Capacity and variable data rate for wireless communications

The general trend in wireless technology development is to increase communication capacity for mass market. The propagation problem and limited frequency spectrum still exist. How to achieve the goal of the wireless technology is an important issue. In this work we study the trade off between interference and variable data rate of a typical DPSK link. The objective is to find out what data rate is tolerable for message services under interference. From the study it is realized that interference is the most important issue involved in any multiple access systems. To account for more accurately the relationship between variable data rate and capacity it is also necessary to discuss the quality of service (QOS). This can be either at the link level, i.e. BER or at a higher level such as outage probability. Simulation results showed multipath fading interference has a detrimental effect on single channel data rate. A simple analysis is done to show user capacity, QOS and power management in an uncoordinated multiple access system