Performance measurements and analysis of the existing wireless communication technology in Iraq.

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel UniversityIraq may be considered as the largest wireless market in the Gulf region. A key driving factor in the market of wireless communication, it has seen enormous growth in the mobile phone market over the last five years leading to almost 24 million subscribers in 2011. Moreover, there are several technologies and services working in Iraq; three GSM Operators, three CDMA national operators and three CDMA provinces operators. The recent growth in the mobile phone market is based on the Global System for Mobile (GSM) communications and Code Division Multiple Access (CDMA) standards creating the next-generation wireless technologies in the Iraqi Wireless Communication market. One of the essential issues of this research is to investigate the performance of the decreased Quality Of Service (QoS) caused by interferences in the services on GSM/CDMA operators in Iraq. Many issues should be studied and taken into consideration, such as; does the Multi-Coalition Forces cause the interferences, jamming, higher rate of calls drop and false ringing; or are they caused by bad design and planning? Do we need to optimise our network due to the large number of users? All these factors are investigated and the measurements of most service providers and government agencies will be gathered. A detailed analysis was included from the providers with measurements of performance and the reasons for the deterioration of wireless services. The novel contributions of this thesis is the extensive radio measurement campaign over the three mobile an CDMA operator networks and the analysis and recommendations that were drawn to suggest the best approach to improve the QoS of Wireless communication technologies. Awareness of actual reasons behind the deterioration of services will be raised to the Iraqi Government, CMC and the wireless service providers

Numerical study on failure process of aluminium plate subjected to normal impact by hemispherical projectiles

In this paper a study is presented on the numerical analysis of the failure process of aluminium armour plate subjected to normal impact by hemispherical projectiles. The perforation process has been simulated by the application of 3D analysis using IMPACT dynamic FE program suite. The comparison on the elements size of meshing towards failure mode was observed and evaluated. The material behaviour of the target plate was approximated by an appropriate constitutive relation. The study covered different size of meshing element on target plate as well as different level of impact velocities. Different failure modes for each case were found. For low speed impact condition a petalling was observed, whereas for high speed impact a radial neck along with a holes enlargement was observed with better and uniform perforation mode. The deformation and failure mode of the impacted target plate will be given special attention in this investigation

GAME THEORETIC APPROACH TO RADIO RESOURCE MANAGEMENT ON THE REVERSE LINK FOR MULTI-RATE CDMA WIRELESS DATA NETWORKS

This work deals with efficient power and rate assignment to mobile stations (MSs) involved in bursty data transmission in cellular CDMA networks. Power control in the current CDMA standards is based on a fixed target signal quality called signal to interference ratio (SIR). The target SIR represents a predefined frame error rate (FER). This approach is inefficient for data-MSs because a fixed target SIR can limit the MS's throughput. Power control should thus provide dynamic target SIRs instead of a fixed target SIR. In the research literature, the power control problem has been modeled using game theory. A limitation of the current literature is that in order to implement the algorithms, each MS needs to know information such as path gains and transmission rates of all other MSs. Fast rate control schemes in the evolving cellular data systems such as cdma2000-1x-EV assign transmission rates to MSs using a probabilistic approach. The limitation here is that the radio resources can be either under or over-utilized. Further, all MSs are not assigned the same rates. In the schemes proposed in the literature, only few MSs, which have the best channel conditions, obtain all radio resources. In this dissertation, we address the power control issue by moving the computation of the Nash equilibrium from each MS to the base station (BS). We also propose equal radio resource allocation for all MSs under the constraint that only the maximum allowable radio resources are used in a cell. This dissertation addresses the problem of how to efficiently assign power and rate to MSs based on dynamic target SIRs for bursty transmissions. The proposed schemes in this work maximize the throughput of each data-MS while still providing equal allocation of radio resources to all MSs and achieving full radio resource utilization in each cell. The proposed schemes result in power and rate control algorithms that however require some assistance from the BS. The performance evaluation and comparisons with cdma2000-1x-Evolution Data Only (1x-EV-DO) show that the proposed schemes can provide better effective rates (rates after error) than the existing schemes

Initial synchronisation of wideband and UWB direct sequence systems: single- and multiple-antenna aided solutions

