Dissertations / Theses: 'TDMA'

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Kane, Roma. "Multiuser TDMA channel estimation." Diss., Columbia, Mo. : University of Missouri-Columbia, 2004. http://hdl.handle.net/10355/5810.

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Thesis (M.S.)--University of Missouri-Columbia, 2004.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (June 30, 2006) Vita. Includes bibliographical references.

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Persson, Markus. "Uplink TDMA Potential in WCDMA Systems." Thesis, Linköping University, Department of Electrical Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11399.

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The evolvement of the uplink in the third generation mobile telecommunication system is an ongoing process. The Enhanced Uplink (EUL) concept is being developed to meet the expected need from more advanced services, like video streaming and mobile broadband. One idea for further improvement in the EUL concept is to introduce Time Division Multiple Access (TDMA), which is studied in this master thesis.

The master thesis assignment is to study the consequences of introducing TDMA in EUL. The goal has been to identify the gains and problems, and how they can be handled. A derived theoretical framework and system simulations, using a radio network simulator, are used.

The overall conclusion is that there is a potentially large gain with an introduction of TDMA in EUL. Simulations in favorable conditions have shown that the system throughput can increase by 100% when there are only User Equipment (UE) that are using EUL in the system and by 50% when there is a mix of speech and EUL UE’s. When using TDMA the uplink load also shows improvements, the mean is generally higher but the variance is generally smaller.

Due to major differences in experienced interference between passive and active UE’s, the signal quality will vary a lot. The big variation in signal quality is identified as the main problem with introducing TDMA in EUL. It is shown that this problem can generate extreme high uplink load, which have a negative impact both on the resource efficiency and the coverage.

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Grönkvist, Jimmi. "Assignment strategies for spatial reuse TDMA." Licentiate thesis, KTH, Signaler, sensorer och system, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1407.

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Oh, Inhee Electrical Engineering &amp Telecommunications Faculty of Engineering UNSW. "Spatial reuse in TDMA wireless networks." Publisher:University of New South Wales. Electrical Engineering & Telecommunications, 2008. http://handle.unsw.edu.au/1959.4/40910.

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In this thesis we investigate the performance of spatial reuse in wireless networks. More specifically, we investigate the performance of location-based spatial reuse built upon the identification of links in the network that form Collision-Free Sets (CFSs). We develop algorithms that efficiently find such CFSs. The main focus of this thesis is the application of our CFS-based algorithms to emerging WiMAX (Worldwide Interoperability for Microwave Access) networks. However, we will also apply our CFS-based algorithms to smaller scale networks, as well as to the issue of QoS routing. This thesis makes several contributions. We first show how CFSs can be found within polynomial time in small scale wireless networks. We then probe how CFSs can be used to enhance network efficiency when location is available. We also explore how CFS determination is affected by location error, determining what level of location error renders the use of CFSs ineffective. In this context, we discuss the density of access points required to ensure CFS-based spatial reuse remains effective. We then focus on the use of CFSs in emerging multihop WiMAX networks, showing in detail how enhanced spatial reuse is delivered. The spatial reuse gains are probed both in the presence of realistic channel conditions and realistic location errors. Within the context of the IEEE 802.16 standard we show how CFSs can enhance, by factors of two, the VoIP capacity of multihop WiMAX networks. We also discuss how our CFS algorithms can be applied to other ongoing efforts aimed at improving VoIP capacity in WiMAX networks. Finally, an application of our CFS algorithms in the context of QoS routing is studied. Specifically, we develop a two-hop QoS routing protocol that guarantees QoS specifications by securing higher bandwidth for the chosen routes.

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Williams, John Edward Brunton. "Intelligent multimode TDMA systems for PCS." Thesis, University of Southampton, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242220.

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PINHO, SERGIO FRANCA DE. "RADIOLOCATION IN SYSTEMS OF TECHNOLOGY TDMA." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2004. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=5573@1.

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EMPRESA BRASILEIRA DE TELECOMUNICAÇÕES
Este trabalho é um estudo sobre radio-localização de terminais móveis em sistemas de tecnologia TDMA. Pela legislação americana e também pela extrema competitividade entre operadores de telefonia na conquista de novos mercados e de provisão de novos serviços, técnicas que permitam a localização do terminal móvel têm sido intensamente pesquisadas. Uma dessas técnicas usa o tempo de chegada (TOA) para estimar a posição do móvel. Como não se tem acesso à medida original de TOA, deve-se estimar TOA a partir de TA (Timing Advance). O valor de TA é enviado pela ERB a EM por meio de um canal de sinalização, que é designado a partir de um conjunto finito de valores discretos que permite que se extraia contornos circulares em torno de cada antena de recepção, a posição do móvel é melhor na interseção de todos aqueles contornos estimados. O erro resultante na estimação do TOA pode ser grande pela ação do erro aleatório e se o TA errado for selecionado. Dado que se sabe somente o TA, o problema é encontrar um estimador e seu erro para o TOA real. Embora a literatura cite diversos processos para solução desse problema, a título de distinguir entre estes e o aqui proposto, denominaremos o processo aqui discutido de Refinamento Sucessivo da Incerteza.
This work is a study about radiolocation of mobile terminals in TDMA systems. In agreement with the American legislation and also because of the extreme competitiveness among wireless operators in order to conquer new markets and provision new services, techniques that allow the localization of the mobile terminal have been intensely researched. One of these techniques uses time of arrival (TOA) to estimate the mobile position. Since the original TOA measurement is not accessible, TOA should be estimated from TA (Timing Advance). The value of TA is sent by the BTS to the MS by means of a signaling channel, which is assigned from a set of discrete values that allows one to draw circular contours around each receiving antenna, the location of the mobile is the best intersection of all those estimated contours. The resultant error in estimated TOA might be large by random error and if the wrong TA will be selected. Given that only TA is know, the problem is to find an estimator and its error for the actual TOA. Although literature mentions diverse processes to solve this problem, in order to distinguish between these and the considered here, we will call the process discussed here of Successive Refinement of the Uncertainty.

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Wang, Li. "TDMA digital mobile radio transmission system." Thesis, University of Liverpool, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240335.

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Aquino, Luiz Carlos Faray de. "Modulação codificada para sistemas moveis TDMA." [s.n.], 2001. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259739.

