JP2013201575A - Communication control apparatus, communication control method, and communication control program - Google Patents

Abstract

A communication control apparatus, a communication control method, and a communication control program capable of appropriately operating an OLLA according to interference conditions in HetNet or the like are provided.
A communication control apparatus (for example, a function of a base station 1) includes an interference measurement unit 15 that measures dispersion or standard deviation of interference power based on a signal from a mobile station, and a signal from the mobile station. When an error is not detected after demodulation, an ACK is output, while a NACK is output when an error is detected, and a variance of the interference power measured by the interference measurement unit 15 Alternatively, based on the standard deviation and the ACK or NACK output from the demodulator 16, an SINR offset calculator 17 that calculates an SINR offset value, and at least an SINR offset value calculated by the SINR offset calculator 17 And an MCS determination unit 18 for determining the MCS based on the above.
[Selection] Figure 1

Description

  The present invention relates to a communication control device, a communication control method, and a communication control program.

Conventionally, LTE (Long Term Evolution) is known as one of the standards studied by 3GPP (Third Generation Partnership Project). LTE is being revised sequentially.
In LTE, as a measure for improving cell throughput, one or more pico base stations, which are narrow base stations, are arranged in the area of a macro base station, which is a base station (base station device) having a wide coverage, and heterogeneous. The introduction of a network (HetNet: Heterogeneous Network) is being studied and specified.

FIG. 2 is a block diagram showing a schematic configuration of a mobile radio communication system to which HetNet is applied.
The mobile radio communication system according to this example includes a macro base station 101, pico base stations 111 and 112, and mobile stations (mobile station devices) 121 to 123.
2 shows a communication area 201 of the macro base station 101, a communication area 211 of the pico base station 111, and a communication area 212 of the pico base station 112.

Here, in the example of FIG. 2, two pico base stations 111 and 112 are provided in the communication area 201 of the macro base station 101, and the communication areas 211 of these two pico base stations 111 and 112 are provided. , 212 are included.
In the example of FIG. 2, a plurality of (three in the example of FIG. 2) mobile stations 121 to 123 exist in the communication area 201 of the macro base station 101. Then, the mobile station 121 performs wireless communication with the macro base station 101, and the mobile station 122 exists within the communication area 211 of the pico base station 111 and performs wireless communication with the pico base station 111. The mobile station 123 exists in the communication area 212 of the pico base station 112 and performs radio communication with the pico base station 112.

  Here, the link in the direction from the mobile station 121 to 123 to the base station (macro base station 101, pico base station 111, 112) is an uplink, and the base station (macro base station 101, pico base station 111, 112). The links in the direction from mobile stations 121 to 123 are downlinks.

  When the pico base station and the macro base station use the same frequency in the uplink of HetNet, the pico base stations 111 and 112 receive strong interference from the signal transmitted by the mobile station 121 communicating with the macro base station 101. There is a problem. In particular, the interference power observed at the pico base stations 111 and 112 has a large variance, making it difficult to select a modulation scheme and coding scheme (MCS) according to the channel conditions. There's a problem.

As a technique for solving such a problem that MCS cannot be optimally designated, for example, as described in Non-Patent Document 1, it is effective to use OLLA (Outer Loop Link Adaptation) (for example, Non-patent document 1).
In the normal MCS determination process, the base station calculates the SINR (Signal to Interference plus Noise Ratio) in the frequency / time domain assigned to the mobile station, and selects an MCS that satisfies the target BLER (Block Error Rate). .
Here, the unit of frequency / time domain allocation that the base station allocates to the mobile station is referred to as RB (Resource Block).

OLLA is a technique for calculating MCS by adding an offset value calculated according to whether or not a mobile station can transmit a signal in the past (ACK / NACK) to SINR.
Specifically, in the case where ACK frequently occurs, it operates to select a high MCS by adding a positive offset value to the calculated SINR, and conversely, NACK frequently occurs. In such a case, a negative offset value is added to the calculated SINR to operate so as to select a low MCS. As a specific example of the operation, Equations (1-1) and ( The process represented by 1-2) is performed.

In Expression (1-1) and Expression (1-2), when it is ACK, the calculation shown in Expression (1-1) is performed, and when it is NACK, it is shown in Expression (1-2). An operation is performed.
Here, in Expression (1-1) and Expression (1-2), the SINR _{offset on} the left side represents a value after calculation (after change), and the SINR _{offset on} the right side represents a current value before calculation (before change). Represent.

