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Showing papers on "Continuous phase modulation published in 2012"


Journal ArticleDOI
TL;DR: Two novel linewidth-tolerant, low-complexity feedforward carrier phase estimation algorithms are described for dual-polarization 16-ary quadrature-amplitude-modulation with coherent detection.
Abstract: Two novel linewidth-tolerant, low-complexity feedforward carrier phase estimation algorithms are described for dual-polarization 16-ary quadrature-amplitude-modulation with coherent detection. For both algorithms, the carrier phase is estimated in two stages. The first stage employs either a simplified quadrature-phase-shift-keying (QPSK) partitioning algorithm or the blind phase search (BPS) algorithm. The second stage employs a novel QPSK constellation transformation algorithm. The performance and linewidth tolerance of both algorithms are evaluated using experimental and simulation data, and the hardware complexity is assessed. For both proposed two-stage algorithms, the linewidth symbol duration product is 1.3 × 10-4 for a 1 dB penalty in optical signal-to-noise ratio at a bit error ratio of 10-3. This performance is comparable to a single-stage BPS algorithm with a large number of test phases, but with a reduction of the hardware complexity by factors of about 2.5-11.

81 citations


Journal ArticleDOI
Ruichen Tao1, Xinhuan Feng1, Yuan Cao1, Zhaohui Li1, Bai-Ou Guan1 
TL;DR: In this paper, a single bandpass microwave photonic filter (MPF) based on phase modulation and stimulated Brillouin scattering (SBS) was proposed and demonstrated, and the operation principle of the filter is based on the concept of using the Brillouins selective sideband amplification to achieve effective PM to amplitude modulation (AM) conversion.
Abstract: We propose and demonstrate a widely tunable single bandpass microwave photonic filter (MPF) based on phase modulation (PM) and stimulated Brillouin scattering (SBS). The operation principle of the filter is based on the concept of using the Brillouin selective sideband amplification to achieve effective PM to amplitude modulation (AM) conversion. Only when one of the phase modulated sidebands lies in the SBS gain spectrum, can PM-to-AM conversion occur and the corresponding PM frequency be detected. Whereas the phase modulated sidebands lie out of the SBS gain spectrum, there is no RF signal obtained due to the -phase difference. As a result, a bandpass filter centered at a special frequency can be achieved. By adjustment of the Brillouin pump wavelength, tunable single bandpass MPF can be obtained. In the experiment, a microwave photonic filter with narrow bandwidth of about 35 MHz and a tuning range of 20 GHz has been obtained.

58 citations


Proceedings ArticleDOI
23 Apr 2012
TL;DR: In this paper, a technique is developed for reconstructing a continuous phase time history from the non-continuous phase bursts of time division multiple access (TDMA) signals, which facilitates exploitation of TDMA signals as signals of opportunity (SOPs) within an opportunistic navigation framework.
Abstract: A technique is developed for reconstructing a continuous phase time history from the noncontinuous phase bursts of time division multiple access (TDMA) signals. A continuous phase time history facilitates exploitation of TDMA signals as signals of opportunity (SOPs) within an opportunistic navigation framework. Because of their widespread use and availability in today's wireless communication market, TDMA signals are attractive candidate SOPs for opportunistic navigation. The phase reconstruction technique presented here combines an integer least squares technique for estimating phase ambiguities at the beginning of each TDMA phase burst with a Kalman filter and smoother for removing these ambiguities and optimally “stitching” the bursts together. A Monte-Carlo-type simulation and test environment has been developed to investigate the sensitivity of the proposed phase reconstruction technique to various system parameters, namely, carrier-to-noise ratio, receiver clock quality, TDMA transmitter clock quality, line-of-sight acceleration uncertainty, and TDMA burst structure. Simulation results indicate that successful carrier phase reconstruction is most strongly dependent on the TDMA burst period and on the combined phase random walk effect of the receiver and transmitter clocks, the propagation effects, and the range errors.