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Orientador: Renato Baldini Filho
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Mestrado

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Alakhond, Sabah J. 1958. "FRAME SYNCHRONIZATION IN TDMA SYSTEMS (REFRAMING)." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/291423.

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Good, Stephen D. "A Study into the Tradeoffs Between TDM / MF-SCPC and TDM / MF-TDMA Transport Options to Support IP-Based Multimedia Applications Under Different Load Conditions Within a Point-to-Multipoint Satellite Network." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/32730.

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This thesis provides the reader with an overview of the many elements that are involved in geosynchronous satellite point-to-multipoint Internet Protocol (IP)-based multimedia communications design and also takes a deep dive into the analysis of a real-life scenario, using the TDM / MF-SCPC and TDM / MF-TDMA media access techniques. This thesis starts with a discussion of satellite network topologies utilized within point-to-multipoint satellite communications followed by an overview of the satellite communications channel. A discussion on the intelligent and proper selection of modulation and coding follows. Descriptions and characteristics of the satellite access technologies chosen to be analyzed are next followed by a detailed description of Forward Error Correction (FEC) techniques and a discussion on network-wide tradeoffs so selecting different options. The thesis then presents the results of a real-life scenario, investigating both TDM / MF-SCPC and TDM / MF-TDMA media access technique options, pointing out the tradeoffs brought to the forefront earlier in the study. The major takeaway is that there does not exist a one-size-fits-all solution that works for each and every scenario.
Master of Science

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Grönkvist, Jimmi. "Interference-based scheduling in spatial reuse TDMA." Doctoral thesis, KTH, School of Electrical Engineering (EES), 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-441.

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Spatial reuse TDMA has been proposed as an access scheme for multi-hop radio networks where real-time service guarantees are important. The idea is to allow several radio terminals to use the same time slot when possible. A time slot can be shared when the radio units are geographically separated such that small interference is obtained. The transmission rights of the different users are described with a schedule.

In this thesis we will study various aspects of STDMA scheduling. A common thread in these various aspects is the use of an interference-based network model, as opposed to a traditional graph-based network model. While an interference-based network model is more complex than a graph-based model, it is also much more realistic in describing the wireless medium. An important contribution of this thesis is a comparison of network models where we show that the limited information of a graph model leads to significant loss of throughput as compared to an interference-based model, when performing STDMA scheduling.

The first part ot this thesis is a study of assignment strategies for centralized scheduling. Traditionally, transmission rights have been given to nodes or to links, i.e., transmitter/receiver pairs. We compare these two approaches and show that both have undesirable properties in certain cases. Furthermore, we propose a novel assignment strategy, achieving the advantages of both methods.

Next we investigate the effect of a limited frame length on STDMA schedules. We first show that the required frame length is larger for link assignment than for node assignment. Further, we propose a novel assignment strategy, the joint node and link assignment, that has as low frame length requirements as node assignment but with the capacity of link assignment.

In the last part of this thesis we describe a novel interfence-based distributed STDMA algorithm and investigate its properties, specifically its overhead requirement. In addition we show that this algorithm can generate as good schedules as a centralized algorithm can.

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Grönkvist, Jimmi. "Interference-based scheduling in spatial reuse TDMA /." Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-441.

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Joung, Jinsoup. "Cochannel interference canceling receivers for TDMA systems." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/21806.

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MELLO, LEONARDO CRUZ. "CHANNEL ALLOCATION COMPARATIVE ANALYSIS FOR TDMA TECHNOLOGY." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2002. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=3115@1.

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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
Os esquemas de alocação fixa de canais - FCA - conferem aos Sistemas de Comunicação Móveis Celulares estabilidade com o custo da necessidade de um pré-planejamento de freqüências, trazendo como conseqüência a baixa tolerância à variabilidade de tráfego. Algoritmos de alocação dinâmica de canais - DCA - tem sido propostos por diversos autores com o intuito de minimizar estes problemas, permitindo ao sistema flexibilidade no momento da escolha do canal candidato para servir a uma ligação. Esquemas de alocação híbrida de canais - HCA, combinam as técnicas de alocação fixa com alocação dinâmica de canais, conferindo ao mesmo tempo estabilidade e flexibilidade ao sistema.Este trabalho compara os algoritmos FCA, DCA e HCA sobre um mesmo cenário de simulação, permitindo analisar o desempenho dos mesmos. O esquema FCA utilizado é o mais simples, onde o primeiro canal com o nível aceitável de relação sinal interferência é escolhido para ser alocado. O esquema DCA utiliza a técnica de Segregação de Canais - CS, permitindo ao sistema maior flexibilidade no momento da escolha do canal candidato, devido a não existência do pré-planejamento de freqüências. O terceiro algoritmo, HCA, combina os dois esquemas anteriores. Ao final, será analisado o impacto de se priorizar o procedimento de handoff utilizando-se a técnica conhecida como Canais de Guarda.
Fixed channel assignment -FCA- brings to the Cellular Communication Systems stability at the cost of the use of frequency planning, leading to low tolerance to traffic variability. Dynamic channel assignment -DCA- algorithms have been proposed by several authors in order to minimize these problems,incorporating flexibility to the system with respect to channel selection. Hybrid channel assignment - HCA- combines the techniques of fixed and dynamic channel assignment, giving to the system stability and flexibility at the same time. This work compares the FCA, DCA and HCA algorithms on the same simulation scenario, allowing a complete analysis of these approaches. The FCA used is the simplest. In this algorithm, the first channel with an acceptable level of signal to interference ratio is chosen to be allocated. The DCA uses the technique of Channel Segregation -CS-, a distributed self-learning algorithm that is shown to yield very good performance. The third algorithm,HCA, combine the two previous techniques. At the end, the impact of prioritizing the procedure of handoff will be analyzed, using the technique known as Guard Channel.

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Ansari, Muhammad Adeel. "TDMA for Low Sampling Rate IR-UWB Receivers." Licentiate thesis, KTH, Kommunikationssystem, CoS, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-96694.

