Performance Analysis of Atmospheric Field Conjugation Adaptive Arrays

Size: px
Start display at page:

Download "Performance Analysis of Atmospheric Field Conjugation Adaptive Arrays"

Transcription

1 Perforance Analysis of Atospheric Field Conjugation Adaptive Arrays Aniceto Belonte* a, Joseph M. Kahn b a Technical Univ. of Catalonia, Dept. of Signal Theory and Coun., Barcelona, Spain; b Stanford University, Departent of Electrical Engineering, Stanford, CA 94305, USA * belonte@tsc.upc.edu ABSTRACT Syste configurations based on single onolithic-apertures that are iune to atospheric fluctuations are being developed. Main goal is the iproveent of the perforance achievable in coherent, free-space optical counication systes using atospheric copensation techniques such as adaptive optics. As an alternative to a single onolithicaperture coherent receiver with a full-size collecting area, a large effective aperture can be achieved by cobining the output signal fro an array of saller receivers. We study the counication perforance of field conjugation adaptive arrays applied in synchronous laser counication through the turbulent atosphere. We assue that a single inforation-bearing signal is transitted over the atospheric fading channel, and that the adaptive array coherent receiver cobines ultiple dependent replicas to iprove detection efficiency. We consider the effects of log-noral aplitude fluctuations and Gaussian phase fluctuations, in addition to local oscillator shot noise. We study the effect of various atospheric paraeters and the nuber of branches cobined at the receiver. Keywords: Atospheric optical counications; Coherent receivers; Diversity cobining 1. INTRODUCTION With coherent counications, the coplex field of the received signal encodes the transitted inforation. To fully easure the coplex electrical field, i.e. aplitude and phase, of the light wave, in a coherent detection syste the incoing signal interferes with a local oscillator (LO). In a free-space laser receiver the presence of atospheric turbulence affects the coherence of the received signal that is to be ixed with the local oscillator. Light propagated through a turbulent atosphere contains speckle which will be present at the detector surface. Therefore, illuinating a single-eleent detector with a unifor LO bea will produce isatch of the aplitudes and phases of the two fields resulting in a loss in downconverted power. The downconverted coherent power is axiized when the spatial field of the received signal atches that of the local oscillator. [1],[] Syste configurations based on single onolithic-apertures that are iune to atospheric fluctuations are being developed. [3] Main goal is the iproveent of the perforance achievable in coherent, free-space optical counication systes using atospheric copensation techniques. As an alternative to this approach, the perforance of diversity cobining techniques, where two or ore statistically independent fading signals are cobined at the receiver, have been considered to iprove detection efficiency in coherent laser counication through the turbulent atosphere. [4][5] Diversity cobining consists of receiving redundantly the sae inforation signal over ultiple fading channels and to exploit the low probability of concurrence of deep fades in all the diversity channels. In this analysis, we consider a coherent fiber array consisting of densely packet ultiple subapertures, with each subaperture interfaced to a single-ode fiber, as a receiver structure for increasing the perforance of the atospheric laser syste. Instead of using a single onolithic-aperture coherent receiver with a full-size collecting area, a large effective aperture can be equally achieved by cobining the output signal fro a fiber array of saller subapertures in a close-packed arrangeent (see Fig. 1). A coherent fiber array offers an advantage in ters of the coupling efficiency as that the nuber of turbulence speckles over each subaperture in the array is uch saller than it would be over a single large aperture. Now, each receiver aperture can be saller than the scale on which the signal wavefront varies and the local oscillator phase can be atched to the signal to attain successful coherent reception. Output signals fro these receivers can then be cobined electronically to enhance the detection statistics. In general, the perforance of such a field conjugation adaptive should iprove with an increasing nuber of subapertures and, given a fixed collecting area, Free-Space Laser Counication Technologies XXIII, edited by Haid Heati, Proc. of SPIE Vol. 793, 7930Q 011 SPIE CCC code: X/11/$18 doi: / Proc. of SPIE Vol Q-1 Downloaded fro SPIE Digital Library on Feb 011 to Ters of Use:

2 the fiber array syste can offer superior perforance. Note that, due to the close spatial arrangeent of the subapertures in a coherent fiber array, atospheric fading on the array coponents is correlated or dependent. We consider a general statistical odel to describe the signal collected by the fiber array receiver after propagation through the atosphere. We consider the perforance of such receivers under the effects of log-noral aplitude fluctuations and Gaussian phase fluctuations, in addition to local oscillator shot noise.. A STATISTICAL MODEL FOR THE RECEIVER In a coherent counication receiver, the SNR γ 0 per unit bandwidth B for a quantu or shot-noise liited signal can be interpreted as the detected nuber of photons (photocounts) per sybol when 1/B is the sybol period. Coherently detected signals are odeled as narrowband RF signals with additive white Gaussian noise (AWGN). For a coherent receiver syste, in the presence of target speckle and atospheric turbulence, we ust consider fading signals, which are signals also affected by ultiplicative noise. In the fading AWGN channel, we let α denote the atospheric channel power fading and γ 0 α denote the instantaneous received SNR per pulse. For a shot-noise-liited coherent optical receiver, the SNR of the envelope detector can be taken as the nuber of signal photons detected on the receiver aperture γ 0 ultiplied by a heterodyne power ixing efficiency α. For systes with perfect spatial ode atching, the ixing efficiency is equal to 1. When the spatial odes are not properly atched, the contribution to the current signal fro different parts of the receiver aperture can interfere destructively and result in the reduced instantaneous heterodyne ixing and consequent fading. Note that, conditional on a realization of the atospheric channel described by α, this is an AWGN channel with instantaneous received SNR γ=γ 0 α. This quantity is a function of the rando channel power fading α, and is therefore rando. The statistical properties of the atospheric rando channel fade α, with probability density function (PDF) p α (α), provide a statistical characterization of the SNR γ=γ 0 α. In this study we define a statistical odel for the fading aplitude α (i.e., SNR γ) of the received signal after propagation through the atosphere. In a single-aperture, fiber-based coherent receiver, when the spatial field of the received signal E i (r) does not atch that of the local oscillator E (r), as described by the fiber-ode profile referred to the receiving aperture, the rando fading 4 α = d W ( ) Ei( ) E( ) π D r r r r (1) depends in aplitude and phase isatches of the two fields incident on the receiving aperture. Phase and aplitude isatches represent the aplitude fluctuations and phase distortions introduced by atospheric turbulence in the received signal. The circular receiving aperture of diaeter D is defined by the aperture function W(r), which equals unity for r D/, and equals zero for r >D/. In general, in Eq. (1) fading is a coplex agnitude α = αr + jαiwhere α r and α i represent integrals over the collecting aperture of the real and iaginary parts, respectively, of the optical fields reaching the receiver. These real and iaginary parts can be considered as the coponents of a coplex rando phasor. We need to study how aplitude and phase turbulence-induced fluctuations of the optical field define the statistics of the fading intensity α = αr + jαi. Fro Eq. (1), we note that the two rando agnitudesα r and α i can be expressed as integrals over the aperture and, hence, are the sus of contributions fro each point in the aperture. In order to proceed with the analysis, we could consider a statistical odel in which these continuous integrals are expressed as finite sus over statistically independent cells in the aperture. Under the assuption that the nuber of independent coherent regions is large enough, we can consider that α r and α i asyptotically approach jointly noral rando variables. Then, the probability density function of the length fading aplitude α can be well approxiate by a Rayleigh distribution. Just as in a speckle pattern, the Rayleigh distribution for the turbulence aplitude fading length is a consequence of the central-liit theore. However, under conditions of weak-turbulence in which the nuber of coherent ters is sall, the fading ay actually be the result of suing a sall nuber of ters. In this case, the fading α is not likely to be Rayleigh. Rather than assuing that α is always Rayleigh distributed for all conditions of turbulence, it is ore realistic to assue that α satisfied a generalized Rayleigh distribution that becoes Rayleigh only when the nuber of coherent ters N becoes large enough. Such a distribution is the Nakagai- distribution, [6] in essence a central chi-square distribution described by: Proc. of SPIE Vol Q- Downloaded fro SPIE Digital Library on Feb 011 to Ters of Use:

3 1 α pα ( α ) = ( N) exp N Γ ( ) ( α ). () where Γ is the coplete gaa function. The Nakagai- paraeter and fading paraeter N are a easure of turbulence effects. Here, N is the inverse of the fading ean-square value N = 1 α. (3) The paraeter characterizes the aount of turbulent fading. When 1, the nuber of contribution coherent areas N is large and the -distribution reduces to Rayleigh. Note that the Nakagai- distribution closely approxiates the Rice distribution [6] we have previously used to odel the ipact of atospheric turbulence-induced fading on free-space optical counication links using coherent detection. [3] Applying the Jacobian of the transforation α = γ γ0, the corresponding SNR γ distribution can be described according to a gaa distribution with a shape paraeter and a ean value γ = γ α γ given by 0 0 N p γ ( γ) 1 N γ N = exp γ. (4) γ Γ γ ( ) 0 0 When 1, the gaa distribution reduces to exponential distribution. Note that the PDF in Eq. (4) can equivalently be expressed in ters of its oent generating function (MGF), which it is closely related to the Laplace transfor of the distribution p γ ( γ ) and defined as the expected value of exp( sγ ) : ( ) = γ exp( γ) γ ( γ) M s d s p γ 0 γ0 γ0 1 s 1 s. = = α N The MGF is a useful tool for analyzing the average error probability in counication systes with fading. Also, it can be shown that the distribution oents are given by k γ ( k) k Γ( ) Γ + = which yields, by using the average SNR, an expression for (5) k γ, (6) 4 1 σ γ α = = 1. (7) γ α Since α r and α i can be considered jointly noral rando variables, it is possible to relate high-order oents with the 4 4 lower-order oents and replaces the fourth-order oent in Eq. (7) by α = 3α α. It results: 1 α =. (8) α The paraeter, by characterizing the aount of fading through the noralized SNR γ variance, gives ore control over the extent of the turbulence fading. When 1 and the nuber of contribution coherent areas is large, the noralized variance is one, as expected for Rayleigh distributions. When grows, and a very sall nuber of contribution ters add together, the noralized variance decreases. Now, the density function becoes highly peaked around the ean value γ = γ 0 N and there is just a sall fading to be considered. To have a easure of turbulence effects, it has been necessary to develop procedures to estiate and N. Equivalently, as Eqs. (3) and (8) describe fading paraeters and N in ters of fading first and second oents, we have needed to Proc. of SPIE Vol Q-3 Downloaded fro SPIE Digital Library on Feb 011 to Ters of Use:

4 establish closed expressions for α and α. In order to assess the ipact of turbulence on the heterodyne ixing and fading, the field aplitude without the effect of turbulence in the pupil plane ust be odified by a ultiplicative factor exp χ( r) jφ( r) where χ(r) and φ(r) represent the log-aplitude fluctuations (scintillation) and phase variations (aberrations), respectively, introduced by atospheric turbulence. Consequently, both γ and 1/r are described in ters of log-noral aplitude fluctuations and Gaussian phase fluctuations as characterized by their respective statistical variances, σ χ and σ φ. Also, the propagating ode of a single-ode fiber is well approxiated by an untruncated Gaussian function and the fiber-ode profile referred to the receiving aperture describing the local oscillator E (r) can be characterized by its fiber-ode field radius at the front surface of the receiving lens ω. We define a general odel for the output SNR of diversity systes over correlated fading channels. For field conjugation adaptive arrays, where the atospheric fading on the branches is correlated or dependent, we can solve the proble by transforing it into an independent proble using the technique of spatial whitening. At this way, the results for independent fading channels are easily extended to the ore general proble of correlated channels. 3. PERFORMANCE OF A CLOSELY PACKED HEXAGONAL COHERENT ARRAY In a field conjugation fiber array, the interediate-frequency signals at the output of the single-ode fibers needs to be co-phased and their aplitude independently adapted before they are sued to lessen signal fading associated with atospheric turbulence and reduce fiber coupling shortcoings. Note that this is equivalent to consider axiu ratio cobining (MRC) of the received signals by the array subapertures as they can be considered as branches of a diversity cobiner. [7] MRC diversity schees assue perfect knowledge of the branch aplitudes and phases, require independent processing of each branch, and need that the individual signals fro each branch be weighted by their signal to noise power ratios then sued coherently. A receiver with MRC will coherently cobine the diversity branches by weighting the by the coplex conjugate of their respective fading gains and adding the. Clearly, like in a MRC cobiner, the instantaneous SNR γ T for a suing coherent array is the power ratio of the phase-coherent addition of the signal aplitudes fro each eleent of the array to the incoherent addition of the noise. If an optiu voltage gain proportional to the aplitude of the signal itself is assued for each eleent in the array, and if equal noise powers are assued, the resultant coposite SNR γ T for an L-eleent coherent fiber array is the su of the array eleents SNR γ l. For independent subaperture signals and equal average branch SNR, i.e. γl = γ for all l {1,,,L}, the PDF of the received SNR γ T at the output of a perfect L-branch coherent array in the atosphere would be described a su of L independent and identically distributed gaa rando variables. This rando variable it is also described by the gaa distribution Eq. (4) with a shape paraeter (L). However, for close coherent fiber arrays receivers, with insufficient collecting apertures spacing, it is not realistic to assue that the cobined signals are independent of one another. In this scenario, the degree of correlation aong the different fadingsα l describing γ T will depend on several factors, including atospheric conditions and the exact geoetry of the coherent array receiver. It is worthy of entioning that the evaluation of the ost coon perforance easures of an optical coherent counication syste in the presence of atospheric fading can be accoplished based entirely on the knowledge of the MGF of the output SNR without ever having to copute its PDF. We will use MT ( s ) to estiate the perforance of the MRC coherent fiber array. This MGF-based approach is quite useful in siplifying our analysis. Figures 3 and 4 consider the ean and standard deviation of the SNR at the output of field conjugation adaptive arrays. We conteplate an L-eleent coherent fiber array and assue that the subapertures are arranged in a hexagonal closepacked array as shown in Fig.. The larger circle represents a single receiver aperture of diaeter D. The sall circles represent packed subapertures and each subaperture contains a lens that couples the received light into a single-ode fiber. For coparison of the receiver perforance between an L-eleent coherent array and a single large aperture, we force the hexagonal array to be packed within the liits of the single aperture area. The hexagonal distribution is the densest way to arrange circles in a plane. Still, note that each subaperture will have a pupil area slightly saller than 1/L ties the pupil area of the single receiver syste and an array fill factor needs to be considered in our analysis. For instances, for the array with L=7 eleents in Fig. 1, the array fill factor is 7/9. Also, the truncation paraeter of the pupil τ D ω describes the ratio of the receiver aperture diaeter to the diaeter of the backpropagated fiber ode. A large Proc. of SPIE Vol Q-4 Downloaded fro SPIE Digital Library on Feb 011 to Ters of Use:

5 value of τ or D ω represents a narrow Gaussian ode or a weakly truncated pupil. A unifor illuinated pupil is obtained by letting τ 0. The truncation paraeter ust be chosen to optiize the receiving syste perforance. Although the optiu paraeter ay depend on the level of atospheric turbulence considered, this dependency is very weak and we can chose the optiu value of 1.1 obtained in absence of turbulence, when the incident plane wave is fully coherent. [8] We study the ean SNR in Fig. 3 and the SNR noralized standard deviation in Fig. 4 as a function of several paraeters: the average turbulence-free SNR γ 0, the receiver aperture diaeter D, the nuber of subapertures L of the hexagonal distributed fiber array coherently sued, and the strength of atospheric turbulence. Turbulence is quantified by two paraeters: the phase coherence length r 0, which describes the spatial correlation of phase fluctuations in the receiver plane, [1] and the scintillation index σ β. [9] The value of the scintillation index σ β = 1 corresponds to strong scintillation, but still below the saturation regie. When we assue no scintillation, σ β =0, the effect of turbulence is siply to reduce the coherence length r 0. For a fixed coherent diaeter r 0, as aperture diaeter D is increased, the noralized aperture diaeter D/r 0 increases, and turbulence reduces the heterodyne downconversion efficiency. In Fig. 3, the ean SNR is plotted against the noralized aperture diaeter D/r 0 for different nuber of subapertures L on the hexagonal array. The SNR is expressed in db, referenced to the turbulence free SNR γ 0. This corresponds to the ean intensity fading α = 1 N according to the transforation γ = γα 0. Note that the ean SNR is just a representation of the fiber-coupling efficiency. The received signal bea ust be coupled into a single-ode fiber but atospheric turbulence degrades the spatial coherence of a laser bea and liits the fiber-coupling efficiency and, consequently, the available ean SNR at the output of each fiber in the array. As expected for one single onolithic aperture L=1, if D is less than r 0, the noralized ean SNR γ γ 0 reains constant. A truncation paraeter τ = 1.1 reduces the ean SNR by 5 db. When diaeter D is larger than r 0, atospheric turbulence liits the effective receiving aperture to the diensions of the coherence diaeter r 0 and the noralized ean SNR goes down very quickly. When the noralized aperture diaeter D/r 0 is large, an increase in the nuber of the hexagonal array subapertures iproves the situation significantly. For instances, when a large noralized aperture D/r 0 =10 is considered, increasing the nuber of subapertures L fro 1 to 19 coends the ean SNR by ore than 13 db. The ean SNR is just a representation of the fiber-coupling efficiency: the advantage of a fiber array in ters of the ean SNR and the fiber coupling efficiency is that the nuber of field coherence areas N over each subaperture is saller than it would be over a single large aperture. In Fig. 4, we plot the noralized SNR standard deviation (SNR uncertainty or relative error) σ γ γ against the noralized aperture diaeter D/r 0 for different values of the nuber of subapertures L on the hexagonal array. In the liit of weak turbulence (sall noralized aperture diaeter D/r 0 ), the noralized variance trends asyptotically to 0. When aperture diaeter is increased, SNR uncertainty grows steadily with the nuber of field coherence areas N over the receiving pupil until reaching a well define axi. In the liit of strong turbulence (large noralized aperture diaeter D/r 0 ), the SNR uncertainty becoes flat and very intense. When L=1, the SNR standard deviation reach a axiu value of alost 1.6 ( db). Once again, an increase in the nuber of the array subapertures will iprove the situation and decrease SNR uncertainty: As an exaple, when the noralized aperture D/r 0 =10 is considered, increasing the nuber of subapertures L fro 1 to 19 decrease the ean SNR by roughly 6 db, fro 1dB to -5 db. As we observe in Fig. 4, the effects of scintillation are noticeable for the sall aperture diaeters and ust be properly considered. For relatively sall apertures, aplitude scintillation is doinant, and noralized variance is virtually unaffected by wavefront phase distortions. When the aperture is larger, phase distortion becoes doinant and the scintillation index σ β is of little relevance in the SNR uncertainty. Also, it results of interest to consider the case of independent subapertures. These independent signals could be obtained by spacing the ultiple subapertures in the array. If the output of a perfect L-eleents cobiner in the atosphere would be described as a su of L independently fading signals, the output SNR uncertainty would be apparently better. That is the case in the liit of weak turbulence or sall noralized apertures, where, for instances, when 7-eleents arrays are considered, the uncertainty is alost 4 db saller for ideal independent subapertures. This 4-dB difference is the penalty for using closely packed arrays that cobine highly correlated signals. However, when strong turbulence or large noralized apertures are considered, field coherence areas are saller than any array subaperture used in this analysis and the signals collected by then are ostly uncorrelated. In this regie, the ultiple replicas cobined at the array receiver are statistically independent and to distance the eleents of the array would not iprove the SNR uncertainty. Proc. of SPIE Vol Q-5 Downloaded fro SPIE Digital Library on Feb 011 to Ters of Use:

6 Figures 5 and 6 presents the SEP [10][11] for an L-eleents coherent fiber array receiver. Figure. 5 shows the perforance SEP vs. noralized aperture diaeter D/r 0, while Fig. 6 shows the perforance vs. turbulence-free SNR γ 0. In Fig. 5, for the sallest aperture diaeter considered, the turbulence-free SNR has a value γ 0 = 0 db. For any other aperture diaeter, the value of γ 0 is proportional to D.When we assue no scintillation, σ β =0, the effect of turbulence is siply to reduce the coherence length r 0. For a single large aperture, even using a relatively sall noralized aperture diaeter D/r 0 =1, turbulence introduces a strong perforance penalty at SEP. When ultiaperture array receivers are considered, in ost situations it yields a substantial perforance iproveent. An array with just L=19 subapertures yields significant iproveent for even the largest noralized apertures considered. The perforance of such array receiver is very close to the perforance expected in an AWGN syste. In Fig. 5, when large noralized apertures D/r 0 are considered, the SEP becoes independent of the scintillation index σ β, and tends toward an asyptotic value that is independent of noralized aperture diaeter D/r 0. Figure 6 shows the perforance for different values of L, the nuber of array eleents. Even using a relatively sall noralized aperture diaeter D/r 0 =, when a single large aperture receiver is used, turbulence introduces ore than a 30-dB perforance penalty at 10 3 SEP. When ultieleent arrays are used, perforance iproves arkedly. For instances, considering a sall array receiver with L=7 subapertures, at a SEP = 10-3 the SNR penalty is just below 10 db. This value should be contrasted with the 6-dB penalty observed in Fig. 6 when L=7 independently fading signals are ideally cobined. Also, although this results assue no scintillation, when we ipose a strong scintillation index of σ β =1 the penalty increase is less than 1 db at SEP = CONCLUSIONS We have nuerically evaluated the perforance of adaptive field conjugation array receivers in coherent laser counications through the turbulent atosphere. We analyze coherent fiber arrays consisting of densely packet ultiple subapertures in a hexagonal arrangeent and consider the effects of log-noral aplitude fluctuations and Gaussian phase fluctuations, in addition to local oscillator shot noise. By noting that the ipact of atospheric turbulence on coherent receivers can be statistically described by a Nakagai- probability density function, our odel uses fundaental principles of atospheric propagation and circuvents the need for a detailed description of the turbulence proble. For fiber adaptive arrays, where the atospheric fading on the subapertures is correlated or dependent, we can solve the proble by transforing it into an independent proble. A MGF-based approach used in our analysis has provided easily evaluable analytical expressions for the signal statistical oents and the sybol error probabilities. We have used it to study the effect of various paraeters on perforance, including turbulence level, signal strength, receive aperture size, and the nuber of subapertures in the coherent fiber array. We have separately quantified the effects of aplitude fluctuations and wavefront phase distortion on syste perforance, and have identified different regies of turbulence. For ost typical free-space laser counication situations, using coherent arrays with a reasonably sall nuber of subapertures such as L=19 increases the counication perforance by several decibels. The research of Aniceto Belonte was partially funded by the Spanish Departent of Science and Innovation MICINN Grant No. TEC REFERENCES [1] D. L. Fried, "Optical heterodyne detection of an atospherically distorted signal wave front," Proc. IEEE 55, (1967). [] R. M. Gagliardi and S. Karp, Optical Counications (John Wiley & Sons, 1995). [3] A. Belonte and J. M. Kahn, "Perforance of synchronous optical receivers using atospheric copensation techniques, Opt. Express 16, (008). [4] E. J. Lee and V. W. Chan, "Diversity Coherent and Incoherent Receivers for Free-Space Optical Counication in the Presence and Absence of Interference," J. Opt. Coun. Netw. 1, (009). [5] A. Belonte and J. M. Kahn, "Capacity of coherent free-space optical links using diversity-cobining techniques," Opt. Express 17, (009). Proc. of SPIE Vol Q-6 Downloaded fro SPIE Digital Library on Feb 011 to Ters of Use:

7 [6] M. Nakagai, The -distribution. A general forula of intensity distribution of rapid fading, in Statistical Methods in Radio Wave Propagation, W. C. Hoffan, ed. (Pergaon Press, 1960). [7] J. D. Parsons, Diversity techniques in counications receivers, in Advanced Signal Processing, D. A. Creasey, ed. (Peregrinus, 1985), Chap. 6. [8] P. J. Winzer and W. R. Leeb, Fiber coupling efficiency for rando light and its applications to lidar, Opt. Letters 3, (1998). [9] J. W. Strohbehn, T. Wang, and J. P. Speck, On the probability distribution of line-of-sight fluctuations of optical signals, Radio Science 10, (1975). [10] J. G. Proakis and M. Salehi, Digital Counications, (Mc Graw-Hill, 007). [11] M. K. Sion and M.-S. Alouini, A unified approach to the perforance analysis of digital counications over generalized fading channels, IEEE Proc. 86, (1998). Figure 1. A coherent free-space optical counication syste is affected by the presence of atospheric turbulence in any ways. Aplitude scintillation and phase distortion in the receiver plane act as intense sources of noise distorting the quality of the optical signal available for processing and add together to deteriorate the overall counication perforance of the optical systes. In a field conjugation fiber array, the interediate-frequency signals at the output of the single-ode fibers are adaptively co-phased, have their aplitude separately adjusted, and then sued to itigate signal fading associated with atospheric turbulence. Figure. Adaptive arrays could be considered to alleviate the deteriorating effects of atospheric turbulence. We consider L- eleent coherent fiber arrays and assue that the subapertures are arranged in a hexagonal close-packed array. Proc. of SPIE Vol Q-7 Downloaded fro SPIE Digital Library on Feb 011 to Ters of Use:

8 Figure 3. Noralized ean coherent SNR vs. the noralized receiver aperture diaeter D/r 0. Perforance is shown for different values of the nuber of of supapertures L in the closely packed hexagonal coherent array. The case L=1 corresponds to a onolitic aperture (black line). When a single aperture is considered, D describes the receiver aperture diaeter. For coparison of the receiver perforance between an L-eleent coherent array and a single large aperture, we force the hexagonal array to be packed within the liits of the single aperture diaeter D. The analysis conteplates the array fill factor and considers a coupling-geoetry paraeterτ for each subaperture lens equal to 1.1. Figure 4. SNR noralized standard deviation vs. the noralized receiver aperture diaeter D/r 0. Perforance is shown for different values of the nuber of of supapertures L in the closely packed hexagonal coherent array. The case L=1 corresponds to a onolitic aperture (black line). When a single aperture is considered, D describes the receiver aperture diaeter. For coparison of the receiver perforance between an L-eleent coherent array and a single large aperture, we force the hexagonal array to be packed within the liits of the single aperture diaeter D. The analysis conteplates the array fill factor and considers a coupling-geoetry paraeterτ for each subaperture lens equal to Aplitude fluctuations are neglected (solid line) by assuing σ β =0. When scintillation is considered (dashed line), the scintillation index is fixed at σ β =1. The red, dotted line corresponds to the uncertainty associated with L=7 independent-subapertures liit where fading correlation is neglected. Proc. of SPIE Vol Q-8 Downloaded fro SPIE Digital Library on Feb 011 to Ters of Use:

9 Figure 5. SEP vs. noralized receiver aperture diaeter D/r 0 for QPSK with coherent detection and AWGN. Perforance is shown for different values of the nuber of of supapertures L in the closedly packed hexagonal coherent array. The case L=1 corresponds to a onolitic aperture (black line). When a single aperture is considered, D describes the receiver aperture diaeter. For coparison of the receiver perforance between an L-eleent coherent array and a single large aperture, we force the hexagonal array to be packed within the liits of the single aperture diaeter D. The analysis conteplates the array fill factor and considers a coupling-geoetry paraeterτ for each subaperture lens equal to 1.1. The turbulence-free SNR per sybol γ 0 is proportional to the square of the aperture diaeter D. For the sallest aperture considered, we assue γ 0 = 0 db. In all cases, aplitude fluctuations are neglected (solid line) by assuing σ β =0. When scintillation is considered for L=7 (red, dashed line), the scintillation index is fixed at σ β =1. Also for L=7, the red, dotted line corresponds to the SEP associated with the independent-subapertures liit where fading correlation is neglected.the no-turbulence, AWGN case is indicated by black, dashed lines. The best perforance shown inthis plots (dot black line) considers the AWGN liit withτ = 0 to obtain a unifor illuinated pupil. When copared with the τ = 1.1 case, the ean SNR is now 5-dB higher. Figure 6. SEP vs. nuber of photons per sybol for QPSK with coherent detection and AWGN. Perforance is shown for different values of the nuber of of supapertures L in the closedly packed hexagonal coherent array. The noralized aperture diaeter D/r 0 is set to. Other paraeters are siilar to those in Fig. 5. Once again, aplitude fluctuations are neglected (solid line) by assuing σ β =0. When scintillation is considered for L=7 (red, dashed line), the scintillation index is fixed at σ β =1. Also for L=7, the red, dotted line corresponds to the SEP associated with the independent-subapertures liit where fading correlation is neglected. Proc. of SPIE Vol Q-9 Downloaded fro SPIE Digital Library on Feb 011 to Ters of Use:

Understanding the performance of atmospheric free-space laser communications systems using coherent detection

Understanding the performance of atmospheric free-space laser communications systems using coherent detection !"#$%&'()*+&, Understanding the performance of atmospheric free-space laser communications systems using coherent detection Aniceto Belmonte Technical University of Catalonia, Department of Signal Theory

More information

Efficiency of complex modulation methods in coherent free-space optical links

Efficiency of complex modulation methods in coherent free-space optical links Efficiency of complex modulation methods in coherent free-space optical links Aniceto Belmonte 1,* and Joseph M. Kahn 1 Technical University of Catalonia, Department of Signal Theory and Communications,

More information

A New Simple Model for Land Mobile Satellite Channels

A New Simple Model for Land Mobile Satellite Channels A New Siple Model for Land Mobile Satellite Channels A. Abdi, W. C. Lau, M.-S. Alouini, and M. Kaveh Dept. of Elec. and Cop. Eng., University of Minnesota, Minneapolis, MN 55455 Eails: {abdi, wlau, alouini,

More information

Relation between C/N Ratio and S/N Ratio

Relation between C/N Ratio and S/N Ratio Relation between C/N Ratio and S/N Ratio In our discussion in the past few lectures, we have coputed the C/N ratio of the received signals at different points of the satellite transission syste. The C/N

More information

Using Adaptive Modulation in a LEO Satellite Communication System

Using Adaptive Modulation in a LEO Satellite Communication System Proceedings of the 11th WSEAS International Conference on COMMUNICATIONS, Agios Nikolaos, Crete Island, Greece, July 26-28, 27 255 Using Adaptive Modulation in a LEO Satellite Counication Syste L. HADJ

More information

Notes on Orthogonal Frequency Division Multiplexing (OFDM)

Notes on Orthogonal Frequency Division Multiplexing (OFDM) Notes on Orthogonal Frequency Division Multiplexing (OFDM). Discrete Fourier ransfor As a reinder, the analytic fors of Fourier and inverse Fourier transfors are X f x t t, f dt x t exp j2 ft dt (.) where

More information

Sequential Optimization of Adaptive Arrays in Coherent Laser Communications

Sequential Optimization of Adaptive Arrays in Coherent Laser Communications JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 31, NO. 9, MAY 1, 2013 1383 Sequential Optimization of Adaptive Arrays in Coherent Laser Communications Aniceto Belmonte and Joseph M. Kahn Abstract In optical wireless

More information

Adaptive Harmonic IIR Notch Filter with Varying Notch Bandwidth and Convergence Factor

Adaptive Harmonic IIR Notch Filter with Varying Notch Bandwidth and Convergence Factor Journal of Counication and Coputer (4 484-49 doi:.765/548-779/4.6. D DAVID PUBLISHING Adaptive Haronic IIR Notch Filter with Varying Notch Bandwidth and Convergence Factor Li Tan, Jean Jiang, and Liango

More information

DSI3 Sensor to Master Current Threshold Adaptation for Pattern Recognition

DSI3 Sensor to Master Current Threshold Adaptation for Pattern Recognition International Journal of Signal Processing Systes Vol., No. Deceber 03 DSI3 Sensor to Master Current Threshold Adaptation for Pattern Recognition David Levy Infineon Austria AG, Autootive Power Train Systes,

More information

RAKE Receiver. Tommi Heikkilä S Postgraduate Course in Radio Communications, Autumn II.

RAKE Receiver. Tommi Heikkilä S Postgraduate Course in Radio Communications, Autumn II. S-72333 Postgraduate Course in Radio Counications, Autun 2004 1 RAKE Receiver Toi Heikkilä toiheikkila@teliasoneraco Abstract RAKE receiver is used in CDMA-based (Code Division Multiple Access) systes

More information

Modeling Beam forming in Circular Antenna Array with Directional Emitters

Modeling Beam forming in Circular Antenna Array with Directional Emitters International Journal of Research in Engineering and Science (IJRES) ISSN (Online): 2320-9364, ISSN (Print): 2320-9356 Volue 5 Issue 3 ǁ Mar. 2017 ǁ PP.01-05 Modeling Bea foring in Circular Antenna Array

More information

ELEC2202 Communications Engineering Laboratory Frequency Modulation (FM)

ELEC2202 Communications Engineering Laboratory Frequency Modulation (FM) ELEC Counications Engineering Laboratory ---- Frequency Modulation (FM) 1. Objectives On copletion of this laboratory you will be failiar with: Frequency odulators (FM), Modulation index, Bandwidth, FM

More information

An orthogonal multi-beam based MIMO scheme. for multi-user wireless systems

An orthogonal multi-beam based MIMO scheme. for multi-user wireless systems An orthogonal ulti-bea based IO schee for ulti-user wireless systes Dong-chan Oh o and Yong-Hwan Lee School of Electrical Engineering and IC, Seoul ational University Kwana P.O. Box 34, Seoul, 151-600,

More information

Keywords Frequency-domain equalization, antenna diversity, multicode DS-CDMA, frequency-selective fading

Keywords Frequency-domain equalization, antenna diversity, multicode DS-CDMA, frequency-selective fading Joint Frequency-doain Equalization and Antenna Diversity Cobining for Orthogonal Multicode DS-CDMA Signal Transissions in A Frequency-selective Fading Channel Taeshi ITAGAKI *1 and Fuiyui ADACHI *2 Dept.

More information

Characterization and Modeling of Underwater Acoustic Communications Channels for Frequency-Shift-Keying Signals

Characterization and Modeling of Underwater Acoustic Communications Channels for Frequency-Shift-Keying Signals Characterization and Modeling of Underwater Acoustic Counications Channels for Frequency-Shift-Keying Signals Wen-Bin Yang and T.C. Yang Naval Research Laboratory Washington, DC 375 USA Abstract In a fading

More information

Allocation of Multiple Services in Multi-Access Wireless Systems

Allocation of Multiple Services in Multi-Access Wireless Systems Allocation of Multiple Serices in Multi-Access Wireless Systes Anders Furuskär Wireless@KTH, Royal Institute of Technology, Sweden and Ericsson Research anders.furuskar@era.ericsson.se Abstract This paper

More information

REPORT ITU-R SA Telecommunication characteristics and requirements for space VLBI systems

REPORT ITU-R SA Telecommunication characteristics and requirements for space VLBI systems Rep. ITU-R SA.2132 1 REPORT ITU-R SA.2132 Telecounication characteristics and requireents for space VLBI systes (2008) This Report describes the characteristics of the space VLBI systes. These characteristics

More information

Outage Probability of Alamouti based Cooperative Communications with Multiple Relay Nodes using Network Coding

Outage Probability of Alamouti based Cooperative Communications with Multiple Relay Nodes using Network Coding Outage Probability of Alaouti based Cooperative Counications with Multiple Relay Nodes using Network Coding Gordhan Das Menghwar and Christoph F. Mecklenbräuker 2 Inforation Technology Centre Sindh Agriculture

More information

Intermediate-Node Initiated Reservation (IIR): A New Signaling Scheme for Wavelength-Routed Networks with Sparse Conversion

Intermediate-Node Initiated Reservation (IIR): A New Signaling Scheme for Wavelength-Routed Networks with Sparse Conversion Interediate-Node Initiated Reservation IIR): A New Signaling Schee for Wavelength-Routed Networks with Sparse Conversion Kejie Lu, Jason P. Jue, Tiucin Ozugur, Gaoxi Xiao, and Irich Chlatac The Center

