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Showing papers on "Modulation published in 2000"


Journal ArticleDOI
TL;DR: Performance of time-hopping spread-spectrum multiple-access systems employing impulse signal technology for both analog and digital data modulation formats under ideal multiple- access channel conditions is estimated.
Abstract: Attractive features of time-hopping spread-spectrum multiple-access systems employing impulse signal technology are outlined, and emerging design issues are described. Performance of such communications systems in terms of achievable transmission rate and multiple-access capability are estimated for both analog and digital data modulation formats under ideal multiple-access channel conditions.

2,693 citations


Journal ArticleDOI
TL;DR: The lithium-niobate external-modulator technology meets the performance and reliability requirements of current 2.5-, 10-Gb/s digital communication systems, as well as CATV analog systems, and multiple high-speed modulation functions have been achieved in a single device.
Abstract: The current status of lithium-niobate external-modulator technology is reviewed with emphasis on design, fabrication, system requirements, performance, and reliability. The technology meets the performance and reliability requirements of current 2.5-, 10-, and 40-Gb/s digital communication systems, as well as CATV analog systems. The current trend in device topology is toward higher data rates and increased levels of integration. In particular, multiple high-speed modulation functions, such as 10-Gb/s return-to-zero pulse generation plus data modulation, have been achieved in a single device.

1,221 citations


Journal ArticleDOI
TL;DR: This work designs some multiple-antenna signal constellations and simulates their effectiveness as measured by bit-error probability with maximum-likelihood decoding and demonstrates that two antennas have a 6-dB diversity gain over one antenna at 15-dB SNR.
Abstract: Motivated by information-theoretic considerations, we propose a signaling scheme, unitary space-time modulation, for multiple-antenna communication links. This modulation is ideally suited for Rayleigh fast-fading environments, since it does not require the receiver to know or learn the propagation coefficients. Unitary space-time modulation uses constellations of T/spl times/M space-time signals (/spl Phi//sub i/, l=1, ..., L), where T represents the coherence interval during which the fading is approximately constant, and M

1,116 citations


Journal ArticleDOI
TL;DR: This work proposes a general approach to differential modulation for multiple transmit antennas based on group codes, which can be applied to any number of transmit and receive antennas, and any signal constellation, and can be demodulated with or without channel estimates.
Abstract: Space-time coding and modulation exploit the presence of multiple transmit antennas to improve the performance on multipath radio channels Thus far, most work on space-time coding has assumed that perfect channel estimates are available at the receiver In certain situations, however, it may be difficult or costly to estimate the channel accurately, in which case it is natural to consider the design of modulation techniques that do not require channel estimates at the transmitter or receiver We propose a general approach to differential modulation for multiple transmit antennas based on group codes This approach ran be applied to any number of transmit and receive antennas, and any signal constellation We also derive low-complexity differential receivers, error bounds, and modulator design criteria, which we use to construct optimal differential modulation schemes for two transmit antennas These schemes can be demodulated with or without channel estimates This permits the receiver to exploit channel estimates when they are available The performance degrades by approximately 3 dB when estimates are not available

944 citations


Journal ArticleDOI
TL;DR: The effects on the decision variables of the in-band distortion introduced by a bandpass memoryless nonlinearity can be described by means of a complex gain and an additive Gaussian term with zero mean and suitable variance; analytical expressions for gain and variance are given.
Abstract: This paper presents a theoretical characterization of nonlinear distortion effects in orthogonal frequency division multiplexing (OFDM) transmission systems. In the theoretical framework developed, it is shown that the effects on the decision variables of the in-band distortion introduced by a bandpass memoryless nonlinearity can be described by means of a complex gain and an additive Gaussian term with zero mean and suitable variance; analytical expressions for gain and variance are given. The conditions which allow this description are emphasized and discussed. As a consequence, a completely analytical procedure to evaluate error probability is also obtained and illustrated using OFDM/discrete multitone modulation (DMT) systems with rectangular pulse shaping; for the soft-envelope limiter nonlinearity, a closed form is derived. A comparison with simulation results is carried out to verify the accuracy of this method.