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In UWB communication sampling plays a key role in detection of the transmitted data. There are various methods of data transmission and detection at the receiver. Mostly, the detection methods are based on frequency domain methods. The popular method to lower the sampling rate is the sub-sampling technique, based on frequency of the transmitted signal. A special method like orthogonal frequency division multiplexing (OFDM) is needed to reduce inter symbol interference for a frequency based method. The power consumption associated with higher sampling rates is also a big challenge. Therefore some simple techniques are required to detect data on lower sampling rates without ISI in the multiple user environments and with lower power consumption. If selection of the sampling frequency would be flexible to detect data from multiple users then it could relax the UWB receiver design requirements. In this thesis we developed a transmission and reception methodology with reduced sampling frequency for data detection. In the proposed work, transmitted data is distributed using TDMA frames for all users within fixed time slots for each user. The TDMA technique is being used to achieve low sampling rates and to avoid multiple access interference (MAI). The sampling rate to detect the data of each user can be selected according to number of users and transmission bandwidth. For this purpose each data bit of a user is arranged once in a transmission frame. The data can be detected on frame repetition rate depends on the total number of users. The data of each user can be accessed directly by calculating the total time of each user place within each frame. Since each data bit of one user occurs once in a frame therefore it could be claimed that ISI within the same user has been avoided. The proposed scheme has been tested with 50 MHz, 100 MHz and 500 MHz sampling frequencies for 50 users, 25 users and 5 users respectively by using 2.5 GHz bandwidth. 8-bits of data was transmitted and detected for different users using Matlab and Simulink Models. The results were analyzed in perfect synchronization condition and compared between integrated window energy detector UWB receiver and an UWB receiver using a matched filter. The performances are evaluated on the basis of BER. To observe the impact of synchronization, both receivers were evaluated with some timing mismatch. It is concluded that the scheme works well for the lower sampling rate for both types of UWB receivers stated above. It can also be concluded by observing the results that the UWB receiver using matched filter has better performance in noisy environment compared to energy detector UWB receiver with integrated window. The performance of energy detector UWB receiver with integrated window and UWB receiver with matched filter were also evaluated with timing mismatch. It can be concluded that the UWB receiver with integrated window has better performance compared to UWB receiver using matched filter if the synchronization is not achieved properly. The UWB receiver with matched filter is more vulnerable against timing mismatch compared to UWB receiver with integrated window.
QC 20120612

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Kannah, Ali, and Ghasaq Bahiya. "DESIGN AND IMPLEMENTATION OF WIRELESSHART TDMA STATE MACHINE." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Data- och elektroteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-15463.

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WirelessHART is one of the latest communication standards that have enhanced functionality and robustness. The standard is ideal for applications in control and automation industry. In this work we present an implementation the TDMA state machine of the WirelessHART communication protocol on TinyOS operating system using the nesC language for the Telobs motes. The development was carried out using software reuse principle and involved comparing the state diagram description of the TDMA presented in WirelessHART with that of the time synchronized frequency hopping implementation that was already available for reuse. The work highlights the differences between the TSCH code and the WirelessHART specifications and builds upon the TSCH code to arrive at the WirelessHART TDMA state machine implementation.

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Pawgasame, Wichai, and Wuttisak Sa-Ad. "Self-Organized TDMA protocol for Tactical Data Links." Thesis, Linköpings universitet, Kommunikationssystem, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-72159.

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A Tactical Data Link (TDL) system has been deployed in many military missions as a winning strategy. The performance of a TDL system is governed by the MAC protocol. The MAC protocol that is able to provide more flexibility and high quality of services is more desirable. However, most MAC protocols implemented in current TDL systems are based on a preprogramming TDMA protocol, in which a time slot schedule is fixed. This thesis presents the new self-organized TDMA protocol based on the existing self-organized slot assignment algorithms and the practical military scenarios as the alternative solution to the current preprogramming TDMA protocol. The self-organized TDMA protocol presented in this thesis is based on the Node Activation Polling Access (NAPA), Virtual Slot (VSLOT), and message based slot assignment algorithms. To evaluate the performance of the designed self-organized TDMA protocol over the preprogramming TDMA protocol, the simulation models for both protocols were implemented and simulated with NS-2 under the specific study scenarios. The results show that the self-organized TDMA protocol offers more flexibility and higher performance than the preprogramming TDMA protocol. In addition, the aspects of stability and security for the self-organized TDMA protocol were discussed. The overall conclusion is that the self-organized TDMA protocol could be a viable alternative for a future TDL system.

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Hebley, Matthew G. "Generalised linear diversity receivers for wireless TDMA systems." Thesis, University of Canterbury. Electrical and Electronic Engineering, 1997. http://hdl.handle.net/10092/8414.

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The continual demand for increased mobile radio capacity prompts continued development of new technology to increase system performance. This thesis presents an investigation of the performance of a generalised linear diversity receiver, as an implementable approximation to the optimum diversity receiver. The receiver utilises space, or antenna, diversity combining to combat the effects of multipath fading experienced in the mobile channel. The receiver is intended for coherent reception of linearly modulated wideband time division multiple access (TDMA) digital transmissions. The receiver structure is also restricted to the linear case. Two major analyses are undertaken in this thesis: the performance of the diversity receiver with finite-length fractionally-spaced branch equalisers, assuming ideal channel-state-information and synchronisation; and the performance of a carrier frequency offset recovery algorithm, assuming only knowledge of the channel autocorrelation function, and burst synchronisation. This thesis presents a general time-varying frequency-selective multipath Rayleigh fading model. The system model includes non-white, non-Gaussian co-channel interferers as well as non-white, but Gaussian co-channel interferers. However, adjacent channel interference is not modelled. Simulation results are presented for the best possible performance (with ideal channel-state-information) of the diversity receiver, showing the effects of diversity and finite equaliser length, and are compared to results for the optimum linear receiver. The results show that increased diversity is very powerful in improving the performance of the receiver, and that the equaliser lengths can be quite short (e. g., 10 taps) and the receiver will still perform close to the optimum. The receiver is shown to be more capable of combating non-Gaussian co-channel interference than Gaussian (or noise-like) interference. The performance of the carrier frequency offset estimator is also determined by simulation. It is found that in most cases, doubling the diversity reduces the error standard deviation by a factor of two or more. The estimator is found to be relatively insensitive to symbol timing, channel delay spread, frequency offset and signal-to-noise ratio, especially with high diversity.

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Khan, Luqman F. "Real-Time Communication with TDMA on Distributed Systems." Thesis, California State University, Long Beach, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=10978912.

