CN101485111B - Satellite interference cancelling - Google Patents
Satellite interference cancelling Download PDFInfo
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- CN101485111B CN101485111B CN200780024703.6A CN200780024703A CN101485111B CN 101485111 B CN101485111 B CN 101485111B CN 200780024703 A CN200780024703 A CN 200780024703A CN 101485111 B CN101485111 B CN 101485111B
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Abstract
A satellite interference canceling system cancels the interference between two or more signals received by a satellite receiver. The signals can be two signals experiencing cross polarization interference or signals that experience interference from other satellite signals. Gain and phase are applied to the received signals and then combined with the other signals to result in cancellation by subtraction. The gain and phase values needed to cancel the interference are derived from measurements of carrier-to-noise ratio (C/N) as an indication of the interference level. The C/N can be measured in the set-top box indoor unit. Coherency restoration is performed in receivers that downconvert the signals before performing interference cancellation.
Description
Related application
That the application requires to include in by reference is that submit to this 30 days June in 2006, U.S. Provisional Application that be entitled as " Satellitecross polarization canceling (satellite cross polarization counteracting) " N.60/817,951 priority.
That the application requires to include in by reference is that submit to this 24 days Augusts in 2006, U.S. Provisional Application that be entitled as " Satelliteinterference canceling (satellite interference counteracting) " N.60/839,860 priority.
N.60/870 the application requires to include in by reference the U.S. Provisional Application submitted to this 18 days December in 2006, be entitled as " Satelliteinterference canceling and frequency translation (satellite interference is offset and frequency translation) ", 609 priority.
Background
Invention
The interference that other satellite-signal that the present invention relates generally to reduce to be received and processed by this system in satellite receiving system causes.
Prior art
Satellite broadcast signal designs by combined antenna and signal timing forms orthogonal space in order to reuse the frequency spectrum of signal.Two signals sharing overlapping frequency are polarized to allow at the receiver place separately when transmitting.Due to atmospheric conditions, antenna design constraints, signal panels and antenna alignment and signal isolation (in low noise block frequency converter (LNB) or switch), therefore take two kinds of Polarization Mechanism of same frequency signal by the other side interfering with each other.Public keys about this is cross polarization interference.
Include in by reference and authorize U.S. Patent No. 5 Blodgett, that be entitled as " Apparatus andmethod for electronic polarization correction (apparatus and method of proofreading and correct for electronic polarization) " this 2 days June in 1998,760,740 have described a kind of circuit arrangement, sort circuit is arranged under optimized relative amplitude and phase place antenna output signal is applied to combiner, basically to offset the cross polarization energy of the second electromagnetic signal received.
Include in by reference and authorize U.S. Patent No. 4 people such as Beguin, that be entitled as " Radarsystem with circular polarized transmission and adaptive rain depolarizationcompensation (radar system with Circular Polarisation transmission and the compensation of self adaptation rain depolarization) " this 8 days Augusts in 1978,106,015 described a kind of for detection of two phase deviations of receiving interchannel and automatically regulate the amplitude one of at least of two channels and phase place so that compensation rain causes the device of (rain) depolarisation effect.
From the viewpoint of reception and transmitting antenna, signal is polarized into only has vertically or only has horizontal component.The mode spontaneous emission machine that the ripple of each signal leaves the accurate identical physical orientation of transmitter with it propagates into receiver.In the simple daylight that uses spreadlight lens filters, similar situation is arranged, wherein horizon light is by directed spreadlight lens and visible, thus the horizontal component of light as seen and vertical component be removed.Individually, when another spreadlight lens is rotated 90 ° with respect to first front lens, only vertical light is transmitted.The second receiver lens directed as filtering lens will be refused reverse polarization and only polarize by expectation.In the satellite system of usage level/perpendicular polarization, the selectivity of antenna is similar to the optics inference.
Antenna pointing error, or in other words, the reception antenna angle mismatching makes isolation reduce 20*LOG (angle of mismatch) doubly.
Outside the polarization of the gentle vertical type that dewaters, also have dextrorotation and left-handed Circular Polarisation, wherein given signal takies vertical and horizontal polarization simultaneously, and its difference is the sequence between the vertical and horizontal polarization.Vertical signal on time and physical space, fall behind or top standard's signal to determine the direction of polarization.
After the depolarising of antenna place, signal is converted into electrical representation---and be denoted as in this article signal A and B, wherein A is that wherein major part is at first by the signal of telecommunication of right-hand polarization, and B is from the left-handed polarization signal.Perhaps equivalently, in separate payment, signal A is most of signal of telecommunication from horizontal polarization, and B is from perpendicular polarization.
In heavy showers (rain causes decline), in the period, decay increases, and the isolation between dextrorotation and left-handed polarization signal is further demoted.
Need to remove two cross pollutions between polarizations to proofread and correct the isolation degradation in transmission and reception period generation.
Cross pollution between polarizations, signaling channel can experience the interference from other source.Outdoor unit can be in conjunction with two or more LNB to receive the signal from a plurality of satellites that are positioned at different orbit gaps.The directivity of reception antenna has been assembled the main signal from satellite to a LNB.Radio frequency (RF) or intermediate frequency (IF) signal from the channel that takies overlapping frequency of other satellite can cause disturbing.This can be called as the intersection satellite interference or sew.Interference in receiving element may be from other source.Interference signal may be from wishing signal, aiming at or have the transponder channel of frequency offset.
LNB output drives indoor unit, and the latter can be Set Top Box, media center or miscellaneous equipment tuning, demodulation code video frequency program.
To the further processing of desired signal, can be subject to from the same satellite cross polarization interference or from the adverse effect of the interference of the signal of other satellite.The economy of the interference RF that needs a kind of counteracting to receive to exist in satellite-signal or the impact of IF signal and efficient device.
Summary of the invention
The present invention is for offsetting the method and apparatus of the interference between the two or more signals that received by satellite receiver.Processed can be that two signals, experience of experience cross polarization interference are from the signal of the interference of other satellite-signal or experience the signal of the combination of two kinds of interference sources with the signal that carries out Interference Cancellation.All signals of experience phase mutual interference are received simultaneously, and each receives that signal is also potential interference source for other signal.To receiving signal application gain and phase place, and will be through gain and phase-adjusted signal and other signal combination with by from being disturbed signal, deducting interference signal and realize counteracting.Determine balance out disturb required gain and phase value can pass through the whole bag of tricks---for example using the indication of carrier-to-noise ratio (C/N) as interference level---realizes.Have distinct methods, these methods can be used to find out the optimum gain that will be applied to interference signal and phase place to maximize the counteracting of unexpected signal, minimise interference thus.
