CN1242581C - Real-time monitoring system for electromagnetic environment of synchronous CDMA communications system - Google Patents

Abstract

The present invention relates to a real-time monitoring method for electromagnetic environment of synchronous CDMA communications system, which comprises the following steps that data is collected from an upgoing synchronous time slot; whether an upgoing synchronous signal exists in a data frame or not is tested and judged from the collected data frame; when no upgoing synchronous signal is tested in an upgoing synchronous frame, the data frame carries out autocorrelation calculation; whether interference exists or not is judged; the number of interference sources inside a frequency range used by a base station, the transmission direction of the interference sources and the steps of sending out interference warning and channel failure toward a network management center are calculated. The method of the present invention monitors electromagnetic environment of the frequency range used by the current base station when the upgoing synchronous time slot is free; when interference is found, a transmission source of the interference is found out; when the interference is not found, a radio frequency receiving channel can be further monitored; when the interference or the failure is found in a channel, the present invention can send out warning to the network management center.

Description

A kind of method of real-time of synchronous code division multiple access communication system electromagnetic environment

Technical field

The present invention relates to the monitoring technical field of code division multiple address communication system, particularly relate to the monitoring of the electromagnetic environment of code division multiple address communication system.

Background technology

In S-CDMA (SCDMA) design of communication system, in each up time frame, all reserve a uplink synchronous time slot, its effect has following 3 points: a) access at random of mobile/fixed terminal; B) set up initial uplink synchronous; And c) finishing initial wave beam measures.

Fig. 1 is the flow chart of the method for detecting uplink synchronizing signals of existing code division multiple address communication system.Fig. 1 provides the processing procedure of the existing data that the uplink synchronous time slot is gathered.At first, then the data of uplink synchronous time slot collection are made coherent detection, differentiate in the data whether uplink synchronizing signals is arranged from uplink synchronous time slot image data.Because this uplink synchronous time slot (synch_UL) is not all occupied at each up time frame, have only when certain move/just on this time slot, launch uplink synchronizing signals when fixed terminal need be conversed.The base station just can allow this terminal to login and distribute the transmission of its certain free time (traffic) channel after receiving this uplink synchronizing signals.If there is not uplink synchronizing signals in the data, then stop to detect.If detect uplink synchronizing signals, the logging request of base station processing terminal then.Whether existing method for detecting uplink synchronizing signals just detection exists uplink synchronizing signals and handles accordingly, but can not carry out real-time monitoring to electromagnetic environment, can not judge whether to exist interference, the number of disturbing and definite direction of disturbing.

Summary of the invention

The objective of the invention is to realize that the electromagnetic environment to code division multiple address communication system monitors in real time, when the uplink synchronous time slot is not taken by the uplink synchronizing signals of certain or a plurality of terminals, the data that utilization collects at this time slot are analyzed and signal processing, to reach the electromagnetic environment in the shared transmission band in base station is comprised that the end makes an uproar, inner or external interference signal and the adjacent base station interference of frequency are together monitored in real time, in case find to have interference signal to exist, can determine to exist the number of interference, the source (direction) of adopting directional technology to find interference signal.When judging that existence is disturbed, can in time send alarm.And when not detecting interference, can whether normal by the receive path work of algorithm monitors radio frequency.When determining channel failure, send alarm.

The present invention proposes a kind of method of real-time of synchronous code division multiple access communication system electromagnetic environment, may further comprise the steps: from uplink synchronous time slot image data; From the data of gathering, detect and judge whether this time slot exists uplink synchronizing signals; If detect in the uplink synchronous time slot and do not have uplink synchronizing signals, in the frequency range that calculation base station adopted at the signal of uplink synchronous time slot, and this signal made auto-correlation computation, storage after the auto-correlation function matrix that obtains and the auto-correlation function matrix of earlier stored add up, add up, obtain being used to monitor the auto-correlation function matrix of electromagnetic environment, utilize this auto-correlation function matrix to judge whether to exist and disturb; When judging that existence is disturbed, the number of the interference source in the frequency range that calculation base station uses; With the transmit direction that calculates interference source; Wherein, described judging whether exists the step of interference to comprise: if the root sum square of the mould of each element of this auto-correlation function matrix square is more than or equal to α σ ², then judging has interference signal to exist, and symbol is the thresholding regulating constant, σ ²It is the noise power of radio-frequency channel, every road.Method of the present invention also comprises to network management center sends the step of disturbing alarm and channel failure.