44 citations


Patent
13 Feb 2012
TL;DR: In this article, a finite range phase modulator modulates a phase of a continuous wavelength channel light in accordance with the analog drive signal, to generate a modulated channel light for transmission through the optical communications system.
Abstract: A transmitter in an optical communications system includes a digital signal processor for processing a data signal to generate a sample stream encoding successive symbols in accordance with a constrained phase modulation scheme having a constellation of at least two symbols and a modulation phase constrained to a phase range spanning less than 4π. A digital-to-analog converter converts the sample stream into a corresponding analog drive signal. A finite range phase modulator modulates a phase of a continuous wavelength channel light in accordance with the analog drive signal, to generate a modulated channel light for transmission through the optical communications system. A receiver in the optical communications system includes an optical stage for detecting phase and amplitude of the modulated channel light and for generating a corresponding sample stream, and a digital signal processor for processing the sample stream to estimate each successive symbol of the modulated channel light.

44 citations


Proceedings ArticleDOI
07 May 2012
TL;DR: A modification to the code search strategy known as Marginal Fisher's Information (MFI) is presented that enables this greedy approach to further improve upon the performance of the resulting CPM-implemented continuous waveform in terms of range sidelobes.
Abstract: Ongoing work is exploring the optimization of physical radar emissions based on the continuous phase modulation (CPM) implementation of polyphase codes. Here a modification to the code search strategy known as Marginal Fisher's Information (MFI) is presented that enables this greedy approach to further improve upon the performance of the resulting CPM-implemented continuous waveform in terms of range sidelobes. The optimization process is also expanded to include the effects of the transmitter (from both modeled and physical hardware perspectives) to facilitate the optimization of physical emissions that are specifically tuned to the transmitter. This approach is particularly useful for high-power transmitters in which the actual physical emission is a spectrally modified and non-linearly distorted version of the intended radar waveform.

32 citations


Journal ArticleDOI
TL;DR: Spread-spectrum continuous-phase-modulated (SS-CPM) signals are investigated with application to satellite navigation, with main output that setting the modulation index h<;1 to semi-integer values allows the SS-C PM signals to behave like having subcarriers, exactly in the same way as it happens for the binary offset carrier (BOC) modulation.
Abstract: Spread-spectrum continuous-phase-modulated (SS-CPM) signals are investigated with application to satellite navigation. In particular, focus is devoted to the special subclasses of SS-CPM with semi-integer modulation index h greater than one. This constitutes a novelty with respect to traditional navigation signal design on one hand (which is based on direct-sequence spread-spectrum (DS-SS) signals with rectangular pulse) and with traditional communication SS-CPM with h>;1 on the other. Main output is that setting the modulation index h<;1 to semi-integer values allows the SS-CPM signals to behave like having subcarriers, exactly in the same way as it happens for the binary offset carrier (BOC) modulation. The main advantage is that CPM ensures a constant envelope at the transmission side, thus being appealing when these features are required at the system level. After a description of signal properties, focus is devoted to ranging code synchronization, by exploitation of the theory on time-delay estimation (TDE). A few delay-lock loop schemes are also presented, based on an offset quadrature phase-shift keying (OQPSK) approximation of the signal at the receiver side, achieved by Laurent's decomposition at the receiver side. Proposed loops performance are analyzed in terms of Cramer-Rao bound (CRB), rms tracking error, and multipath robustness. An application of SS-CPM for a two-rate-service scheme is proposed.

30 citations


Proceedings ArticleDOI
Yangyang Fan1, Liang Dou1, Zhenning Tao1, Li Lei1, Shoichiro Oda1, Takeshi Hoshida1, Jens C. Rasmussen1 
16 Sep 2012
TL;DR: In this paper, the phase noise induced by the intra-channel nonlinearity with DP-16QAM was found to be higher than that with DPQPSK in 1600km transmission experiments.
Abstract: The phase noise induced by the intra-channel nonlinearity with DP-16QAM is found to be higher than that with DP-QPSK in 1600km transmission experiments. The main reason is identified as the large IXPM in 16QAM based on the proposed nonlinear model.

27 citations


Journal ArticleDOI
TL;DR: The generation of continuous phase masks designed to generate a set of target diffraction orders with defined relative intensity weights is reported, and the same phase map is extended to other phase patterns such as vortex generating/sensing gratings.
Abstract: We report the generation of continuous phase masks designed to generate a set of target diffraction orders with defined relative intensity weights. We apply a previously reported analytic calculation that requires resolving a single equation with a set of parameters defining the target diffraction orders. Then the same phase map is extended to other phase patterns such as vortex generating/sensing gratings. Results are demonstrated experimentally with a parallel-aligned spatial light modulator.