638 citations


Journal ArticleDOI
TL;DR: In this paper, the progress from simple gates using cross-gain modulation and four-wave mixing to the integrated interferometric gates using a cross-phase modulation is reviewed, which is very efficient for high-speed signal processing and open up interesting new areas, such as all-optical regeneration and high-time logic functions.
Abstract: Semiconductor optical amplifiers are useful building blocks for all-optical gates as wavelength converters and OTDM demultiplexers. The paper reviews the progress from simple gates using cross-gain modulation and four-wave mixing to the integrated interferometric gates using cross-phase modulation. These gates are very efficient for high-speed signal processing and open up interesting new areas, such as all-optical regeneration and high-speed all-optical logic functions.

520 citations


01 Jan 2000
TL;DR: In this paper, it is shown that inverters which have an odd number of levels can generate zero common-mode voltage by switching among certain states, and therefore motor bearing currents will be eliminated and conducted electromagnetic interference (EMI) will be reduced.
Abstract: It is well known that conventional two-level pulse-width modulated (PWM) inverters generate high frequency common-mode voltages with high dv/dt. Similarly, commonly used multilevel inverter modulation schemes generate common-mode voltages. Common-mode voltages may cause motor shaft voltages and bearing currents and conducted electromagnetic interference (EMI). Premature motor bearing failures and electronic equipment malfunctions have been reported to be directly related to bearing currents and EMI. In this paper, approaches to eliminating common-mode voltage when using multilevel PWM inverters are presented. It is shown that inverters, which have an odd number of levels, will generate zero common-mode voltage by switching among certain states. Therefore motor bearing currents will be eliminated and conducted EMI will be reduced. Both sine-triangle intersection modulation (SPWM) and space-vector modulation (SVM) schemes are discussed and detailed comparative simulation results between conventional and novel modulation schemes are provided.

431 citations


Journal ArticleDOI
TL;DR: By using this scheme, the mean square values of the symbol timing estimation error can be decreased by several orders of magnitude compared to the common correlation methods in both the AWGN and multipath fading channels.
Abstract: Orthogonal frequency division multiplexing (OFDM) is an effective modulation technique for high-rate and high-speed transmission over frequency selective fading channels. However, OFDM systems can be extremely sensitive and vulnerable to synchronization errors. In this paper, we present a scheme for performing timing recovery that includes symbol synchronization and sampling clock synchronization in OFDM systems. The scheme is based on pilot subcarriers. In the scheme, we use a path time delay estimation method to improve the accuracy of the correlation-based symbol synchronization methods, and use a delay-locked loop (DLL) to do the sampling clock synchronization. It is shown that by using this scheme, the mean square values of the symbol timing estimation error can be decreased by several orders of magnitude compared to the common correlation methods in both the AWGN and multipath fading channels. In addition, the scheme can track the symbol timing drift caused by the sampling clock frequency offsets.

297 citations


Journal ArticleDOI
TL;DR: Some novel multilevel PWM strategies to take advantage of the multiple levels in both a diode-clamped inverter and a cascaded H-bridges inverter by utilizing all of the levels in the inverter even at low modulation indices are proposed.
Abstract: When utilized at low amplitude modulation indices, existing multilevel carrier-based PWM strategies have no special provisions for this operating region, and several levels of the inverter go unused. This paper proposes some novel multilevel PWM strategies to take advantage of the multiple levels in both a diode-clamped inverter and a cascaded H-bridges inverter by utilizing all of the levels in the inverter even at low modulation indices. Simulation results show what effects the different strategies have on the active device utilization. A prototype 6-level diode-clamped inverter and an 11-level cascaded H-bridges inverter have been built and controlled with the novel PWM strategies proposed in this paper.

