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.

Channel estimation and equalization for CPM with application for aeronautical communications via a satellite link

Abstract: In this paper, we present a generalized polyphase representation for Continuous Phase Modulation (CPM) signals suited to the detection over frequency-selective channels. We first develop two different equalizers based on this representation and relate them to the State of Art. We also derive a Least Squares (LS) channel estimation and an improved LS estimation using a priori on the channel. Simulation results show the equivalence between existing equalizers and also show that our channel estimation leads only to a small degradation in term of Bit Error Rate (BER) in the case of an aeronautical communication over a satellite link.

Optimization of CPM Pragmatic Capacity

Abstract: The paper extends the pragmatic approach to coded continuous-phase modulation (CPM). It first proposes an optimization of the CPM capacity for given complexity and bandwidth efficiency. Then, the best CPM schemes are embedded into a pragmatic coded-modulation scheme, whose pragmatic capacity (a.k.a. BICM capacity) is maximized through a careful design of the mapping between input bits and CPM waveforms. The so obtained CPM schemes show a pragmatic capacity very close to the CPM capacity. An outer binary serially-concatenated convolutional code, cascaded with the CPM modulator through an interleaver, yields performance close to the pragmatic (and so to the CPM) capacity without requiring iterations between outer code and CPM modulator.

Symbol timing tracking for continuous phase modulation over fast flat-fading channels

Abstract: The symbol timing tracking problem for a class of continuous phase modulation (CPM) schemes transmitted over unfaded and fast flat-fading channels is studied. The specific family of CPM considered is that of M-ary continuous-phase modulation with a modulation index of h=1/M. A particular symbol synchronizer structure that constructs a tone at the symbol frequency by passing the received signal through an Mth power law nonlinearity and multiband filter followed by a squared-envelope nonlinearity and narrowband filter is proposed. The operation and parameters of this symbol synchronizer are discussed as well as the performance of the synchronizer. Simulation results giving the root-mean-square timing jitter of this system for several binary, quaternary and 8-ary instances of modulation using rectangular, raised-cosine, truncated Nyquist III, and truncated tamed FM pulse shapes are presented to illustrate the synchronizer performance. >

Exploiting Intelligent Reflecting Surfaces in NOMA Networks: Joint Beamforming Optimization

Abstract: This paper investigates a downlink multiple-input single-output intelligent reflecting surface (IRS) aided non-orthogonal multiple access (NOMA) system, where a base station (BS) serves multiple users with the aid of IRSs Our goal is to maximize the sum rate of all users by jointly optimizing the active beamforming at the BS and the passive beamforming at the IRS, subject to successive interference cancellation decoding rate conditions and IRS reflecting elements constraints In term of the characteristics of reflection amplitudes and phase shifts, we consider ideal and non-ideal IRS assumptions To tackle the formulated non-convex problems, we propose efficient algorithms by invoking alternating optimization, which design the active beamforming and passive beamforming alternately For the ideal IRS scenario, the two subproblems are solved by invoking the successive convex approximation technique For the non-ideal IRS scenario, constant modulus IRS elements are further divided into continuous phase shifts and discrete phase shifts To tackle the passive beamforming problem with continuous phase shifts, a novel algorithm is developed by utilizing the sequential rank-one constraint relaxation approach, which is guaranteed to find a locally optimal rank-one solution Then, a quantization-based scheme is proposed for discrete phase shifts Finally, numerical results illustrate that: i) the system sum rate can be significantly improved by deploying the IRS with the proposed algorithms; ii) 3-bit phase shifters are capable of achieving almost the same performance as the ideal IRS; iii) the proposed IRS-aided NOMA systems achieve higher system sum rate than the IRS-aided orthogonal multiple access system

Zero Crossing Modulation for Communication with Temporally Oversampled 1-Bit Quantization

Abstract: Today's communication systems typically use high resolution analog-to-digital converters (ADCs). However, considering future communication systems with data rates in the order of 100Gbit/s the ADC power consumption becomes a major factor due to the high sampling rates. A promising alternative are receivers based on 1-bit quantization and oversampling w.r.t. the signal bandwidth. Such an approach requires a redesign of modulation, receiver synchronization, and demapping. A zero crossing modulation is a natural choice as the information needs to be carried in the zero crossing time instants. The present paper provides an overview on zero crossing modulation, achievable rates, sequence mapping and demapping, 1-bit based channel parameter estimation, and continuous phase modulation as an alternative zero crossing modulation scheme.