More information

SECURITY AND BER PERFORMANCE TRADE-OFF IN WIRELESS COMMUNICATION SYSTEMS APPLICATIONS

SECURITY AND BER PERFORMANCE TRADE-OFF IN WIRELESS COMMUNICATION SYSTEMS APPLICATIONS Latin Aerican Applied Research 39:187-192 (2009) SECURITY AND BER PERFORMANCE TRADE-OFF IN WIRELESS COMMUNICATION SYSTEMS APPLICATIONS L. ARNONE, C. GONZÁLEZ, C. GAYOSO, J. CASTIÑEIRA MOREIRA and M. LIBERATORI

More information

Simplified Analysis and Design of MIMO Ad Hoc Networks

Simplified Analysis and Design of MIMO Ad Hoc Networks Siplified Analysis and Design of MIMO Ad Hoc Networks Sunil Srinivasa and Martin Haenggi Departent of Electrical Engineering University of Notre Dae Notre Dae, IN 46556, USA Eail: {ssriniv, haenggi}@nd.edu

More information

Fundamental study for measuring microflow with Michelson interferometer enhanced by external random signal

Fundamental study for measuring microflow with Michelson interferometer enhanced by external random signal Bulletin of the JSME Journal of Advanced Mechanical Design, Systes, and Manufacturing Vol.8, No.4, 2014 Fundaental study for easuring icroflow with Michelson interferoeter enhanced by external rando signal

More information

COMBINED FREQUENCY AND SPATIAL DOMAINS POWER DISTRIBUTION FOR MIMO-OFDM TRANSMISSION

COMBINED FREQUENCY AND SPATIAL DOMAINS POWER DISTRIBUTION FOR MIMO-OFDM TRANSMISSION The 8th nnual IEEE International Syposiu on Personal, Indoor and Mobile Radio Counications (PIMRC 07) COMINED FREQUENCY ND SPTIL DOMINS POWER DISTRIUTION FOR MIMO-OFDM TRNSMISSION Wladiir ocquet, Kazunori

More information

Power Optimal Signaling for Fading Multi-access Channel in Presence of Coding Gap

Power Optimal Signaling for Fading Multi-access Channel in Presence of Coding Gap Power Optial Signaling for Fading Multi-access Channel in Presence of Coding Gap Ankit Sethi, Prasanna Chaporkar, and Abhay Karandikar Abstract In a ulti-access fading channel, dynaic allocation of bandwidth,

More information

PREDICTING SOUND LEVELS BEHIND BUILDINGS - HOW MANY REFLECTIONS SHOULD I USE? Apex Acoustics Ltd, Gateshead, UK

PREDICTING SOUND LEVELS BEHIND BUILDINGS - HOW MANY REFLECTIONS SHOULD I USE? Apex Acoustics Ltd, Gateshead, UK PREDICTING SOUND LEVELS BEHIND BUILDINGS - HOW MANY REFLECTIONS SHOULD I USE? W Wei A Cooke J Havie-Clark Apex Acoustics Ltd, Gateshead, UK Apex Acoustics Ltd, Gateshead, UK Apex Acoustics Ltd, Gateshead,

More information

A Novel NLOS Mitigation Approach for Wireless Positioning System

A Novel NLOS Mitigation Approach for Wireless Positioning System 2 3rd International Conference on Coputer and Electrical Engineering (ICCEE 2) IPCSIT vol. 53 (22) (22) IACSIT Press, Singapore DOI:.7763/IPCSIT.22.V53.No..54 A Novel NLOS Mitigation Approach for Wireless

More information

Enhanced Algorithm for MIESM

Enhanced Algorithm for MIESM Recent Patents on Signal Processing, 9,, -7 Enhanced Algorith for MIESM R. Sandanalakshi *, Shahid Mutaz * and Kazi Saidul * Open Access University of Aveiro, Aveiro, Portugal Abstract: The link adaptation

More information

Spectrum Sensing in Low SNR: Diversity Combining and Cooperative Communications

Spectrum Sensing in Low SNR: Diversity Combining and Cooperative Communications 0 6th International Conference on Industrial and Inforation Systes, ICIIS 0, Aug. 6-9, 0, Sri Lanka Spectru Sensing in Low SR: Diversity Cobining and Cooperative Counications Saan Atapattu, Chintha Tellabura,

More information

Design of an Arrayed Waveguide Grating with flat spectral response

Design of an Arrayed Waveguide Grating with flat spectral response Design of an Arrayed Waveguide Grating with flat spectral response Thoas Kaalakis, Thoas Sphicopoulos and Diitris Syvridis (Departent of Inforatics and Telecounications, University of Athens, Panepistiiopolis,

More information

COMPARISON OF TOKEN HOLDING TIME STRATEGIES FOR A STATIC TOKEN PASSING BUS. M.E. Ulug

COMPARISON OF TOKEN HOLDING TIME STRATEGIES FOR A STATIC TOKEN PASSING BUS. M.E. Ulug COMPARISON OF TOKEN HOLDING TIME STRATEGIES FOR A STATIC TOKEN PASSING BUS M.E. Ulug General Electric Corporate Research and Developent Schenectady, New York 1245 ABSTRACT Waiting ties have been calculated

More information

Kalman Filtering for NLOS Mitigation and Target Tracking in Indoor Wireless Environment

Kalman Filtering for NLOS Mitigation and Target Tracking in Indoor Wireless Environment 16 Kalan Filtering for NLOS Mitigation and Target Tracking in Indoor Wireless Environent Chin-Der Wann National Sun Yat-Sen University Taiwan 1. Introduction Kalan filter and its nonlinear extension, extended

More information

A soft decision decoding of product BCH and Reed-Müller codes for error control and peak-factor reduction in OFDM

A soft decision decoding of product BCH and Reed-Müller codes for error control and peak-factor reduction in OFDM A soft decision decoding of product BCH and Reed-Müller codes for error control and pea-factor reduction in OFDM Yves LOUET *, Annic LE GLAUNEC ** and Pierre LERAY ** * PhD Student and ** Professors, Departent

More information

] (1) Problem 1. University of California, Berkeley Fall 2010 EE142, Problem Set #9 Solutions Prof. Jan Rabaey

] (1) Problem 1. University of California, Berkeley Fall 2010 EE142, Problem Set #9 Solutions Prof. Jan Rabaey University of California, Berkeley Fall 00 EE4, Proble Set #9 Solutions Ain Arbabian Prof. Jan Rabaey Proble Since the ixer is a down-conversion type with low side injection f LO 700 MHz and f RF f IF

More information

LETTER Adaptive Multi-Stage Parallel Interference Cancellation Receiver for Multi-Rate DS-CDMA System

LETTER Adaptive Multi-Stage Parallel Interference Cancellation Receiver for Multi-Rate DS-CDMA System IEICE TRANS. COMMUN., VOL.E87 B, NO.8 AUGUST 2004 2401 LETTER Adaptive Multi-Stage Parallel Interference Cancellation Receiver for Multi-Rate DS-CDMA Syste Seung Hee HAN a), Student Meber and Jae Hong

More information

Transmit Power and Bit Allocations for OFDM Systems in a Fading Channel

Transmit Power and Bit Allocations for OFDM Systems in a Fading Channel Transit Power and Bit Allocations for OFD Systes in a Fading Channel Jiho Jang *, Kwang Bok Lee, and Yong-Hwan Lee * Sasung Electronics Co. Ltd., Suwon P.O.Box, Suwon-si, Gyeonggi-do 44-74, Korea School

More information

Investigating Multiple Alternating Cooperative Broadcasts to Enhance Network Longevity

Investigating Multiple Alternating Cooperative Broadcasts to Enhance Network Longevity Investigating Multiple Alternating Cooperative Broadcasts to Enhance Network Longevity Aravind Kailas School of Electrical and Coputer Engineering Georgia Institute of Technology Atlanta, Georgia 3033-050,

More information

Iterative Receiver Signal Processing for Joint Mitigation of Transmitter and Receiver Phase Noise in OFDM-Based Cognitive Radio Link

Iterative Receiver Signal Processing for Joint Mitigation of Transmitter and Receiver Phase Noise in OFDM-Based Cognitive Radio Link Iterative Receiver Signal Processing for Joint Mitigation of Transitter and Receiver Phase Noise in OFDM-Based Cognitive Radio Link Ville Syrjälä and Mikko Valkaa Departent of Counications Engineering

More information

Success Probability of Millimeter-Wave D2D Networks with Heterogeneous Antenna Arrays

Success Probability of Millimeter-Wave D2D Networks with Heterogeneous Antenna Arrays Success Probability of Millieter-Wave D2D Networks with Heterogeneous Antenna Arrays Na Deng, Yi Sun School of Inforation & Counication Engineering Dalian University of Technology Dalian, Liaoning, 11624,

More information

PARAMETER OPTIMIZATION OF THE ADAPTIVE MVDR QR-BASED BEAMFORMER FOR JAMMING AND MULTIPATH SUPRESSION IN GPS/GLONASS RECEIVERS

PARAMETER OPTIMIZATION OF THE ADAPTIVE MVDR QR-BASED BEAMFORMER FOR JAMMING AND MULTIPATH SUPRESSION IN GPS/GLONASS RECEIVERS PARAMETER OPTIMIZATION OF THE ADAPTIVE MVDR QR-BASED BEAMFORMER FOR JAMMING AND MULTIPATH SUPRESSION IN GPS/GLONASS RECEIVERS V. Behar 1, Ch. Kabakchiev 2, G. Gaydadjiev 3, G.Kuzanov 4, P. Ganchosov 5

More information

Compensated Single-Phase Rectifier

Compensated Single-Phase Rectifier Copensated Single-Phase Rectifier Jānis DoniĦš Riga Technical university jdonins@gail.co Abstract- Paper describes ethods of rectified DC pulsation reduction adding a ensation node to a single phase rectifier.

