indicating the correspondence may be owned in advance, and the INI of each RB may be set based on the table.

  In the above description, the RB selection unit 203 has been described as using the QoS based on the allowable error of the transmission data as the transmission data information. However, other information may be used as the transmission data information. For example, when transmitting retransmission data using information indicating whether transmission data is retransmission data, by selecting a RB having a high INI and a low interference noise power, a pilot signal is transmitted, thereby transmitting retransmission data. Certainty can be improved.

  As another example, the distance between the UE and the base station can be used as transmission data information. As the distance between the UE and the base station is closer, the signal from the UE is expected to be received at a higher received power at the base station. Therefore, pilots using higher INIs, that is, RBs with lower interference noise power, are used. Send a signal.

  By doing so, an RB for transmitting an uplink data signal is allocated from among RBs having a high INI that transmits a pilot signal and a small interference noise power by the base station. Uplink data signals can be transmitted using Modulation and Coding Scheme. As another selection method in this case, a pilot signal may be transmitted with an RB having a higher INI, that is, a smaller interference noise power, as the UE is further away from the base station. By transmitting using RB with low interference noise power, communication can be performed correctly even when the distance from the base station is low and the reception power at the base station is low.

  As another example, the moving speed of the UE 200 can be used as transmission data information. At this time, a UE with a faster moving speed and a larger change in channel state transmits a pilot signal with an RB having a lower INI, that is, with a larger interference noise power, and the moving speed is slower and the channel state does not change much. When the pilot signal is transmitted with an RB having a high INI, that is, with a small interference noise power, a UE having a low moving speed and a small change in channel state transmits data with an RB having a poor channel quality. The situation of continuing to do so can be avoided.

  Further, as another example, the amount of transmission data is used as transmission data information, and a UE with a smaller amount of data to be transmitted transmits a pilot signal with an RB having a higher INI, that is, with less interference noise power. RBs with good channel quality may be assigned. In this way, transmission data can be transmitted in a short time using a high MCS, and the RB occupation time with good channel quality can be reduced.

  As another example, when the immediacy of transmission data is used as QoS and the immediacy of data to be transmitted is high, a pilot signal is transmitted with an RB with a high INI, that is, with a small interference noise power, and the channel quality is A good RB may be assigned.

  In the present embodiment, the case has been described in which RB selection section 203 selects an RB that transmits a pilot signal using transmission data information. However, RB selection section 203 selects an RB that transmits a pilot without using transmission data information. You may make it do. In this case, the RB selection unit 203 may not select an RB having a low INI and a high interference noise power, and may select an RB that transmits a pilot signal from RBs having a high INI and a low interference noise power. Good. By doing so, the UE can avoid the RB with poor channel quality, which is expected to be difficult to correctly estimate CQI with much interference at the base station, and can transmit the pilot signal in advance. It can be avoided that the RB assigned by the base station includes an RB with poor channel quality.

  Note that the number of RBs for transmitting pilot signals may be increased or decreased according to INI. In this case, when transmitting a pilot signal using an RB having a high INI and a low interference noise power, the RB selection unit 203 reduces the number of RBs to be selected, selects an RB having a low INI and a high interference noise power. When the pilot signal is transmitted by using it, a process of increasing the number of RBs to be selected is performed. In this way, when pilot signals are transmitted using RBs with low INI and poor channel quality, the number of RBs used increases, so the probability that RBs with good CQI can be obtained by frequency diversity. Will improve.

  In the present embodiment, UE 200 is configured to transmit a pilot signal in order to estimate uplink CQI. However, UE 200 may be transmitted including transmission data information in the pilot signal. In this case, the uplink transmission RB allocation unit 107 of the base station 100 can perform uplink transmission RB allocation using transmission data information in addition to the uplink CQI of each RB estimated by the pilot signal, which is more effective. Transmission RB allocation can be performed.

(Embodiment 2)
In the present embodiment, the base station assigns the interference noise power measured by the base station to the transmission power level of a signal in a part of the frequency band of the downlink frequency band, and notifies the UE.

  FIG. 5 is a block diagram showing a main configuration of the base station according to Embodiment 2 of the present invention. In the description of the present embodiment, the same components as those in FIG.

  The difference from Embodiment 1 is that base station 300 of this embodiment includes downlink signal transmission section 301 instead of downlink signal transmission section 105.

  The downlink signal transmission unit 301 transmits the transmission power of a part of the RBs in the downlink frequency band with power that is inversely proportional to the interference noise power. Hereinafter, the frame whose transmission power is changed is referred to as an “INI notification frame”. Note that it is determined in advance which part of the downlink frequency band the RB that makes the transmission power inversely proportional to the interference noise power corresponds to. At this time, downlink signal transmission section 301 transmits the transmission power of the pilot signal for downlink channel estimation without changing it.

  FIG.6 is a block diagram showing a main configuration of the UE according to Embodiment 2 of the present invention. In the description of the present embodiment, the same components as those in FIG.

  The difference from Embodiment 1 is that UE 400 of this embodiment includes downlink signal reception section 401 and further includes INI estimation section 402 instead of downlink signal reception section 201.

  The downlink signal reception unit 401 extracts a baseband signal from the downlink signal transmitted from the base station 100 and outputs the received power of the INI notification frame after channel equalization to the INI estimation unit 402.

  The INI estimation unit 402 estimates the INI from the received power of the INI notification frame, and outputs the estimated INI to the RB selection unit 203. As described above, the base station 300 transmits the INI notification frame with power that is inversely proportional to the interference noise power. In the RB where the power of the INI notification frame is low, the interference noise power is large, so the INI estimation unit 402 sets INI low. On the other hand, in the RB in which the power of the INI notification frame is high, the interference noise power is small, so the reception power estimation unit 106 sets INI high. The INI estimation unit 402 outputs the set INI to the RB selection unit 203. RB selection section 203 selects an RB for transmitting a pilot signal from INI and transmission data information, as in the first embodiment. The RB selection unit 203 transmits information on the selected RB to the transmission RB mapping unit 205.

  Hereinafter, operations of the base station 300 and the UE 400 configured as described above will be described focusing on transmission / reception of INI notification frames.

  Similar to Embodiment 1, received power estimation section 106 in base station 100 measures the received power of each RB. In an idle period in which no uplink signal is transmitted, reception power estimation section 106 sets INI from the interference noise power of each RB and outputs it to switch 108. As an example of the setting method at this time, INI is set lower as the interference noise power is larger, and INI is set higher as the interference noise power is smaller.

  The switch 108 outputs INI to the downlink signal transmission unit 301 when the frame timing information indicates an idle period.

  Based on the INI, the downlink signal transmission unit 301 makes the transmission power of some RBs in the downlink frequency band inversely proportional to the interference noise power, and sends an INI notification frame whose transmission power is inversely proportional to the interference noise power to the UE. To send.

