CPM Modulation Research Articles

CPM modulation implementation using blind equalizer and non-coherent demodulation for 5G and beyond

CPM modulation implementation using blind equalizer and non-coherent demodulation for 5G and beyond

Improvement of bit error rate performance of MC-CDMA system by using adaptive digital modulation schemes

In Wireless Communication, the transmission channel suffers due to multipath propagation and channel dispersion due to Inter Symbol Interference (ISI), thereby degrades the system performance greatly. Future communication requires high data rate and effective utilization of bandwidth. Hence, there is a need to improve the Bit Error Rate (BER). The proposed work is Adaptive Modulation (AM), combined with Multi Carrier Code Division Multiple Access (MC-CDMA) based transmission system. It is a promising way to increase the data rate and it uses bandwidth in a efficient manner. The Adaptive Modulation based MC-CDMA systems applied to a wide-area environment, can achieve high data rate up to 100Mbps. In this paper M-ary PSK, M-ary QAM and M-ary CPM modulation techniques are used. The Adap-tive modulation based MC-CDMA systems perform well for around 10 number of users. As a whole, the adaptive MC-CDMA system is found to give the optimum BER performance of given digital modulation schemes for fourth generation environment.

Power Spectrum Density of Single Side Band CPM Using Lorenztian Frequency Pulses

We propose a new waveform for frequency-shift keying continuous phase modulation (FSK-CPM) that directly generates a single side band (SSB) spectrum. The original principle, inspired from quantum physics (levitons), is presented. From the simple analytical form of the modulation, orthonormal wave-functions and analytical expressions leading to the SSB power spectrum density are proposed. This CPM modulation displays a very compact spectrum, with 99% of the power in the primary bandwidth. Its SSB property makes this FSK-CPM scheme, hereby called SSB-FSK, a promising solution not sensitive to image frequency degradation and would allow large bit rates transmission at low carrier frequency.

A Constellation Space Dimensionality Reduced Sub-Optimal Receiver for Orthogonal STBC CPM Modulation in a MIMO Channel

We consider burst orthogonal space-time block coded (OSTBC) CPM modulation in a MIMO flat slow Rayleigh fading channel. The optimal receiver must process a multidimensional non-linear CPM signal on each antenna. This task imposes a high load on the receiver computational performance and increases its complexity. We analytically derive a suboptimal receiver with a reduced number of front end matched filters (MFs) corresponding to the CPM dimension. Our derivation is made fully in the constellation signal space, and the reduction is based on the linear orthogonal projection to the optimal subspace. Criterion optimality is a standard space-time rank and determinant criterion. The optimal arbitrary-dimensional subspace search leads to the eigenvector solution. We present the condition on a sufficient subspace dimension and interpret the meaning of the corresponding eigenvalues. It is shown that the determinant and rank criterion for OSTBC CPM is equivalent to the uncoded CPM Euclidean distance criterion. Hence the proposed receiver may be practical for uncoded CPM and foremost in a serially concatenated (SC) CPM system. All the derivations are supported by suitable error simulations for binary 2REC h= 1/2, but the procedure is generally valid for any CPM variant. We consider OSTBC CPM in a Rayleigh fading AWGN channel and SC CPM in an AWGN channel.

Symbol timing estimation with CPM modulation

Symbol timing in continuous phase modulated signals is investigated making use of maximum likelihood estimation methods. Nondata-aided algorithms are proposed with a feedforward structure. They are suitable for digital implementation and can be employed with either full or partial response signaling. Multilevel symbol alphabets are allowed and the modulation index may be arbitrary. The performance is assessed by analysis and simulation. It turns out that full response schemes are comparatively easier to synchronize. Difficulties arise with partial response signaling especially with long frequency pulses.