234 citations


Proceedings ArticleDOI
08 Oct 2000
TL;DR: In this paper, the inherent relations between sine-triangle and space-vector pulsewidth modulation schemes for three-level voltage-source inverters were studied and it was shown that the two schemes can function equivalently through proper selection of common-mode injections in the case of sine triangle modulation, or dwell times in equivalent redundant switching states in a space vector modulation scheme.
Abstract: This paper studies the inherent relations between sine-triangle and space-vector pulsewidth modulation schemes for three-level voltage-source inverters. It is shown that the two schemes can function equivalently through proper selection of common-mode injections in the case of sine-triangle modulation, or dwell times in equivalent redundant switching states in the case of space-vector modulation. Simulation and measurement results illustrate that understanding of these relations can lead to a more efficient and flexible three-level modulator with desired or optimal performance.

229 citations


Journal ArticleDOI
TL;DR: This work demonstrates that fuzzy c-means clustering is capable of robust recovery of the unknown constellation and proposes to use constellation shape as a robust signature for digital modulation recognition.

Patent
21 Dec 2000
TL;DR: In this article, the first long code and the second long code are transmitted at an in-phase (I) and at a quadrature-phase(Q) angle, respectively, on the carrier signal using radio waves.
Abstract: A system for rapidly acquiring a spreading code, used in a code division multiple access (CDMA) system, comprises a generator for generating a first long code and a second long code, with each long code having a length of N chips. The first long code is different from the second long code. A transmitter transmits the first long code and the second long code at a first phase angle and at a second phase angle, respectively, on a carrier signal over a communications channel using radio waves. The first long code and the second long code may be transmitted at an in-phase (I) angle and at a quadrature-phase (Q) angle, respectively, on the carrier signal. From the communications channel, an I acquisition circuit and a Q acquisition circuit may acquire, in parallel, the first long code and the second long code from the I angle and the Q angle, respectively, of the carrier signal by searching, in parallel, N/2 chips of the first long code and the second long code.

09 Jul 2000
TL;DR: In this article, the first all-optical 100 Gbit/s wavelength conversion employing cross-phase modulation is demonstrated with a recently introduced completely integrated and packaged delayed-interference configuration.
Abstract: First all-optical 100 Gbit/s wavelength conversion employing cross-phase modulation is demonstrated with a recently introduced completely integrated and packaged delayed-interference configuration.

Journal ArticleDOI
TL;DR: In this paper, the authors concentrate on the parametric mixing of a signal waveform with a linearly chirped optical pump as the time lens mechanism and analyze all single-lens system configurations including sum-and difference-frequency mixing schemes with positive and negative group velocity dispersions using temporal ray diagrams as an aid in understanding their operation.
Abstract: The recently developed process of temporal imaging expands or compresses time waveforms while preserving the shapes of their envelope profiles. A key element in a temporal imaging system is a time lens which imparts a quadratic phase modulation to the waveform being imaged. Several methods, such as electrooptic modulation, can be used to produce the phase modulation. In this paper, we concentrate on the parametric mixing of a signal waveform with a linearly chirped optical pump as the time lens mechanism. We analyze all single-lens system configurations including sum- and difference-frequency mixing schemes with positive and negative group velocity dispersions using temporal ray diagrams as an aid in understanding their operation.

Journal ArticleDOI
TL;DR: In this paper, the authors report all-optical 100 Gbit/s wavelength conversion employing cross-phase modulation for the first time, and they use a cross-photon-based modulation scheme.
Abstract: The authors report all-optical 100 Gbit/s wavelength conversion employing cross-phase modulation for the first time