The actual power level of the interference existed in the calculation expectation signal in an embodiment of the present invention.Gain in the adjusting bucking circuit and phase place are to balance out interference.The method is measured C/N for the phase place of predetermined number under two different capacity level.Phase calibration and the amplitude of data inserting to determine that the highest C/N of realization is required.The highest C/N is corresponding to the least interference amount.
The second embodiment of the present invention is applied to interference signal by predetermined gain, and stepping is coupled to interference signal to be disturbed signal simultaneously by one group of selected phase value.Cause the phase value of maximum C/N to be used to arrange the phase place of bucking circuit subsequently.The gain that is applied to interference signal is conditioned subsequently on the scope of more than one value, to change the amplitude of offseting signal.Cause the amplitude of the highest C/N to be used to arrange the gain of bucking circuit subsequently.
Carrier-to-noise ratio is measured by the receiver demodulator.The present invention is economical and efficient, because it utilizes the existing demodulator in Set Top Box or miscellaneous equipment to determine C/N.The C/N data of control unit based on from Set Top Box are identified for correcting gain and the phase place setting that maximum interference is offset.Control unit can reside in outdoor unit or Set Top Box.
When the interference signal of receiving is coupled to while being disturbed signal path, the signal be coupled must be relevant so that the generation of offsetting with original interference signal.If two are received that signal carried out down-conversion by the frequency mixer driven with asynchronous local oscillator before bucking circuit, the signal be coupled and primary signal are by irrelevant.Coherence's restore circuit is proofreaied and correct coherency issues.In a kind of way, coherence's restore circuit uses the identical LO used with being disturbed signal path to carry out the phase mixing interference signal.In possible alternative, coherence's restore circuit will be coupled the frequency error of the frequency shift (FS) of signal by the introducing of frequency mixer process, to recover to be coupled the coherence between signal and original interference signal.
Brief Description Of Drawings
Fig. 1 shows the satellite receiving system that has the intersection pole cancellation according to of the present invention.
Thereby Fig. 2 shows and coupling of the present invention, between two paths, use a shared oscillator to retain the coherence's who is converted signal typical LNB circuit.
Fig. 3 shows when the signal for offsetting and the signal coherence that will be cancelled and the Interference Cancellation circuit of coupling of the present invention.
Fig. 4 shows the present invention who uses such as the passive component of variable attenuator and directional coupler.
Fig. 5 shows the phase place of the interference for measuring cross polarization or other type and the step of amplitude level.
Fig. 6 shows and uses direct method phase place and amplitude to be set to offset the step of interference signal.
Fig. 7 shows the block diagram of time delay counterbalanced procedure.
Fig. 8 shows and is using before for example circuit carries out any frequency translation as shown in Figure 9, under receive frequency, uses to have to intersect the satellite receiving system of switching circuit of pole cancellation.
Fig. 9 shows the block diagram according to the switching circuit of utilization of the present invention " by frequency (on-frequency) " intersection pole cancellation.
Figure 10 shows and utilizes Interference Cancellation to offset the block diagram of the switching circuit of intersection satellite interference.
Figure 11 shows the block diagram of an embodiment of the Interference Cancellation circuit 1002 of Figure 10.
Figure 12 shows when signal is irrelevant and the example of coherence's Interference Cancellation circuit need to be resumed or create the time.
Figure 13 shows the coherence of recovery or establishment signal to carry out the another kind of technology of best Interference Cancellation.
Figure 14 shows for the intersection satellite interference of two satellites and offsets and cross polarization is offset both and can be realized with the present invention.
Embodiment
Bucking circuit of the present invention is subject to cross polarization or intersects two signals of satellite interference impact.A and B signal path are provided.Every signal path deducts from another signal path, signal that be driven through adjustable phase shifter and adjustable gain circuit.Phase place and gain are set as the signal of offsetting from another path.Signal plus method or signal combination are equivalent to carries out suitable phasing by the signal to being subtracted and realizes signal subtraction.
In order to make counteracting method can carry out work, must be concerned with each other for the volume signal of offsetting and the signal that will be cancelled, and be in same frequency.This will guarantee the anti-phase time that is independent of, and counteracting is kept continuously.The coherence can lose because of frequency conversion process.If offset (being called " by frequency " herein processes) before any frequency translation, interference and offseting signal are concerned with, and can carry out counteracting method thus.No matter disturb from cross polarization, the satellite or, from any other source, this all sets up of intersecting.Even for frequency translation, if the interference signal of receiving when using relevant local oscillator and be disturbed signal on the identical frequency translation of generation, the coherence is kept.This is in the situation that share identical oscillator or use phase place to lock onto the situation of different oscillators of the same frequency in same reference source.If use the coherent oscillator of incoherent generation device or different frequency,, before counteracting method can be employed, the coherence must be resumed.The method of recovering the coherence before counteracting is being discussed after a while.
Realize to offset required appropriate phase place and gain and be from remote equipment---such as Set Top Box (STB) or integrated receiver decoder (IRD)---the carrier noise (C/N) that carries out measure and derive.Be arranged in the existing demodulator of remote equipment by use, given counteracting method is economical and efficient.Counteracting can be by monitoring that C/N adjusting gain and phase place are to keep maximum C/N to carry out self adaptation.Alternatively, the erector instrument that C/N also measures the ability of other index that can be by having sensing C/N or measures signal quality is made when mounted.
The level of cross polarization or other interference is to use interpolation method to determine by measuring C/N under the out of phase setting at the Interference Cancellation circuit and different capacity level.The another kind of way of determining required correction parameter is the iteration way of using such as gradient method.Must be calculated thus and be applied to offset the programmable phase in single channel and gain to remove cross polarization or interference by correction parameter.In addition, any intrinsic amplitude inaccuracy in phase shifter is eliminated.The Interference Cancellation circuit can be positioned at outdoor unit (ODU), and the latter communicates by letter with the STB that is measured and also receive calibrated signal.
