WO2012034400A1

WO2012034400A1 - Method and apparatus for detecting narrow-band interference in mimo-ofdm system

Info

Publication number: WO2012034400A1
Application number: PCT/CN2011/073533
Authority: WO
Inventors: 周旭武; 韩英杰
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-09-17
Filing date: 2011-04-29
Publication date: 2012-03-22
Also published as: CN102404257B; CN102404257A

Abstract

The invention discloses a method and an apparatus for detecting narrow-band interference in a MIMO-OFDM system. The method includes that: a pilot sub-carrier frequency group comprising two pilot frequencies is selected from each time-frequency unit, and the two pilot frequencies in the pilot frequency sub-carrier group is located at different frequency positions of different OFDM symbols; the sum of the signal power of the pilot frequency sub-carrier group is subtracted from the channel response value of the two sub-carriers in the pilot frequency sub-carrier group to obtain the interference-noise power value of the pilot frequency sub-carrier group according which to determine the interference-noise power value of each sub-carrier in the time-frequency unit. The apparatus includes a module for selecting the pilot frequency sub-carrier group and a module for determining the interference-noise power value. The invention can quite accurately estimate narrow-band interference information and detect the location and power of the narrow-band interference exactly even when the narrow-band interference is weak.

Description

Narrowband interference detection method and device in MIMO-OFDM system

The present invention relates to the field of mobile broadband wireless access, and more particularly to an Orthogonal Frequency Division Multiplexing (OFDM) system for narrowband interference detection in Multiple Input Multiple Output (MIMO) mode. Method and device. Background technique

A new generation of wireless communication systems requires higher transmission rates, and OFDM technology has emerged. It divides the serial data into N different parallel data streams, transmits them in parallel on N carriers, has no interference with each other, greatly improves the transmission rate of the system, and the data stream of each subcarrier has a lower bit rate. , improve the reliability of transmission.

OFDM encodes and modulates the data as frequency domain information, transforms it into the time domain by Inverse Discrete Fourier Transform (IDFT), and transmits it on the channel, and inversely transforms the Fourier transform (Discrete Fourier Transform) at the receiving end. , DFT), obtains the original modulated data after channel transmission.

The channel environment of a wireless communication system is diverse. At this time, the traditional single antenna system may be difficult to perform, and the multi-antenna system can overcome such problems, and the MIMO technology is useful.

For a wireless communication system, if both its transmitting antenna and receiving antenna are multiple, it is a MIMO system that enables each MIMO user by transmitting signals on multiple transmitting antennas and receiving signals on multiple receiving antennas. Performance is improved. From the perspective of the base station, the uplink MIMO needs to be completed by two users, namely, cooperative MIMO, spatial multiplexing (SM), and each user has only one transmitting antenna. At present, the detection algorithms of the MIMO system at the receiving end mainly include: a zero-forcing algorithm (ZF), a minimum mean square error algorithm (MMSE), and a maximum a posteriori probability algorithm (MAP).

The performance of the MAP algorithm in MIMO decoding and channel decoding is particularly outstanding. A more accurate log-likelihood ratio (LRR) can be obtained by using the MAP algorithm.

However, the MIMO-OFDM system will become very fragile under external interference. As shown in Figure 1, it is very difficult to suppress narrow-band interference when the external interference characteristics are unknown. Therefore, accurate detection of narrow-band interference is included, including The detection of interference location and frequency is a prerequisite for narrowband interference cancellation and is necessary to ensure the performance of the MIMO-OFDM system.

The traditional narrowband interference detection method detects narrowband interference by setting a certain threshold. This method is only applicable to environments with strong narrowband interference. The detected power is only the number of narrowband interference power and narrowband interference, and the narrowband cannot be determined. The specific location of the interference, and it is not suitable for environments where the narrowband dry 4 is particularly weak. Summary of the invention

The present invention provides a narrowband interference detection method and apparatus in a MIMO-OFDM system, which is used to solve the problem that the narrowband interference power cannot be accurately detected when the narrowband interference is weak in the prior art.

The technical solution of the present invention includes:

The present invention provides a narrowband interference detection method in a MIMO-OFDM system, the method comprising:

Selecting, in each time-frequency unit, a pilot sub-carrier group consisting of two pilots, where two pilots in the pilot sub-carrier group are at different frequency positions of different orthogonal frequency division multiplexing symbols;

And subtracting, from the channel response value of the two subcarriers in the pilot subcarrier group, a signal power sum of the pilot subcarrier group, to obtain an interference noise power value of the pilot subcarrier group, according to the interference noise power. The value determines an interference noise power value for each subcarrier in the time-frequency unit.

