CN103379078B - A kind of method and apparatus of frequency domain equalization detection - Google Patents

Abstract

The method and apparatus that the invention discloses the detection of a kind of frequency domain equalization, the method includes: calculate the noise interference covariance matrix Re_pilot of pilot sub-carrier and the noise interference covariance matrix Re_Data of data subcarrier；Employing AF panel merges IRC detection mode or Maximal ratio combiner MRC detection mode carries out frequency domain equalization detection to utilize the noise interference covariance matrix Re_pilot of described pilot sub-carrier or the noise interference covariance matrix Re_Data of data subcarrier to determine.In the embodiment of the present invention, frequency domain equalization detection is carried out by adaptive selection MRC detection mode or IRC detection mode, make when interference plays a leading role in receiving signal, it is possible to by above-mentioned interference and noise range divisional processing, it is possible to fully ensure that detection performance；When interference does not play a leading role in receiving signal, will not cause that computational accuracy declines due to the introducing of channel estimation errors, it is possible to fully ensure that detection performance.

Description

Method and equipment for frequency domain equalization detection

Technical Field

The present invention relates to the field of communications technologies, and in particular, to a method and an apparatus for frequency domain equalization detection.

Background

(1) Time-frequency domain structure of uplink data signal and pilot signal of LTE (Long term evolution) system.

The time-frequency domain structure of PUSCH (physical uplink shared channel) in subframe n is: the time domain occupies one subframe (1ms), the frequency domain occupies N PRBs (physical resource blocks), and each PRB occupies 12 SCs (subcarriers) in the frequency domain. Each subframe contains two columns of PUSCH pilot frequency, and under a conventional CP (cyclic prefix), a pilot frequency signal of the PUSCH is positioned in a fourth column of SC-FDMA (Single Carrier-frequency division multiple Access) symbols; under the extended CP, the pilot signal is located at the third column SC-FDMA symbol.

The PUSCH frequency hopping has two modes of intra-subframe frequency hopping and inter-subframe frequency hopping, and the following combinations are provided: the combination is as follows: no frequency hopping is carried out between subframes and in subframes; combining two: not hopping frequency among subframes and hopping frequency in subframes; combining three components: frequency hopping among subframes and no frequency hopping in the subframes; and (4) combining: inter-subframe frequency hopping and intra-subframe frequency hopping.

Fig. 1 and fig. 2 show the position structures of PUSCH data symbols and pilot symbols corresponding to combination one and combination two, respectively, under the conventional CP condition. Two columns of SC-FDMA symbols marked by reverse slashes are pilot symbols, and the other 12 columns of SC-FDMA symbols are data symbols.

(2) MRC (maximum ratio combining) detection mode.

An eNodeB (evolved node B, base station) performs uplink channel estimation to obtain a channel response estimation value of a target user (i, 1) in a target cell i

In the frequency domain equalization detection process, under the Least Square (LS) -MRC criterion, the estimated value of a transmitted symbol is as follows:

${\hat{s}}_i=w^{H}r={\left[{\hat{H}}_{i,1}^H{\hat{H}}_{i,1}\right]}^{-1}{\hat{H}}_{i,1}^{H}r;$

in the frequency domain equalization detection process, under the Minimum Mean Square Error (MMSE) -MRC criterion, the estimated value of the transmitted symbol is:

${\hat{s}}_i=w^{H}r={[{\hat{H}}_{i,1}^H{\hat{H}}_{i,1}+{\mathrm{\δ}}_n^2{I}_{N_T}]}^{-1}{\hat{H}}_{i,1}^{H}r.$

(3) IRC (interference rejection combining) detection mode.

eNodeB carries out uplink channel estimation to obtain a channel response estimation valueAnd further calculating to obtain a covariance matrix of noise and interference

In the frequency domain equalization detection process, under the Least Square (LS) -IRC criterion, the estimated value of a transmitted symbol is as follows:

${\hat{s}}_i=w^{H}r={\left[{\hat{H}}_{i,1}^H{\hat{R}}_e^{-1}{\hat{H}}_{i,1}\right]}^{-1}{\hat{H}}_{i,1}^H{\hat{R}}_e^{-1}r;$

in the frequency domain equalization detection process, under the Minimum Mean Square Error (MMSE) -IRC criterion, the estimated value of a transmission symbol is:

${\hat{s}}_i=w^{H}r={[{\hat{H}}_{i,1}^H{\hat{R}}_e^{-1}{\hat{H}}_{i,1}+I_{N_T}]}^{-1}{\hat{H}}_{i,1}^H{\hat{R}}_e^{-1}r.$

(4) and the LTE system uplinks a received signal model under the condition of intercell interference.

Suppose that the eNodeB supports K cells at most, the target cell is i, the interfering cell is j (0 ≦ j ≦ K-1), a UE (user equipment) signal from the target cell i is an expected signal, and a UE signal from the interfering cell j is an interfering signal; then, in the target cell i, a UE with user ID (i, 1) is scheduled, and the UE transmits a signal of (i, 1)The channel response is

Assuming that the cell radius is small, the signals received by the eNodeB from the multi-cell UE are substantially synchronized, and the length of the CP (cyclic prefix) is much longer than the delay spread of the wireless channel, each subcarrier experiences approximately flat fading, and an equivalent frequency domain mathematical model can be expressed as:

r＝H^cell_id0s^cell_id0+H^cell_id1s^cell_id1+...+H^cell_id(K-1)s^cell_id(K-1)+ N wherein (C) is the alkyl group,

＝Hs+N

H＝[H^cell_id0，H^cell_id1，...，H^cell_id(K-1)]，H^cell_id(k)denotes a channel response of a UE having a cell ID K, K being 0, 1.. K-1, and K denotes the number of cells supported inside one eNodeB.

Furthermore, s ═ c^ell_id0，s^cell_idl，...，s^cell_id(K-1)]^T，s^cell_id(k)K-1, s, which is 0, 1^cell_id(k)∈ Ω, Ω represent a set of constellation points, (. o)^TTranspose of the expression; n represents noise, obeys a mean of 0 and a variance of²Complex gaussian distribution.

