Supportive wireless communication relay network in OFDMbased systems have shown to expand performance in countless system using digital modulation techniques as a form of spatial diversity, but are not gladly available cp-operative variety for M –ary QAM OFDM based system where the best relay only participates in the relaying. In this paper we compute the error rate performance of cooperative V...

This paper studies the multiple relays amplify-and-forward (AF) cooperative communication system with adaptive continuous (ACR) and discrete rate (ADR) M-QAM modulation in Rayleigh fading channel. The average spectral efficiency of the fixed ACR, ADR M-QAM schemes with various number of relays are researched and analyzed. We first obtain quantitative spectral efficiency loss for the fixed rate ...

In this paper, the diversity gain of a Maximal Ratio Combiner (MRC) has been investigated for Orthogonal Frequency Division Multiplexing (OFDM) by varying the number of receiving antennas. Different modulation schemes namely 64-PSK, 64-QAM, 16-PSK, 16-QAM and QPSK have been used in OFDM technique. The simulation results show that the performance (SNR) of an OFDM system can be significantly impr...

The combination of powerful error correcting codes such as (LDPC) codes and Quadrature Amplitude Modulation (QAM) has been widely deployed in wireless communication standards such as the IEEE 802.11n and DVB-T2. Recently, several Unequal Error Protection schemes which exploit non-uniform degree distribution of bit nodes in irregular LDPC codes have been proposed. In parallel, schemes that explo...

In this paper, a joint solution is proposed with RS coding, OFDM, and PAPR clipping. We implemented the hybrid method which consists of RS coding and adaptive clipping technique over an additive white Gaussian noise (AWGN) channel. Reed Solomon RS (255, 239) coding can correct 8 symbol errors from 239 symbols data. This capability can effectively compensate for the performance degradation resul...

A new construction for multilevel coded modulation with multistage decoding and unequal error protection is proposed and analyzed for both symmetric and asymmetric 16-QAM constellations. It is shown that the conventional upper bound originally derived for PSK signaling is loose when applied to QAM. A new tight approximated upper bound is proposed for 16-QAM and the partitioning considered. The ...

Error vector magnitude (EVM) as a performance metric for M-ary quadrature amplitude modulation (QAM) formats in optical coherent systems is presented. It shown that the calibrated BER, which would otherwise be under-estimated without correction factor, can reliably monitor of near target BER 10?3 phase shift keying (QPSK), 16-QAM, and 64-QAM employing carrier recovery with differential decoding...

In this letter , super-orthogonal space-time trellis codes (SOSTTC) are extended for quadrature amplitude modulation (QAM) constellations. A systematic set-partitioning method for QAM constellations is given. Furthermore, trellis shaping based on set partitioning is incorporated in SOSTTC with QAM symbols to achieve extra shaping gain. Peak constraints can be used to limit the constellation exp...

A carrier synchronization algorithm for high-order QAM modulated signals that uses Kalman filtering techniques shows fast acquisition times and good frequency tracking performances. The algorithm relies on a decision directed extended Kalman filter combined with a lock detector which determines the status of the synchronization process, modifying consequently the filter parameters. Simulations ...