Method of the present invention has expanded the application of uplink synchronous time slot, make when the uplink synchronous time slot is idle, use the image data that has obtained to use the electromagnetic environment of frequency range to monitor to current base station, when finding interference is arranged, the interference source of being found is carried out directional process, find out its emission source.When not finding to disturb, we can monitor radio frequency reception channel synchronously, can navigate to concrete certain radio-frequency channel fault has taken place, for example cable interface, broken string, radio-frequency devices damage etc., and when finding that passage has interference or fault, can send alarm to network management center, so that in time handle, thereby can improve the communication quality of synchronous code division multiple access communication system.

Description of drawings

Fig. 1 is the flow chart of the method for detecting uplink synchronizing signals of prior art.

Fig. 2 is according to the flow chart of embodiments of the invention realization to the electromagnetic environment monitor of synchronous code division multiple access communication system.

Embodiment

Fig. 2 is according to the flow chart of embodiments of the invention realization to the electromagnetic environment monitor of synchronous code division multiple access communication system.Be described in detail by the flow process of Fig. 2 below with reference to Fig. 2 and determine whether passage exists interference, disturb number and to calculate the transmit direction of interference source.

Suppose antenna array adopt M (M=1,2 ...) individual antenna element, the uplink synchronizing signals of SCDMA system adopts N ₁Individual chip (chip) length adds protection time slot (Guard period) N ₂, define total data acquisition and be spaced apart N=(N ₁+ N ₂) individual chip and total sampled value be N _K=(N ₁+ N ₂) * K.Here K is the sampling number of each chip.The data that collect like this can be used matrix Z={z _{M, n}Represent:

$Z=\left[\begin{array}{ccccccc}{z}_{\mathrm{1,1}}& z_{\mathrm{1,2}}& \·& \·& \·& \·& z_{1,N_K}\\ \·& \·& \·& \·& \·& \·& z_{2,N_K}\\ \·& \·& \·& \·& \·& \·& \·\\ \·& \·& \·& \·& \·& \·& \·\\ \·& \·& \·& \·& \·& \·& \·\\ \·& \·& \·& \·& \·& \·& \·\\ z_{M,1}& z_{M,2}& \·& \·& \·& \·& z_{M,N_K}\end{array}\right]---\left(1\right)$

M=1 in the formula, 2 ..., M; N=1,2 ..., N _K

Realize by image data Z is carried out coherent detection the detection of uplink synchronizing signals the base station, the specific implementation algorithm for example can adopt twice fast fourier transform (FFT) or directly image data be carried out convolution with the uplink synchronizing signals of launching, and adjudicates then that the size of its peak value realizes.

When the testing result of uplink synchronizing signals is represented the uplink synchronizing signals of login is arranged, by the logging request of base station processing terminal.When the testing result of uplink synchronizing signals is represented not have to find in this frame the uplink synchronizing signals of login to be arranged, these frame data are made auto-correlation computation, obtain to such an extent that auto-correlation function adds up mutually with the auto-correlation function value of earlier stored and stores, wait for the processing of next step then, Cun Zhu data frame number is given by the base station and putting here.The auto-correlation function computing can be adopted the data of all M paths or the data of part passage.In addition the data accumulated frame number by the base station give install fixed.The base station can utilize counter or timer to count fixedly frame number or Fixed Time Interval are set.

For the data Z that collects (formula 1), can get its a part of data and do the auto-correlation function computing, this part data note is Z _d, the auto-correlation function matrix that so just obtains it is

r _ZZ＝E{Z _d·Z _d ^H} (2)

R wherein _ZzIt is the auto-correlation function matrix of every frame alignment time slot Frame.Here Z _d ^HBe Z _dConjugation change order.Auto-correlation function matrix after obtaining adding up after the auto-correlation function value addition of this result and earlier stored is:

R _ZZ ⁽ⁿ⁾＝R _ZZ ^(n-1)+r _ZZ (3)

R wherein _ZZ ⁽ⁿ⁾Be the auto-correlation function matrix after the n frame adds up, n does not contain the number that uplink synchronizing signals and its data are used to do the frame of auto-correlation computation.Suppose in the frequency range that adopts in this base station and have L interference source s ₁(t), s ₂(t) ..., s _L(t), they come from deflection { θ respectively ₁, θ ₂..., θ _L, (white noise) made an uproar for N (t) in the end of channel, and the signal at the uplink synchronous time slot can be expressed as like this:

$Z\left(t\right)=\underset{l=1}{\overset{L}{\mathrm{\Σ}}}\left({\mathrm{\θ}}_l\right){\·S}_l\left(t\right)+N\left(t\right)---\left(4\right)$

Here α (θ _l) be that antenna array is at deflection θ _lSpace characteristics vector (spatial signature).