Further, definei＝0，1，...K-1，The received signal expression is:

$r=H_{i,1}{s}_{i,1}+\underset{j=0,j\≠i}{\overset{K-1}{\mathrm{\Σ}}}{H}_j{s}_j+N=H_{i,1}{s}_{i,1}+I+N.$

in the process of implementing the invention, the inventor finds that at least the following problems exist in the prior art:

in the prior art, only the MRC detection mode or the IRC detection mode can be selected fixedly for detection, and analysis of the received signal expression shows that when interference plays a leading role in receiving signals, the MRC detection mode only treats the interference as noise, which inevitably causes rapid deterioration of detection performance; when interference does not play a dominant role in receiving signals, the IRC detection method will cause the calculation accuracy to be reduced due to the introduction of channel estimation errors, and will cause the detection performance to be reduced.

Disclosure of Invention

The embodiment of the invention provides a method and equipment for frequency domain equalization detection, which are used for carrying out frequency domain equalization detection by adaptively selecting an MRC detection mode or an IRC detection mode so as to ensure the detection performance.

In order to achieve the above object, an embodiment of the present invention provides a frequency domain equalization detection method, including:

calculating a noise interference covariance matrix Re _ pilot of the pilot frequency sub-carrier;

and determining to adopt an Interference Rejection Combining (IRC) detection mode or a Maximum Ratio Combining (MRC) detection mode to perform frequency domain equalization detection by using the noise interference covariance matrix Re _ pilot of the pilot frequency subcarrier.

The embodiment of the invention provides a frequency domain equalization detection device, which comprises:

the calculation module is used for calculating a noise interference covariance matrix Re _ pilot of the pilot frequency subcarrier;

and the determining module is used for determining that the interference suppression combination IRC detection mode or the maximum ratio combination MRC detection mode is adopted to carry out frequency domain equalization detection by utilizing the noise interference covariance matrix Re _ pilot of the pilot frequency subcarrier.

Compared with the prior art, the embodiment of the invention at least has the following advantages: in the embodiment of the invention, the frequency domain equalization detection is carried out by adaptively selecting the MRC detection mode or the IRC detection mode, so that when the interference plays a leading role in receiving signals, the interference and the noise can be distinguished and processed, and the detection performance can be fully ensured; when the interference does not play a leading role in receiving signals, the calculation precision is not reduced due to the introduction of channel estimation errors, and the detection performance can be fully ensured.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.

FIG. 1 is a diagram of data symbol and pilot symbol positions during non-frequency hopping between subframes and within subframes in the prior art;

FIG. 2 is a diagram of positions of data symbols and pilot symbols when no frequency hopping is performed between subframes and frequency hopping is performed within subframes in the prior art;

fig. 3 is a schematic flowchart of a method for frequency domain equalization detection according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a frequency domain equalization detection apparatus according to a second embodiment of the present invention.

Detailed Description

The technical solutions in the present invention will be described clearly and completely with reference to the accompanying drawings, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example one

The downlink of an LTE system adopts OFDMA (orthogonal frequency division multiple access), the uplink adopts SC-FDMA technology, users in cells are orthogonal to each other, no interference exists, but the same frequency band is used among the cells, the interference among the cells becomes main interference, in many practical scenes, the LTE uplink is an interference limited system, and narrow-band interference may exist in certain PRB (physical resource block) bandwidths; in an interference limited system (strong interference among users or co-channel interference caused by frequency reuse exists in the system), when the interference plays a leading role in receiving signals, the MRC detection mode treats the interference as noise, and the performance of the IRC detection mode is superior to that of the MRC detection mode; when the interference does not play a dominant role in receiving signals, the detection performance is reduced due to the IRC detection mode, and the performance of the MRC detection mode is superior to that of the IRC detection mode.

In view of the above discovery, an embodiment of the present invention provides a method for frequency domain equalization detection, which may be applied in an LTE system, and performs frequency domain equalization detection by adaptively selecting an MRC detection mode or an IRC detection mode, where when interference plays a dominant role in receiving a signal, the performance of the IRC detection mode is superior to that of the MRC detection mode, so that the frequency domain equalization detection is performed by the IRC detection mode, which may distinguish and process interference and noise, and fully ensure detection performance; when the interference does not play a leading role in receiving signals, the performance of the MRC detection mode is superior to that of the IRC detection mode, so that the frequency domain equalization detection is carried out through the MRC detection mode, the calculation precision is not reduced, and the detection performance is fully ensured.

As shown in fig. 3, the frequency domain equalization detection method includes the following steps:

step 301, calculating a noise interference covariance matrix Re _ pilot of the pilot subcarriers.

In the embodiment of the present invention, the process of calculating the noise interference covariance matrix Re _ pilot of the pilot subcarriers specifically includes: for a target user in an uplink target cell, channel estimation of a pilot frequency subcarrier is carried out to obtain a channel response estimation value H _ pilot, and a noise interference covariance matrix Re _ pilot of the pilot frequency subcarrier is calculated by utilizing the channel response estimation value H _ pilot.

And step 302, determining to adopt an IRC detection mode or an MRC detection mode to carry out frequency domain equalization detection by using a noise interference covariance matrix Re _ pilot of the pilot frequency subcarrier.

In the embodiment of the invention, the frequency domain equalization detection can be directly carried out by determining the adoption of an IRC detection mode or an MRC detection mode through the noise interference covariance matrix Re _ pilot of the pilot frequency subcarrier; or, calculating a noise interference covariance matrix Re _ data of the data subcarrier by using the noise interference covariance matrix Re _ pilot of the pilot frequency subcarrier, and determining to adopt an IRC detection mode or an MRC detection mode to carry out frequency domain equalization detection by using the noise interference covariance matrix Re _ data of the data subcarrier.

In the embodiment of the present invention, it is assumed that there is one target user (i, 1) in an uplink target cell i of an LTE system, and the following variables are defined: i represents the number of a target cell, slot represents the number of a time slot, symbol represents the number of SC-FDMA symbols, SC represents the number of subcarriers, and NR represents the number of uplink receiving antennas; and the number of the first and second groups,indicating the pilot signal of the sc pilot subcarrier of the target user (i, 1) in the slot-th time slot, and the pilot signal is a scalar;represents the received signal on the sc pilot subcarrier in the slot time slot, which is N_RColumn vectors of dimension × 1;represents the channel response estimate for the target user (i, 1) on the sc-th pilot subcarrier in the target cell i, slot, and is N_RColumn vectors of dimension × 1;represents the received signal on the SC-th pilot sub-carrier on the SC-FDMA symbol of the symbol number and is N_RColumn vectors of dimension × 1.

