Continuous phase modulation

About: Continuous phase modulation is a research topic. Over the lifetime, 3199 publications have been published within this topic receiving 37245 citations. The topic is also known as: CPM.

Error probability of partial-response continuous-phase modulation with coherent MSK-type receiver, diversity, and slow Rayleigh fading in Gaussian noise

Abstract: This paper considers a class of constant-amplitude modulation schemes with good spectral main lobe and tail behavior. Detection is assumed to be coherent and the receiver is of offset-quadrature type, i.e., minimum shift keying (MSK) type, consisting of a linear filter in each quadrature arm followed by simple processing. Analytical error-probability formulas are derived for various modulation schemes and receiver filters for ideal diversity with maximal-ratio and selection combining. Independent slow Rayleigh fading in Gaussian noise is assumed and several numerical examples are given. Asymptotic behavior of the error probability for large signal-to-noise ratios is derived, and the relationship between the degree of smoothing in the partial-response continuous-phase modulation and the asymptotic error probability is shown for fading channels with and without diversity.

Trellis termination in CPM

Abstract: A technique is presented for terminating the encoder of continuous phase modulation (CPM) into a known trellis state. This is useful when block-wise a posteriori probability processing is employed, e.g. in iterative ("turbo") receivers for serially concatenated CPM.

Noise radar using random phase and frequency modulation

Abstract: Pulse compression radar is used in a great number of radar applications. Excellent range resolution and high ECCM performance can be achieved by wide-band modulated long pulses, which spread out the transmitted energy in frequency and time. By using random noise as waveform, the range ambiguity can be suppressed as well. The same limit in Doppler resolution is achieved as for a coherent Doppler radar when the time compression of the reference is tuned to that of the target. Mostly, the random signal is transmitted directly from a noise generating HF-source. A sine wave, which is phase or frequency modulated by random noise, is an alternative giving similar performance but higher transmitted mean power when peak-limited transmitters are applied. A narrower modulation noise bandwidth can also be applied to generate the same output bandwidth. For phase modulation, the bandwidth amplifying factor is simply the rms value of the phase modulation, and for a frequency modulating waveform, the output rms bandwidth equals the rms-value of the frequency modulation. The results also show that the range sidelobes can be highly suppressed compared with the sidelobes of the modulating signal. The mean and variance of the correlation integral are derived in terms of the autocorrelation function of the modulation. The combined effects of low range sidelobes and enhanced range resolution make frequency and phase modulation attractive.

Adaptively-equalized digital receiver with carrier tracking

Abstract: A method of carrier tracking in a digital receiver includes adjusting the phase of an equalized signal by a phase correction to compensate for a carrier frequency offset. For a small carrier frequency offset the phase correction is based on a first estimate of phase error and phase velocity of the equalized signal. For a large carrier frequency offset the first phase velocity estimate is controlled by a second phase velocity estimate based on rotation of the data constellation.

Multi-layer differential phase shift keying with bit-interleaved coded modulation and OFDM

Abstract: An efficient system and method for modulation and demodulation to achieve a high data rate using Bit-Interleaved Coded Modulation and OFDM uses either a coherent or a non-coherent transmission scheme using differential modulation. In order to maintain a high data rate impervious to sudden phase changes, a communication system uses an efficient constellation having multiple rings with different sizes and modulation/demodulation schemes utilizing this constellation. In power line communications, the channel gain information is obtained easily at a receiver (100) while the phase information is not. Thus, the communication system uses an absolute magnitude and differential phase coding for modulation and demodulation of the signals.