Obtain being used to monitor the data Z (t) of electromagnetic environment by formula (4), can judge whether to exist according to this result and disturb.At first, multiple signals Z (t) is done auto-correlation processing, and obtain the auto-correlation function matrix r _ZzFor:

$\begin{array}{c}{r}_{\mathrm{zz}}\≈\underset{l=1}{\overset{L}{\mathrm{\Σ}}}A\left({\mathrm{\θ}}_l\right)\·E\{S_l\left(t\right)\·S_l^H\left(t\right)\}\·A^H\left({\mathrm{\θ}}_l\right)+E\{N\left(t\right)\·N^H\left(t\right)\}\\ =\underset{l=1}{\overset{L}{\mathrm{\Σ}}}{P}_l\·A\left({\mathrm{\θ}}_l\right)\·A^H\left({\mathrm{\θ}}_l\right)+{\mathrm{\σ}}^{2\·}I\end{array}---\left(5\right)$

Here P _lBe the signal power of the 1st interference source, σ ²Be the noise power of radio-frequency channel, every road, I representation unit matrix.When not having interference signal to exist, obtain

R _ZZ ⁽ⁿ⁾≈n·σ ²·I (6)

Here n is the data accumulated frame number.Whether we can exist interference with following condition judgement like this:

Here ‖ R _Zz ⁽ⁿ⁾‖ is matrix R _ZZ ⁽ⁿ⁾The root sum square of mould square of each element, α is the thresholding regulating constant, its value be greater than

Real number, M ₁It is the dimension of auto-correlation function matrix.When judgement did not have interference signal, the base station was no longer done further monitoring and is handled, and gets back in the common working procedure.

In actual applications, can there be multiple algorithm that the interference source number is detected.Be to adopt to calculate R according to one embodiment of present invention _Zz ⁽ⁿ⁾Eigenvalue method.Can calculate M by the algorithm of asking characteristic value ₁Individual eigenvalue ₁, λ ₂..., λ _M1Again from M ₁Find out minimum characteristic value in the individual characteristic value and be designated as λ _MinSuppose that we find out n ₁Individual characteristic value all satisfies the following formula relation

λ _n＞＞λ _Min，

Then at this moment think and in this frequency range, have n ₁Individual interference source exists.Here " being far longer than " for example is greater than 5-10 doubly.

If the situation of having only interference source to exist, then the characteristic vector corresponding to the characteristic value of maximum is exactly the spatial signature vectors of this interference source.

Suppose the interference source number n that in the interference source number detects, obtains ₁=0, at this moment can judge necessarily has the passage more than a road or a tunnel fault to occur in radio frequency reception channel.Check auto-correlation function matrix R then _Zz ⁽ⁿ⁾Cornerwise value r ₁₁, r ₂₂..., r _M1M1, from these diagonal line value, find out a minimum value, if n is arranged ₂Individual value is far longer than this minimum value, and just judging has n ₂Break down in the radio-frequency channel, road.

When ruling out the number in interference signal existence and known disturbances source, the available transmit direction of further determining interference source can utilize following several algorithm to determine the transmit direction of interference source according to the present invention.

A) multiple signal classification method (MUSIC) algorithm

Multiple signal classification method algorithm is the method for the direction (DOA) that arrives of a kind of calculating of classics, and it can calculate the direction of each interference source accurately.It is comparatively complicated that but its shortcoming is its computing.

B) Capon (card Peng) algorithm

Utilize the Capon algorithm at first to calculate p (θ):

$p\left(\mathrm{\θ}\right)=\frac{1}{|a^H\left(\mathrm{\θ}\right)\·{\left(R_{\mathrm{zz}}^{\left(n\right)}\right)}^{-1}\·a\left(\mathrm{\θ}\right)|},$

(R in the formula _Zz ⁽ⁿ⁾) ^-1Be R _ZZ ⁽ⁿ⁾Inverse matrix; A (θ) is the space characteristics vector (spatial signature) of antenna array at deflection θ, 0≤θ＜2 π.

By calculating the peak value of p (θ), for example go out all peak values with threshold judgement, can find out the direction of interference source.