26 citations


Proceedings ArticleDOI
01 Dec 2012
TL;DR: An X-band reflection-type phase shifter with full 360° continuous phase shift, low insertion loss, and low gain deviation using standard 0.15µm HEMT process is demonstrated in this paper.
Abstract: An X-band reflection-type phase shifter (RTPS) with full 360° continuous phase shift, low insertion loss, and low gain deviation using standard 0.15-µm HEMT process is demonstrated in this paper. Two circuit implementation techniques are employed: π-type reflection loads and folded Lange coupler. The π-type reflection loads and the folded Lange coupler are utilized in one stage reflection-type phase shifter to cover more than 180° phase tuning. Cascade of two stage RTPS is adopted to achieve 360° phase tuning. Measurements show signal losses of 6.4dB±1.4dB including pad loss, low gain deviation of 0.8 dB, and a 360° continuously tunable range across 11∼13 GHz with 0-mW dc power consumption. To the best of our knowledge, the proposed phase shifter has the highest FOM of 46.2(°/dB), among all reported 360° X-band CMOS phase shifters.

25 citations


Journal ArticleDOI
TL;DR: Simulation results show that the proposed chaotic interleaving scheme can greatly improve the performance of the CPM-SC-FDE system and provides a good trade-off between system performance and bandwidth efficiency.
Abstract: In this paper, we propose a chaotic interleaving scheme for the continuous phase modulation based single-carrier frequency-domain equalization (CPM-SC-FDE) system. Chaotic interleaving is used in this scheme to generate permuted versions from the sample sequences to be transmitted, with low correlation among their samples, and hence a better bit error rate (BER) performance can be obtained. The proposed CPM-SC-FDE system with chaotic interleaving combines the advantages of the frequency diversity, the low complexity, and the high power efficiency of the CPM-SC-FDE system and the performance improvements due to chaotic interleaving. The BER performance of the CPM-SC-FDE system with and without chaotic interleaving is evaluated by computer simulations. Also, a comparison between the proposed chaotic interleaving and the conventional block interleaving is performed. Simulation results show that, the proposed chaotic interleaving scheme can greatly improve the performance of the CPM-SC-FDE system. Furthermore, the results show that this scheme outperforms the conventional block interleaving scheme in the CPM-SC-FDE system. The results also show that, the proposed CPM-SC-FDE system with chaotic interleaving provides a good trade-off between system performance and bandwidth efficiency.

21 citations


Patent
17 Dec 2012
TL;DR: In this article, an apparatus and method for transmitting a signal needed for beam acquisition in a wireless communication system operating in a super-high frequency band is provided, in which a small reference modulation symbol length relative to a data modulation symbols length is determined, taking into account a communication characteristic of a mobile station.
Abstract: An apparatus and method for transmitting a signal needed for beam acquisition in a wireless communication system operating in a super-high frequency band are provided, in which a small reference modulation symbol length relative to a data modulation symbol length is determined, taking into account a communication characteristic of a Mobile Station (MS), a data modulation symbol generated by modulating a data signal using a predetermined modulation scheme is transmitted according to the determined data modulation symbol length, and a reference modulation symbol generated by modulating a reference signal using the predetermined modulation scheme is transmitted according to the determined reference modulation symbol length.

Proceedings ArticleDOI
01 Sep 2012
TL;DR: In this article, a photonic approach was proposed to generate a frequency-quadrupled millimeter-wave (mm-wave) signal with tunable phase shift, which can find applications in broadband and high frequency beamforming systems and array signal processing systems.
Abstract: We propose and demonstrate a novel photonic approach to generating a frequency-quadrupled millimeter-wave (mm-wave) signal with tunable phase shift. This approach has a unique feature that combines frequency-quadrupling and continuous phase tuning, which can find applications in broadband and high frequency beamforming systems and array signal processing systems.