Further, the interference noise power value of each subcarrier in the time-frequency unit is an interference noise power value of one pilot in the pilot sub-carrier group, and the calculation method is that the pilot sub-carrier group is dry. The noise power value is divided by two.

After the interference noise power value of each subcarrier in the time-frequency unit is determined, the method further includes:

The physical position of each subcarrier on each orthogonal frequency division multiplexing symbol is determined and recorded according to the subcarrier mapping relationship.

Further, after the recording, the method further includes:

And performing smoothing processing on different orthogonal frequency division multiplexing symbols in the time-frequency unit, and updating an interference noise power value of each subcarrier of the current orthogonal frequency division multiplexing symbol to a previous orthogonal frequency division multiplexing symbol Part of the information of the interference noise power value of the subcarriers of the same physical location, the specific formula is:

Where σ is the interference noise power value of the subcarrier of the current orthogonal frequency division multiplexing symbol, and σ _η ² _{ΙΛ ΙΛ} is the interference noise power value of the same physical position subcarrier of the previous orthogonal frequency division multiplexing symbol, Smoothing factor.

Further, the value of the smoothing coefficient is 0.618.

Further, after the updating, the method further includes:

Performing an arithmetic average of the interference noise power values of the same subcarriers in the plurality of antennas to determine an interference noise power combination value of each subcarrier;

It is determined whether the interference noise power combination value of each subcarrier exceeds the set interference noise power threshold, and if so, it is determined that the subcarrier at the physical location is interfered.

Further, the set interference noise power threshold is a noise variance value, and Κ is an integer.

Further, after the determining that the subcarriers in the physical location are interfered, the method further includes:

The signal to interference plus noise ratio of each subcarrier is determined by using the combined value of the interference noise power of each subcarrier, and is multiplied by the log likelihood ratio calculated by the demodulator as a weight, and the multiplication result is obtained. It is sent to the decoder for narrowband interference cancellation.

Further, before the selecting a pilot subcarrier group consisting of two pilots in each time-frequency unit, the method further includes:

The time domain signal received by the receiving end is converted into a frequency domain signal, and the channel response of each subcarrier in the frequency domain signal in the frequency domain is obtained.

A narrowband interference detecting apparatus in a MIMO-OFDM system, the apparatus comprising: a pilot subcarrier group selecting module, configured to select, in each time-frequency unit, a pilot subcarrier group composed of two pilots, The two pilots in the pilot subcarrier group are at different frequency positions of different orthogonal frequency division multiplexing symbols;

An interference noise power value determining module, configured to subtract a signal power value of the pilot subcarrier group from a channel response value of two subcarriers in the pilot subcarrier group, to obtain interference noise of the pilot subcarrier group a power value, determining an interference noise power value of each subcarrier in the time-frequency unit according to the interference noise power value.

Further, the device further includes:

a physical location determining module, configured to determine, according to a subcarrier mapping relationship, a physical location of each subcarrier on each orthogonal frequency division multiplexing symbol and record;

a smoothing processing module, configured to perform smoothing processing on different orthogonal frequency division multiplexing symbols in the time-frequency unit, and update an interference noise power value of each subcarrier of the current orthogonal frequency division multiplexing symbol to a previous orthogonal Partial information of interference noise power values of subcarriers of the same physical location of the frequency division multiplexed symbols;

An interference noise combining module is configured to perform arithmetic averaging on interference noise power values of the same subcarriers in the plurality of antennas, and determine an interference noise power combined value of each subcarrier;

The determining module is configured to determine whether the interference noise power combined value of each subcarrier exceeds the set interference noise power threshold, and if yes, determine that the subcarrier at the physical location is interfered.

Further, the device further includes: The interference cancellation module is configured to determine a signal to interference plus noise ratio of each subcarrier by using an interference noise power combination value of each subcarrier, and multiply the weight ratio by a logarithm likelihood ratio calculated by the demodulator. The multiplication result is sent to the decoder for narrowband interference cancellation.

