Mixed Reality (MR) has launched from science fiction but its entrance in reality can reshape our society. By combining the physical and virtual worlds, it provides novel ways of immersive interactions and experiences and by these means enables a new generation of applications. The most exciting and challenging ones support collaborative, multi-user operation in large geographical scale, require real-time environment comprehension and high visual fidelity. The success or failure is definitely impacted by the capabilities and performance limits of edge cloud platforms and 5G/6G networks providing the offloading features for CPU/GPU intensive MR functions. In addition, the desired quality of user experience calls for further mechanisms at the application level hiding the consequences of varying network characteristics. In this paper, we propose a novel edge cloud based architecture for future remote-rendered MR applications supporting low-latency immersive interactions. Our contribution is threefold. First, the system architecture is presented focusing on the remote rendering, 3D simulation and environment detection control loops. Second, we highlight the main features of our proof-of-concept prototype and our dedicated application, namely the Mixed Reality version of a Rocket League inspired game. Third, the concepts are validated via experiments in a Beyond 5G infrastructure where we analyze the operation and latency characteristics of the overall system. In addition, the quality of the user experience is also evaluated via real-life experiments conducted as part of a student competition. The results show that the latency and jitter characteristics of the most sensitive render loop can be managed efficiently together by a network-level control (slice priorities) and an application-level (dynamic jitter buffer) mechanism.

This paper presents a comprehensive characterization of kinaesthetic data traffic and associated performance trade-offs in multimodal bilateral haptic teleoperation over 5G networks. Utilizing two widely adopted haptic devices interacting with virtual environments, precise telemetry on motion and force was obtained across various interaction types and virtual object properties. The study investigates the effects of network resource allocation within a 5G standalone private network by employing three predefined network slicing profiles prioritizing haptic, audio, or video traffic. Performance evaluations were conducted using Quality of Service (QoS) metrics, from which potential implications for Quality of Experience (QoE) were subsequently inferred. The results show the interplay between traffic patterns and resource allocation, identifying configurations that ensure high-fidelity haptic feedback while maintaining acceptable audiovisual quality. These insights lay the groundwork for future research on adaptive network management strategies for haptic-enabled teleoperation systems.

Immersive technologies such as Extended Reality (XR) and holography are experiencing a significant growth [1] [2]. The main use case of these technologies are usually gaming and entertainment. However, there are fields in which they can be beneficial if they are used for human-to-human communications, such as education, in which real benefits are already being discovered [3]. Holography is one of the most interesting immersive technologies, as it does not require to wear any device to experience a 3D effect. This study shows a preliminary, exploratory research with holographic cabins communicating over a private 5G network for education. Early results show that, even if it cannot be proven with statistical methods yet, users think they have great potential for remote education. Out of 12 subjects, 91% of users preferred an holographic lesson over traditional videoconferencing methods (Microsoft Teams) and 75% of users think that it was easier for them to learn with holograms versus traditional videoconferencing methods.

This study proposes an adaptive positioning algorithm for UAVs in real urban 5G networks, leveraging existing cellular infrastructure with a practical approach. Unlike previous studies that rely on idealized scenarios, this work addresses the challenges of operating in real-world environments, where networks are designed for cellular coverage rather than positioning. The algorithm combines Received Signal Power (PRx) with the Dilution of Precision (DOP) from base stations to optimize dynamic station selection, improving system geometry and reducing estimation errors. To predict the UAV’s future position and calculate DOP in real-time, Kalman filters with Interacting Multiple Models (IMM), based on Constant Acceleration (CA) and Constant Velocity (CV) models, are employed. Additionally, a least squares approach with Taylor expansion, complemented by Tikhonov regularization, mitigates errors arising from ill-conditioned matrices. The methodology is applied to a predefined clustering of base stations in the city of Valencia (Spain), where each cluster is analyzed and optimized. The impact of the handover threshold on system accuracy is studied, proposing an inter-cluster handover scheme based on centroids. Experimental results obtained in a real urban environment demonstrate that the hybrid model significantly improves accuracy in handover zones compared to approaches relying solely on PRx.

