JP2015065655A - Method, terminal, and system, for reference signal reception power determination - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method, terminal, and system for determining reference signal reception power.SOLUTION: A method includes: a step for generating two specific cell reference signals corresponding to a measurement cell and an interfering cell, respectively; a step for performing channel estimation for a signal on each one of neighboring resource elements having a reference signal in a resource block, for each of at least one resource block of the measurement cell, and acquiring a channel estimation result corresponding to each of the neighboring resource elements; a step for pairing neighboring resource elements and acquiring at least one resource element pair; a step for determining a channel estimation value for the resource block on the basis of a channel estimation result pair corresponding to the at least one resource element pair, and determining an average value of at least one channel estimation value corresponding to the at least one resource block as a channel estimation value of the measurement cell; and a step for determining reference signal reception power of the measurement cell on the basis of the channel estimation value of the measurement cell.

Description

  The present invention relates to the field of communication technology, and in particular, to a method, a terminal, and a system for determining reference signal reception power.

  In the LTE system or LTE-A system, the terminal uses measurement configuration information (RSRP (Reference Signal Receiving Power) or RSRQ (Reference Signal Receiving Quality)) based on measurement configuration information provided by UTRAN (Universal Terrestrial Radio Access Network). ) To the base station. In LTE systems, typical RSRP measurements typically determine the reference signal received power of a cell using a cell specific reference signal in the measurement bandwidth.

であるとする。ここでは、r(l,i)は、受信した周波数領域上のセル特定リファレンス信号のシンボルであり、x(l,i)は、周波数領域がiであり且つ時間領域がlであるセル特定リファレンス信号のローカルコピー（l=0，1；0＜i＜2N_RB；N_RBは、周波数方向上のリソースブロック数である）であり、h(l,i)は、測定セルのチャネルレスポンスである。 FIG. 1 shows a general RSRP measurement method. The received signal is

Suppose that Here, r (l, i) is a symbol of a cell specific reference signal on the received frequency domain, and x (l, i) is a cell specific reference whose frequency domain is i and whose time domain is l Is a local copy of the signal (l = 0, 1; 0 <i <2N _RB ; N _RB is the number of resource blocks in the frequency direction), and h (l, i) is the channel response of the measurement cell .

2）パワーの計算：

3）RSRP（リファレンス信号受信パワー）の計算：RSRP=10×log10(P)。 1) Channel estimation of measurement cell:

2) Power calculation:

3) RSRP (reference signal received power) calculation: RSRP = 10 × log10 (P).

  In LTE Rel.10 and Rel.11, heterogeneous networks are widely used to solve problems such as load flow closure and cell range expansion. In 3GPP Rel-11 eICIC (referred to as FeICIC), the specific reference signal of the strong interference cell does not match the specific reference signal of the cell that received strong interference, and the specific cell of the measurement cell for ABS subframe measurement The signal to interference noise ratio of the reference signal is -9.4 dB. Therefore, CRSIC (Common Reference Signal Interference Rejection) based on the RSRP measurement method has been proposed in order to accurately measure the reception power of a specific cell reference signal of a cell that has received strong interference.

であるとする。ここでは、r(l,i)は、受信した周波数領域上のセル特定リファレンス信号のシンボルであり、x₀(l,i)及びx₁(l,i)は、それぞれ、周波数領域がiであり且つ時間領域がlである測定セル及び強干渉セルのセル特定リファレンス信号のローカルコピー（l=0，1；0＜i＜2N_RB；N_RBは、周波数方向上のリソースブロック数である）であり、h₀(l,i)及びh₁(l,i)は、それぞれ、測定セル及び強干渉セルのチャネルレスポンスである。 FIG. 2 shows a basic CRSIC measurement based on the RSRP measurement method. The received signal is

Suppose that Here, r (l, i) is a symbol of the cell specific reference signal on the received frequency domain, and x ₀ (l, i) and x ₁ (l, i) are respectively in the frequency domain i Local copy of cell-specific reference signal of measurement cell and strong interference cell with time domain being l (l = 0, 1; 0 <i <2N _RB ; N _RB is the number of resource blocks in the frequency direction) H ₀ (l, i) and h ₁ (l, i) are channel responses of the measurement cell and the strong interference cell, respectively.