In another embodiment of the present invention, used diverse ways (being referred to herein as direct method) determining must correction parameter the time.The method has avoided the plural number of previous described interpolation method to calculate.Backup path B is injected under the predetermined power level lower than the primary signal level, and measures C/N to determine the phase place that obtains best C/N in each phase place step.The phase place of backup path signal is set as the optimum phase setting, and power is adjusted to the power level of reaching best C/N back and forth subsequently.Phase place and level setting as a result provides offsets the maximum of non-hope interference signal.
Injection can be extended to some potential possible interference signal paths from the particular phases of the interference signal of another signal path and the way of level.But a kind of control phase and each interference path of gain path tap are also injected the controlled signal level to calibrated path.C/N or other quality index are made to measurement to determine respectively optimum phase and the gain of each signal path.The interference that place, in path until the arbitrfary point of measurement point causes can be corrected.
In the situation by realize on the different frequency in working range offsetting simultaneously, for example, for optimization takies the reception of the various transponders of relatively wide bandwidth or whole frequency band, also need to postpone (electricity or the time delay of the signal relative with phase shift usually are called " phase delay ") to regulate except phase adjusted.Typically, only use phase adjusted, only can obtain on single frequency or in narrow-band for the optimum angle of offsetting.Outside narrow band frequency, for the phase place of the phase place of the signal of offsetting and the signal that will be cancelled, will be different each other.As everyone knows, phase shift and frequency are proportional, and delay is proportionality constant.Therefore, when receiving broadband, the signal larger at frequency difference will have different phase shifts before arriving Interference Cancellation point, unless the time delay of two paths is complementary on these frequencies.If be to determine on one of frequency of frequency band for the phase value of offsetting, for other frequency in this frequency band, can not the phase calibration value, unless time delay also is complementary on all frequencies.In addition, postponing this may not be constant on frequency band, that is, it may present certain changeability across frequency band.This is called as " group delay " or " group delay overview " typically, and relative bandwidth or fractional bandwidth (being defined as the bandwidth of dividing by the centre frequency of frequency band) are narrower, and group delay overview is lower, therefore easier matching delay.At higher frequency place, fractional bandwidth is often narrower.For example, on the Ku of 12GHz frequency band, the 500MHz range of signal is about 4% mark BW only, and, under the L of 2GHz frequency band, identical 500MHz scope will mean 25% mark BW.Typically, on 4% BW than easier matching delay on the BW 25%.
In the present invention, in order to realize the counteracting on whole bandwidth, programmable delay element is added and carries out and postpones to regulate.For control lag, measure the C/N of two or more channels, be preferably included in two channels on arbitrary edge of frequency band.Each control lag and phase shift once, until reach best C/N on measured channel.By also utilizing time delay to regulate except amplitude and phase adjusted, can on whole frequency band, determine the optimization of offsetting simultaneously, but not optimization of every channel (that is, transponder channel).Depend on group delay overview and the degree that postpones to reach coupling, the degree of depth of Interference Cancellation can change on frequency band.May not reach real optimization to all channels, but can, by whole frequency band is reduced to system complexity with a path, still cause significant improvement in performance.
Interference Cancellation circuit and technology also can be used to offset the interference from the signal that comes from another satellite---and be called " intersection satellite " and disturb.Signal A from the first satellite can comprise the interference signal B from the second satellite.Signal B in offseting signal A is by deduct the version through decay and phase shift of primary signal B from signal A.
Traditionally, outdoor unit has will provide the LNB of the first frequency down-conversion of signal.One embodiment of the present of invention are that down-conversion only is provided, and this down-conversion will occur after the Interference Cancellation circuit.This embodiment will guarantee that the coherence of signal (from a satellite) is kept and it causes the system of simplifying.Another embodiment of the present invention application of interference after frequency translation is offset---suppose that frequency translation is to carry out with coherent manner.If do not keep the coherence in downconversion process, at first another embodiment of the present invention is recovered the coherence and is carried out Interference Cancellation subsequently.
Fig. 1 shows the satellite receiving system with intersection limit Interference Cancellation.Outdoor unit comprises antenna 104, LNB 106, Interference Cancellation circuit 108, switch and conversion road 110 and control unit 112.In outdoor unit (ODU), antenna 104 receives two polarized signals 102 (L) and 103 (R) and presents to low noise block frequency converter 106 (LNB), and the latter amplifies the high frequency satellite-signal and it is downconverted to lower intermediate frequency (IF) signal.The IF signal generally 950 to 1450MHz or wider 950 in the 2150MHz scope, this still is considered to radio frequency (RF).Two polarized signals are all available in LNB output place.In this example, local oscillator (LO) is DRO type (media resonant oscillator), usually is used in LNB.Have the unexpected part of signal A in signal B, and the unexpected part of signal B also is present in signal A.Interference Cancellation circuit 108 is used to change phase place and the gain that is fed to two polarized signals in another signal.Switch 110 is present in ODU, so that any LNB output is coupled to any remote equipment---show in this example Set Top Box 114 (STB).STB 114 receives the IF signal and this signal demodulation decoding is entered to one or more TV channels.STB has for measuring the circuit of carrier-to-noise ratio (C/N).Control unit 112 can be arranged in ODU or remote equipment.The control unit that can comprise the CPU (CPU) of microprocessor is regulated bucking circuit 108 until amplitude and the phase place of intersection limit signal produce maximum C/N.
Alternatively, C/N measures and can carry out in any other place in ODU or system, or with erector, with the C/N measurement, carries out when mounted.C/N can directly measure by well-known technology.A kind of technology is to measure to receive the error radius of data sample with respect to the radius of this constellation around ideal constellation point.For example, in the QPSK signal, the ideal of four constellation point, nominal or be centered close on a circle and value that each receives that constellation point will have around ideal point distributes.Error radius can be defined by a for example ideal point standard deviation radius on every side.Alternatively, the mean square error of one group of constellation point can be calculated as the tolerance that means C/N.C/N can measure by bit or the packet error rate of measuring demodulated signal indirectly.
