A New Approach for Wireless Cellular Network Design

Wise arrangement of antennas is critical in wireless cellular systems for both reductions of co-channel interference (CCI) and increase the quality of service (QoS). In this paper, a novel architecture for antenna arrangement in CDMA wireless cellular systems is presented. In this architecture that we called Microzone, every cell is divided into three (or more) zones and information transmission in downlink channel is done by an antenna which is placed at the outer region of the related zone. Also, the transmitting signal by the mobile station (MS) in uplink channel is received by all the antennas of the related cell. Analytical calculations of the received signal to noise ratio (SIR) and outage probability for both microzone and used architectures show that proposed architecture has better performance in compared with the used architecture. Also, simulation results confirm lower outage probability in uplink channel for microzone architecture.

A Novel All-Optical Sensor Design Based on a Tunable Resonant Nanocavity in Photonic Crystal Microstructure Applicable in MEMS Accelerometers

In view of the large scientific and technical interest in the microelectromechanical system(MEMS)accelerometer sensor and the limitations of capacitive,resistive piezo,and piezoelectric methods,we focus on the measurement of the seismic mass displacement using a novel design of the all-optical sensor(AOS).The proposed AOS consists of two waveguides and a ring resonator in a two-dimensional rod-based photonic crystal(PhC)microstructure,and a holder which connects the central rod of a nanocavity to a proof mass.The photonic band structure of the AOS is calculated with the plane-wave expansion approach for TE and TM polarization modes,and the light wave propagation inside the sensor is analyzed by solving MaxwelFs equations using the finite-difference time-domain method.The results of our simulations demonstrate that the fundamental PhC has a free spectral range of about 730 nm covering the optical communication wavelength-bands.Simulations also show that the AOS has the resonant peak of 0.8 at 1.644μm,quality factor of 3288,full width at half maximum of 0.5nm,and figure of merit of 0.97.Furthermore,for the maximum 200nm nanocavity displacements in the x-or y-direction,the resonant wavelengths shift to 1.618μm and 1.547μm,respectively.We also calculate all characteristics of the nanocavity displacement in positive and negative directions of the jc-axis and y-axis.The small area of 104.35μm^(2)and short propagation time of the AOS make it an interesting sensor for various applications,especially in the vehicle navigation systems and aviation safety tools.