そのうち、w(l,i)は、フィルターである。
2）強干渉セルの信号の生成：

3）強干渉セルの信号の除去：

4）測定セルのチャネル推定：

5）パワーの計算：

6）リファレンス信号の受信パワーの計算：RSRP=10×log10(P)。 1) Channel estimation of strong interference cell:

Of these, w (l, i) is a filter.
2) Strong interference cell signal generation:

3) Elimination of strong interference cell signal:

4) Channel estimation of measurement cell:

5) Power calculation:

6) Calculation of received power of reference signal: RSRP = 10 × log10 (P).

  With respect to a general method for measuring the received power of the reference signal, the measurement accuracy of the reference signal received power is low in FeICIC because it receives high power interference of strong interference cells in the heterogeneous network. In addition, with respect to the interference cancellation method, the channel estimation of the strong interference cell and the related cancellation steps are increased, which increases the computational complexity.

  At present, there is no conventional technique that can solve the above-described problems existing in the reference signal reception power measurement method.

  In view of the above-described problems, an object of the present invention is to provide a new reference signal reception power determination technique that can not only improve the measurement accuracy of a measurement cell but also reduce the calculation complexity. is there.

According to one aspect of the present invention, a method for determining reference signal received power is provided, the method comprising:
Generating two specific cell reference signals, the two specific cell reference signals being reference signals corresponding to the measurement cell and the interference cell, respectively;
For each resource block of at least one resource block of the measurement cell, based on the two specific cell reference signals and the received signal, a signal on each adjacent resource element having a reference signal in the resource block. Perform channel estimation for each resource element and obtain a channel estimation result corresponding to each resource element;
Pairing each adjacent resource element having a reference signal to obtain at least one pair of resource elements paired;
Based on a channel estimation result pair corresponding to the at least one resource element pair, a channel estimation value of each resource block is determined, and an average value of at least one channel estimation value corresponding to the at least one resource block is determined. Determining a channel estimation value of the measurement cell; and determining a reference signal reception power of the measurement cell based on the channel estimation value of the measurement cell.

  According to the technical solution of the present invention, channel estimation is performed based on the reference signal of the measurement cell and the reference signal of the strong interference cell, and the effect of the strong interference cell is effectively removed by performing resource element pairing. The measurement accuracy of weak cells can be improved.

It is a figure which shows the RSRP measuring method in a prior art. It is a figure which shows the CRSIC measuring method in a prior art. It is a figure which shows the correspondence of the bandwidth resource of the LTE system in a prior art. 3 is a flowchart of a method for receiving reference signal reception power according to an embodiment of the present invention; FIG. 6 is a diagram illustrating adjacent resource elements having a reference signal in a bandwidth resource. 6 is a flowchart of a method for receiving reference signal reception power according to another embodiment of the present invention; It is a block diagram of the terminal which concerns on one Example of this invention. 1 is a block diagram of a system according to an embodiment of the present invention.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings.

  Before describing the method for determining the reference signal reception power of the present invention, first, bandwidth resources in the LTE system will be briefly introduced based on FIG.

  As shown in FIG. 3, in the LTE system, one radio frame is 10 ms and includes 10 subframes whose subframe indexes are 0 to 9, each subframe is 1 ms, and one radio frame A subframe is divided into two time slots. In the normal cp mode, each time slot has seven Orthogonal Frequency Division Multiplexing (OFDM) symbols whose symbol index is l = 0 to l = 6. In the system, resources are allocated by allocating resource blocks RB, and the number of RBs allocated corresponding to different bandwidths is different. In the normal case, one RB includes time domain resources occupied by one time slot in time, and includes resources normally occupied by twelve subcarriers in frequency, and includes one resource on one OFDM symbol. A resource occupied by a subcarrier is referred to as a resource element RE (Resource Element).

  In the embodiment of the present invention, channel estimation of the measurement cell can be easily realized by jointing (combining) information of the specific reference signal of the measurement cell and the specific reference signal of the interference cell. In general, when there are multiple interference cells that interfere with the measurement cell, the interference cell for calculating the reference signal reception power of the measurement cell using the specific reference signal of the relatively strong cell from the multiple interference cells Of course, one interfering cell may be arbitrarily selected.

