Efficiency Based Feedback Reduction

Most of up-to-date wireless data systems are based on the OFDM technology and employ the opportunistic scheduling to exploit channel itself fully. Thus, feedback reduction in multiuser multi-carrier systems becomes more of an issue due to the large amount of feedback required to pass to the base station. In this paper, we propose a novel feedback reduction scheme preserving the essential of multi-user diversity. In our proposed scheme, active users determine their feedback amount based on the feedback efficiency factor in a distributed manner. The objective is to reduce the feedback load remarkably while achieving almost the same performance to the full feedback condition. Our proposed scheme offers several advantages over existing ones. First, it does not distort the property of the scheduling policies. Second, total feedback load can be explicitly controlled to a target level regardless of the number of users in a system by adjusting each user's feedback load adaptively.