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PERFORMANCE OF FQPSK TRANSCEIVERS IN A COMPLEX REAL-LIFE INTERFERENCE ENVIRONMENTHaghdad, Mehdi, Feher, Kamilo 10 1900 (has links)
International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / The Bit Error Rate (BER) performance of FQPSK modulated signals in the presence of the Co-Channel
Interference (CCI) and Additive White Gaussian Noise (AWGN) is evaluated and improved. A Non-
Linearly Amplified (NLA) FQPSK modulated signal with the data rate of 1Mb/s and carrier frequency
of 70 MHz is interfered with a sinusoidal signal at different frequencies. As the relative distance of the
center frequency of the Co-channel interference (CCI) changes, different BER are obtained. The effect
of the CCI decreases as the CCI center frequency moves away from the center of the modulated signal.
In order to improve the BER in the presence of the CCI, a hard limited filter is added at the receiver
input. The hard limited filter has a different amplification factor for different signal strength. As a result,
the amplification factor for the CCI, which is normally a weaker signal, is smaller than the actual signal.
This means that the signal is amplified more than the interference and as a result the CCI is suppressed
and the BER rate improves. The results of both simulations and measurements are obtained for different
CCI center frequencies, before and after the improvements.
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DESIGN CONSIDERATIONS FOR DEVELOPMENT OF AN AIRBORNE FQPSK TRANSMITTERHorcher, Gregg 10 1900 (has links)
International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / This paper describes the design considerations used by Aydin Telemetry in the
development of its high data rate Feher Patented Quadrature Phase Shift Keying
(FQPSK) [1] frequency agile transmitter. We will address several key areas of interest to
the Telemetry community, such as the use of commercially available VLSI parts to
minimize parts count while maximizing reliability, adaptive filtering to accommodate a
wide range of data rates, and user selectable features to achieve a universal transmitter
design. User selectable features include differential encoder, 15 stage IRIG randomizer,
and 1/2 rate convolutional FEC coding. This paper also addresses the spectral efficiency
that can be achieved using a Class-C amplifier with FQPSK and the measured bit error
rate (BER) performance versus Eb/No.
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RADIO FREQUENCY OVERVIEW OF THE HIGH EXPLOSIVE RADIO TELEMETRY PROJECTBracht, Roger, Dimsdle, Jeff, Rich, Dave, Smith, Frank 10 1900 (has links)
International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / High explosive radio telemetry (HERT) is a project that is being developed jointly by Los
Alamos National Laboratory and AlliedSignal FM&T. The ultimate goal is to develop a
small, modular telemetry system capable of high-speed detection of explosive events,
with an accuracy on the order of 10 nanoseconds. The reliable telemetry of this data,
from a high-speed missile trajectory, is a very challenging opportunity. All captured data
must be transmitted in less than 20 microseconds of time duration. This requires a high
bits/Hertz microwave telemetry modulation code to insure transmission of the data within
the limited time interval available.
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IFM EFFECTS ON PCM/FM TELEMETRY SYSTEMSLaw, Gene, Whiteman, Don 10 1900 (has links)
International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / Incidental Frequency Modulation (IFM) products in telemetry transmitters can be a
significant cause of bit errors in received Pulse Code Modulation/Frequency Modulation
(PCM/FM) telemetry data. Range Commanders Council (RCC) and other documents give
little or no guidance as to acceptable levels of IFM for telemetry applications. The
expected higher vibration levels of future high velocity missile systems means that IFM
levels are likely to be higher than previously encountered.
This paper presents measured data on Bit Error Rate (BER) versus IFM levels at given
Signal to Noise Ratios (SNR’s) for PCM/FM telemetry systems. The information
presented can be utilized with BER versus SNR plots in the Telemetry Applications
Handbook, RCC Document 119, to determine the additional link margin required to
minimize IFM effects on telemetry data quality.
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EASTERN RANGE TITAN IV/CENTAUR-TDRSS OPERATIONAL COMPATIBILITY TESTINGBocchino, Chris, Hamilton, William 10 1900 (has links)
International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / The future of range operations in the area of expendable launch vehicle (ELV) support is
unquestionably headed in the direction of space-based rather than land- or air-based assets
for such functions as metric tracking or telemetry data collection. To this end, an effort
was recently completed by the Air Force’s Eastern Range (ER) to certify NASA’s
Tracking and Data Relay Satellite System (TDRSS) as a viable and operational asset to be
used for telemetry coverage during future Titan IV/Centaur launches. The test plan
developed to demonstrate this capability consisted of three parts: 1) a bit error rate test; 2)
a bit-by-bit compare of data recorded via conventional means vice the TDRSS network
while the vehicle was radiating in a fixed position from the pad; and 3) an in-flight
demonstration to ensure positive radio frequency (RF) link and usable data during critical
periods of telemetry collection. The subsequent approval by the Air Force of this approach
allows future launch vehicle contractors a relatively inexpensive and reliable means of
telemetry data collection even when launch trajectories are out of sight of land-based
assets or when land- or aircraft-based assets are not available for support.
