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Radio-over-fibre for generation and transmission 32-tupling frequency optical millimeter wave with polarization modulators

Chen Xinqiao, Dai Siyuan, Liu Xiaorui, Chen Xu, Li Zhihan

Optica Applicata

2024

Vol. 54, nr 1

51--67

A novel structure to generate 32-tupling frequency millimeter-wave (MMW) signal using polarization modulators (PolM) is proposed. The ±16th order sidebands are generated by the 16th order sidebands generator which is mainly constructed by six PolMs and beat in a photodetector for generating the 32-tupling frequency MMW. The optical sideband suppression ratio (OSSR) of the generated ±16th order sidebands are 29.89 and 29.7 dB from theoretical analysis and simulation. The radio frequency (RF) spurious suppression ratio (RFSSR) of the obtained 32-tupling frequency MMW are 23.88 and 23.32 dB from theoretical analysis and simulation. A radio over fiber (ROF) system to transmit the generated 32-tupling frequency MMW is built. In the center station, the +16th order sideband from the ±16th order sideband generator is filtered out by a filter, after the downlink data is modulated on it. It is recombined with –16th order sideband and transmitted to the based station over fiber. In the based station, a part of –16th order sideband is reflected by a fiber Bragg grating (FBG), and the uplink data is modulated on it and transmitted to the center station over fiber. The signal emerging from the FBG is injected into the photodetector and the 32-tupling frequency MMW with downlink data is generated. The simulation results show that for the transmission fiber length 30 km, the bit-error-rate (BER) is less than 10–9, the power cost of the uplink and downlink is less than 0.44 and 0.5 dB, respectively.

Design of Hybrid Precoder for mm-Wave MIMO System Based on Generalized Triangular Decomposition Method

Thurpati Sammaiah, Muthuchidambaranathan P.

International Journal of Electronics and Telecommunications

2022

Vol. 68. No. 3

519--525

Hybrid precoding techniques are lately involved a lot of interest for millimeter-wave (mmWave) massive MIMO systems is due to the cost and power consumption advantages they provide. However, existing hybrid precoding based on the singular value decomposition (SVD) necessitates a difficult bit allocation to fit the varying signal-to-noise ratios (SNRs) of altered sub-channels. In this paper, we propose a generalized triangular decomposition (GTD)-based hybrid precoding to avoid the complicated bit allocation. The development of analog and digital precoders is the reason for the high level of design complexity in analog precoder architecture, which is based on the OMP algorithm, is very non-convex, and so has a high level of complexity. As a result, we suggest using the GTD method to construct hybrid precoding for mmWave mMIMO systems. Simulated studies as various system configurations are used to examine the proposed design. In addition, the archived findings are compared to a hybrid precoding approach in the classic OMP algorithm. The proposed Matrix Decomposition’s simulation results of signal-to-noise ratio vs spectral efficiencies.