  FIG. 4A is a flowchart of a method for determining reference signal reception power according to an embodiment of the present invention.

  The method for determining the reference signal reception power according to this embodiment may include the following steps.

Step 410: Generate two specific cell reference signals, the two specific cell reference signals are reference signals corresponding to the measurement cell and the interference cell, respectively;
Step 412: For each resource block of at least one resource block of the measurement cell, on each adjacent resource element having a reference signal in the resource block based on the above two specific cell reference signals and the received signal Channel estimation is performed for each signal, and a channel estimation result corresponding to each resource element is obtained;
Step 414: Pairing for each adjacent resource element having a reference signal to obtain at least one paired resource element pair; based on the channel estimation result pair corresponding to the at least one resource element pair, Determining a channel estimate for each resource block, and taking an average of at least one channel estimate corresponding to at least one resource block as the channel estimate for the measurement cell;
Step 416: Determine the reference signal reception power of the measurement cell based on the channel estimation value of the measurement cell.

  In step 414, the step of performing pairing for each adjacent resource element having a reference signal and obtaining at least one paired resource element pair includes the following steps.

Calculating the phase difference between the reference signal on each adjacent resource element and the reference signal of the interfering cell;
A pairwise comparison is performed on each adjacent resource element having a reference signal based on the phase difference of each adjacent resource element to obtain a phase difference difference between adjacent resource elements of each pair;
A resource element pair whose phase difference difference is equal to or greater than a predetermined value is defined as the paired resource element pair.

  As shown in FIG. 4B, it is assumed that A1, A2, B1, and B2 are adjacent resource elements having a reference signal in one resource block, and pairing is performed for these resource elements. Before this, it is necessary to calculate the phase difference between the reference signal on each adjacent resource element and the reference signal of the interfering cell, and the four adjacent elements of the adjacent resource elements A1, A2, B1, and B2 are calculated. It is necessary to calculate the phase difference between the reference signal above and the reference signal of the interfering cell, and the phase differences corresponding to A1, A2, B1, and B2 obtained by the calculation are Q1, Q2, Q3 and Q4.

  Next, for each neighboring resource element, find (look up) the neighboring resource element that matched it (ie, paired with it). In the lookup process, it is necessary to calculate a pairwise difference between phase differences corresponding to two adjacent resource elements (ie, phase difference difference). For example, for the selected resource element A1, A1 And the corresponding phase difference between each of the other three adjacent resource elements, ie, the difference between Q1 and each of Q2, Q3 and Q4, and these Based on the difference, the adjacent resource element paired with A1 is determined.

  Specifically, when the difference in phase difference is equal to or greater than a predetermined value, the selected resource element and another adjacent resource element corresponding thereto are used as a resource element pair. Among them, the predetermined value may be an arbitrary value between 180 degrees, 90 degrees, 80 degrees, 70 degrees, 90 degrees to 80 degrees, or an arbitrary value between 80 degrees and 70 degrees, and Q1 and If the difference from Q2 is greater than or equal to a predetermined value, it means that A1 and A2 can be paired.

  Considering the time offset and frequency offset between the reference signal of the measurement cell and the reference signal of the interference cell, the reference signal on each adjacent resource element and the reference signal of the interference cell are used using these two parameters. It is necessary to correct the phase difference between them to ensure the accuracy of the calculated phase difference.

At the time of correction, the phase difference between the reference signal on each adjacent resource element and the reference signal of the interference cell is determined by the following phase calculation formula.

Of these, l is an OFDM symbol, i is a subcarrier symbol, θ (l, i) is a phase difference, x ₁ (l, i) is a reference signal of an interference cell, and x ₀ ( l, i) is the reference signal of the measurement cell, f _s is the sampling rate (rate), Δf is the frequency offset value, Δt is the time offset value, and N _FFT is the Fourier transform ΔT is the amount of data, and ΔT is between the reference signal of the selected resource element (eg, A1) and another adjacent resource element (eg, any one of A2, B1, B2). It is a time difference, and phase {} is a phase function.