  The transmission RF modulation signal transmitted from the downlink signal transmission unit 301 of the base station 300 is received by a plurality of UEs. Below, although operation | movement of UE400 which is one of them is demonstrated, the same process is performed also about other UE.

  FIG. 7 is a diagram for explaining an uplink INI notification frame. In FIG. 7, the horizontal axis represents time, and the vertical axis represents the downlink frequency. The downlink signal transmission unit 301 transmits the transmission power of a part of the RBs of the downlink frequency with power inversely proportional to the interference noise power. In the example shown in FIG. 7, the transmission power of the RBs in the downlink frequencies fd1 to fd2 (bandwidth Δf) is inversely proportional to the interference noise power of the RBs in the uplink frequencies fu1 to fu2 (bandwidth Δf). Is done.

  FIG. 8 is a diagram illustrating the relationship between the transmission power of the INI notification frame and the downlink frequency. As shown in FIG. 8, the transmission power of RBs in the downlink frequencies fd1 to fd2 (bandwidth Δf) fluctuates because they are set in inverse proportion to the interference noise power of the uplink frequencies fu1 to fu2. In the frequency band other than the downlink frequencies fd1 to fd2, the transmission power of the downlink signal is constant without being changed.

  When the INI notification frame having power inversely proportional to the interference noise power of the RB of the uplink signal is transmitted, the downlink signal reception unit 401 of the UE 400 outputs the reception power of the INI notification frame to the INI estimation unit 402.

  The INI estimation unit 402 estimates the INI from the received power of the INI notification frame, and outputs the estimated INI to the RB selection unit 203.

  As described above, in this embodiment, based on the interference noise power, the transmission power of a signal in a part of the downlink frequency band is changed, and the INI notification frame whose transmission power is changed is used as the downlink signal. By transmitting, INI information can be included in the power level of the downlink transmission signal. As a result, the UE 400 can estimate the INI by receiving the INI notification frame, and can limit the RB that transmits the pilot signal.

  In this embodiment, the transmission power level of the INI notification frame is set to a level that is inversely proportional to the interference noise power. However, the transmission power level of the INI notification frame is set to a level that is directly proportional to the interference noise power. You may make it set. By doing in this way, even when the channel quality between the base station 300 and the UE 400 is poor, it is possible to reliably notify RB information with a high interference noise power, that is, with a low INI.

  In the present embodiment, some information of the downlink communication signal may be included in the INI notification frame. In this way, it is not necessary to prepare a downlink frequency band only for notifying the INI, so that the frequency band utilization efficiency can be improved.

(Embodiment 3)
In the present embodiment, the base station performs INI notification in the same frequency band as that in which uplink communication is performed.

  FIG. 9 is a block diagram showing a main configuration of the base station according to Embodiment 3 of the present invention. In the description of the present embodiment, the same components as those in FIG.

  The difference from Embodiment 1 is that base station 500 of this embodiment further includes INI notification signal modulation section 501, INI notification signal transmission section 502, and transmission / reception switch 503.

  The INI notification signal modulation unit 501 modulates the INI estimated by the received power estimation unit 106 into data as a baseband signal, and outputs it to the INI notification signal transmission unit 502.

  The INI notification signal transmission unit 502 performs wireless transmission processing such as amplification processing and frequency conversion on the baseband signal output from the INI notification signal modulation unit 501, and then transmits the uplink signal via the transmission / reception switch 503. An INI notification signal is transmitted from the antenna in the same frequency band as the frequency band to be used.

  The transmission / reception switcher 503 performs switching control between signal reception and signal transmission. The transmission / reception switcher 503 switches transmission / reception between receiving an uplink signal and a pilot signal and transmitting an INI notification signal.

  FIG. 10 is a block diagram showing a main configuration of the UE according to Embodiment 3 of the present invention. In the description of the present embodiment, the same components as those in FIG.

  The difference from Embodiment 1 is that UE 600 of this embodiment further includes transmission / reception switcher 601, INI notification signal receiver 602, and INI notification signal demodulator 603.

  The transmission / reception switcher 601 switches transmission / reception between receiving an uplink CQI notification signal and transmitting an uplink signal or a pilot signal.

  The INI notification signal reception unit 602 performs reception signal processing of the INI notification signal received by the antenna and extracts a baseband signal.

  The INI notification signal demodulation unit 603 extracts the uplink INI from the baseband signal and outputs the uplink INI to the RB selection unit 203.

  Hereinafter, operations of base station 500 and UE 600 configured as described above will be described.

  FIG. 11 is a diagram illustrating an example of a signal flow of uplink / downlink communication according to the present embodiment.

  In FIG. 11, a period (A) is an idle period in which uplink communication is not performed. In period (A), reception power estimation section 106 in base station 500 estimates the interference noise power of each RB, as in Embodiment 1, and uses the estimated interference noise power of each RB to determine the INI of each RB. Set.

  In the period (B), the INI notification signal modulation unit 501 performs baseband modulation processing on the INI of each RB, and the INI notification signal transmission unit 502 transmits an INI notification signal including information on the INI of each RB to the UE. Send to. At this time, the frequency band for transmitting the INI notification signal uses the same frequency band as the frequency band for transmitting the pilot signal and the uplink signal.

  The INI notification signal transmitted from the INI notification signal transmission unit 502 of the base station 500 is received by a plurality of UEs. Below, although operation | movement of UE600 which is one of them is demonstrated, the same process is performed also about other UE. The INI notification signal reception unit 602 receives the INI notification signal including the INI of each RB, obtains a reception baseband signal, and outputs the received baseband signal to the INI notification signal demodulation unit 603. The INI notification signal demodulation unit 603 performs demodulation processing on the received baseband signal and extracts the INI of each RB. The INI notification signal demodulation unit 603 outputs the INI of each RB to the RB selection unit 203.

  RB selection section 203 selects an RB for transmitting a pilot signal from INI and transmission data information. At this time, as an example of the transmission data information, the same transmission data information used in Embodiment 1 can be used. RB selection section 203 outputs the selected RB information (pilot signal transmission RB information) to transmission RB mapping section 205.

  Thereafter, similarly to Embodiment 1, UE 600 selects an RB for transmitting a pilot signal, transmits a pilot signal using the selected RB (period (C)), and base station 500 transmits a pilot for each UE. Estimate the uplink CQI of each UE from the signal, perform frequency scheduling based on the estimated uplink CQI of each UE, perform RB allocation for each UE to transmit an uplink signal, and send an RB allocation notification signal The UE 600 transmits the uplink signal using the RB allocated from the base station 500 (period (E)).

  As described above, according to the present embodiment, base station 500 transmits interference noise power information to each UE using the same frequency band as that used for uplink communication. Therefore, the UE can estimate the status of the communication path of each RB, and can select the RB that transmits the pilot signal by combining the status of the communication path of each RB and the interference noise power information included in the INI notification signal. .

  In the above description, base station 500 has described the case of notifying UE of an INI notification signal obtained by modulating INI into a baseband signal. However, as in the second embodiment, base station 500 determines the transmission power level of INI notification signal. You may make it modulate and notify based on interference noise electric power.