Haptic teleoperation systems mark a critical breakthrough in remote manipulation technologies, delivering immersive user experiences through precise control and tactile feedback. This paper aims to explore the interplay between Quality of Service (QoS) network metrics, such as latency, jitter, and packet loss, and Quality of Experience (QoE) features, including immersion, control, and engagement. This investigation is conducted through a combination of objective measurements and subjective evaluations over a private Fifth Generation Standalone (5G SA) network. In addition, it aims to realize the extent to which transport-layer protocols operating over IP, such as TCP and UDP, as well as environmental factors like indoor and outdoor settings, influence system performance.Results confirm the well-established trade-off between reliability and latency in transport protocols, with TCP offering higher reliability in controlled indoor environments, and UDP exhibiting better responsiveness in dynamic outdoor scenarios. While these findings align with existing knowledge, their empirical validation in the context of immersive haptic applications over a private 5G SA network reinforces their relevance. In addition, QoE metrics were found to be linked to QoS indicators, highlighting the importance of balancing speed, stability, and reliability. These findings provide valuable insights towards designing adaptive teleoperation systems capable of dynamically optimizing performance under diverse conditions.

Research efforts to incorporate multicast and broadcast transmission into the cellular network architecture are gaining momentum, particularly for multimedia streaming applications. Layered division multiplexing (LDM), a form of nonorthogonal multiple access (NOMA), can potentially improve unicast throughput and broadcast coverage with respect to traditional orthogonal frequency division multiplexing (FDM) or time division multiplexing (TDM), by simultaneously using the same frequency and time resources for multiple unicast or broadcast transmissions. In this paper, the performance of LDM-based unicast and broadcast transmission in a cellular network is studied by assuming a single frequency network (SFN) operation for the broadcast layer, while allowing for arbitrarily clustered cooperation for the transmission of unicast data streams. Beamforming and power allocation between unicast and broadcast layers, and hence the so-called injection level in the LDM literature, are optimized with the aim of minimizing the sum-power under constraints on the user-specific unicast rates and on the common broadcast rate. The problem is tackled by means of successive convex approximation (SCA) techniques, as well as through the calculation of performance upper bounds by means of semidefinite relaxation (SDR). Numerical results are provided to compare the orthogonal and non-orthogonal multiplexing of broadcast and unicast traffic.

The bitstream structure of layered media formats such as scalable video coding (SVC) or multiview video coding (MVC) opens up new opportunities for their distribution in Mobile TV services. Features like graceful degradation or the support of the 3-D experience in a backwards-compatible way are enabled. The reason is that parts of the media stream are more important than others with each part itself providing a useful media representation. Typically, the decoding of some parts of the bitstream is only possible, if the corresponding more important parts are correctly received. Hence, unequal error protection (UEP) can be applied protecting important parts of the bitstream more strongly than others. Mobile broadcast systems typically apply forward error correction (FEC) on upper layers to cope with transmission errors, which the physical layer FEC cannot correct. Today's FEC solutions are optimized to transmit single layer video. The exploitation of the dependencies in layered media codecs for UEP using FEC is the subject of this paper. The presented scheme, which is called layer-aware FEC (LA-FEC), incorporates the dependencies of the layered video codec into the FEC code construction. A combinatorial analysis is derived to show the potential theoretical gain in terms of FEC decoding probability and video quality. Furthermore, the implementation of LA-FEC as an extension of the Raptor FEC and the related signaling are described. The performance of layer-aware Raptor code with SVC is shown by experimental results in a DVB-H environment showing significant improvements achieved by LA-FEC.

H.264 Scalable Video Coding (SVC) is an extension to the Advanced Video Coding (AVC) H.264 standard which provides efficient scalability functionalities on top of the high coding efficiency of H.264/AVC. SVC allows for temporal, spatial, and quality scalability of the output video stream, encoding the video information into an H.264/AVC base layer and a series of enhancement layers which incrementally improve the quality, increase screen resolution and/or frame rate. SVC is particularly suited for mobile TV reception, since the received video quality is adaptable to variable reception conditions and heterogeneous receiver capabilities. However, mobile TV Digital Video Broadcasting (DVB) standards such as DVB-H and DVB-SH were designed prior to the introduction of SVC, and therefore the underlying transmission protocols are not optimized for scalable video delivery. In this overview paper, we review recently proposed solutions for SVC stream adaptation on the underlying DVB-H/SH protocols, and point out novel technical solutions that are currently under consideration for the next generation mobile broadcasting standard DVB-NGH.

