KR101443514B1 - Method for cenceling out coexistence interference in wireless communication device and apparatus thereof - Google Patents

Abstract

The present invention relates to a method for canceling out coexistence interference in a wireless communication device and an apparatus thereof. The present invention provides a method for canceling out coexistence interference between a first communication module and a second communication module in a wireless communication device. The method comprises the steps of: estimating a channel coefficient between a first antenna and a second antenna connected to the first communication module and the second communication module, respectively; generating a compensation signal by applying an inverse channel coefficient that is an inverse value of the estimated channel coefficient, to a transmission signal transmitted through the first antenna; and canceling out the interference of a reception signal received through the second antenna by adding the compensation signal to the reception signal. The method for canceling out coexistence interference in a wireless communication device and the apparatus thereof can effectively cancel out coexistence interference by using channel information between transmission and reception antennas when a plurality of communication modules using the same communication band coexist in a wireless communication device.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method and apparatus for coexistence interference in a wireless communication device,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coexistence interference cancellation method and apparatus in a wireless communication device, and more particularly, to a coexistence interference cancellation method in a wireless communication device capable of eliminating mutual coexistence interference And a method for removing the same.

Generally, when there are a plurality of individual wireless communications using the same frequency band in a wireless terminal, mutual interference occurs. Such interference is a factor of deteriorating the wireless communication performance.

As a method for solving this problem, in the related art, interference is avoided by using a frequency division multiplex (FDM) scheme using different frequencies for each wireless protocol or a time division multiplexer (TDM) scheme using time division. However, FDM is not efficient in terms of frequency resources, and TDM has a problem of causing performance degradation.

The technology of the background of the present invention is disclosed in Korean Patent Laid-Open No. 10-2012-0080511.

An object of the present invention is to provide a coexistence interference cancellation method and apparatus in a wireless communication device capable of eliminating mutual coexistence interference when a plurality of wireless communication modules exist in a wireless communication device.

The present invention provides a method for eliminating coexistence interference between a first communication module and a second communication module in a wireless communication device, comprising the steps of: estimating a channel coefficient between first and second antennas connected to the first and second communication modules; , Generating a compensation signal by applying an inverse channel coefficient that is an inverse value of the estimated channel coefficient to a transmission signal transmitted through the first antenna, and adding the compensation signal to the reception signal received through the second antenna And removing the interference of the received signal.

The step of estimating a channel coefficient between the first and second antennas may include extracting a center frequency of a test signal transmitted through the first antenna, A step of setting the size of the test signal output from the first antenna and received by the second antenna from zero to a time point corresponding to an inverse number of the center frequency, And selecting, as the time delay value for the channel coefficient to be estimated, a time point at which the size of the received test signal becomes the smallest within the time period.

The step of estimating a channel coefficient between the first and second antennas may include the steps of monitoring the magnitude of the test signal received by the second antenna while varying the gain information within a certain size interval, The method may further include the step of selecting, as gain information for the channel coefficient to be estimated, a gain value in which the size of the test signal received by the second antenna is the smallest within the size interval.

The compensation signal is a signal obtained by multiplying a transmission signal x (t) transmitted through the first antenna by an inverse channel coefficient -H (x) which is an inverse value of the estimated channel coefficient H (x) ) * H (t), which can be defined by the following equation.

-x (t) * H (t) = -? x (t? t)

Here,? Represents the selected gain information and? T represents the selected time delay value.

Also, the first and second communication modules may use the same ISM band (Industrial Scientific Medical Band).

Also, the first antenna may be a transmitting antenna, and the second antenna may be a receiving antenna.

The present invention provides an apparatus for canceling interference between first and second communication modules in a wireless communication device, the apparatus comprising: a channel estimating unit that estimates channel coefficients between first and second antennas connected to the first and second communication modules, An inverse channel generation unit for generating a compensation signal by applying an inverse channel coefficient which is an inverse value of the estimated channel coefficient to a transmission signal transmitted through the first antenna, And a summing unit for adding the compensation signal to the signal to remove the interference of the reception signal.