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A CrazyRadio is a 2.4GHZ usb bluetooth dongle and a Crazyflie is a programmable quadrotor used by researchers in the field of distributed computing. A Crazyflie is controlled remotely from a computer or a smartphone through a Crazyradio. However the communication protocol on the CrazyRadio can communicate only with one Crazyflie after pairing, therefore implementing a swarm requires many changes which are prone to failures. This thesis proposes a communication protocol for distributed and highly dynamic systems. The proposed protocol is a combination of two communication protocols: Slotted-Aloha and time division multiple access (TDMA).The implementation of the proposed protocol is done on Crazyradios and Crazyflies. With the proposed protocol a Crazyradio communicates with multiple Crazyradios and Crazyflies. Communication between Crazyradios facilitates realtime data transfer between any type of bots connected to these Crazyradios, adding towards the implementation of swarms of robots.

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MacDonald, Robert J. (Robert James) Carleton University Dissertation Information and Systems Science. ""Performance analysis of two hop" "CSMA_CD/TDMA networks." Ottawa, 1989.

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Persson, Anders. "A TDMA Module for Waterborne Communication with Focus on Clock Synchronization." Thesis, Linköpings universitet, Programvara och system, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-103028.

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This bachelor thesis has been carried out at the company Didamus which is located in Mjärdevi, Linköping. The company is currently developing a dive-console which aims to take the scuba diving experience to a whole new level and also to make scuba diving more secure. An assembly of scuba divers that can communicate with each other during a dive session might be the difference between life and death. Many seas around the world have muddy water which means poor visibility. In each situation a computer providing a scuba diver with information about others connected to the network, hazardous accidents can possibly be avoided. The network itself consist of 10 nodes that need a network protocol which provides stability and reliability for every participant. The nodes themselves have a distributed responsibility to make the network reliable. The type of network implemented was a regular Time Division Multiple Access (TDMA) network where different nodes were given permission to access the medium in different instances of time. A global reference of time is always needed in a TDMA network to make it function properly. In a typical TDMA network a GPS-service gives each and every node information about the global time. Unfortunately, GPS-services do not work well in water so a Master-Slave method was used instead. The master provides the rest of the nodes in the network with a global time reference. After a successful reception of a global time reference, the slave will be granted access to the network. The communication between the nodes is based on ultrasonic waves propagating in the water. The velocity of ultrasonic waves in water is only 1500 meters per second, explained in Discovery of Sound in the Sea by University of Rhode Island, which is a relatively slow signal speed. With the slow velocity taken into account an efficient TDMA protocol was developed, to perform communication under water.

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Dyberg, Karin, and Linda Farman. "Spatial TDMA in Ad Hoc Networks with Antenna Arrays." Thesis, Linköping University, Department of Science and Technology, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1104.

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In modern military operations the requirements of transmitting large amounts of information have increased substantially during the last decade. This increases the demand for high-capacity radio networks. It is also very important that military decisions are made on recent and correct information and this implies that low and known delays are required. The existing military radio ommunications, within the Swedish army, do not meet the requirements for capacity and delay.

We have investigated how the capacity and average delay can be improved in an Ad Hoc network with STDMA by using antenna arrays. The study is based on different antenna combinations consistingof single isotropic antenna element, beam steering and adaptive beamforming. We have also studied how the number of antenna elements, the terrain, and an increased connectivity due to the antenna arrays_affects the performance measurements.

The study shows that the capacity is improved with up to 1200%, and the average delays are decreased when using antenna arrays instead of single isotropic antenna elements. Depending on the beamforming combination used the capacity gain and average delay reduction will differ. The way of using the antenna array also affects the capacity gain and average delay. The capacity gain is higher when the antenna array is used not only to suppress and decrease interferences, but also to increase the connectivity.

The study also shows that the capacity gain is higher when using more antenna elements for a network with a high number of links, than with fewer. The benefit from antenna arrays is higher in a flat terrain than in a rough.

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Micic, Aleksandar. "Initialization protocols for TDMA in single-hop wireless network." Thesis, University of Ottawa (Canada), 2003. http://hdl.handle.net/10393/26523.

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Although collision free TDMA schemes have been proposed and used for more than two decades, an important ingredient of these schemes, the initialization of stations (that is, assigning ID numbers 1,2,...,N) was not investigated until recently. In this thesis, we propose several new randomized and deterministic initialization methods, and measure the performance of these new and some known methods. The main contributions of this thesis are new randomized hybrid algorithms for the cases of known and unknown number of users. Performance of these algorithms was evaluated by comparing it with improved versions of existing algorithms, and an improvement from e·N to approximately 2.2·N was obtained. We also proposed the first deterministic initialization algorithms, and showed that they have comparable performance to the corresponding randomized algorithms. The initialization algorithms are then incorporated into collision free TDMA schemes, which take into account the dynamic nature of network and dynamic bandwidth requirements.

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Cui, Qin. "TDMA-based Routing Protocol in Industrial Wireless Sensor Networks." Thesis, Mittuniversitetet, Avdelningen för informations- och kommunikationssystem, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-19748.

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Stevens, David Story. "TDMA slot allocation strategies for mobile packet radio networks." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/9190.

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Chaaban, Mohamad Radi. "Performance evaluation of a TDMA digital mobile radio system." Thesis, University of Liverpool, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358944.

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Oliveira, Carlos Henrique Rodrigues de. "Codificação de canal alternativa para o sistema movel TDMA." [s.n.], 2000. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259804.

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Orientador: Renato Baldini Filho
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: Este trabalho apresenta propostas alternativas de codificação de canal para o sistema móvel TDMAjI8-136. As comparações destes sistemas de codificação de bloco com o contido na recomendação 18-136 são feitas através de curvas de desempenho (BER x 8NR) obtidas por simulação computacional. Os sistemas são analisados em canais AWGN com e sem desvanecimento Rayleigh. A decodificação por treliça de códigos de bloco é realizada com decisão abrupta e suave
Abstract: This work presents alternative channel encoding schemes to the TDMAj1S-136 mobile system. The comparisons of these block code systems with that contained in the 1S-136 Recommendation have been made by computer simulation in terms of the Bit Error Rate (BER) as a function ofthe Signal-to-Noise Ratio (SNR). The system performance is evaluated in AWGN channel with and without Rayleigh fading. The trellis decoding of block codes is made with hard and soft-decision
Mestrado
Mestre em Engenharia Elétrica

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Louis, Lee Winnie. "Flexible-schedule-based TDMA protocols for supporting fault-tolerance, on-demand TDMA slot transfer, and peer-to-peer communication in wireless sensor networks." University of Western Australia. School of Computer Science and Software Engineering, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0028.

