Ib hnub zoo.
Kuv tau siv ob peb xyoos dhau los tshawb fawb thiab tsim ntau yam algorithms rau spatial teeb liab ua nyob rau hauv adaptive kav hlau txais xov arrays, thiab txuas ntxiv ua ib feem ntawm kuv txoj hauj lwm tam sim no. Ntawm no kuv xav qhia cov kev paub thiab kev dag uas kuv nrhiav tau rau kuv tus kheej. Kuv vam tias qhov no yuav muaj txiaj ntsig zoo rau cov neeg pib kawm txog thaj chaw no ntawm kev ua cov teeb liab lossis cov neeg uas tsuas nyiam.
Dab tsi yog qhov adaptive kav hlau txais xov array?
- qhov no yog ib txheej ntawm cov kav hlau txais xov uas muab tso rau hauv qhov chaw hauv qee txoj kev. Ib qho yooj yim qauv ntawm adaptive kav hlau txais xov array, uas peb yuav xav txog, tuaj yeem sawv cev rau hauv daim ntawv hauv qab no:
Adaptive antenna arrays feem ntau hu ua "smart" antennas (). Dab tsi ua rau tus kav hlau txais xov array "ntse" yog qhov chaw ua haujlwm teeb liab thiab cov algorithms siv hauv nws. Cov algorithms no tsom xam cov teeb liab tau txais thiab tsim ib txheej ntawm qhov hnyav coefficients $inline$w_1…w_N$inline$, uas txiav txim siab qhov amplitude thiab thawj theem ntawm lub teeb liab rau txhua lub caij. Qhov muab amplitude-phase faib txiav txim siab lub lattice tag nrho. Lub peev xwm los tsim cov qauv hluav taws xob ntawm cov qauv uas yuav tsum tau ua thiab hloov nws thaum lub sijhawm ua cov teeb liab yog ib qho ntawm cov yam ntxwv tseem ceeb ntawm kev hloov kho kav hlau txais xov arrays, uas tso cai rau kev daws teeb meem ntau yam teeb meem. . Tab sis thawj yam ua ntej.
Cov qauv hluav taws xob tsim li cas?
characterizes lub teeb liab hwj chim emitted nyob rau hauv ib tug tej yam kev taw qhia. Rau kev yooj yim, peb xav tias cov lattice ntsiab yog isotropic, i.e. rau txhua tus ntawm lawv, lub zog ntawm lub teeb liab emitted tsis nyob ntawm qhov kev taw qhia. Lub amplification los yog attenuation ntawm lub hwj chim emitted los ntawm lub grating nyob rau hauv ib tug tej yam kev taw qhia yog tau vim Electromagnetic nthwv dej emitted los ntawm ntau yam ntawm lub kav hlau txais xov array. Ib qho kev cuam tshuam ruaj khov rau cov nthwv dej electromagnetic tsuas yog ua tau yog tias lawv , i.e. theem sib txawv ntawm cov teeb liab yuav tsum tsis txhob hloov lub sijhawm. Qhov zoo tshaj plaws, txhua lub caij ntawm tus kav hlau txais xov array yuav tsum radiate ntawm tib tus neeg nqa khoom zaus $inline$f_{0}$inline$. Txawm li cas los xij, nyob rau hauv kev xyaum ib tug yuav tsum ua hauj lwm nrog nqaim band signals muaj ib tug spectrum ntawm finite dav $inline$Delta f << f_{0}$ inline$.
Cia tag nrho AR ntsiab emit tib lub teeb liab nrog $inline$x_n(t)=u(t)$inline$. Tom qab ntawd ntawm lub receiver, lub teeb liab tau txais los ntawm n-th caij tuaj yeem sawv cev rau hauv daim ntawv:
$$display$$a_n(t) = u(t-tau_n)e^{i2pi f_0(t-tau_n)}$$display$$
qhov twg $inline$tau_n$inline$ yog qhov ncua sij hawm nyob rau hauv lub teeb liab propagation ntawm lub kav hlau txais xov caij mus rau qhov chaw txais.