More information

Introduction Traditionally, studying outage or cellular systes has been based on the signal-to-intererence ratio (SIR) dropping below a required thres

Introduction Traditionally, studying outage or cellular systes has been based on the signal-to-intererence ratio (SIR) dropping below a required thres Miniu Duration Outages in Rayleigh Fading Channels Jie Lai and Narayan B. Mandaya WINLAB, Rutgers University 73 Brett Rd., Piscataway, NJ 8854-86 Eail: jlai@winlab.rutgers.edu, narayan@winlab.rutgers.edu

More information

Overlapping Signal Separation in DPX Spectrum Based on EM Algorithm. Chuandang Liu 1, a, Luxi Lu 1, b

Overlapping Signal Separation in DPX Spectrum Based on EM Algorithm. Chuandang Liu 1, a, Luxi Lu 1, b nd International Worshop on Materials Engineering and Coputer Sciences (IWMECS 015) Overlapping Signal Separation in DPX Spectru Based on EM Algorith Chuandang Liu 1, a, Luxi Lu 1, b 1 National Key Laboratory

More information

OTC Statistics of High- and Low-Frequency Motions of a Moored Tanker. sensitive to lateral loading such as the SAL5 and

OTC Statistics of High- and Low-Frequency Motions of a Moored Tanker. sensitive to lateral loading such as the SAL5 and OTC 61 78 Statistics of High- and Low-Frequency Motions of a Moored Tanker by J.A..Pinkster, Maritie Research Inst. Netherlands Copyright 1989, Offshore Technology Conference This paper was presented at

More information

Optimal Modulation Index of the Mach-Zehnder Modulator in a Coherent Optical OFDM System Employing Digital Predistortion

Optimal Modulation Index of the Mach-Zehnder Modulator in a Coherent Optical OFDM System Employing Digital Predistortion Optial Modulation Index of the Mach-Zehnder Modulator in a Coherent Optical OFDM yste Eploying Digital redistortion David Rörich, Xiaojie Wang, Michael Bernhard, Joachi peidel Universität tuttgart, Institut

More information

Ignition and monitoring technique for plasma processing of multicell superconducting radio frequency cavities

Ignition and monitoring technique for plasma processing of multicell superconducting radio frequency cavities Ignition and onitoring technique for plasa processing of ulticell superconducting radio frequency cavities Marc Doleans Oak Ridge ational Laboratory, Oak Ridge, Tennessee 3783, USA E ail: doleans@ornl.gov

More information

Indoor Multiple-Antenna Channel Characterization from 2 to 8 GHz

Indoor Multiple-Antenna Channel Characterization from 2 to 8 GHz Indoor Multiple-Antenna Channel Characterization fro to 8 GHz Ada S Y Poon and Minnie Ho Counications and Interconnect Lab, Intel Corporation Abstract In ultiple-antenna channels, e optiality of a transission

More information

Cooperative Hybrid-ARQ Protocols: Unified Frameworks for Protocol Analysis

Cooperative Hybrid-ARQ Protocols: Unified Frameworks for Protocol Analysis Cooperative Hybrid-ARQ Protocols: Unified Fraeworks for Protocol Analysis Ilu Byun and Kwang Soon Ki Cooperative hybrid-autoatic repeat request (HARQ) protocols, which can exploit the spatial and teporal

More information

Optical fiber beamformer for processing two independent simultaneous RF beams

Optical fiber beamformer for processing two independent simultaneous RF beams Optical fiber beaforer for processing two independent siultaneous RF beas M. Jaeger, S. Granieri *, and A. Siahakoun Departent of Physics and Optical Engineering, Rose-Hulan Institute of Technology Terre

More information

Experiment 7: Frequency Modulation and Phase Locked Loops October 11, 2006

Experiment 7: Frequency Modulation and Phase Locked Loops October 11, 2006 Experient 7: Frequency Modulation and Phase ocked oops October 11, 2006 Frequency Modulation Norally, we consider a voltage wave for with a fixed frequency of the for v(t) = V sin(ω c t + θ), (1) where

More information

EXPERIMENTAL VERIFICATION OF SINUSOIDAL APPROXIMATION IN ANALYSIS OF THREE-PHASE TWELVE-PULSE OUTPUT VOLTAGE TYPE RECTIFIERS

EXPERIMENTAL VERIFICATION OF SINUSOIDAL APPROXIMATION IN ANALYSIS OF THREE-PHASE TWELVE-PULSE OUTPUT VOLTAGE TYPE RECTIFIERS th INTERNATIONAL SYPOSIU on POWER ELECTRONICS - Ee 9 XV eđunarodni sipoziju Energetska elektronika Ee 9 NOVI SAD, REPUBLIC OF SERBIA, October 8 th - th, 9 EXPERIENTAL VERIFICATION OF SINUSOIDAL APPROXIATION

More information

A Novel Frequency Independent Simultaneous Matching Technique for Power Gain and Linearity in BJT amplifiers

A Novel Frequency Independent Simultaneous Matching Technique for Power Gain and Linearity in BJT amplifiers A Novel requency Independent iultaneous Matching Technique for Power Gain and Linearity in BJT aplifiers Mark P. van der Heijden, Henk. de Graaff, Leo. N. de Vreede Laboratory of Electronic oponents, Technology

More information

Chapter 10 Threaded Fasteners and Power Screws

Chapter 10 Threaded Fasteners and Power Screws Chapter 10 Threaded Fasteners and Power Screws 10.1 Introduction A layan ight consider threaded fasteners (screws, nuts, and bolts) to be the ost undane and uninteresting of all achine eleents. In fact

More information

POWER QUALITY ASSESSMENT USING TWO STAGE NONLINEAR ESTIMATION NUMERICAL ALGORITHM

POWER QUALITY ASSESSMENT USING TWO STAGE NONLINEAR ESTIMATION NUMERICAL ALGORITHM POWER QUALITY ASSESSENT USING TWO STAGE NONLINEAR ESTIATION NUERICAL ALGORITH Vladiir Terzia ABB Gerany vadiir.terzia@de.abb.co Vladiir Stanoevic EPS Yugoslavia vla_sta@hotail.co artin axiini ABB Gerany

More information

Multicarrier Interleave-Division Multiple Access Communication in Multipath Channels

Multicarrier Interleave-Division Multiple Access Communication in Multipath Channels Multicarrier Interleave-Division Multiple Access Counication in Multipath Channels Habib ur Rehan *, Muhaad Naee **, Iran Zaa *, Syed Isail Shah ** * Center for Advanced Studies in Engineering (CASE) Islaabad

More information

Fiber Bragg grating based four-bit optical beamformer

Fiber Bragg grating based four-bit optical beamformer Fiber Bragg grating based four-bit optical beaforer Sean Durrant a, Sergio Granieri a, Azad Siahakoun a, Bruce Black b a Departent of Physics and Optical Engineering b Departent of Electrical and Coputer

More information

Phase Noise Modelling and Mitigation Techniques in OFDM Communications Systems

Phase Noise Modelling and Mitigation Techniques in OFDM Communications Systems Phase Noise Modelling and Mitigation Techniques in OFDM Counications Systes Ville Syrjälä, Mikko Valkaa, Nikolay N. Tchaov, and Jukka Rinne Tapere University of Technology Departent of Counications Engineering

More information

2-Dimensional beamsteering using dispersive deflectors and wavelength tuning

2-Dimensional beamsteering using dispersive deflectors and wavelength tuning 2-Diensional beasteering using dispersive deflectors and wavelength tuning Trevor Chan, 1,* Evgeny Myslivets, 1 and Joseph E. Ford, 1 1 Departent of Electrical and Coputer Engineering, University of California,

More information

Study and Implementation of Complementary Golay Sequences for PAR reduction in OFDM signals

Study and Implementation of Complementary Golay Sequences for PAR reduction in OFDM signals Study and Ipleentation of Copleentary Golay Sequences for PAR reduction in OFDM signals Abstract In this paper soe results of PAR reduction in OFDM signals and error correction capabilities by using Copleentary

More information

Performance Evaluation of UWB Sensor Network with Aloha Multiple Access Scheme

Performance Evaluation of UWB Sensor Network with Aloha Multiple Access Scheme 1 Perforance Evaluation of UWB Sensor Network with Aloha Multiple Access Schee Roeo Giuliano 1 and Franco Mazzenga 2 1 RadioLabs Consorzio Università Industria, Via del Politecnico 1, 00133, Roe, Italy,

