CN1725675A - Method for monitoring electromagnetic environment of radio communication system using intelligent antenna - Google Patents

Abstract

A method for monitoring electromagnetic environment of radio communication system includes selecting any idle code channel at base station, using base band signal processing unit to calculate up link beam shape matrix and power of idle code channel, judging whether there is disturbance to electromagnetic environment of the radio system or not according to above calculated out results and then positioning interference signal if there is disturbance.

Description

The method of the electromagnetic environment of the wireless telecommunication system of monitoring use smart antenna

Technical field

The present invention relates to the method for the electromagnetic environment of a kind of monitoring wireless system, especially use the method for the electromagnetic environment of monitoring wireless system in the wireless communication system of smart antenna.

Background technology

Wireless communication system is by radio wave transmissions information, and the electromagnetic environment of wireless communication system is very complicated, various noises are arranged and disturb and exist, in order to guarantee that wireless communication system can operate as normal, in the network planning and network operation process, all need the electromagnetic environment of monitoring wireless system works.Existing wireless system mainly uses the electromagnetic environment around the monitoring of directional antenna and disturbed test instrument, determines the roughly direction of interference by directional antenna, and this monitoring method mainly contains following problem:

(1) the monitoring difficulty is big

At first be to need to use to cost an arm and a leg and heavy disturbed test instrument, secondly test needs often to go up roof or eminence, and Jian Ce difficulty is bigger like this, and can not realize monitoring in real time.

(2) application is restricted

The disturbed test instrument is monitored the power of signal in a certain frequency band by the method for frequency sweep, and this monitoring method can be restricted when being used to use the wireless telecommunication system of smart antenna.Because frequency division multiplexing (FDD) system uses smart antenna to have any problem, use fewer, so the common wireless communication system that uses smart antenna is time division multiplexing (TDD) system.But to the TDD system, because the TDD up-downgoing is with frequently, and the disturbed test instrument can not be distinguished the up-downgoing of TDD system, what just can't distinguish also that frequency sweep obtains is transmitting or interference signal of system self, in order to distinguish, must monitor wireless system self Close All again, to the commercial wireless system of major part, this is unlikely thing.

So the disturbed test instrument should not be monitored the wireless telecommunication system of common use smart antenna.

Used in the wireless telecommunication system of intelligent antenna technology, utilize antenna array and baseband digital signal treatment technology, the reception and the launching beam of base station carried out adaptive figuration, can reduce intrasystem interference greatly, improve power system capacity, reduce transmitted power level and improve receiving sensitivity.

If i receiver is output as ri (n) constantly at n, handle by despreading and digital signal corresponding the base station, obtains the received signal Xj (n) of j code channel (user), is expressed as

$X_j\left(n\right)=\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}{r}_{\mathrm{ij}}\left(n\right)\·w_{\mathrm{ij}}\left(n\right)$

W wherein _Ij(n) be i the receiver uplink beam figuration matrix that n receives constantly on j code channel; r _Ij(n) be i the receiver signal that n exports constantly on j code channel.

For the signal of internal system user emission, the base station can obtain this user's uplink beam figuration matrix on the code channel that the user uses, and this uplink beam figuration matrix has characterized this user's azimuth information; And at idle code channel or idle time slot, the base station can obtain the uplink beam figuration matrix of idle code channel noise and interference, and this uplink beam figuration matrix has characterized the azimuth information of noise and interference.Disturb the direction of propagation of uplink beam figuration matrix characterization signal, interference signal is propagated also its directivity, therefore the base station utilizes smart antenna can detect user's direction, and the while also may be detected the direction of propagation of interference signal, reaches the purpose of interference source orientation then.

Summary of the invention

Method of the present invention is that a kind of method of monitoring electromagnetic environment in the wireless telecommunication system that uses smart antenna will be provided.

Because wireless communication system can not be in all be in if having time oepration at full load, always having some time slots has idle the time.Be that any capability of wireless communication system design all has certain redundancy, oepration at full load fully always has some time slots meetings idle, and the base station just can utilize these idle time slots to calculate ascending power and uplink beam figuration matrix; Under the electromagnetic environment of cleaning, the thermal noise that the signal that idle code channel is received is pure, at this moment the ascending power of the idle code channel of receiver equals the sensitivity of receiver; The uplink beam figuration matrix of idle code channel has characterized the characteristic of thermal noise at this moment, therefore because the noise of different time-gap is incoherent (coefficient correlation is minimum), the uplink beam figuration matrix of the idle code channel that obtains from thermal noise also is incoherent at different time-gap.

Under interference environment (being under the true environment for use), the ascending power of idle code channel is higher than the sensitivity of system, and interference signal is uncorrelated with communication signal, even therefore exist through still having interference signal after the relevant treatment on all code channels.Because the directivity of interference signal, so the uplink beam figuration matrix of interference signal is correlated with at different time slots.