Here, the channel coefficient estimator may include a center frequency extractor for extracting a center frequency of a test signal transmitted through the first antenna, and a controller for calculating a time delay information and gain information for the channel coefficient to be estimated, A first signal size monitoring unit for measuring a size of a test signal output from the first antenna and received by the second antenna for a time from 0 to a time point corresponding to an inverse number of the center frequency; And a time delay information selector for selecting a time point at which the size of the received test signal becomes the smallest within the time as a time delay value for the channel coefficient to be estimated.

In addition, the channel coefficient estimator may include a second signal size monitor for monitoring the magnitude of the test signal received by the second antenna while varying the gain information within an arbitrary size interval, And a gain information selection unit that selects a gain value that minimizes the size of the received test signal as gain information for the channel coefficient to be estimated.

Here, the transmission signal output through the first or second communication module is transmitted to the first antenna through the channel coefficient estimator, and the reception signal input through the second antenna is transmitted to the first or second communication module Lt; / RTI >

According to the coexistence interference cancellation method and apparatus of the present invention, when a plurality of communication modules using the same communication band coexist in a wireless communication device, coexistence interference can be effectively There is an advantage that can be removed.

1 is a configuration diagram of a coexistence interference cancellation device in a wireless communication device according to an embodiment of the present invention.
2 is a flowchart of a coexistence interference cancellation method using FIG.
FIG. 3 shows an equivalent circuit for the channel coefficients between two antennas in step S210 of FIG.
FIG. 4 shows a concept of eliminating interference using the channel coefficient estimated in step S210 of FIG.
5 is a configuration diagram of the channel coefficient estimating unit of FIG.
FIG. 6 and FIG. 7 show a channel coefficient estimation method using FIG.
FIG. 8 shows an example of estimating a channel coefficient using FIG. 6 and FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

1 is a configuration diagram of a coexistence interference cancellation device in a wireless communication device according to an embodiment of the present invention. The wireless communication device shown in FIG. 1, that is, the wireless terminal includes a plurality of communication modules using the same communication band.

The first communication module 10 and the second communication module 20 may correspond to a communication module using the same ISM band (Industrial Scientific Medical Band). For example, the first communication module 10 and the second communication module may be different modules (Bluetooth module, WiFi module), and both communication modules 10 and 20 may be composed of the same module. There are various modifications of the configuration example of such a communication module.

Here, the first communication module 10 and the second communication module 20 are not necessarily limited to modules using a wireless protocol using the ISM band. That is, the present invention is applicable to various frequency bands.

The first antenna 30 and the second antenna 40 are connected to the first communication module 10 and the second communication module 20. Here, the first antenna 30 corresponds to the transmitting antenna and the second antenna 40 corresponds to the receiving antenna. In this case, each of the communication modules 10 and 20 performs the transmission of the signal through the first antenna 30 and the reception of the signal via the second antenna 40. [

Generally, the communication modules built in the small wireless terminal are installed at a distance from each other, so that there are many cases in which isolation of signals is insufficient. In this case, communication efficiency is lowered due to coexistence interference between signals.

1, the coexistence interference elimination apparatus 100 according to the present embodiment is for eliminating interference problems between coexisting communication modules in a wireless terminal, and includes a channel coefficient estimator 110, an inverse channel generator 120 ), And a summer 130. FIG.

The channel coefficient estimator 110 estimates a channel coefficient between the first antenna 30 and the second antenna 40 connected to the first communication module 10 and the second communication module 20.

The inverse channel generation unit 120 generates a compensation signal by applying an inverse channel coefficient, which is an inverse value of the estimated channel coefficient, to the transmission signal transmitted through the first antenna 30. [

The adder 130 adds the compensation signal to the reception signal received through the second antenna 40 to remove the interference of the reception signal. That is, at the receiving end, the influence of the interference due to the transmission signal flowing into the second antenna 40 is canceled by the compensation signal. Accordingly, a mutual interference problem caused by a plurality of wireless communication modules coexisting in the wireless terminal can be solved.

Meanwhile, in this embodiment, the transmission signal output through the first communication module 10 or the second communication module 20 is transmitted to the first antenna 30 through the channel coefficient estimator 110. [ That is, the first antenna 30 serves as a transmitting antenna in the wireless terminal. A received signal input through the second antenna 40 is transmitted to the first communication module 10 or the second communication module 20. That is, the second antenna 40 serves as a receiving antenna in the wireless terminal.

