Experimental Investigation of Zadoff-Chu Matrix Precoding for Visible Light Communication System with OFDM Modulation

Abstract

Light-emitting diode-(LED-) based visible light communication (VLC) has become a potential candidate for next generation high-speed indoor wireless communication. Due to the limited modulation bandwidth of the LED, orthogonal frequency division multiplexing (OFDM) modulation is particularly preferred in the VLC system to overcome the ISI, which suffers from the high peak-to-average power ratio (PAPR) and leads to severe performance loss. In this paper, we propose and experimentally demonstrate a novel Zadoff-Chu matrix (ZCM) precoding scheme, which can not only reduce the PAPR, but also provide uniform signal-to-noise ratio (SNR) profile. The theoretical analysis and simulation show that the proposed scheme achieves better PAPR performance compared with the traditional precoding schemes. The experimental demonstration further validates the bit error rate (BER) performance improvement, where the measured BERs are all below the 7% pre-forward error correction (pre-FEC) limit of 3.8 × 10 −3 when the transmitted data rate is 50 Mb/s.

OFDM joint communication–radar with leaky‐wave antennas

“…The OFDM preamble—a Zadoff–Chu (ZC) sequence—provides the channel estimation for communication links. It is a constant amplitude chirp [6 ], i.e. a linear FMCW sweep.…”

“…One key feature of the reported communication–radar is the utilisation of a ZC sequence for channel estimation in the preamble of an OFDM frame. The ZC preamble further enables to lower the peak‐to‐average‐power‐ratio of OFDM–QAM signals, which improves one of their main disadvantages [6 ]. In principle, the ZC sequence comprises a constant amplitude‐frequency sweep, which is exploited to estimate the frequency selective behaviour of a (wireless) communication channel.…”

“…4. The other angular user positions yielded BERs of 2.4 × 10 –3 at −20°, 3.78 × 10 –4 at −10° and 2.3 × 10 –3 at 0°, all well below the 3.8 × 10 –3 forward error correction (FEC) limit [6 ]. Therefore, five simultaneous transmissions of 4 Gbit/s each were achieved.…”

Analysis on Wavelet Family based Channel Estimation for MIMO-OFDM System

“…In OFDM the signal is modulated with specific frequency and bandwidth for which it uses the spaced subcarriers. OFDM techniques [1] [2] [3] are generally used in Audio video and Digital television broadcast, wireless networks, Wi-Fi (standards like 802.11a, 802.11ac etc). The receiver will receives the overall signal, which can be again demodulated to retrieve original data's.…”