Fig. 2 shows and conventional LNB circuit 106 coupling of the present invention, use a LO who shares---a kind of exemplary configurations for saving cost and reducing complexity---between two paths.The auxiliary income of sharing LO is, it is relevant that down-conversion signal keeps, and simplifies thus Interference Cancellation after execution during mixing.If share LO, and substitute the non-Phase-Locked Oscillator of use, for optimum Interference Cancellation, need to make signal coherence, as discussed below.
Fig. 3 show with coupling of the present invention, for intersecting the Interference Cancellation circuit 108 of limit Interference Cancellation.Adjustable phase shifter 308 and adjustable gain 306 are applied to signal B, and consequential signal 314 (B ") is fed to the A path.Similarly, phase shift and gain are applied to signal A, and consequential signal 316 (A ") is fed to the B path.When the bucking circuit, phase place and gain are set as and are set to match amplitude and phase place by gain and are set to depart from and pollute 180 ° of signals and offset and receive the cross polarization signal existed in signal, and this causes deducting or offsetting.When being used in measurement pattern lower time, phase place and gain are set as the degree that test is polluted.In one embodiment of the invention, STB estimates that C/N compare and sends this value and processed for control unit, and this control unit driving typically is arranged in the Interference Cancellation circuit 108 of ODU.Communicating by letter between STB 114 and ODU can be used the well-known communication technology; Comprise that FSK controls or digital satellite equipment more senior and that generally use is controlled (DiSEqC).
Phase shift, gain and delay parameter are adjustable, and bucking circuit can be realized as and makes the parameter can be by well-known analog or digital circuit programming or change.
Fig. 4 shows and uses passive component to realize Interference Cancellation circuit 108 of the present invention.Depend on system requirements, the active block of Fig. 3 can substitute with passive device.The signal (314 and 316) that will be subtracted due to common expectation is less on amplitude, and is in than the level of receiving that interference signal is low, so gain circuitry can be used passive variable loss.Subtraction circuit 312 can be carried out with well-known transmission line directional coupler 402.Directional coupler can be realized or realize with converter in micro-band, strip line, coaxial cable or guide technology.
Fig. 5 shows the step of the interpolation method when the phase place of determining cross polarization or interference and amplitude level.If counteracting method comprises the delay adjusting except amplitude and phase adjusted, shown in accompanying drawing and method described below can be extended to and comprise the 3rd time parameter.
Predetermined gain/amplitude is applied to non-hope (interference) signal, for example, power level can be selected to than the little 10dB of expectation (being disturbed) signal.On this predetermined power level, the phase place stepping is by many discrete phase places (504).Apply the second power level (506), and the phase place stepping is by a scope (508).Being averaged loop (use M) is illustrated and makes and can under each phase place setting and power level, can carry out some tolerance.The order of phase place and power stepping can be reversed, wherein in each phase place, lower power be set and switch between two level.Can on the continuous circulation of a setting or stepping process, repeat to be averaged.Can be by new reading and accumulation storing value be sued for peace to obtain on average.
These steps are as follows:
1. under about 10dB decay, signal B is fed to signal A (power 1).
A. measure C/N record.
B. by phase rotating 1 phase step.
C. repeating step 1a is to 1b until used all phase step.
D. will decay and increase pdiff dB (producing power 2).Pdiff is the predetermined power level step sizes.
E. measure C/N record.
F. by phase rotating 1 phase step.
G. repeat 1e to 1f until used all phase step.
2. determine and the phase place stepping that maximum C/N differs from wherein between power 1 and power 2, occurs, and be recorded in the performance number under this phase place stepping, corresponding to p1max and the p2max of this phase place stepping.The value of p1max is to be adjusted to while realizing maximum constructive interference under the first power level the power in dBc when phase place; P2max is in the power of dBc under the second power level.
3. determine and the phase place stepping that minimum C/N differs from wherein between power 1 and power 2, occurs, and be recorded in the performance number under this phase place stepping, corresponding to p1min and the p2min of this phase place stepping.Value p1min is adjusted to while realizing maximum destructive interference under the first power level the power in dBc when phase place; Value p2min is in the power of dBc under the second power level.
4. determine the value of perrmax.In system, inherently, between the out of phase stepping, there is gain/attenuation poor.This species diversity need to be calculated from p1max, p1min, p2max and p2min value.Resultant error will be called as perrmax.Value perrmax is defined as in phase shifter the difference power owing to the manufacturability of this phase shifter.In broad-band phase shifter, amplitude is also non-constant on each phase place; In the present invention, this inaccurately compensated by value perrmax (in dB).
5. calculate the power of the signal B in signal A with the ptest function shown in following formula 1.
Because the relative power of the signal B in signal A is not accurately known, therefore will need to use p1max, p1min, p2max, p2min and β calculate.Value β is defined as the square root of the linear equivalence value (perrmaxLin) of perrmax.The result of calculating will be the power of non-desired signal (signal B) with respect to desired signal (signal A); This will be called as ptest.Formula 1 shows for calculating the formula of ptest (the linear equivalence value of ptest is denoted as ptestLin).
Formula 1:ptestLin=-((β α) (A-B)-α
2(C-A)-α (B-A)+D-B)/E
Wherein
The subduplicate inverse of the linear equivalence value of α=pdiff
A=p1minLin, the linear equivalence that wherein p1minLin is p1min.
B=p2minLin, the linear equivalence that wherein p2minLin is p2min.
C=p1maxLin, the linear equivalence that wherein p1maxLin is p1max.
D=p2maxLin, the linear equivalence that wherein p2maxLin is p2max.
E＝α-(-β+(β·α
2)+α
2-1)
Then, can calculate the power (or cross polarization or xpole) of the primary signal B of entering signal A.Use, from above β, ptest, p1max, p1min, p2max, p2min and pdiff number, can calculate intersection limit power.
6. calculate the power of the intersection limit power of the signal B in signal A with cross-pole point function pxpole.Formula 2 shows the equation about pxpoleLin, and wherein pxpoleLin is the linear equivalence of pxpole.
Formula 2:pxpoleLin=[(B-D-α
2(1-β
2) ptestLin)/(2 (β+1) α)]
2/ ptestLin
Finally, if necessary, can estimate with β, ptest, pxpole, p1max, p1min, p2max, p2min and pdiff the power of the noise of system under test (SUT).The equation that following formula 3 shows about pnoiseLin---linear equivalence of pnoise---, be summarized as pxpoleLin that use before obtained and the item of ptestLin value.