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[Truncated abstract] This thesis develops a scheduled protocol (time division multiple access, TDMA) called flexible-schedule-based TDMA Protocol (FlexiTP), to address the problem of providing end-to-end guarantees on data delivery, whilst also respecting severe resource constraints of wireless sensor networks. FlexiTP achieves this balance through a distributed, synchronised, and loose slot structure in which sensor nodes can build, modify, or extend their schedules based on their local information. In FlexiTP, it is not necessary to predetermine the number of slots required for a network. FlexiTP's local repair scheme allows nodes to adjust their schedules dynamically and autonomously to recover from node and communication faults. Hence, it maintains a reliable and selforganising multihop network. Most sensor network protocols designed for data gathering applications implicitly assume a periodic rate of data collection from all nodes in the network to the base station. However, nodes may want to report their data more rapidly or slowly depending on the significance and importance of their data to the end-user. The problem is that traditional TDMA-based protocols are not flexible to changes in traffic patterns because of their rigid slot structure schemes. This thesis aims to solve this problem by developing an ondemand TDMA slot transfer method that leverages the flexible-slot structure algorithm of FlexiTP to transfer time slots from one part of the network to another part. ... While these communication patterns are sufficient for monitoring applications, individual sensor nodes may need to send their data to multiple destination nodes across the network in order to execute a distributed cooperative-function based on their local environment. This peer-to-peer communication pattern makes sensor networks more reactive to triggers from the environment. This thesis attempts to solve the problem of lack of peer-to-peer communication in the design of a TDMA-driven protocol by extending the idea of on-demand TDMA slot transfer method to allow each sensor node in the network to claim extra time slots to communicate with any other nodes (peers) in the network, without going through the base station. Nodes in the network may have different priorities of data because of event-triggering sensor readings or various types of sensor readings (e.g., light, temperature, and humidity) they provide. When nodes with high priority packets increase the frequency of their data collections, the network bandwidth may be dominated by these nodes. It is desirable to allow nodes with low priority packets to aggregate their packets and so enabling these nodes to send their data to the base station under the current available network bandwidth. This thesis proposes an on-demand data aggregation algorithm that enables sensor nodes to perform an in-network-aggregation based on their current sensing requirements and network capacity constraints. In summary, this thesis describes the design, implementation, and evaluation of protocols for wireless sensor networks that focus on achieving energy-efficiency, provisioning performance assurances, and supporting reactivity and adaptability in constantly changing environment.

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Karam, Fouad G. "An optimal TDMA slot assignment in multibeam packet satellite systems." Thesis, University of Ottawa (Canada), 1986. http://hdl.handle.net/10393/5038.

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Shad, Faisal. "SDMA/TDMA dynamic slot assignment using a smart antenna basestation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0030/NQ66294.pdf.

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Ren, Tiegeng. "Graph coloring algorithms for TDMA scheduling in wireless sensor networks /." View online ; access limited to URI, 2007. http://0-digitalcommons.uri.edu.helin.uri.edu/dissertations/AAI3298376.

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32

Pons, Puig Juan Antonio. "Application of link adaptation to evolved TDMA mobile communications systems." Thesis, University of Strathclyde, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273351.

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Blogh, Jonathan S. "Adaptive modulation and adaptive antenna assisted wireless TDMA/CDMA networks." Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341647.

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PINHEIRO, ANA LUCIA DE ALBUQUERQUE. "MULTIPLE ACCESS PROTOCOLS FOR TDMA TECHNOLOGY IN MÓBILE COMMUNICATIONS SYSTEMS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1996. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=8694@1.

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O rápido desenvolvimento tecnológico que ocorreu na área de comunicações móveis e o surpreendente interesse por parte dos usuários geraram um crescimento da demanda maior que o esperado. A necessidade de atender essa demanda e de suportar novos serviços como áudio, vídeo e multimídia, vem motivando o estudo de novas tecnologias. Atualmente, um dos objetivos principais é o aumento da capacidade da interface rádio. Visando este objetivo, diversos métodos de acesso vêm sendo propostos. Neste trabalho será feita uma análise de três protocolos de acesso proposta para tecnologia TDMA: o PRMA (Packet Reservation Multiple Access), o RAMA (Resource Auction Multiple Access). Resultados numéricos comparando o desempenho dos protocolos RAMA e TRAMA não estavam disponíveis na literatura e serão apresentados. Baseando-se nestes resultados será proposta uma variação do RAMA, o F-RAMA (Fair Resource Auction Multiple Access). O desempenho do protocolo para transmissão de voz bem como a comparação com os outros protocolos serão apresentados. Será visto que o F-RAMA é um excelente candidato à transmissão de voz e bastante promissor para a tecnologia multimídia no ambiente móvel celular.
The fast technological development that occurred in the mobile communications sector and the outstanding interest showed by the users resulted in na unexpected huge demand. The need to sypply this demand and to support new services such as audio, video and multimedia have motivated the study of new technologies. Nowadays, one of the greatest challenge is to increase the radio interface capacity. To meet this goal many access methods have been proposed. This work will analyse three access protocols proposed to TDMA technology: PRMA ( packet Reservation Multiple Access), RAMA (Resource Auction Multiple Access) and TRAMA ( Tree-search Resource Auction Multiple Acess), Numerical results comparing RAMA and TRAMA that were so far unavailable in the literature will be presented here. Based upon these results a variation of RAMA, F-RAMA ( Fair Resource Auction Multiple Access), will be proposed. The protocol perfomance for voice transmission and a comparison among the three will also be presented herein. The effect of the multimedia transmission over F-RAMA will be discussed. It will be show that F-RAMA is an excellent candidate for voice trasmission and a promising candidate for multimedia transmission in the mobile communication environment.

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NEVES, MARCIO FRITSCH TOROS. "PERFORMANCE OF MULTIPLE ACCESS TDMA PROTOCOLS IN SATELLITE ATM NETWORKS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1997. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=8868@1.