Journal ArticleDOI
TL;DR: An efficient scheme of extended irregular repeat-accumulate (eIRA-) coded minimum shift keying (MSK) is presented, incorporating a continuous-phase encoder decomposed from MSK, which obtains lower complexity and less decoding latency because all differential encoders in the eIRA code are eliminated, while adding some differential decoders.
Abstract: An efficient scheme of extended irregular repeat-accumulate (eIRA-) coded minimum shift keying (MSK) is presented. Based on an extrinsic information transfer (EXIT) chart, it is designed as an eIRA code, incorporating a continuous-phase encoder (CPE) decomposed from MSK. Our scheme and a contrasting scheme of another eIRA-coded MSK are simulated in an additive white Gaussian noise (AWGN) channel. Simulation results show that our scheme outperforms the contrasting scheme by about 2 dB at a bit error rate (BER) of and has the same performance of an optimal eIRA-coded binary phase shift keying (BPSK). In addition, our scheme obtains lower complexity and less decoding latency because all differential encoders in the eIRA code are eliminated, while adding some differential decoders. Thus, the two-level Tanner graph-based decoding in the contrasting scheme is reduced. Therefore, the proposed scheme can be efficiently applied to satellite and deep space communications.

Proceedings ArticleDOI
01 Dec 2012
TL;DR: In this paper, a K-band phase shifter with low insertion-loss variation fabricated with the TSMC standard 0.18-μm 1P6M CMOS technology is presented.
Abstract: This paper presents a K-band phase shifter with low insertion-loss variation fabricated with the TSMC standard 0.18-μm 1P6M CMOS technology. Low insertion loss variation is achieved by using impedance matching of the reflective load. To achieve a phase control range of 360°, a different 180° phase switch-type phase shifter (STPS) is applied to the output of a 180° continuous phase control range reflection-type phase shifter (RTPS). In this design, the layer of the bottom metal (M1) as the ground plane is used to minimize the substrate loss. The measured results show that the insertion loss variation in the phase control range is less than 1.2 dB, and the phase control range is 275° at 23 GHz. The chip size is 0.45 mm2 with pads and with no power consumption.

Journal ArticleDOI
TL;DR: A symbol-by-symbol coherent optical receiver employs a novel, complex-weighted, decision-aided, maximum-likelihood (CW-DA-ML) carrier phase and frequency offset estimator, which achieves a complete modulo-R reduced frequency offset estimation (FOE) range of ± R/2.
Abstract: We present a symbol-by-symbol coherent optical receiver, which employs a novel, complex-weighted, decision-aided, maximum-likelihood (CW-DA-ML) carrier phase and frequency offset estimator. The CW-DA-ML carrier estimator uses a CW transversal filter to generate a carrier reference phasor, and the filter weights are automatically adapted on-line by linear regression on the observed signals. A complete modulo-R reduced frequency offset estimation (FOE) range of ±R/2 is achieved, independent of modulation format, where R is the symbol rate. Carrier phase and frequency tracking is achieved rapidly. The acquisition speed of frequency offset in quaternary phase-shift keying (4-PSK) signals is more than 5 times faster than that of differential FOE. A constant penalty of approximately 1 dB at bit-error rate of 10−4 is demonstrated for all frequency offsets in 4-PSK signals with laser-linewidth-symbol-duration product of 8×10−5.

18 Apr 2012
TL;DR: In this article, a new sinusoidal PWM inverter suitable for use with power MOSFETs is described, and the output waveforms in the proposed PWM transform are investigated both theoretically and experimentally.
Abstract: paper a new sinusoidal PWM inverter suitable for use with power MOSFETs is described. . The output waveforms in the proposed PWM inverter are investigated both theoretically and experimentally. The fundamental component of the three-phase line-to-line voltage is increased by about 15 percent above than that of the conventional sine-wave inverter. The sinusoidal PWM switching scheme allows control of the magnitude and the frequency of the output voltage. Therefore, the input to the PWM inverters is an uncontrolled, essentially constant dc voltage source. This switching scheme results in harmonic voltage in the range of the switching frequency and higher, which can be easily filtered out. This Paper proposes several carrier based modulation techniques for full bridge inverter. In this paper, various pulse width modulation techniques are implemented, which can minimize the total harmonic distortion and enhances the output voltages. The methodologies adopting the constant switching frequency, variable switching frequency multicarrier, phase shifted carrier pulse width modulation concepts are implemented in this paper. The above methodologies divided in to two techniques, triangular carrier and sawtooth carrier for gate signal generation. In this paper, simulation of three phase inverter using sawtooth waveform as carrier signal has been done. Another method using asymmetrical modulation technique with triangular waveform as a carrier signal has been done. KeywordsInverter, Sawtooth waveform, Triangular waveorm, Matlab