In Expression (1-1) and Expression (1-2), SINR _offset is an offset value used to obtain SINR used when selecting MCS. And MCS is determined using the value (SINR _measured + SINR _offset ) of the result of adding SINR _measured and SINR _offset which are _measured SINRs.
In Expressions (1-1) and (1-2), StepSize is an OLLA parameter, and BLER _target is a target BLER.
In the formula (1-1), “*” represents multiplication.

  Here, relatively, if StepSize is set to a large value, it becomes easier to follow when the estimated SINR error level fluctuates sharply, whereas if StepSize is set to a small value, the estimated SINR error is set. The MCS can be set correctly when the level is fixed.

A. Pokkariyal, K .; I. Pedersen, G.M. Monghal, I .; Z. Kovacs, C.I. Rosa, T .; E. Kolding, and P.K. E. Mogensen, "HARQ Aware Frequency Domain Packet Scheduler with Different Degrees of Fairness for the UTRAN Long Term Evolution", in Proceedings of the IEEE Vehicular Technology Conference (VTC'S07), April 2007.

However, when the OLLA technology as described in Non-Patent Document 1 is applied to the uplink of HetNet, there are some problems.
The first problem is that the magnitude of interference largely varies (changes) in the time and frequency domains in the uplink of HetNet. Since OLLA is a control method that reaches an optimum SINR offset value over a certain period of time, in situations where the interference level fluctuates violently in units of RBs, it is not possible to achieve the target BLER. It operates to select a necessary high offset value (ie, a value of MCS that is too low). For this reason, the problem that a throughput falls arises.

The second problem is that interference fluctuations are not always constant. That is, when traffic such as an FTP model is assumed, depending on the uplink communication status of the macro base station serving as an environment, the interference power may be stabilized, or a situation in which it rapidly changes in units of RBs may occur.
For the above reasons, there has been a problem that OLLA may not operate properly in the uplink of HetNet.

  The present invention has been made in view of such circumstances, and provides a communication control device, a communication control method, and a communication control program capable of appropriately operating an OLLA in accordance with interference conditions in a HetNet or the like. Is an issue.

  (1) In order to solve the above-described problem, a communication control apparatus according to the present invention includes an interference measurement unit that measures dispersion or standard deviation of interference power based on a signal from a mobile station, and a signal from the mobile station. And when the error is not detected, an ACK is output, while when an error is detected, a demodulation unit that outputs NACK and a dispersion of the interference power measured by the interference measurement unit or Based on a standard deviation and an SINR offset calculation unit that calculates an SINR offset value based on the ACK or NACK output from the demodulation unit, and at least an SINR offset value calculated by the SINR offset calculation unit, An MCS determination unit for determining the MCS.

  (2) In the communication control device according to (1), the present invention further includes a channel measurement unit that measures a channel based on a signal from the mobile station and measures a signal power, and the channel measurement unit. A scheduling unit that allocates resources based on the measured channel information, wherein the interference measurement unit measures average interference power based on a signal from the mobile station and distributes the interference power Alternatively, the standard deviation is measured, and the MCS determination unit is configured to determine the signal power measured by the channel measurement unit, the average interference power measured by the interference measurement unit, and the SINR calculated by the SINR offset calculation unit. The MCS is determined based on the offset value.

  (3) In the communication control device according to (1) or (2) described above, the SINR offset calculation unit is configured so that the interference measurement unit outputs the ACK when the ACK is output from the demodulation unit. When the dispersion or standard deviation of the measured interference power is large, a large SINR offset value is calculated. On the other hand, when the dispersion or standard deviation of the interference power is small, a small SINR offset value is calculated, and the SINR is calculated. The offset calculation unit calculates a small SINR offset value when a dispersion or standard deviation of the interference power measured by the interference measurement unit is large when a NACK is output from the demodulation unit. When the power dispersion or the standard deviation is small, a large SINR offset value is calculated.

  (4) In the communication control device according to any one of (1) to (3) described above, the SINR offset calculation unit may include the interference power measured by the interference measurement unit. The SINR offset value is calculated using an equation that includes variance or standard deviation as a parameter, and the absolute value of the step size term increases as the variance or standard deviation of the interference power increases.

