Analysis of Phase Noise in a Hybrid Photonic/Millimetre-Wave System for Single and Multi-Carrier Radio Applications

Abstract

The future evolution of wireless networks, throughout the 5G era and beyond, will require the expansion and augmentation of millimetre-wave systems for both terrestrial and satellite communications. Photonic technologies offer a cost efficient and high bandwidth platform for millimetre-wave carrier generation and distribution, but can introduce high levels of phase noise through optical heterodyning, which is highly problematic for mobile signal waveforms. In this work, a detailed analytical model of a hybrid photonic/mm-wave system is developed and discussed. Through careful system design, the system is found to support both 5G compatible multi-carrier (OFDM) and single carrier (APSK) modulation at 60 GHz. APSK is found to offer higher tolerance mm-wave phase noise compared to OFDM, ultimately easing optical linewidth restrictions to ∼30 kHz. The model is extended to include a novel millimetre wave phase noise cancelling receiver, which is shown to significantly alleviate these restrictions even further—enabling phase noise free mm-wave operation for optical linewidths up to ∼2 MHz. Detailed analysis and discussion of this extended system lead to the establishment of a theoretical relationship between the mm-wave receiver design and the achievable system performance in terms of error vector magnitude (EVM). Excellent matching of the predicted theoretical with simulated performances is shown.

Flexible Optical and Millimeter-Wave Analog-RoF Transmission with a Silicon-based Integrated Dual Laser Module

“…The composite mmwave signal (carrier and data signal are amplified and then transmitted over a wireless link of 1 -2 m using a set of 20 dB gain directional horn antennae. The transmission of the mm-wave data signal alongside a phase noise correlated carrier, enables phase noise and frequency offset cancellation using an analog electrical PNC receiver structure which is described in detail in [5,17] . Mixing of the mm-wave carrier and data sideband terms at the PNC stage produces a clean IF OFDM signal which is then captured by a real time oscilloscope (RTO) at 50 GSa/s before offline processing consisting of synchronization, channel estimation and equalisation and EVM measurement was performed.…”

“…optical access networks) for mm-wave generation and distribution -a concept known as 'convergence' [2,3] . Indeed, our previous works have explored how a pair of optical carriers with a mm-wave frequency difference may be distributed over an analog radio-over-fiber (A-RoF) fronthaul link from a central office (CO) to a remote radio head (RRH) for heterodyne detection; directly producing a mm-wave mobile signal after the photo-detection stage [4,5] . Although the A-RoF (i.e.…”

Wavelength & mm-Wave Flexible Converged Optical Fronthaul With a Low Noise Si-Based Integrated Dual Laser Source

“…1 -provides reduced cost and complexity of RUs at the antenna sites [20], [26], helping to facilitate network scaling. The authors' recent works have demonstrated how this RAN architecture can be deployed in conjunction with centralized, flexible optical heterodyne mm-wave generation and A-RoF transmission; serving to increase system spectral efficiency and flexibility while further reducing RU complexity [5], [6]. These aspects are particularly advantageous for future C-RAN deployments considering the ultra-dense deployment of the antenna sites required for high-frequency wireless systems [7].…”

“…More recently, research has focused on how these methods may be integrated with existing optical infrastructure (e.g., optical access networks) for mm-wave generation and distribution -a concept known as 'convergence' [3], [4]. Indeed, our previous works have explored how a pair of optical carriers with a mm-wave frequency difference may be distributed over an A-RoF fronthaul link from a central office (CO) consisting of a central unit (CU) and distributed unit (DU) to a remote radio unit (RU) for heterodyne detection; directly producing a mm-wave mobile signal after the photo-detection stage [5], [6]. Although the A-RoF transmission approach introduces stringent linearity, phase noise and frequency offset requirements [5], it holds a distinct advantage over current digital approaches in terms of both spectral efficiency and the potential for network scaling [7].…”

Optical phase-locked loop phase noise in 5G mm-wave OFDM ARoF systems

“…In the latter, OFDM properties are combined with numerical algorithms to recover data even with high carrier phase noise. By mitigating the impact of optical coherence these algorithms are a path to relax the constraints on sources purity [28], allowing a widespread use of cheap and common laser sources in OFDM mm-wave transmissions. In particular this can be used to make OPLLs a better candidate for the generation of remote-fed optical LOs and it represents a very promising and viable method for the new 5G ARoF fronthaul.…”