The beneficial effects of the present invention are as follows:

The technical solution of the present invention uses the pilot subcarrier group formed by the pilot signal to estimate the noise interference power, and can accurately estimate the narrowband interference information, and can narrow the interference position even when the narrowband interference is weak. The power is detected accurately. Furthermore, by adjusting the SINR _k value of each subcarrier, the metric weight of each received bit is sent to the decoder, and the narrowband interference suppression can be completed. The invention has simple calculation, and the narrow-band interference suppression effect is remarkable, and the performance of the MIMO-OFDM system can be greatly improved. DRAWINGS

Figure 1 is a schematic diagram of the OFDM system being subjected to dryness;

2 is a coding structure diagram of a MIMO-OFDM system;

3 is a flowchart of a method for detecting a narrowband interference in a MIMO-OFDM system according to the present invention; FIG. 4 is a schematic structural diagram of a time-frequency unit according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of estimating a NI power value at different locations by using pilots according to an embodiment of the present invention; FIG. 6 is a structural block diagram of a narrowband interference detecting apparatus in a MIMO-OFDM system according to the present invention;

Figure 7 is an effect diagram A of the present invention;

Fig. 8 is a view showing the effect B of the present invention. detailed description

The present invention is directed to the drawback of the conventional narrowband interference detection method, and proposes a more accurate narrowband interference detection method for the MIMO-OFDM system, which is combined with the MAP algorithm of the receiving end of the MIMO system, even when the narrowband interference is weak. The location of narrowband interference and The power is detected accurately. By performing adaptive narrowband interference suppression by this method, the performance of the MIMO-OFDM system can be greatly improved.

2 is a coding structure diagram of a MIMO-OFDM system. As shown in FIG. 2, the received signal ^ can be expressed as

y _k = h _k x _k + NI _k

Wherein, the first transmitted signal is the channel response in the frequency domain, N _k is the additive white noise, and ^ is the interference, which is the subcarrier number. Combine noise and interference signals, ie NI _k = N _k + I _k .

MIMO-OFDM system decoding uses soft decision decoding. In soft decision decoding, the baseband demodulator calculates the Euclidean distance between each received bit and the possible transmitted bit (0 or 1) as a measure of the soft decision Viterbi decoding.

For simplicity of description, consider that both mobile users (MS) use 16QAM modulation. The 16 points on the constellation are recorded as:

c, c ^2 ' "·' C ^16

The k-th bit records of their corresponding pre-modulation symbols are:

The problem with the prior art is that any k (fc = l, 2, 3, 4) must be calculated

Because of symmetry

16

∑∑ ρ(, _{1 =} ,, ₂ = .,

7=1 C卜b

Where = ς, = c _; .) indicates the prior probability of the modulation symbol group. A reasonable assumption is that this probability is the same for all modulation symbols (1/256), so

For the assumption of Gaussian white noise, it is also assumed that the interference can also be Gaussian white noise when there is interference, so there is σ

Where (σ) is a function of σ, and since it can be approximated in the calculation of the LLR, it is not necessary to give a specific form. Use MAX-LOG approximation

And then do the appropriate simplification can get

Where, the noise plus interference variance of the first symbol

When there is no interference, it is a noise variance, which can be regarded as a constant. When the metric value is calculated, it can be ignored. When there is interference, σ ^ contains the interference power. The o of each subcarrier is not a constant. If it is ignored. This will cause a mismatch in the metrics. When the interference is strong, the degree of mismatch will be very severe, which will greatly reduce the performance.

The optimal decoder, in order to accurately calculate the metric of each received bit, must know the location of the noise power, interference power and interference. In order to achieve a near-optimal decoding effect, the present invention first needs to obtain the above-mentioned necessary information to estimate the information of the unknown interference. And through the interference information, adjust the metric value to achieve the effect of interference suppression.

3 is a flowchart of a method for detecting a narrowband interference in a MIM0-0FDM system according to the present invention. As shown in FIG. 3, the method mainly includes the following steps:

Step 101: Convert a time domain signal received by the receiving end into a frequency domain signal.

Step 102: Acquire a channel response of each subcarrier in the frequency domain in the frequency domain. Step 103: Select, in each time-frequency unit, a pilot subcarrier group consisting of two pilots, and a pilot subcarrier group. The two pilots are at different frequency positions of different OFDM symbols;

Step 104: Subtract the channel power value of the two subcarriers in the pilot subcarrier group from the signal power sum of the pilot subcarrier group to obtain the NI power value of the pilot subcarrier group, and determine each subcarrier in the time-frequency unit. The NI power value of the carrier;

The NI power value of each subcarrier in the time-frequency unit is a NI power value of one pilot in the pilot sub-carrier group, that is, the NI power value of the pilot sub-carrier group is divided by two.