  (5) In the communication control device according to any one of (1) to (3) described above, the SINR offset calculation unit may include the interference power measured by the interference measurement unit. The step size is set so that the absolute value of the step size is larger when the variance or standard deviation is larger than the predetermined threshold value than when the variance or standard deviation is less than or equal to the threshold value, and an expression including the step size as a parameter And an SINR offset value is calculated.

  (6) In order to solve the above-described problem, in the communication control method according to the present invention, the interference measurement unit measures the dispersion or standard deviation of the interference power based on the signal from the mobile station, and the demodulation unit When the signal from the mobile station is demodulated and an error is not detected, an ACK is output. On the other hand, when an error is detected, an NACK is output, and the SINR offset calculation unit is measured by the interference measurement unit. An SINR offset value is calculated based on the dispersion or standard deviation of the interference power and the ACK or NACK output from the demodulation unit, and the MCS determination unit is calculated by at least the SINR offset calculation unit The MCS is determined based on the SINR offset value.

  (7) In order to solve the above-described problem, a communication control program according to the present invention includes a step in which an interference measurement unit measures dispersion or standard deviation of interference power based on a signal from a mobile station, and a demodulation unit Demodulating the signal from the mobile station and outputting an ACK if an error is not detected, while outputting an NACK if an error is detected, and an SINR offset calculation unit includes the interference A step of calculating an SINR offset value based on the dispersion or standard deviation of the interference power measured by the measuring unit and the ACK or NACK output from the demodulating unit; and the MCS determining unit includes at least the SINR offset A step of determining the MCS based on the SINR offset value calculated by the calculation unit; A gram.

  According to the present invention, OLLA can be appropriately operated in HetNet or the like according to the state of interference.

It is a block diagram which shows the schematic structure of the base station apparatus which concerns on one Embodiment of this invention. It is a block diagram which shows the schematic structure of the mobile radio | wireless communications system to which HetNet is applied.

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

[First Embodiment]
In the present embodiment, a mobile radio communication system to which HetNet as shown in FIG. 2 is applied is assumed.
Further, in the present embodiment, an uplink transmitting a signal from a mobile station (UE) to a base station (eNB) is assumed, and further, as an access scheme, OFDMA (Orthogonal Frequency Division Multiplexing) that performs allocation in the frequency domain. Access) or SC-FDMA (Single Carrier-Frequency Division Multiple Access).

FIG. 1 is a block diagram showing a schematic configuration of a base station (base station apparatus) 1 according to an embodiment of the present invention.
The base station 1 according to the present embodiment is applied to a pico base station (for example, the pico base stations 111 and 112 illustrated in FIG. 2), but other base stations (for example, the macro base station 101 illustrated in FIG. 2). ) May be applied.

  The base station 1 according to the present embodiment includes an antenna 11, a radio reception unit 12, a channel measurement unit 13, a scheduling unit 14, an interference measurement unit 15, a demodulation unit 16, a SINR offset calculation unit 17, and an MCS. A determination unit 18, a control signal generation unit 19, a downlink signal generation unit 20, and a radio transmission unit 21 are provided.

An example of operations performed in the base station 1 according to the present embodiment will be shown.
An uplink signal transmitted from the mobile station by radio is received by the antenna 11 and input to the radio reception unit 12.
The radio reception unit 12 performs down-conversion, FFT (Fast Fourier Transform) processing, and the like on the signal (reception signal) input from the antenna 11 and performs classification according to the type of the uplink signal. Are output to the channel measurement unit 13, the interference measurement unit 15, and the demodulation unit 16.

The signal output from the wireless reception unit 12 to the channel measurement unit 13 is mainly a reference signal for channel measurement.
The channel measurement unit 13 calculates reception power for each frequency domain (for example, for each successive RB) based on a signal (for example, a reference signal for channel measurement) input from the wireless reception unit 12, and the result ( Channel status information) is output to the scheduling unit 14.
The scheduling unit 14 performs frequency scheduling according to the state of the channel specified by the information input from the channel measurement unit 13 (for example, including received power), and performs RB allocation for each mobile station. Then, the scheduling unit 14 outputs information on the result of RB allocation and information on the calculated signal power (for example, received power) to the MCS determination unit 18.