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Com o objetivo de prover acesso global ao mundo da informação, as comunicações via satélite desempenham um papel fundamental, possibilitando o acesso de serviços de faixa larga em áreas onde a infra-estrutura terrestre não permite. Este trabalho apresenta uma caracterização destas aplicações potenciais para redes ATM via satélite, descrevendo os problemas e as limitações que ainda precisam ser superados, assim como as soluções que já foram sugeridas. Entre estes problemas, está o desenvolvimento de protocolos de múltiplo acesso que possibilitem a utilização eficiente do segmento espacial e, ao mesmo tempo, garanta a qualidade do serviço. Os protocolos de múltiplo acesso tradicionais não são adequados para redes com múltiplos serviços, como se espera num ambiente de faixa larga, visto que foram desenvolvidos para redes com um determinado tipo de aplicação. Desta forma, é necessário realizar uma adaptação destas técnicas convencionais, para esta nova realidade, pois através de protocolos de múltiplos acesso eficiente, será possível obter ganhos consideráveis nos recursos de segmento espacial, cada vez mais escassos e, conseqüentemente, caros. Para verificar em mais detalhes este problema, descreveremos três protocolos propostos para múltiplo acesso em redes ATM via satélite, todas eles baseados na técnica de método de acesso por divisão do tempo (ADTMA). O desempenho destes protocolos é analisado, através de simulação, comparando-se as vantagens e desvantagens de cada um.
In order to provide global Access to the world of information, the satellite communications play a key rolo, making possible the Access of broadband services to areas where the terrestrial infrastructure doesn´t allow. This work shows a characterization of the potencials applications to the satellite ATM networks, making a description of the problems and limitations that need to be overcome, as well as the solutions that have been suggested. Among thesse problems, we have the development of multiple access protocols that allow an efficient utilization of space segment and, at same time, guarantee the quality of service. The traditionals multiples access protocols are not well suitable to multiple service networks, as we hope in a broadband environment, since they were created to networks with a specific application. So, it´s necessary to make an adaptation in these conventionals technics to this new reality, because through efficients multiple access protocols, will be possible to have considerable gains in space segment`s resources, more and more rare and, consequantly, expensive. To verify in more details this problem, we describe three protocols suggested to provide multiple access in satellite ATM networks, all of them based on the technic of time division multiple access (TDMA). The performance analysis of these protocols is done, through simulations, confronting the advantages and disadvantages of each one.

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Williams, Lauren M. "Fast Chirped Signals for a TDMA Ultrasonic Indoor Positioning System." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2150.

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In this paper, a new concept for ultrasonic indoor positioning based on instantaneous frequency of ultrasonic signals is presented. Nonlinear phase characteristics of ultrasonic transducers introduce a frequency deviation in ultrasonic signals. By sweeping at very fast rates, a large spike in the deviation is introduced. The artefacts observable in instantaneous frequency estimations are highly localized and present an opportunity for accurate frequency detection. In order to be useful, the artefacts need to take place within the pulse and have sufficient magnitude for accurate processing. The system consists of a transducer transmitter and receiver pair, which have a center frequency of 40kHz and a bandwidth of 460Hz. In order to incorporate more transmitters, a time-division multiple access (TDMA) scheme is applied to ensure orthogonality of signals. The concept includes four ultrasonic transmitters and a single receiver, which can uniquely identify each transmitter by a distinct signal sweep. Linear chirp signals are used to form narrow pulses and ensure no interference in the TDMA scheme. The received signal is amplified and passed through a phase-locked loop (PLL) to detect the chirp signals. Accurate instantaneous frequency detection can be done on the voltage-controlled oscillator (VCO) of the PLL, which has a narrower bandwidth than the overall signal sweep. The instantaneous frequency estimation methods are largely explored in this work and consider two methods: the Hilbert transform and a zero-crossings method. This work highlights some of the advantages and disadvantages of both methods. Time of flight (ToF) in this system can ultimately be obtained by considering the instantaneous frequency estimations and the time for one particular frequency to be transmitted and received.

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Sapru, Arun. "Investigative Study on Frame Synchronization for TDMA Data Link Design." University of Toledo / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1279298966.

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Oliveira, Roberto Massi de. "A Cooperative MAC Protocol to Improve the Performance of In-Home Broadband PLC Systems." Universidade Federal de Juiz de Fora, 2015. https://repositorio.ufjf.br/jspui/handle/ufjf/64.

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Submitted by Renata Lopes (renatasil82@gmail.com) on 2015-12-01T12:45:13Z No. of bitstreams: 1 robertomussideoliveira.pdf: 1293292 bytes, checksum: 78c6c9fd9415c0b3990a1aaf55b842a2 (MD5)
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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Nesse trabalho, discutimos o uso de protocolos de coopera¸c˜ao na subcamada de controle de acesso ao meio (CMAC) para reduzir a taxa de perda de pacote e aumentar o goodput em um sistema de comunica¸c˜ao banda larga via rede el´etrica (PLC) de ambientes residenciais. Para apoiar essa discuss˜ao, n´os, pela primeira vez, apresentamos uma an´alise estat´ıstica da taxa de erro de pacote (PER) de canais PLC residenciais a partir de dados medidos em um modelo com um ´unico relay. Adicionalmente, n´os esbo¸camos um simples protocolo CMAC capaz de explorar a diversidade oferecida por uma rede el´etrica dom´estica. Usando esse protocolo, nosso objetivo ´e mostrar o impacto da varia¸c˜ao da largura de banda, da varia¸c˜ao da PER e da posi¸c˜ao relativa do relay no desempenho do sistema. Sendo assim, n´os mostramos que a taxa de perda de pacote e o goodput melhoram quando a largura de banda de frequˆencia aumenta. Al´em disso, resultados mostram que a coopera¸c˜ao na camada de enlace n˜ao oferece vantagens caso os valores de PER do enlace direto e do enlace intermediado pelo relay sejam muito altos ou muito baixos. N´os tamb´em notamos que as melhorias estudadas dependem da posi¸c˜ao do n´o relay em rela¸c˜ao ao n´o fonte e ao n´o destino (i.e., notamos melhoras na rede nos casos em que o relay estava situado pr´oximo `a fonte e no meio do caminho entre a fonte e o destino). Finalmente, uma compara¸c˜ao entre os esquemas de acesso m´ultiplo por divis˜ao de frequˆencias ortogonais - acesso m´ultiplo por divis˜ao de tempo (OFDMA-TDMA) e acesso m´ultiplo por divis˜ao de tempo - multiplexa¸c˜ao por divis˜ao ortogonal de frequˆencia (TDMA-OFDM) mostra que o simples protocolo CMAC ´e mais eficaz quando usado juntamente com o primeiro esquema do que com o ´ultimo. Em suma, a nossa contribui¸c˜ao ´e dividida em duas etapas: primeiramente, desenvolvemos um simples protocolo MAC de coopera¸c˜ao que traz melhorias de desempenho na rede quando comparado com um sistema sem a coopera¸c˜ao; em segundo lugar, n´os realizamos uma an´alise sistem´atica de diferentes cen´arios, mostrando os benef´ıcios e limita¸c˜oes da coopera¸c˜ao na camada de enlace de redes PLC.
In this work, we discuss the use of cooperative medium access control (CMAC) protocols to reduce packet loss rate and to improve goodput of in-home broadband power line communication (PLC) systems. To support this discussion, we, for the first time, present a statistical packet error rate (PER) analysis of measured in-home PLC channels by adopting a single relay model. Additionally, we outline a simple CMAC protocol that is capable of exploiting the diversity offered by in-home electric power grids. Using this protocol, we aim to show the impact of bandwidth variation, PER variation and of relative relay location on system performance. Thus, we show that packet loss rate and goodput improve when frequency bandwidth increases. Also, results show that cooperation at the link layer does not offer advantages if the PER values of direct and relayed links are very high or very low. Furthermore, we note that the improvements depend on the location of the node relay in relation to the nodes source and the destination (i.e., network improves if the relay is located near the source or in the midway between the source and the destination). Finally, a comparison between orthogonal frequency division multiple access - time division multiple access (OFDMA-TDMA) and time division multiple access - orthogonal frequency division multiplexing (TDMA-OFDM) schemes show that the simple CMAC protocol is more effective when it is used together with the former scheme than the latter.

