Urban Area Propagation Path Loss Reduction by Dynamic Differential Evolution Algorithm

[[abstract]]In the wireless outdoor communication, the buildings in modern cities to make the outdoor communication more difficult. In this paper, we propose the shooting and bouncing ray/image (SBR/Image) method to compute the path loss for outdoor environments in the commercial area of New Taipei. Three types of antenna arrays such as L shape, Y shape, and circular shape arrays are considered. Moreover, dynamic differential evolution algorithm (DDE) is employed to optimize the excitation voltages and phases for these antenna arrays to reduce the path loss and compare with the genetic algorithm (GA). The GA and DDE optimization is applied to a high order nonlinear optimization problem. By the obtained antenna patterns, we can find the route with the lowest path loss; meanwhile, transmission power using this route in the base station can be reduced. Numerical results show that the performance in reduction of path loss. The DDE algorithm outperforms the GA for proposed antenna arrays. The investigated results can improve design of outdoor communication system.[[conferencetype]]國際[[conferencedate]]20140423~20140425[[conferencelocation]]Taipei, Taiwa

Path Loss Reduction for Multiusers by Different Antenna Arrays

[[abstract]]In this paper, we use the shooting and bouncing ray/image (SBR/Image)[1]-[5] method to compute the path loss for different outdoor environments. Three types of antenna arrays such as L shape, Y shape, and Circular shape arrays are used in the base station and their corresponding path loss on several routes in the outdoor environment are calculated[6]-[8]. Moreover, the genetic algorithm (GA) and Dynamic Differential Evolution (DDE) are employed to optimize the excitation voltages and phases for antenna arrays to form proper antenna patterns[9], [10]. The particle swarm optimization algorithm has better optimization result than genetic algorithm in NLOS case. For antenna arrays Y shape has better optimization result in NLOS case.[[conferencetype]]國際[[conferencedate]]20140714~20140718[[conferencelocation]]Arusha, Tanzani

Channel Modeling and Characteristics for 6G Wireless Communications

[EN] Channel models are vital for theoretical analysis, performance evaluation, and system deployment of the communication systems between the transmitter and receivers. For sixth-generation (6G) wireless networks, channel modeling and characteristics analysis should combine different technologies and disciplines, such as high-mobil-ity, multiple mobilities, the uncertainty of motion trajectory, and the non-stationary nature of time/frequency/space domains. In this article, we begin with an overview of the salient characteristics in the modeling of 6G wireless channels. Then, we discuss the advancement of channel modeling and characteristics analysis for next-generation communication systems. Finally, we outline the research challenges of channel models and characteristics in 6G wireless communications.This research was supported by the National Key R&D Program of China under grant 2018YFB1801101; the National Nature Science Foundation of China (No. 61771248 and 61971167); the Jiangsu Province Research Scheme of Nature Science for Higher Education Institution (No. 14KJA510001); and the Open Research Fund of the National Mobile Communications Research Laboratory, Southeast University (No. 2020D14).Jiang, H.; Mukherjee, M.; Zhou, J.; Lloret, J. (2021). Channel Modeling and Characteristics for 6G Wireless Communications. IEEE Network. 35(1):296-303. https://doi.org/10.1109/MNET.011.200034829630335

Spectral Efficiency and Outage Performance Evaluation of Measured Vehicular Communication Radio Channels

[ES] Los sistemas cooperativos para entornos vehiculares tienen la capacidad de mejorar tanto la seguridad en carretera, como la gestión del tráfico. Tienen como base la norma del estándar de comunicaciones inalámbrico de red de área local (Wireless Local Area Network, WLAN) para el uso comunicaciones vehiculares (Vehicle-to-Vehicle/Infrastructure, V2I), denominada IEEE 802.11p, la cual se está desarrollando actualmente, y que dará lugar a la nueva tecnología de comunicaciones entre vehículos e infraestructura WAVE (Wireless Access in Vehicular Environments). Funcionando en el rango de frecuencias de 5.850 a 5.925 GHz, los sistemas WAVE adoptan la técnica de multiplexación OFDM (Orthogonal Frequency Division Multiplexing) y alcanzan tasas de transmisión de datos en el rango de 6 a 27 Mbps. El estudio del canal es clave para conocer el efecto de las condiciones de propagación reales sobre la transmisión. Habrá que tener en cuenta que en entornos de comunicaciones vehiculares se da la propagación con línea de visión directa (Line of Sight, LoS), por lo que a la hora de caracterizar el canal, habrá que considerar tanto el desvanecimiento Rayleigh como el desvanecimiento Ricean. Este estudio se hará a partir del procesado de la función de transferencia del canal obtenido para diferentes escenarios durante la campaña de medidas realizada en Lund, Suecia. en 2007 por la Universidad Técnica de Viena. El sistema radio utilizado considera múltiples antenas, es decir, el canal es Multiple-Input Multiple-Output (MIMO), dado que gracias a la diversidad consigue un mayor rendimiento. De cara a analizar el efecto de las condiciones de propagación sobre el rendimiento alcanzable, se caracterizará el canal mediante el Power Delay Profile (PDP) y el perfil de Path Loss. A continuación se estudiarán más en detalle los canales MIMO con desvanecimiento Ricean, cruciales para las comunicaciones Vehicle-to-Vehicle, (V2V). En estos canales hay una tasa de datos crítica (RCRIT) dependiente de una relación señal a ruido (Signal-to- Noise Ratio, SNR) bajo la cual la transmisión de datos con cero outage es posible, de manera que el canal se comporta como un canal con ruido aditivo gaussiano (Additive White Gaussian Noise, AWGN). Se analizará la tanto eficiencia espectral en términos de capacidad ergódica y como la probabilidad de outage del canal vehicular para diferentes valores de relación señal a ruido.[EN] Roadway-vehicle cooperative systems will lead to improve driving safety. These systems relay on a wireless local area network (WLAN) standard for automotive use, called IEEE 802.11p, which is under development in order to implement Wireless Access in Vehicular Environments (WAVE). Operating at 5.850¿5.925 GHz, WAVE systems adopt orthogonal frequency-division multiplexing (OFDM) and achieve data rates of 6¿27 Mbps. The development of efficient vehicle-to-vehicle (V2V) communications systems requires an understanding of the underlying radio propagation channels in order to analyze the real impact of real-world propagation conditions. Vehicular communication channels are non-stationary, because the conditions of the channel vary abruptly due to the speed of the vehicles. The studied wireless communication scenario is predominantly Line of Sight (LoS) propagation scenario, therefore Rayleigh fading and Ricean fading have to be considered for channel characterization. The reference data to be analyzed have been obtained from a channel sounding campaign carried out by the Vienna University of Technology in Lund, Sweden in 2007. The radio system used for this campaign is a multiple-input multiple-output (MIMO) system. Radio channel parameters such as the power delay profile and the path loss are going to be analyzed in order to study the impact of real-world propagation conditions. Reliability in Ricean MIMO channel is going to be more deeply characterized, as it is crucial for safety related V2V applications. In such channels, there is a SNR-dependent critical data rate (RCRIT) below which signaling with zero outage is possible, and hence the fading channel behaves like an AWGN channel. For the vehicular time variant channel spectral efficiency is going to be evaluated in terms of ergodic capacity and outage performance is also going to be studied by means of outage probability.Alonso Gómez, A. (2009). Spectral Efficiency and Outage Performance Evaluation of Measured Vehicular Communication Radio Channels. http://hdl.handle.net/10251/27442.Archivo delegad