  In this way, the UE that has received the INI notification signal can estimate the RB CQI by observing the reception power of the INI notification signal of each RB. By limiting the number of RBs for transmitting pilot signals using this estimated value, it is possible to perform accurate CQI estimation with a small number of pilot signal transmissions. Also, by transmitting the INI notification signal at a transmission power level that is directly proportional to the interference noise power level, even when the radio channel environment between the base station and the UE is poor, the interference noise power level is high, that is, the INI is low. The RB information can be notified to the UE.

  In the above description, a case has been described in which the downlink signal uses a frequency band different from the frequency band used by the uplink signal, the pilot signal, and the INI notification signal. However, in each UE, the downlink signal, the uplink signal, The same effect can be obtained also in the case of a time division duplex (TDD) system in which the link signal, the pilot signal, and the INI notification signal use the same frequency band.

(Embodiment 4)
FIG. 12 is a block diagram showing a main configuration of the UE according to Embodiment 4 of the present invention. In the description of the present embodiment, the same components as those in FIG.

  The difference from Embodiment 1 is that UE 700 of this embodiment further includes an uplink signal transmission section 701 and two transmission systems. Note that the number of transmission systems is not limited to two, and three or more transmission systems may be provided. In this case, a configuration in which an uplink signal transmission unit is added according to the number of transmission systems may be adopted. Further, the reception system of UE 700 is not limited to one and may be two or more.

  The configuration of the main part of the base station according to Embodiment 4 is the same as in FIG. 1 employs a configuration including one transmission / reception system, but the present invention can also be applied to a case where there are two or more transmission / reception systems.

  The uplink signal transmission unit 701 transmits a pilot signal or an uplink data signal in a frequency band different from that of the uplink signal transmission unit 207. Therefore, when there are a plurality of RBs selected by the RB selection unit 203 and they are not continuous on the frequency axis, the uplink signal transmission unit 207 and the uplink signal transmission unit 701 use different frequency bands to generate pilot signals. Respectively. Thus, the pilot signal transmitted from UE 700 becomes a single carrier signal using consecutive RBs transmitted from a single antenna for uplink signal transmission sections 207 and 701.

  On the other hand, in UE 100 including only uplink signal transmission section 207, RB selection section 203 selects RBs that are not continuous on the frequency axis, and a single antenna transmits a pilot signal mapped to each RB. In this case, it is conceivable that the pilot signal transmitted from the UE 100 is transmitted as a multicarrier signal. In this multicarrier signal, a power peak occurs on the time axis. Therefore, it is necessary to increase the margin of the power amplifier, and the transmission power cannot be increased, or the same transmission power as in single carrier transmission. In order to obtain the above, there arises a problem that a high-performance power amplifier is required.

  On the other hand, UE 700 according to the present embodiment includes a plurality of transmission antennas, and uses different RBs from the respective transmission antennas when RBs selected by RB selection unit 203 are not continuous on the frequency axis. By transmitting the pilot signal, the pilot signal transmitted from the UE 700 becomes a single carrier signal using continuous RBs transmitted from a single antenna via the uplink signal transmission units 207 and 701. The occurrence of power peaks can be avoided.

  Hereinafter, operations of the base station 100 and the UE 700 configured as described above will be described with reference to FIG. 3 again.

  First, the operation of the base station 100 will be described.

  In period (A), reception power estimation section 106 in base station 100 measures the interference noise power of each RB as in Embodiment 1, and outputs the measured interference noise power (INI) to switch 108. To do.

  In the period (A), since the frame timing information indicates an idle period, the switch 108 outputs INI to the downlink signal modulation unit 104.

  Similarly to the first embodiment, in the period (B), the downlink signal modulation section 104 performs baseband modulation processing on the INI of each RB output from the switch 108 to transmit downlink signals. Output to the unit 105. The downlink signal transmission unit 105 transmits a transmission RF modulation signal including the INI of each RB to each UE.

  Next, the operation of UE 700 will be described.

  The transmission RF modulation signal transmitted from the downlink signal transmission unit 105 of the base station 100 is received by a plurality of UEs. Below, although operation | movement of UE700 which is one of them is demonstrated, the same process is performed also about other UE. The downlink signal reception unit 201 receives an RF signal including the INI of each RB, obtains a received baseband signal, and outputs the received baseband signal to the downlink signal demodulation unit 202. Downlink signal demodulation section 202 performs demodulation processing on the received baseband signal and extracts the INI of each RB. The downlink signal demodulation section 202 outputs the INI of each RB to the RB selection section 203.

  The RB selection unit 203 selects an RB for transmitting a pilot signal from the INI and transmission data information for each of the two transmission antennas of the uplink signal transmission units 207 and 701. As the transmission data information, the desired QoS of the transmission data can be used as in the first embodiment.

  RB selection section 203 outputs RB information (pilot signal transmission RB information) of each selected transmission antenna to transmission RB mapping section 205.

  UE 700 transmits a pilot signal for uplink CQI estimation in period (C) in FIG. Pilot signal generation section 206 generates a pilot signal for performing uplink CQI estimation. Based on the pilot signal transmission RB information output from RB selection section 203, transmission RB mapping section 205 maps the pilot signal to one or a plurality of corresponding RBs. Uplink signal transmission sections 207 and 701 transmit pilot signals using different RBs from the two transmission antennas.

  From here, the operation of the base station 100 will be described.

  The pilot signal transmitted from UE 700 is received by the receiving antenna of base station 100. At this time, pilot signals simultaneously transmitted from UEs other than UE 700 are also received. The uplink signal receiving unit 101 converts the received signal into a baseband signal.

  Received power estimation section 106 estimates the received power of each RB and outputs it to switch 108. In the period (C), since the frame timing information indicates that the pilot signal is being transmitted, the switch 108 outputs the received power to the uplink CQI estimation unit 103.

  Similarly to Embodiment 1, uplink CQI estimation section 103 estimates the uplink CQI of each UE from the pilot signal of each UE. The uplink CQI estimation unit 103 outputs the estimated uplink CQI of each UE to the uplink RB allocation unit 107. The uplink RB allocation unit 107 performs frequency scheduling based on the uplink CQI of each UE, and allocates an RB for each UE to transmit an uplink signal.

  In the period (D), the base station 100 transmits a downlink signal including an “RB allocation notification signal” that specifies an RB to which each UE transmits an uplink signal.

  From here, the operation of the UE will be described.

  Each UE receives a downlink signal including an RB allocation notification signal, and reads an RB used for uplink signal transmission described in the RB allocation notification signal.

  In the period (E), the UE 700 transmits an uplink signal using the RB allocated from the base station 100. At this time, among the two transmission antennas of the uplink signal transmission units 207 and 701, the uplink signal is transmitted using the same RB from the transmission antenna that has transmitted the pilot signal using the RB allocated in the period (C). Sent. At this time, no signal is transmitted from the other transmitting antenna.