  If a plurality of resource element pairs matched to one resource block are obtained, a plurality of channel estimation values are determined based on the plurality of resource element pairs, and an average value of the plurality of channel estimation values is determined as one resource. The channel estimation value corresponding to the block.

  For example, in the case of the above example, if A1 and A2 match and B1 and B2 match in one resource block, that is, if two pairs are found, based on one pair Since the channel estimate for the resource block can be calculated, two channel estimates for the resource block can be calculated based on the two pairs. In this case, the average value W1 of the two channel estimation values may be the channel estimation value of the current resource block, or the maximum value of the two channel estimation values may be the channel estimation value of the current resource block. It is good.

  Thus, if 50 resource blocks are selected, 50 channel estimation values can be calculated. Therefore, the average value of these 50 channel estimation values is used as the channel estimation value of the measurement cell, and the final value is calculated. Based on the channel estimation value, the reference signal received power of the measurement cell can be determined.

  If a matched resource element pair cannot be found from neighboring resource elements in the current resource block, the result (value) after weighting the channel estimation value on the neighboring resource block corresponds to the current resource block That is, if a resource element pair cannot be found from A1, A2, B1, B2, the channel estimate of one resource block before or after the current resource element block Let the value be the channel estimate for the current resource block.

  Hereinafter, it will be described in detail how the influence of the interference cell can be removed when channel estimation is performed on the measurement cell by the method for determining the reference signal reception power of the present invention.

In the above-described step 404, the zero forcing algorithm is adopted and channel estimation is performed on the reference signal on each adjacent resource element of the measurement cell by the following formula.

Among them, r (l, i) is the received signal, x ₀ (l, i) is the reference signal of the measurement cell, x ₁ (l, i) is the reference signal of the interference cell, n (l, i) is noise, l is an OFDM symbol, i is a subcarrier symbol, h ₀ (l, i) is the channel response of the measurement cell, and h ₁ (l , i) is the channel response of the interfering cell.

を有する。 That is, each adjacent element has a corresponding channel estimation result, i.e.

Have

であり、A2に対応するチャネル推定結果は、

である。式（1）と式（2）との和を求め、
（外１）

の未知項（
（外２）

は、既知項であり、
（外３）

は、常数である。）を除去すれば、即ち、干渉セルの測定セルへの影響を除去すれば、測定セルのチャネルレスポンスh₀を迅速に取得することができ、これにより、測定セルの測定精度を向上させることができ、言い換えると、干渉セルのチャネル推定レスポンスh₁を計算する必要がないので、計算複雑度を大幅に低減することができるだけでなく、測定セルのチャネル推定の正確度を大幅に向上させることもできる。 As described above, when a resource element pair is found in one resource block, if the paired resource element pair is A1 and A2, and the difference between the phase differences is 180 degrees, then A1 The corresponding channel estimation result is

And the channel estimation result corresponding to A2 is

It is. Find the sum of equation (1) and equation (2)
(Outside 1)

Unknown term (
(Outside 2)

Is a known term,
(Outside 3)

Is a constant. ), That is, if the influence of the interference cell on the measurement cell is removed, the channel response h ₀ of the measurement cell can be obtained quickly, thereby improving the measurement accuracy of the measurement cell. Yes, in other words, since it is not necessary to calculate the channel estimation response h ₁ of the interfering cell, not only can the computational complexity be greatly reduced, but also the accuracy of the channel estimation of the measuring cell can be greatly improved. it can.

  Next, a method for determining the reference signal reception power according to another embodiment of the present invention will be described with reference to FIG.

  In the present embodiment, channel estimation of the measurement cell can be easily realized by jointing information on the specific reference signal of the measurement cell and the specific reference signal of the strong interference cell.

であるとする。ここでは、r(l,i)は、受信した特定リファレンス信号であり、x₀(l,i)、x₁(l,i)は、それぞれ、測定セル及び強干渉セルの特定リファレンス信号のローカルコピーであり、h₀(l,i)及びh₁(l,i)は、それぞれ、測定セル及び強干渉セルのチャネルレスポンスである。 The signal received by the terminal

Suppose that Here, r (l, i) is the received specific reference signal, and x ₀ (l, i) and x ₁ (l, i) are local reference signals of the measurement cell and strong interference cell, respectively. H ₀ (l, i) and h ₁ (l, i) are channel responses of the measurement cell and the strong interference cell, respectively.