This survey guides the reader through the open literature on the principle of initial synchronisation in single-antenna-assisted single- and multi-carrier Code Division Multiple Access (CDMA) as well as Direct Sequence-Ultra WideBand (DS-UWB) systems, with special emphasis on the DownLink (DL). There is a paucity of up-to-date surveys and review articles on initial synchronization solutions for MIMO-aided and cooperative systems - even though there is a plethora of papers on both MIMOs and on cooperative systems, which assume perfect synchronization. Hence this paper aims to ?ll the related gap in the literature

Chinese cellular telecommunications in the past and the 21st century

Cellular telecommunication technology is one of the hottest topics of the last two decades. The annual rate of user growth is more than 30 percent. It began with the first generation (1G) networks and bloomed with second generation (2G) of cellular technologies. New third generation cellular (3G) technologies aim at offering high-speed, superior-quality information service to mobile subscribers. [2] The Chinese cellular market is developing with unbelievable speed. China launched its first cellular network in 1987. At the end of 2002, it was the biggest wireless market in the world, with more than 200 million subscribers. [56] Technologies used in the migration from the 2G networks to the 3G networks are referred to as 2.5 generation or 2.5G. It is no doubt that the 3G pattern selected in China will deeply affect the competition among the 3G technologies. This thesis will forecast the 3G systems to be selected for use in China. It will begin with the 1G and 2G networks and then look into the 2.5 G and the 3G cellular telecommunication technologies in more detail. Analysis the history, culture and business conditions in China will follow. Finally, this paper will make a prediction of the principal Chinese 3G technologies that will be chosen based on analyzing concrete information. An examination of other Asia markets, such as the 3G markets in Japan, and South Korea will be included. The conclusion of this thesis is that WCDMA (Wideband Code Division Multiple Access), a 3G technology that is developed and supported by European telecommunication manufacturers, will take the lion\u27s share of the Chinese 3G market, about 65% to 70%. Another technology, CDMA2000, will take more than 20% of the Chinese 3G market share. There is also a Chinese oriented 3G technology named TD-SCDMA (Time Division Synchronous Code Division Multiple Access). With the Chinese government\u27s support, it will collect the remaining 10% to 15% market share

In situ method for power re-equalization of wavelength pulses inside of OCDMA codes

A simple in-situ method to equalize power among individual wavelengths pulses representing two-dimensional wavelength-hopping time-spreading OCDMA code originally generated by a fibre Bragg grating-based OCDMA encoder is presented. Experimental data obtained in a field-based multiuser OCDMA testbed shows that applying this method results in system performance enhancements which was demonstrated by observing improved bit error rate (BER) during the field trials

Multi-carrier transmission techniques toward flexible and efficient wireless communication systems

制度:新 ; 文部省報告番号:甲2562号 ; 学位の種類:博士(国際情報通信学) ; 授与年月日:2008/3/15 ; 早大学位記番号:新470

Wireless technology: current status and future directions

Wireless Technology is expected to be the dominant mode of access technology in the future. Besides voice, a new data range of services such as multimedia and high speed data are being offered for delivery over wireless network. Mobility will be seamless, realizing the concept of persons' being in contact anywhere, at any time. Throughout this paper, we review the long, interesting development of wireless communication in the past, examine the current progress in standards and technologies, and finally discuss possible trends for wireless communication solutions

Performance Evaluation of CDMA Reverse Links with Imperfect Beamforming in a Multicell Environment Using a Simplied Beamforming Model

Reverse link capacity of a direct-sequence codedivision multiple-access (DS-CDMA) system in a multicell environment has been studied recently, and significant capacity improvements due to the use of beamforming have been observed. However, system performance with beamforming will be affected by several impairments, such as direction of arrival estimation errors, array perturbations, mutual coupling, and signal spatial spreads. In this paper, reverse link performance of CDMA systems with beamforming under these impairments (imperfect beamforming) is investigated. A simplified beamforming model is developed to evaluate the system performance in terms of user capacity, bit-error rates (BER), and outage probabilities. Both signalto-interference-ratio-based power control and strengthbased power control are considered in this paper. The capacity and BER degradations due to different impairments are shown, and outage probabilities under different power control schemes are examined