A signal output from the wireless reception unit 12 to the interference measurement unit 15 is mainly a reference signal for demodulation.
The interference measurement unit 15 measures interference using a demodulation reference signal among the output signals from the wireless reception unit 12.
Here, the interference calculated by the interference measuring unit 15 is an average interference power averaged in the system frequency band and a specific time range.
Furthermore, the interference measurement unit 15 calculates interference power for each frequency domain (for example, for each of a plurality of consecutive RBs), and calculates the variance. Note that the calculation of the variance may be performed, for example, in one processing time (1 ms in the case of LTE), or may be performed in a plurality of processing times.
The interference measurement unit 15 outputs the calculated average interference power information to the MCS determination unit 18, and outputs the calculated interference power dispersion information to the SINR offset calculation unit 17.

The signal output from the wireless receiving unit 12 to the demodulating unit 16 is mainly a data channel signal.
The demodulator 16 performs demodulation and error detection of the data channel signal transmitted from the mobile station based on the signal input from the radio receiver 12. Then, the demodulator 16 outputs the demodulated data and ACK or NACK information indicating whether or not an error is detected in the data to the upper layer. The ACK or NACK information is also output to the SINR offset calculation unit 17.
Here, ACK is output when no error is detected in the data, and NACK is output when an error is detected in the data.

The SINR offset calculation unit 17 inputs the interference power dispersion information output from the interference measurement unit 15 and the ACK or NACK information output from the demodulation unit 16, and sets the SINR offset value SINR _offset based on the OLLA. calculate. Then, the SINR offset calculation unit 17 outputs the calculated SINR offset value SINR _offset to the MCS determination unit 18.

Here, examples (first example to fourth example) that can be applied to the procedure of determining the SINR _offset value SINR _offset in the SINR offset calculation unit 17 will be shown. Note that the variance of the interference power is σ ² .

<First Example of Procedure for Determining SINR Offset Value> is expressed by Expression (2-1) and Expression (2-2).
In Expressions (2-1) and (2-2), when ACK information is input to the SINR offset calculation unit 17, the calculation shown in Expression (2-1) is performed, and the SINR offset calculation unit 17 When the NACK information is input to, the calculation shown in Expression (2-2) is performed.
Here, in Equations (2-1) and (2-2), the SINR _{offset on} the left side represents the value after the calculation (after change), and the SINR _{offset on} the right side represents the value before the calculation (before change). Represent.

In Expression (2-1) and Expression (2-2), SINR _offset is an offset value used for obtaining SINR used when selecting MCS. And MCS is determined using the value (SINR _measured + SINR _offset ) of the result of adding SINR _measured and SINR _offset which are _measured SINRs.
In Expressions (2-1) and (2-2), StepSize is an OLLA parameter, and BLER _target is a target BLER.
In the formulas (2-1) and (2-2), “*” and “•” represent multiplication.

Here, in the formula (2-1) and the formula (2-2), with respect to the formula (1-1) and the formula (1-2), an arithmetic expression obtained by multiplying StepSize by the interference power variance σ ² It has become.

<Second Example of Procedure for Determining SINR Offset Value> is expressed by Expression (3-1) and Expression (3-2).
Equation (3-1) and the equation (3-2), with respect to formula (2-1) and (2-2), the formula (2-1) and (sigma ² · in formula (2-2) The portion of (StepSize) is replaced with (α · σ ² + StepSize).
Here, in Expressions (3-1) and (3-2), α is a coefficient applied to the interference power variance σ ² , and is a positive value, for example, and various values are set. May be.

<Third example of procedure for determining SINR offset value> is the same as the above-described <First example of procedure for determining SINR offset value> in Equations (2-1) and (2-2). The standard deviation σ of interference power is used instead of the variance σ ² of interference power.
In this case, the standard deviation σ of the interference power may be calculated by the interference measurement unit 15 and output to the SINR offset calculation unit 17, or may be calculated by the SINR offset calculation unit 17, for example.

<Fourth example of procedure for determining SINR offset value> is the same as the above-described <second example of procedure for determining SINR offset value> in Equations (3-1) and (3-2) The standard deviation σ of interference power is used instead of the variance σ ² of interference power.
In this case, the standard deviation σ of the interference power may be calculated by the interference measurement unit 15 and output to the SINR offset calculation unit 17, or may be calculated by the SINR offset calculation unit 17, for example.