Journal ArticleDOI
TL;DR: Two new iterative multiuser detection algorithms for spectrally efficient frequency division multiple access continuous phase modulation in additive white Gaussian noise are presented, performing approximate maximum a posteriori (MAP) bit detection.
Abstract: This paper presents two new iterative multiuser detection algorithms for spectrally efficient frequency division multiple access continuous phase modulation in additive white Gaussian noise. The detectors are derived from the sum-product algorithm and the factor graph framework, performing approximate maximum a posteriori (MAP) bit detection. A factor graph of the actual multiuser detection problem is considered, rather than only factor graphs of the individual single user detection problems combined with ad-hoc inter-user interference cancellation. The practical implementation of the detectors is based on the assumption that a suitable set of sum-product messages can be approximated by a Gaussian distribution. This methodology allows to considerably reduce the computational complexity and memory size requirements as compared to a straightforward application of the sum-product rules. The proposed algorithms further succeed in achieving a good error performance.

Journal ArticleDOI
Shuo Liu1, Wen Xiao1, Feng Pan1, Fanjing Wang1, Lin Cong1 
TL;DR: A quality map is derived directly from the reconstructed complex amplitude distribution of object wave to evaluate noise influence and phase reliability in the wrapped phase image and quality-guided phase unwrapping algorithm is implemented with the quality map to retrieve continuous phase profile.

Patent
28 Nov 2012
TL;DR: In this paper, a quick carrier synchronizing method for FSK (Frequency Shift Key) signal coherent demodulation is proposed, which comprises the steps: 1) carrying out a demodulating operation for a received lead sequence by using a lead sequence waveform generated locally or pre-stored when a receiver detects that the lead sequence arrives in a transmission process of a physical layer to obtain a single-frequency signal with continuous phase.
Abstract: The invention discloses a quick carrier synchronizing method for FSK (Frequency Shift Key) signal coherent demodulation, which comprises the steps: 1) carrying out a demodulating operation for a received lead sequence by using a lead sequence waveform generated locally or pre-stored when a receiver detects that the lead sequence arrives in a transmission process of a physical layer to obtain a single-frequency signal with continuous phase; 2) estimating the frequency and phase of the section of the single-frequency signal through estimation of the frequency and phase of the single-frequency signal; and 3) eliminating the frequency deviation and phase of a received frame to obtain a received signal with synchronized carrier according to the estimated value. In the transmission process of the physical layer, after the lead sequence is received, the frequency deviation and phase information comprised in the received lead sequence is adequately extracted and the frequency deviation and phase are applied to compensation of the frequency deviation and phase of all received data by current frame so that coherent demodulation can be possibly applied to the receiver, thereby, the overall receiving performance of the receiver is further improved.

Proceedings ArticleDOI
01 Sep 2012
TL;DR: Simulations give the behaviour of six-phase systems with discontinuous synchronized modulation, including combined schemes of discontinuous PWM, which allow continuous phase voltages synchronization during the whole control range.
Abstract: Algorithms of discontinuous synchronized pulsewidth modulation (PWM), including combined schemes of discontinuous PWM, have been applied for synchronous control of four inverters feeding six-phase drive on the base of asymmetrical induction motor which has two sets of windings spatially shifted by 30 electrical degrees. The proposed schemes of synchronized PWM allow continuous phase voltages synchronization during the whole control range. Simulations give a behaviour of six-phase systems with discontinuous synchronized modulation.

Proceedings ArticleDOI
10 Jun 2012
TL;DR: This paper addresses detailed waveform trade-offs for mesh satellite networks by considering spectral efficiency, resilience against non linear distortion, channel impairments and interference for both linear and continuous phase modulation schemes defined in the DVB-RCS2 standard.
Abstract: This paper addresses detailed waveform trade-offs for mesh satellite networks. The waveform analysis is carried out considering spectral efficiency, resilience against non linear distortion, channel impairments and interference for both linear and continuous phase modulation schemes defined in the DVB-RCS2 standard.