  As described above, according to the present embodiment, a pilot signal is transmitted from a plurality of transmission antennas using different RBs. Therefore, a plurality of RBs that are not continuous on the frequency axis are selected by the RB selection unit 203. When selected, the pilot signal transmitted from the UE 700 can be regarded as a single carrier signal using continuous RBs when it is regarded as transmitted from a single antenna. By avoiding this, the peak power to the average power can be reduced, and the ACLR (Adjacent Channel Leakage power Ratio) can be reduced.

  In the above description, in the period (E), the uplink signal is transmitted using the same RB from the transmission antenna that transmits the pilot signal using the RB allocated in the period (C), and the other Although the configuration is such that no signal is transmitted from the transmission antenna, an uplink signal may also be transmitted from the other transmission antenna using the same RB. In this case, the other transmission antenna transmits a signal obtained by cyclically shifting the uplink signal. By doing in this way, frequency diversity gain can be obtained by the effect of cyclic shift diversity (CSD) at the time of reception at base station 100.

  In the present embodiment, the CQI estimation method in the FDD system using different frequencies in the uplink frequency band and the downlink frequency band has been described according to the example of FIG. 3, but described in FIG. 11 of the third embodiment. As described above, the above-described CQI estimation method can be similarly applied to a method of notifying an INI notification signal using an uplink frequency band and a TDD system.

  In the present embodiment, the pilot signal is transmitted using different RBs from a plurality of transmission antennas, but the pilot signal may be transmitted using the same RB. In this case, it is possible to estimate the CQI including the effect of CSD by applying a cyclic shift to the pilot signal transmitted from one transmission antenna.

(Embodiment 5)
In the fifth embodiment, the base station includes a transmitting antenna and a receiving antenna capable of directivity control, and measures interference noise power for each specific direction during an idle period in which no pilot signal is transmitted, and for each direction. By notifying the UE of the INI estimated based on the measured interference noise power, the CQI estimation accuracy in an environment where there is adjacent cell interference is improved and the pilot signal transmission efficiency of the UE is improved.

  FIG. 13 is a diagram showing a state of base station and adjacent cell interference according to the present embodiment. In the following, as shown in FIG. 13, a case where a cell in which base station 800 exists is adjacent to six cells, and interference sources (interference 1 to interference 6) exist in each cell will be described.

  FIG. 14 is a block diagram showing a main configuration of the base station according to the present embodiment. In the description of the present embodiment, the same components as those in FIG.

  The difference from Embodiment 1 is that base station 800 of this embodiment includes switch 802 instead of switch 108, and further includes reception directivity control section 801 and transmission directivity control section 803. There is.

  Reception directivity control section 801 controls reception directivity of base station 800. As a control method at this time, a directivity is controlled by multiplying a reception signal from a plurality of reception antennas by weights, or a plurality of reception antennas having a single directivity are provided and controlled by switching them. A method or the like can be used. Reception directivity control section 801 outputs the received signal and information on the reception directivity at that time (hereinafter referred to as “directivity information”) to reception power estimation section 106.

  The reception power estimation unit 106 receives a reception signal and directivity information from the reception directivity control unit 801 and estimates reception power for each direction. As in the first embodiment, the received power in the idle period in which no pilot signal is transmitted corresponds to the interference noise power in the reception direction. Received power estimation section 106 outputs received power and directivity information to switch 802.

  When the frame timing information indicates an idle period, the switch 802 outputs the INI to the downlink signal modulation unit 104 and outputs the directivity information of the INI to the transmission directivity control unit 803.

  The transmission directivity control unit 803 controls the transmission directivity of the transmission antenna of the base station 800 based on the directivity information from the switch 802. As a control method at this time, a control method similar to the method used in the reception directivity control unit 801 can be used.

  Since the main configuration of the UE according to the present embodiment is the same as that of Embodiment 1, description thereof is omitted.

  Hereinafter, operations of the base station 800 and the UE 200 configured as described above will be described with reference to FIG. 3 again.

  In FIG. 3, a period (A) is an idle period in which uplink communication is not performed. In the period (A), the base station 800 switches the reception directivity by the reception directivity control unit 801 to receive a radio signal using a plurality of directivities, and the reception power estimation unit 106 , The received power of each RB is measured. Since the period (A) is an idle period during which no uplink signal is transmitted, the reception power measured by the reception power estimation unit 106 corresponds to the interference noise power from the adjacent cell in the corresponding reception direction. . Received power estimation section 106 estimates INI from the interference noise power of each RB, and outputs it to switcher 802 together with the directivity information at that time. As an example of the INI estimation method, as in the first embodiment, the INI can be set lower as the interference noise power is larger, and the INI can be set higher as the interference noise power is smaller.

  In the period (A), since the frame timing information indicates the idle period, the switch 802 outputs INI to the downlink signal modulation unit 104. Further, the switch 802 outputs corresponding directivity information to the transmission directivity control unit 803.

  In the period (B), the downlink signal modulation section 104 performs baseband modulation processing on each direction and INI of each RB output from the switch 802 and outputs the result to the transmission directivity control section 803. The transmission directivity control unit 803 gives a directivity similar to the reception directivity obtained by estimating the corresponding INI to the baseband modulated signal including the INI as the transmission directivity. Transmission directivity control section 803 outputs the baseband modulated signal subjected to transmission directivity control to downlink signal transmission section 105. The downlink signal transmission unit 105 transmits a transmission RF modulation signal including the INI of each RB to the UE.

  The transmission RF modulation signal transmitted from downlink signal transmission section 105 of base station 800 is received by a plurality of UEs. Below, although operation | movement of UE200 which is one of them is demonstrated, the same process is performed also in other UE. The downlink signal reception unit 201 receives a transmission RF modulation signal including the INI of each RB, obtains a reception baseband signal, and outputs the received baseband signal to the downlink signal demodulation unit 202. Downlink signal demodulation section 202 performs demodulation processing on the received baseband signal and extracts the INI of each RB. The downlink signal demodulation section 202 outputs the INI of each RB to the RB selection section 203.

  RB selection section 203 selects an RB for transmitting a pilot signal from INI and transmission data information. Since the method for selecting the transmission RB is the same as that in the first embodiment, the description thereof is omitted.

  UE 200 transmits a pilot signal for uplink CQI estimation in period (C) in FIG. Pilot signal generation section 206 generates a pilot signal for performing uplink CQI estimation. Based on the pilot signal transmission RB information output from RB selection section 203, transmission RB mapping section 205 maps the pilot signal to one or a plurality of corresponding RBs. Uplink signal transmission section 207 transmits a pilot signal from the transmission antenna.

  The pilot signal transmitted from UE 200 is received by the receiving antenna of base station 100. At this time, pilot signals simultaneously transmitted from UEs other than UE 200 are also received. The uplink signal receiving unit 101 converts the received signal into a baseband signal.

