JP2012253486A - Radio communication device and radio communication program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication device and a radio communication program, not decreasing throughput performance of a physical uplink shared channel if a user terminal periodically feeds back to a pico base station a subframe-type-by-type channel quality index.SOLUTION: In a heterogeneous network, a radio communication device 600 includes: a grouping unit 650 for grouping radio terminals; and when the ratio of radio resources is a predetermined threshold or greater, a quality feedback radio resource allocation unit 660 for generating index allocation information for radio terminals subordinate to a first group to feed back channel quality information measured at the transmission timing of a first-type subframe, and for generating index allocation information for radio terminals subordinate to a second group to feed back channel quality information measured at the transmission timing of a second-type subframe.

Description

  The present invention relates to a wireless communication apparatus and a wireless communication program.

  In recent years, in order to improve the quality of wireless communication in a local area and offload the traffic of wireless communication in a macro area, a heterogeneous network composed of macro base stations, pico base stations, and the like has attracted attention. In a heterogeneous network, a desired wave from a pico base station to a user terminal may be interfered with by an interference wave transmitted by a macro base station.

  Also, in 3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) Rel-10, a physical downlink control channel (Physical Downlink Channel) to a user terminal (User Equipment, UE) transmitted from a pico base station to a user terminal (User Equipment, UE). In order to avoid interference, Time Domain-Inter Cell Interference Coordination (TD-ICIC) has been studied.

  When TD-ICIC is applied to a heterogeneous network, transmission timing of the physical downlink shared channel (Physical Downlink Shared Channel, PDSCH) and the physical uplink shared channel (Physical Uplink Shared Channel, PUSCH) is all-blank. -It can be limited by a subframe (Almost Blank Subframe, ABS). Also, the user terminal of the pico base station can measure a channel quality indicator (Channel Quality Indicator, CQI) for each subframe type (normal subframe, ABS).

JP 2011-15023 A

3GPP, TS 36.211 V9.1.0, “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation (Release 9),” March 2010. 3GPP, TS 36.213 V9.1.0, “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures (Release 9),” March 2010.

  However, when the user terminal periodically feeds back the channel quality indicator to the pico base station (Periodic CQI), the user terminal feeds back the channel quality indicator to the pico base station using the radio resource of the physical uplink channel. For this reason, when the user terminal simply feeds back the channel quality indicator for each subframe type, the amount of radio resources for feeding back the channel quality indicator increases, so that the physical uplink multiplexed on the feedback channel and the frequency axis There is a problem that the throughput performance of the shared channel is lowered.

  The present invention has been made in view of the above points, and even when the user terminal periodically feeds back a channel quality index for each subframe type to the pico base station, the throughput performance of the physical uplink shared channel does not deteriorate. An object is to provide a wireless communication apparatus and a wireless communication program.

  The present invention has been made to solve the above-described problem, and mutually excludes a first type subframe in which data transmission is not restricted and a second type subframe in which data transmission is restricted. In a heterogeneous network comprising: a macro base station that transmits at a transmission timing; and a non-macro base station having a downlink channel that receives interference from the first type subframe and the second type subframe. A ratio calculation unit that calculates a ratio of radio resources of the uplink channel to which shared channel data other than the channel quality index of the downlink channel is allocated to all radio resources of a predetermined unit of the uplink channel; and the ratio is equal to or greater than a predetermined threshold The channel measured at the timing when the first type subframe is transmitted. A grouping unit that groups the wireless terminals into a first group that transmits a channel quality indicator and a second group that transmits the channel quality indicator measured at a timing when the second type subframe is transmitted When the ratio is equal to or greater than the predetermined threshold, index assignment information is sent to the radio terminals belonging to the first group so as to feed back the channel quality index measured at the transmission timing of the first type subframe. A channel quality feedback radio resource for generating index assignment information for radio terminals belonging to the second group so as to feed back the channel quality index measured at the transmission timing of the second type subframe. The index generated by the allocation unit and the channel quality feedback radio resource allocation unit The person information, the a wireless communication apparatus characterized by comprising: a downlink channel information allocation unit to be transmitted to the wireless terminals communicating with non-macro base stations.