  Step 502: Generate a specific reference signal.

Based on the cell ID information, time slot symbol information, and ABS mode information, local copies x ₀ (l, i) and x ₁ (l, i) of the specific reference signal can be generated.

  Step 504: Perform ZF channel estimation for the resource element having the reference signal of the measurement cell.

The ZF channel response estimation of the measurement cell is h _ZF (l, i), i is the carrier symbol of the reference signal, and l is the OFDM symbol of the reference signal.

  Step 506: Calculate the difference between the phase difference of the pair.

The copy of the specific reference signal of the strong interference cell and the measurement cell is x ₀ (l, i) and x ₁ (l, i), respectively. Considering the time offset and frequency offset between two specific reference signals of the interfering cell, the phase difference between the frequency resources occupied by the specific reference signal between the two cells can be defined as follows.

Among them, Δt is a time offset between two cells, N _fft is a fast Fourier transform (FFT) algorithm, and can perform a fast Fourier transform with 128 points, l (0 or 1) is The time slot occupied by a specific reference signal, ΔT is the time interval between specific reference reference signals on two adjacent resource elements, Δf is the frequency offset between two cells, and f _s is The sampling rate (eg, 1.92 MHz), and * is a conjugate operation.

If there are four resource elements with a reference signal in the current resource block, the phase difference between each pair can be defined as follows:

  In the above pair, θ (0, i) is between the reference signal on one resource element in four neighboring resource elements on one resource block of the measurement cell and the reference signal of strong interference cell. The other can be analogized based on this.

  Step 508: Combine with the selected channel estimation result pair to estimate the channel response of the measurement cell.

  When the difference between the above phase differences is a predetermined value, for example, 90 degrees or more (that is, when a resource element pair having a phase difference close to 180 degrees is found), the resource element pair is selected as the selected resource element pair. Then, channel estimation for the measurement cell is realized using these selected resource element pairs, and a channel estimation value of one measurement cell is obtained for each resource block.

  If there is no matched pair in the current resource block, a special processing process for neighboring channel estimation is performed, that is, the channel estimation value of the neighboring resource block is set as the channel estimation value of the current resource block. If the resource block is 100 blocks, there are 100 corresponding channel estimation values. In this case, the 100 channel estimation values are used as the final channel estimation values of the measurement cell. It should be understood that the greater the number of selected resource blocks, the higher the accuracy of channel estimation of the measurement cell.

に基づいてパワーを計算する。 Step 510: Formula

Calculate power based on.

  Step 512: Finally, the received power of the reference signal is calculated, that is, RSRP = 10 × log10 (P).

  By combining the signals of the measurement cell and the interference cell, the channel response of the measurement cell is obtained, a matching resource element pair is found in the channel response calculation process, and a pair of channels of the paired resource element pair Since the influence of the interference cell is removed based on the estimation result, the channel response of the measurement cell can be obtained directly without performing the channel estimation of the interference cell, so that the computational complexity can be reduced and the Since there is a certain error in the channel estimation of the interference cell and the influence removal step of the strong interference cell, the channel estimation accuracy of the measurement cell can be further improved by the measurement method according to the embodiment of the present invention.

  The terminal configuration corresponding to the execution steps shown in FIG. 5 is shown in FIG.

  As shown in FIG. 6, a terminal 600 according to an embodiment of the present invention includes a reference signal generation unit 602, a first channel estimation unit 604, a pairing unit 606, a second channel estimation unit 608, and a power determination unit 610. Among them, the reference signal generation unit 602 is used to generate two specific cell reference signals, and the two specific cell reference signals are reference signals corresponding to the measurement cell and the interference cell, respectively; Unit 604 performs channel estimation for the signal on each resource element having the reference signal of the measurement cell based on two specific cell reference signals and the received signal for each resource block of at least one resource block. Used to obtain channel estimation results corresponding to each resource element; pairing unit 606 performs pairing on neighboring resource elements having a reference signal and obtains at least one resource element pair Is The second channel estimation unit 608 determines a channel estimation value for each resource block based on a channel estimation result pair corresponding to at least one resource element pair, and at least one channel estimation value corresponding to at least one resource block. The power determination unit 610 is used to determine the reference signal received power of the measurement cell based on the channel estimation value of the measurement cell.