  Received power estimation section 106 estimates the received power of each RB and outputs the estimated power to switch 802. In the period (C), since the frame timing information indicates that the pilot signal is being transmitted, the switch 802 outputs the received power to the uplink CQI estimation unit 103.

  Similarly to Embodiment 1, uplink CQI estimation section 103 estimates the uplink CQI of each UE from the pilot signal of each UE. The uplink CQI estimation unit 103 outputs the estimated uplink CQI of each UE to the uplink RB allocation unit 107. The uplink RB allocation unit 107 performs frequency scheduling based on the uplink CQI of each UE, and allocates an RB for each UE to transmit an uplink signal.

  In the period (D), the base station 800 transmits a downlink signal including an “RB allocation notification signal” that specifies an RB to which each UE transmits an uplink signal.

  Each UE receives a downlink signal including an RB allocation notification signal, and reads an RB used for uplink signal transmission described in the RB allocation notification signal.

  In the period (E), the UE 200 transmits an uplink signal using the RB allocated from the base station 800.

  As described above, according to the present embodiment, base station 800 controls reception directivity by reception directivity control section 801, measures interference noise power for each direction, and measures interference noise measured for each direction. The different INIs set based on the power are notified to UEs located in the direction affected by the INI by the transmission directivity control unit 803. For this reason, even if there is an RB with a large interference power only in a specific direction, UEs located in the same direction can avoid the corresponding RB and transmit a pilot signal, which results in poor channel quality. In RB, CQI measurement is not performed, and CQI measurement accuracy can be improved. Further, since the INI set based on the interference noise power is not notified to the UE in the direction different from the direction of the RB where the interference noise power is large, a pilot signal can be transmitted using the RB. In addition, the efficiency of CQI estimation and frequency scheduling can be improved.

  In this embodiment, the INI is set based on the magnitude of the interference noise power. However, a threshold is set for the interference noise power. May be notified to each UE as INI that all candidate RBs have been labeled as “Pilot transmittable”. In this way, the UE that has received the INI can clearly distinguish between an RB that is highly affected by interference and cannot perform CQI measurement with high accuracy, and an RB that is less affected by interference and can perform CQI measurement with high accuracy. .

  In this embodiment, the INI is estimated for each direction, the same INI is notified for the same direction, and the different INI is notified for different directions. The directivity control unit 801 may have a function of estimating the direction in which the UE is located for each UE, and may transmit an INI in the corresponding direction. In this case, the signal flow is shown in FIG.

  In period (A) in FIG. 15, base station 800 estimates INI in each direction. At time (B), UE 200 transmits an access request signal requesting permission to perform transmission to base station 800. Base station 800 receives an access request signal transmitted from UE 200. Here, base station 800 has a function of estimating the arrival direction of the received signal, and estimates the arrival direction of the access request signal in period (C). Next, the base station estimates the direction in which the UE exists from the arrival direction of the access request signal, and transmits INI corresponding to that direction to UE 200 at time (D). In this way, the UE 200 can know the INI in the direction in which the UE 200 is located, and can transmit a pilot signal while avoiding the influence of interference.

(Embodiment 6)
The base station according to the sixth embodiment estimates interference noise power during a period in which an uplink signal is received. Thereby, even if it is not an idle period, interference noise electric power can be estimated.

  FIG. 16 is a block diagram showing a main configuration of base station 900 according to Embodiment 6 of the present invention. In the description of the present embodiment, the same components as those in FIG.

  The difference from Embodiment 1 is that base station 900 of this embodiment further includes replica generation section 901 and cancellation section 902.

  Based on the interference estimation timing information, replica generation section 901 generates reception replica signals for the uplink signals of all candidate RBs from the uplink signals and propagation path estimation values of each RB demodulated by uplink signal demodulation section 102. . Here, the interference estimation timing information is information indicating whether it is timing to estimate interference noise, and the replica generation unit 901 generates and generates a reception replica signal when the interference estimation timing information indicates interference estimation timing. The received reception replica signal is output to the cancel unit 902.

  The cancel unit 902 cancels the reception replica signal generated by the replica generation unit 901 from the reception signal obtained from the uplink signal reception unit 101. Since the uplink signal component is removed from the received signal by this cancellation, the output of the cancel unit 902 corresponds to the interference noise component of the RB. Canceling section 902 outputs the interference noise component to received power estimating section 106.

  The switcher 108 switches the output destination of the reception power information estimated by the reception power estimation unit 106 according to the interference estimation timing information. When the interference estimation timing information indicates the interference estimation timing, the switch 108 outputs the received power information to the downlink signal modulation section 104 as an INI notification signal. On the other hand, when it is not the interference estimation timing, the switch 108 transmits the received power information to the uplink CQI estimation unit 103.

  Since the main configuration of the UE according to the present embodiment is the same as that of Embodiment 1, description thereof is omitted.

  Hereinafter, operations of the base station 900 and the UE 200 configured as described above will be described.

  FIG. 17 is a diagram illustrating an example of a signal flow of uplink / downlink communication in the present embodiment.

  In FIG. 17, a period (A) is a period that is the interference estimation timing. In this period (A), uplink signals are transmitted. In period (A), replica generation section 901 in base station 900 generates an uplink signal reception replica signal from the uplink signal and propagation path information obtained by uplink signal demodulation section 102. Canceling section 902 cancels the received replica signal created by replica generating section 901 from the received signal obtained by uplink signal receiving section 101, and outputs the received signal after cancellation to received power estimating section 106.

  Thereby, in period (A), since the signal from which the uplink signal was canceled is input to reception power estimation section 106, the reception power measured by reception power estimation section 106 corresponds to interference noise power. become. Similar to Embodiment 1, received power estimation section 106 estimates INI from the interference noise power of each RB, and outputs it to switch 108.

  In the period (A), since the interference estimation timing information indicates the interference estimation timing, the switch 108 outputs INI to the downlink signal modulation unit 104.

  Similarly to the first embodiment, in the period (B), the base station 900 transmits a transmission RF modulation signal including the INI of each RB to each UE, and the UE 200 that has received the transmission RF modulation signal RB selection section 203 selects an RB that transmits a pilot signal from the INI of each RB and transmission data information, and the pilot signal is transmitted from UE 200 to base station 900 using the selected RB.

  In the period (C), the reception power estimation unit 106 of the base station 900 estimates the reception power of each RB and outputs it to the switch 108. In the period (C), the interference estimation timing information indicates that it is not the interference estimation timing, so the replica generation unit 901 and the cancellation unit 902 do not operate. The switch 108 outputs the received power to the uplink CQI estimation unit 103.

  Similarly to Embodiment 1, uplink CQI estimation section 103 estimates the uplink CQI of each UE from the pilot signal of each UE. The uplink CQI estimation unit 103 outputs the estimated uplink CQI of each UE to the uplink RB allocation unit 107. The uplink RB allocation unit 107 performs frequency scheduling based on the uplink CQI of each UE, and allocates an RB for each UE to transmit an uplink signal.