Proceedings Article
31 Dec 2012
TL;DR: To improve the Power Amplifier (PA) energy efficiency, a Polarization-Amplitude-Phase Modulation (PAPM) scheme in wireless communication, which introduces the signal's Polarization State, amplitude and phase as the information-bearing parameter, is proposed.
Abstract: To improve the Power Amplifier (PA) energy efficiency, a Polarization-Amplitude-Phase Modulation (PAPM) scheme in wireless communication, which introduces the signal's Polarization State (PS), amplitude and phase as the information-bearing parameter, is proposed. Since that the transmitted signal's PS can be completely determined by a pair of orthogonal dual-polarized antennas and is unaffected by the PA, using the PS as the information-carrying parameter can further increase the data rate and allow PA to work in its non-linear region. Thus, the PA energy efficiency can be enhanced. On the basis of the above, to optimize the PA energy efficiency, an optimization problem regarding the output back off value and the ratio between the data carried by the PS and the amplitude-phase has been formulated, and the distribution of the optimum solutions is presented. The simulation results show that, with the same symbol error rate and channel state, PAPM can reduce the energy consumption per bit by 50% compared with QAM on average.

Patent
04 Jul 2012
TL;DR: In this article, a multivariate position random polar MCP-EBPSK (Multivariate Continuous Phase-Extended Binary Phase Shift Keying) modulation and demodulation method is proposed, which is based on a corrected random polar continuous phase-extended binary phase shift keying modulation mode.
Abstract: The invention discloses a multivariate position random polar MCP-EBPSK (Multivariate Continuous Phase-Extended Binary Phase Shift Keying) modulation and demodulation method, which is based on a corrected random polar continuous phase-extended binary phase shift keying modulation mode. The method involves a multivariate position random polar MCP-EBPSK modulator and a multivariate position random polar MCP-EBPSK signal demodulator. The multivariate position random polar MCP-EBPSK modulator is used for carrying out corrected random polar continuous phase keying to different phase modulation periods of sine wave carriers according to multivariate information symbols; and the multivariate position random polar MCP-EBPSK signal demodulator comprises an impulse filter used for highlighting the phase modulation information of received signals and eliminating the polar change of the received signals so that the demodulation performance is not influenced by the modulation of the multivariate position random polar. In the invention, the transmission rate and the spectrum utilization rate of a random polar CP-EBPSK communication system are multiplied by modulation signals, and the system has narrow occupied bandwidth, wide code rate application range, good demodulation performance and good flexibility for use.

Journal ArticleDOI
TL;DR: In this paper, a new pulse width modulation (PWM) strategy, with the view to ensure that the power devices at all the levels are switched equal number of times, is proposed.
Abstract: The number of switching per modulation cycle at each level in a multi-level inverter depends on the carrier frequency and the duration that the reference waveform dwells within the level. The variable carrier frequency band (VFCB) approach creates as many clusters as the number of carrier frequencies and consequent deterioration of the harmonic spectrum. Therefore, a new pulse width modulation (PWM) strategy, with the view to ensure that the power devices at all the levels are switched equal number of times, is proposed in this paper. It is designed such that the frequency of the carrier waves is allowed to remain constant for the chosen application while maintaining the number of switching for all devices is same. The MATLAB-based simulation response and its experimental validation are included to highlight the fact that there is a significant enhancement in harmonic power distribution besides contributing to reduce the switching losses and improve the efficiency.