In the embodiment of the present invention, obtaining the channel response estimation value H _ pilot by performing channel estimation on the pilot subcarriers specifically includes: receiving signal based on pilot frequency subcarrierAnd pilot signals assigned to target usersPerforming channel estimation to obtain channel response estimation value

In the embodiment of the present invention, calculating a noise interference covariance matrix Re _ pilot of a pilot subcarrier by using a channel response estimation value H _ pilot specifically includes: for each pilot frequency subcarrier in each slot, calculating the noise interference covariance matrix of each pilot frequency subcarrier according to the following formula

${\hat{R}e}_{\mathrm{slot},\mathrm{sc}}^{i,\mathrm{pilot}}=E\left[{\left|\right|r_{\mathrm{slot},\mathrm{sc}}^{i,\mathrm{pilot}}-{\hat{H}}_{\mathrm{slot},\mathrm{sc}}^{i,1}{s}_{\mathrm{slot},\mathrm{sc}}^{i,1}\left|\right|}_2^2\right]$

And calculating the noise interference covariance matrix of the averaged pilot subcarriers corresponding to all the pilot subcarriers in one PRB according to the following formula

${\hat{R}e}_{n_{\mathrm{RB}}}^{i,\mathrm{pilot}}=\frac{1}{N_{\mathrm{sc}}^{\mathrm{RB}}}\underset{\mathrm{sc}=N_{\mathrm{sc}}^{\mathrm{RB}}{n}_{\mathrm{RB}}}{\overset{N_{\mathrm{sc}}^{\mathrm{RB}}(n_{\mathrm{RB}}+1)-1}{\mathrm{\Σ}}}\left({\hat{R}e}_{\mathrm{slot},\mathrm{sc}}^{i,\mathrm{pilot}}\right)$

It should be noted that it is preferable that,represents the conjugate transpose of vector a multiplied by a, i.e.:E[A]a mathematical expectation (or average) representing the vector a/matrix a;representing the number of subcarriers contained in one PRB; n is_RBIndicating the number of the current PRB.

Taking the number of subcarriers included in one PRB as 12 as an example, the noise interference covariance matrix of the pilot subcarriers is calculated by taking the 12 subcarriers of one PRB as a basic unitSpecifically, for each pilot subcarrier in each slot, a noise interference covariance matrix of each pilot subcarrier is calculatedThereafter for pilot sub-carriers with 12 sub-carriers as basic unitCarrying out averaging to obtain the average Indicates the number of subcarriers included in one PRB.

Further, there may beThe simplified calculation method can be known from the characteristics of the LTE pilot signal: pilot sequence s_iThe modulus value is 1, i.e. | | s_i1, then:

$R_e=E\left[{\left|\right|r{-H}_i{s}_i\left|\right|}_2^2\right]=E\left[{\left|\right|\frac{r-H_i{s}_i}{s_i}\left|\right|}_2^2\right]=E\left[{\left|\right|\frac{r}{s_i}-H_i\left|\right|}_2^2\right]$

in the above-mentioned formula,represents the conjugate transpose of vector a multiplied by a, i.e.:E[A]represents the mathematical expectation (or average) of the vector a/matrix a, r represents the frequency domain received signal; furthermore, R_eCan be obtained by the difference between the initial channel estimation value (received signal divided by pilot sequence) of user i and the channel estimation value of user i after noise suppression processing.

In the embodiment of the present invention, based on whether there is PUSCH intraframe hopping, a process of calculating a noise interference covariance matrix Re _ data of a data subcarrier using a noise interference covariance matrix Re _ pilot of a pilot subcarrier specifically includes: when no PUSCH intra-subframe frequency hopping exists, time slot interpolation operation needs to be carried out on the noise interference covariance matrix Re _ pilot of the pilot frequency subcarrier to obtain the noise interference covariance matrix Re _ data of the data subcarrier on each SC-FDMA symbol; or, when there is PUSCH intra-subframe hopping, then for an SC-FDMA symbol within one slot, the noise-interference covariance matrix Re _ data of the data subcarriers on the same frequency band needs to be equal to the noise-interference covariance matrix Re _ pilot of the pilot subcarriers within the slot.

In the embodiment of the invention, the frequency domain equalization detection can be directly determined by adopting an IRC detection mode or an MRC detection mode based on the noise interference covariance matrix Re _ pilot of the pilot frequency subcarrier; or, the frequency domain equalization detection can be directly determined to be performed by adopting an IRC detection mode or an MRC detection mode based on the noise interference covariance matrix Re _ data of the data subcarrier; based on this, the process of determining to perform frequency domain equalization detection by using an IRC detection mode or an MRC detection mode specifically includes:

the ratio of the noise power to the interference power (referred to as "noise-to-interference ratio") is calculated according to the following formula:

$\mathrm{\η}=\frac{\mathrm{mean}\left(\mathrm{diag}\left(R_e\right)\right)}{\mathrm{mean}\left(\mathrm{abs}(R_e-\mathrm{diag}\left(\mathrm{diag}\left(R_e\right)\right))\right)}-1=\frac{\mathrm{\β}}{\mathrm{\α}}-1;$

when η is greater than a predetermined threshold (NIR _ th), then the noise power is considered to be less than the interference power, R_eAnd when η is not more than a preset threshold value (NIR _ th), the noise power is considered to be more than or equal to the interference power, and the frequency domain equalization detection needs to be carried out on each subcarrier by adopting an MRC detection mode.

In the above formula, mean (a) represents the average value of vector a, diag (a) represents the diagonal elements of extraction matrix a, and abs (a) represents the absolute value of vector a; and the number of the first and second groups,

β＝mean(diag(R_e) And it is R)_eThe average value of the diagonal elements of the matrix can be regarded as the average power of interference and noise; and the number of the first and second groups,

α＝mean(abs(R_e-diag(diag(R_e) ))) and is R)_eThe average of the modulus values of the off-diagonal elements of the matrix is approximated as the average power of the interference.