  In period (D) and period (E), as in Embodiment 1, base station 900 transmits a downlink signal including an RB allocation notification signal in which each UE specifies an RB for transmitting the uplink signal. , UE 200 transmits an uplink signal using the RB allocated from base station 900.

  As described above, according to the present embodiment, base station 900 further includes replica generation section 901 and cancellation section 902, so that interference noise power can be reduced even in an idle period in which no pilot signal is transmitted. Estimation can be performed.

  One aspect of the radio base station apparatus of the present invention estimates the channel quality with the radio terminal apparatus based on the reception quality of the reference signal transmitted from the radio terminal apparatus, and based on the channel quality A radio base station apparatus for controlling uplink transmission of the radio terminal apparatus, wherein received power estimation means for measuring interference noise power at the time of reception, and of the measured interference noise power, from the radio terminal apparatus Transmitting means for transmitting information on interference noise power for a frequency band which is interference noise power measured in a period before receiving the reference signal and is a candidate for transmitting the reference signal to the wireless terminal device; The structure which comprises is taken.

  According to this configuration, when there are a plurality of frequency bands that can be used by the wireless terminal device of the communication partner, the wireless terminal device does not transmit a pilot signal that is a reference signal in all candidate frequency bands, Since the pilot signal is transmitted by narrowing down to a frequency band in which the noise power is relatively small and the channel quality is estimated to be good, the power consumption of the radio terminal apparatus can be reduced, and the radio base station apparatus Since the CQI estimation can be performed by focusing on the transmitted frequency band, the CQI can be estimated efficiently, and the CQI estimation time can be shortened.

  One aspect of the radio base station apparatus of the present invention further comprises uplink CQI estimation means for estimating an uplink channel quality indicator, and the radio terminal among the interference noise power measured by the received power estimation means Interference noise power measured in a period before receiving the reference signal from the apparatus is transmitted to the wireless terminal apparatus via the transmission unit, while the reference signal from the wireless terminal apparatus is received The interference noise power measured in (1) adopts a configuration used for estimation by the CQI estimation means.

  According to this configuration, the received power of the pilot signal is measured using the received power measuring unit that measures the interference noise power during the idle period when the pilot signal is not transmitted, and the radio base station is based on the received power. The device can perform CQI estimation.

  In one aspect of the radio base station apparatus of the present invention, the transmission means is information on the interference noise power for the candidate frequency band in a frequency band different from a frequency band in which the radio terminal apparatus transmits the reference signal. The structure which transmits is taken.

  According to this configuration, for example, the radio terminal apparatus can receive information on interference noise power transmitted from the radio base station apparatus while transmitting an uplink data signal, so that a reduction in uplink line throughput can be achieved. Can be avoided.

  In one aspect of the radio base station apparatus of the present invention, the transmission means is information on the interference noise power for the candidate frequency band in the same frequency band as the frequency band in which the radio terminal apparatus transmits the reference signal. The structure which transmits is taken.

  According to this configuration, when the wireless terminal device receives the information on the interference noise power and transmits the pilot signal that is the reference signal, the wireless terminal device does not receive the information on the interference noise power until the wireless terminal device receives the information on the interference noise power. Since there is a high possibility that the uplink frequency band is an empty channel without transmitting a pilot signal from the apparatus, it is possible to reliably transmit interference noise power information.

  In one aspect of the radio base station apparatus of the present invention, the transmission means allocates the information of the interference noise power for the candidate frequency band to the transmission power of a signal in a part of the frequency band of the downlink frequency band. Use a configuration to transmit.

  One aspect of the radio base station apparatus of the present invention employs a configuration in which the transmission means makes the transmission power inversely proportional to the interference noise power.

  According to these configurations, the radio terminal apparatus can estimate the interference noise power in the uplink frequency band by monitoring the power of the received signal without performing demodulation processing of the received signal. By demodulating the signal, it is possible to shorten the time required to select a frequency band in which the interference noise power is small and the channel quality is estimated to be good as compared with the case of estimating the interference noise power in the uplink frequency band.

  One aspect of the radio base station apparatus of the present invention is characterized in that the received power estimation means includes a control means for switching a reception direction, and the interference noise power for the candidate frequency band is switched for each direction by switching the reception direction. And the transmission means transmits the information on the interference noise power for the candidate frequency band for each direction in a corresponding direction.

  According to this configuration, when a radio base station apparatus is affected by interference from an adjacent cell, even if there is a frequency band in which interference noise power is large in a certain direction, the radio terminal apparatus Since the pilot signal can be prevented from being transmitted, the measurement accuracy of CQI measured in the radio base station apparatus can be improved.

  One aspect of the radio base station apparatus of the present invention further comprises position estimation means for estimating a direction in which the radio terminal apparatus is located, and the control means is configured to receive the reception direction in a direction in which the radio terminal apparatus is located. The configuration is used to switch between.

  According to this configuration, the wireless terminal device of the communication partner can reliably select a frequency band with low interference noise power and good channel quality.

  One aspect of the radio base station apparatus of the present invention includes a demodulating unit that demodulates received data from a received signal, a replica generating unit that generates an uplink replica signal from the received data demodulated by the demodulating unit, And a canceling means for canceling the replica signal from the received signal.

  According to this configuration, since the interference noise power can be estimated even in a period other than the idle period in which no pilot signal is transmitted, the CQI estimation time can be shortened.

  One aspect of the wireless terminal device of the present invention is based on information on interference noise power for a candidate frequency band transmitted from a wireless base station device, and a selection unit that selects a frequency band for transmitting a reference signal. And a transmission means for transmitting the reference signal using the frequency band.

  According to this configuration, the radio terminal apparatus does not transmit a pilot signal that is a reference signal in all candidate frequency bands, but in a frequency band in which interference noise power is relatively small and channel quality is estimated to be good. Since the pilot signal is transmitted after being narrowed down, the power consumption of the wireless terminal device can be reduced, and the wireless base station device can perform the CQI estimation by narrowing down to the frequency band in which the pilot signal is transmitted. The estimation can be performed efficiently, and the CQI estimation time can be shortened.

  One aspect of the wireless terminal device of the present invention employs a configuration in which the selecting means selects a frequency band for transmitting the reference signal from the interference noise power and the QoS of data to be transmitted.

  One aspect of the wireless terminal device of the present invention employs a configuration in which a frequency band with a lower interference noise power is selected as the QoS of transmission data is higher.

  According to these configurations, when the QoS is high and the allowable error is small, the uplink noise signal is reliably transmitted by selecting a frequency band in which the interference noise power is small and the channel quality is estimated to be good. If the QoS level is low and some transmission errors can be tolerated, an estimated frequency band with high interference noise power and poor channel quality is selected, and another wireless terminal device with high QoS is selected. Since the frequency band estimated to have good channel quality can be used, the frequency utilization efficiency of the entire system can be improved.