Here, in the above-described <first example of procedure for determining SINR offset value> to <fourth example of procedure for determining SINR offset value>, interference power variance σ ² (or interference power When the standard deviation σ) is large, the step size (StepSize) term is set large, and when the interference power variance σ ² (or the interference power standard deviation σ) is small, the step size (StepSize) term is set small. It is to be. This makes it possible to operate the OLLA so as to follow the fluctuation of the interference when it is severe, and when the fluctuation of the interference is small, the control by the OLLA is gently performed so as to be adjusted to the optimum MCS. Can be implemented.

The MCS determination unit 18 outputs the RB allocation result information and signal power information output from the scheduling unit 14, the average interference power information output from the interference measurement unit 15, and the SINR offset calculation unit 17. SINR offset value SINR _offset information is input, and an MCS to be applied to an uplink signal transmitted from the mobile station is determined. Then, the MCS determination unit 18 outputs the determined MCS information to the control signal generation unit 19.

In the present embodiment, the base station 1 holds (stores) information of a correspondence table between SINR and MCS that achieves a target BLER in a storage unit (for example, a memory) such as the MCS determination unit 18. Then, the MCS determination unit 18 calculates SINR _ref , which is an SINR for referring to the MCS, using Expression (4), and determines the MCS corresponding to the calculated SINR _ref based on the correspondence table.

  Here, in Expression (4), for example, the noise power may be calculated or detected by an arbitrary method, or may be set in advance to a fixed value or the like.

The control signal generation unit 19 generates a control signal instructing the mobile station to perform uplink transmission based on the MCS information input from the MCS determination unit 18, and transmits the generated control signal to the downlink signal generation unit. 20 is output.
This control signal includes MCS information calculated (determined) by the MCS determination unit 18. System

The downlink signal generation unit 20 receives a control signal from the control signal generation unit 19 and also receives other downlink signals (downlink transmission data), and generates and generates a downlink signal based on these signals. The downlink signal is output to the wireless transmission unit 21.
The radio transmission unit 21 performs processing such as modulation and up-conversion on the downlink signal input from the downlink signal generation unit 20, and then outputs a signal resulting from the processing to the antenna 11.
This signal is transmitted wirelessly to the mobile station via the antenna 11.

  As described above, in the mobile radio communication system according to the present embodiment, the uplink signal transmitted from the mobile station is received in the base station 1 that receives the uplink signal transmitted from the mobile station and determines the MCS of the uplink signal. A channel measurement unit 13 that measures a channel from a link signal and measures signal power, a scheduling unit 14 that allocates resources using the measured channel information, and an average from uplink signals transmitted from mobile stations An interference measurement unit 15 that measures interference power and interference power dispersion (or standard deviation), and an uplink signal transmitted from a mobile station is demodulated, and if it is received correctly, an ACK is output and an error is detected. If so, the demodulator 16 that outputs NACK, the dispersion (or standard deviation) of the interference power described above, the ACK or NACK described above Comprising the SINR offset calculation unit 17 for calculating an offset value of SINR according, the MCS determination portion 18 that determines the MCS using the offset value of the SINR obtained by the the average interference power that the said signal power, the.

Further, in the base station 1 in the mobile radio communication system according to the present embodiment, the SINR offset calculation unit 17 has a large SINR offset when the dispersion (or standard deviation) of the interference power is large at the time of ACK. While calculating and outputting a value, when the dispersion (or standard deviation) of the interference power is small, a small SINR offset value is calculated and output.
On the contrary, in the base station 1 in the mobile radio communication system according to the present embodiment, the SINR offset calculation unit 17 has a small SINR when the dispersion (or standard deviation) of the interference power described above is large at the time of NACK. While calculating and outputting the offset value, when the variance (or standard deviation) of the interference power described above is small, a large SINR offset value is calculated and output.

According to the base station 1 in the mobile radio communication system according to the present embodiment, for example, even when the magnitude of interference largely varies (changes) in the time and frequency domains as in the uplink in HetNet, it is more appropriate for OLLA. Therefore, the problem that an unnecessarily low MCS is set can be alleviated.
Further, according to the base station 1 in the mobile radio communication system according to the present embodiment, for example, even when a case where the interference power is stabilized in the uplink of the HetNet occurs due to traffic such as an FTP model, it is moderated by OLLA. MCS can be adjusted to improve the throughput.