Among them, the first channel estimation unit 604 employs Zero Forcing Algorithm to perform channel estimation on the reference signal on each adjacent resource element of the measurement cell according to the following equation.

Among them, r (l, i) is the received signal, x ₀ (l, i) is the reference signal of the measurement cell, x ₁ (l, i) is the reference signal of the interference cell, n (l, i) is noise, l is an OFDM symbol, i is a subcarrier symbol, h ₀ (l, i) is the channel response of the measurement cell, and h ₁ (l , i) is the channel response of the interfering cell.

  Further, the pairing unit 606 may include the following subunits.

Phase difference calculation subunit 6062: used to calculate the phase difference between the reference signal on each adjacent resource element and the reference signal of the interfering cell;
Difference value calculation subunit 6064: for one selected resource element of adjacent resource elements having a reference signal, the corresponding phase difference of the selected resource element and the corresponding phase difference of each other adjacent resource element Used to calculate the difference between
Pairing subunit 6066: used to determine adjacent resource elements that are paired with the selected resource element based on the calculated phase difference difference. Specifically, when the difference is equal to or greater than a predetermined value, the pairing unit 606 sets the selected resource element and another corresponding resource element as a resource element pair.

  The phase difference calculation subunit 6062 further includes a reference signal on each adjacent resource element, a reference signal of the interference cell, and a reference signal of the interference cell based on a time offset and a frequency offset between the reference signal of the measurement cell and the reference signal of the interference cell. Is used to correct the phase difference between.

Among them, the phase difference calculation subunit 6062 determines the phase difference between the reference signal on each resource element and the reference signal of the interference cell based on the following phase calculation formula.

Of these, l is an OFDM symbol, i is a subcarrier symbol, θ (l, i) is a phase difference, x ₁ (l, i) is a reference signal of an interference cell, and x ₀ ( l, i) is the reference signal of the measurement cell, f _s is the sampling rate, Δf is the frequency offset value, Δt is the time offset value, and N _FFT is the Fourier transform data amount ΔT is a time difference between a reference signal on the selected resource element and a reference signal on another adjacent resource element, and phase {} is a phase function.

  The second channel estimation unit 608 further determines a plurality of channel estimation values based on the plurality of resource element pairs when obtaining a plurality of matched resource element pairs for one resource block, and determines a plurality of channel estimation values. Is used as a channel estimation value corresponding to one resource block.

  When the second channel estimation unit 608 does not find a resource element matching the selected resource element from other neighboring resource elements, the second channel estimation unit 608 weights the channel estimation value on the neighboring resource block, Used to obtain a channel estimate corresponding to the current resource block.

  The reference signal generation unit 602 is further used to set a reference signal of one power maximum cell as a reference signal of the interference cell from these interference cells when the number of cells that interfere with the measurement cell is two or more. . Of course, the reference signal of one of the cells may be arbitrarily selected and used as the reference signal of the interference cell.

  FIG. 7 is a block diagram of a system according to an embodiment of the present invention.

  As shown in FIG. 7, the present invention further provides a system 700, which includes a base station 702 and a terminal 600 shown in FIG.

  In addition, the present invention further provides a computer-readable program (not shown), and when the program is executed in the base station, the program determines the above-mentioned reference signal reception power in the computer at the base station. To execute the method to do.

  The present invention further provides a storage medium (not shown) storing a computer-readable program, wherein the computer-readable program causes a computer to execute the above-described method for determining the reference signal reception power at a terminal. .

