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.

A method of non-data-aided carrier recovery with modulation identification

Abstract: A non-data aided carrier recovery technique using modulation format identification is proposed. This technique can also be interpreted as a modulation identification method that is robust against static phase and frequency offsets. The performance of the proposed technique is studied and analytical expressions derived for the mean acquisition time to detect lock in the cases of M-PSK, M=2,4,8, and 16-QAM modulation, with respect to frequency offset and signal-to-noise ratio. The results are verified with Monte Carlo simulations. The main advantage of the proposed method lies in its simpler implementation and faster lock detection, when compared to conventional methods.

Continuous phase modulation encoder for wireless networks

Abstract: Various example embodiments are disclosed herein. According to an example embodiment, an apparatus for use in a wireless transmitter may include a phase encoder adapted to generate a continuous time signal based on a symbol and a corresponding modulation index for a current symbol interval and one or more previous symbol intervals and based on a continuous phase modulation (CPM) phase response function, a filter and symbol-rate sampler adapted to filter and then symbol rate sample the continuous time signal to generate a symbol-rate statistic that is representative of the continuous time signal for each of the symbol intervals; a mapping circuit adapted to map each of the plurality of symbol-rate statistics to a corresponding constant modulus CPM symbol, and a transmitter circuit adapted to transmit a signal based on the constant modulus CPM symbols.

Continuous-Phase Modulations for CDMA Radio Communications: Modem Architecture and Performance

Abstract: In this paper we analyze the structure and the performance of a digital modem for band-limited spread-spectrum signals to be employed in a radio communication network with asynchronous code-division multiple access and constant-envelope continuous-phase modulation. After a description of the modem structure and the evaluation of its bit error rate in the presence of co-channel interference, we tackle the key point of code synchronization. In particular, we present a detailed analysis of the code acquisition strategy, assessing its performance in terms of false alarm probability, missed detection probability and mean acquisition time. Furthermore, we address the problem of code chip timing recovery, describing the performance of three different code tracking loops in terms of the steady-state RMS chip timing error jitter. The analytical approach we present can be applied to any Continuous Phase Modulation (CPM) format that can be approximated by an Offset-QAM signal, such as Gaussian-filtered Minimum-Shift Keying (GMSK).

An Array of Coherent Sources Based on Novel Dual-Loop PLL Infrastructure

Abstract: In this paper, a novel array of coherent sources based on dual-loop phase-locked loop (PLL) is proposed. An advanced low-cost frequency and phase control technique for a group of PLLs is presented. A novel dual-loop PLL infrastructure consists of a conventional PLL loop and a microcontroller-unit-controlled phase-detector-array loop, which achieves real-time calibration on both frequency and phase by reducing the effect of component aging and environmental issues. This technique has its advantages of building a phased transmitter array. For the purpose of demonstration, a four-element phased array has been designed and implemented by using commercially available components at S-band. Near-perfect local oscillator (LO) beamforming performance and array pattern self-compensation realization are presented and analyzed. Due to analog continuous phase control and individual programmable transmit frequency, the dual-loop PLL-based coherent-source array in this paper offers considerable practical advantages when implementing beamforming, as compared to other beamforming techniques.

On Joint Source and Channel Coding Using Trellis Coded CPM: Analytical Bounds on the Channel Distortion

Abstract: Joint source and channel coding (JSCC) using trellis coded quantization (TCQ) in conjunction with trellis coded continuous phase modulation (CPM) is studied. The channel is assumed to be the additive white gaussian noise (AWGN) channel. Analytical bounds on the channel distortion for the investigated systems with maximum-likelihood sequence detection (MLSD) are developed. The bounds are based on the transfer function technique, which was modified and generalized to include continuous-amplitude discrete-time signals. For a memoryless uniform source, the constructed bounds for the investigated systems are shown to be asymptotically tight for increasing channel signal-to-noise ratio (SNR) values. For a memoryless nonuniform source, the constructed bounds are not as tight as the one for the uniform source, however, it still can be used as an indication to how the system performs. It is concluded that the minimum Euclidean distance of the system alone is not enough to evaluate the performance of the considered systems. The number of error events having minimum Euclidean distance and the total distortion caused by those error events also affect the asymptotic performance. This work provides an analysis tool for the investigated systems. The analysis method is very general. It may be applied to any trellis based JSCC schemes.