In wireless communication systems, users with heterogeneous information content such as data, voice, and multimedia constrain the network by having different reliability requirements. In this project a framework which can provide heterogeneous reliability guarantees for the users is considered. This adds a completely new dimension to the trade-off of performance in a wireless network, and is unique to multiterminal communication systems. It is as if the network has some amount of reliability that can be allocated among the users. This is a very general concept and can be applied in any multiterminal communication problem.
This is accomplished by defining individual probabilities of errors for the users in the network. Hence for a fixed vector of rates of the users, a system can provide a trade-off of reliabilities among the users. This set of achievable reliabilities is referred to as the multiuser reliability profile of a multiuser network. This profile is a function of the vector of transmission rates inside the capacity region. For a wireless system employing multiple antennas, this profile is referred to as multiuser diversity gain profile. Further, these guarantees are directly manifested in the physical layer and can be translated into QoS guarantees in the higher layers in the network architecture. This is a marked shift from conventional approaches that relegate this task to the higher network layers. Hence in a heterogeneous wireless networks, heterogeneous QoS guarantees can be more efficiently realized using the techniques considered in this project. This project is expected to have a significant impact on the design of the next generation of wireless networks.