After finding that interference signal is arranged, the base station can be from the alarm of trend network management center, so that interference signal is found out and eliminated to webmaster.As not eliminating interference, can try every possible means to avoid to disturb.

Claims (9)

1. the method for real-time of a synchronous code division multiple access communication system electromagnetic environment may further comprise the steps:

From uplink synchronous time slot image data;

From the data of gathering, detect and judge whether this time slot exists uplink synchronizing signals;

If detect in the uplink synchronous time slot and do not have uplink synchronizing signals, in the frequency range that calculation base station adopted at the signal of uplink synchronous time slot, and this signal made auto-correlation computation, storage after the auto-correlation function matrix that obtains and the auto-correlation function matrix of earlier stored add up, adding up like this obtains being used to monitor the auto-correlation function matrix of electromagnetic environment, utilizes this auto-correlation function matrix that obtains that adds up to judge whether to exist interference;

When judging that existence is disturbed, the number of the interference source in the frequency range that calculation base station uses; With

Calculate the transmit direction of interference source;

Wherein, described judging whether exists the step of interference to comprise: if the root sum square of the mould of each element of this auto-correlation function matrix square is more than or equal to α σ ², then judging has interference signal to exist, and symbol is the thresholding regulating constant, σ ²It is the noise power of radio-frequency channel, every road.

2. according to the process of claim 1 wherein that from the step of uplink synchronous time slot image data be from M antenna element image data, the data of described collection are following matrix Z:

$Z=\left[\begin{array}{cccc}{z}_{\mathrm{1,1}}& z_{\mathrm{1,2}}& \·\·\·\·& z_{1,N_K}\\ z_{\mathrm{2,1}}& z_{\mathrm{2,2}}& \·\·\·\·& z_{2,N_K}\\ \·& \·& \·& \·\\ \·& \·& \·& \·\\ \·& \·& \·& \·\\ \·& \·& \·& \·\\ z_{m,1}& z_{M,2}& \·\·\·\·& z_{M,N_K}\end{array}\right]$

M=1 in the formula, 2, N is the data acquisition interval, N _K=N * K, K are the sampling numbers of each chip.

3. according to the method for claim 1, wherein said to judge whether to exist the step of uplink synchronizing signals be to adopt twice fast fourier transform or directly image data is carried out convolution with the uplink synchronizing signals of launching, and adjudicates then that the size of its peak value realizes.

4. according to the method for claim 1, the step of the number of the interference source in the frequency range that wherein said calculation base station uses may further comprise the steps: the characteristic value of calculating the described auto-correlation function matrix that obtains of adding up, find out minimum characteristic value, if in these characteristic values n is arranged ₁When individual characteristic value was far longer than this minimum characteristic value, just thinking had n in this frequency range ₁Individual interference source.

5. according to the method for claim 1, also comprise to network management center and send the step of disturbing alarm.

6. be to utilize direction calculating that the algorithm computation of multiple signal classification method arrives according to the process of claim 1 wherein that described calculation base station uses the step of the transmit direction of the interference source in the frequency range.

7. according to the process of claim 1 wherein that described calculation base station uses the step of the transmit direction of the interference source in the frequency range to utilize the Capon algorithm computation, may further comprise the steps: calculate p (θ) according to following formula:

$p\left(\mathrm{\θ}\right)=\frac{1}{\left|a^H\left(\mathrm{\θ}\right)\·{\left(R_{\mathrm{zz}}^{\left(n\right)}\right)}^{-1}\·a\left(\mathrm{\θ}\right)\right|}$

R in the formula _ZZ ⁽ⁿ⁾Be the auto-correlation function matrix after the n frame adds up, n does not contain the number that uplink synchronizing signals and its data are used to do the frame of auto-correlation computation; (R _ZZ ⁽ⁿ⁾) ^-1Be R _ZZ ⁽ⁿ⁾Inverse matrix; A (θ) is the space characteristics vector of antenna array at deflection θ, 0≤θ＜2 π; With utilize threshold judgement to go out all peak values of p (θ), obtain the direction of interference source.

8. according to the method for claim 1 or 4, when the step of the number of the interference source in the frequency range that wherein said calculation base station uses is zero in the number of the interference source that calculates, judge that then radio frequency reception channel breaks down.

9. method according to Claim 8, also comprise cornerwise value of checking the described auto-correlation function matrix that obtains of adding up, find out the minimum value of these diagonal line value, judge the number that is far longer than this minimum value in these cornerwise values, then this number is exactly the port number that breaks down.

Images