Troels Kolding’s research while affiliated with Nokia and other places

Extended reality (XR) services form the basis of the metaverse, a fully immersive experience where users can interact with each other and digital objects in a three-dimensional real or imagined digital space. Past and ongoing standardization activities focus on enabling cellular networks to effectively support XR to ensure that the metaverse can be enabled everywhere. One enabling feature is application awareness (AA) within the service provisioning framework of 5G-Advanced. AA is extending the current quality of service (QoS) model to support a finer QoS granularity and add more detailed application information to improve radio resource management and eventually enhance users' immersive experience. Current and future AA innovations will enable cellular networks to improve system capacity and further optimize service provisioning to fit specific application needs. In this article, we present a comprehensive overview of AA for XR services in cellular networks and future research directions in that area.

Mechanisms for data recovery and packet reliability are essential components of the upcoming 6 th generation (6G) communication system. In this paper, we evaluate the interaction between a fast hybrid automatic repeat request (HARQ) scheme, present in the physical and medium access control layers, and a higher layer automatic repeat request (ARQ) scheme which may be present in the radio link control layer. Through extensive system-level simulations, we show that despite its higher complexity , a fast HARQ scheme yields > 66 % downlink average user throughput gains over simpler solutions without energy combining gains and orders of magnitude larger gains for users in challenging radio conditions. We present results for the design trade-off between HARQ and higher-layer data recovery mechanisms in the presence of realistic control and data channel errors, network delays, and transport protocols. We derive that, with a suitable design of 6G control and data channels reaching residual errors at the medium access control layer of 5 × 10 −5 or better, a higher layer data recovery mechanism can be disabled. We then derive design targets for 6G control channel design, as well as promising enhancements to 6G higher layer data recovery to extend support for latency-intolerant services.

Technology innovation for the sixth generation (6G) era should focus on improving quality of life by addressing societal needs, advancing human experience with the fusion of digital and physical worlds, and achieving a sustainable well-being. The 6G networks are expected to bring higher capacity and coverage combined with dependable real-time properties but must additionally be able to control the balance between quality of service (QoS) and quality of experience (QoE). QoS is the ability to offer measurable performance, reliable delivery to connect people and things. QoE is a way to measure the quality of a service as perceived by the end user, enabling a more customer/user-centric network design approach for end user services. To provide excellent QoS, accurate estimation of QoE and corrective measures to adapt QoS to maintain acceptable QoE from the end-user perspective will be needed. In this paper, we propose a linear weighted QoE model in terms of mean opinion score (MOS) and the ability to adapt QoS. We further validate our proposed QoE model with an impairment QoE model and analyze the individual model results with respect to the latency and bit rate metrics which are critical for our target use case; Virtual Reality (VR) gaming. We also propose to use the QoE model to enable adaptive QoS in the 6G radio access network (RAN), including dynamic learning of QoS metrics.

This paper presents a comprehensive analysis of fifth-generation (5G)-Advanced system-level performance, focusing on the coexistence of extended reality (XR) and enhanced mobile broadband (eMBB) traffic in the uplink direction of transmission. Two deployment scenarios of dense urban and indoor hotspot are considered. The study investigates the influence of uplink power control (UPC) parameters on the XR capacity and proposes strategies to manage eMBB inter-cell interference through traffic-specific UPC settings. By jointly optimizing UPC parameters for each traffic type, this research aims to minimize the eMBB throughput degradation while safeguarding the XR capacity. The findings reveal the impact of deployment scenarios on XR and eMBB capacity, and the trade-offs involved in the UPC optimization. These findings also offer valuable guidance to cellular operators for optimizing network configurations to accommodate emerging XR traffic alongside existing services.

In this paper, we address the joint performance of eXtended reality (XR) and best effort enhanced mobile broadband (eMBB) traffic for a 5G-Advanced system. Although XR users require stringent throughput and latency performance, operators do not lose significant additional network capacity when adding XR users to an eMBB dominated network. For instance, adding an XR service at 45 Mbps with 10 ms packet delay budget, yields close to a 45 Mbps drop in eMBB capacity. In an XR only network layer, we show how the capacity in number of supported XR users depends significantly on the rate but also the latency budget. We show also how the XR service capacity is significantly reduced in the mixed service setting as the system goes into full load and other-cell interference becomes significant. The presented results can be used by cellular service providers to assess their networks performance of XR traffic based on their current eMBB performance, or as input to dimensioning to be able to serve certain XR traffic loads.

Extended reality (XR) is an emerging technology that has gained significant attention in the context of fifth-generation (5G) and 5G-Advanced cellular networks and beyond. One of the less explored areas for practical XR service deployments is the study of its interaction with the existing traffic such as enhanced mobile broadband (eMBB). This study explores the performance of having both XR and eMBB users simultaneously in a multi-cell network for two different indoor and outdoor deployment scenarios. We show that the main limitation to maximizing XR capacity in the mixed scenario is inter-cell interference (ICI) generated by eMBB users. ICI from eMBB results in a loss of about 80% in XR capacity when an XR source data rate of 45 Mbps and a strict packet delay budget (PDB) of 10 ms is enforced. To mitigate this, we propose newradio resource management enhancements that apply restrictions on eMBB radio resource usage to balance between eMBB and XR simultaneous capacity. With the proposed enhancements, maximum XR capacity can be maintained for the case with an XR source data rate of 45 Mbps and a PDB of 20 ms while restricting eMBB throughput by about 50%. The impact on eMBB throughput performance from adding XR users depends on the XR PDB, deployment environment, and the eMBB radio resource usage restriction. The results demonstrate that the eMBB throughput declines with a factor of 1 to 4 of the XR sum rate.