  Also, in the present invention, the grouping unit may determine a ratio between the number of all subframes in a predetermined unit of the first type subframe and the second type subframe and the number of subframes of the second type subframe. Accordingly, the wireless communication apparatus groups the wireless terminals.

  Also, the present invention is the wireless communication apparatus, wherein the grouping unit groups the wireless terminals based on the downlink channel reception intensity or signal-to-interference noise power ratio.

  The present invention also provides a macro base station that transmits a first type subframe in which data transmission is not restricted and a second type subframe in which data transmission is restricted at mutually exclusive transmission timings, A non-macro base station having a downlink channel that receives interference from the type 1 subframe and the type 2 subframe, and a predetermined unit of the uplink channel of the non-macro base station in a computer of a wireless communication apparatus in a heterogeneous network A procedure for calculating a ratio of the radio resources of the uplink channel to which shared channel data other than the channel quality index of the downlink channel is allocated to all the radio resources, and when the ratio is equal to or greater than a predetermined threshold, Transmit the channel quality indicator measured at the timing when the subframe is transmitted A first group, a second group for transmitting the channel quality indicator measured at a timing at which the second type subframe is transmitted, a procedure for grouping the wireless terminals, and the ratio is a predetermined threshold value If so, index assignment information is generated for the radio terminals belonging to the first group so as to feed back the channel quality indicator measured at the transmission timing of the first type subframe, and the second A procedure for generating index allocation information for wireless terminals belonging to the second group so as to feed back the channel quality index measured at the transmission timing of the seed subframe, and the generated index allocation information is the non-macro And a procedure for transmitting to a wireless terminal communicating with a base station.

  According to the present invention, the wireless terminals are grouped based on the ratio of the wireless resources, and the channel quality indicator measured at the transmission timing of the first type subframe is fed back by the wireless terminals belonging to the first group, The wireless terminals belonging to the second group feed back the channel quality indicator measured at the transmission timing of the two types of subframes. Therefore, the channel quality index of the number of reports controlled for each group is fed back from the radio terminals grouped according to the ratio of radio resources. Thereby, the wireless communication apparatus can prevent the throughput performance of the physical uplink shared channel from being deteriorated even when the user terminal periodically feeds back the channel quality index for each subframe type to the pico base station.

It is a figure showing the example of a heterogeneous network in one Embodiment of this invention. It is a figure showing the example of ABS with which data transmission is restrict | limited in one Embodiment of this invention. It is a figure showing the example of a structure of the radio | wireless communication apparatus in one Embodiment of this invention.

  An embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an example of a heterogeneous network. The wireless communication system includes a macro base station 100, a pico base station 300, and a CRE terminal 500 (user terminal).

  The macro base station 100 forms a macro cell 200 and performs radio communication with a radio terminal (not shown) in the macro cell 200.

  The pico base station 300 forms a pico cell 400 in the macro cell 200. Further, the pico base station 300 expands the pico cell 400 by cell range expansion (Cell Range Expansion, CRE) to form an extended pico cell 410. The pico base station 300 performs radio communication with the CRE terminal 500 located in the extended pico cell 410. In addition, the pico base station 300 performs radio communication with a radio terminal (not shown) (hereinafter referred to as “non-CRE terminal”) in the pico cell 400.

  In the radio terminal in the pico cell 400, “reception strength of the reference signal (desired wave) from the pico base station 300”> “reception strength of the reference signal (interference wave) from the macro base station 100” is satisfied. Here, the reception strength of the reference signal is, for example, Reference Signal Received Power (RSRP).

  On the other hand, in the CRE terminal 500 in the extended pico cell 410, the cell range extension causes “reference signal (desired wave) reception intensity from the pico base station 300 + bias value of the pico base station 300”> “from the macro base station 100” Of the reference signal (interference wave) + bias value of the macro base station 100 ”. In general, the bias value of the pico base station 300 and the bias value of the macro base station 100 are decibel (dB) values of 0 or more, and the bias value of the pico base station 300> the bias value of the macro base station 100.

  Note that the reception strength of the reference signal is, for example, Reference Signal Received Power (RSRP).