  One aspect of the wireless terminal device of the present invention adopts a configuration in which a frequency band for transmitting the reference signal is selected from the interference noise power and the distance between the device itself and the wireless base station device.

  One aspect of the wireless terminal device of the present invention employs a configuration in which a frequency band with a smaller interference noise power is selected as the distance between the device itself and the wireless base station device increases.

  According to these configurations, a radio terminal device that is far from the radio base station device transmits a pilot signal in a frequency band that is estimated to have low interference noise power and good channel quality, thereby improving channel quality. Since a frequency band estimated to be good is assigned to the wireless terminal device, the possibility of good communication increases even when the received power is reduced due to the distance.

  One aspect of the wireless terminal device of the present invention employs a configuration in which a frequency band having a smaller interference noise power is selected as the distance between the device itself and the wireless base station device is shorter.

  According to this configuration, a radio terminal apparatus that is close to the radio base station apparatus transmits a pilot signal in a frequency band that is estimated to have low interference noise power and good channel quality, thereby improving channel quality. Therefore, the uplink data signal can be transmitted by MCS (Modulation and Coding Scheme) having a high transmission rate.

  One aspect of the wireless terminal apparatus of the present invention employs a configuration in which a frequency band for transmitting the uplink reference signal is selected from the interference noise power and the moving speed of the own apparatus.

  One aspect of the wireless terminal device of the present invention adopts a configuration in which the frequency band with the smaller interference noise power is selected as the moving speed of the own device is lower.

  According to these configurations, a radio terminal device having a high movement speed and a large change in channel quality transmits a pilot signal in a frequency band having a large interference noise power, and a radio signal having a low movement speed and a little change in channel quality. The terminal device transmits a pilot signal in a frequency band with low interference noise power, so that a wireless terminal device with little change in channel quality avoids continuing to transmit data in a frequency band with high interference noise power. In addition, since it is possible to reliably transmit an uplink data signal in a frequency band with low interference noise power, it is possible to suppress a decrease in throughput.

  One aspect of the wireless terminal device of the present invention employs a configuration in which, when transmission data is retransmission data, a frequency band with a low interference noise power is selected.

  According to this configuration, when transmitting retransmission data, the radio terminal apparatus can transmit a pilot signal by selecting a frequency band that is estimated to have low interference noise power and good channel quality. The certainty of data transmission can be improved.

  One aspect of the wireless terminal device of the present invention employs a configuration in which the number of frequency bands to be selected is increased as the reference signal is transmitted in a frequency band in which the interference noise power is large.

  According to this configuration, when a pilot signal is transmitted using a frequency band in which interference noise power is large and channel quality is estimated to be not so good, the pilot signal is transmitted using a larger number of frequency bands. Therefore, the effect of frequency diversity can be obtained.

  One aspect of the wireless terminal device of the present invention employs a configuration in which a plurality of transmission antennas are provided, and the reference signal is transmitted from the plurality of transmission antennas using different frequency bands selected.

  According to this configuration, when the frequency band selected by the wireless terminal device is separated, a pilot signal can be transmitted in a different frequency band from each antenna, and the pilot signal transmitted from the wireless terminal device is When it is assumed that the signal is transmitted from a single antenna, it can be regarded as a single carrier signal using continuous RBs, so that it is possible to avoid the occurrence of a power peak and reduce the peak power vs. average power. , ACLR can be reduced.

  One aspect of the wireless communication system of the present invention estimates the channel quality with the radio terminal device based on the reception quality of a reference signal transmitted from the radio terminal device, and based on the channel quality A radio base station apparatus for controlling uplink transmission of the radio terminal apparatus, wherein the received power estimation means for measuring interference noise power at the time of reception, and the measured interference noise power from the radio terminal apparatus Transmission means for transmitting interference noise power information about a frequency band that is interference noise power measured in a period before receiving a reference signal and is a candidate for transmitting the reference signal to the wireless terminal device; A radio base station apparatus comprising: a selection means for selecting a frequency band for transmitting a reference signal based on interference noise power information for a candidate frequency band transmitted from the radio base station apparatus; A configuration that includes a wireless terminal device comprising a transmitting means for transmitting a reference signal with the selected frequency band, and the.

  One aspect of the channel quality indicator estimation method of the present invention includes a step in which a radio base station apparatus measures interference noise power at the time of reception, and a radio terminal apparatus out of the interference noise power measured by the radio base station apparatus. Transmitting interference noise power information about the frequency band that is the interference noise power measured in the period before receiving the reference signal from the frequency band that is a candidate for transmitting the reference signal to the wireless terminal device; The wireless terminal device selects a frequency band for transmitting the reference signal from the interference noise power information for the candidate frequency band, and the wireless terminal device transmits the reference signal using the selected frequency band. A step in which the radio base station apparatus measures the received power of the reference signal, and the radio base station apparatus uses the received power of the reference signal, A step of serial reference signal to estimate the channel quality indicator of the uplink transmitted, and to have.

  According to these, when there are a plurality of frequency bands that can be used by the wireless terminal device of the communication partner, the wireless terminal device does not transmit a pilot signal that is a reference signal in all candidate frequency bands, Considering the influence of adjacent cell interference in the station apparatus, the pilot signal is transmitted only in the frequency band where the interference noise power is relatively small and the channel quality is estimated to be good, so that the power consumption of the radio terminal apparatus is reduced. In addition, since the radio base station apparatus can perform CQI estimation focusing on the frequency band in which the pilot signal is transmitted, the CQI can be estimated efficiently and the CQI estimation time can be shortened.

  The present invention provides a radio base station apparatus, a radio terminal apparatus, a radio communication system, and a channel quality indicator estimation method that can reduce CQI estimation time for frequency scheduling while reducing power consumption in the radio terminal apparatus, For example, it is useful for a radio base station apparatus, a radio terminal apparatus, a radio communication system, and a channel quality indicator estimation method that perform frequency scheduling by transmitting and receiving pilot signals for radio communication channel quality estimation.