Journal ArticleDOI
TL;DR: In this paper, a novel configuration of resonator microoptic gyro (MOG), which is monolithically integrated on silica planar lightwave circuit (PLC) with countermeasures for noise factors, is reported.
Abstract: We report a novel configuration of resonator microoptic gyro (MOG), which is monolithically integrated on silica planar lightwave circuit (PLC) with countermeasures for noise factors. Optical ring-resonator gyros suffer mainly from polarization fluctuation induced noise and backscattering induced noise. We discuss eigenstate of polarization in the waveguide to clarify behavior of the former and propose a countermeasure with control of the waveguide birefringence. As for the latter, binary phase shift keying (B-PSK) with a special signal processing is proposed. Thermooptic (TO) phase modulation is the only one scheme to apply B-PSK in the silica waveguide, whose bandwidth is limited to /spl sim/1 KHz. To utilize the narrow bandwidth of the TO modulator effectively, we propose an electrical signal processing scheme and a modulation waveform to compensate the frequency response. By constructing an experimental setup, suppression of the backscattering induced noise is demonstrated, and the gyro output is observed with applying an equivalent rotation.

Patent
01 Sep 2000
TL;DR: In this paper, the authors proposed a system for underground acoustic signals from an acoustic source, which includes a plurality of laser sources, each emitting light at different frequencies, and a number of optical sensors, receiving and altering the light in response to acoustic waves.
Abstract: A system for sensing subterranean acoustic waves emitted from an acoustic source includes a plurality of laser sources, each emitting light at different frequencies; a plurality of subterranean optical sensors, receiving and altering the light in response to acoustic waves; at least one optical detector, receiving the altered light and outputting an electrical signal; and electronics, receiving the electrical signal and converting it into seismic data format. Light from the optical sources is modulated at a plurality of modulation frequencies. The electronics can demodulate the signal by mixing the signal with periodic waveforms having frequencies corresponding to one and two times the modulation frequencies. The modulation frequencies are selected such that at least one of the second harmonic frequencies associated with the modulation frequencies is interleaved in a non-interfering manner within the corresponding set of first harmonic frequencies, and preferably such that at least one of the first harmonic frequencies is interleaved in a non-interfering manner within the corresponding set of modulation frequencies. The hydrophone for sensing the acoustic signals is able to operate at pressures and temperatures of at least 5,000 psi and 130° C., respectively. The hydrophone may be housed in a cable having a diameter less than about 1.5 inches. The hydrophone's sensor preferably includes a reference mandrel, two sensing mandrels, and a telemetry cam, which are aligned in a coaxial, end-to-end configuration to reduce the profile of the hydrophone. The mandrels have hemispherically-shaped endcaps and are joined by flexible interlinks having grooves for receiving optical fiber.

Patent
06 Dec 2000
TL;DR: In this paper, a transmit-configuration mechanism for configuring an FEC encoder (34) including an associated interleaver (84) for changing data channel characteristics is presented.
Abstract: A transmit-configuration mechanism (52) for configuring an FEC encoder (34) (including an associated interleaver (84)) for changing data channel characteristics Channel information specifying a modulation mode and carriers capable of supporting the modulation mode for the data channel is received by a transmitting network node (12a) for use in a data transmission to a receiving network node (12b) The received channel information is based on a prior data transmission to the receiving network node (12b) over the data channel Configuration values are computed from the received channel information and an amount of data to be transmitted in a data transmission The FEC encoder (34) is configured to operate on the data transmission data amount according to the configuration information

Patent
08 Sep 2000
TL;DR: In this article, a stacked-carrier spread spectrum communication system based on frequency domain spreading that multiplies a time-domain representation of a baseband signal by a set of superimposed, or stacked, complex sinusoid carrier waves is proposed.
Abstract: A “stacked-carrier” spread spectrum communication system based on frequency domain spreading that multiplies a time-domain representation of a baseband signal by a set of superimposed, or stacked, complex sinusoid carrier waves. In a preferred embodiment, the spreading energizes the bins of a large fast Fourier transform (FFT). This provides a considerable savings in computational complexity for moderate output FFT sizes. Point-to-multipoint and multipoint-to-multipoint (nodeless) network topologies are possible. A code-nulling method is included for interference cancellation and enhanced signal separation by exploiting the spectral diversity of the various sources. The basic system may be extended to include multi-element antenna array nulling methods also for interference cancellation and enhanced signal separation using spatial separation. Such methods permit directive and retrodirective transmission systems that adapt or can be adapted to the radio environment. Such systems are compatible with bandwidth-on-demand and higher-order modulation formats and use advanced (maximum-SINR) despreader adaptation algorithms.