  The CRE terminal 500 is a wireless terminal that provides a wireless service from the pico base station 300, and is located in the extended pico cell 410 extended by cell range extension. The CRE terminal 500 performs radio communication with the pico base station 300 via the uplink channel and the downlink channel of the pico base station 300. Hereinafter, the description will be continued assuming that the uplink channel and downlink channel (desired wave) of the pico base station 300 receive interference from the uplink channel and downlink channel (interference wave) of the macro base station 100.

  FIG. 2 shows an example of ABS in which data transmission is restricted. In FIG. 2, as an example, in a predetermined number of subframes (for example, 40 subframes), normal subframes in which data transmission is not restricted via the uplink channel and downlink channel of the macro base station 100, and data Transmission timing mutually exclusive between the macro base station 100 and another wireless terminal (not shown) with a subframe (ABS) whose transmission is restricted (ABS ratio 50% for 40 subframes) The description will be continued assuming that it is being transmitted. Note that since the ABS is a subframe in which data transmission is restricted, the macro base station and the wireless terminal cannot communicate using the ABS.

  At the timing of normal subframes where data transmission is not restricted, the uplink channel and downlink channel (desired wave) of the pico base station 300 are subject to strong interference from the uplink channel and downlink channel (interference wave) of the macro base station 100. receive. On the other hand, at the ABS timing where data transmission is restricted, the uplink channel and the downlink channel of the macro base station 100 do not exist, so the uplink channel and the downlink channel of the pico base station 300 are the uplink channel and the downlink channel of the macro base station 100. No interference from downlink channel.

  Therefore, the CRE terminal 500 and the non-CRE terminal feed back the channel quality indicator (CQI) to the pico base station 300 for each subframe type based on the feedback instruction transmitted from the pico base station 300. Here, the feedback instruction includes, for example, the subframe type (normal subframe, ABS) for which the channel quality indicator is measured, and an offset indicating the position of the subframe in which the channel quality indicator is transmitted in the subframe group. Report of the channel quality indicator included in the subframe to feed back the value, the transmission interval (transmission timing) at which the channel quality indicator is transmitted, and the channel quality indicator measured at the timing at which the normal subframe is transmitted A number (0 or 1) and the number of reports (0 or 1) of the channel quality indicator included in the subframe for feeding back the channel quality indicator measured at the timing at which the ABS is transmitted. .

Next, a configuration example of the wireless communication device will be described.
FIG. 3 shows a configuration example of the wireless communication device. Radio communication apparatus 600 is provided in pico base station 300 (see FIG. 1). The wireless communication apparatus 600 includes a pattern acquisition unit 610, a terminal information acquisition unit 620, an uplink channel information allocation unit 630, a ratio calculation unit 640, a grouping unit 650, a channel quality feedback radio resource allocation unit 660, A downlink channel information allocation unit 670.

  Each unit includes, for example, a central processing unit and a storage unit (memory). Further, each unit may be an ASIC (Application Specific Integrated Circuit).

  The pattern acquisition unit 610 uses information indicating the ABS transmission timing (hereinafter referred to as “ABS pattern information”) in 40 subframes (see FIG. 2), for example, the macro base station 100 (see FIG. 1) using the X2 interface. The received ABS pattern information is transferred to the grouping unit 650.

  The terminal information acquisition unit 620 obtains information indicating the reception strength of the reference signal from the macro base station 100 and information indicating the reception strength of the reference signal from the pico base station 300 from the CRE terminal 500 (see FIG. 1) and Each information received from a non-CRE terminal (not shown) is transferred to the downlink channel information allocation unit 670 in association with the wireless terminal. Terminal information acquisition section 620 calculates the difference between the reception intensity from macro base station 100 and the reception intensity from pico base station 300 (hereinafter referred to as “reception intensity difference”), and indicates the calculated reception intensity difference Is output to the grouping unit 650.

  In addition, when the information indicating the reception strength cannot be acquired from some wireless terminals, the terminal information acquisition unit 620 acquires the information indicating the reception strength as the information indicating the reception strength at the wireless terminal. The minimum value or the maximum value of the reception strength in other wireless terminals that have been able to be transmitted may be transferred to the downlink channel information allocation unit 670.

  Uplink channel information allocation section 630 allocates data to be transmitted via the uplink channel (PUSCH) of pico base station 300 (see FIG. 1) to radio resources (scheduling). Also, uplink channel information allocation section 630 generates information indicating radio resources to which data transmitted via the uplink channel of pico base station 300 is allocated (hereinafter referred to as “uplink data allocation information”), and generates the generated uplink The data allocation information is output to the ratio calculation unit 640.