Step 105: Determine, according to a subcarrier mapping relationship, a physical location of each subcarrier on each OFDM symbol and record the physical position of each subcarrier.

Step 106: Perform smoothing processing on different OFDM symbols in the time-frequency unit, and update the NI power value of each subcarrier of the current OFDM symbol to the same physics of the previous OFDM symbol. Partial information of the NI power value of the position subcarrier; the specific formula is

Wherein, the NI power value of the subcarrier of the current OFDM symbol, σ „ ² _^ is the ΝΙ power value of the same physical position subcarrier of the previous OFDM symbol, “is a smoothing coefficient, and can be set according to actual communication conditions.

Step 107: Perform arithmetic average on the NI power values of the same subcarriers in the plurality of antennas, and determine a combined value of the NI power of each subcarrier.

Step 108: Determine whether the combined value of the NI power of each subcarrier exceeds a set NI power threshold, and if yes, determine that the subcarrier at the physical location is interfered;

The set NI power threshold is K times the noise variance value, and K is an integer.

Step 109: Determine, by using the NI power combination value of each subcarrier, the SINR (signal to interference plus noise ratio) of each subcarrier, multiply it as a weight by the LLR calculated by the demodulator, and send the multiplication result. Narrowband interference cancellation is performed in the decoder.

The specific implementation process of the method of the present invention will be further described in detail below by way of an embodiment.

4 is a schematic structural diagram of a time-frequency unit according to an embodiment of the present invention. As shown in FIG. 4, the time-frequency unit is a MIMO time-frequency unit in an 802.16e uplink PUSC mode, and includes a total of 12 subcarriers and 4 pilots. Subcarrier, 8 data subcarriers. The first OFDM symbol and the third OFDM symbol include pilot subcarriers, and all subcarriers in the second OFDM symbol are data subcarriers. P1 and P3 are pilot subcarriers in the first OFDM symbol, P2 and P4 are pilot subcarriers in the third OFDM symbol, P1 and P2 are pilots of user 2, and P3 and P4 are the guides of user 1. Frequency, the remaining subcarriers are data subcarriers.

The specific process of performing narrowband interference detection in the embodiment of the present invention is as follows:

For a single user, there are only 1 pilot in MIMO and only 1 in the subcarrier group, and only two pilots inside one time-frequency unit can be utilized. Taking User 2 as an example, the pilots are P1 and P2. The power of the first subcarrier group is calculated as follows: The total power of u and w is:

The estimated values of the signal power in u and w are:

P _c =2xreal(H _lk -H; _k )

Therefore, the estimated value of the interference plus noise power in _u ^ H _21i is: p ¹ N = p ¹ -p 2

1 C p—

1 p ¹ C

Since the above method is the power sum of 2 pilots on the entire time-frequency unit, to determine the power of each pilot, the average is taken, that is,

For the 8 data subcarriers in the entire time-frequency unit, we consider that the NI value of each data subcarrier is equal to the NI value of the pilot subcarrier, which is also ^/2.

FIG. 5 is a simulation diagram of estimating the power value of NI at different positions by using pilots according to an embodiment of the present invention, as shown in FIG. 5. It can be seen from the simulation diagram that the narrowband interference detection algorithm in the embodiment of the present invention can effectively know the size and specific location of the noise and interference power; only the noise is relatively stable when there is no interference, so only one threshold is needed to intercept the interference. Detected.

After obtaining the NI _k power value of consecutive subcarriers on each OFDM symbol, it is necessary to record the corresponding physical position according to the subcarrier mapping relationship /, and set the corresponding physical position to j, then j = f(k). This completes the interference information acquisition process.

The smoothing of different OFDM symbols can improve the accuracy of the NI estimation to a certain extent, which is more suitable for the changes of the actual communication system. Here, the following smoothing method is used: updating the NI power value of each subcarrier of the current OFDM symbol to the partial information of the NI power value of the same physical position subcarrier of the previous OFDM symbol, and the specific formula is Wherein, the NI power value of the subcarrier of the current OFDM symbol, σ„ ² _^ is the ΝΙ power value of the same physical position subcarrier of the previous OFDM symbol, “is a smoothing coefficient, which can be set according to actual communication conditions, in the simulation In the middle, we take the golden section number ie "= 0.618.