Patent
Neil Daly1
22 Jun 2000
TL;DR: In this paper, a cellular radio communication system is provided for transmitting data over a plurality of transmission links, which includes means for generating a modulated signal by applying a constant amplitude envelope modulation scheme to data to be transmitted across poor quality transmission links and amplifier means for non-linearly amplifying the modulated signals.
Abstract: A cellular radio communication system is provided for transmitting data over a plurality of transmission links. The system includes means for generating a modulated signal by applying a constant amplitude envelope modulation scheme to data to be transmitted across poor quality transmission links and amplifier means for non-linearly amplifying the modulated signal. The system can additionally include means for generating a second modulated signal by applying an amplitude dependent modulation scheme to data to be transmitted across higher quality transmission links and amplifier means for linearly amplifying the second modulated signal. Using a constant amplitude envelope modulation scheme, such as GMSK or MLCAM for poorer quality links means that for these links signals can be amplifier non-linearly at higher gains.

Proceedings ArticleDOI
27 Nov 2000
TL;DR: A novel all-digital IRMA scheme and its discrete-time equivalent model that relies on pulse-amplitude modulation (PAM) and judiciously designed orthogonal user codes to eliminate MUI deterministically and account for frequency-selective multipath in the downlink is developed.
Abstract: Impulse radio (IR) is an ultra-wideband system with attractive features for baseband asynchronous multiple-access (MA), multimedia services, tactical wireless communications and networking. Implemented with analog components, the continuous-time IRMA model utilizes pulse-position modulation (PPM) and random time-hopping codes to alleviate multipath effects and suppress multiuser interference (MUI). We develop here a novel all-digital IRMA scheme and its discrete-time equivalent model that relies on pulse-amplitude modulation (PAM) and judiciously designed orthogonal user codes to eliminate MUI deterministically and account for frequency-selective multipath in the downlink. We also design a time-division-duplex access protocol and low-complexity linear multichannel receivers that we compare and test both analytically and by simulation.

Journal ArticleDOI
TL;DR: It is shown that the properties of the basis functions have no effect on the noise performance of a modulation scheme, provided that the energy per bit is constant, and the concept of waveform communications is generalized.
Abstract: In wireless local area networks and indoor communications, multipath propagation limits the performance of data communications systems. To overcome the multipath propagation problem, a spread spectrum system has to be used. The chaotic communications technique, where inherently wideband chaotic basis functions are used, offers a cheap alternative to conventional spread spectrum communications. Unfortunately, analytic expressions for the noise performance of chaotic modulation schemes are not available in the literature. This has so far prevented a full exploitation of the features of chaotic modulation schemes. By generalizing the waveform communications concept, this paper develops exact expressions for the noise performance of the coherent antipodal chaos shift keying (CSK), coherent differential chaos shift keying (DCSK), and differentially coherent DCSK modulation schemes. We show that the properties of the basis functions have no effect on the noise performance of a modulation scheme, provided that the energy per bit is constant. In this sense, the concept of waveform communications is generalized. Finally, our theoretical results are verified by computer simulations.

Journal ArticleDOI
TL;DR: A comparative investigation on the use of random modulation schemes for DC/DC power converters is presented, addressing the effectiveness of randomness level on spreading the dominating frequencies that normally exist in constant-frequency PWM schemes, and the low-frequency power spectral density (PSD) of each scheme.
Abstract: A comparative investigation on the use of random modulation schemes for DC/DC power converters is presented. The modulation schemes under consideration include randomized pulse position modulation, randomized pulsewidth modulation (PWM) and randomized carrier-frequency modulation with fixed and variable duty cycle. The paper emphasizes the suitability and applicability of each scheme in DC/DC power converters. Issues addressed include the effectiveness of randomness level on spreading the dominating frequencies that normally exist in constant-frequency PWM schemes, and the low-frequency power spectral density (PSD) of each scheme. The validity of the analyses is confirmed experimentally by using a DC/DC buck converter operating in the continuous conduction mode. The PSD of the output under each scheme is presented and compared.