  The ratio calculation unit 640 determines the ratio of the number of resource blocks to which data is allocated to the total number of blocks (for example, 40 subframes) in a predetermined unit of the uplink channel radio resource of the pico base station 300 (hereinafter, “resource block ratio”). Is calculated based on the uplink data allocation information. The ratio calculation unit 640 outputs information indicating the calculated resource block ratio to the grouping unit 650 and the channel quality feedback radio resource allocation unit 660 for each predetermined period or subframe.

  Here, the ratio calculation unit 640 calculates the resource block ratio by a statistical method. For example, when information indicating the resource block ratio is output in a predetermined cycle, the ratio calculation unit 640 has an average number of resource blocks to which data is allocated for each predetermined period (hereinafter referred to as “ratio average value”). Based on the above, the resource block ratio is calculated. For example, when information indicating the resource block ratio is output for each subframe, the ratio calculation unit 640 calculates the resource block ratio based on the moving average value of the number of resource blocks to which data is allocated.

  The grouping unit 650 repeatedly determines whether or not to group a plurality of wireless terminals provided with wireless services from the pico base station 300 (see FIG. 1). More specifically, the grouping unit 650 determines whether to perform grouping at the current timing based on whether the grouping has been performed at the previous timing. Here, when information indicating the resource block ratio is input periodically or for each subframe, the grouping unit 650 receives information indicating the resource block ratio as to whether or not to perform grouping at the current timing. In synchronization with the timing to be determined, determination is made based on the resource block ratio (ratio average value or moving average value).

  The grouping unit 650 performs grouping at the previous timing, and when the resource block ratio is less than a threshold A (for example, 75 [%]), does not perform grouping at the current timing (grouping is performed). To cancel). On the other hand, when the grouping unit 650 executes grouping at the previous timing and the resource block ratio is equal to or greater than the threshold A, the grouping unit 650 determines to execute grouping at the current timing.

  In addition, when the grouping unit 650 does not perform grouping at the previous timing and the resource block ratio exceeds a threshold B (for example, 80 [%]), the grouping unit 650 executes grouping at the current timing. judge. On the other hand, when the grouping unit 650 does not execute grouping at the previous timing and the resource block ratio is equal to or less than the threshold B, the grouping unit 650 determines that the grouping is not performed (releases the grouping) at the current timing. To do. Here, it is assumed that threshold A ≦ threshold B.

 When the grouping unit 650 performs grouping, the grouping unit 650 performs pico transmission to the CRE terminal 500 (see FIG. 1) and the non-CRE terminal (not shown) based on the ABS pattern information and the information indicating the reception intensity difference. A plurality of wireless terminals to which wireless services are provided from the base station 300 (see FIG. 1) are grouped.

  More specifically, the grouping unit 650 calculates the number of wireless terminals to be grouped into non-CRE terminals based on the ABS pattern information. For example, in the ABS pattern information, it is assumed that X subframes out of 40 subframes (see FIG. 2) are ABS. In this case, the grouping unit 650 determines the reference number of wireless terminals to be grouped into non-CRE terminals based on the ratio (X / 40) of the number of subframes. (The wireless service is provided from the pico base station 300. Total number of wireless terminals) × (1−X / 40) ”.

  Further, grouping section 650 rearranges the wireless terminals to which the wireless service is provided from pico base station 300 in the order of the reception intensity difference based on the information indicating the reception intensity difference (sort). In addition, the grouping unit 650 selects wireless terminals whose reception intensity difference is equal to or greater than a threshold value C (for example, 8 [dB]).

  The grouping unit 650 determines whether or not the number of selected wireless terminals is equal to or less than the estimated number of wireless terminals to be grouped into non-CRE terminals. When the number of selected wireless terminals is equal to or less than the estimated number of wireless terminals to be grouped into non-CRE terminals, the grouping unit 650 groups the selected wireless terminals into non-CRE terminals (normal group) and selects them. The remaining wireless terminals that have not been grouped are grouped into CRE terminals (ABS group).

