OFDM forms the basis for all the 4G wireless technologies which ensures multi carrier modulation. Fading nature of a wireless channel due to constructive/destructive interference degrades the performance of the system. The spectral efficiency and performance gain can be improved by adapting data rate/modulation schemes. We introduce Adaptive Bit-interleaved coded modulation (ABICM) in OFDM usin...

In the past decades, researchers/scientists have paid attention to physical layer of underwater communications (UWCs) due a variety scientific, military, and civil tasks completed beneath water. This includes numerous activities critical for communication, such as survey monitoring oceans, rescue, response disasters under sea. Till end last decade, many review articles addressing history UWC be...

Coded modulation with APSK is proposed for OFDM-based VLC systems. Simulation results show that the proposed scheme achieves better performance than conventional QAM counterpart in both DCO-OFDM and ACO-OFDM systems, while similar complexity is maintained. OCIS codes: (060.2605) Free-space optical communication; (060.4080) Modulation.

This paper proposes an analytical model for evaluating the performance of dense wavelength division multiplexing (DWDM) for all optical orthogonal frequency division multiplexing (AO-OFDM) optical wireless channel. The investigated performance for proposed system is evaluated for the parameters  bit error rate (BER) and Q factor .The constellation diagrams, and bit error rate (BER) of the recei...

Abstract OFDM (Orthogonal Frequency Division Multiplexing) is an excellent technology that will almost certainly play a large role in next generation wireless communication systems. However, in OFDM, no frequency diversity is exploited to improve BER performance. Today’s OFDM systems attempt to overcome this limitation by application of channel coding and interleaving, which requires a reductio...

A method called offset modulation (OM-OFDM) is proposed to control the peak-to-average power ratio (PAPR) of an OFDM signal. The authors demonstrate the significant modulation, structural and performance differences between an OM-OFDM and CE-OFDM method. The OM-OFDM method in addition is able to accurately control the PAPR of a transmission for a targeted BER, which is currently not possible wi...

Due to the increase of users the efficient usage of spectrum plays an important role in digital terrestrial television networks. In digital video broadcasting, local and global content are transmitted by single frequency network and multifrequency network respectively. Multifrequency network support transmission of global content and it consumes large spectrum. Similarly local content are well ...

Low power consumption and high data rate are the most important requirements for the communication system. Especially, very low power consumption modulation method is required for the short range communication systems such as the medical implantable communication devices or capsule endoscope, and so on. For the higher data rate, we like to combine the OFDM system into the QAPM since the OFDM sy...

In this modern wireless technology Multicarrier communication is one of the more suitable and reliable communication technique. Orthogonal Frequency Division Multiplexing (OFDM) is used as modulation technique in multicarrier communication. The present paper gives an overview of OFDM and the various Channel Estimation techniques used in OFDM. The results implemented in MATLAB gives the performa...

In this paper we propose an energy efficient OFDM transmission scheme. Two CPM (continuous phase modulation) schemes are introduced to OFDM, keeping in view the constant envelope and continuous phase changing nature of CPM modulation. Energy efficiency of the proposed scheme is investigated by simulating PAPR (peak to average power ratio) and is compared with the conventional OFDM scheme. The i...