Xws li lub teeb liab yog "quasi-harmonic", thiab kom ua tau raws li qhov kev sib raug zoo, nws yog qhov tsim nyog tias qhov kev ncua ntev tshaj plaws hauv kev nthuav tawm ntawm cov hluav taws xob hluav taws xob ntawm ob lub ntsiab lus yog tsawg dua li lub sijhawm hloov pauv ntawm lub teeb liab lub hnab ntawv $ inline$ T$ inline$, i.e. $inline$u(t-tau_n) ≈ u(t-tau_m)$inline$. Yog li, cov xwm txheej rau kev sib koom ua ke ntawm lub teeb liab nqaim tuaj yeem sau tau raws li hauv qab no:
$$display$$T≈frac{1}{Delta f}>>frac{D_{max}}{c}=max(tau_k-tau_m) $$display$$
qhov twg $inline$D_{max}$inline$ yog qhov siab tshaj plaws ntawm AR ntsiab lus, thiab $inline$с$inline$ yog qhov ceev ntawm lub teeb.
Thaum lub teeb liab tau txais, coherent summation yog ua digitally nyob rau hauv lub spatial processing unit. Hauv qhov no, tus nqi nyuaj ntawm cov teeb liab digital ntawm qhov tso tawm ntawm qhov thaiv no yog txiav txim siab los ntawm kev qhia:
$$display$$y=sum_{n=1}^Nw_n^*x_n$$display$$
Nws yog qhov yooj yim dua los sawv cev rau cov lus qhia kawg hauv daim ntawv N-dimensional complex vectors nyob rau hauv daim ntawv matrix:
$$display$$y=(textbf{w},textbf{x})=textbf{w}^Htextbf{x}$$display$$
qhov twg w и x yog kab vectors, thiab $inline$..)^H$inline$ yog qhov ua haujlwm .
Vector sawv cev ntawm cov teeb liab yog ib qho tseem ceeb thaum ua haujlwm nrog kav hlau txais xov arrays, vim feem ntau tso cai rau koj kom tsis txhob cumbersome lej suav. Tsis tas li ntawd, kev txheeb xyuas lub teeb liab tau txais nyob rau hauv ib lub sij hawm nyob rau hauv lub sij hawm nrog ib tug vector feem ntau tso cai rau ib tug kom paub daws teeb los ntawm lub cev tiag tiag system thiab to taub dab tsi raws nraim yog tshwm sim los ntawm qhov pom ntawm geometry.
Txhawm rau xam cov qauv hluav taws xob ntawm tus kav hlau txais xov array, koj yuav tsum xav thiab ua raws li "lav" txheej ntawm los ntawm txhua qhov ua tau. Hauv qhov no, qhov tseem ceeb ntawm cov ntsiab lus vector x tuaj yeem sawv cev rau hauv daim ntawv hauv qab no:
$$display$$x_n=s_n=exp{-i(textbf{k}(phi,theta),textbf{r}_n)}$$display$$
qhov twg k - , $inline$phi$inline$ thiab $inline$theta$inline$ – и , characterizing cov kev taw qhia ntawm kev tuaj txog ntawm ib lub dav hlau nthwv dej, $inline$textbf{r}_n$inline$ yog qhov kev sib koom tes ntawm cov kav hlau txais xov, $inline$s_n$inline$ yog lub caij ntawm phasing vector s dav hlau wave nrog wave vector k (hauv lus Askiv cov ntaub ntawv phasing vector yog hu ua steerage vector). Nyob ntawm qhov squared amplitude ntawm qhov ntau y los ntawm $inline$phi$inline$ thiab $inline$theta$inline$ txiav txim cov qauv hluav taws xob ntawm tus kav hlau txais xov array rau kev txais tos rau ib qho vector ntawm qhov hnyav coefficients w.
Nta ntawm tus kav hlau txais xov array hluav taws xob qauv
Nws yog qhov yooj yim los kawm txog cov yam ntxwv ntawm cov qauv hluav taws xob ntawm cov kav hlau txais xov arrays ntawm cov kab hluav taws xob sib npaug ntawm cov kav hlau txais xov hauv kab rov tav (piv txwv li, tus qauv nyob ntawm lub kaum ntse ntse azimuthal $ inline$ phi$ inline$). Yooj yim los ntawm ob lub ntsiab lus ntawm kev pom: analytical xam thiab kev nthuav qhia pom.