  On the other hand, when the number of selected wireless terminals is not less than or equal to the estimated number of wireless terminals to be grouped into non-CRE terminals, the grouping unit 650 increases the queue length of the buffer that stores data to be transmitted to the wireless terminals, or The selected wireless terminals are rearranged so that the reception intensity difference is in descending order. Further, grouping section 650 groups the estimated number of wireless terminals to be grouped into non-CRE terminals from the rearranged higher order wireless terminals into non-CRE terminals (normal group), and the remaining unselected Each wireless terminal is grouped into CRE terminals (ABS group).

  In this way, grouping section 650 associates information indicating the grouping result with the radio terminal, and outputs the information to channel quality feedback radio resource allocation section 660 and downlink channel information allocation section 670.

  Channel quality feedback radio resource allocation section 660 receives information indicating the resource block ratio and information indicating the grouping result. Channel quality feedback radio resource allocating section 660 includes radio resources (for example, transmission interval, offset value, resource ID) to which a channel quality index (CQI) transmitted via the uplink channel of pico base station 300 is allocated, and a channel A feedback instruction (hereinafter referred to as “index allocation information”) indicating the type of subframe (normal subframe, ABS) for which a quality index is measured, information indicating a resource block ratio, and a grouping result Generate based on information.

  For example, when radio terminals are not grouped by the grouping unit 650, the channel quality feedback radio resource allocating unit 660 determines that all radio terminals to which radio services are provided from the pico base station 300 are normal subframes and In order to feed back the ABS channel quality index to the pico base station 300, index allocation information is generated for all the radio terminals. Here, the radio resource allocating unit 660 for channel quality feedback uses, as index allocation information, a channel quality index feedback transmission interval, an offset value, and a resource ID, a normal subframe channel quality index, and an ABS channel. Define for each quality indicator.

  On the other hand, when radio terminals are grouped by grouping section 650, channel quality feedback radio resource allocation section 660 generates index allocation information based on information indicating the grouping result. More specifically, channel quality feedback radio resource allocation section 660 provides index allocation information to each non-CRE terminal so that each non-CRE terminal feeds back the channel quality index of the normal subframe to pico base station 300. Is generated. The channel quality feedback radio resource allocating unit 660 determines, as index allocation information, a channel quality index feedback transmission interval, an offset value, and a resource ID for the channel quality index of the normal subframe. Also, channel quality feedback radio resource allocation section 660 generates index allocation information for each CRE terminal so that each CRE terminal feeds back the ABS channel quality index to pico base station 300. The channel quality feedback radio resource allocating unit 660 determines, as index allocation information, a channel quality index feedback transmission interval, an offset value, and a resource ID for the ABS channel quality index.

  Thus, the non-CRE terminal feeds back the CQI measured at the transmission timing of the normal subframe. The CRE terminal feeds back the CQI measured at the ABS transmission timing. Therefore, the channel quality index of the number of reports controlled for each group is fed back from the radio terminals grouped according to the ratio of radio resources. As a result, the channel quality feedback radio resource allocating unit 660 can prevent the throughput performance of the physical uplink shared channel from being deteriorated.

  Downlink channel information allocation section 670, based on information indicating the reception strength of the reference signal, information indicating the grouping result, and index allocation information, data transmitted via the downlink channel of pico base station 300, Assign to radio resources. Here, downlink channel information allocation section 670 generates downlink data allocation information indicating radio resources to which data transmitted via the downlink channel of pico base station 300 is allocated. For example, the downlink data allocation information includes information indicating a modulation scheme.

  When the wireless terminals are not grouped by the grouping unit 650, the downlink channel information allocation unit 670 calculates a reception strength difference based on information indicating the reception strength of the reference signal. Further, the downlink channel information allocating unit 670 targets only the wireless terminals for which the calculated reception intensity difference is equal to or greater than the predetermined threshold E among the wireless terminals to which the wireless service is provided from the pico base station 300, to the macro base station 100. Downlink data allocation information is generated so as to allocate radio resources at the timing when normal subframes are transmitted from. Also, the downlink channel information allocating unit 670 allocates downlink data allocation so as to allocate radio resources at a timing at which ABS is transmitted from the macro base station 100 to all radio terminals to which radio services are provided from the pico base station 300. Generate information.