It should be noted that when the noise interference covariance matrix Re _ pilot of the pilot subcarriers is directly used to determine that the IRC detection mode or the MRC detection mode is used for frequency domain equalization detection, then R is_eThe noise-interference covariance matrix Re pilot by pilot sub-carriers is needed (e.g. as) Determining; when the noise interference covariance matrix Re _ data of the data subcarriers is used for determining that the frequency domain equalization detection is carried out by adopting an IRC detection mode or an MRC detection mode, then R_eNeeds to be determined by the noise-interference covariance matrix Re _ data of the data subcarriers.

In the embodiment of the present invention, the process of performing frequency domain equalization detection by using an IRC detection mode or an MRC detection mode includes: receiving signals using data subcarriersChannel estimation response matrix for data subcarriersAnd the noise interference covariance matrix of the updated data subcarriersCarrying out frequency domain equalization detection on each data subcarrier; for example, after determining to perform frequency domain equalization detection by MRC detection, the received signal of the data subcarrier is usedChannel estimation response matrixAnd the noise interference covariance matrix of the updated data subcarriersAnd the frequency domain equalization detection under the Least Square (LS) -MRC criterion or the Minimum Mean Square Error (MMSE) -MRC criterion is carried out.

Channel estimation response matrix based on whether there is PUSCH intra-subframe frequency hoppingThe determination method specifically comprises the following steps: when not in storageWhen frequency hopping is carried out in PUSCH sub-frame, the pairPerforming interpolation operation between time slots to obtain a channel estimation response matrix of a data subcarrier on each SC-FDMA symbolOr, when there is PUSCH intra-sub-frame frequency hopping, then for all SC-FDMA symbols within one slot, the equivalent channel estimation response matrix for the data sub-carriers on the same bandEqual to pilot sub-carrier in the slot

In addition, the noise interference covariance matrix of the updated data subcarriersThe determination method specifically comprises the following steps: determining a noise interference covariance matrix of the updated data subcarriers according to the following formula ${\hat{R}e}_{n_{\mathrm{RB}}}^{i,\mathrm{Data}\left(\mathrm{new}\right)};$

${\hat{R}e}_{n_{\mathrm{RB}}}^{i,\mathrm{Data}\left(\mathrm{new}\right)}=A1\×{\hat{R}e}_{n_{\mathrm{RB}}}^{i,\mathrm{Data}}+A2\×I;$

It should be noted that when the frequency domain equalization detection is performed by using the IRC detection method, a1 is equal to 1.0, and a2 is equal to 0.0; when the frequency domain equalization detection is performed by using the MRC detection method, a1 is equal to 0.0,and it isThe average of the diagonal elements of the matrix is the average power of the interference and noise; further, I denotes an identity matrix.

In a preferred implementation manner of the embodiment of the present invention, the received signal may be based on a data subcarrierChannel estimation response matrixAnd the noise interference covariance matrix of the updated data subcarriersCarrying out frequency domain equalization detection on each data subcarrier under an LS (least squares) criterion; and obtaining the estimation value of the PUSCH data symbol sent in the uplink under the LS criterionComprises the following steps:

${\hat{s}}_{\mathrm{symbol},\mathrm{sc}}^{i,\mathrm{data}}={\left[\left({\hat{H}}_{\mathrm{symbol},\mathrm{sc}}^{i,\mathrm{data}}\right){\left(\hat{R}{e}_{n_{\mathrm{RB}}}^{i,\mathrm{Data}\left(\mathrm{new}\right)}\right)}^{-1}{\hat{H}}_{\mathrm{symbol},\mathrm{sc}}^{i,\mathrm{data}}\right]}^{-1}{\left({\hat{H}}_{\mathrm{symbol},\mathrm{sc}}^{i,\mathrm{data}}\right)}^H{\left({\hat{R}e}_{n_{R_B}}^{i,\mathrm{Data}\left(\mathrm{new}\right)}\right)}^{-1}{r}_{\mathrm{symbol},\mathrm{sc}}^{i,\mathrm{data}}$

in the embodiment of the invention, after the frequency domain equalization detection process is finished, the operations of demodulation, descrambling, decoding and the like can be carried out on the signal after the frequency domain equalization detection, so as to obtain the information source bit.

Example two

Based on the same inventive concept as the above method, an embodiment of the present invention further provides a device for frequency domain equalization detection, as shown in fig. 4, the device includes:

a calculating module 11, configured to calculate a noise interference covariance matrix Re _ pilot of the pilot subcarriers;

a determining module 12, configured to determine, by using the noise interference covariance matrix Re _ pilot of the pilot subcarriers, that frequency domain equalization detection is performed by using an interference rejection combining IRC detection method or a maximum ratio combining MRC detection method.

In this embodiment of the present invention, the calculating module 11 is specifically configured to obtain a channel response estimation value H _ pilot by performing channel estimation on a pilot subcarrier, and calculate a noise interference covariance matrix Re _ pilot of the pilot subcarrier by using the channel response estimation value H _ pilot.

In this embodiment of the present invention, the calculating module 11 is further configured to receive a signal according to a pilot subcarrierAnd pilot signals assigned to target usersPerforming channel estimation to obtain channel response estimation value

Wherein, (i, 1) is a target user in an uplink target cell i, and i represents a target cell number, slot represents a time slot number, and sc represents a subcarrier number;

represents the received signal on the sc pilot subcarrier in the slot time slot, which is N_RColumn vector of × 1 dimensions, and N_RRepresenting the number of uplink receiving antennas;

indicates that the target user (i,1) pilot signals on the sc pilot subcarrier in the first slot are scalar;

represents the channel response estimate for the target user (i, 1) on the sc-th pilot subcarrier in the target cell i, slot, and is N_RColumn vectors of dimension × 1.