The channel coefficient estimator 110 may perform a role of an arbiter for controlling the signal flow according to the transmission / reception state of the communication module as well as the estimation of the channel coefficient. For example, if both the communication modules 10 and 20 perform the transmission operation, the time division is performed by the TDM method, and the signals of the communication modules 10 and 230 are sequentially transmitted to the first antenna 30 (transmission antenna) send.

As another example, when one of the two communication modules 10 and 20 performs a transmission operation and the remaining communication modules perform a reception operation, the frequency division is performed by the FDM method to perform transmission and reception operations. However, since the transmission operation through the first antenna 30 (transmission antenna) and the reception operation through the second antenna 40 (reception antenna) are simultaneously performed, the channel coefficient estimation and inversion It is necessary to remove the interference signal through channel generation.

2 is a flowchart of a coexistence interference cancellation method using FIG. Hereinafter, a coexistence interference cancellation method in a wireless communication device according to an embodiment of the present invention will be described.

First, the channel coefficient estimator 110 estimates a channel coefficient between the first antenna 30 and the second antenna 40 (S210).

FIG. 3 shows an equivalent circuit for the channel coefficients between two antennas in step S210 of FIG. Generally, the factors determining the channel characteristics are time delay information and gain information. The channel coefficient H (t) formed between the first antenna 30 and the second antenna 40 in the present embodiment has a concept including time delay information? T and gain information?.

If the transmission signal transmitted through the first antenna 30 is x (t), H (t) satisfying the following Equation 1 can be defined as a channel coefficient between the two antennas 30 and 40 have.

FIG. 4 shows a concept of eliminating interference using the channel coefficient estimated in step S210 of FIG. The transmitted signal x (t) transmitted through the first antenna 30 is converted to x (t) * H (t) while passing through the channel between the first and second antennas 30 and 40. However, this signal may flow through the second antenna 40 again and act as an interference signal.

Here, if a signal transmitted from the first antenna 30 corresponding to the transmitting terminal flows into the second antenna 40 corresponding to the receiving terminal, the receiving terminal acts as an interference signal, so it must be canceled. That is, since the signal x (t) * H (t) flowing into the second antenna 40 corresponds to the interference signal, the value of -x (t) * H (t) . ≪ / RTI > This can be summarized as Equation (2).

Here, -x (t) * H (t) corresponds to -α x (t-Δt) in FIG. This can be derived from Equation (1).

In this embodiment, the time delay information? T and the gain information? Constituting the channel coefficient H (t) between the two antennas 30 and 40 are first obtained and then the value of -H (t) do. The -H (t) value corresponds to an inverse channel coefficient used to eliminate mutual interference between wireless communication modules.

Hereinafter, a process of estimating the channel coefficient H (t) will be described. 5 is a configuration diagram of the channel coefficient estimating unit of FIG. The channel coefficient estimating unit 110 includes a center frequency extracting unit 111, an initial channel coefficient setting unit 112, a first signal size monitoring unit 113, a time delay information selecting unit 114, (115), and gain information selection unit (116).

In the present embodiment, the estimation of the channel coefficient corresponds to a calibration process performed before a signal transmission / reception operation is actually performed. Therefore, a test signal transmitted from a transmitting terminal is used to estimate a channel coefficient, not an actual transmission / reception signal. Of course, a test signal and a signal of the same or similar type as the actual transmit / receive signal may be used.

FIG. 6 and FIG. 7 show a channel coefficient estimation method using FIG. FIG. 6 shows a method of estimating a time delay value from two pieces of information constituting the channel coefficient.

In order to estimate the time delay value, the center frequency extraction unit 111 first extracts the center frequency f _center of the test signal transmitted through the first antenna 30 (S610).

Next, the initial channel coefficient setting unit 112 sets the time delay information and the gain information for the channel coefficient H (x) to be estimated to 0 and an arbitrary value, respectively (S620). That is, Δt = 0 for setting the initial channel coefficient, and α = is set to an arbitrary value. In the process of estimating the time delay value, any value may be used.

Thereafter, the first signal size monitoring unit 113 checks the size of the test signal output from the first antenna 30 and received by the second antenna 40 (S630). The test signal outputted from the first antenna 30 and received by the second antenna 40 means a signal according to the signal path A in FIG. Here, the process of checking the size of the test signal received by the second antenna 40 over time is repeated from 0 to the time point corresponding to the reciprocal of the center frequency (S640 to S650).

