Utilizing the abundant bandwidth in millimeter wave frequency bands is an interesting option to enable wireless communication services with challenging latency and reliability requirements for factory automation. Nevertheless, millimeter wave bands have less favorable propagation properties compared to lower bands, which impacts the coverage negatively. In this paper, we show that millimeter wave bands can fulfill extreme latency and reliability requirements with much higher system capacity than mid-band frequencies by means of beamforming, large antenna arrays, and network densification. This makes millimeter wave bands suitable for providing ultra-reliable low-latency communication services for factory automation. However, we find that small beam misalignments due to channel state information error can degrade the system capacity substantially.

Digital substations (DS) became a large evolutionary advancement for electrical substations with introduction of IEC 61850 communication protocol due to minimized digital and control infrastructure involved. However, maintenance cost and simplicity can further be improved if wired communication between the control room and switchyard is complemented or substituted with a wireless solution. Wireless connectivity can bring benefits to both brown- and greenfield installations, to avoid cumbersome and expensive cable trenching or be used as a redundancy solution. Ultra-reliable low-latency communication (URLLC) technology developed in 5G networks promises support in this field. This paper presents performance results for 4G and 5G wireless systems enabling communication between switch yard and control room in digital substations. Evaluations of a 4G LTE Rel. 13 system was performed by measurements in lab environment and the performance of a 5G new radio (NR) network at the substation coexisting with surrounding macro network is done with system level simulations. Results of the tests and evaluations demonstrate the limitations of 4G LTE Rel. 13 connectivity, as well as capabilities to fulfill the communication needs in substation case using 5G NR system.

The tactile internet will enable a new range of capabilities to enable immersive remote operations and interactions with a physical world. Tactile internet use cases span over many fields, from remote operation of industrial applications in, e.g., hazardous environments, via remote-controlled driving in a fully automated intelligent transport system, to remote surgery where the unique expert skills can be delivered to different locations in the world. Fifth-generation (5G) communication will play a fundamental part in this tactile internet vision, as it will provide necessary capabilities for the demanding communication needs in terms of reliability and low latency, for operators or teleoperated systems that are connected wirelessly. This paper provides an overview of tactile internet services and haptic interactions and communication. The 5G functionality for ultrareliable and low-latency services is described in depth and it is shown how 5G new radio (NR) and the evolved long-term evolution (LTE) radio interface can achieve guaranteed low-latency wireless transmission. The costs for providing reliable and low-latency wireless transmission in terms of reduced spectral efficiency and coverage are discussed. The 5G system architecture with a software-based network design based on a distributed cloud platform is presented. It is shown how the 5G network is configured for tactile internet services via multidomain orchestration.

5G is expected to support mission-critical ultra- reliable low-latency communication services in addition to enhanced mobile broadband applications. Ultra-reliable low-latency communication refers to wireless communications where successful data transmission can be assured within extremely low latency bounds and with high reliability. In this paper, we investigate the network coverage and capacity of ultra-reliable low-latency communication services that are provided over realistic cellular deployments using 3.5GHz and 800MHz bands with NR and LTE-Advanced radio interface technologies (3GPP Release 15) and Vodafone's existing macro grid in London. An assessment of the existing fixed network core performance is done, which is connected to the simulations of the performance of the radio access network to get the end-to-end service perspective. It is shown that both NR and LTE-Advanced can fulfill 5ms latency target with 99.999% reliability. However, only NR can support the even stricter 1ms latency target, thanks to its flexible numerology. Furthermore, the ultra- reliable low- latency communication service capacity is shown to be very low for the LTE carrier compared to that of the NR, due to the scarcity of bandwidth resources at the LTE band, and the larger antenna arrays of NR. The evaluations include ray-tracing propagation modeling utilizing a 3D digital map of the coverage area together with site positions provided by Vodafone.

Shortening the transmit time interval (TTI) has been considered in 3GPP LTE as an effective way for latency reduction. In this paper, we discuss the physical layer design aspects for uplink data transmissions with short TTI (sTTI). Here, an sTTI consists of one or a few SC-FDMA symbols, and its time duration is less than 1 ms. Different methods of demodulation reference signals (DMRS) design, DMRS sharing and DMRS multiplexing, are introduced to reduce the reference signal overhead when shortening the TTI length. Our link level simulation results show that both methods can efficiently reduce the DMRS overhead, and thereby improve the system throughput. Moreover, we show that due to better channel estimates, a shorter TTI, e.g., 2-symbol TTI, is more robust towards high Doppler scenarios. In contrast, for a 7-symbol TTI, which is 0.5 ms, more than one reference symbols can be inserted in order to improve the channel estimates in high Doppler scenarios. Finally, a discussion is given on how several short TTIs can be multiplexed into the frame format used for LTE.

By allowing simultaneous transmissions in neighbouring cells the spectral reuse and the overall throughput of a WLAN system can be increased. We have investigated the impact of varying the clear channel assessment threshold (CCAT) in different network deployments defined by IEEE 802.11ax Task Group, and we show the potential of 4 different algorithms. By increasing the CCAT value from today's legacy value of -82 dBm to -62 dBm, an increase of up to 23% in the mean user throughput is observed. Further improvements are observed by using more advanced algorithms such as dynamic sensitivity control (DSC). The performance is also compared to those of reuse 1 systems and systems with uplink-downlink separation.