In this embodiment of the present invention, the calculating module 11 is further configured to calculate, for each pilot subcarrier in each slot, a noise interference covariance matrix of each pilot subcarrier according to the following formula

${\hat{R}e}_{\mathrm{slot},\mathrm{sc}}^{i,\mathrm{pilot}}=E\left[{\left|\right|r_{\mathrm{slot},\mathrm{sc}}^{i,\mathrm{pilot}}-{\hat{H}}_{\mathrm{slot},\mathrm{sc}}^{i,1}{s}_{\mathrm{slot},\mathrm{sc}}^{i,1}\left|\right|}_2^2\right];$

And calculating the noise interference covariance matrix of the averaged pilot subcarriers corresponding to all pilot subcarriers in one physical resource block PRB according to the following formula

${\hat{R}e}_{n_{\mathrm{RB}}}^{i,\mathrm{pilot}}=\frac{1}{N_{\mathrm{sc}}^{\mathrm{RB}}}\underset{\mathrm{sc}=N_{\mathrm{sc}}^{\mathrm{RB}}{n}_{\mathrm{RB}}}{\overset{N_{\mathrm{sc}}^{\mathrm{RB}}(n_{\mathrm{RB}}+1)-1}{\mathrm{\Σ}}}\left({\hat{R}e}_{\mathrm{slot},\mathrm{sc}}^{i,\mathrm{pilot}}\right);$

Wherein, (i, 1) is a target user in an uplink target cell i, and i represents a target cell number, slot represents a time slot number, and sc represents a subcarrier number;

represents the received signal on the sc pilot subcarrier in the slot time slot, which is N_RColumn vector of × 1 dimensions, and N_RRepresenting the number of uplink receiving antennas;

represents the channel response estimate for the target user (i, 1) on the sc-th pilot subcarrier in the target cell i, slot, and is N_RColumn vectors of dimension × 1;

indicating the pilot signal of the sc pilot subcarrier of the target user (i, 1) in the slot-th time slot, and the pilot signal is a scalar;

represents the conjugate transpose of vector A multiplied by A, andE[A]represents the mathematical expectation or average of vector A/matrix A;

representing the number of subcarriers contained in one PRB;

n_RBindicating the number of the current PRB.

In this embodiment of the present invention, the determining module 12 is specifically configured to calculate a noise interference covariance matrix Re _ data of a data subcarrier by using the noise interference covariance matrix Re _ pilot of the pilot subcarrier, and determine to perform frequency domain equalization detection by using an IRC detection method or an MRC detection method by using the noise interference covariance matrix Re _ data of the data subcarrier.

In this embodiment of the present invention, the determining module 12 is further configured to perform time slot interpolation operation on the noise interference covariance matrix Re _ pilot of the pilot subcarrier when there is no frequency hopping within the PUSCH subframe of the physical uplink shared channel, so as to obtain the noise interference covariance matrix Re _ data of the data subcarrier on each SC-FDMA symbol; or,

when there is PUSCH intra-subframe hopping, then for an SC-FDMA symbol within one slot, the noise-interference covariance matrix Re _ data of the data subcarriers on the same band is equal to the noise-interference covariance matrix Re _ pilot of the pilot subcarriers within the slot.

In the embodiment of the present invention, the determining module 12 is specifically configured to calculate a ratio of the noise power to the interference power according to the following formula;

$\mathrm{\η}=\frac{\mathrm{mean}\left(\mathrm{diag}\left(R_e\right)\right)}{\mathrm{mean}\left(\mathrm{abs}(R_e-\mathrm{diag}\left(\mathrm{diag}\left(R_e\right)\right))\right)}-1=\frac{\mathrm{\β}}{\mathrm{\α}}-1$

when the eta is larger than a preset threshold value, performing frequency domain equalization detection on each subcarrier by adopting an IRC detection mode; when the eta is not greater than a preset threshold value, performing frequency domain equalization detection on each subcarrier by adopting an MRC detection mode;

wherein mean represents the average value, diag represents the extraction of diagonal elements, and abs represents the absolute value;

β＝mean(diag(R_e) And it is R)_eThe average of the diagonal elements of the matrix is the average power of the interference and noise;

α＝mean(abs(R_e-diag(diag(R_e) ))) and is R)_eThe average value of the modulus values of the matrix off-diagonal elements is approximate to the interference average power;

when the noise interference covariance matrix Re _ pilot of the pilot frequency subcarrier is used for determining that the frequency domain equalization detection is carried out by adopting an IRC detection mode or an MRC detection mode, then the R_eNoise from pilot subcarriersDetermining an interference covariance matrix Re _ pilot; when the noise interference covariance matrix Re _ data of the data subcarrier is used for determining that the frequency domain equalization detection is carried out by adopting an IRC detection mode or an MRC detection mode, then the R_eDetermined by the noise interference covariance matrix Re data of the data subcarriers.

In this embodiment of the present invention, the determining module 12 utilizes the received signal of the data subcarrier in the process of determining that the frequency domain equalization detection is performed by using the IRC detection method or the MRC detection methodChannel estimation response matrixAnd the noise interference covariance matrix of the updated data subcarriersCarrying out frequency domain equalization detection on each data subcarrier;

wherein, i represents the number of a target cell, SC represents the number of a subcarrier, and symbol represents the number of an SC-FDMA symbol; n is_RBA number representing a current PRB;

represents the received signal on the SC-th pilot sub-carrier on the SC-FDMA symbol of the symbol number and is N_RColumn vectors of dimension × 1.

In this embodiment of the present invention, the determining module 12 is further configured to determine the channel estimation response matrixAnd the channel estimation response matrixThe determination method specifically comprises the following steps:

when there is no PUSCH intra-subframe frequency hopping, pairPerforming interpolation operation between time slots to obtain a channel estimation response matrix of a data subcarrier on each SC-FDMA symbolOr,

when there is PUSCH intra-sub-frame frequency hopping, then for all SC-FDMA symbols within one slot, the channel estimation response matrix for the data sub-carriers on the same bandEqual to pilot sub-carrier in the slot

Wherein,represents the channel response estimate for the target user (i, 1) on the sc-th pilot subcarrier in the target cell i, slot, and is N_RColumn vectors of dimension × 1.

In this embodiment of the present invention, the determining module 12 is further configured to determine the updated noise interference covariance matrix of the data subcarriersAnd the updated noise interference covariance matrix of the data subcarriersThe determination method specifically comprises the following steps:

determining a noise interference covariance matrix of the updated data subcarriers as follows ${\hat{R}e}_{n_{\mathrm{RB}}}^{i,\mathrm{Data}\left(\mathrm{new}\right)};$

${\hat{R}e}_{n_{\mathrm{RB}}}^{i,\mathrm{Data}\left(\mathrm{new}\right)}=A1\×{\hat{R}e}_{n_{\mathrm{RB}}}^{i,\mathrm{Data}}+A2\×I;$

When the frequency domain equalization detection is performed by adopting an IRC detection mode, A1 is 1.0, and A2 is 0.0; when the frequency domain equalization detection is performed by using the MRC detection method, a1 is equal to 0.0,and it isThe average of the diagonal elements of the matrix is the average power of the interference and noise; i denotes an identity matrix.

