No abstract

In this paper, a two efficient Planar Inverted-F Antenna (PIFA) system for dual-band functionality on fourth-generation (4G) band (2.5-2.7 GHz) and future fifth-generation (5G) band (3.4-3.8 GHz) is presented. During the optimization process, in order to obtain an efficient system, particular attention has been paid to the antenna system efficiency as well as the isolation between the antennas. Thus, the influence of the antenna slot design used to achieve a dual-band behavior on the antenna efficiency has been particularly studied. Moreover, the antenna positions on the Printed Circuit Board (PCB) have been chosen thanks to the use of characteristic mode analysis to obtain high isolation levels in both bands. The final system is optimized for Multiple Input Multiple Output Half Duplex (MIMO HD) 4G communications and Tx/Rx Full-Duplex (FD) 5G communications. A prototype with 140 mm × 70 mm ground plane was simulated, fabricated and measured. A high isolation level between the two ports of the PIFA elements, better than 35 dB in 5G band and 20 dB in 4G band in simulation and measurement that were done in free space, is obtained. Additionally, the most important diversity metrics are computed to evaluate the potential of this two-antenna system for diversity applications.INDEX TERMS Full-duplex (FD), half duplex (HD), isolation, multiple input multiple output (MIMO), planar inverted-F antenna (PIFA), multi-band antenna system.

No abstract

Abstract-The wide deployment of Wi-Fi networks empowers the implementation of numerous applications such as Wi-Fi positioning, Location Based Services (LBS), wireless intrusion detection and real-time tracking. Many techniques are used to estimate Wi-Fi client position. Some of them are based on the Time or Angle of Arrival (ToA or AoA), while others use signal power measurements and fingerprinting. All these techniques require the reception of multiple wireless signals to provide enough data for solving the localization problem. In this paper, we describe the major techniques used for positioning in Wi-Fi networks. Real experiments are done to compare the accuracy of methods that use signal power measurement and Received Signal Strength Indication (RSSI) fingerprinting to estimate client position. Moreover, we investigate a fingerprinting method constrained by distance information to improve positioning accuracy. Localization techniques are more accurate when the estimated client positions are closer to the real geographical positions. Accuracy improvements increase user satisfaction, and make the localization services more robust and efficient.

No abstract