  Specifically, when the above-described computer-readable program is executed in a base station or a terminal, the base station or terminal causes the computer to generate “two specific cell reference signals, and the two specific cell reference signals are Reference signals corresponding to the measurement cell and the interference cell, respectively; for each resource block of at least one resource block of the measurement cell, the resource block based on the two specific cell reference signals and the received signal Channel estimation is performed on a signal on each adjacent resource element having a reference signal, and a channel estimation result corresponding to each resource element is obtained; pairing is performed on each adjacent resource element having a reference signal. ) Obtaining at least one resource element pair that is ainged; determining a channel estimation value of each resource block based on a channel estimation result pair corresponding to the at least one resource element pair; A reference value including: determining an average value of the corresponding at least one channel estimation value as a channel estimation value of the measurement cell; and determining a reference signal reception power of the measurement cell based on the channel estimation value of the measurement cell A method for determining the received signal power is executed.

  The present invention obtains the channel response of the measurement cell based on the signals of the measurement cell and the interference cell, and finds a matched resource element pair in the calculation process of the channel response. Since the influence of the interference cell is removed based on the pair of channel estimation results, the channel response of the measurement cell can be directly obtained without performing channel estimation of the interference cell, so that the calculation complexity can be reduced. In addition, since there is a certain error in the channel estimation of the strong interference cell and the influence removal step of the strong interference cell, the measurement method according to the embodiment of the present invention can further improve the channel estimation accuracy of the measurement cell. it can.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to this embodiment, and all modifications to the present invention belong to the technical scope of the present invention unless departing from the spirit of the present invention.

Claims (19)

A method for determining reference signal received power,
Generating two specific cell reference signals, the two specific cell reference signals being reference signals for the measurement cell and the interference cell, respectively;
For each resource block of at least one resource block of the measurement cell, based on the two specific cell reference signals and the received signal, a signal on each adjacent resource element having a reference signal in the resource block. Channel estimation is performed for each adjacent resource element to obtain a channel estimation result;
Pairing with each adjacent resource element having a reference signal to obtain at least one resource element pair;
Based on a channel estimation result pair corresponding to the at least one resource element pair, a channel estimation value of each resource block is determined, and an average value of at least one channel estimation value corresponding to the at least one resource block is determined. And determining a reference signal received power of the measurement cell based on the channel estimate of the measurement cell. The method of claim 1, comprising
Pairing adjacent resource elements having the reference signal and obtaining at least one resource element pair includes:
Calculating the phase difference between the reference signal on each adjacent resource element and the reference signal of the interfering cell;
Based on the phase difference of each adjacent resource element, a pair comparison is performed for each adjacent resource element having a reference signal to obtain a phase difference difference between adjacent resource elements of each pair; and based on the phase difference difference Determining neighboring resource elements to become bearers. A method according to claim 2, comprising
A method in which a resource element pair having a phase difference difference equal to or greater than a predetermined value is set as the resource element pair. A method according to claim 2, comprising
When a plurality of resource element pairs are obtained for one resource block, a plurality of channel estimation values are determined based on the plurality of resource element pairs, and an average value of the plurality of channel estimation values is determined as the one resource block. A channel estimate corresponding to. A method according to claim 2, comprising
Based on the time offset and frequency offset between the reference signal of the measurement cell and the reference signal of the interference cell, the phase difference between the reference signal on each adjacent resource element and the reference signal of the interference cell To fix the way. The method according to claim 5, wherein a phase difference between a reference signal on each adjacent resource element and a reference signal of the interfering cell is determined by the following equation:

Of these, l is an OFDM symbol, i is a subcarrier symbol, θ (l, i) is the phase difference, x ₁ (l, i) is a reference signal of the interference cell, x ₀ (l, i) is a reference signal of the measurement cell, f _s is a sampling rate, Δf is a frequency offset value, Δt is a time offset value, and N _FFT is a Fourier transform A method wherein the amount of data is large, ΔT is a time difference between reference signals on two adjacent resource elements, and phase {} is a phase function. A method according to claim 2, comprising
When a resource element pair cannot be obtained from each of the adjacent resource elements, a method of weighting the channel estimation value on the adjacent resource block is a channel estimation value corresponding to the current resource block. The method of claim 1, comprising
Employing Zero Forcing Algorithm, channel estimation is performed for the reference signal on each adjacent resource element of the measurement cell by the following formula,