The modules of the device can be integrated into a whole or can be separately deployed. The modules can be combined into one module, and can also be further split into a plurality of sub-modules.

Through the above description of the embodiments, those skilled in the art will clearly understand that the present invention may be implemented by software plus a necessary general hardware platform, and certainly may also be implemented by hardware, but in many cases, the former is a better embodiment. Based on such understanding, the technical solutions of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute the methods according to the embodiments of the present invention.

Those skilled in the art will appreciate that the drawings are merely schematic representations of one preferred embodiment and that the blocks or flow diagrams in the drawings are not necessarily required to practice the present invention.

Those skilled in the art will appreciate that the modules in the devices in the embodiments may be distributed in the devices in the embodiments according to the description of the embodiments, and may be correspondingly changed in one or more devices different from the embodiments. The modules of the above embodiments may be combined into one module, or further split into multiple sub-modules.

The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.

The above disclosure is only for a few specific embodiments of the present invention, but the present invention is not limited thereto, and any variations that can be made by those skilled in the art are intended to fall within the scope of the present invention.

Claims (18)

1. A method for frequency domain equalization detection, comprising:

calculating a noise interference covariance matrix Re _ pilot of the pilot frequency sub-carrier;

determining to adopt an Interference Rejection Combining (IRC) detection mode or a Maximum Ratio Combining (MRC) detection mode to perform frequency domain equalization detection by using the noise interference covariance matrix Re _ pilot of the pilot frequency subcarrier;

the method for performing frequency domain equalization detection by using the noise interference covariance matrix Re _ pilot of the pilot frequency subcarrier determines to perform frequency domain equalization detection by using an Interference Rejection Combining (IRC) detection mode or a Maximum Ratio Combining (MRC) detection mode, and specifically includes:

and calculating a noise interference covariance matrix Re _ data of the data subcarriers by using the noise interference covariance matrix Re _ pilot of the pilot subcarriers, and determining to adopt an IRC detection mode or an MRC detection mode to carry out frequency domain equalization detection by using the noise interference covariance matrix Re _ data of the data subcarriers.

2. The method of claim 1, wherein the calculating the noise-interference covariance matrix Re _ pilot for the pilot subcarriers comprises:

and obtaining a channel response estimation value H _ pilot by carrying out channel estimation on a pilot frequency subcarrier, and calculating a noise interference covariance matrix Re _ pilot of the pilot frequency subcarrier by using the channel response estimation value H _ pilot.

3. The method of claim 2, wherein the obtaining the channel response estimate H _ pilot by performing channel estimation on the pilot subcarriers comprises:

receiving signal based on pilot frequency subcarrierAnd pilot signals assigned to target usersPerforming channel estimation to obtain channel response estimation value

Wherein, (i, 1) is a target user in an uplink target cell i, and i represents a target cell number, slot represents a time slot number, and sc represents a subcarrier number;

to representWithin the first slot, the receiving signal on the sc pilot subcarrier is N_RColumn vector of × 1 dimensions, and N_RRepresenting the number of uplink receiving antennas;

indicating the pilot signal of the sc pilot subcarrier of the target user (i, 1) in the slot-th time slot, and the pilot signal is a scalar;

represents the channel response estimate for the target user (i, 1) on the sc-th pilot subcarrier in the target cell i, slot, and is N_RColumn vectors of dimension × 1.

4. The method of claim 2, wherein the calculating the noise-interference covariance matrix Re _ pilot of the pilot subcarriers using the channel response estimate H _ pilot comprises:

for each pilot frequency subcarrier in each slot, calculating the noise interference covariance matrix of each pilot frequency subcarrier according to the following formula

$\hat{R}{e}_{\mathrm{slot},\mathrm{sc}}^{i,\mathrm{pilot}}=E\left[{\left|\right|r_{\mathrm{slot},\mathrm{sc}}^{i,\mathrm{pilot}}-{\hat{H}}_{\mathrm{slot},\mathrm{sc}}^{i,1}{s}_{\mathrm{slot},\mathrm{sc}}^{i,1}\left|\right|}_2^2\right];$

And calculating the noise interference covariance matrix of the averaged pilot subcarriers corresponding to all pilot subcarriers in one physical resource block PRB according to the following formula

$\hat{R}{e}_{n_{\mathrm{RB}}}^{i,\mathrm{pilot}}=\frac{1}{N_{\mathrm{sc}}^{\mathrm{RB}}}\underset{\mathrm{sc}=N_{\mathrm{sc}}^{\mathrm{RB}}{n}_{\mathrm{RB}}}{\overset{N_{\mathrm{sc}}^{\mathrm{RB}}(n_{\mathrm{RB}}+1)-1}{\mathrm{\Σ}}}\left(\hat{R}{e}_{\mathrm{slot},\mathrm{sc}}^{i,\mathrm{pilot}}\right);$

Wherein, (i, 1) is a target user in an uplink target cell i, and i represents a target cell number, slot represents a time slot number, and sc represents a subcarrier number;

represents the received signal on the sc pilot subcarrier in the slot time slot, which is N_RColumn vector of × 1 dimensions, and N_RRepresenting the number of uplink receiving antennas;

represents the channel response estimate for the target user (i, 1) on the sc-th pilot subcarrier in the target cell i, slot, and is N_RColumn vectors of dimension × 1;

indicating the pilot signal of the sc pilot subcarrier of the target user (i, 1) in the slot-th time slot, and the pilot signal is a scalar;

represents the conjugate transpose of vector A multiplied by A, andE[A]represents the mathematical expectation or average of vector A/matrix A;

representing the number of subcarriers contained in one PRB;

n_RBindicating the number of the current PRB.

5. The method of claim 1, wherein calculating a noise interference covariance matrix Re _ data for data subcarriers using the noise interference covariance matrix Re _ pilot for the pilot subcarriers comprises:

when no PUSCH (physical uplink shared channel) intra-subframe frequency hopping exists, performing time slot interpolation operation on the noise interference covariance matrix Re _ pilot of the pilot frequency subcarrier to obtain the noise interference covariance matrix Re _ data of the data subcarrier on each single carrier frequency division multiple access (SC-FDMA) symbol; or,

when there is PUSCH intra-subframe hopping, then for all SC-FDMA symbols within one slot, the noise-interference covariance matrix Re _ data of the data subcarriers on the same band is equal to the noise-interference covariance matrix Re _ pilot of the pilot subcarriers within that slot.

