Experimental Research of Modulation-Coding Schemes Influence on Size of the DRM Digital Radio Broadcasting Service Area in the VHF Band. Part 2

The article presents the results of measurements of the parameters of the digital radio broadcasting DRM signal quality in the experimental zone of St. Petersburg in order to determine the influence of the transmission modes laid down in the DRM standard on the size of the service area.

Experimental Research of Modulation-Coding Schemes Influence on Size of the DRM Digital Radio Broadcasting Service Area in the VHF Band. Part 1

The article presents the results of measurements of the parameters of the digital radio broadcasting DRM signal quality in the experimental zone of St. Petersburg in order to determine the influence of the transmission modes laid down in the DRM standard on the size of the service area.

Reconfigurable Intelligent Surfaces for Doppler Effect and Multipath Fading Mitigation

Owing to the envisioned new use-cases, such as immersive virtual reality and high-fidelity mobile hologram, and their potential challenging new requirements for future wireless networks, extensive research has already started on 6G and beyond wireless technologies. Despite the fact that several modern physical layer solutions have been introduced in the past decade, a level of saturation has been reached in terms of the available spectrum and adapted modulation/coding solutions, which accordingly limits the maximum capacity and reliability. Within this respective, reconfigurable intelligent surface (RIS)-empowered communication appears as a potential candidate to overcome the inherent drawbacks of legacy wireless systems. The core idea of RIS-assisted communication is the transformation of the random and uncontrollable wireless propagation environment into a reconfigurable communication system entity that plays an active role in conveying information and improving system performance. In this paper, the well-known multipath fading phenomenon is revisited in mobile wireless communication systems, and novel and unique solutions are introduced from the perspective of RISs. The feasibility of eliminating or mitigating the multipath fading effect stemming from the movement of mobile receivers is also investigated by utilizing RISs. It is shown that rapid fluctuations in the received signal strength due to the Doppler effect can be effectively reduced by using real-time tunable RISs. It is also proven that for a hypothetical propagation environment where all reflectors are coated with RISs, the multipath fading effect can be totally eliminated. Furthermore, we show that for more general propagation environments with several interacting objects, even a few real-time tunable RISs can remarkably reduce the Doppler spread and the deep fades in the received signal.

Advanced modulation coding schemes for an optical transceiver systems–based OWC communication channel model

This paper examines advanced modulation coding schemes for an optical transceiver systems–based optical wireless communication (OWC) channel model. These modulation techniquesinclude On-Off keying and return to zero (RZ)/non–return to zero (NRZ) coding. The signal power level against time and frequency spectral variations are measured. The max. Q factor and min. bit error rate (BER) are estimated and clarified for each modulation code scheme by using an optisystem simulation model. Transmission bit rates of up to 40 Gb/s can be achieved for possible distances up to 500 km with acceptable Q factor. The received power and max. Q factor are measured and clarified with OWC distance variations. The On-Off keying modulation code scheme resulted in better performance than the other modulation code schemes did.

Cellular Communication Propagation at Drone around Building Environment with Single Knife Edge at 10 GHz

The drone communication systems used a cellular network for controlling a drone from a long distance. That communication propagations between drone and base station were analyzed. The drone moved at the track around building environment. That environment used variations in building height. The communication propagation around building environment caused diffraction mechanism. Single knife edge method is used for that diffraction mechanism. The frequency of communication used 10 GHz. That frequency was influenced by atmospheric attenuation. This research was using some variations such as height of drone track location, transmitter power, and AMC (Adaptive Modulation Coding). MCS (Modulation Coding Scheme) was used AMC such as QPSK, 16 QAM, and 64 QAM. Some result was obtained at this research consist of LOS and NLOS distance, SNR, MCS probability, and percentage of drone coverage. NLOS propagation was caused by building height. The SNR value become increase when higher at drone position, such as drone was moving at 20 meters with height of flying drone 80 m and transmitter power 30 dBm obtained SNR 38.21 dBm. That SNR is affected AMC, so a higher SNR value increases AMC. The drone’s coverage 100%, with a height of flying drone 80 meters and transmitter power of 30 dBm. That condition showed more increasing coverage percentage than 64.8% for height of flying drone 20 meters and transmitter power 30 dBm. That result showed that more drone height increased of coverage percentage, probability modulation, and SNR value.

Smart Soil Monitoring System for Smart Agriculture

Accurate and timely information is crucial to optimize resources. Sensors determine clay, organic matter, moisture, and nutrients of soil. Sensors at various locations are connected using different technologies. Its data will be automatically reported to cloud without any internet connection. Sensors broadcast data to local base stations (LBS) at different ranges of distances using WiFi, LPWAN, LoRa, Bluetooth, etc., and then to central base station (CBS), which is far away. Modulation, coding techniques, and line of sight keeps signal intact. Data from CBS goes to cloud for analysis, visualization, and trend analysis. This helps farmers to get frequent and real-time data without actual need of physical presence. It reduces manpower, water usage, and other costs of agriculture and has positive environmental impact. Integration with other data like weather forecasts gives more precise information. Convergence of technologies, sensors, cloud, automation, etc. without human interaction contributes to IoT.

Measurement-Based Investigations of the NB-IoT Uplink Performance at Boundary Propagation Conditions

This paper presents experimental results of investigations on narrowband Internet of Things (NB-IoT) uplink channel performance under extreme pathloss conditions, approaching the boundary maximum coupling loss (MCL) defined for cellular IoT systems. The system performance was systematically tested against several modulation coding schemes (MCSs) and a set of repetition numbers (Nrep) in electromagnetically isolated facilities, guaranteeing proper environment separation from external factors that usually affect measurements in less controlled setups. Some of the major takeaways include the following observations. Firstly, every increase in the number of repetitions by a factor of four caused the performance to improve by about 3 dB. Secondly, the switchover between extreme MCSs (i.e., MCS0 and MCS10) caused the performance to shift by about 6 dB. Thirdly, chipsets from different vendors performed similarly at small values of Nrep, but tended to diverge for larger numbers of repetitions. These findings may serve as benchmark figures for other theoretical and simulation-based studies by demonstrating performance in response to Nrep and MCSs for a vast scope of their values. Future investigations will concern the impact of multipath channels, typical in real-life deployment scenarios.

Experimental Study of a Signal Modulation Method to Improve eLORAN Data Channel Communications

There are mainly two types of data modulation methods used for enhanced LOng-RAnge Navigation (eLORAN) systems: pulse position modulation (PPM) and supernumerary interpulse modulation (SIM). The typical application for PPM is tri-state PPM (3S-PPM), also known as Eurofix. The typical application for SIM is ninth pulse modulation. Both of these methods are phase modulation methods. Phase modulation coding, a very mature technology, is used at present. To achieve a better demodulation success rate of eLORAN digital modulation signals at longer distances, a method of using the transmitting station duplex mode to transmit a digital modulation pulse group after LORAN-C transmitting a pulse group is proposed to realize modulation pulse on–off modulation. In this method, a broadcasting experiment was performed on the BPL (The call sign of eLORAN time service system in China) broadcaster station. After monitoring, a good receiving demodulation effect was initially obtained.