Cia peb suav DN rau ib chav ntsuas qhov hnyav ($inline$w_n=1, n = 1 ... N$inline$), raws li tau piav qhia mus kom ze.
lej ntawm no
Qhov projection ntawm yoj vector mus rau qhov ntsug axis: $inline$k_v=-frac{2pi}{lambda}sinphi$inline$
Vertical coordinate of the antenna element with index n: $inline$r_{nv}=(n-1)d$inline$
nws yog d - kav hlau txais xov array lub sij hawm (qhov deb ntawm cov khoom nyob ib sab), λ - wavelength. Tag nrho lwm yam vector ntsiab r yog sib npaug rau xoom.
Lub teeb liab tau txais los ntawm tus kav hlau txais xov array yog kaw rau hauv daim ntawv hauv qab no:
$$display$$y=sum_{n=1}^{N}1 ⋅exp{i2pi nfrac{d}{lambda}sinphi}$$display$$
Cia peb siv tus qauv rau и :
$$display$$y=frac{1-exp{i2pi Nfrac{d}{lambda}sinphi}}{1-exp{i2pi frac{d}{lambda}sinphi}}=frac{sin(pi frac{Nd} {lambda}sinphi)}{sin(pi frac{d}{lambda}sinphi)}exp{ipi frac{d(N-1)}{lambda}sinphi}$$display$$
Raws li qhov tshwm sim peb tau txais:
$$display$$F(phi)=|y|^2=frac{sin^2(pi frac{Nd}{lambda}sinphi)}{sin^2(pi frac{d}{lambda}sinphi)}$ $ zaub $$
Ntau zaus ntawm cov qauv hluav taws xob
Qhov tshwm sim ntawm tus kav hlau txais xov array hluav taws xob qauv yog lub sijhawm ua haujlwm ntawm lub sine ntawm lub kaum sab xis. Qhov no txhais tau hais tias ntawm qee qhov tseem ceeb ntawm qhov piv d/λ nws muaj diffraction (ntxiv) maxima.
Tsis yog-tus qauv hluav taws xob qauv ntawm tus kav hlau txais xov array rau N = 5
Cov qauv hluav taws xob zoo li qub ntawm tus kav hlau txais xov array rau N = 5 nyob rau hauv lub polar coordinate system
Txoj hauj lwm ntawm "diffraction detectors" tuaj yeem saib ncaj qha los ntawm rau DN. Txawm li cas los xij, peb yuav sim nkag siab qhov twg lawv tuaj ntawm lub cev thiab geometrically (hauv N-dimensional qhov chaw).
Cov khoom vector s yog complex exponents $inline$e^{iPsi n}$inline$, qhov tseem ceeb uas yog txiav txim los ntawm tus nqi ntawm lub generalized kaum $inline$Psi = 2pi frac{d}{lambda}sinphi$inline$. Yog tias muaj ob lub kaum ntse ntse sib txuas rau cov lus qhia sib txawv ntawm kev tuaj txog ntawm lub dav hlau nthwv dej, uas yog $ inline$ Psi_1 = Psi_2 + 2pi m$ inline$, ces qhov no txhais tau tias ob yam:
- Lub cev: Lub dav hlau nthwv dej pem hauv ntej los ntawm cov lus qhia no ua rau muaj qhov sib npaug ntawm qhov sib npaug-theem faib ntawm electromagnetic oscillations ntawm cov ntsiab lus ntawm cov kav hlau txais xov array.
- Geometrically: rau ob qho kev qhia no coincide.
Cov lus qhia ntawm nthwv dej tuaj txog ntawm txoj kev no yog sib npaug los ntawm qhov pom ntawm tus kav hlau txais xov array thiab yog qhov sib txawv ntawm ib leeg.