Journal ArticleDOI
TL;DR: This three-part paper shows in a tutorial manner how the theory of conventional telecommunications systems can be applied to chaotic modulation schemes and discusses the latest results in the field of chaotic communications.
Abstract: For pt. II, see ibid., vol. 45, p. 1129-40 (1998). In a digital communications system, data is transmitted from one location to another by mapping bit sequences to symbols, and symbols to sample functions of analog waveforms. The analog waveform passes through a bandlimited (possibly time-varying) analog channel, where the signal is distorted and noise is added. In a typical conventional system, the analog sample functions sent through the channel are weighted sums of one or more sinusoids, called basis functions; in a chaotic communications system, the sample functions are segments of chaotic waveforms. This three-part paper shows in a tutorial manner how the theory of conventional telecommunications systems can be applied to chaotic modulation schemes. In addition, it discusses the latest results in the field of chaotic communications. In Part III, examples are given of chaotic communications schemes with and without synchronization, and the performance of correlator-based systems is evaluated in the context of noisy, bandlimited channels.

Patent
30 Mar 2000
TL;DR: In this article, the transmission system changeover decision section 110 stores the number of times of receiving the OK signal or the NG signal, decides whether or not revising a transmission system depending on the frequency of reception of the received signal or an NG signal and outputs an instruction as to whether the transmission transmission system is to be revised.
Abstract: PROBLEM TO BE SOLVED: To provide a radio communication equipment that conducts communication with a communication system corresponding to a change in channel. SOLUTION: A separate section 109 separates an output signal from a demodulation section 108 into received data and an OK signal or an NG signal, provides an output of the received data and an output of the OK signal or the NG signal to a transmission system changeover decision section 110. The transmission system changeover decision section 110 stores the number of times of receiving the OK signal or the NG signal, decides whether or not revising a transmission system depending on the frequency of reception of the OK signal or the NG signal and outputs an instruction as to whether or not the transmission system is to be revised to a transmission system changeover control section 111. The transmission system changeover control section 111 controls a transmission frame generating section 102, a modulation section 103, a transmission wireless section 104 and an antenna multicoupler section 105 to instruct a buffer 101 to output transmission data for re-transmission when the revision of the transmission system is required according to the instruction from the transmission system changeover discrimination section 110. COPYRIGHT: (C)2001,JPO

Patent
08 Dec 2000
TL;DR: In this paper, a method for communicating information using ultra wideband impulse radio transmitter and receiver is described, which includes the steps of generating and transmitting a series of time-modulated pulse outputted from I and J channels, each pulse delayed by of four pre-determined time delay periods corresponding to points (M1, M2, M3, or M4) and representative of at least two data bits of information.
Abstract: A method for communicating information is using ultra wideband impulse radio transmitter and receiver. The method includes the steps of generating and transmitting a series of time-modulated pulse outputted from I and J channels, each pulse delayed by of four pre-determined time delay periods corresponding to points (M1, M2, M3, or M4) and representative of at least two data bits of information, and receiving and demodulating the series of time-modulated pulses (I, J) to estimate the data bits associated with each pulse.

Proceedings ArticleDOI
23 Jun 2000
TL;DR: In this paper, the importance of the vector sequence on the IGBT switching voltages in order to reduce switching losses of the current source converter (CSC) bridge is discussed.
Abstract: A PWM current source frequency converter is an alternative to control variable speed AC-drives instead of commonly used voltage source frequency converters. Space vector control techniques are widely adopted for high performance drives while the control system is most conveniently implemented by microprocessors, microcontrollers and DSPs. Space vector pulse width modulation is also an appropriate technique for the phase current modulation of a current source converter (CSC). Either "5-switch" or "4-switch" space vector modulation can be used, the latter being perhaps more popular. Different modulation strategies can be developed by selecting an appropriate vector sequence for the switching cycle. Therefore this paper discusses the significance of the vector sequence on the IGBT switching voltages in order to reduce switching losses of the CSC bridge. An optimal vector modulation strategy, which minimizes the switching losses of the CSC bridge, is developed and analyzed in detail. Finally, the results are verified by PSpice(R) simulations.