Among them, r (l, i) is the received signal, x ₀ (l, i) is the reference signal of the measurement cell, and x ₁ (l, i) is the reference signal of the interference cell. N (l, i) is noise, l is an OFDM symbol, i is a subcarrier symbol, h ₀ (l, i) is a channel response of the measurement cell, h ₁ (l, i) is the channel response of the interfering cell. A method according to any one of claims 1 to 8, comprising
If the number of cells that interfere with the measurement cell is two or more, the method further comprises selecting a reference signal of one power-maximum cell from these cells as a reference signal of the interference cell. A terminal,
A reference signal generation unit for generating two specific cell reference signals, wherein the two specific cell reference signals are reference signals corresponding to a measurement cell and an interference cell, respectively;
For each resource block of at least one resource block of the measurement cell, based on the two specific cell reference signals and the received signal, a signal on each adjacent resource element having a reference signal in the resource block. A first channel estimation unit that performs channel estimation on the channel and obtains a channel estimation result corresponding to each adjacent resource element;
A pairing unit that performs pairing for each adjacent resource element having a reference signal and obtains at least one resource element pair;
Based on a channel estimation result pair corresponding to the at least one resource element pair, a channel estimation value of each resource block is determined, and an average value of at least one channel estimation value corresponding to the at least one resource block is determined. A terminal comprising: a second channel estimation unit that is a channel estimation value of the measurement cell; and a power determination unit that determines a reference signal reception power of the measurement cell based on the channel estimation value of the measurement cell. The terminal according to claim 10, wherein
The pairing unit is
A phase difference calculation subunit for calculating a phase difference between a reference signal on each adjacent resource element and a reference signal of the interfering cell;
A difference value calculation subunit that performs a pair comparison for each adjacent resource element having a reference signal based on the phase difference of each adjacent resource element and obtains a phase difference difference between adjacent resource elements of each pair; and A terminal including a pairing subunit that determines adjacent resource elements to be paired based on a difference in phase difference. The terminal according to claim 11, wherein
The pairing unit is a terminal in which a resource element pair whose phase difference is equal to or greater than a predetermined value is the resource element pair. The terminal according to claim 11, wherein
The second channel estimation unit further determines a plurality of channel estimation values based on the plurality of resource element pairs when obtaining a plurality of the resource element pairs for one resource block, and A terminal used for setting an average value of values as a channel estimation value corresponding to the one resource block. The terminal according to claim 11, wherein
The phase difference calculation subunit further includes a reference signal on each adjacent resource element based on a time offset and a frequency offset between the reference signal of the measurement cell and the reference signal of the interference cell, and the interference cell A terminal used to correct a phase difference from a reference signal. The terminal according to claim 14, wherein
The phase difference calculation subunit determines a phase difference between a reference signal on each adjacent resource element and a reference signal of the interference cell according to the following formula:

Of these, l is an OFDM symbol, i is a subcarrier symbol, θ (l, i) is the phase difference, x ₁ (l, i) is a reference signal of the interference cell, x ₀ (l, i) is a reference signal of the measurement cell, f _s is a sampling rate, Δf is a frequency offset value, Δt is a time offset value, and N _FFT is a Fourier transform A terminal, which is the amount of data, ΔT is the time difference between reference signals on two adjacent resource elements, and phase {} is a phase function. The terminal according to claim 11, wherein
The second channel estimation unit further provides a channel corresponding to the current resource block after weighting the channel estimation value on the adjacent resource block when a resource element pair cannot be obtained from each adjacent resource element. A terminal used to make an estimate. The terminal according to claim 10, wherein
The first channel estimation unit employs Zero Forcing Algorithm to perform channel estimation for the reference signal on each adjacent resource element of the measurement cell according to the following formula:

Among them, r (l, i) is the received signal, x ₀ (l, i) is the reference signal of the measurement cell, and x ₁ (l, i) is the reference signal of the interference cell. N (l, i) is noise, l is an OFDM symbol, i is a subcarrier symbol, h ₀ (l, i) is a channel response of the measurement cell, h ₁ (l, i) is a terminal that is a channel response of the interference cell. A terminal according to any one of claims 10 to 17,
The reference signal generation unit further uses, when the number of cells that interfere with the measurement cell is two or more, to use a reference signal of one cell having the maximum power as a reference signal of the interference cell from these cells. Used terminal.   19. A system comprising a base station and a terminal according to any one of claims 10-18.

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