6. The method of claim 1, wherein determining the frequency domain equalization detection process using the IRC detection mode or the MRC detection mode specifically includes:

calculating the ratio of the noise power to the interference power according to the following formula;

$\mathrm{\η}=\frac{\mathrm{mean}\left(\mathrm{diag}\left(R_e\right)\right)}{\mathrm{mean}\left(\mathrm{abs}(R_e-\mathrm{diag}\left(\mathrm{diag}\left(R_e\right)\right))\right)}-1=\frac{\mathrm{\β}}{\mathrm{\α}}-1;$

when the eta is larger than a preset threshold value, performing frequency domain equalization detection on each subcarrier by adopting an IRC detection mode; when the eta is not greater than a preset threshold value, performing frequency domain equalization detection on each subcarrier by adopting an MRC detection mode;

wherein mean represents the average value, diag represents the extraction of diagonal elements, and abs represents the absolute value;

β＝mean(diag(R_e) And it is R)_eThe average of the diagonal elements of the matrix is the average power of the interference and noise;

α＝mean(abs(R_e-diag(diag(R_e) ))) and is R)_eThe average value of the modulus values of the matrix off-diagonal elements is approximate to the interference average power;

when the noise interference covariance matrix Re _ pilot of the pilot frequency subcarrier is used for determining that the frequency domain equalization detection is carried out by adopting an IRC detection mode or an MRC detection mode, then the R_eNoise interference covariance matrix Re _ pil by pilot subcarriersDetermining ot; when the noise interference covariance matrix Re _ data of the data subcarrier is used for determining that the frequency domain equalization detection is carried out by adopting an IRC detection mode or an MRC detection mode, then the R_eDetermined by the noise interference covariance matrix Re data of the data subcarriers.

7. The method of claim 1, wherein the frequency domain equalization detection process using IRC detection mode or MRC detection mode further comprises:

receiving signals using data subcarriersChannel estimation response matrixAnd the noise interference covariance matrix of the updated data subcarriersCarrying out frequency domain equalization detection on each data subcarrier;

wherein, i represents the number of a target cell, SC represents the number of a subcarrier, and symbol represents the number of an SC-FDMA symbol; n is_RBA number representing a current PRB;

represents the received signal on the SC-th pilot sub-carrier on the SC-FDMA symbol of the symbol number and is N_RColumn vectors of dimension × 1.

8. The method of claim 7, wherein the channel estimation response matrixThe determination method specifically comprises the following steps:

when there is no PUSCH intra subframe frequency hoppingTo, forPerforming interpolation operation between time slots to obtain a channel estimation response matrix of a data subcarrier on each SC-FDMA symbolOr,

when there is PUSCH intra-sub-frame frequency hopping, then for all SC-FDMA symbols within one slot, the channel estimation response matrix for the data sub-carriers on the same bandEqual to pilot sub-carrier in the slot

Wherein,represents the channel response estimate for the target user (i, 1) on the sc-th pilot subcarrier in the target cell i, slot, and is N_RColumn vectors of dimension × 1.

9. The method of claim 7, wherein the updated noise interference covariance matrix for the data subcarriersThe determination method specifically comprises the following steps:

determining a noise interference covariance matrix of the updated data subcarriers as follows

$\hat{R}{e}_{n_{\mathrm{RB}}}^{i,\mathrm{Data}\left(\mathrm{new}\right)}=A1\×\hat{R}{e}_{n_{\mathrm{RB}}}^{i,\mathrm{Data}}+A2\×I;$

When the frequency domain equalization detection is performed by adopting an IRC detection mode, A1 is 1.0, and A2 is 0.0;

when the frequency domain equalization detection is performed by using the MRC detection method, a1 is equal to 0.0,and it isThe average of the diagonal elements of the matrix is the average power of the interference and noise; i denotes an identity matrix.

10. An apparatus for frequency domain equalization detection, comprising:

the calculation module is used for calculating a noise interference covariance matrix Re _ pilot of the pilot frequency subcarrier;

a determining module, configured to determine, by using the noise interference covariance matrix Re _ pilot of the pilot subcarriers, that frequency domain equalization detection is performed by using an interference rejection combining IRC detection method or a maximum ratio combining MRC detection method;

wherein the determining module is specifically configured to:

and calculating a noise interference covariance matrix Re _ data of the data subcarriers by using the noise interference covariance matrix Re _ pilot of the pilot subcarriers, and determining to adopt an IRC detection mode or an MRC detection mode to carry out frequency domain equalization detection by using the noise interference covariance matrix Re _ data of the data subcarriers.

11. The apparatus of claim 10,

the calculation module is specifically configured to obtain a channel response estimation value H _ pilot by performing channel estimation on a pilot subcarrier, and calculate a noise interference covariance matrix Re _ pilot of the pilot subcarrier by using the channel response estimation value H _ pilot.

12. The apparatus of claim 11,

the calculating module is further used for receiving signals according to the pilot frequency sub-carriersAnd pilot signals assigned to target usersPerforming channel estimation to obtain channel response estimation value

Wherein, (i, 1) is a target user in an uplink target cell i, and i represents a target cell number, slot represents a time slot number, and sc represents a subcarrier number;

represents the received signal on the sc pilot subcarrier in the slot time slot, which is N_RColumn vector of × 1 dimensions, and N_RRepresenting the number of uplink receiving antennas;

indicating the pilot signal of the sc pilot subcarrier of the target user (i, 1) in the slot-th time slot, and the pilot signal is a scalar;

represents the channel response estimate for the target user (i, 1) on the sc-th pilot subcarrier in the target cell i, slot, and is N_RColumn vectors of dimension × 1.