The block diagram which shows the principal part structure of the base station which concerns on Embodiment 1 of this invention. The block diagram which shows the principal part structure of UE which concerns on Embodiment 1. FIG. The figure which shows an example of the flow of an uplink signal and a downlink signal The figure which shows the relationship between the desired QoS level of transmission data, and INI The block diagram which shows the principal part structure of the base station which concerns on Embodiment 2 of this invention. The block diagram which shows the principal part structure of UE which concerns on Embodiment 2. FIG. The figure for demonstrating an uplink INI notification frame The figure which shows the relationship between the transmission power of an INI notification frame, and a downlink frequency The block diagram which shows the principal part structure of the base station which concerns on Embodiment 3 of this invention. The block diagram which shows the principal part structure of UE which concerns on Embodiment 3. FIG. The figure which shows an example of the flow of an uplink signal and a downlink signal The block diagram which shows the principal part structure of UE which concerns on Embodiment 4 of this invention. The figure which shows the mode of the adjacent cell interference with the base station which concerns on this Embodiment 5. FIG. 10 is a block diagram showing a main configuration of a base station according to Embodiment 5 Signal flow diagram for explaining operations of base station and UE according to embodiment 5 A block diagram showing a main configuration of a base station according to the sixth embodiment The figure which shows an example of the flow of an uplink signal and a downlink signal The figure which shows CQI in each RB of the conventional base station and each UE connected to it Diagram for explaining neighboring cell interference in cellular system

Explanation of symbols

101 uplink signal receiving unit 102 uplink signal demodulating unit 103 uplink CQI estimating unit 104 downlink signal modulating unit 105, 301 downlink signal transmitting unit 106 received power estimating unit 107 uplink RB assigning unit 108, 802 switcher 201, 401 downlink signal receiving section 202 downlink signal demodulating section 203 RB selecting section 204 uplink signal modulating section 205 transmission RB mapping section 206 pilot signal generating section 207, 701 uplink signal transmitting section 402 INI estimating section 501 INI notification signal modulating section 502 INI notification signal transmission unit 503, 601 transmission / reception switcher 602 INI notification signal reception unit 603 INI notification signal demodulation unit 801 reception directivity control unit 803 transmission directivity control unit 901 replica generation unit 902 cancel Part

Claims (22)

Radio that estimates the channel quality with the radio terminal device based on the reception quality of the reference signal transmitted from the radio terminal device, and controls uplink transmission of the radio terminal device based on the channel quality A base station device,
A reception power estimation means for measuring interference noise power during reception;
Among the measured interference noise powers, interference noise powers measured in a period before receiving the reference signal from the wireless terminal device, and interference noise for a frequency band that is a candidate for transmitting the reference signal Transmitting means for transmitting power information to the wireless terminal device;
A radio base station apparatus comprising: An uplink CQI estimation means for estimating an uplink channel quality indicator,
Of the interference noise power measured by the received power estimation means, the interference noise power measured in a period before receiving the reference signal from the wireless terminal apparatus is transmitted to the wireless terminal apparatus via the transmitting means. The radio base station apparatus according to claim 1, wherein interference noise power measured during a period in which the reference signal is received from the radio terminal apparatus is used for estimation by the CQI estimation unit. 2. The radio base station apparatus according to claim 1, wherein the transmission unit transmits information on the interference noise power for the candidate frequency band in a frequency band different from a frequency band in which the radio terminal apparatus transmits the reference signal. . 2. The radio base station apparatus according to claim 1, wherein the transmission unit transmits the information on the interference noise power for the candidate frequency band in the same frequency band as the frequency band in which the radio terminal apparatus transmits the reference signal. . The radio base station apparatus according to claim 1, wherein the transmission section allocates and transmits the interference noise power information about the candidate frequency band to a transmission power of a signal in a part of a frequency band of a downlink frequency band. The radio base station apparatus according to claim 5, wherein the transmission unit makes the transmission power inversely proportional to the interference noise power. The received power estimation means comprises control means for switching the reception direction,
Switching the reception direction, estimating the interference noise power for the candidate frequency band for each direction,
The radio base station apparatus according to claim 1, wherein the transmission section transmits information on the interference noise power for the candidate frequency band for each direction in a corresponding direction. Position estimation means for estimating a direction in which the wireless terminal device is located,
The radio base station apparatus according to claim 7, wherein the control unit switches the reception direction to a direction in which the radio terminal apparatus is located. Demodulation means for demodulating the received data from the received signal;
Replica generation means for generating an uplink replica signal from the reception data demodulated by the demodulation means;
The radio base station apparatus according to claim 1, further comprising cancellation means for canceling the replica signal from the received signal. Selection means for selecting a frequency band for transmitting a reference signal based on interference noise power information about the candidate frequency band transmitted from the radio base station apparatus;
A transmission means for transmitting the reference signal using the selected frequency band;
A wireless terminal device comprising: The radio terminal apparatus according to claim 10, wherein the selection unit selects a frequency band for transmitting the reference signal from the interference noise power and QoS of data to be transmitted. The radio terminal apparatus according to claim 11, wherein the selection unit selects a frequency band in which the interference noise power is smaller as the QoS of transmission data is higher. The radio terminal apparatus according to claim 10, wherein the selection unit selects a frequency band for transmitting the reference signal from the interference noise power and a distance between the radio apparatus and the radio base station apparatus. The radio terminal apparatus according to claim 13, wherein the selection unit selects a frequency band in which the interference noise power is smaller as the distance between the radio apparatus and the radio base station apparatus increases. The radio terminal apparatus according to claim 13, wherein the selection unit selects a frequency band in which the interference noise power is smaller as a distance between the own apparatus and the radio base station apparatus is shorter. The radio terminal apparatus according to claim 10, wherein the selection section selects a frequency band for transmitting the uplink reference signal from the interference noise power and a moving speed of the own apparatus. The radio terminal apparatus according to claim 16, wherein the selection unit selects a frequency band in which the interference noise power is smaller as the moving speed of the own apparatus is lower. The radio terminal apparatus according to claim 10, wherein when the transmission data is retransmission data, the selection unit selects a frequency band in which the interference noise power is small. The radio terminal apparatus according to claim 10, wherein the selection unit increases the number of frequency bands to be selected as the reference signal is transmitted in a frequency band in which the interference noise power is large. A plurality of transmitting antennas,
The wireless terminal apparatus according to claim 10, wherein the reference signal is transmitted from the plurality of transmission antennas using different frequency bands selected. Radio that estimates the channel quality with the radio terminal device based on the reception quality of the reference signal transmitted from the radio terminal device, and controls uplink transmission of the radio terminal device based on the channel quality A reception power estimation means for measuring interference noise power at the time of reception and interference measured in a period before receiving the reference signal from the wireless terminal device among the measured interference noise power A radio base station apparatus comprising: transmission means for transmitting to the radio terminal apparatus information on interference noise power for a frequency band that is noise power and is a candidate for transmitting the reference signal;
Selection means for selecting a frequency band for transmitting a reference signal based on information on interference noise power for the candidate frequency band transmitted from the radio base station apparatus, and transmission for transmitting a reference signal using the selected frequency band A wireless communication system. A radio base station apparatus measuring interference noise power at the time of reception;
Of the measured interference noise power, a radio base station apparatus is an interference noise power measured in a period before receiving a reference signal from a radio terminal apparatus, and a frequency band that is a candidate for transmitting the reference signal Transmitting interference noise power information about the to the wireless terminal device;
The wireless terminal device selects a frequency band for transmitting the reference signal from information on interference noise power for the candidate frequency band; and
A wireless terminal device transmitting the reference signal using a selected frequency band;
A radio base station apparatus measuring received power of the reference signal;
A radio base station apparatus, from the received power of the reference signal, estimating an uplink channel quality indicator from which the reference signal is transmitted;
A channel quality indicator estimation method comprising:

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