5G New Radio (NR) has been a great success story since its introduction. It offers high reliability, low communication latency, flexibility, and efficiency that further enable 5G networks to be used for mission critical applications. Currently, there are specialized networks serving industry verticals that would benefit from the NR properties. Key use cases include communications for critical infrastructure such as railways, public safety, and smart energy and infrastructure. These networks often use dedicated spectrum allocations that are narrower than the original minimum operating bandwidth of NR. In this paper, we describe how new flexibility is being introduced into the NR design to allow operation with bandwidths between about 3 and 5 MHz. As a use case study, we focus on railway communications, and study the co-existence of the Global System for Mobile Communications–Railway (GSM-R) and Future Railway Mobile Communication System (FRMCS) based on NR during the decade-long migration period. We discuss the changes required for the NR control channels and signaling and study the effect of the changes on the system performance.

Industry 4.0 is forming the manufacturing industry towards more agile and networked operations enriched by exploitation of new technology. Manufacturing is also one of the key verticals defined by the 5G Infrastructure Public Private Partnership (5G PPP) aimed at digital transformation in industrial communication. In this paper, we will present the current status of the VTT’s (VTT Technical Research Centre of Finland Ltd) Industry X Smart Manufacturing Testbed, which enables Finnish industrial companies to test and experiment new production methods and technologies in an industrial-like environment. The testbed utilizes technologies varying from robotics to 5G and beyond connectivity, and from international data spaces (IDS) to extended forms of reality (AR, VR, MR) and digital twins. The testbed is built in a hierarchical manner. Inter-connected factory level testbeds comprise of factory process level processes that are grouped into use case families. These processes include several proofs of concept demonstrators, which utilize different technologies available in the testbed. In this paper, three recent proof-of-cencepts (PoC) are briefly presented to illustrate the next-generation manufacturing possibilities using the latest communication technologies available.

This paper presents a proposal for dynamic spectrum management concept from a pan-European research operator perspective. Dynamic spectrum management is one of the key enablers for the 5G and beyond communications systems. Regulatory concepts for sharing the spectrum have been developed, and they have been adopted for implementation in the standardization. The prevailing methods are currently Licensed Shared Access (LSA) in the European Union (EU) and Citizens Broadband Radio Service (CBRS) in the United States (US). In the EU, however, the final decisions of the spectrum usage are done by the national regulatory authorities, and therefore it is seen that harmonized spectrum usage is not going to happen at European level in the near future. In this paper, we describe the approach taken in EuWireless to gain access to the spectrum resources dynamically for the research use. In the proposal, the information about the spectrum resources across the Europe are stored the central Spectrum Repository (SR). The local instances of EuW Spectrum Manager (SM), operating under the licences and regulations in different areas, handle the communication with the MNOs via standardized procedures such as LSA or CBRS.

The D2D-Relay mechanism, which integrates device-to- device (D2D) communications and relay technology, is promising in system performance improvement. This paper focuses on studying what kind of benefits the D2D-Relay mechanism could bring into a wireless communication system during the uplink transmission. To comprehensively analyze the system performance, we use a metric, which consists of the spectral efficiency (SE) and the energy efficiency (EE), as an indicator. With this criteria in mind, we theoretically describe the influence from users' preferences to the SE and the EE in detail. Noting that user pairing is an important part of this mechanism, we evaluate the performance of the D2D- Relay mechanism with three typical pairing algorithms based on different criteria. The simulation results conform to our derivations and reveal the performance gain brought by applying the D2D-Relay mechanism. In addition, with different configurations of the number of the users and their preferences to the SE and the EE, the most appropriate algorithm is suggested for the practical application.

This paper investigates the trade-off between throughput and energy consumption in heterogeneous networks with dual connectivity and backhaul delay. The problem of traffic splitting between the main eNB and secondary eNBs is formulated as a multi-objective optimization problem. Based on some observations, assumptions, and subsequent simplifications, two algorithms are devised. One targets throughput optimization (TO) by transmission delay minimization. The other one does energy savings (ES) by not transmitting on the main eNB depending on the delay allowance defined in the QoS criterion of the transmitted data. The main eNB is in control of the data transfer to the secondary eNB. Simulations show that the TO algorithm performs slightly better than an earlier published algorithm in which the secondary eNBs are in control of the data transfer from the main eNB. The ES algorithm does save energy at the expense of a larger transmission delay.

We consider full-duplex multi-hop forwarding in a Beyond 4G local area network. In the network, there is a high density of self-backhauling relay nodes that simultaneously act as access points towards the users, in addition to few nodes with wired backhaul. The access is framed and synchronized along the multi-hop flow, and the nodes apply time division duplexing. Interference cancelation as well as power optimization is performed within the multihop route. Simulations are carried out in a local area network consisting of multiple multi-floor buildings. The propagation channel is modelled using static pathloss, log-normal distributed random variable, or static pathloss with Rayleigh fading. The simulation results indicate that full-duplex relaying improves the network performance over half-duplex relaying, if self-interference channel attenuation is kept over 80 dB. The means of achieving tolerable self-interference levels in full-duplexing relays via physical design of the relay, and analog and digital interference cancellation are discussed.