Yuav ua li cas txiav txim siab thaj tsam ntawm cov ces kaum uas tsuas yog ib qho loj tshaj plaws ntawm DP ib txwm dag? Cia peb ua qhov no nyob ib puag ncig ntawm xoom azimuth los ntawm cov kev xav hauv qab no: qhov loj ntawm theem hloov ntawm ob lub ntsiab lus uas nyob ib sab yuav tsum nyob hauv thaj tsam ntawm $inline$-pi$inline$ mus rau $inline$pi$inline$.
$$display$$-pi<2pifrac{d}{lambda}sinphi
Kev daws qhov tsis sib xws, peb tau txais cov xwm txheej rau thaj tsam ntawm qhov tsis sib xws hauv thaj tsam ntawm xoom:
$$ zaub$$|sinphi|
Nws tuaj yeem pom tau tias qhov loj ntawm thaj tsam ntawm qhov tsis sib xws hauv lub kaum sab xis nyob ntawm qhov kev sib raug zoo d/λ. yog hais tias d = 0.5λ, tom qab ntawd txhua qhov kev taw qhia ntawm cov teeb liab tuaj txog yog "tus kheej", thiab thaj tsam ntawm qhov tsis sib xws npog tag nrho cov kaum sab xis. Yog d = 2.0λ, ces cov lus qhia 0, ± 30, ± 90 yog sib npaug. Diffraction lobes tshwm rau ntawm cov qauv hluav taws xob.
Feem ntau, diffraction lobes yog nrhiav kom tau suppressed siv cov kav hlau txais xov qhia cov ntsiab lus. Nyob rau hauv cov ntaub ntawv no, tag nrho cov hluav taws xob qauv ntawm lub kav hlau txais xov array yog cov khoom ntawm cov qauv ntawm ib lub caij thiab ib tug array ntawm isotropic ntsiab. Cov tsis muaj tus qauv ntawm ib lub caij feem ntau yog xaiv raws li cov xwm txheej rau thaj tsam ntawm unambiguity ntawm tus kav hlau txais xov array.
Main lobe dav
engineering formula rau kwv yees qhov dav ntawm lub ntsiab lobe ntawm lub kav hlau txais xov system: $inline$Delta phi ≈ frac{lambda}{D}$inline$, qhov twg D yog tus yam ntxwv loj ntawm tus kav hlau txais xov. Cov mis yog siv rau ntau hom kav hlau txais xov, nrog rau daim iav. Cia peb qhia tias nws tseem siv tau rau cov kav hlau txais xov arrays.
Cia peb txiav txim siab qhov dav ntawm lub ntsiab lobe los ntawm thawj xoom ntawm cov qauv nyob ib puag ncig ntawm qhov siab tshaj plaws. Tus lej rau $inline$F(phi)$inline$ ploj mus thaum $inline$sinphi=mfrac{lambda}{dN}$inline$. Thawj zeros sib raug rau m = ± 1. $inline$frac{lambda}{dN}<<1$inline$ peb tau $inline$Delta phi = 2frac{lambda}{dN}$inline$.
Feem ntau, qhov dav ntawm tus kav hlau txais xov ncaj qha qauv yog txiav txim siab los ntawm ib nrab lub zog (-3 dB). Hauv qhov no, siv cov lus qhia:
$$display$$Delta phi≈0.88frac{lambda}{dN}$$display$$
Piv Txwv:
Qhov dav ntawm lub ntsiab lobe tuaj yeem tswj tau los ntawm kev teeb tsa qhov sib txawv amplitude qhov tseem ceeb rau cov kav hlau txais xov array qhov hnyav coefficients. Cia peb xav txog peb qhov kev faib tawm:
- Uniform amplitude distribution (qhov hnyav 1): $inline$w_n=1$inline$.
