2 <formula formulatype="inline"><tex Notation="TeX">$\times$</tex></formula> 2 MIMO OFDM-RoF System Employing LMS-Based Equalizer With I/Q Imbalance Compensation at 60 GHz

Abstract

Multiple-input-multiple-output (MIMO) technology is a promising method to increase spectral efficiency in wireless communications. In this paper, a 60-GHz orthogonal frequency-division multiplexing radio over fiber (OFDM-RoF) system employing 2 Â 2 MIMO wireless technology is demonstrated. With the proposed equalizer employing least mean squares (LMS) algorithm, MIMO channel mixing and I/Q-mismatch can be compensated simultaneously. 16-QAM and 32-QAM OFDM signal transmissions under forward error correction (FEC) threshold (1 Â 10 À3 ) are demonstrated. A data rate of 76.3 Gb/s can be achieved with a bit-loading algorithm over 25-km fiber transmission and 3.5-m wireless transmission.

Nonlinear coded nonuniform superposition QAM by trellis-coding for MISO system in visible light communication

“…A joint least mean square (LMS) (MIMO LMS) software equalizer [20] is utilized to compensate inter-symbol interference (ISI) and inter-channel interference (ICI) by deducting the product of the symbol value and the tap weights from the received signal. Because it is only concerned with the input, it also suits MISO systems.…”

Optical millimeter wave signal generation with frequency 16-tupling using cascaded MZMs and no optical filtering for radio over fiber system

“…Hence optical MM-Wave generation and RoF transmission methods have been proposed. Though there are several methods of optical MM-Wave generation techniques, external modulation based optical frequency multiplication techniques have gained much attention due to its higher modulation bandwidth, stability and flexibility [4][5][6][7]. Several optical frequency upconversion/multiplication techniques have been demonstrated with different frequency multiplication such as four, six, eight, ten and twelve [8][9][10][11][12][13][14][15][16].…”

60-GHz optical/wireless MIMO system integrated with optical subcarrier multiplexing and 2x2 wireless communication

“…Then, two MIMO signals are downconverted to 5.5 GHz by using a 55-GHz local oscillator and two balanced mixers and then received by an oscilloscope at a sampling rate of 40 Gsample/s. [6]. The QAM signals are de-mapped to binary data streams and the BERs are measured according to error count, as shown in the inset (ii) of Fig.…”