More information

New Adaptive Linear Combination Structure for Tracking/Estimating Phasor and Frequency of Power System

New Adaptive Linear Combination Structure for Tracking/Estimating Phasor and Frequency of Power System 28 Journal of Electrical Engineering & echnology Vol. 5, No., pp. 28~35, 2 New Adaptive Linear Cobination Structure for racking/estiating Phasor and Frequency of Power Syste Choowong-Wattanasakpubal and

More information

Power-Efficient Resource Allocation for MC-NOMA with Statistical Channel State Information

Power-Efficient Resource Allocation for MC-NOMA with Statistical Channel State Information Power-Efficient Resource Allocation for MC-NOMA with Statistical Channel State Inforation Zhiqiang Wei, Derrick Wing Kwan Ng, and Jinhong Yuan School of Electrical Engineering and Telecounications, The

More information

NINTH INTERNATIONAL CONGRESS ON SOUND AND VIBRATION, ICSV9 PASSIVE CONTROL OF LAUNCH NOISE IN ROCKET PAYLOAD BAYS

NINTH INTERNATIONAL CONGRESS ON SOUND AND VIBRATION, ICSV9 PASSIVE CONTROL OF LAUNCH NOISE IN ROCKET PAYLOAD BAYS first nae & faily nae: Rick Morgans Page nuber: 1 NINTH INTERNATIONAL CONGRESS ON SOUND AND VIBRATION, ICSV9 PASSIVE CONTROL OF LAUNCH NOISE IN ROCKET PAYLOAD BAYS Rick Morgans, Ben Cazzolato, Anthony

More information

EFFECTS OF MASKING ANGLE AND MULTIPATH ON GALILEO PERFORMANCES IN DIFFERENT ENVIRONMENTS

EFFECTS OF MASKING ANGLE AND MULTIPATH ON GALILEO PERFORMANCES IN DIFFERENT ENVIRONMENTS 1 EFFECTS OF MASKING ANGLE AND MULTIPATH ON GALILEO PERFORMANCES IN DIFFERENT ENVIRONMENTS M. Malicorne*, M. Bousquet**, V. Calettes*** SUPAERO, 1 avenue Edouard Belin BP 43, 3155 Toulouse Cedex, France.

More information

WIPL-D Pro: What is New in v12.0?

WIPL-D Pro: What is New in v12.0? WIPL-D Pro: What is New in v12.0? Iproveents/new features introduced in v12.0 are: 1. Extended - Extree Liits a. Extreely LOW contrast aterials b. Extended resolution for radiation pattern c. Extreely

More information

Boris Krnic Nov 15, ECE 1352F. Phase Noise of VCOs

Boris Krnic Nov 15, ECE 1352F. Phase Noise of VCOs Boris Krnic Nov 15, 93 187 13 ECE 135F Phase Noise of VCOs. ABSTRACT The ain purpose of this paper is to present siplified first order noise analysis techniques as applied to ring VCOs. The scarcity of

More information

Transmit Beamforming and Iterative Water-Filling Based on SLNR for OFDMA Systems

Transmit Beamforming and Iterative Water-Filling Based on SLNR for OFDMA Systems Transit Beaforing and Iterative Water-Filling Based on SLNR for OFDMA Systes Kazunori Hayashi, Megui Kaneko, Takeshi Fui, Hideaki Sakai Graduate School of Inforatics, Kyoto University, Yoshida Honachi

More information

Mitigation of GPS L 2 signal in the H I observation based on NLMS algorithm Zhong Danmei 1, a, Wang zhan 1, a, Cheng zhu 1, a, Huang Da 1, a

Mitigation of GPS L 2 signal in the H I observation based on NLMS algorithm Zhong Danmei 1, a, Wang zhan 1, a, Cheng zhu 1, a, Huang Da 1, a 2nd International Conference on Electrical, Coputer Engineering and Electronics (ICECEE 25 Mitigation of GPS L 2 signal in the H I observation based on NLMS algorith Zhong Danei, a, Wang zhan, a, Cheng

More information

A Novel TDS-FDMA Scheme for Multi-User Uplink Scenarios

A Novel TDS-FDMA Scheme for Multi-User Uplink Scenarios A Novel TDS-FDMA Schee for Multi-User Uplink Scenarios Linglong Dai, Zhaocheng Wang, Jun Wang, and Zhixing Yang Tsinghua National Laboratory for Inforation Science and Technology, Electronics Engineering

More information

Radio Resource Management in a Coordinated Cellular Distributed Antenna System By Using Particle Swarm Optimization

Radio Resource Management in a Coordinated Cellular Distributed Antenna System By Using Particle Swarm Optimization Radio Resource Manageent in a Coordinated Cellular Distributed Antenna Syste By Using Particle Swar Optiization Oer Haliloglu (1), Cenk Toker (1), Gurhan Bulu (1), Hali Yanikoeroglu (2) (1) Departent of

More information

On the Impact of Exponent Multipath and Branch Correlation on MC-CDMA System in Frequency-Selective Fading Environments

On the Impact of Exponent Multipath and Branch Correlation on MC-CDMA System in Frequency-Selective Fading Environments IAENG International Journal of Coputer Science, 33:, IJCS_33 5 On the Ipact of Exponent Multipath and Branch Correlation on MC-CDMA Syste in Frequency-Selective Fading Environents Joy Iong-Zong Chen, Chieh

More information

A Frequency Domain Approach to Design Constrained Amplitude Spreading Sequences for DS-CDMA Systems for Frequency Selective Fading Channels

A Frequency Domain Approach to Design Constrained Amplitude Spreading Sequences for DS-CDMA Systems for Frequency Selective Fading Channels A Frequency Doain Approach to Design Constrained Aplitude Spreading Sequences for DS-CDMA Systes for Frequency Selective Fading Channels B.J.Peiris, K.R.Narayanan and S.L. Miller Dept. of Electrical Engineering

More information

NONLINEAR WAVELET PACKET DENOISING OF IMPULSIVE VIBRATION SIGNALS NIKOLAOS G. NIKOLAOU, IOANNIS A. ANTONIADIS

NONLINEAR WAVELET PACKET DENOISING OF IMPULSIVE VIBRATION SIGNALS NIKOLAOS G. NIKOLAOU, IOANNIS A. ANTONIADIS NONLINEAR WAVELET PACKET DENOISING OF IMPULSIVE VIBRATION SIGNALS NIKOLAOS G. NIKOLAOU, IOANNIS A. ANTONIADIS Departent of Mechanical Engineering, Machine Design and Control Systes Section National Technical

More information

A Selection Region Based Routing Protocol for Random Mobile ad hoc Networks with Directional Antennas

A Selection Region Based Routing Protocol for Random Mobile ad hoc Networks with Directional Antennas A Selection Region Based Routing Protocol for Rando Mobile ad hoc Networks with Directional Antennas arxiv:1011.6017v1 cs.it] 8 Nov 010 Di Li, Changchuan Yin, and Changhai Chen Key Laboratory of Universal

More information

Wavelength-Selective Switches for Mode-Division Multiplexing: Scaling and Performance Analysis

Wavelength-Selective Switches for Mode-Division Multiplexing: Scaling and Performance Analysis JLT-64-4: K.-P. Ho et al, Wavelength-Selective Switches for Mode-Division Multiplexing Wavelength-Selective Switches for Mode-Division Multiplexing: Scaling and Perforance Analysis Keang-Po Ho, Senior

More information

A simple charge sensitive preamplifier for experiments with a small number of detector channels

A simple charge sensitive preamplifier for experiments with a small number of detector channels A siple charge sensitive preaplifier for experients with a sall nuber of detector channels laudio Arnaboldi and Gianluigi Pessina Istituto Nazionale di Fisica Nucleare (INFN) Università degli Studi di

More information

LOW COST PRODUCTION PHASE NOISE MEASUREMENTS ON MICROWAVE AND MILLIMETRE WAVE FREQUENCY SOURCES

LOW COST PRODUCTION PHASE NOISE MEASUREMENTS ON MICROWAVE AND MILLIMETRE WAVE FREQUENCY SOURCES Page 1 of 10 LOW COST PRODUCTION PHASE NOISE MEASUREMENTS ON MICROWAVE AND MILLIMETRE WAVE FREQUENCY SOURCES Hugh McPherson Spectral Line Systes Ltd, Units 1,2&3 Scott Road, Tarbert, Isle of Harris. www.spectral-line-systes.co.uk

More information

HIGH FREQUENCY LASER BASED ACOUSTIC MICROSCOPY USING A CW GENERATION SOURCE

HIGH FREQUENCY LASER BASED ACOUSTIC MICROSCOPY USING A CW GENERATION SOURCE HIGH FREQUENCY LASER BASED ACOUSTIC MICROSCOPY USING A CW GENERATION SOURCE T.W. Murray, O. Balogun, and N. Pratt Departent of Aerospace and Mechanical Engineering, Boston University, Boston MA 0225 Abstract:

More information

2. COMBAT EXPERIMENTAL SETTINGS

2. COMBAT EXPERIMENTAL SETTINGS Coparison of turbulence-induced scintillations for ulti-wavelength laser beacons over tactical (7 k) and long (149 k) atospheric propagation paths M. Vorontsov 1, V. S. Rao Gudietla, G. Carhart 3, T. Weyrauch

More information

SIG: Signal-Processing

SIG: Signal-Processing TH Köln - Technology, Arts, Sciences Prof. Dr. Rainer Bartz SIG: Signal-Processing Copendiu (6) Prof. Dr.-Ing. Rainer Bartz rainer.bartz@th-koeln.de Contact: eail: website: office: rainer.bartz@th-koeln.de

More information

Travel-Time and Amplitude Sensitivity Kernels

Travel-Time and Amplitude Sensitivity Kernels DISTRIBUTION STATEMENT A. Approved for public release; distribution is unliited. Travel-Tie and Aplitude Sensitivity Kernels Eanuel Skarsoulis Foundation for Research and Technology Hellas Institute of

More information

Energy-Efficient Cellular Communications Powered by Smart Grid Technology

Energy-Efficient Cellular Communications Powered by Smart Grid Technology Energy-Efficient Cellular Counications Powered by Sart Grid Technology Itiaz Nasi, Mostafa Zaan Chowdhury, and Md. Syadus Sefat Departent of Electrical and Electronic Engineering Khulna University of Engineering

More information

Receive Antenna Subset Selection For Time-Varying Channels Using Slepian Subspace Projections

Receive Antenna Subset Selection For Time-Varying Channels Using Slepian Subspace Projections Globeco - Wireless Counications Syposiu Receive Antenna Subset Selection For Tie-Varying Channels Using Slepian Subspace Projections Hassan A Abou Saleh and Steven D Blostein Departent of Electrical and

More information

Published in: ICWMC 2015, The Eleventh International Conference on Wireless and Mobile Communications

Published in: ICWMC 2015, The Eleventh International Conference on Wireless and Mobile Communications Aalborg Universitet Throughput Analysis of Full Duplex Counication with Asyetric Traffic in Sall Cell Systes Mahood, Nurul Huda; Berardinelli, Gilberto; Mogensen, Preben Elgaard; Frederiksen, Frank Published

More information

Lab 5: Differential Amplifier.

Lab 5: Differential Amplifier. epartent of Electrical and oputer Engineering Fall 1 Lab 5: ifferential plifier. 1. OBJETIVES Explore the operation of differential FET aplifier with resistive and active loads: Measure the coon and differential

More information

Additive Synthesis, Amplitude Modulation and Frequency Modulation

Additive Synthesis, Amplitude Modulation and Frequency Modulation Additive Synthesis, Aplitude Modulation and Frequency Modulation Pro Eduardo R Miranda Varèse-Gastproessor eduardo.iranda@btinternet.co Electronic Music Studio TU Berlin Institute o Counications Research

More information

Comparison Between PLAXIS Output and Neural Network in the Guard Walls

Comparison Between PLAXIS Output and Neural Network in the Guard Walls Coparison Between PLAXIS Output and Neural Network in the Guard Walls Ali Mahbod 1, Abdolghafar Ghorbani Pour 2, Abdollah Tabaroei 3, Sina Mokhtar 2 1- Departent of Civil Engineering, Shahid Bahonar University,

More information

5 Constellation for Digital Modulation Schemes

5 Constellation for Digital Modulation Schemes 5 Constellation for Digital Modulation Schees 5.1 PAM Definition 5.1. Recall, fro 3.6, that PAM signal wavefors are represented as s (t) = A p(t), 1 M where p(t) is a pulse and A A. 5.2. Clearly, PAM signals

More information

Windowing High-Resolution ADC Data Part 2

Windowing High-Resolution ADC Data Part 2 Windoing High-Resolution DC Data art Josh Carnes pplications Engineer, ational Seiconductor Corp. bstract nalyzing data fro DCs requires the use of indoing functions for spectral estiation and analysis

More information

Performance Analysis of an AMC System with an Iterative V-BLAST Decoding Algorithm

Performance Analysis of an AMC System with an Iterative V-BLAST Decoding Algorithm I. J. Counications, Network and Syste Sciences, 008,, 105-06 Published Online May 008 in SciRes (http://www.srpublishing.org/journal/ijcns/). Perforance Analysis of an AMC Syste with an Iterative V-BLAST

More information

UWB System for Time-Domain Near-Field Antenna Measurement

UWB System for Time-Domain Near-Field Antenna Measurement UWB Syste for Tie-Doain Near-Field Antenna Measureent B. Levitas #, M. Drozdov #, I. Naidionova #, S. Jefreov #, S. Malyshev *2, A. Chizh *3 www.geozondas.co # Geozondas Ltd., 6, Shevchenko Str., LT-3,

More information

The following tutorial will serve as an outline of the fundamental elements involved in the

The following tutorial will serve as an outline of the fundamental elements involved in the ACOUSTO-OPTICS TUTORIAL G. Ivtsenkov, Ph.D. & V. Pachkov, Ph.D. Light Manageent Group Inc. Research & Developent Burlington, Ontario, Canada INTRODUCTION THE ACOUSTO-OPTIC SWITCH PHYSICAL FUNDAMENTALS

More information

Exploring the Electron Tunneling Behavior of Scanning Tunneling Microscope (STM) tip and n-type Semiconductor

Exploring the Electron Tunneling Behavior of Scanning Tunneling Microscope (STM) tip and n-type Semiconductor Page 110 Exploring the of Scanning Tunneling Microscope (STM) tip and n-type Seiconductor M. A. Rahan * and J. U. Ahed Departent of Applied Physics, Electronics & Counication Engineering, University of

More information

Cross-correlation tracking for Maximum Length Sequence based acoustic localisation

Cross-correlation tracking for Maximum Length Sequence based acoustic localisation Cross-correlation tracking for Maxiu Length Sequence based acoustic localisation Navinda Kottege Research School of Inforation Sciences and Engineering The Australian National University, ACT, Australia

More information

Distributed Resource Allocation Assisted by Intercell Interference Mitigation in Downlink Multicell MC DS-CDMA Systems

Distributed Resource Allocation Assisted by Intercell Interference Mitigation in Downlink Multicell MC DS-CDMA Systems 1 Distributed Resource Allocation Assisted by Intercell Interference Mitigation in Downlin Multicell MC DS-CDMA Systes Jia Shi, Zhengyu Song, IEEE Meber, and Qiang Ni, IEEE Senior Meber Abstract This paper

More information

SPATIAL DIVERSITY TECHNIQUES IN MIMO WITH FREE SPACE OPTICAL COMMUNICATION

SPATIAL DIVERSITY TECHNIQUES IN MIMO WITH FREE SPACE OPTICAL COMMUNICATION SPATIAL DIVERSITY TECHNIQUES IN MIMO WITH FREE SPACE OPTICAL COMMUNICATION Ruchi Modi 1, Vineeta Dubey 2, Deepak Garg 3 ABESEC Ghaziabad India, IPEC Ghaziabad India, ABESEC,Gahziabad (India) ABSTRACT In

More information

Part 9: Basic AC Theory

Part 9: Basic AC Theory Part 9: Basic AC Theory 9.1 Advantages Of AC Systes Dealing with alternating current (AC) supplies is on the whole ore coplicated than dealing with DC current, However there are certain advantages of AC

More information

Keywords: Equivalent Instantaneous Inductance, Finite Element, Inrush Current.

Keywords: Equivalent Instantaneous Inductance, Finite Element, Inrush Current. Discriination of Inrush fro Fault Currents in Power Transforers Based on Equivalent Instantaneous Inductance Technique Coupled with Finite Eleent Method Downloaded fro ijeee.iust.ac.ir at 5:47 IRST on

More information

UNIT - II CONTROLLED RECTIFIERS (Line Commutated AC to DC converters) Line Commutated Converter

UNIT - II CONTROLLED RECTIFIERS (Line Commutated AC to DC converters) Line Commutated Converter UNIT - II CONTROLLED RECTIFIERS (Line Coutated AC to DC converters) INTRODUCTION TO CONTROLLED RECTIFIERS Controlled rectifiers are line coutated ac to power converters which are used to convert a fixed

More information

Radar Imaging of Non-Uniformly Rotating Targets via a Novel Approach for Multi-Component AM-FM Signal Parameter Estimation

Radar Imaging of Non-Uniformly Rotating Targets via a Novel Approach for Multi-Component AM-FM Signal Parameter Estimation Sensors 5, 5, 695-693; doi:.339/s53695 Article OPEN ACCESS sensors ISSN 44-8 www.dpi.co/journal/sensors Radar Iaging of Non-Uniforly Rotating Targets via a Novel Approach for Multi-Coponent AM-FM Signal

More information

Optical Cavity Designs for Interferometric Gravitational Wave Detectors. Pablo Barriga 17 August 2009

Optical Cavity Designs for Interferometric Gravitational Wave Detectors. Pablo Barriga 17 August 2009 Optical Cavity Designs for Interferoetric Gravitational Wave Detectors Pablo Barriga 7 August 9 Assignents.- Assuing a cavity of 4k with an ITM of 934 radius of curvature and an ETM of 45 radius of curvature.

More information