Formula 3:pnoiseLin=A-(ptestLin
1/2-pxpoleLin
1/2)
2
Another signal is repeated to this process, and wherein signal A is fed into B and is measured.Calculate phase place and gain to offset the cross polarization of two signals.Need to offset the cross polarization signal for two signals, because one or more Set Top Box may receive and process two polarization just at the same time.
In alternative embodiment, C/N is without likely measured under phase place in institute.For example, after being identified for the initial optimum angle of proofreading and correct, the narrower phase place stepping scope centered by initial optimum angle value can be used to follow the tracks of the change in the optimum angle value.Can install or channel-changing after or periodically or initiate new search on proper range with the scheduled time when system is not used.
Previous corrected value and value scope can be stored in order to for proofreading and correct searched phase range for optimum, upper and lower bound is set.Addedly, when the degradation of predetermined or self adaptation amount being detected, can trigger for intersecting the sequence of pole cancellation.
Offset sequence and can make the ffm signal degradation.Carrying out counterbalanced procedure during channel-changing will make the upset caused by counterbalanced procedure minimize.
Intersect pole cancellation maintain the cycle during, the measurement of optimum angle and amplitude is carried out intersecting limit power height after being enough to be recorded, and the change can be used as in C/N is measured.Once make this measurement feasible, previous counteracting intersection limit signal can be used to determine definite amplitude and the phase place of intersection limit degradation at present now.This can by rotatable phase and monitor mutually long with destructive interference, subsequently change a certain known quantity of power and again length mutually with disappear mutually phase measurement and re-execute with new intersect limit phase place and relative amplitude really the associated mathematics of phasing realize.At this, key is not make C/N compared with required when system operates any degradation be arranged.According to these measurements, can calculate and apply phase calibration, when being measured, the maximum counteracting for intersection limit signal can increase signal level subsequently.
The another kind of way that is called direct method herein is by disturbing phase place direct measurements C/N to be set, this phase place to be set as to optimal value and each obstacle gain is arranged to measurement C/N and be identified for offsetting phase calibration and the gain of interference signal so that optimum gain to be set subsequently to each.Preferably, use from non-hope interference path, be set as lower than wishing signal level---for example, with respect to wishing that signal is at-10dBc---the measured power level phase place is set.This phase place scans all potential possible phase place settings and determines and cause maximum the counteracting---for example, press the C/N measurement in Set Top Box---phase place.Phase place is fixed on this level subsequently, and gains by up-down adjustment to causing maximum level of offsetting.This direct measurement way has been avoided for deriving the complicated calculations of phase place and yield value.
Fig. 6 shows by direct method and phase place and amplitude is set to offset the step of interference signal.At the relative power level of expected interference roughly---for example, with respect to wishing that signal is at-10dBc---under by programmable phase and gain path by unexpected signal and desired signal addition (602).Phase place arranges stepping and record C/N (604) under each stepping.Phase place is set as the value (606) that wherein measures maximum C/N, and this is corresponding to least interference or maximum the counteracting.When Injection Signal and interference signal single spin-echo, offset.Regulate add the power level of signal to find maximum C/N (608).System work under the phase place that maximum C/N is provided and power level (610).
Interference may be from other satellite-signal of just being processed by ODU or IRD.There is the ODU that can be discrete some LNB that maybe can be integrated into a unit and form an interference source, because be downconverted to overlapping frequency from some broadband satellite signals of different satellites.Other point in conversion process or in signal path, can introduce and disturb at the horn antenna place.An interference may be preponderated, and therefore only needs single non-hope signal injection path.If more than one interference is all significant, can provides phase place and gain controlled injection path to inject and offset a plurality of signals.
Fig. 7 shows the block diagram that time delay is offset operation.Unexpected delay τ 1 and τ 2 introduce because of initial amplification and the filtering of input signal in LNB for example.Inhibit signal output 702 can be illustrated as
and output signal 704 can be illustrated as
, wherein
with
it is phase shift as a result.The output signal 706 of bucking circuit can be illustrated as
wherein τ 2 ' regulates delay afterwards, and
to regulate phase place afterwards.For optimum, offset---on all frequency-of-interest
equal
this is only when postponing and phase place is mated---be τ 2=τ 1 and
shi Fasheng.The C/N of the channel of the edge of frequency band---preferably---measures to carry out counteracting method if will proofread and correct wider frequency band for disturbing, to use at least two channels.Each adjusting time lag of first order and phase shift are until measure on channel and realize best C/N at each.
Fig. 8 is the block diagram that uses the dual-satellite system of the intersection limit bucking circuit with HF switch and change-over circuit 800.In this case, with low noise amplifier (LNA), replace LNB, therefore before the intersection pole cancellation, do not carry out down-conversion.Intersect pole cancellation at original frequency---for example under the Ku-frequency band, occur.After the intersection pole cancellation, signal is switched also down-conversion subsequently.Switching is to carry out under the original frequency of signal, and is called as in this article ' by frequency ' switching.Down-conversion can make each polarization take different frequency bands and consequential signal can be combined into the stacked signal of single band.
Fig. 9 shows the bucking circuit with ' by frequency ' switching of the present invention and frequency inverted.In this embodiment, polarized signal is concerned with, and can use the bucking circuit shown in Fig. 3; Without the coherence, recover.In this embodiment of the present invention, switch matrix 902 receiving among signal from receiving radio frequency (RF) selected two or more signals.By signals selected down-conversion and frequency translation, each signal fades to the different channels frequency.Signal through conversion is combined to form the stacked signal of channel (CSS).The stacked signal of channel flows into a plurality of tuners in Set Top Box (STB).Alternatively, signal can be that frequency band is stacked, thereby realizes wherein can using the band converted system (BTS) of better simply filter.Can use single down-conversion step, thus utilize signal carry out optimum Interference Cancellation by coherence of frequency the time reduced complexity, cost and phase noise.