Then, the time delay information selection unit 114 selects, as the time delay value? T for the channel coefficient H (x) to be estimated, the time at which the size of the received test signal becomes the smallest within the time period (S660 ).

FIG. 7 shows a method of estimating a gain value from two pieces of information constituting the channel coefficient. alpha is a value between 0 and 1, and the initial channel coefficient setting unit 112 sets a range of a minimum value (ex, 0.1) to be used for gain value estimation (S710).

Next, the second signal size monitoring unit 115 checks the size of the test signal output from the first antenna 30 and received by the second antenna 40 (S720). Here, the process of checking the size of the test signal received by the second antenna 40 according to? Is repeated while varying the gain information within a predetermined size range (ex, 0.1 to 0.9) (S730 ~ S740).

Thereafter, the gain information selection unit 116 selects a gain value that minimizes the size of the test signal received by the second antenna 40 within the arbitrary-size interval, with respect to the channel coefficient H (x) to be estimated And selects the gain information value alpha (S750).

FIG. 8 shows an example of estimating a channel coefficient using FIG. 6 and FIG. 8A is a graph showing the relationship between the magnitude of the test signal output from the first antenna 30 and received by the second antenna 40 for t = 0 to 1 / f _center time interval at step S660 of FIG. (Time point t1 corresponding to point A) as the time delay value for the channel coefficient H (x) to be estimated. 8 (b) is a graph showing the gain of a test signal output from the first antenna 30 and having a minimum size of a test signal received by the second antenna 40, for a period of? = 0.1 to 0.9 in step S750 of FIG. (Gain value corresponding to point B;? 1 value) is selected as a gain value for the channel coefficient H (x) to be estimated.

After the channel coefficient between the two antennas 30 and 40 is estimated as described above, the transmission signal of the transmitter is transmitted through the first antenna 30 and then received by the second antenna 40, The interference signal can easily be canceled by adding the compensation signal to which the value of -H (x) is applied to the signal, to the receiving end.

That is, after the channel coefficient is estimated through the above process, the inverse channel generation unit 120 adds the estimated channel coefficient H (x) to the transmission signal x (t) transmitted through the first antenna 30 The inverse channel coefficient -H (x), which is an inverse value, is applied to generate a compensation signal (S220).

At this time, the inverse channel generation unit 120 divides the transmission signal x (t) from the distributor 140 of FIG. 2 and outputs the inverse value -H (x) of the channel coefficient obtained by the channel coefficient estimation unit 110 And multiplies the distributed transmission signal x (t) to generate a compensation signal.

The compensation signal is defined as -x (t) * H (t), which is a signal obtained by multiplying the transmission signal x (t) by the inverse channel coefficient -H (x)

In Equation (3),? Represents the gain information selected in step S750 and? T represents the time delay value selected in step S660.

The transmission signal transmitted to the outside through the first antenna 30 corresponds to a signal that has passed through the isolator 150 in advance. The isolator 150 is a means for preventing the inflow of external noise and for guiding the signal flow in one direction. As described above, the transmission signal transmitted through the first antenna 30 is reintroduced into the second antenna 40 and acts as an interference signal.

At this time, the adder 130 adds the compensation signal to the reception signal received through the second antenna 40 to remove the interference of the reception signal (S230). Therefore, at the receiving end, the influence of the interference due to the transmission signal transmitted through the second antenna 40 can be canceled by the compensation signal.

As described above, according to the coexistence interference cancellation method and apparatus in the wireless communication device according to the present invention, when a plurality of communication modules using the same communication band coexist in the wireless communication device, There is an advantage that coexistence interference can be effectively removed.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

10: first communication module 20: second communication module
30: first antenna 40: second antenna
100: coexistence interference cancellation device in a wireless communication device
110: channel coefficient estimating unit 111: center frequency extracting unit
112: initial channel coefficient setting unit 113: first signal size monitoring unit
114: time delay information selection unit 115: second signal size monitoring unit
116: Gain information selection unit 120: Inverse channel generation unit
130: adder 140: distributor
150: Isolator

Claims (13)