Since in the actual communication system, many receiving antennas are used, the overall performance is improved. After obtaining the NI power value of the subcarriers by using the above steps, the NI power values of the same subcarriers in the multiple antennas are arithmetically averaged, and the NI power combining values of the subcarriers are determined to prepare for subsequent interference suppression. The specific formula is as follows:

Rx

∑

Rx

Where ^ is the number of antennas on the receiving base station side.

Since the pilot uses the NI power value estimation and smoothing, the estimation is more accurate. When there is no interference, the NI power combination value σ ^{2 of} each subcarrier is close to the noise variance. We only need to set the chirp power threshold. It can be several times the noise variance. When the power threshold is exceeded, the interference is considered, otherwise σ ² is the noise floor. The method for detecting interference using the power threshold is as follows:

₂ af _k < threshold

L' ^k [cr _k < f _k ≥ threshold The threshold here is taken as ^: the noise variance is an integer), ie

Threshold = ka _N ²

The decoder needs to use the probability measure such as the LLR probability calculated by the demodulator to decode, and each bit LLR needs a reliability measurement weight. The traditional decoder cannot detect the interference information. The measurement weight S/N under interference is not accurate enough, resulting in performance degradation. By obtaining the interference information, we use the NI power combination value of each subcarrier to determine the SINR _k of each subcarrier, multiply it by the LLR as a weight, and send the multiplication result to the decoder, and finally send it to the decoder. The LLR of the decoder is

LLR = SINR _k x LLR

The decoder uses this information to effectively suppress interference. The SINR weight can measure the reliability of the soft information. The subcarrier with interference has lower SINR, that is, the reliability of soft information is poor. The subcarrier without interference has higher SINR, that is, the reliability of soft information is good. With different weights, the reliability of soft information can be measured, that is, narrowband interference cancellation can be performed by the decoder without other calculations. Therefore, the system performance can be effectively improved without increasing the computational complexity.

Corresponding to the above method of the present invention, the present invention further provides a narrowband interference detecting apparatus in a MIMO-OFDM system, and FIG. 6 is a structural block diagram of a narrowband interference detecting apparatus in the MIMO-OFDM system according to the present invention, as shown in FIG. The device includes:

a pilot subcarrier group selection module 61, configured to select, in each time-frequency unit, a pilot subcarrier group consisting of two pilots, where two pilots in the pilot subcarrier group are in different orthogonal frequencies Dividing the different frequency positions of the multiplexed symbols;

The interference noise power value determining module 62 is configured to subtract the signal power of the pilot subcarrier group from the channel response value of the two subcarriers in the pilot subcarrier group to obtain interference of the pilot subcarrier group. a noise power value, according to which an interference noise power value of each subcarrier in the time-frequency unit is determined, where an NI power value of each data subcarrier in the time-frequency unit is a pilot of the pilot sub-carrier group The NI power value is the NI power value of the pilot subcarrier group divided by two;

a physical location determining module 63, configured to determine, according to a subcarrier mapping relationship, a physical location of each subcarrier on each orthogonal frequency division multiplexing symbol and record;

The smoothing processing module 64 is configured to perform smoothing processing on different orthogonal frequency division multiplexing symbols in the time-frequency unit, and update an interference noise power value of each subcarrier of the current orthogonal frequency division multiplexing symbol to a previous positive Part of the information of the interference noise power value of the same physical position subcarrier of the frequency division multiplexing symbol, the specific formula is Wherein, the NI power value of the subcarrier of the current OFDM symbol, σ „ ² _^ is the ΝΙ power value of the same physical position subcarrier of the previous OFDM symbol, “is a smoothing coefficient, and can be set according to actual communication conditions;

The interference noise combining module 65 is configured to perform arithmetic average on the interference noise power values of the same subcarriers in the plurality of antennas, and determine an interference noise power combined value of each subcarrier;

The determining module 66 is configured to determine whether the interference noise power combined value of each subcarrier exceeds a set interference noise power threshold, and if yes, determine that the subcarrier at the physical location is interfered, wherein the set NI power gate The limit is K times the noise variance value, K is an integer;

The interference cancellation module 67 is configured to determine a signal-to-interference plus noise ratio of each subcarrier by using an interference noise power combination value of each subcarrier, and multiply the weight-to-noise ratio calculated by the demodulator as a weight. The multiplied result is sent to the decoder for narrowband interference cancellation.