Therefore can monitor electromagnetic environment and the interference source orientation of SCDMA according to the coefficient correlation between the uplink beam figuration matrix of the ascending power of idle code channel and idle code channel different time-gap.The inventive method may further comprise the steps:

A. select any idle code channel (time slot) on the base station, baseband signal processing unit calculates the uplink beam figuration matrix S I (t) and the power I of this free time code channel; Wherein, this code channel received signal is carried out utilizing the smart antenna algorithm to estimate the complex gain of each radio-frequency channel after the relevant treatment, can obtain matrix S I (t); And this code channel received signal is carried out the symbol (Symbol) that relevant treatment obtains this code channel, calculate the energy of each symbol, and these energy summations are obtained power I;

B. according to the calculating of above step a, judge that further the electromagnetic environment of this wireless system has noiseless;

C. judging that the direction of SI (t) has just characterized the direction of interference source, thereby interference signal is located under the noisy situation.

Preferably, judge that this electromagnetic environment has glitch-free step can be the mean value that calculates N idle code channel (time slot) power I $\stackrel{\‾}{I}=\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}{I}_n/N,$ Rated output thresholding I _c, with I and I _cCompare, if I＞I _c, thinking has interference, otherwise thinks and do not disturb.

Preferably, judge that this electromagnetic environment has glitch-free step also can be the mean value that calculates N idle code channel (time slot) coefficient correlation C $\stackrel{\‾}{C}=\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}{C}_n/N,$ With C and coefficient correlation thresholding C _TCompare, if C＞C _T, thinking has interference, otherwise thinks and do not disturb.

Preferably, judge that this electromagnetic environment has glitch-free step also can be the mean value that calculates N idle code channel (time slot) coefficient correlation C $\stackrel{\‾}{C}=\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}{C}_n/N,$ And the mean value of N idle code channel (time slot) power I $\stackrel{\‾}{I}=\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}{I}_n/N,$ Rated output thresholding I _c, if I＞I _cAnd C＞C _T, thinking has interference, otherwise thinks and do not disturb.

Preferably, power threshold I _cBe T/c, wherein T is the sensitivity of wireless system, and it is a design objective of wireless system; C is a regulatory factor, and its value is empirical value.

Preferably, the coefficient correlation C computational methods of idle code channel are: $C=\frac{|\mathrm{SI}\left(t_1\right)\·\mathrm{SI}\left(t_2\right)|}{\left|\mathrm{SI}\left(t_1\right)\right|\·\left|\mathrm{SI}\left(t_2\right)\right|},$ SI (t wherein ₁) and SI (t ₂) be any two moment t ₁And t ₂Idle code channel (time slot) uplink beam figuration matrix, these any two idle time slots can be two idle time slots of continuous two idle time slots or interval certain hour.

Preferably, coefficient correlation thresholding C _TBe the empirical value that obtains by analysis of data collected.

The inventive method has made full use of the characteristics of antenna system, monitor the electromagnetic environment of SCDMA according to the coefficient correlation between the uplink beam figuration matrix of the ascending power of idle code channel and idle code channel different time-gap, can monitor the electromagnetic environment of the wireless telecommunication system that uses smart antenna easily and accurately, and interference source is positioned.

Description of drawings

Read in conjunction with the accompanying drawings, the detailed description of specific embodiments of the invention is more readily understood.In the accompanying drawing:

Fig. 1 is to use the operation principle schematic diagram of base station in the wireless telecommunication system of smart antenna;

Fig. 2 is the embodiment of the invention to the judgement of interference source and to the flow chart of interference source orientation method.

Embodiment

Fig. 1 shows the operation principle of base station in the wireless telecommunication system that uses smart antenna, compare with base station traditional, that do not have smart antenna, it has formed its radio frequency part by an antenna array and one group of transceiver on hardware, base band signal process partly is used for the calculating of smart antenna received signal.

The SCDMA system design is 32 code channels, and real work at most only may be used 31 code channels, and therefore idle code channel is always arranged; Idle code channel and other code channel are code channel arranged side by side, and function is identical.The method of SCDMA Interference Detection is with any idle code channel, and the signal that idle code channel is received carries out the ascending power and the uplink beam figuration matrix of despreading, computation-free code channel.As shown in Figure 2, the present invention can press step enforcement:

At first, select an idle code channel (time slot) of base station, the uplink beam figuration matrix S I (t) and the power I of baseband signal processing unit computation-free code channel; Wherein, SI (t) is Xj (n) by relevant treatment, utilizes the smart antenna algorithm then, estimates the matrix that the complex gain of each radio-frequency channel obtains; I through relevant treatment, obtains the symbol (Symbol) of this code channel by Xj (n), calculates the energy of each symbol, and these energy summations are obtained.