A method for eliminating coexistence interference between first and second communication modules in a wireless communication device,
Estimating a channel coefficient between the first and second antennas connected to the first and second communication modules;
Generating a compensation signal by applying an inverse channel coefficient, which is an inverse value of the estimated channel coefficient, to a transmission signal transmitted through the first antenna; And
And removing the interference of the received signal by summing the compensation signal with the reception signal received through the second antenna,
Wherein estimating channel coefficients between the first and second antennas comprises:
Extracting a center frequency of a test signal transmitted through the first antenna;
Setting time delay information and gain information for the channel coefficient to be estimated to 0 and an arbitrary value, respectively;
Checking a magnitude of a test signal output from the first antenna and received by the second antenna for a time from 0 to a time point corresponding to an inverse number of the center frequency; And
And selecting a time point at which the size of the received test signal becomes the smallest within the time as a time delay value for the channel coefficient to be estimated. delete The method according to claim 1,
Wherein estimating channel coefficients between the first and second antennas comprises:
Monitoring the magnitude of the test signal received by the second antenna while varying the gain information within an arbitrary magnitude interval; And
Further comprising the step of selecting, as gain information for the channel coefficient to be estimated, a gain value in which the magnitude of the test signal received by the second antenna is the smallest within the arbitrary-size interval, Way. The method of claim 3,
The compensation signal may comprise:
(T) * H (t) obtained by multiplying the transmission signal x (t) transmitted through the first antenna by the inverse channel coefficient -H (x) which is an inverse value of the estimated channel coefficient H , Coexistence interference cancellation method in a wireless communication device defined by the following equation:
-x (t) * H (t) = -? x (t? t)
Here,? Represents the selected gain information and? T represents the selected time delay value. The method according to claim 1,
Wherein the first and second communication modules comprise:
A method for removing coexistence interference in a wireless communication device using the same ISM band (Industrial Scientific Medical Band). The method according to claim 1,
Wherein the first antenna is a transmitting antenna and the second antenna is a receiving antenna. An apparatus for canceling interference between first and second communication modules in a wireless communication device,
A channel coefficient estimator for estimating a channel coefficient between first and second antennas connected to the first and second communication modules;
An inverse channel generator for generating a compensation signal by applying an inverse channel coefficient, which is an inverse value of the estimated channel coefficient, to a transmission signal transmitted through the first antenna; And
And a summer for summing the compensation signal to the received signal received through the second antenna to remove the interference of the received signal,
Wherein the channel coefficient estimator comprises:
A center frequency extracting unit for extracting a center frequency of a test signal transmitted through the first antenna;
An initial channel coefficient setting unit for setting time delay information and gain information for the channel coefficient to be estimated to 0 and an arbitrary value, respectively;
A first signal size monitoring unit for checking a size of a test signal output from the first antenna and received by the second antenna for a time from 0 to a time point corresponding to an inverse number of the center frequency; And
And a time delay information selector for selecting a time point at which the size of the received test signal becomes the smallest within the time as a time delay value for the channel coefficient to be estimated. delete The method of claim 7,
Wherein the channel coefficient estimator comprises:
A second signal size monitoring unit for monitoring the size of the test signal received by the second antenna while varying the gain information within an arbitrary size interval; And
Further comprising a gain information selection unit for selecting, as the gain information for the channel coefficient to be estimated, a gain value in which the size of the received test signal is the smallest within the arbitrary size interval. The method of claim 9,
The compensation signal may comprise:
(T) * H (t) obtained by multiplying the transmission signal x (t) transmitted through the first antenna by the inverse channel coefficient -H (x), which is an inverse value of the estimated channel coefficient H , The coexistence interference canceling device in a wireless communication device defined by the following equation:
-x (t) * H (t) = -? x (t? t)
Here,? Represents the selected gain information and? T represents the selected time delay value. The method of claim 7,
Wherein the first and second communication modules comprise:
A coexistence interference cancellation device in a wireless communication device using the same ISM band (Industrial Scientific Medical Band). The method of claim 7,
Wherein the first antenna is a transmitting antenna and the second antenna is a receiving antenna. The method of claim 7,
The transmission signal output through the first or second communication module is transmitted to the first antenna through the channel coefficient estimator and the received signal input through the second antenna is transmitted to the first or second communication module A coexistence interference cancellation device in a wireless communication device.

Images