| Today, the need for increased mobility puts an additional emphasis on wireless communications. Wireless technologies bring several obvious advantages in our everyday activity, like: mobility, scalability, ease of installation, reliability, affordability. The ubiquitous use of wireless communications will represent an important step ahead toward the final goal of communications: the delivery of any amount of information, anywhere, anytime to anyone is entitled to.; This thesis has two distinctive parts: (1) In the first part I make a presentation of the main steps in the evolution of wireless communications. Both wireless telecommunications and data communications are analyzed. A particular emphasis is put on the merge of the 3 types of wireless communications and the emerging multiservice networks. (2) In the second part of the thesis I modeled and simulated different types of wireless multiservice networks, using OPNET simulation software and I explored the performance of these type of networks.; I modeled three types of wireless multriservice networks: ad-hoc, infrastructure, and wireline routed networks. As multimedia communication, digitized and packetized voice is generated.; The study gives answers specific questions for wireless multimedia communications, like: (1) as physical layer, is Direct Sequencing or Frequency Hopping more suitable; (2) as voice codec, is G.711 or G.729 more suitable; (3) what is the maximum number of wireless users the wireless network can accept without degrading the quality of voice transmission; (4) what technologies and in what degree, can solve quality of service in a wireless multimedia network.; The research can be continued with new challenges like: (1) measuring the impact of different combinations of data transport over voice transport; (2) studying the impact of new multimedia applications like digitized and packetized video transmission, over wireless networks. |
