Made available in DSpace on 2016-04-04T18:31:23Z (GMT). No. of bitstreams: 1 KERLLA DE SOUZA LUZ OLIVEIRA.pdf: 1568205 bytes, checksum: bce8e961721a4346ba548c8f58ba336a (MD5) Previous issue date: 2008-05-29 / This work evaluates the coverage of a WMAN (Wireless Metropolitan Area Network), with characteristics of a system WiMAX (Worldwide Interoperability will be Microwave Access) operating in 5.8GHz, in accordance with the used modulation. In order to reach this goal, predictions of field covering were used and measurements were made. The modulation of a adaptative antenna depends on the value of the received power and the attenuation of this power varies according to the region where the signal propagates. In this work the distribution of the modulation in the coverage area was evaluated using the Shadowing model to describe the attenuation of the signal in accordance with the considered environment. As a result, it could be observed the association of areas with two types of possible modulation due to the overlap of modulation bands generated by the standard deviation of the signal medium value. / Este trabalho avalia a cobertura de uma WMAN (Wireless Metropolitan Area Network), com caracter?sticas de um sistema WiMAX (Worldwide Interoperability for Microwave Access) operando em 5.8GHz, de acordo com a modula??o utilizada. Para tanto, empregaram-se tanto predi??es de cobertura quanto medidas de campo. A modula??o de uma antena depende do valor da pot?ncia recebida e a atenua??o desta pot?ncia varia de acordo com a regi?o por onde o sinal se propaga. Neste trabalho foi avaliada a mudan?a da modula??o dentro da ?rea de cobertura, utilizando-se o modelo de Shadowing para descrever a atenua??o do sinal de acordo com o ambiente considerado. Como resultado p?de-se observar a associa??o de ?reas com dois tipos de modula??es poss?veis, devido ?s faixas de sobreposi??o de modula??o geradas pelo desvio padr?o do valor m?dio do sinal.

Made available in DSpace on 2016-04-04T18:31:25Z (GMT). No. of bitstreams: 1 Marcia Maria Savoine.pdf: 2175715 bytes, checksum: 355bcfef34d422002fc47ef44d62e191 (MD5) Previous issue date: 2009-02-06 / This work presents the comparison made through simulations of discreet events, accomplished with the software ARENA, the techniques of Time Division Duplex (TDD) and Frequency Division Duplex (FDD). Techniques present in the pattern IEEE 802.16 and used by WiMAX in the bi-directional channels of uplink and downlink. The simulation model considered in the line of arrival of the services the concept FIFO (First-In, First-Out) and the simulations were accomplished considering five applications (Streaming, Download, Web, E-mail and Small-Transaction) for downlink and uplink. The number of channels in the Base Station varied from 4 to 60, with a throughput of 600 kbps. The regarded efficiency parameter was the minimum number of channels necessary in each one of the standard channels. The simulations were accomplished in three sceneries., In the first scenery it was considered the same profile of traffic for downlink and uplink, in the second scenery a traffic of downlink 2, 5, 10 and 15 times larger than the one of uplink. And, in the third scenery it was considered different proportions of traffics varying from 2 to 5 times more, 5 to 10 times more and from 10 to 15 times more. The analyses were done considering as efficiency parameter the converge of the waiting time of the users. ,It was verified that in asymmetric data traffic, the TDD technique was more efficient and there were spectrum idleness in the FDD technique. / Este trabalho apresenta a compara??o efetuada por meio de simula??es de eventos discretos, realizadas com o software ARENA, das t?cnicas de Duplexa??o por Divis?o no Tempo (TDD) e Duplexa??o por Divis?o da Freq??ncia (FDD), t?cnicas presentes no padr?o IEEE 802.16 e utilizadas pelo WiMAX nos canais bidirecionais de uplink e downlink. O modelo de simula??o considerou na fila de chegada dos servi?os o conceito FIFO (First-In, First-Out) e as simula??es foram realizadas considerando cinco aplica??es (Streaming, Download, Web, E-mail e Small-Transaction) para downlink e uplink. O n?mero de canais na Base Station variou de 4 a 60, com um throughput de 600 kbps. O par?metro de efici?ncia considerado foi o n?mero m?nimo de canais necess?rio em cada um dos canais padr?es. As simula??es foram realizadas em tr?s cen?rios, sendo que, no primeiro cen?rio se considerou o mesmo perfil de tr?fego para downlink e uplink, no segundo cen?rio com tr?fego de downlink 2, 5, 10 e 15 vezes maior que o de uplink. E, no terceiro cen?rio com propor??es variadas de tr?fegos variando de 2 a 5 vezes mais, 5 a 10 vezes mais e de 10 a 15 vezes mais. Realizadas as simula??es foram feitas as an?lises dos desempenhos, tomando como par?metro de efici?ncia a taxa de chegada e o tempo de espera do usu?rio perante aplica??es t?picas utilizadas na tecnologia de banda licenciada WiMAX, que segue este padr?o. A an?lise efetuada permitiu identificar, dada estas condi??es de tr?fego, qual das t?cnicas seria a mais indicada. Constatou-se ainda que em tr?fego de dados assim?tricos a t?cnica TDD se apresentou mais eficiente e, observou-se existir ociosidade de espectro na t?cnica FDD.