This paper investigates how Scalable Video Coding (SVC) can benefit from different Forward Error Correction (FEC) and transmission schemes in mobile broadcast systems. Simulation are performed in DVB-H (Digital Video Broadcasting - Handheld) systems. In DVB-H, a differentiation in robustness for the different SVC layers can be achieved at the link layer using intra-burst MPE-FEC (multi-Protocol Encapsulation FEC). The paper evaluates the gain that can be achieved with the MPE-FEC using equal (EEP) and unequal error protection (UEP), and the performance improvements of an SVC layer-aware FEC (LA-FEC) approach that can be implemented in DVB-H either at the link layer with MPE-iFEC (inter-burst MPE-FEC) or at the application layer with AL-FEC. LA-FEC improves the SVC base layer robustness generating parity information across existing dependencies within the SVC video coding structure. Laboratory measurement results using a TU6 channel model show that the performance of an SVC service in DVB-H can be significantly increased by a proper link layer FEC scheme. It is shown that using SVC in combination with LA-FEC and a proper transmission scheduling does not only give a better performance in terms of PSNR and amount of video outages compared to a single layer service at the same service bit rate, but also gives an additional lower quality layer which can be used for applications like conditional access.

This paper investigates the performance of time interleaving in DVB-T2 in the context of mobile reception. By means of time interleaving it is possible to provide time diversity and improve the robustness of the transmitted information in mobile environments. DVB-T2 implements a highly flexible time interleaving that allows different trade-offs in terms of time diversity, latency and power saving. DVB-T2 also includes the possibility to particularize the transmission parameters on a service basis by means of multiple physical layer pipes. This way, it is possible to accommodate different use cases: fixed, portable and mobile, in the same frequency channel. This paper evaluates the time interleaving capabilities of DVB-T2 by means of physical layer simulations. The paper also proposes and evaluates a configuration that has been optimized for handheld reception.

This article investigates efficient broadcast delivery of file download (filecasting) services in hybrid broadcast and cellular systems formed by a DVB-H network and an evolved 3G+ cellular network with HSDPA and MBMS capabilities. In particular, we investigate the delivery cost savings that can be achieved using HSDPA and MBMS to repair errors of the initial DVB-H broadcast transmission. In a realistic scenario, there may be users that experience significantly worse DVB-H reception conditions than the majority, such that it may be more efficient to serve them through the cellular network. To enable an easy and efficient implementation of the repair mechanisms in the hybrid DVB-H/3G+ system, we adopt application layer forward error correction (AL-FEC) with Raptor coding. With AL-FEC specific packets are not required to be retransmitted, and repair transmissions consist of additional repair packets that can be used for all users. Hence, repair data can be seamlessly delivered with unicast HSDPA, multicast MBMS, and broadcast DVB-H transmissions. Furthermore, AL-FEC provides a multiburst protection of the DVB-H transmission to exploit the time diversity of the mobile broadcast channel.

Abstract People travelling in public transportation vehicles are foreseen to be a relevant use case of future Digital Video Broadcast—Handhelds (DVB‐H) systems. However, it is also one of the critical user cases, since, besides the vehicle penetration loss, the received signal quality is strongly affected by the high mobility of the users, which is accompanied by temporary shadowing and fast fading. On the other hand, mobility can be also beneficial thanks to the bursty character of DVB‐H transmissions, as additional repair data can be sent in the time intervals between original service bursts in order to hide the coverage discontinuities from the users' perception. In this way, users which miss the original transmission have more chances to receive the information correctly. By managing the amount of repair data the network operator can trade system capacity and network latency for improved vehicular user satisfaction in a DVB‐H network with imperfect coverage of the service area (as perceived by the vehicular users). To illustrate the potential of this approach, we evaluate the mentioned trade‐off in a DVB‐H system dimensioned for pedestrian outdoor users, for both streaming and filecasting services. To enable an easy and efficient implementation of the repair mechanisms, we adopt application layer forward error correction (FEC), as it can provide a multi‐burst protection of the transmission. Copyright © 2008 John Wiley & Sons, Ltd.

