In this thesis we have focused in the wireless environment and how to run voice application over it. Conducive environment that makes it possible for the voice services to run in wireless is necessary. As we know this well that wireless is a contemporary technology due to it low cost and its effectiveness, and one major advantage of it is the mobility that is one fell free to move anywhere but have the access to the resource. So this makes wireless networks of great value, we in this thesis have focused on wireless LAN’s. In second part of the thesis we have shed some light on the VoIP showing how it works in the wireless environment. Analysis phase is relatively more important phase then the previous section which shows issues or hindrances in carrying voice over wireless environment. This analysis shows that these issues still prevails and should be addresses and the corresponding results are also discussed and by looking at those results we have derived a summery out of it. Next chapter we firstly tried to explain why we have chosen specific protocols and then showing some graphical representation measurements that are to address the problem based on the work done. We tried to evaluate EDCF and DCF as these play important role in handling real time applications like voice. After that we proposed a scheme through which these effects can be minimized and to enhance the method is necessary to avoid the issues still in effect. / Thesis is Part for Master program in Electrical Engineering with Emphasis on Telecommunication(2007-2009).We have had a very nice time doing this thesis as there was alot of learning. Our examinator was allways there to help us, we are thankfull to Richard for his endless support.

IEEE 802.15.4 is a standard designed for low data rate wireless personal area networks (WPANs) intended to provide connectivity to mobile devices. Such devices present considerable storage, energy, and communication constraints. However, they can be used in a variety of applications like home/office automation, environmental control and more. In order to extend the lifetime of the WPAN, we propose some changes to the standard including modifications to the Superframe Guaranteed Time Slot (GTS) distribution which can be optimized to reduce energy consumption. We implemented the proposed improvements to the IEEE 802.15.4 protocol using real sensor nodes. Specifically, we conducted an energy study of the proposed acknowledgment-based GTS descriptor distribution scheme and compared the results with the standard implementation. Experiments show that the proposed changes reduce energy consumption up to nearly 50% when 7 devices allocate guaranteed time slots descriptors during normal communication.