Journal ArticleDOI
TL;DR: The experiments illustrate the robust of the feature-based approach for automatic digital modulation classification and a higher recognition probability suitable to various pulse shaping filters, roll-off factors and symbol rates.
Abstract: Classifications of digital modulation, the signal characteristics of the phase of the cycle will cause the phase wrapped and reduce overlapping signals in the received RF digital modulation automatically correct classification probability According to the principle of minimum mean square, a phase modulation and phase modulation signal classification features as well as 2PSK and MPSK classification The experiments illustrate the robust of the feature-based approach for automatic digital modulation classification and a higher recognition probability suitable to various pulse shaping filters, roll-off factors and symbol rates DOI: http://dxdoiorg/1011591/telkomnikav10i81666

Proceedings Article
24 Dec 2012
TL;DR: In this article, the authors introduce the principles of the newly defined NBWF and point out some unapparent spectrum usage issues of the current proposal, which is based on Continuous Phase Modulation (CPM).
Abstract: In order to fulfill most of the military operational requirements, two kinds of waveforms are needed, a wideband networking waveform, e.g. the Coalition Wideband Networking waveform (COALWNW) with high data rates, enabling network centric warfare and a Narrow Band Waveform (NBWF) covering long ranges and enabling the parallel transmission of data and voice. As a complement to COALWNW, the NATO Line of Sight Communications Capability Team is developing a new NBWF. Legacy versions of the NBWF exist as national waveforms only, operating historically in the VHF tactical communications band ranging from 30 MHz to 88 MHz occupying a channel bandwidth of 25 kHz. The new NBWF is expected to operate in the same frequency range, employing the same channelization; furthermore, the NBWF should allow operation in the tactical UHF band as well. The current waveform proposal is based on Continuous Phase Modulation (CPM), which is widely used in mobile communications, due to the constant envelope property of the modulation scheme. In this paper, we first introduce principles of the newly defined NBWF. Furthermore, we want to point out some unapparent spectrum usage issues of the current proposal.

Proceedings ArticleDOI
01 Jul 2012
TL;DR: Numerical results confirm that the proposed algorithms can generate the distance spectra of all systems with lower complexity relative to previous methods and are particularly suited for multi user CPM systems.
Abstract: The performance of maximum likelihood detection of a coded modulation scheme over an additive white Gaussian noise channel can be predicted precisely by its Euclidean distance spectrum. In this paper, three algorithms are developed to generate the Euclidean distance spectra. The first algorithm is an exhaustive tree-search algorithm which is simplified by exploiting the correspondence between a code tree and the trellis. This algorithm is then modified to incorporate the A∗ algorithm and results in two heuristic algorithms. Moreover, the technique of trellis minimization is further developed for the multi user case and employed to reduce the complexity and memory requirements. Numerical results confirm that the proposed algorithms can generate the distance spectra of all systems with lower complexity relative to previous methods and are particularly suited for multi user CPM systems.

Journal ArticleDOI
TL;DR: In this paper, a computer-based active interferometer stabilization method that can be set to an arbitrary phase difference and does not rely on modulation of the interfering beams is presented.
Abstract: We present a computer-based active interferometer stabilization method that can be set to an arbitrary phase difference and does not rely on modulation of the interfering beams. The scheme utilizes two orthogonal modes propagating through the interferometer with a constant phase difference between them to extract a common relative phase and generate a linear feedback signal. Switching times of 50 ms over a range of 0–6π radians at 632.8 nm are experimentally demonstrated. The relative interferometer phase can be stabilized up to several days to within ± 3°.

Proceedings ArticleDOI
10 Jun 2012
TL;DR: This work considers a frequency-division-multiplexed satellite system where nonlinear distortions may originate from the presence of high power nonlinear devices and can cause significant performance degradations and uses the spectral efficiency as a performance measure to compare different transmission strategies and modulation formats.
Abstract: We consider a frequency-division-multiplexed satellite system where nonlinear distortions may originate from the presence of high power nonlinear devices and can cause significant performance degradations. The spectral efficiency is used as a performance measure to compare, from an information-theoretic point of view, different transmission strategies and modulation formats. More precisely, we will consider transmission schemes employing continuous phase modulations, which are robust to nonlinearities, and schemes based on linear modulations and employing a detector taking into account the nonlinear effects or more traditional techniques, such those based on predistortion of the nonlinear device.

Journal ArticleDOI
TL;DR: In this paper, a pair of polarity-reversed 24 GHz millimeter-wave (MMW) ultra-wideband (UWB) monocycles were generated by using delay interferometer (DI) based phase modulation to intensity modulation (PM-IM) conversion and carrier suppression modulation (CSM) based frequency up-conversion.