Turbo Coded OFDM with Large Number of Subcarriers

Abstract

Wireless communication systems have greatly advanced during the last years. A significant contributor in these systems’ performance has been Orthogonal Frequency Division Multiplexing (OFDM). Since its invention, it is considered to be a technological leap. This leap in splitting an information stream in multiple frequency carriers has been adapted by various scientists working on the development of wireless systems. Moreover, as OFDM presented excellent tolerance of channel fading and noise signals, the evolvement in terms of speed and reliability was consequent, because only a small stream of information is lost due to noise effects. OFDM along with the knowledge that Turbo codes is another excellent scheme of reducing BER, has triggered us to expand our research. So, we experimented in simulation level not only in joining OFDM with Turbo Codes but even in finding a better Turbo scheme compared to a typical PCCC, SCCC and a Convolutional encoder with Viterbi decoder. As the last goal has already been accomplished, in this paper is presented the new OFDM system consisted of our Turbo scheme. The analysis of the previous system took into consideration the effects of an AWGN channel. Also, this noise analysis was conducted using a simulation platform with specific attributes such as transmitting and receiving fixed number of subcarriers (2048 carriers after IFFT block) while using different types of convolutional concatenated codes, such as PCCC (Parallel), SCCC (Serial) and the new PCCC scheme. The results clearly show not only the improvement in the BER performance of the Turbo Coded OFDM systems (compared to others consisted of Viterbi decoders) but the overall superiority of the proposed design

Constant envelope OFDM RadCom fusion system

“…To make radar processing easier, the time-domain CE-OFDM multi-carrier transmitted signal can be expressed as [7][8][9].…”

“…For multicarrier RadCom waveforms, an additional multiple-access technique is required for multiple-user communication operation [7], and dedicated frequency-domain processing techniques can be exploited to improve the performance of the radar application. In terms of broadband continuous waveform, orthogonal frequency division multiplexing (OFDM) is the key technology of Long-Term Evolution (LTE) and its performance can be promoted by encoding, e.g., the turbo code [8,9].…”

Reduced Ecological Footprints of Modern Facilities Introducing the Implementation of Advanced Wireless Technologies, and Human Resources’ Benefits

“…• (REFFPP06): Advanced network decisions and predictions [41], control algorithms and concatenated coding (for communication purposes with a typical of 20% lower power dissipation) [42] [43] [44] should be used for the optimal management of energy systems producing the lowest possible carbon footprint [45].…”

A Haar Wavelet Decision Feedback Channel Estimation Method in OFDM Systems

“…But when the signal passes through the wireless fading channel, it will be disturbed by the additive white Gaussian noise (AWGN) which affects the quality of signal transmission and the performance of the system. Some papers [7,8] use Turbo coding with code rate of 1/3 and 1/2 respectively at the transmitter in OFDM system to suppress the effect of noise in wireless channel. It can obtain good performance in bit error rate (BER).…”