In the bandwidth work with wider and postpone to regulate in 310 system, in Fig. 9 and 10, bucking circuit 108 separately and 1002 is positioned at needs in switch matrix 902 after each switch but not before being positioned at switch matrix 902, as shown in FIG..This is necessary, so as for selected channel at every output line adjusted optimum angle.This method will be poor efficiency comparatively, because every output line of switch will require to have the independent bucking circuit of sophisticated signal route and switching.If use delay parameter during neutralisation process, bucking circuit is shared and simplifies.
Figure 10 shows the block diagram of dual-satellite system configuration, and wherein the input of LNA is dextrorotation and the left-handed polarization signal from two satellites.In an embodiment of the present invention, Interference Cancellation circuit 1002 is used to offset the intersection satellite interference.Amplifying signal is fed to intersection satellite interference bucking circuit (for example, the circuit of the present invention 1002 shown in Figure 11).The output of bucking circuit is filtered, and flows into circuit 1000.Circuit 1000 comprises matrix switch piece 902, downconvert block 1004 and essential control circuit.The output of circuit 1000 can be combined to form channel or the stacked signal of frequency band that wherein can use single cable.This unit cable output can be connected to subsequently one or more Set Top Box.
Figure 11 shows the block diagram of the Interference Cancellation circuit 1002 of Figure 10.The coupling to another from a satellite receiver path is provided.
Figure 12 and 13 shows the technology of recovering or formed the coherence between two signals before Interference Cancellation.If by the signal down-conversion, and the separate oscillator do not locked by phase place carries out this downconversion process before the Interference Cancellation circuit, through the signal of down-conversion by irrelevant.By using illustrative method in Figure 12 or 13, can make signal coherence, and optimum Interference Cancellation can occur.In the identical adjustable gain of Fig. 3 and phase circuit 304 and Fig. 5 and Fig. 6, illustrated same procedure can be used to measure and offset the interference in the examples of circuits of Figure 12 and 13.
Exemplified with effective counteracting of the signal f2 (and the signal f1 that inputs 2 places) at input 1 place, required coherence recovers Figure 12.Input in the signal f1 at 1 place to exist and disturb f2.Local oscillator LO1 drives two frequency mixers 1202 and 1204.The output of frequency mixer 1202 will comprise the interference signal that frequency moves to LO1-f2 and move to the main signal of LO1-f1 together with frequency.In order optimally to offset this signal, need to make the signal f2 and the signal LO1-f2 that input 2 places be concerned with.This can realize by frequency mixer 1204.Input to frequency mixer 1204 is signal f2.Frequency mixer 1204 is shared same LO (LO1) with frequency mixer 1202.Therefore, the output packet of frequency mixer 1204 is containing signal LO1-f2.Phase shift and gain (circuit 304) are applied to the output of frequency mixer 1204 and deduct circuit 304 and the output of frequency mixer 1202.The definite of optimum gain and phase place setting determines according to illustrated same procedure in Fig. 5 and Fig. 6.Inputting the interference of the f1 existed in the signal f2 at 2 places will offset with frequency mixer 1206 and 1208 similarly.
Figure 13 shows the another kind of technology of recovering for the coherence.This technology forms LO signal LO1-LO2 to drive two single-side belts (SSB) frequency mixer (1308 and 1310) in each input by the difference in LO.Use the down-conversion mixer device 1302 of LO1 and use the down-conversion mixer 1304 of LO2 will input respectively 1 and input the signal down-conversion at 2 places.LO1 and LO2 are coupled to differential mixer 1306 to form LO signal LO1-LO2.This LO signal driver coherence recovers frequency mixer 1308 and 1310.
Figure 14 shows a simplified block diagram, and it is in the situation that is illustrated in dual-satellite system, perturbation technique of the present invention can be used to offset individual satellite signal cross polarization interference and can be used to offset the intersection satellite interference of a plurality of satellites.An embodiment who offsets matrix 1400 can be the combination of intersection limit Interference Cancellation circuit 108 and intersection satellite interference bucking circuit 1002.
Claims (27)
1. a counteracting is applied to the method for the interference on the first reception signal by the second reception signal, and described first and second receives signal and received by satellite receiver, and described method comprises:
To described first signal application adjustable gain with can regulate phase shift to produce the first signal through regulating;
The described first signal through regulating is combined to described secondary signal to produce calibrated signal;
Under the first gain level in order by a plurality of phase places and under the second gain level in order by a plurality of phase places;
Measure the carrier-to-noise ratio of described correction signal under each phase place and gain level;
Calculate described phase place and the gain level of described interference from carrier-to-noise ratio measured under each phase place and gain level; And
The value of described adjustable gain and phase shift is set to offset described interference.
2. the method for claim 1, is characterized in that, described is to initiate when recording the carrier-to-noise ratio degradation of scheduled volume in order.
3. the method for claim 1, is characterized in that, described the first gain level be before calculated for offsetting the level of described interference.
4. the method for claim 1, is characterized in that, described interference is the interference owing to the cross polarization signal from a satellite.
5. the method for claim 1, is characterized in that, described interference is the interference come from from the signal of another satellite.
6. the method for claim 1, is characterized in that, the counteracting of described interference is receiving under frequency of described two signals, to carry out before any frequency translation.
7. the method for claim 1, is characterized in that, also is included in described first signal and is added to the regulated time delay that described secondary signal causes described first signal before.
8. the method for claim 1, is characterized in that, described adjustable gain realizes with variable attenuator, and described combination realizes with directional coupler.
9. the method for claim 1, it is characterized in that, also comprise: by described first signal with selected local oscillator (LO) frequency phase mixing in order to described first signal is carried out frequency translation and realizes described first signal through regulating and from the coherence between the described interference of the described first signal in described secondary signal.
10. a counteracting is applied to the method for the interference on the first reception signal by the second reception signal, and described first and second receive signal is received by satellite receiver, and described method comprises:
Have adjustable gain and phase shifter circuit, for the outdoor unit to another by a signal combination, under the first power level stepping by a plurality of phase places and under the second power level stepping by a plurality of phase places in, receive that with described two one of signal drives remote equipment;
In described remote equipment, measure the carrier-to-noise ratio from the described signal of described outdoor unit under each phase place and power level;
Calculate described phase place and the level of described interference from the described carrier-to-noise ratio recorded under each phase place and power level; And
Described adjustable gain and phase shifter are set to be disturbed to offset.