  On the other hand, when the radio terminals are grouped by the grouping unit 650, the downlink channel information allocating unit 670 is a radio resource at a timing at which a normal subframe is transmitted from the macro base station 100 for each non-CRE terminal. Is assigned to generate downlink data allocation information. In this way, the downlink channel information allocation section 670 can prevent the throughput performance of the physical uplink shared channel from deteriorating because the non-CRE terminal has high reception strength from the pico base station 300.

  Also, the downlink channel information allocating unit 670 generates downlink data allocation information by allocating radio resources at the timing at which the ABS is transmitted from the macro base station 100 to each CRE terminal. In this way, the downlink channel information allocating unit 670 may prevent the throughput performance of the physical uplink shared channel from being deteriorated even in the CRE terminal 500 (see FIG. 1) having low reception strength from the pico base station 300. it can.

  Downlink channel information allocation section 670 outputs downlink data allocation information to a radio communication section (not shown). The wireless communication unit performs wireless communication with the CRE terminal 500 and the non-CRE terminal based on the downlink data allocation information.

  As described above, the macro base station 100 that transmits a normal subframe in which data transmission is not restricted and an ABS in which data transmission is restricted at transmission timings mutually exclusive, the normal subframe, and the ABS. In a heterogeneous network comprising a pico base station 300 having a downlink channel (PDSCH) that is subject to interference, the wireless communication apparatus 600 is a predetermined unit (for example, 40 subframes) of the uplink channel (PUSCH) of the pico base station 300 A ratio calculation unit 640 that calculates a ratio of radio resources of the uplink channel to which shared channel data other than the channel quality index (CQI) of the downlink channel is allocated, and a resource block ratio is a predetermined threshold (for example, , Threshold A) or more, A first group (non-CRE terminal) that transmits the CQI measured at the timing when the multi-subframe is transmitted, and a second group (CRE terminal) that transmits the CQI measured at the timing when the ABS is transmitted And a grouping unit 650 that groups the wireless terminals, and a non-CRE terminal that feeds back the CQI measured at the transmission timing of the normal subframe when the resource block ratio is equal to or greater than the predetermined threshold. A channel quality feedback radio resource allocating unit 660 for generating index allocation information for the CRE terminal so as to generate index allocation information and feed back CQI measured at the ABS transmission timing; The index allocation information generated by the radio resource allocation unit 660 is A downlink channel information allocation unit 670 that transmits to a radio terminal communicating with the pico base station 300.

  With this configuration, wireless terminals are grouped based on the resource block ratio, and the non-CRE terminal feeds back only the CQI measured at the transmission timing of the normal subframe, and only the CQI measured at the ABS transmission timing. The CRE terminal feeds back. Therefore, the channel quality index of the number of reports controlled for each group is fed back from the radio terminals grouped according to the ratio of radio resources. Thereby, even when the user terminal (wireless terminal) periodically feeds back the channel quality index for each subframe type to the pico base station, the wireless communication device does not deteriorate the throughput performance of the physical uplink shared channel (PUSCH). Can be.

Also, the grouping unit 650 groups the wireless terminals according to the ratio of the number of subframes in a predetermined unit of normal subframes and ABS (for example, 40 subframes) and the number of subframes X of ABS. Turn into.
With this configuration, the channel quality index of the number of reports controlled for each group is fed back from the wireless terminals grouped according to the ratio of the number of subframes. Thereby, even when the user terminal (wireless terminal) periodically feeds back the channel quality index for each subframe type to the pico base station, the wireless communication device does not deteriorate the throughput performance of the physical uplink shared channel (PUSCH). Can be.

Also, the grouping unit 650 groups the wireless terminals based on the downlink channel reception strength (for example, RSRP) or the signal-to-interference noise power ratio (SINR, RSRQ).
With this configuration, the channel quality index of the number of reports controlled for each group is fed back from the wireless terminals grouped based on the reception strength of the downlink channel or the signal-to-interference noise power ratio. Thereby, even when the user terminal (wireless terminal) periodically feeds back the channel quality index for each subframe type to the pico base station, the wireless communication device does not deteriorate the throughput performance of the physical uplink shared channel (PUSCH). Can be.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

  For example, the reception intensity of the reference signal may be a signal-to-interference noise power ratio of the reference signal (eg, Signal-to-Interference and Noise power Ratio (SINR), Reference Signal Received Quality (RSRQ)). In this case, the grouping unit 650 may select wireless terminals whose signal-to-interference noise power ratio difference is equal to or greater than a threshold F (for example, 5 [dB]).