We consider multi-hop forwarding in a Beyond 4G local area network, where in addition to nodes with wired backhaul, there is a high density of self-backhauling relay nodes acting simultaneously as access points towards users. The nodes apply Time Division Duplexing, access is framed and synchronized along a multi-hop flow, and there is a corresponding reuse factor for active hops along a multihop route. Interference cancelation, as well as power and resource optimization, is performed within along a route. Simulations are performed in a local area network consisting of multiple multi-floor buildings. Multi-hop self-backhauling is found to significantly improve the coverage of high data rates in the system.

Reliable spectrum sensing is one of the key technologies for enabling cognitive communications. In this paper, spectrum sensing based on Welch periodogram is applied to a femtocell scenario where cognitive femto base station (FBS) is located in the same frequency band as the surrounding macrocell and neighboring femtocells. Parameters for the femtocell simulations are selected based on 3G Partnership Project (3GPP) contributions to tie this work to on-going femtocell standardization work. Different interference scenarios are also discussed. Spectrum sensing based on Welch periodogram is presented, and two scenarios including a user equipment (UE) located indoor and outdoor are selected for further study. The results, given as receiver operation characteristic (ROC) curves, clarify the practical regions inside of which spectrum sensing is capable of providing reliable results for sensing the presence of the MUE.

Reliable spectrum sensing is one of the key technologies for enabling spectrum coexistence. In this paper, co operative spectrum sensing based on the Welch periodogram is studied in frequency selective fading environment for quadrature phase shift keying (QPSK) and orthogonal frequency division multiplexing (OFDM) signals. Parameter selection for sensing OFDM signal is discussed, and near-optimal values for frequency averaging for QPSK and OFDM signals are derived. The results, given as receiver operating characteristic (ROC) curves, indicate that the frequency-selective fading degrades the performance of the sensing. This could be compensated by co-operation of several sensing nodes. Both analytical and simulation results indicate that best performance of spectrum sensing is achieved with different combining rules in the case of signal passing through additive white Gaussian noise (AWGN) or fading channels.

In this paper, a novel solution to dynamically control the resources of a WiMAX system is proposed. The presented solution is aligned with the NGN trends, as well as with the WiMAX Forum guidelines and architecture. The interaction with the WiMAX systems is performed through SNMP, supporting the standardized IEEE 802.16 f MIB. Furthermore, the paper defines an horizontal abstraction layer, hiding the WiMAX equipments specific functionalities from the network control plane, thus providing robustness and vendor independency. In order to verify the performance of the proposed framework, a WiMAX testbed has been installed, and a set of measurements have been made, showing that the proposed system ensures a quick resource allocation, even for a large number of simultaneous resource reservation requests.

In environmental monitoring, wirelessly connected sensors form local networks and collect data, which are sent to a central repository for further analysis and permanent storage. In this paper we empirically evaluate the use of fixed WiMAX to backhaul data from an environmental monitoring application. We find that aggregating sensor readings is crucial for taking full advantage of the WiMAX backhaul. We consider application-layer aggregation for scenarios where sensor communication is programmable or at least configurable. For scenarios where sensors cannot be modified, we consider network-layer aggregation using a performance enhancing proxy. Finally, we consider the case where application- and network-layer aggregation are combined. Our results show that without aggregation, goodput is only a small fraction of the maximum achieved in our testbed. Furthermore, we examine the effect of different modulation schemes on performance and quantify in practice the number of wireless sensor nodes that could be served with different modulation and data aggregation combinations.

The standard IEEE 802.16 was originally conceived for targeting local and metropolitan area networks, for relatively small link distances. However, the significant deployment of novel wireless-based applications as well as the availability of advanced transmission techniques has suggested a possible extension of the standard-based systems to mountainous and isolated areas. From the propagation point of view, those demanding scenarios result in to non-line-of-sight, long delay spread, and very rich scattering radio environments. Nowadays, no channel models proposed in the literature are suitable for modeling 3.5 GHz transmission in such demanding scenarios. In this paper we propose a possible solution by analyzing and modifying the IST-WINNER model. According to the simulations, the novel channel model characterizes the strong peaks due to the reflection from a mountain and the interfering paths due to near scatterers. The combination of these paths creates a long delay spread that can be fatal for OFDM-based systems. Finally, in order to show the impact of the challenging scenario on the system performance, we present the results related to a system-level simulation using beamforming/MIMO techniques.

Accurate channel estimates are needed in space-time coded OFDM systems for decoding purposes. In this paper, a novel channel tracking algorithm based on space-time coded training and information symbols is presented. The algorithm takes advantage of the orthogonality properties of the space-time block codes and it is therefore capable of providing channel estimates without performance degradation due to estimation errors from adjacent channels. The algorithm is tested via Monte Carlo computer simulations using both slowly Rayleigh fading channels and time-invariant frequency selective channels and Alamouti space-time block coding. Computer simulations also show that this simple algorithm outperforms LMS-based approach without additional complexity.