Kamarul Noordin

Abstract: Recent trend shows that one of the crucial problems faced while using radio frequency to track the objects is the inconsistency of the signal strength reception, which can be mainly due to the environmental factors and the blockage, which always have the most impact on the tracking accuracy. Besides, three dimensions are more relevant to a warehouse scanning. Therefore, this study proposes a highly accurate and new three-dimensional (3D) radio frequency identification-based indoor tracking system with the consideration of different attenuation factors and obstacles. The obtained results show that the proposed system yields high-quality performance with an average error as low as 0.27m (without obstacles and attenuation effects). The obtained results also show that the proposed tracking technique can achieve relatively lower errors (0.4 and 0.36 m, respectively) even in the presence of the highest attenuation effect, e = 3.3 or when the environment is largely affected by 50% of the obstacles. Furthermore, the superiority of the proposed 3D tracking system has been proved by comparing with other existing approaches. The 3D tracking system proposed in this study can be applicable to a warehouse scanning.

Abstract: This study proposes an efficient and accelerated Intelligent Ray-Tracing (IRT) algorithm based on Binary Angle Division (BAD) technique for radio signal prediction in indoor area. The intelligent features of the proposed IRT can skip the processing of the unnecessary signals based on the invalid region and reduce the number of candidate objects (obstacles) as well as their edges while performing ray-object intersection tests, which can make the algorithm faster as well as more accurate. The obtained results are compared with the existing indoor ray propagation methods to prove the superiority of the proposed IRT technique in terms of both computational efficiency and accuracy of signal prediction.

Abstract: In this paper, we exploit the potential of positioning technologies in wireless broadband communications, which are based on worldwide interoperability for microwave access (WiMAX), in particular the IEEE802.16* standards. By utilizing the additional features in WiMAX including multiple input multiple output (MIMO), adaptive modulation and coding (AMC), beamforming, relay station and power control, we believe that the features can be used for enhancing the location estimation accuracy in location services.

Abstract: In this paper, we propose a novel cross-layer approach of opportunistic scheduling to increase system throughput for IEEE 802.16 downlink transmission. Traditionally wireless users are scheduled according to the type of their subscribed service. The key idea of this paper is to combine hierarchical modulation with opportunistic scheduling, which not only yields a larger over-all system throughput, but also maintains the fairness determined by the type of traffic. As shown by the provided simulation results, the total information capacity for non real-time user is increased without penalising much on the real-time user.

Abstract: The traditional layered-protocol architecture seems to be inefficient in wireless network environment as the wireless channel is time-varying in nature. The IEEE 802.16 standard which the WiMAX system is based upon is also designed according to such layered-protocol stacks. To obtain overall performance gain however, cross-layer optimization is essential. In this paper, we propose a cross-layer optimization architecture for WiMAX system. It consists of a cross-layer optimizer which acts as an interface between MAC and PHY layers. It gathers and optimized the parameters from both layers to achieve optimum performance gain. Preliminary simulations were conducted to justify the need for cross-layer optimization.