Secondly, calculate any two moment t ₁And t ₂Idle code channel (time slot) uplink beam figuration matrix S I (t ₁) and SI (t ₂) coefficient correlation $C=\frac{|\mathrm{SI}\left(t_1\right)\·\mathrm{SI}\left(t_2\right)|}{\left|\mathrm{SI}\left(t_1\right)\right|\·\left|\mathrm{SI}\left(t_2\right)\right|}.$

Next step calculates the mean value I of N idle code channel (time slot) power I and the mean value C of coefficient correlation C, $\stackrel{\‾}{I}=\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}{I}_n/N,\stackrel{\‾}{C}=\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}{C}_n/N.$

Next step compares I and C respectively with power threshold and coefficient correlation thresholding, noiseless can the judgement with one of following judgment condition or in conjunction with two conditions arranged:

(1) if I＞I _c, thinking has interference, otherwise thinks that the environment of wireless system does not disturb, wherein, and power threshold I _c=T/c, T are the sensitivity of wireless system, and c is a regulatory factor, and is relevant with number of users, and c=1 when not having the user in theory is during N user $c=1/\sqrt{N},$ But in fact c should be an empirical value.

(2) if C＞C _T, then thinking has interference, otherwise thinks that the operational environment of wireless system does not disturb, at this moment the signal space characteristic vector SI (t of idle code channel ₁) and SI (t ₂) just characterized the direction of disturbing, utilize this space characteristics vector just can determine the direction of interference source, wherein C _TBe the coefficient correlation thresholding, also need to be provided with according to concrete the application.Different systems, C _TA great difference can be arranged, and this depends on the parameter characteristic of system; It is according to an empirical value on the basis of Systems Theory reckoning, should obtain by analysis of data collected.

At last, obtain testing result.As judgement interference is arranged, then the direction of Ci Shi SI (t) has just characterized the direction of interference source.

Claims (7)

1. method of monitoring the electromagnetic environment of the wireless telecommunication system that uses smart antenna is characterized in that this method may further comprise the steps:

A. baseband signal processing unit calculates the uplink beam figuration matrix S I (t) and the power I of this base station one idle code channel; Wherein, this code channel received signal is carried out utilizing the smart antenna algorithm to estimate the complex gain of each radio-frequency channel after the relevant treatment, can obtain matrix S I (t); And this code channel received signal is carried out the symbol (Symbol) that relevant treatment obtains this code channel, calculate the energy of each symbol, and these energy summations are obtained power I;

B. according to the calculating of above step a, judge that further the electromagnetic environment of this wireless system has noiseless;

C. judging that the direction of SI (t) has just characterized the direction of interference source, thereby interference signal is located under the noisy situation.

2. the method for claim 1 is characterized in that, judges that this electromagnetic environment has glitch-free step to be:

Calculate the mean value of N idle code channel (time slot) power I $\stackrel{\‾}{I}=\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}{I}_n/N,$ Rated output thresholding I _c, with I and I _cCompare, if I＞I _c, thinking has interference, otherwise thinks and do not disturb.

3. the method for claim 1 is characterized in that, judges that this electromagnetic environment has glitch-free step to be:

Calculate the mean value of N idle code channel (time slot) coefficient correlation C $\stackrel{\‾}{C}=\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}{C}_n/N,$ With C and C _TCompare, if C＞C _T, thinking has interference, otherwise thinks and do not disturb.

4. the method for claim 1 is characterized in that, judges that this electromagnetic environment has glitch-free step to be:

Calculate the mean value of N idle code channel (time slot) coefficient correlation C $\stackrel{\‾}{C}=\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}{C}_n/N,$ And the mean value of N idle code channel (time slot) power I $\stackrel{\‾}{I}=\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}{I}_n/N,$ Rated output thresholding I _c, if I＞I _cAnd C＞C _T, thinking has interference, otherwise thinks and do not disturb.

5. as the described method in one of claim 2 or 4, it is characterized in that power threshold I _cBe T/c, wherein T is the sensitivity of wireless system, and c is a regulatory factor, and its value is empirical value.

6. as utilizing the described method in one of claim 3 or 4, it is characterized in that the coefficient correlation computational methods of selected idle code channel are: $C=\frac{|\mathrm{SI}\left(t_1\right)\·\mathrm{SI}\left(t_2\right)|}{\left|\mathrm{SI}\left(t_1\right)\right|\·\left|\mathrm{SI}\left(t_2\right)\right|},$ SI (t wherein ₁) and SI (t ₂) be any two moment t ₁And t ₂Selected idle code channel (time slot) uplink beam figuration matrix, these any two idle time slots can be two idle time slots of continuous two idle time slots or interval certain hour.

7. as utilizing the described method in one of claim 3 or 4, it is characterized in that the empirical value of coefficient correlation thresholding CT for obtaining by analysis of data collected.