  As described above, in the base station 1 in the mobile radio communication system according to the present embodiment, the optimization of the OLLA parameters in accordance with the interference situation is performed by the uplink link adaptation according to the interference amount (for example, automatically). As a result, throughput can be improved. Thereby, OLLA can be appropriately operated according to the interference situation in HetNet or the like.

[Second Embodiment]
The mobile radio communication system according to the present embodiment is roughly the same as that shown in FIG.
Moreover, the schematic structure of the base station apparatus 1 which concerns on this embodiment is the same as that shown by FIG. 1 which concerns on 1st Embodiment.
For this reason, in this embodiment, it demonstrates using the same code | symbol as what is shown by FIG.

Compared with the operation performed in the base station apparatus 1 according to the first embodiment, the operation performed in the base station apparatus 1 according to the present embodiment is a method in which the SINR offset calculation unit 17 calculates the SINR offset value SINR _offset. The same except for the differences.
In the following, differences from the case of the first embodiment will be mainly described.

As a different point from the case of the first embodiment, an example (fifth example) that can be applied to the procedure of determining the SINR _offset value SINR _offset in the SINR offset calculation unit 17 is shown. Note that the variance of the interference power is σ ² .

<Fifth Example of Procedure for Determining SINR Offset Value> is expressed by Expression (5-1) and Expression (5-2), Expression (6-1), and Expression (6-2).
In the expressions (5-1) and (5-2), when the interference power variance σ ² is larger than a predetermined threshold Threshold, as shown in the expression (5-1), StepSize = a and On the other hand, when the variance σ ^{2 of the} interference power is equal to or smaller than the predetermined threshold Threshold, StepSize = b is set as shown in Expression (5-2).

Here, the threshold Threshold is a threshold for switching the value of StepSize according to the magnitude of the interference power variance σ ² .
Various values may be used as the threshold Threshold.
By performing control using such a threshold value, the calculation of the SINR offset value can be simplified.

For example, a and b are positive values, and the value of a is larger than the value of b (that is, a> b).
For example, a configuration in which b is 0 can also be used. That is, in the case where the throughput deteriorates by using OLLA, the function of OLLA can be substantially disabled by setting Stepsize = 0.
Moreover, it is not restricted to the value of a and b in this embodiment, Even if a and b are each arbitrary values, Formula (5-1), Formula (5-2), and Formula (6-1) And Equation (6-2) holds. Furthermore, in the present procedure, it has been described that two conditions are given according to the magnitude of the variance, but it is also possible to calculate the SINR _offset value SINR _offset by giving three or more conditions.

In Expressions (6-1) and (6-2), when ACK information is input to the SINR offset calculation unit 17, the calculation shown in Expression (6-1) is performed, and the SINR offset calculation unit 17 When the NACK information is input to, the calculation shown in Expression (6-2) is performed.
Here, in Equations (6-1) and (6-2), the SINR _{offset on} the left side represents the value after the calculation (after change), and the SINR _{offset on} the right side represents the current value before the calculation (before change). Represent.

In Expressions (6-1) and (6-2), SINR _offset is an offset value used for obtaining SINR used when selecting MCS. And MCS is determined using the value (SINR _measured + SINR _offset ) of the result of adding SINR _measured and SINR _offset which are _measured SINRs.
In Expressions (6-1) and (6-2), StepSize is an OLLA parameter, and BLER _target is a target BLER.
In the formulas (6-1) and (6-2), “*” represents multiplication.

As described above, the base station 1 in the mobile radio communication system according to the present embodiment can roughly obtain the same effects as those of the first embodiment.
Further, in the base station 1 in the mobile radio communication system according to the present embodiment, the SINR offset value is obtained by performing control using a threshold value as shown in Equations (5-1) and (5-2). Calculation can be simplified.