11. method as claimed in claim 10, is characterized in that, described remote equipment is Set Top Box.
12. method as claimed in claim 10, is characterized in that, described remote equipment is media center.
13. a counteracting is applied to the method for the interference on the first reception signal by the second reception signal, described first and second receive signal is received by satellite receiver, and described method comprises:
Have adjustable gain and phase shifter, for the version of regulating through phase shift and amplitude of described secondary signal being added to the outdoor unit of described first signal, the described amplitude of described secondary signal is set as to low than described first signal, thereby when stepping is by a plurality of phase places, by the described Set Top Box of the signal driver through addition;
In described Set Top Box, the carrier-to-noise ratio (C/N) in each phase measurement from the described signal of described outdoor unit;
Determine the described phase place setting that causes described best C/N;
Described phase place is set as to the described phase place that causes described best C/N;
Regulate the described amplitude of described secondary signal when measuring described C/N and determining the described gain setting that causes described best C/N; And
Described adjustable gain is set as cause described best C/N described gain to offset described interference.
14. one kind has the satellite receiver that is applied to the Interference Cancellation of the interference on the first reception signal by the second reception signal for offsetting, described first and second receive signal is received by satellite receiver, comprising:
Be coupled to the low noise block transducer (LNB) of described the first and second signals, wherein said LNB comprises for the shared local oscillator (LO) by described the first and second signal down-conversions;
Interference Cancellation circuit (108) comprising:
Be coupled to the first adjustable gain and the phase circuit (304) of described first signal; And
Be coupled to first subtraction circuit (312) of described adjustable gain and phase circuit (304), wherein will
Described through the gain and phase-adjusted first signal from described secondary signal, deduct;
The device of the level disturbed for the first signal of determining described secondary signal; And
Determine and will be applied to the first adjustable gain and phase circuit (304) with the phase place of the described first signal of offsetting described secondary signal and existing and the device of yield value for the level disturbed based on described first signal.
There is the satellite receiver of Interference Cancellation 15. as claimed in claim 14, it is characterized in that, also comprise:
Described Interference Cancellation circuit (108) also comprises:
Be coupled to the second adjustable gain and the phase circuit of described secondary signal; And
Be coupled to the second subtraction circuit of described the second adjustable gain and phase circuit, wherein deduct from described first signal through gain and phase-adjusted secondary signal described;
The device of the level disturbed for the secondary signal of determining described first signal; And
Determine and will be applied to described the second adjustable gain and phase circuit (304) with the phase place of the described secondary signal offsetting described first signal and exist and the device of yield value for the level disturbed based on described secondary signal.
16. satellite receiver as claimed in claim 14, is characterized in that, the device of the described level disturbed for definite first signal is included in the measurement that indoor unit is carried out.
17. satellite receiver as claimed in claim 14, is characterized in that, the described measurement that comprises the carrier-to-noise ratio (C/N) to described secondary signal for the device of determining the level that first signal disturbs.
18. satellite receiver as claimed in claim 15, is characterized in that, the described measurement that comprises the carrier-to-noise ratio (C/N) to described first signal for the device of determining the level that secondary signal is disturbed.
19. satellite receiver as claimed in claim 15, is characterized in that, the device of the described level disturbed for definite secondary signal is included in the measurement that indoor unit is carried out.
20. satellite receiver as claimed in claim 14, is characterized in that, described the first adjustable gain and phase circuit (304) also comprise that first can regulate time delay circuit (310).
21. one kind has the satellite receiver that is applied to the Interference Cancellation of the interference on the first reception signal by the second reception signal for offsetting, described first and second receive signal is received by satellite receiver, comprising:
The first local oscillator;
Be coupled to first down-conversion mixer (1202) of described the first oscillator;
The second local oscillator;
Be coupled to second down-conversion mixer (1206) of described the second oscillator;
The first-phase dryness that is coupled to described the first oscillator is recovered frequency mixer (1204);
The second-phase dryness that is coupled to described the second oscillator is recovered frequency mixer (1208);
The first low noise amplifier, wherein input is coupled to described first signal, and output is coupled to described the first down-conversion mixer (1202) and described second-phase dryness is recovered frequency mixer (1208);
The second low noise amplifier, wherein input is coupled to described secondary signal, and output is coupled to described the second down-conversion mixer (1206) and described first-phase dryness is recovered frequency mixer (1204);
The first adjustable gain and phase circuit (304);
Be coupled to the first subtraction circuit of described adjustable gain and phase circuit (304), wherein deduct from described first signal through gain and phase-adjusted secondary signal described;
The device of the level disturbed for the secondary signal of determining described first signal; And
Determine and will be applied to adjustable gain and phase circuit (304) with the phase place of the described secondary signal offsetting described first signal and exist and the device of yield value for the level disturbed based on described secondary signal.
22. satellite receiver as claimed in claim 21, is characterized in that, also comprises:
The second adjustable gain and phase circuit;
Be coupled to the second subtraction circuit of described adjustable gain and phase circuit, wherein deduct from described secondary signal through gain and phase-adjusted first signal described;
The device of the level disturbed for the first signal of determining described secondary signal; And
Determine and will be applied to adjustable gain and phase circuit with the phase place of the described first signal of offsetting described secondary signal and existing and the device of yield value for the level disturbed based on described first signal.
23. satellite receiver as claimed in claim 21, is characterized in that, described the first adjustable gain and phase circuit also comprise that first can regulate time delay circuit.
24. satellite receiver as claimed in claim 21, it is characterized in that, the device of the described level disturbed for definite first signal is included in the measurement of the demodulator of indoor unit to the carrier-to-noise ratio (C/N) of described secondary signal, and described measurement is communicated to described for determining the device of phase place and yield value.