- Amplitude qhov tseem ceeb txo qis ntawm cov npoo ntawm cov grating (qhov hnyav 2): $inline$w_n=0.5+0.3cos(2pifrac{n-1}{N}-pifrac{N-1}{N})$inline$
- Amplitude qhov tseem ceeb nce rau ntawm cov npoo ntawm cov grating (qhov hnyav 3): $inline$w_n=0.5-0.3cos(2pifrac{n-1}{N}-pifrac{N-1}{N})$inline$
Daim duab qhia tau hais tias cov qauv hluav taws xob zoo li qub ntawm qhov ntsuas logarithmic:
Cov qauv hauv qab no tuaj yeem taug qab los ntawm daim duab: qhov sib faib ntawm qhov hnyav coefficient amplitudes txo qis ntawm cov npoo ntawm cov array ua rau kev nthuav dav ntawm lub ntsiab lobe ntawm tus qauv, tab sis qhov txo qis ntawm qib ntawm sab lobes. Amplitude qhov tseem ceeb nce mus rau cov npoo ntawm cov kav hlau txais xov array, ntawm qhov tsis sib xws, ua rau kom nqaim ntawm lub ntsiab lobe thiab nce qib ntawm sab lobes. Nws yog qhov yooj yim los txiav txim siab txwv cov xwm txheej ntawm no:
- Lub amplitudes ntawm qhov hnyav coefficients ntawm tag nrho cov ntsiab tsuas yog cov huab sawv daws yuav sib npaug zos rau xoom. Qhov hnyav rau cov ntsiab lus sab nraud yog sib npaug rau ib qho. Nyob rau hauv rooj plaub no, lub lattice yuav sib npaug rau ob lub ntsiab lus AR nrog lub sijhawm D = (N-1)d. Nws tsis yog nyuaj rau kwv yees qhov dav ntawm lub ntsiab petal siv cov mis uas tau hais los saum toj no. Nyob rau hauv cov ntaub ntawv no, lub sidewalls yuav tig mus rau hauv diffraction maxima thiab ua raws li lub ntsiab siab tshaj plaws.
- Qhov hnyav ntawm lub hauv paus ntsiab lus yog sib npaug rau ib qho, thiab tag nrho lwm tus yog sib npaug rau xoom. Hauv qhov no, peb yeej ib txwm tau txais ib lub kav hlau txais xov nrog cov qauv hluav taws xob isotropic.
Kev taw qhia ntawm lub ntsiab siab tshaj plaws
Yog li, peb tau saib yuav ua li cas koj tuaj yeem kho qhov dav ntawm lub ntsiab lobe ntawm AP AP. Tam sim no cia saib yuav ua li cas coj txoj kev taw qhia. Cia peb nco ntsoov rau lub teeb liab tau txais. Cia peb xav kom qhov siab tshaj plaws ntawm cov qauv hluav taws xob saib hauv ib qho kev taw qhia $inline$phi_0$inline$. Qhov no txhais tau hais tias lub zog siab tshaj plaws yuav tsum tau txais los ntawm qhov kev taw qhia no. Qhov kev taw qhia no sib raug rau phasing vector $inline$textbf{s}(phi_0)$inline$ hauv N-dimensional vector qhov chaw, thiab lub hwj chim tau txais yog txhais raws li lub square ntawm cov khoom scalar ntawm no phasing vector thiab vector ntawm qhov hnyav coefficients w. Cov khoom scalar ntawm ob vectors yog qhov siab tshaj plaws thaum lawv , i.e. $inline$textbf{w}=beta textbf{s}(phi_0)$inline$, qhov twg β - ib co normalizing factor. Yog li, yog tias peb xaiv qhov hnyav vector sib npaug rau phasing vector rau qhov xav tau kev taw qhia, peb yuav tig qhov siab tshaj plaws ntawm cov qauv hluav taws xob.
Xav txog qhov hnyav hauv qab no ua piv txwv: $inline$textbf{w}=textbf{s}(10°)$inline$
$$display$$w_n=exp{i2pifrac{d}{lambda}(n-1)sin(10pi/180)}$$display$$
Yog li ntawd, peb tau txais cov qauv hluav taws xob nrog qhov siab tshaj plaws nyob rau hauv kev coj ntawm 10 °.
Tam sim no peb siv tib qhov hnyav coefficients, tab sis tsis yog rau kev txais lub teeb liab, tab sis rau kev sib kis. Nws yog ib qho tsim nyog xav txog ntawm no tias thaum xa cov teeb liab, cov kev taw qhia ntawm yoj vector hloov mus rau qhov tsis sib xws. Qhov no txhais tau tias cov ntsiab lus rau kev txais tos thiab kev sib kis lawv txawv ntawm qhov kos npe ntawm tus exponent, i.e. yog interconnected los ntawm complex conjugation. Raws li qhov tshwm sim, peb tau txais qhov siab tshaj plaws ntawm cov qauv hluav taws xob xa mus rau qhov kev taw qhia ntawm -10 °, uas tsis sib haum nrog qhov siab tshaj plaws ntawm cov qauv hluav taws xob rau kev txais tos nrog tib qhov hnyav coefficients. siv complex conjugation rau qhov hnyav coefficients thiab.