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39

Ємельянов, В. В., and В. В. Томак. "Ємність стільника мережі стільникового мобільного звя’зку з кодовим розділенням каналів." Thesis, ФОП Петров В. В, 2021. https://openarchive.nure.ua/handle/document/18666.

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Метою доповіді є розгляд методів розрахунку кількості активних абонентів в стільнику (ємність стільника), що описані. У доповіді відмічено, що описаний метод при визначенні ємності стіль- ника не враховує реальні фактори, що впливають на її величину, а саме, секторність стільника, коефіцієнт підсилення тощо.

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40

Ciocco, Timothy Michael. "A comparison study of CDMA versus TDMA/FDMA LEO satellite systems." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1996. http://handle.dtic.mil/100.2/ADA307158.

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Thesis (M.S. in Electrical Engineering) Naval Postgraduate School, March 1996.
Thesis advisor(s): Paul H. Moose, R. Clark Robertson. "March 1996." Includes bibliographical references. Also available online.

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41

Ichikawa, Naoki, Masaaki Katayama, Hiraku Okada, Takaya Yamazato, and Akira Ogawa. "Comparison of CDMA and FDMA/TDMA in non-GEO Satellite Systems." IEEE, 2001. http://hdl.handle.net/2237/7750.

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42

Tunç, Muharrem Ali. "Performance Evaluation of a TDMA MAC Protocol in Airborne Telemetry Networks." International Foundation for Telemetering, 2010. http://hdl.handle.net/10150/604270.

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ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California
Emerging airborne telemetry networks are going beyond traditional point-to-point communication. The iNET telemetry architecture uses a TDMA MAC with relay nodes that enable multi-hop communication. We analyze the performance of the iNET TDMA MAC protocol with respect to various parameters such as number of nodes, flight range, number of relays, and number of hops via mathematical modeling. We also discuss the role of cross-layer optimizations with the AeroNP, AeroRP, and AeroTP aeronautical protocols.

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Despins, Charles L. B. (Charles Louis Bertrand) Carleton University Dissertation Engineering Electrical. "Coding and optimum baseband combining for wideband TDMA indoor wireless channels." Ottawa, 1991.

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44

Meyer, Nicholas Karl. "Water uptake of aerosols with a focus on seeded aerosols and instrumentation techniques." Thesis, Queensland University of Technology, 2008. https://eprints.qut.edu.au/26361/1/Nicholas_Meyer_Thesis.pdf.

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This thesis focuses on the volatile and hygroscopic properties of mixed aerosol species. In particular, the influence organic species of varying solubility have upon seed aerosols. Aerosol studies were conducted at the Paul Scherrer Institut Laboratory for Atmospheric Chemistry (PSI-LAC, Villigen, Switzerland) and at the Queensland University of Technology International Laboratory for Air Quality and Health (QUT-ILAQH, Brisbane, Australia). The primary measurement tool employed in this program was the Volatilisation and Hygroscopicity Tandem Differential Mobility Analyser (VHTDMA - Johnson et al. 2004). This system was initially developed at QUT within the ILAQH and was completely re-developed as part of this project (see Section 1.4 for a description of this process). The new VHTDMA was deployed to the PSI-LAC where an analysis of the volatile and hygroscopic properties of ammonium sulphate seeds coated with organic species formed from the photo-oxidation of á-pinene was conducted. This investigation was driven by a desire to understand the influence of atmospherically prevalent organics upon water uptake by material with cloud forming capabilities. Of particular note from this campaign were observed influences of partially soluble organic coatings upon inorganic ammonium sulphate seeds above and below their deliquescence relative humidity (DRH). Above the DRH of the seed increasing the volume fraction of the organic component was shown to reduce the water uptake of the mixed particle. Below the DRH the organic was shown to activate the water uptake of the seed. This was the first time this effect had been observed for á-pinene derived SOA. In contrast with the simulated aerosols generated at the PSI-LAC a case study of the volatile and hygroscopic properties of diesel emissions was undertaken. During this stage of the project ternary nucleation was shown, for the first time, to be one of the processes involved in formation of diesel particulate matter. Furthermore, these particles were shown to be coated with a volatile hydrophobic material which prevented the water uptake of the highly hygroscopic material below. This result was a first and indicated that previous studies into the hygroscopicity of diesel emission had erroneously reported the particles to be hydrophobic. Both of these results contradict the previously upheld Zdanovksii-Stokes-Robinson (ZSR) additive rule for water uptake by mixed species. This is an important contribution as it adds to the weight of evidence that limits the validity of this rule.

