Lway Faisal Abdulrazak

Co-channel and adjacent channel interference evaluation for IMT-Advanced coexistence with existing fixed systems

Due to spectrum scarcity and emerging various wireless applications, coexistence and sharing between IMT-advanced and fixed wireless access (FWA) systems becomes a recently critical issue. At WRC-07, ITU-R allocated 3400-3600 MHz band for the coming fourth generation (4G) or IMT-Advanced on a co-primary basis along with existing FWA systems. Therefore, coexistence and sharing requirements like separation distance and frequency separation coordination must be achieved in terms of both co-channel and adjacent channel frequencies. Co-sited the two base stations antennas and non co-sited coexistence of the two systems are analyzed (depending on interference to noise ratio of -6 dB as a standard coexistence criteria). The interference analysis models, adjacent channel interference ratio ACIR and spectral emission mask (SEM) are applied in the mentioned band to extract the additional isolation needed to protect adjacent channel interference. Finally, possible intersystem interference mitigation techniques are suggested.

Study HAPS interference power to noise level ratio of fixed services and related separation distance

This paper presents a methodology for determining the ratio of interference power to noise power at the input of a point-to-point receiver in the fixed service (FS) due to operation of a high altitude platform system (HAPS) station at any point visible to the FS receiver. Detailed description about the parameters, models, and possible I/N criteria that might be applied are mentioned in this research paper. The outcome methodology is described, applied and the results obtained with it are presented in a tables and graphs when HAPS platform transmitting to only one gateway station or aggregate interference when HAPS platform transmitting to a ten Gateway symmetrically.

Design and development of high-gain wideband circularly polarized patch antenna

New design of obtaining circular polarization (CP) radiation of a single-feed microstrip antenna is presented. The antenna substrate has an air-layer with thickness about 2.5% of the wavelength at a resonant operating frequency. By using a short probe pin the antenna can be excited easily. The two truncated opposite corners technique is used to obtain the circular polarized operation by selecting an optimal size of truncating. A flat ground plane with an optimal position for the probe pin is used to generate an impedance matching with a wide bandwidth. The CP patch antenna built for IEEE 802.11b/g (2.4 GHz ~ 2.4835 GHz) frequency bands. Measured -10 dB bandwidth is 14.3% and the measured S11, maximum gains and half-power beamwidth are, -41 dB, 8.3 dBi, 75deg respectively. The details of design and experimental results for the proposed design are presented and discussed.

Uni-omnidirectional radial waveguide slot array antenna design for wireless local area network

This paper has considered the development of a low profile unidirectional antenna for WLAN application, performed with frequency range 2.4-2.4835 GHz. The motivation for this work was the need for an effective directional antenna to be used with the access point. The Radial Waveguide Slot Array Antenna (RWSA) is investigated as a low profile, lightly weight, simple but effective, easy to design and fabricate with reasonable cost efficient. The initial element design was first optimized in the structure based on Zeland Fidelity, FDTD (Finite-Difference Time-Domain) with Full-3D EM Simulation for the radiation pattern, and return loss. The second part of this paper deals with producing design relying on optimum simulation results, the antenna tested in terms of return loss, gain and radiation pattern. Finally, experimental trial had been consociate and compared RWSA Antenna with a monopole antenna on an Access point for WLAN by using AirMagnet software. Measurements are conformed to results presented by the prototype simulation.

Novel computation of expecting interference between FSS and IMT-Advanced for Malaysia

This paper deals with the Interference between Fixed Satellite Service (FSS) and IMT-Advanced (4G) for Malaysian environment. The study initiated within detailed calculations of the current and most useful formulas for path loss effect and clutter loss by using the existing parameters of FSS and the most expected parameters for the IMT-Advanced. Thereafter, FSS axis received gain and radiation pattern had been covered. Furthermore, Site shielding, isolation, off-Axis, In-Band and out of band have been discussed in several scenarios. Calculations, analysis and simulation have been done by using Matlab software. Consequently, extracted conclusions had highlighted the subsistent situation and proposal for future work.

On the impact of channel bandwidths and deployment areas clutter loss on spectrum sharing of next wireless systems

Recently, spectrum coexistence and sharing between emerging new technologies and existing wireless systems become a critical issue due to emerging new technologies and spectrum shortage. Lately, IMT system has been allocated in the same frequency band (3400-3600 MHz) along with fixed wireless access services, which means that harmful interference probability may be transpired. Channel bandwidth (BW) and nature of deployment areas of wireless systems are of the main effective factors in spectrum sharing. Spectrum emission mask (SEM) model will be used to study these factors effects beside the interference to noise ratio as a fundamental criterion for coexistence and sharing between systems. The frequency and distance separation and antenna height effects are essential to be investigated to achieve spectrum sharing between systems.