Cov lus piav qhia ntawm kev tsim cov qauv rau kev txais tos thiab kev sib kis yuav tsum nco ntsoov khaws cia hauv siab thaum ua haujlwm nrog cov kav hlau txais xov arrays.
Cia peb ua si nrog cov qauv hluav taws xob
Ob peb siab
Cia peb teeb tsa txoj haujlwm ntawm kev tsim ob lub ntsiab ntawm cov qauv hluav taws xob nyob rau hauv cov kev taw qhia: -5 ° thiab 10 °. Ua li no, peb xaiv raws li qhov hnyav vector qhov hnyav ntawm phasing vectors rau cov lus qhia sib xws.
$$display$$textbf{w} = betatextbf{s}(10°)+(1-beta)textbf{s}(-5°)$$display$$
Kho qhov piv txwv β Koj tuaj yeem kho qhov sib piv ntawm lub ntsiab petals. Ntawm no dua nws yog qhov yooj yim los saib dab tsi tshwm sim hauv vector chaw. Yog β yog ntau dua 0.5, ces cov vector ntawm qhov hnyav coefficients nyob ze rau s(10 °), txwv tsis pub s(-5 °). Qhov ze dua qhov hnyav vector yog rau ib qho ntawm phasors, ntau dua cov khoom siv scalar, thiab yog li ntawd tus nqi ntawm qhov sib thooj siab tshaj DP.
Txawm li cas los xij, nws tsim nyog xav tias ob lub ntsiab lus tseem ceeb muaj qhov dav dav, thiab yog tias peb xav qhib rau ob qho kev qhia ze, ces cov petals yuav sib koom ua ib qho, taw qhia rau qee qhov nruab nrab.
Ib qhov siab tshaj plaws thiab xoom
Tam sim no cia peb sim kho qhov siab tshaj plaws ntawm cov qauv hluav taws xob mus rau qhov kev taw qhia $inline$phi_1=10°$inline$ thiab tib lub sij hawm txwv tsis pub lub teeb liab los ntawm kev taw qhia $inline$phi_2=-5°$inline$. Txhawm rau ua qhov no, koj yuav tsum teeb tsa DN xoom rau lub kaum sab xis. Koj tuaj yeem ua qhov no raws li hauv qab no:
$$display$$textbf{w}=textbf{s}_1-frac{textbf{s}_2^Htextbf{s}_1}{N}textbf{s}_2$$display$$
qhov twg $inline$textbf{s}_1 = textbf{s}(10°)$inline$, thiab $inline$textbf{s}_2 = textbf{s}(-5°)$inline$.
Lub ntsiab lus geometric ntawm kev xaiv ib qho hnyav vector yog raws li hauv qab no. Peb xav tau cov vector no w muaj qhov projection siab tshaj plaws rau $inline$textbf{s}_1$inline$ thiab yog tib lub sijhawm orthogonal rau vector $inline$textbf{s}_2$inline$. Tus vector $inline$textbf{s}_1$inline$ tuaj yeem sawv cev ua ob nqe lus: ib qho kev sib koom ua ke vector $inline$textbf{s}_2$inline$ thiab ib qho orthogonal vector $inline$textbf{s}_2$inline$. Txhawm rau kom txaus siab rau cov lus hais txog qhov teeb meem, nws yog ib qho tsim nyog los xaiv qhov thib ob raws li vector ntawm qhov hnyav coefficients w. Cov khoom sib xyaw ua ke tuaj yeem suav tau los ntawm qhov projecting vector $inline$textbf{s}_1$inline$ mus rau qhov qub vector $inline$frac{textbf{s}_2}{sqrt{N}}$inline$ siv cov khoom scalar.
$$display$$textbf{s}_{1||}=frac{textbf{s}_2}{sqrt{N}}frac{textbf{s}_2^Htextbf{s}_1}{sqrt{N}} $$ display$$
Raws li, rho tawm nws cov collinear tivthaiv los ntawm thawj phasing vector $inline$textbf{s}_1$inline$, peb tau txais qhov hnyav vector.
