Despite that we are in the midst of profound changes in communications technologies, there is a remarkable gap in the International Relations literature devoted to exploring the implications of these changes. In part, this can be attributed to the discipline’s conservative tendencies; generally, International Relations theorists have resisted studying major discontinuity in the international system. The few studies that do attempt to account for change typically focus on modes of production or destruction as determinant variables. Though there are rare exceptions, many of them also tend towards a form of mono-causal reductionism. When considered at all, communications technologies are viewed through the prism of, or are reduced to, these other factors. This study seeks to remedy this gap by examining the relationship between large-scale shifts in modes of communication and “world order” transformation -- the structure or architecture of political authority at a world-level. Drawing from the work of various “medium theory” scholars, such as Harold Innis and Marshall McLuhan, the study outlines an open-ended, non-reductive theory at the core of which is the argument that changes in modes of communication facilitate and constrain social forces and ideas latent in society. This hypothesized process can be likened to the interaction between species and a changing natural environment: new communications environments “favour” certain social forces and ideas by means of a functional bias towards some and not others, much the same as environments determine which species prosper by “selecting” for certain physical characteristics. In other words, social forces and ideas survive differentially according to their “fitness” or match with the new communications environment -- a process that is both open ended and contingent. The study is organized into two parts: Part one examines the relationship between printing and the medieval to modem world order transformation in Europe; Part two examines the relationship between new digital-electronic-telecommunications (called “hypermedia”) and the modem to postmodern world order transformation. The study suggests that the hypermedia communications environment is contributing to the dissolution of modern world order by facilitating the transnationalization of production, the globalization of finance, the rise of complex, non-territorial social networks, and the de-massification of “national” identities. The hypermedia environment is also helping to re-focus security concerns from an inter-national to an intra-planetary context. While it is far too early to provide a clear outline of the emerging postmodern world order, the trends that are unearthed in this study point away from single mass identities, linear political boundaries, and exclusive jurisdictions centred on territorial spaces, and towards multiple identities and non-territorial communities, overlapping boundaries, and non-exclusive jurisdictions. / Arts, Faculty of / Political Science, Department of / Graduate

User modeling enables in the computation of the traffic density in a cellular network, which can be used to optimize the placement of base stations and radio network controllers as well as to analyze the performance of resource management algorithms towards meeting the final goal: the calculation and maximization of network capacity and throughput for different data rate services. An analytical model is presented for approximating the user distributions in multi-cell third generation wideband code division multiple access (WCDMA) networks using 2-dimensional Gaussian distributions by determining the means and the standard deviations of the distributions for every cell. This model allows for the calculation of the inter-cell interference and the reverse-link capacity of the network. An analytical model for optimizing capacity in multi-cell WCDMA networks is presented. Capacity is optimized for different spreading factors and for perfect and imperfect power control. Numerical results show that the SIR threshold for the received signals is decreased by 0.5 to 1.5 dB due to the imperfect power control. The results also show that the determined parameters of the 2-dimensional Gaussian model match well with traditional methods for modeling user distribution. A call admission control algorithm is designed that maximizes the throughput in multi-cell WCDMA networks. Numerical results are presented for different spreading factors and for several mobility scenarios. Our methods of optimizing capacity and throughput are computationally efficient, accurate, and can be implemented in large WCDMA networks.

Reliable communication over the noisy channel has become one of the major concerns in the field of digital wireless communications. The low density parity check codes (LDPC) has gained lot of attention recently because of their excellent error-correcting capacity. It was first proposed by Robert G. Gallager in 1960. LDPC codes belong to the class of linear block codes. Near capacity performance is achievable on a large collection of data transmission and storage.In my thesis I have focused on hardware implementation of (3, 6) - regular LDPC codes. A fully parallel decoder will require too high complexity of hardware realization. Partly parallel decoder has the advantage of effective compromise between decoding throughput and high hardware complexity. The decoding of the codeword follows the belief propagation alias probability propagation algorithm in log domain. A 9216 bit, (3, 6) regular LDPC code with code rate ½ was implemented on FPGA targeting Xilinx Virtex 4 XC4VLX80 device with package FF1148. This decoder achieves a maximum throughput of 82 Mbps. The entire model was designed in VHDL in the Xilinx ISE 9.2 environment.

Includes bibliography. / South Africa needs a modern, sophisticated telecommunications network to ensure economic development and political stability. The same network must also provide affordable and reliable service to a great percentage of the population. The telecommunications industry is currently monopolised by Telkom, a state-owned business enterprise (SBE), and does not appear capable of meeting these basic requirements. The purpose of this paper is to present a case for restructuring Telkom and liberalising the telecommunications industry to best serve the needs of the South African economy. The objective for restructuring the telecommunications industry must be to maximise long-term consumer welfare for all South Africans. This paper argues that consumer welfare will be maximised only by dismantling the statutory monopoly structure and moving toward a highly competitive, privately owned telecommunications industry. The economic issues, of course, cannot be discussed realistically without reference to political, social and historical variables, all of which are also considered. By focusing primarily on economic issues, however, this paper strives to avoid the ideological disputes which usually surround discussions of state ownership. This paper focuses on the telecommunications industry because it represents the single most important infrastructural component in a modern economy. It also presents a unique opportunity if managed well, and a grave danger if allowed to continue in its current structure.