This article studies the performance of the Sliding RS Encoding (SRSE) in the transmission of streaming services in DVB-H (Digital Video Broadcasting - Transmission System for Handheld Terminals) networks. The SRSE forms part of a set of specifications called MPE-iFEC which has been recently defined in the DVB-SH (Digital Video Broadcasting - Satellite Services to Handheld Devices) standard and is fully compatible with the link layer of DVB-H. MPE-iFEC is capable of encoding information related to different datagram bursts in a jointly manner in order to counteract the long signal blockages expected in satellite reception. This is what is usually referred to as Multi-Burst Encoding (MBE) and provides a protection that extends across several time sliced bursts. MBE can also improve the reception in terrestrial networks such as DVB-H, which relay in the use of MPE-FEC (Multi Protocol Encapsulation - Forward Error Correction) for link layer protection. The SRSE employs the same Reed Solomon (RS) algorithm used in MPE-FEC and a sliding encoding mechanism in order to perform MBE. This paper evaluates the improvements that the use of SRSE can achieve over the legacy MPE-FEC using vehicular urban field measurements in a DVB-H single frequency network. The effect of the different parameters that regulate the operation of the SRSE will be evaluated and the best configurations for its use in DVB-H will be highlighted.

Reliable filecasting to vehicular users in wireless broadcast networks is a very challenging task, as an error-free transmission of the files is required. Reliability can be achieved by means of forward error correction (FEC) and post-delivery file repair mechanisms. In this paper, we describe and compare the standardized FEC schemes in DVB-H (digital video broadcast-handheld) at the link and application layer, and evaluate their performance for file delivery to vehicular users. We show that by using application layer FEC it is possible to efficiently correct the errors appeared due to temporarily shadowing and fast fading, by taking advantage of the time and space diversity introduced by the bursty character of DVB-H transmissions and terminal mobility. Our results may constitute a valuable guide for operators when dimensioning their network capacity and service bandwidths, especially in the situations when vehicular users represent a large part of the customer base.

This paper addresses the problem of efficient planning DVB-H networks assuming that the existing broadcasting and cellular infrastructure can be used in the network deployment. The planning objective consists in deciding which existing cellular sites should be used jointly with the broadcasting towers in a minimum cost deployment. A multi-objective genetic algorithm has been utilized to seek minimum cost network configurations as a function of the area coverage level. We investigate the achievable cost savings offered by a hybrid infrastructure compared to using only the existing broadcasting towers and the cellular sites separately

In this paper the impact of the soft handover micro diversity gain on the UMTS system performance is investigated. First, by means of link layer simulations the micro diversity gain is measured in terms of reduction of the average Eb/N0requirement. After modelling this effect, by some system level simulations we show the high influence of this usually neglected gain in the overall performance of UMTS, demonstrating that in downlink soft handover improves not only the quality of service but also the overall system capacity

This paper evaluates the capability of application layer - forward error correction (AL-FEC) with Raptor coding for improving the reception of DVB-H streaming services for mobile terminals. In particular, we exploit the benefits coming from the spatial diversity introduced by terminals' mobility. We consider the introduction of an additional burst with parity information transmitted several seconds after the original burst. In this way, mobile terminals which are not able to successfully decode the original burst will have an extra chance to recover the missing information by synchronizing to the additional burst. Simulation results show how it is possible to trade system capacity and streaming delay for increased user satisfaction. A comparison with alternative techniques as using MPE-FEC (multi protocol encapsulation - FEC), reducing the modulation and coding rate (MCR) order at the physical layer, and performing burst retransmissions is also included.

This paper presents a comprehensive approach to solve the problem of joint dynamic resource allocation (JDRA) in heterogeneous wireless networks using a Hopfield neural network (HNN). A generic formulation for packet services with delay constraints is proposed to decide the optimal bit rate and radio access technology (RAT) allocation. Some illustrative simulations results in a basic scenario are presented to evaluate performance of the proposed algorithm.

This article investigates the scalability of DVB-H deployment on existing wireless infrastructure for digital broadcasting and cellular networks. Three deployment strategies are investigated: when only the broadcasting and the cellular infrastructure are used separately, and the case when both can be used jointly. The outcomes show that, in general, the investment needed for increasing the service capacity by switching to higher order modulation, or for increasing the coverage level over a given service area, lead to a higher annualized cost per Mb/s