N. N. N. Abd Malik

User's mobility history-based mobility prediction in LTE femtocells network

Seamless and fast handover is one of main goals in Long Term Evolution (LTE) in supporting mobility and maintaining users quality of services. Mobility prediction is a technique to identify future targeted base station in advance, to reduce handover latency, and finally to enhance handover performance in wireless networks. In this paper, mobility prediction via Markov Chains with an input of users mobility history is proposed as a technique to predict the users movement in femtocells deployment. The results show that our proposed method predicts better when random data is 50% and above compared to the existing method. We had also analysed the effect of unavailable base station to the accuracy of the prediction in our proposed method. From the analysis, it is found that, the length of time collecting the data for the database effect the prediction accuracy in certain duration.

Miniaturized microwave modified Koch fractal Hairpin Filter with harmonic suppression

Designing a filter with harmonic suppression capability without adding any external filtering capacitors or notch filter is a big challenge. The paper presents the design of a compact microstrip bandpass filter having integrated harmonic suppression capability. The filter operates at a center frequency of 900 MHz. The structure chosen is the Hairpin Filter. The conventional hairpin is modified by integrating with Koch fractal shaped structure for miniaturisation and harmonic suppression capability. The filters were simulated and optimized using electromagnetic simulation software. Integration of fractal shaped structure into microstrip filters can be used as harmonic suppressor. In addition, reduction in size is also attainable. Second harmonic suppression of up to −35 dB is achieved for the fractal shaped Hairpin Filter, FSF, design.

Evaluation on optimum geometrical of linear node array for self-organization in a wireless sensor network

A novel approach which combines an adaptive linear antenna array and a non-linear function of particle swarm methodology has been developed to estimate the performance of antenna gain in the presence of sensor node geometry location uncertainties. The randomness of sensor nodes geometry location can produce higher energy consumption as it permits the generation of high peaks in radiation beampattern performance. It is shown in simulations that the method is powerful in term of required main beam angle and side lobe level reduction. Results indicate an improve performance in term of radiation beampattern and motivate exploiting this newly-developed optimum method in node geometrical location strategies of WSNs.

Collaborative beamforming null-steering array for wireless sensor networks

This paper presents a method of collaborative beamforming (CB) of organizing sensor node location in linear array for wireless sensor network (WSN). Appropriate Appropriate selection of active CB nodes and cluster are needed each time to perform CB in WSNs. The nodes are modeled in linear array organization in order to perform as a perform as a linear antenna array (LAA). This newly proposed proposed CB null-steering linear array (CBNL) that is able to able to solve the null-steering problem is then presented. presented. Performances in the form of normalized power power gains are given. Analyses obtained are compared with with previous work. The findings showed an enhanced CBNL CBNL that posses null-steering capability.

Reduced size harmonic suppressed fractal dipole antenna with integrated reconfigurability

Reduced size frequency reconfigurable fractal dipole antenna with harmonic suppression capability is presented in this paper. The proposed antenna consists of a narrow band radiating element, stub-filters and taper balun, producing harmonic suppression characteristics. In order to investigate the antenna performance, an extensive simulation (by CST and HFSS) and measurement works have been carried out. This technique is suitable for creating reconfigurable antenna with harmonic suppression or for single band antennas.

Simple design approach of dual-band printed antenna using graphical approximations

Dual operation antennas have gained importance in the development of compact structures. In this paper, a simple approach using graphical approximations is presented for the design of a dual-band antenna. An example of dual-band operation is for the GPS (Global Positioning System) satellite reception with frequencies in the L-band. The chosen antenna is the rectangular microstrip patch having two equal size radiating elements, each operates at a different frequency within the L-band. A mathematical software is used for computing and correlating the relevant design formulae.