Jamil Sultan

Downlink performance of handover techniques for IEEE 802.16j multi-hop relay networks

Multi-hop relay (MR) is a well-accepted economical approach to significantly enhance the coverage, throughput and system capacity of the mobile wireless broadband. In this paper, we performed simulation study of the performance of various handover techniques for time division duplex (TDD) - orthogonal frequency division multiple access (OFDMA) based two-hop cellular networks at different mobile station (MS) speeds. The simulated handover techniques are hard handover (HHO), macro diversity handover (MDHO) and fast base station switching (FBSS). The performance metric is the overall average downlink (DL) carrier to interference and noise ratio (CINR). Results show that MDHO outperforms FBSS and HHO.

Topology-aware macro diversity handover technique for IEEE 802.16j multi-hop cellular networks

Macro diversity handover (MDHO) is the process by which a mobile station (MS) maintains connection with two or more access stations called a diversity set. In this study, the authors propose a topology-aware MDHO technique for time division duplex (TDD)-orthogonal frequency division multiple access (OFDMA)-based interference-limited multi-hop cellular networks. The proposed MDHO receives all the data signals transmitted by the diversity set members of the MS. It ensures that the topology of the diversity set members is always fully exploited. The efficiency of the proposed MDHO is validated using a mathematical model and computer simulation. The performance evaluation is carried out for different relay station (RS) transmitted powers. Evaluation results show that the proposed MDHO significantly outperforms the conventional MDHO. Over the MDHO regions in which the diversity set members are multi-hop relay base station (MR-BS) and RS, the proposed MDHO offers a carrier to interference and noise ratio gain and a spectral efficiency gain of as much as 4.5 dB and 0.85 bps/Hz, respectively, compared to the conventional MDHO.

An enhanced macro diversity handover technique for IEEE 802.16j

In this paper, we propose an enhanced macro diversity handover (MDHO) technique for TDD-OFDMA-based interference-limited IEEE 802.16j multi-hop relay cellular networks. The proposed MDHO ensures that the topology of the diversity set members is always fully exploited. Evaluation results show that the proposed MDHO significantly outperforms the conventional MDHO and offers a CINR gain of as much as 4.13dB.

Performance evaluation of PAPR in OFDM for UMTS-LTE system

Next generation mobile telecommunication networks will provide high data rates needed for multimedia rich applications as the demand in mobile broadband services is expected to increase in the coming years. Orthogonal Frequency Division Multiplexing (OFDM) technique has been increasing its popularity as a transmission scheme for several radio technologies. One of the challenging issues in OFDM technique is its high peak-to-average power ratio (PAPR). This paper studies the performance of PAPR in long term evolution (LTE) of universal mobile telecommunications system (UMTS). The implementation will be based on specifications and protocols from 3rd Generation Partnership Project (3GPP) work groups. The simulator used to simulate UMTS-LTE environment has been developed in Matlab which follows the standard according to UMTS-LTE physical layer transmission scheme. Evaluation results show that reduction of PAPR can be seen in UMTS-LTE model compared to conventional OFDM model.

Spectral efficiency of mobile WiMAX networks employing adaptive modulation and coding

Mobile WiMAX technology is based on IEEE 802.16e standard and considered as one of the most prominent solutions capable to provide high speed access in metropolitan areas. Due to limited radio resources, it is necessary to consider radio resource efficiency. This paper investigates the spectral efficiency gain achieved when applying link adaptation techniques on the downlink (DL) of the IEEE 802.16e-based mobile WiMAX networks. The performance evaluation is carried out using a system-level simulation. Evaluation results show that system using adaptive modulation and coding (AMC) significantly outperforms systems using fixed modulation (FM) and adaptive modulation (AM) schemes alone in terms of the spectral efficiency and percentage of successful links.

Technical assesment on Wi-Fi pilot deployment for rural telecommunication in Malaysia

Access to communication can play a pivotal role in the socio-economic development of rural regions in the third world. For affordability, the choice of technology to achieve this is a significant aspect. IEEE 802.11 Wi-Fi is chosen as a cost-effective technology to provide last mile rural connectivity in the East Peninsular of Malaysia. This paper identifies the Wi-Fi concepts deployed and programme implementation by designated service provider. It assesses the designated provider on their planning and implementation of the pilot Wi-Fi. The facilities provided by the designated provider including distribution of access points (APs) are assessed as well. Evaluation results reveal some interesting insights into the problem.

Performance evaluation of macro diversity handover technique for multi-hop relay cellular networks

Macro diversity handover (MDHO) is the process by which the mobile station (MS) communicates with two or more access stations. The list of the access stations is called a diversity set. In this paper, we investigate the performance of an enhanced MDHO technique for TDD-OFDMA-based interference-limited multi-hop relay cellular networks. The enhanced MDHO exploits all the data signals transmitted by the diversity set members of the MS. The performance evaluation is carried out using a system-level simulation. Simulation results show that the enhanced MDHO is more spectrally efficient than conventional MDHO, fast access station switching (FASS) and hard handover (HHO) techniques.

Downlink performance of a relay-enhanced mobile WiMAX networks

Mobile WiMAX is based on IEEE 802.16e standard to provide fixed and mobile broadband wireless access from anywhere within the metropolitan area network (MAN). Multi-hop relaying is a cost-effective approach to significantly extend the coverage and enhance the throughput and capacity of the WiMAX networks. In this paper, we evaluate the downlink (DL) performance of a relay-enhanced WiMAX networks. The effect of the number of implemented relay stations (RSs) on the performance of the mobile WiMAX networks is studied and evaluated. The performance evaluation is carried out using a system-level simulation developed in MATLAB software. The performance evaluation metrics are the average DL carrier-to-interference-and-noise ratio (CINR) and the average DL spectral efficiency. Evaluation results show that as the number of RSs is increased, the performance of the mobile WiMAX is significantly improved. However, in the scenario in which 4 RSs are deployed, the maximum achieved average DL CINR and the average DL spectral efficiency gains are 11.58 dB and 115.44%, respectively, compared to the scenario without RS.