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45

Meyer, Nicholas Karl. "Water uptake of aerosols with a focus on seeded aerosols and instrumentation techniques." Queensland University of Technology, 2008. http://eprints.qut.edu.au/26361/.

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This thesis focuses on the volatile and hygroscopic properties of mixed aerosol species. In particular, the influence organic species of varying solubility have upon seed aerosols. Aerosol studies were conducted at the Paul Scherrer Institut Laboratory for Atmospheric Chemistry (PSI-LAC, Villigen, Switzerland) and at the Queensland University of Technology International Laboratory for Air Quality and Health (QUT-ILAQH, Brisbane, Australia). The primary measurement tool employed in this program was the Volatilisation and Hygroscopicity Tandem Differential Mobility Analyser (VHTDMA - Johnson et al. 2004). This system was initially developed at QUT within the ILAQH and was completely re-developed as part of this project (see Section 1.4 for a description of this process). The new VHTDMA was deployed to the PSI-LAC where an analysis of the volatile and hygroscopic properties of ammonium sulphate seeds coated with organic species formed from the photo-oxidation of á-pinene was conducted. This investigation was driven by a desire to understand the influence of atmospherically prevalent organics upon water uptake by material with cloud forming capabilities. Of particular note from this campaign were observed influences of partially soluble organic coatings upon inorganic ammonium sulphate seeds above and below their deliquescence relative humidity (DRH). Above the DRH of the seed increasing the volume fraction of the organic component was shown to reduce the water uptake of the mixed particle. Below the DRH the organic was shown to activate the water uptake of the seed. This was the first time this effect had been observed for á-pinene derived SOA. In contrast with the simulated aerosols generated at the PSI-LAC a case study of the volatile and hygroscopic properties of diesel emissions was undertaken. During this stage of the project ternary nucleation was shown, for the first time, to be one of the processes involved in formation of diesel particulate matter. Furthermore, these particles were shown to be coated with a volatile hydrophobic material which prevented the water uptake of the highly hygroscopic material below. This result was a first and indicated that previous studies into the hygroscopicity of diesel emission had erroneously reported the particles to be hydrophobic. Both of these results contradict the previously upheld Zdanovksii-Stokes-Robinson (ZSR) additive rule for water uptake by mixed species. This is an important contribution as it adds to the weight of evidence that limits the validity of this rule.

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46

Weckerle, Martin. "Utilization of correlation matrices in adaptive array processors for time slotted CDMA uplinks." Kaiserslautern : Univ, 2002. http://deposit.d-nb.de/cgi-bin/dokserv?idn=967819091.

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Chowdhury, Moyamer, and Aminul Alam. "Study Comparison of WCDMA and OFDM." Thesis, Blekinge Tekniska Högskola, Avdelningen för telekommunikationssystem, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-1363.

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Wideband Code Division Multiple Access (WCDMA) is one of the main technologies for the implementation of third-generation (3G) cellular systems. It is based on radio access technique proposed by ETSI Alpha group and the specifications was finalised 1999. WCDMA is also known as UMTS and has been adopted as a standard by the ITU under the name “IMT-2000 direct spread”. The implementation of WCDMA will be a technical challenge because of its complexity and versatility. The complexity of WCDMA systems can be viewed from different angles: the complexity of each single algorithm, the complexity of the overall system and the computational complexity of a receiver. In WCDMA interface different users can simultaneously transmit at different data rates and data rates can even vary in time. WCDMA increases data transmission rates in GSM systems by using the CDMA air interface instead of TDMA. WCDMA is based on CDMA and is the technology used in UMTS. WCDMA is the dominating 3G technology, providing higher capacity for voice and data and higher data rates. The gradual evolution from today's systems is driven by demand for capacity, which is required by new and faster data based mobile services. WCDMA enables better use of available spectrum and more cost-efficient network solutions. The operator can gradually evolve from GSM to WCDMA, protecting investments by re-using the GSM core network and 2G/2.5G services. Orthogonal Frequency Division Multiplexing (OFDM) - technique for increasing the amount of information that can be carried over a wireless network uses an FDM modulation technique for transmitting large amounts of digital data over a radio wave. OFDM works by splitting the radio signal into multiple smaller sub-signals that are then transmitted simultaneously at different frequencies to the receiver. OFDM reduces the amount of crosstalk in signal transmissions. 802.11a WLAN, 802.16 and WiMAX technologies use OFDM. It's also used in the ETSI's HiperLAN/2 standard. In addition, Japan's Mobile Multimedia Access Communications (MMAC) WLAN broadband mobile technology uses OFDM. In frequency-division multiplexing, multiple signals, or carriers, are sent simultaneously over different frequencies between two points. However, FDM has an inherent problem: Wireless signals can travel multiple paths from transmitter to receiver (by bouncing off buildings, mountains and even passing airplanes); receivers can have trouble sorting all the resulting data out. Orthogonal FDM deals with this multipath problem by splitting carriers into smaller subcarriers, and then broadcasting those simultaneously. This reduces multipath distortion and reduces RF interference allowing for greater throughput. In this paper we have discussed about these two methods of third generation radio transmission system which are WCDMA and OFDM with various aspects. In between these two radio transmission technique, a better choice will be investigated.

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O'Connell, Ray, and Lyle Webster. "Telemetry Network System (TmNS) Link Management Modeling and Simulation." International Foundation for Telemetering, 2011. http://hdl.handle.net/10150/595634.

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ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada
The TmNS system employs a novel channel access approach to achieve efficient use of the available spectrum while still providing a reliable bi-directional telemetry link. At the heart of this process is the Link Manager which performs real time adjustments to the transmission windows of radios as it senses changes in network connectivity, transmit queue loading, and network management input. Dynamic network capacity control based on radio queue loading is presented as an example of an operation to be verified by modeling and simulation.

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49

Mai, Wilson W. Q. "Timing and carrier phase recovery for a burst ATM satellite TDMA channel." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0002/MQ45286.pdf.

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Grant, Stephen James. "Increased capacity for TDMA cellular systems through joint detection with diversity arrays." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0009/NQ61645.pdf.

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Dissertations / Theses on the topic 'TDMA'

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