The effect of the present invention is as shown in Figs. 7 and 8. In Figs. 7 and 8, the circled curve indicates the case of no interference; the squared curve indicates the interference cancellation; the triangled curve indicates the narrowband interference. Happening. Figure 7 shows the simulation using QPSK modulation, CTC1/2 coding, under one transmit antenna and four receive antennas, through the channel ITU VA60 Km/h, with interference intensity INR=20dB, using the present invention for narrowband interference. After detection and suppression, the performance is close to that without interference, and 8dB is improved compared with the performance when there is interference; Figure 8 is simulated with 16QAM modulation, CTC3/4 coding, under 1 transmit antenna, 4 receive antennas, after The channel ITU VA60 Km/h is performed under the interference intensity INR=20dB. After the narrowband interference detection and suppression by the present invention, the performance is close to that without interference, and is improved by nearly 8 dB compared with the performance when there is interference. As can be seen from Figs. 7 and 8, the present invention is robust and can effectively suppress narrowband interference, and performance is not lost even in the absence of narrowband interference.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included. Within the scope of protection of the present invention.

Claims

Claim

A narrowband interference detection method in a MIMO-OFDM system, the method comprising:

The method according to claim 1, wherein the interference noise power value of each subcarrier in the time-frequency unit is an interference noise power value of one pilot in the pilot subcarrier group; The noise power value is calculated by dividing the interference noise power value of the pilot subcarrier group by two.

The method according to claim 1, wherein after the determining the interference noise power value of each subcarrier in the time-frequency unit, the method further includes:

The method according to claim 3, wherein after the recording, the method further comprises:

And performing smoothing processing on different orthogonal frequency division multiplexing symbols in the time-frequency unit, and updating an interference noise power value of each subcarrier of the current orthogonal frequency division multiplexing symbol to a previous orthogonal frequency division multiplexing symbol The information of the interference noise power value of the subcarriers of the same physical location, the specific formula is:

Wherein, the interference noise power value of the subcarrier of the current orthogonal frequency division multiplexing symbol, σ _η ² _{Ι Ι} is the interference noise power value of the same physical position subcarrier of the previous orthogonal frequency division multiplexing symbol, "for smoothing coefficient.

The method according to claim 4, wherein the smoothing coefficient has a value of 0.618.

The method according to claim 4, wherein after the updating, the method further comprises:

It is determined whether the interference noise power combined value of each subcarrier exceeds the set interference noise power threshold, and when it exceeds, it is determined that the subcarrier at the physical location is interfered.

The method according to claim 6, wherein the set interference noise power threshold is K times the noise variance value, and K is an integer.

The method according to claim 6, wherein after the determining that the subcarriers in the physical location are interfered, the method further includes:

The signal-to-interference plus noise ratio of each subcarrier is determined by using the combined value of the interference noise power of each subcarrier, and is multiplied by the logarithm likelihood ratio calculated by the demodulator as a weight, and the multiplied result is sent to the translation. Narrowband interference cancellation is performed in the coder.

The method according to claim 1, wherein the method further includes: before selecting a pilot subcarrier group consisting of two pilots in each time-frequency unit, the method further includes:

10. A narrowband interference detecting apparatus in a MIMO-OFDM system, the apparatus comprising:

a pilot subcarrier group selection module, configured to select, in each time-frequency unit, a pilot subcarrier group consisting of two pilots, where two pilots in the pilot subcarrier group are in different orthogonal frequency divisions Multiple frequency locations of the multiplexed symbols;

An interference noise power value determining module, configured to use two subcarriers in the pilot subcarrier group A channel response value is subtracted from a signal power sum of the pilot subcarrier group, an interference noise power value of the pilot subcarrier group is obtained, and each subcarrier in the time-frequency unit is determined according to the interference noise power value. Interference noise power value.

The device according to claim 10, wherein the device further comprises: a physical location determining module, configured to determine, according to the subcarrier mapping relationship, each subcarrier on each orthogonal frequency division multiplexing symbol Physical location and record;

The device according to claim 11, wherein the device further comprises: an interference cancellation module, configured to determine, by using an interference noise power combination value of each subcarrier, a signal to interference plus noise ratio of each subcarrier, It is multiplied as a weight to the log likelihood ratio calculated by the demodulator, and the multiplied result is sent to the decoder for narrowband interference cancellation.