Qee cov ntawv sau ntxiv
- Txhua qhov chaw saum toj no, kuv tshem tawm qhov teeb meem ntawm normalizing qhov hnyav vector, i.e. nws ntev. Yog li, normalization ntawm qhov hnyav vector tsis cuam tshuam rau cov yam ntxwv ntawm tus kav hlau txais xov array hluav taws xob qauv: cov kev taw qhia ntawm qhov siab tshaj plaws, qhov dav ntawm lub ntsiab lobe, thiab lwm yam. Nws tseem tuaj yeem pom tau tias qhov normalization no tsis cuam tshuam rau SNR ntawm cov khoom tsim tawm ntawm qhov chaw ua haujlwm spatial. Nyob rau hauv no hais txog, thaum xav txog spatial teeb liab ua algorithms, peb feem ntau txais ib chav tsev normalization ntawm qhov hnyav vector, i.e. $inline$textbf{w}^Htextbf{w}=1$inline$
- Qhov muaj peev xwm tsim tau tus qauv ntawm tus kav hlau txais xov array yog txiav txim los ntawm tus naj npawb ntawm cov ntsiab lus N. Cov ntsiab lus ntau dua, qhov ntau dua qhov muaj peev xwm. Ntau qib ntawm kev ywj pheej thaum siv qhov hnyav hnyav, qhov kev xaiv ntau dua rau "twist" qhov hnyav vector hauv N-dimensional qhov chaw.
- Thaum tau txais cov qauv hluav taws xob, lub kav hlau txais xov array tsis muaj nyob hauv lub cev, thiab tag nrho cov no tsuas muaj nyob hauv "kev xav" ntawm lub tshuab xam zauv uas ua cov teeb liab. Qhov no txhais tau hais tias tib lub sijhawm nws muaj peev xwm ua kom muaj ntau yam qauv thiab nws tus kheej ua cov cim los ntawm ntau cov lus qhia. Nyob rau hauv cov ntaub ntawv ntawm kev sib kis, txhua yam yog me ntsis nyuab dua, tab sis nws kuj tseem tuaj yeem ua ke ntau DNs kom xa cov ntaub ntawv sib txawv. Lub tshuab no hauv kev sib txuas lus hu ua .
- Siv cov lus qhia matlab, koj tuaj yeem ua si nrog DN koj tus kheej
code% antenna array settings N = 10; % number of elements d = 0.5; % period of antenna array wLength = 1; % wavelength mode = 'receiver'; % receiver or transmitter % weights of antenna array w = ones(N,1); % w = 0.5 + 0.3*cos(2*pi*((0:N-1)-0.5*(N-1))/N).'; % w = 0.5 - 0.3*cos(2*pi*((0:N-1)-0.5*(N-1))/N).'; % w = exp(2i*pi*d/wLength*sin(10/180*pi)*(0:N-1)).'; % b = 0.5; w = b*exp(2i*pi*d/wLength*sin(+10/180*pi)*(0:N-1)).' + (1-b)*exp(2i*pi*d/wLength*sin(-5/180*pi)*(0:N-1)).'; % b = 0.5; w = b*exp(2i*pi*d/wLength*sin(+3/180*pi)*(0:N-1)).' + (1-b)*exp(2i*pi*d/wLength*sin(-3/180*pi)*(0:N-1)).'; % s1 = exp(2i*pi*d/wLength*sin(10/180*pi)*(0:N-1)).'; % s2 = exp(2i*pi*d/wLength*sin(-5/180*pi)*(0:N-1)).'; % w = s1 - (1/N)*s2*s2'*s1; % w = s1; % normalize weights w = w./sqrt(sum(abs(w).^2)); % set of angle values to calculate pattern angGrid_deg = (-90:0.5:90); % convert degree to radian angGrid = angGrid_deg * pi / 180; % calculate set of steerage vectors for angle grid switch (mode) case 'receiver' s = exp(2i*pi*d/wLength*bsxfun(@times,(0:N-1)',sin(angGrid))); case 'transmitter' s = exp(-2i*pi*d/wLength*bsxfun(@times,(0:N-1)',sin(angGrid))); end % calculate pattern y = (abs(w'*s)).^2; %linear scale plot(angGrid_deg,y/max(y)); grid on; xlim([-90 90]); % log scale % plot(angGrid_deg,10*log10(y/max(y))); % grid on; % xlim([-90 90]);
Cov teeb meem dab tsi tuaj yeem daws tau los ntawm kev siv lub kav hlau txais xov hloov kho?