25. one kind has the satellite receiver that is applied to the Interference Cancellation of the interference on the first reception signal by the second reception signal for offsetting, described first and second receive signal is received by satellite receiver, comprising:
The first local oscillator;
Be coupled to first down-conversion mixer (1302) of described the first oscillator;
The first low noise amplifier that there is the input that is coupled to described first signal and be coupled to the output of described the first down-conversion mixer (1302);
The second local oscillator;
Be coupled to second down-conversion mixer (1304) of described the second oscillator;
The second low noise amplifier that there is the input that is coupled to described secondary signal and be coupled to the output of described the second down-conversion mixer (1304);
Be coupled to the differential mixer (1306) of described the first oscillator and described the second oscillator;
The first-phase dryness that is coupled to the described output of the output of differential mixer (1306) and described the first down-conversion mixer (1302) is recovered frequency mixer (1308);
The second-phase dryness that is coupled to the described output of the output of differential mixer (1306) and described the second down-conversion mixer (1304) is recovered frequency mixer (1310);
Be coupled to described first-phase dryness and recover the first adjustable gain and the phase circuit (304) of the output of frequency mixer (1308);
Be coupled to described second-phase dryness and recover the second adjustable gain and the phase circuit of the output of frequency mixer (1310);
Be coupled to the first subtraction circuit of described the second adjustable gain and phase circuit, wherein will deduct from described first signal through gain and phase-adjusted secondary signal;
Be coupled to the second subtraction circuit of described the first adjustable gain and phase circuit, wherein will deduct from described secondary signal through gain and phase-adjusted first signal;
The device of the level disturbed for the secondary signal of determining described first signal;
Determine and will be applied to the first adjustable gain and phase circuit with the phase place of the described secondary signal offsetting described first signal and exist and the device of yield value for the level disturbed based on described secondary signal;
The device of the level disturbed for the first signal of determining described secondary signal; And
Determine and will be applied to the second adjustable gain and phase circuit with the phase place of the described first signal of offsetting described secondary signal and existing and the device of yield value for the level disturbed based on described first signal;
26. one kind has for offsetting before down-conversion by the second reception signal and is applied to the satellite receiver that interference on the first reception signal keeps coherence's Interference Cancellation thus, described first and second receive signals is received by satellite receiver, comprising:
Be coupled to first low noise amplifier (LNA) of described first signal;
Be coupled to second low noise amplifier (LNA) of described secondary signal;
Offset and frequency-conversion circuit (800), comprising:
The first Interference Cancellation circuit (108) comprising:
Be coupled to the first adjustable gain and the phase circuit (304) of described first signal; And
Be coupled to first subtraction circuit (312) of described the first adjustable gain and phase circuit (304), wherein will deduct from described secondary signal through gain and phase-adjusted first signal;
The device of the level disturbed for the first signal of determining described secondary signal;
Determine and will be applied to the first adjustable gain and phase circuit (304) with the phase place of the described first signal of offsetting described secondary signal and existing and the device of yield value for the described level disturbed based on described first signal;
Be coupled to the matrix switch (902) of the first output of described the first Interference Cancellation circuit (108); And
Be coupled to the down-converter circuit of described matrix switch (902), wherein that the output of the output of described low-converter and other low-converter is combined to produce the stacked signal of frequency band.
There is the satellite receiver of Interference Cancellation 27. as claimed in claim 26, it is characterized in that, also comprise:
The second Interference Cancellation circuit (108) also comprises:
Be coupled to the second adjustable gain and the phase circuit of described secondary signal; And
Be coupled to the second subtraction circuit of described the second adjustable gain and phase circuit, wherein deduct from described first signal through gain and phase-adjusted secondary signal described;
The device of the level disturbed for the first signal of determining described secondary signal; And
Determine and will be applied to the second adjustable gain and phase circuit with the phase place of the described secondary signal offsetting described first signal and exist and the device of yield value for the described level disturbed based on described secondary signal.
Applications Claiming Priority (7)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US81795106P | 2006-06-30 | 2006-06-30 | |
| US60/817,951 | 2006-06-30 | ||
| US83986006P | 2006-08-24 | 2006-08-24 | |
| US60/839,860 | 2006-08-24 | ||
| US87060906P | 2006-12-18 | 2006-12-18 | |
| US60/870,609 | 2006-12-18 | ||
| PCT/US2007/072592 WO2008066968A2 (en) | 2006-06-30 | 2007-06-29 | Satellite interference canceling |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101485111A CN101485111A (en) | 2009-07-15 |
| CN101485111B true CN101485111B (en) | 2013-12-25 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200780024703.6A Expired - Fee Related CN101485111B (en) | 2006-06-30 | 2007-06-29 | Satellite interference cancelling |
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| CN (1) | CN101485111B (en) |
| ES (1) | ES2353145T3 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008064371A2 (en) * | 2006-11-03 | 2008-05-29 | Rf Magic, Inc. | Satellite signal frequency translation and stacking |
| CN101800678B (en) * | 2010-03-12 | 2012-05-23 | 华为技术有限公司 | Microwave transmission method, device and system applying CCDP and XPIC |
| TWI478484B (en) * | 2011-09-19 | 2015-03-21 | Richwave Technology Corp | Multiple-input multiple-output low-noise block downconverter and low-noise module |
| EP2830241B1 (en) * | 2013-07-23 | 2015-07-08 | Advanced Digital Broadcast S.A. | A method and system for determining parameters of a satellite signal |
| EP3400458B1 (en) * | 2016-01-04 | 2021-10-13 | Symeo GmbH | Method and system for the reduction of disturbance through phase noise in a radar system |
| CN108183742B (en) * | 2017-12-21 | 2021-04-20 | 北京九天微星科技发展有限公司 | Satellite communication method and device |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0331411A2 (en) * | 1988-02-29 | 1989-09-06 | Nippon Telegraph And Telephone Corporation | Interference cancellation circuit |
| CN1606838A (en) * | 2001-10-11 | 2005-04-13 | D.S.P.C.技术有限公司 | Interference reduction using low complexity antenna array |
-
2007
- 2007-06-29 ES ES07871002T patent/ES2353145T3/en active Active
- 2007-06-29 CN CN200780024703.6A patent/CN101485111B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0331411A2 (en) * | 1988-02-29 | 1989-09-06 | Nippon Telegraph And Telephone Corporation | Interference cancellation circuit |
| CN1606838A (en) * | 2001-10-11 | 2005-04-13 | D.S.P.C.技术有限公司 | Interference reduction using low complexity antenna array |
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| ES2353145T3 (en) | 2011-02-25 |
| CN101485111A (en) | 2009-07-15 |
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