This paper describes the design, fabrication, and measurement of a multiple U-shaped slot antenna for Hiper-LAN. The prototype consists of a U-shaped slot and two inverted U-shaped slot. To obtain sufficient bandwidth, a foam layer is inserted between the ground plane and substrate. A measured bandwidth of approximately 7.6% (VSWR 1.5) and gain of 2.9-5.3 dBi are obtained. The experimental far-field patterns are shown to be stable across the pass band, with the 3 dB beam width in azimuth and elevation at 50and 62, respectively.

In this study, a multiple U-shaped slot microstrip patch antenna for application to the 5 GHz band is designed and fabricated. To obtain sufficient bandwidth in the operating band, foam is inserted between the substrate and ground plane, the type of form is styrofoam, the coaxial probe source is used, and the position of the probe shift is adjusted from the center to the left. The measured result (5.02-5.955 GHz) of the fabricated antenna satisfies the conditions of VSWR < 2.0 in 5 GHz band (5.15-5.35 GHz, 5.47-5.725 GHz, 5.725-5.825 GHz), gain of 3.88-9.28 dBi, and broad radiation pattern.

In this paper, we propose an enhanced signal to interference ratio (SIR) measurement algorithm and evaluate the performance of the proposed algorithm in a WCDMA forward link receiver with closed-loop fast transmit power control. The proposed algorithm reduces measured SIR offset by using a pilot channel (CPICH) to compensate for the attenuated signal power in fading channel environment. The proposed SIR measurement algorithm outperforms conventional SIR measurement algorithm with regard to mean SIR values and jitter, especially in high speed mobile channel environment. Also, performance results with closed loop power control show that the proposed algorithm has better performance than the conventional algorithm.

Network life time and hence device life time is one of the fundamental metrics in wireless body area networks (WBAN). To prolong it, especially those of implanted sensors, each node must conserve its energy as much as possible. While a variety of wake-up/sleep mechanisms have been proposed, the wake-up radio potentially serves as a vehicle to introduce vulnerabilities and attacks to WBAN, eventually resulting in its malfunctions. In this paper, we propose a novel secure wake-up scheme, in which a wake-up authentication code (WAC) is employed to ensure that a BAN Node (BN) is woken up by the correct BAN Network Controller (BNC) rather than unintended users or malicious attackers. The scheme is thus particularly implemented by a two-radio architecture. We show that our scheme provides higher security while consuming less energy than the existing schemes.

Different quality of service (QoS) requirements must be guaranteed in multimedia code division multiple access (CDMA) mobile communication system to support various applications such as voice, video, file transfer, e-mail, and Internet access. In this paper, we analyze the system in a mixed-traffic environment consisting of voice, stream data, and packet data where preemptive priority is granted to delay-intolerant voice service and a buffer is offered to delay-tolerant stream data services. In the case of best-effort packet data service, the probability of access control by transmission permission is applied to obtain throughput improvement. To analyze the multimedia CDMA mobile communication system, we built a two-dimensional Markov chain model on high-priority voice and stream data services, and then performed numerical analyses in conjunction with packet data services based on a residual capacity equation. We investigate the performance of an integrated voice/stream-data/packet-data CDMA mobile system with the finite buffer size of stream data in terms of voice service blocking probability, average stream data service delay, average packet data service delay, and throughput.

An effective transmitter power control method is indispensable in combating the near-far problem and minimizing the effect of interference on the system capacity. This paper investigates the power control problem for the uplink direct sequence-code division multiple access (DS-CDMA) system. In recent works on power control problem, power levels are assumed to take on any positive real value. However, in practical systems, power levels are discrete. This paper therefore proposes a power control algorithm over a discrete set of power levels in which each base station locally optimizes the power set of all users in its own cell. Also, we investigate its convergence and power consumption properties. Simulation results indicate that the proposed power control algorithm converges faster and provides an improved performance.

In this paper, a meander-type microstrip patch antenna for application in 5 GHz-band is designed and fabricated. To obtain enough bandwidth in VSWR<2, the foam is inserted between substrate and ground plane, the coaxial probe source is used. The measured result of fabricated antenna is obtained 1 GHz (17.5%) of bandwidth in VSWR<2, the gain of 7.3-9.5 dBi and unidirectional pattern.

Due to the ultra low power spectral desity of the ultra-wide band (UWB), narrow band interference (NBI) with high-level emission power will degrade the accuracy of UWB ranging system. We propose a novel waveform to suppress the accuracy degradation by NBI with a given frequency. In addition, we compare the ranging error ratio (RER) of the proposed scheme with the traditional one with Gaussian monocycle in this letter.