Bibliography: pages 233-235. / The CCITT X.400 Message Handling System resides in the Application Layer of the seven-layer Reference Model for Open Systems Interconnection. It bypasses the services of the Presentation Layer completely to interact directly with the Session Layer. The objectives of this thesis are to show how the general Session Layer may be tailored to be minimally conformant to the requirements of X. 400; to produce a formal specification of this session layer; and to show how this session layer may be implemented on a real system. The session services required by X. 400 are those of the Halfduplex, Minor Synchronization, Exceptions and Activity Management functional units of the CCITT X.215 Session Service Definition. These services, and particularly their use by X.400, are described in detail. State tables describing these services are derived from the general session service state tables. Those elements of the CCITT X. 225 Session Protocol Specification which are required to provide only those services required by X. 400 are described in detail. State tables describing this session protocol are derived from the general session protocol state tables. A formal specification of the session layer for X.400 is presented using the Formal Description Technique Estelle. This specification includes a complete session entity, which characterizes the entire session layer for X.400. A session entity for supporting X.400 is partially implemented and interfaced to an existing X.400 product on a real system. Only the Session Connection Establishment Phase of the session protocol is implemented to illustrate the technique whereby the entire session protocol may be implemented. This implementation uses the C programming language in the UNIX operating system environment.

[pt] Este trabalho analisa o desempenho de sistemas de micro-ondas em visibilidade em função do comportamento dos equipamentos (taxa de falha e tempo de reposição) e das características de propagação (desvanecimento). Os modelos estudados correspondem às configurações dos sistemas usuais e diversos resultados numéricos são apresentados para ilustrar a formulação teórica. A confiabilidade dos equipamentos é estimada a partir de dados relativos aos sistemas da EMBRATEL ( Empresa Brasileira de Telecomunicações) e na parte de propagação são discutidas algumas expressões semi-empíricas para avaliar o efeito desvanecimento rápido. / [en] This work deals with the performance os line-of-sight microwave links as a function of equipment behavior (failure rate and reposition time) and the propagation caracteristics (fading). The studied models correspond to usual system configurations and several numerical results are presented to ilustrate the theoretical formulation. The equipment reliability is estimated from EMBRATEL ( Brasilian Telecommunications Enterprise) systems data and some semi-empirical expressions are discurred to take into account the fast fading effect.

The performance of a nonlinear satellite channel using QPSK (Quaternary Phase Shift Keying) and MSK (Minimum Shift Keying) has been studied by computer simulation. In the simulation, the pseudo randomly generated input data stream modulates the carrier and this modulated carrier passes through the typical satellite communication link, that consists of a transmit earth station, a satellite transponder, and a receiving earth station. All the signals used in the simulation procedure are real-valued and are transformed back and forth between time and frequency domains depending on the necessity by the Fast Fourier Transform (FFT) or Inverse Discrete Fourier Transform (IDFT). The simulation result represented as average Bit Error Rate (BER) gives the basis for comparison of the performance in various link conditions such as linearity, nonlinearity, band-limited and noisy channels which are expected to be encountered in practical situations. / Master of Science / incomplete_metadata

Our society is undergoing a wireless revolution in which there is a rapidly increasing demand for personal communication services (PCS). Several alternate technologies have been proposed to meet this demand, including a 1.25 MHz CDMA system. It is important to provide system designers with tools to accurately predict system performance. Analytical techniques are useful for providing general information on system performance, but may not fully capture the complexities of the mobile radio channel needed to accurately predict the performance of complex system designs. This thesis presents a novel simulation technique in which a CDMA system is modeled by software, but the channel impulse response model is derived from actual measurements. This thesis describes a bit error simulation tool for a 1.25 MHz bandwidth CDMA system. The simulator incorporates measurement-based channel impulse response data with the simulated CDMA system. Bit error rate for COMA is simulated under a variety of actual channel conditions, including heavy urban, urban, suburban and rural environments. Simulation results for both 915 MHz and 1920 MHz are presented. Vertical and circular antenna polarization are compared. In the simulation, a RAKE receiver is implemented, the advantage of this RAKE receiver implementation is demonstrated by comparison to a single correlation receiver. Results for outage probability are also presented. / Master of Science

Very small aperture terminal (VSAT) networks offer a solution to the increasing demand for low-density voice and data communications. Spread Spectrum and single-channel-per-carrier (SCPC) transmission techniques work well for multiple access purposes while allowing the earth station antennas to remain small. Direct sequence code division multiple access (DS-CDMA) is the simplest spread spectrum technique to use in a VSAT network, since a frequency synthesizer is not required for each terminal. This thesis examines DS-CDMA and SCPC Ku-band VSAT satellite systems for low-density (64 kbps or less) communications. It develops methods for calculating PN coding cross-correlation interference losses and satellite transponder effects, and it includes these losses in a performance analysis of 50 channel full mesh and star network architectures. It demonstrates selection of operating conditions producing optimum performance. / Master of Science

The use of communication satellites operating above 10 GHz has prompted research on the attenuating effects of rain on these signals. Frequency scaling, a technique where attenuation at one frequency can be scaled up (or down) to another frequency, can extend the known data base of propagation impairments. This thesis studies the ratios of attenuations in frequency pairs 14/11, 30/20, 30/11, and 20/14 GHz. The attenuation data were derived from a year-long propagation experiment which used a dual-polarized radar to estimate drop size distributions on a slant path between Blacksburg, Virginia, and the Intelsat VA F10 satellite. The effect of varying drop size distributions on attenuation ratios is discussed. An uplink power control simulation is developed using the attenuation ratios. Attenuation on the uplink path is estimated by scaling the measured downlink attenuation by the appropriate attenuation ratio. The evidence suggests that an uplink power control scheme using drop size distribution-based attenuation ratios offers improvement in satellite link reliability during rain storms. / Master of Science