A Tunable Wireless Multicarrier Communication Employing Multiple Vector Modulation With 4QAM-OFDM on a Single Optical Carrier

Guang Li,Jianqing Li,Zhihua Lin,Xuguang Huang

doi:10.1109/access.2019.2943905

Abstract

A wireless communication system with tunable multicarrier based on optical comb is investigated in this paper. This study is an initial attempt to modulate multiple vector microwave signals with different frequency on a single optical carrier, and then transmit these optical signals over a standard single-mode fiber with the length of 30 km, and finally demodulate them at the remote unit via a photoelectric direct detector without strict frequency-phase synchronization. Such a design can decrease the equipment cost and improve the frequency efficiency. In the transmitting terminal unit (TTU), a flat multi-wavelength optical comb with 13 channels and the channel space of 10 GHz can be obtained by the microwave photonics technology. In the radio-frequency remote unit (RRU), we can not only obtain the wireless carriers with the frequency of 5 GHz, 10 GHz, 35 GHz, 40 GHz, 65 GHz, 70 GHz, 95 GHz, and 100 GHz via a photoelectric direct detector that are used for wireless transmission between the mobile terminal and the radio-frequency remote unit, but also get three optical sources that can be utilized for the uplink. Meanwhile, the wireless access rate can reach up to 20 Gbps between RRU and MT. In this arrangement, compared with a conventional microwave photonics link, the optical spectrum utilization efficiency and transmission rate not only can be doubled, but also the maintenance cost of RRU can be reduced greatly.

Highlights

Microwave photonics link (MPL) transmission, radio over fiber or microwave transmission on an optical fiber has been considered as an excellent solution for the future wireless communications due to the low transmission loss, large bandwidth, low cost, anti-interference, low power consumption, and simple architecture of the remote radio-frequency unit [1]–[6]
In order to transmit a radio frequency (RF) vector signals on the optical fiber, the RF vector signals are normally generated by digital signal processing (DSP) and up-conversion in the electrical domain and, encoded by coherent modulation via an optoelectronic modulator in the optical domain [16], [18], [21]
In view of the six conclusions above, we propose a communication system with tunable wireless multicarrier based on multi-wavelength optical comb, double vector modulation on a single optical carrier, single sideband pulse shaping, and photoelectric direct detection

Summary

INTRODUCTION

Microwave photonics link (MPL) transmission, radio over fiber or microwave transmission on an optical fiber has been considered as an excellent solution for the future wireless communications due to the low transmission loss, large bandwidth, low cost, anti-interference, low power consumption, and simple architecture of the remote radio-frequency unit [1]–[6]. In order to recover the two electric vector signals, an optical source is employed, which is as a local oscillator (LO) used for the coherent detection In their scheme, the optical spectrum efficiency of the MPL has been doubled. In view of the six conclusions above, we propose a communication system with tunable wireless multicarrier based on multi-wavelength optical comb, double vector modulation on a single optical carrier, single sideband pulse shaping, and photoelectric direct detection. Such a design can decrease the equipment cost, improve the frequency efficiency and increase transmission rate.

SYSTEM ARCHITECTURE

NUMBERICAL SIMULATION

ANALYSIS AND VERIFICATION

VIII. CONCLUSION