Nokia (Canada)

We review four years of studies on various applications of coherent point-to-multipoint transceivers enabled by digital subcarrier multiplexing. We highlight the benefits of this approach to realize truly sustainable, scalable, and flexible optical networks. ©2025 The Author(s)

We review coherent DSP and transceiver technologies evolved over the past two decades and provide a brief outlook. The coherent landscape is expanding to shorter-reach applications, with emerging requirements of low power and latency.

We quantify the benefit from Hollow Core Fibers (HCF) versus common SSMF regarding the total capacity in modern WDM transparent backbone networks for various network sizes, various fiber losses in dB/km and various span lengths

Monolithic silicon sub-bandgap avalanche photodetectors are fabricated using the introduction of lattice defects to silicon waveguides through silicon ion implantation and annealing. The devices are characterized using light at a wavelength of 1550 nm. Through control of implantation dose we create a low-absorption device with 0.4 dB (5.4 dB/cm) excess optical absorption, and a high-absorption device with 3.2 dB (42 dB/cm) excess optical absorption. The low-frequency unity-gain bias point, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M</i> = 1, is approximately 12 V for both devices. Increasing reverse bias results in electrical gain such that <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M</i> = 35 at 32 V for the high-absorption device, with associated responsivity of 13 A/W for coupled optical power ranging from −20 dBm to −5 dBm. The electrical bandwidth of this device peaks at 10 GHz for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M</i> = 14 and decreases to 6 GHz for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M</i> = 35. The <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RC</i> limited bandwidth of an unimplanted, control device is measured to be 26 GHz. The gain-bandwidth product of the high-absorption device is 230 GHz. Measurement of the excess noise factor provides an effective <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> -value of 0.1, consistent with the gain-bandwidth product. Primary carriers in the avalanche process are predominatly electrons, with a carrier ionization threshold of ∼ 0.6eV, indicating for the first time in this device type that both the light detection and avalanche process are mediated by the deep-levels.

Augmented and Virtual Reality promises have yet to be met, it remains inhibited by an average user experience. Limits in local processing (headset/handset), form factors and display/optical limitations have kept the technology from reaching its full potential. 5G and Cloud-based processing offers the potential to improve performance, comfort/ergonomics, mobility and QoE barriers. Our research demonstrates a methodology for assessing AR/VR QoE performance on mobile networks and how 5G and cloud-based processing create a better user experience, accelerating the growth of this nascent market. QoE models are proposed for AR/VR which define the key quality indicators (KQIs) for each AR/VR application and we correlate the KQIs performance to network KPIs. The study demonstrates how typical LTE KPIs are insufficient to deliver an immersive QoE for AR/VR. Finally, we quantify the increase in QoE with 5G and edge cloud based on the expected KPI performance improvements. The proposed AR/VR QOE models are evaluated in the context of the enhanced network performance with 5G and Edge Cloud deployment.

Coexistence with wireless-fidelity (Wi-Fi) is a key aspect for licensed assisted access (LAA) to succeed. The main coexistence mechanism between both technologies is listen before talk (LBT), whereby radio frequency energy is sensed over a short period of time and compared to an energy detection (ED) threshold. If the sensed energy is below the ED threshold, a node is then allowed to transmit. Otherwise, it backs off. Given the default Wi-Fi and LAA ED thresholds, and the lack of virtual carrier sensing at the LAA side, coexistence problems may raise at below such ED thresholds. In order to address this issue, we propose a practical and easy implementable adaptive ED threshold algorithm, which can dynamically tune the ED threshold at the Wi-Fi and LAA nodes. Simulations results in an enterprise scenario show that the Wi-Fi performance can be significantly enhanced, while moderately impacting LAA performance.

Notification is a service that addresses devices and users with messages to be processed immediately or at a specific time. Notification is important for delivering emergency, warning, and other timely messages. In this article extensions to include notification service in the data transport system called IP DataCast used in the DVB-H mobile television standard are presented. The architecture of IPDC in DVB-H is first overviewed, and the notification service elements complementing it are described. Next, the notification protocols and message formats are defined, and the system operation is explained. The presented notification system is now part of the new IPDC over DVB-H standard.

We present an efficient algorithm for continuous image recognition and feature descriptor tracking in video which operates by reducing the search space of possible interest points inside of the scale space image pyramid. Instead of performing tracking in 2D images, we search and match candidate features in local neighborhoods inside the 3D image pyramid without computing their feature descriptors. The candidates are further validated by fitting to a motion model. The resulting tracked interest points are more repeatable and resilient to noise, and descriptor computation becomes much more efficient because only those areas of the image pyramid that contain features are searched. We demonstrate our method on real-time object recognition and label augmentation running on a mobile device.