[Configuration example according to the above embodiment]
The structural example which concerns on the above embodiment is shown.
The base station 1 according to the above embodiment has the function of a communication control device as shown below.
(Configuration example 1: refer to FIG. 1) An interference measurement unit 15 that measures dispersion (or standard deviation) of interference power based on a signal from a mobile station, and a signal from the mobile station is demodulated to eliminate errors. If it is a detection (that is, if it is not detected), an ACK is output, while if an error is detected, a demodulation unit 16 that outputs a NACK and the interference measured by the interference measurement unit 15 Based on power distribution (or standard deviation) and the ACK or NACK output from the demodulator 16, an SINR offset calculator 17 that calculates an SINR offset value, and at least calculated by the SINR offset calculator 17 And a MCS determination unit 18 that determines an MCS based on the SINR offset value.
Here, since the variance and the standard deviation correspond on a one-to-one basis, an arbitrary one (one of the variance or the standard deviation) may be used at an arbitrary place.

  (Configuration example 2: see FIG. 1, equation (4)) Further, the channel measurement unit 13 measures the channel based on the signal from the mobile station and measures the signal power, and the channel measurement unit 13 measures the channel power. And a scheduling unit for allocating resources based on the information on the channel, and the interference measuring unit 15 measures the average interference power based on the signal from the mobile station and distributes the interference power. (Or standard deviation) is measured, and the MCS determination unit 18 calculates the signal power measured by the channel measurement unit 13, the average interference power measured by the interference measurement unit 15, and the SINR offset calculation. The MCS is determined based on the SINR offset value calculated by the unit 17, and the communication control according to (Configuration Example 1) is characterized. Apparatus, it is.

  (Structure Example 3: Formula (2-1) to Formula (2-2), Formula (3-1) to Formula (3-2), Formula (5-1) to Formula (5-2), Formula (6 -1) to Equation (6-2)) The SINR offset calculation unit 17 distributes the interference power measured by the interference measurement unit 15 when an ACK is output from the demodulation unit 16 (or When the standard deviation) is large, a large SINR offset value is calculated. On the other hand, when the variance (or standard deviation) of the interference power is small, a small SINR offset value is calculated. When the NACK is output from the demodulator 16 and the variance (or standard deviation) of the interference power measured by the interference measurement unit 15 is large, a small SINR offset value is calculated. Dispersion of the interference power Or to calculate the offset value of the large SINR if the standard deviation) is small, it is, the communication control device having the constitution (Configuration Example 1) or (Configuration Example 2).

(Refer to Configuration Example 4: Expression (2-1) to Expression (2-2), Expression (3-1) to Expression (3-2)) The SINR offset calculation unit 17 is measured by the interference measurement unit 15. The interference power variance (or standard deviation) is included as a parameter, and the larger the variance (or standard deviation) of the interference power is, the larger the absolute value of the step size (StepSize) term is. The communication control device according to any one of (Configuration Example 1) to (Configuration Example 3), wherein an SINR offset value is calculated.
Here, in the formulas (2-1) to (2-2), the step size (StepSize) is (σ ₂ · StepSize).
Further, in the expressions (3-1) to (3-2), the term of the step size (StepSize) is (α · σ ₂ + StepSize).

(Refer to Configuration Example 5: Formula (5-1) to Formula (5-2), Formula (6-1) to Formula (6-2)) The SINR offset calculation unit 17 is measured by the interference measurement unit 15. The step size is set so that the absolute value of the step size (StepSize) is larger when the variance (or standard deviation) of the interference power is larger than a predetermined threshold value than when the variance is smaller than the threshold value. The communication control apparatus according to any one of (Configuration Example 1) to (Configuration Example 3), characterized in that an SINR offset value is calculated using an equation including the step size as a parameter. .
Here, in formulas (5-1) to (5-2), Threshold is used as the above-described threshold.

[Summary of the above embodiments]
As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.

  Further, a program for realizing the function of each device according to the embodiment described above (for example, the function of the base station (base station device) 1 or the like) is recorded on a computer-readable recording medium, and this recording medium Processing may be performed by causing the computer system to read and execute the program recorded in the above.

The “computer system” mentioned here may include an operating system (OS) and hardware such as peripheral devices.
The “computer-readable recording medium” means a flexible disk, a magneto-optical disk, a ROM (Read Only Memory), a writable nonvolatile memory such as a flash memory, a portable medium such as a DVD (Digital Versatile Disk), A storage device such as a hard disk built in a computer system.