Zoo txais tos ntawm lub teeb liab tsis paubYog hais tias qhov kev taw qhia ntawm kev tuaj txog ntawm lub teeb liab yog tsis paub (thiab yog hais tias tus channel kev sib txuas lus yog multipath, feem ntau muaj ob peb cov lus qhia), ces los ntawm kev soj ntsuam cov teeb liab tau txais los ntawm tus kav hlau txais xov array, nws yog ib qhov tsim nyog los tsim ib tug optimizing vector vector. w yog li ntawd SNR ntawm cov zis ntawm lub spatial processing unit yuav siab tshaj plaws.
Optimal teeb liab txais tos tiv thaiv lub suab nrov tom qabNtawm no qhov teeb meem yog posed raws li hauv qab no: lub spatial tsis ntawm qhov yuav tsum tau muaj txiaj ntsim teeb liab yog paub, tab sis muaj qhov chaw ntawm kev cuam tshuam nyob rau hauv lub sab nraud ib puag ncig. Nws yog ib qho tsim nyog los ua kom tiav qhov SINR ntawm AP cov zis, txo qis kev cuam tshuam ntawm cov teeb liab txais.
Optimal teeb liab kis tau tus mob rau tus neeg sivQhov teeb meem no daws tau hauv kev sib txuas lus hauv xov tooj (4G, 5G), nrog rau hauv Wi-Fi. Lub ntsiab lus yog yooj yim: nrog kev pab los ntawm tshwj xeeb pilot signals nyob rau hauv tus neeg siv tswv yim channel, spatial yam ntxwv ntawm kev sib txuas lus channel raug soj ntsuam, thiab nyob rau hauv nws lub hauv paus, lub vector ntawm weighting coefficients uas zoo rau kis tau tus mob yog xaiv.
Spatial multiplexing ntawm cov ntaub ntawv ntwsAdaptive antenna arrays tso cai rau cov ntaub ntawv xa mus rau ntau tus neeg siv tib lub sijhawm ntawm tib zaus, tsim ib tus qauv rau txhua tus ntawm lawv. Lub tshuab no hu ua MU-MIMO thiab tam sim no tau ua haujlwm nquag (thiab qee qhov twb tau lawm) hauv kev sib txuas lus. Qhov muaj peev xwm ntawm spatial multiplexing yog muab, piv txwv li, hauv 4G LTE mobile kev sib txuas lus tus qauv, IEEE802.11ay Wi-Fi tus qauv, thiab 5G mobile kev sib txuas lus qauv.
Virtual kav hlau txais xov arrays rau radarsCov kav hlau txais xov digital arrays ua rau nws ua tau, siv ob peb lub xaim xaim xaim xaim, los tsim ib lub kav hlau txais xov virtual ntawm qhov loj me me rau kev ua cov teeb liab. Ib daim phiaj virtual muaj tag nrho cov yam ntxwv ntawm ib qho tiag tiag, tab sis yuav tsum muaj cov khoom siv tsawg dua los siv.
Kev kwv yees qhov ntsuas ntawm qhov chaw hluav taws xobAdaptive kav hlau txais xov arrays tso cai daws qhov teeb meem ntawm kev kwv yees tus naj npawb, lub zog, qhov chaw ntawm xov tooj cua emission, tsim kom muaj kev sib txuas ntawm cov teeb liab los ntawm ntau qhov chaw. Lub ntsiab kom zoo dua ntawm adaptive kav hlau txais xov arrays nyob rau hauv qhov teeb meem no yog lub peev xwm los daws super daws teeb meem nyob ze qhov chaw. Qhov chaw, qhov kev ncua deb ntawm qhov tsawg dua qhov dav ntawm lub ntsiab lobe ntawm tus kav hlau txais xov array hluav taws xob qauv (). Qhov no feem ntau yog ua tau vim lub vector sawv cev ntawm lub teeb liab, tus qauv paub zoo ntawm cov teeb liab, nrog rau cov cuab yeej ntawm linear lej.
Ua tsaug rau koj kev paub.
Tau qhov twg los: www.hab.com