Patent
27 Oct 2000
TL;DR: The trellis encoder as discussed by the authors is a convolutional encoder operable to sequentially group data to provide coded bits to provide QPSK symbols, which allows de-multiplexing to take place after coding and modulation has been performed.
Abstract: The evolution of high rate data services within future wireless networks will call for new RF access technologies to enable substantial increases in overall system spectral efficiency at an acceptably low cost to the user. Space-Time Coding (STC) is an antenna array processing technology currently simulating considerable Interest across the wireless industry. The invention provides a space-time coding apparatus having an input, a trellis encoder, a modulator, a demultiplexer, and a set of signal outputs wherein the input is operable to receive a stream of data. This allows de-multiplexing to take place after coding and modulation has been performed. The trellis encoder comprises a convolutional encoder operable to sequentially group data to provide coded bits to provide QPSK symbols. By the selection of convolutional encoder rates and/or modulation alphabets STCs of any desired dimensionality may be produced including multi-dimensional codes.

Journal ArticleDOI
TL;DR: In this article, a theoretical and experimental analysis of the performance of a single chirped fiber grating is presented in order to compare their performance and suitability for beamforming applications in microwave antennas.
Abstract: We present a theoretical and experimental analysis of the performance of phased-array antennas steered by a single chirped fiber grating. Two approaches consisting of conventional and single-sideband (SSB) modulation techniques of the optical signal are presented in order to compare their performance and suitability for beamforming applications in microwave antennas. By using a 40-cm-long chirped grating, we measure the phase and amplitude response and calculate the corresponding radiation patterns to demonstrate wide-band operation and continuous spatial scanning properties of both configurations. SSB modulation Is presented as a real alternative to the first one offering broader operation band (4-18 GHz) for a given chirped grating and being less demanding on the fiber grating characteristics.

Journal ArticleDOI
TL;DR: In this article, the authors present the first demonstration of a millimeter-wave broadband fiber-wireless system which incorporates baseband data transmission in both the downstream (622 Mb/s) and upstream (155 Mbps/s), where the local oscillator (LO) required at the remote antenna base station for up and down conversion to/from the mm-wave radio frequency (RF) is delivered remotely via a modulation scheme that is tolerant to the effects of fiber chromatic dispersion on the detected LO carrier power.
Abstract: We present the first demonstration of a millimeter-wave (mm-wave) broadband fiber-wireless system which incorporates baseband data transmission in both the downstream (622 Mb/s) and upstream (155 Mb/s) directions. The local oscillator (LO) required at the remote antenna base station for up- and downconversion to/from the mm-wave radio frequency (RF) is delivered remotely via a modulation scheme that is tolerant to the effects of fiber chromatic dispersion on the detected LO carrier power. The technique employs a single dual electrode modulator located at the central office (CO) and the data and an RF signal at a frequency equal to half the LO frequency, are applied simultaneously to the device. The modulation scheme was optimized as a function of the modulator operating conditions. Simultaneous bidirectional radio transmission in the mm-wave fiber-wireless network was implemented using specially designed mm-wave diplexers located at the base station (BS) and customer unit, and a single Ka-band printed antenna array at the BS operating simultaneously in transmit and receive mode. Error-free data transmission was demonstrated for both down(34.8 GHz) and uplinks (37.5 GHz) after 20 km of single-mode optical fiber and a bit error rate (BER) of 10/sup -6/ was achieved after the inclusion of a 2-m radio link.