Further, the “computer-readable recording medium” refers to a volatile memory (for example, DRAM (DRAM) inside a computer system that becomes a server or a client when a program is transmitted through a network such as the Internet or a communication line such as a telephone line. Dynamic Random Access Memory)) that holds a program for a certain period of time is also included.
The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting a program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.
Further, the above program may be for realizing a part of the functions described above.
Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

DESCRIPTION OF SYMBOLS 1 ... Base station (base station apparatus) 11 ... Antenna, 12 ... Radio | wireless receiving part, 13 ... Channel measurement part, 14 ... Scheduling part, 15 ... Interference measurement part, 16 ... Demodulation part, 17 ... SINR offset calculation part, 18 DESCRIPTION OF SYMBOLS ... MCS determination part, 19 ... Control signal generation part, 20 ... Downlink signal generation part, 21 ... Radio transmission part, 101 ... Macro base station, 111, 112 ... Pico base station, 121-123 ... Mobile station (mobile station apparatus) ), 201, 211, 212 ... communication area

Claims (7)

An interference measurement unit that measures dispersion or standard deviation of interference power based on a signal from a mobile station;
A demodulator that demodulates the signal from the mobile station and outputs an ACK if an error is not detected, and outputs a NACK if an error is detected;
A SINR offset calculation unit that calculates an SINR offset value based on the dispersion or standard deviation of the interference power measured by the interference measurement unit and the ACK or NACK output from the demodulation unit;
An MCS determination unit that determines an MCS based on at least an SINR offset value calculated by the SINR offset calculation unit;
A communication control apparatus comprising: A channel measuring unit for measuring a channel based on a signal from the mobile station and measuring a signal power;
A scheduling unit that allocates resources based on channel information measured by the channel measurement unit,
The interference measurement unit measures an average interference power based on a signal from the mobile station, and measures a dispersion or standard deviation of the interference power,
The MCS determination unit, based on the signal power measured by the channel measurement unit, the average interference power measured by the interference measurement unit, and the SINR offset value calculated by the SINR offset calculation unit, Determine MCS,
The communication control apparatus according to claim 1. The SINR offset calculating unit calculates a large SINR offset value when a dispersion or standard deviation of the interference power measured by the interference measuring unit is large when ACK is output from the demodulating unit, If the variance or standard deviation of the interference power is small, calculate a small SINR offset value,
The SINR offset calculation unit calculates a small SINR offset value when a dispersion or standard deviation of the interference power measured by the interference measurement unit is large when NACK is output from the demodulation unit, When the variance or standard deviation of the interference power is small, a large SINR offset value is calculated.
The communication control apparatus according to claim 1 or claim 2, wherein The SINR offset calculation unit includes a dispersion or standard deviation of the interference power measured by the interference measurement unit as a parameter, and an absolute value of a step size term increases as the interference power dispersion or standard deviation increases. Is used to calculate the SINR offset value,
The communication control apparatus according to any one of claims 1 to 3, wherein the communication control apparatus is configured as described above. The SINR offset calculation unit has a larger absolute value of the step size when the variance or standard deviation of the interference power measured by the interference measurement unit is larger than a predetermined threshold value than when the interference size is less than or equal to the threshold value. The step size is set so that the offset value of SINR is calculated using an equation including the step size as a parameter.
The communication control apparatus according to any one of claims 1 to 3, wherein the communication control apparatus is configured as described above. The interference measurement unit measures the dispersion or standard deviation of the interference power based on the signal from the mobile station,
The demodulator demodulates the signal from the mobile station and outputs an ACK if an error is not detected, while outputting an NACK if an error is detected,
A SINR offset calculation unit calculates a SINR offset value based on the dispersion or standard deviation of the interference power measured by the interference measurement unit and the ACK or NACK output from the demodulation unit;
The MCS determination unit determines the MCS based on at least the SINR offset value calculated by the SINR offset calculation unit;
A communication control method characterized by the above. An interference measurement unit measuring dispersion or standard deviation of interference power based on a signal from a mobile station;
A demodulator that demodulates the signal from the mobile station and outputs an ACK if an error is not detected, while outputting an NACK if an error is detected;
A SINR offset calculation unit calculating a SINR offset value based on the dispersion or standard deviation of the interference power measured by the interference measurement unit and the ACK or NACK output from the demodulation unit;
An MCS determination unit determining an MCS based on at least an SINR offset value calculated by the SINR offset calculation unit;
Communication control program for causing a computer to execute.

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