13. The apparatus of claim 11,

the calculating module is further configured to calculate, for each pilot subcarrier in each slot, a noise interference covariance matrix of each pilot subcarrier according to the following formula

$\hat{R}{e}_{\mathrm{slot},\mathrm{sc}}^{i,\mathrm{pilot}}=E\left[{\left|\right|r_{\mathrm{slot},\mathrm{sc}}^{i,\mathrm{pilot}}-{\hat{H}}_{\mathrm{slot},\mathrm{sc}}^{i,1}{s}_{\mathrm{slot},\mathrm{sc}}^{i,1}\left|\right|}_2^2\right];$

And calculating the noise interference covariance matrix of the averaged pilot subcarriers corresponding to all pilot subcarriers in one physical resource block PRB according to the following formula

$\hat{R}{e}_{n_{\mathrm{RB}}}^{i,\mathrm{pilot}}=\frac{1}{N_{\mathrm{sc}}^{\mathrm{RB}}}\underset{\mathrm{sc}=N_{\mathrm{sc}}^{\mathrm{RB}}{n}_{\mathrm{RB}}}{\overset{N_{\mathrm{sc}}^{\mathrm{RB}}(n_{\mathrm{RB}}+1)-1}{\mathrm{\Σ}}}\left(\hat{R}{e}_{\mathrm{slot},\mathrm{sc}}^{i,\mathrm{pilot}}\right);$

Wherein, (i, 1) is a target user in an uplink target cell i, and i represents a target cell number, slot represents a time slot number, and sc represents a subcarrier number;

represents the received signal on the sc pilot subcarrier in the slot time slot, which is N_RColumn vector of × 1 dimensions, and N_RRepresenting the number of uplink receiving antennas;

represents the channel response estimate for the target user (i, 1) on the sc-th pilot subcarrier in the target cell i, slot, and is N_RColumn vectors of dimension × 1;

indicating the pilot signal of the sc pilot subcarrier of the target user (i, 1) in the slot-th time slot, and the pilot signal is a scalar;

represents the conjugate transpose of vector A multiplied by A, andE[A]represents the mathematical expectation or average of vector A/matrix A;

representing the number of subcarriers contained in one PRB;

n_RBindicating the number of the current PRB.

14. The apparatus of claim 10,

the determining module is further configured to perform inter-slot interpolation operation on the noise interference covariance matrix Re _ pilot of the pilot subcarrier to obtain the noise interference covariance matrix Re _ data of the data subcarrier on each single carrier frequency division multiple access SC-FDMA symbol when there is no physical uplink shared channel PUSCH intraframe frequency hopping; or,

when there is PUSCH intra-subframe hopping, then for all SC-FDMA symbols within one slot, the noise-interference covariance matrix Re _ data of the data subcarriers on the same band is equal to the noise-interference covariance matrix Re _ pilot of the pilot subcarriers within that slot.

15. The apparatus of claim 10,

the determining module is specifically configured to calculate a ratio of the noise power to the interference power according to the following formula;

$\mathrm{\η}=\frac{\mathrm{mean}\left(\mathrm{diag}\left(R_e\right)\right)}{\mathrm{mean}\left(\mathrm{abs}(R_e-\mathrm{diag}\left(\mathrm{diag}\left(R_e\right)\right))\right)}-1=\frac{\mathrm{\β}}{\mathrm{\α}}-1;$

when the eta is larger than a preset threshold value, performing frequency domain equalization detection on each subcarrier by adopting an IRC detection mode; when the eta is not greater than a preset threshold value, performing frequency domain equalization detection on each subcarrier by adopting an MRC detection mode;

wherein mean represents the average value, diag represents the extraction of diagonal elements, and abs represents the absolute value;

β＝mean(diag(R_e) And it is R)_eThe average of the diagonal elements of the matrix is the average power of the interference and noise;

α＝mean(abs(R_e-diag(diag(R_e) ))) and is R)_eThe average value of the modulus values of the matrix off-diagonal elements is approximate to the interference average power;

when the noise interference covariance matrix Re _ pilot of the pilot frequency subcarrier is used for determining that the frequency domain equalization detection is carried out by adopting an IRC detection mode or an MRC detection mode, then the R_eDetermining by a noise interference covariance matrix Re _ pilot of the pilot frequency sub-carrier; when the noise interference covariance matrix Re _ data of the data subcarrier is used for determining that the frequency domain equalization detection is carried out by adopting an IRC detection mode or an MRC detection mode, then the R_eDetermined by the noise interference covariance matrix Re data of the data subcarriers.

16. The apparatus of claim 10,

the determining module determines to adopt an IRC detection mode or an MRC detection modeReceiving signal of data subcarrier is utilized in the process of carrying out frequency domain equalization detectionChannel estimation response matrixAnd the noise interference covariance matrix of the updated data subcarriersCarrying out frequency domain equalization detection on each data subcarrier;

wherein, i represents the number of a target cell, SC represents the number of a subcarrier, and symbol represents the number of an SC-FDMA symbol; n is_RBA number representing a current PRB;

represents the received signal on the SC-th pilot sub-carrier on the SC-FDMA symbol of the symbol number and is N_RColumn vectors of dimension × 1.

17. The apparatus of claim 16,

the determining module is further configured to determine the channel estimation response matrixAnd the channel estimation response matrixThe determination method specifically comprises the following steps:

when there is no PUSCH intra-subframe frequency hopping, pairPerforming interpolation operation between time slots to obtain data subcarriers on each SC-FDMA symbolChannel estimation response matrix of waveOr,

when there is PUSCH intra-sub-frame frequency hopping, then for all SC-FDMA symbols within one slot, the channel estimation response matrix for the data sub-carriers on the same bandEqual to pilot sub-carrier in the slot

Wherein,represents the channel response estimate for the target user (i, 1) on the sc-th pilot subcarrier in the target cell i, slot, and is N_RColumn vectors of dimension × 1.

18. The apparatus of claim 16,

the determining module is further configured to determine a noise interference covariance matrix of the updated data subcarriersAnd the updated noise interference covariance matrix of the data subcarriersThe determination method specifically comprises the following steps:

determining a noise interference covariance matrix of the updated data subcarriers as follows

$\hat{R}{e}_{n_{\mathrm{RB}}}^{i,\mathrm{Data}\left(\mathrm{new}\right)}=A1\×\hat{R}{e}_{n_{\mathrm{RB}}}^{i,\mathrm{Data}}+A2\×I;$

When the frequency domain equalization detection is performed by adopting an IRC detection mode, A1 is 1.0, and A2 is 0.0;

when the frequency domain equalization detection is performed by using the MRC detection method, a1 is equal to 0.0,and it isThe average of the diagonal elements of the matrix is the average power of the interference and noise; i denotes an identity matrix.