  Also, for example, the queue length of the buffer that stores data transmitted to some non-CRE terminals is the same as the queue length (for example, 1 [Mbyte]) of the buffer that stores data transmitted to the CRE terminal. Fine adjustments may be made so that When the queue length is finely adjusted, radio communication apparatus 600 can transmit data to some non-CRE terminals at a higher speed than other non-CRE terminals.

DESCRIPTION OF SYMBOLS 100 ... Macro base station, 200 ... Macro cell, 300 ... Pico base station, 400 ... Pico cell, 410 ... Extended pico cell, 500 ... CRE terminal, 600 ... Wireless communication apparatus, 610 ... Pattern acquisition part, 620 ... Terminal information acquisition part, 630 ... Uplink channel information allocation unit, 640 ... Ratio calculation unit, 650 ... Grouping unit, 660 ... Radio resource allocation unit for channel quality feedback, 670 ... Downlink channel information allocation unit

Claims (4)

A macro base station that transmits a first type subframe in which data transmission is not restricted and a second type subframe in which data transmission is restricted at mutually exclusive transmission timings, the first type subframe, and the In a heterogeneous network comprising a non-macro base station having a downlink channel that receives interference from a second type subframe,
A ratio calculation unit that calculates a ratio of radio resources of the uplink channel to which shared channel data other than the channel quality index of the downlink channel is allocated to all radio resources in a predetermined unit of the uplink channel of the non-macro base station;
When the ratio is equal to or greater than a predetermined threshold, a first group that transmits the channel quality indicator measured at a timing at which the first type subframe is transmitted, and a timing at which the second type subframe is transmitted. A second group for transmitting the channel quality indicator measured to a grouping unit for grouping the wireless terminals;
When the ratio is equal to or greater than the predetermined threshold, index assignment information is generated for wireless terminals belonging to the first group so as to feed back the channel quality indicator measured at the transmission timing of the first type subframe. And a channel quality feedback radio resource allocation unit that generates index allocation information for radio terminals belonging to the second group so as to feed back the channel quality index measured at the transmission timing of the second type subframe. When,
A downlink channel information allocation unit that transmits the index allocation information generated by the channel quality feedback radio resource allocation unit to a radio terminal that communicates with the non-macro base station;
A wireless communication apparatus comprising:   The grouping unit includes the wireless terminal according to a ratio of the number of all subframes in a predetermined unit of the first type subframe and the second type subframe to the number of subframes of the second type subframe. The wireless communication device according to claim 1, wherein the wireless communication devices are grouped.   The radio communication apparatus according to claim 1 or 2, wherein the grouping unit groups the radio terminals based on a reception intensity or a signal-to-interference noise power ratio of the downlink channel. A macro base station that transmits a first type subframe in which data transmission is not restricted and a second type subframe in which data transmission is restricted at mutually exclusive transmission timings, the first type subframe, and the A non-macro base station having a downlink channel that receives interference from the second type subframe, and a computer of a wireless communication device in a heterogeneous network,
A step of calculating a ratio of radio resources of the uplink channel to which shared channel data other than the channel quality index of the downlink channel is allocated to all radio resources of a predetermined unit of the uplink channel of the non-macro base station;
When the ratio is equal to or greater than a predetermined threshold, a first group that transmits the channel quality indicator measured at a timing at which the first type subframe is transmitted, and a timing at which the second type subframe is transmitted. A second group for transmitting the measured channel quality indicator to a group, and a procedure for grouping the wireless terminals into
If the ratio is equal to or greater than a predetermined threshold, generating index allocation information for the wireless terminals belonging to the first group so as to feed back the channel quality index measured at the transmission timing of the first type subframe, And a procedure for generating index allocation information for the wireless terminals belonging to the second group so as to feed back the channel quality index measured at the transmission timing of the second type subframe,
Transmitting the generated index allocation information to a wireless terminal communicating with the non-macro base station;
Wireless communication program for executing

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