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Test and Evaluation of Ultra High Spectral Efficient Feher Keying (FK)Lin, Jin-Song, Feher, Kamilo 10 1900 (has links)
International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Performances of a subclass of a new spectral efficient modulation scheme, designated as
Feher Keying [1], or FK, is evaluated. The Power Spectral Density (PSD) and Bit Error Rate
(BER) characteristics of FK are presented. FK has ultra high spectral efficiency and satisfies
the frequency mask for WLAN defined in FCC part 15, and it has a simple structure for high
bit rate implementation.
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Enhancing macrocell downlink performance through femtocell user cooperationZaid, Adem Mabruk 28 November 2011 (has links)
This thesis studies cooperative techniques that rely on femtocell user diversity to improve the downlink communication quality of macrocell users. We analytically analyze and evaluate the achievable performance of these techniques in the downlink of Rayleigh fading channels. We provide an approximation of both the bit-error rate (BER) and the data throughput that macrocell users receive with femtocell user cooperation. Using simulations, we show that under reasonable SNR values, cooperative schemes enhance the performances of macrocells by improving the BER, outage probability, and data throughput of macrocell users significantly when
compared with the traditional, non-cooperative schemes. / Graduation date: 2012
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Polar codes for compress-and-forward in binary relay channelsBlasco-Serrano, Ricardo, Thobaben, Ragnar, Rathi, Vishwambhar, Skoglund, Mikael January 2010 (has links)
We construct polar codes for binary relay channels with orthogonal receiver components. We show that polar codes achieve the cut-set bound when the channels are symmetric and the relay-destination link supports compress-and-forward relaying based on Slepian-Wolf coding. More generally, we show that a particular version of the compress-and-forward rate is achievable using polar codes for Wyner-Ziv coding. In both cases the block error probability can be bounded as O(2-Nβ) for 0 < β < 1/2 and sufficiently large block length N. / <p>© 2010 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. QC 20111207</p>
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Misbehaving relay detection for cooperative communications using a known or unknown distribution functionsWang, Sheng-Ming 11 January 2012 (has links)
In the cooperative communications, the users relay each other¡¦s signal and thus forming multiple transmission paths to the destination and therefore the system can achieve spatial diversity gain. Decode-and-forward and amplify-and-forward are the most popular relaying strategies in the literature due to their simplicity. However, in practice, cooperative users acting as relays may not always normally operated or trustworthy. When the relay misbehavior is present in
the cooperative networks, the communication performance may degrade dramatically and the users may be even better off without cooperation. Therefore, it is necessary for the destination to determine the misbehaving relays and to take appropriate actions to ensure that cooperative advantages are preserved. In this thesis, we focus on developing a misbehaving relay detection method to detect whether or not the system is in the presence of some misbehaving relays. After performing misbehaving relay detection, the destination removes the signals from the un-
reliable paths and then uses maximal ratio combing to achieve spatial diversity. The simulation results conducted by the thesis show that the proposed method is more robust as compared with those without employing misbehaving relay detection when the system is in the presence of some misbehaving relays.
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Misbehaving Relay Detection for Cooperative Communications without the Knowledge of Relay MisbehaviorsLi, Chieh-kun 17 July 2012 (has links)
In the cooperative communications, the users relay each other's signal and thus form multiple transmission paths to the destination and therefore the system can achieve spatial diversity gain.
Most studies in the literature assumed that cooperative users acting as the relays are normally operated and trustworthy. However, this may not always be true in practice. When the relay misbehaviors are present in the cooperative communications, the communication performance may degrade dramatically and the users may be even better off without cooperation. Therefore, it is necessary for the destination to determine the misbehaving relays and to take appropriate actions
to ensure that cooperative advantages are preserved.
This thesis considers both models in which the cooperative communications are with direct path (WDP) and without direct path (WODP).
Utilizing the proposed Kolmogorov-Smirnov test mechanism, the destination identifies the misbehaving relays within the cooperative
communications and then excludes their transmitting messages when performing the diversity combining to infer the symbols of interest sent by the source.
In addition, this thesis provides the bit error rate (BER) analysis of the cooperative communications
employing the proposed misbehaving relay detectors. The simulation results demonstrate that the proposed methods have robust performance when the relay misbehaviors are present in the cooperative communications.
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