This paper presents a novel 90 GHz band 16-quadrature amplitude modulation (16-QAM) orthogonal frequency-division multiplexing (OFDM) communication system. The system can deliver 6 Gbps through six channels with a bandwidth of 3 GHz. Each channel occupies 500 MHz and delivers 1 Gbps using 16-QAM OFDM. To implement the system, a low-noise amplifier and an RF up/down conversion fourthharmonically pumped mixer are implemented using a 0.1-μm gallium arsenide pseudomorphic high-electronmobility transistor process. A polarization-division duplex architecture is used for full-duplex communication. In a digital modem, OFDM with 256-point fast Fourier transform and (255, 239) Reed-Solomon forward error correction codecs are used. The modem can compensate for a carrier-frequency offset of up to 50 ppm and a symbol rate offset of up to 1 ppm. Experiment results show that the system can achieve a bit error rate of 10 -5 at a signal-to-noise ratio of about 19.8 dB.Keywords: W-band, PDD, OFDM, 10 Gigabit Ethernet, error correction code. Manuscript received Sept. 22, 2013; revised Feb. 10, 2014; accepted Feb. 13, 2014. Hyung Chul Park (corresponding author, hcpark@seoultech.ac.kr) is with the Department of Electronic and IT Media Engineering, Seoul National University of Science and Technology, Seoul, Rep. of Korea.
I. IntroductionAs high-speed wireless data services, such as 3G/4G mobile communications, IEEE 802.11ac/ad wireless LAN, and wired Gigabit Ethernet, are becoming more widespread, multi-gigabit Ethernet networks are needed. Compared to wired multigigabit Ethernet networks, wireless multi-gigabit Ethernet networks have the advantage of an easy installation and low construction cost. bandwidth of 3 GHz. In our previous work, we presented a single carrier 16-QAM based E-band (71 GHz to 76 GHz and 81 GHz to 86 GHz) wireless point-to-point broadband communication system [7]. In the previous system, the FDD scheme was used because the spectrum is divided into a lower band (71 GHz to 76 GHz) and an upper band (81 GHz to 86 GHz). However, since a bandwidth of 3 GHz (92 GHz to 95 GHz) is allocated in the 90 GHz band, the proposed system herein utilizes a polarization-division duplex (PDD) architecture to achieve both full-duplex communication and a multi-Gbps data rate. By using a PDD scheme, the spectral efficiency of full-duplex communication can be increased by two times compared to that of the FDD-or TDD-schemebased existing millimeter wave wireless communication. In addition, an OFDM technique and equalizer are used to reduce the effects of inter-symbol interference caused by multipath propagation.II. System Architecture and Function Blocks Figure 1 and Table 1 produces 1 Gbps of binary data. Figure 2 shows a detailed block diagram of the RF/IF transceiver. In the IF transmitter, the digital-to-analog converted signal is low-pass filtered by a seventh-order Butterworth filter with a cutoff frequency of 288 MHz. A passive type I/Q mixer is used for the up conversion, with a conversion loss of 7 dB.Six IF channel sig...
