Orthogonal multi–beam techniques for multi-user diversity and multiplexing gain in packet-based wireless systems

Abstract

In this paper, we consider the use of multiple beams to simultaneously achieve both diversity and multiplexing gain in multi-user domain in multiple access systems. Orthogonal multiple beams are generated to provide the users with multiple channels at the same time, achieving multi-user diversity through each channel. However, when the number of active users is not large, the performance can significantly be affected by the interference from other users. To alleviate this problem, we propose a multi-beam scheme to adjust the number of beams according to the channel condition or the number of users.