Dynamic OFDM-FDMA systems under realistic assumptions: On the influence of channel knowlegde and inband signaling

Wireless OFDM systems offer the opportunity to transmit data simultaneously on the downlink of a cell to different wireless terminals by assigning different sets of subcarriers to different terminals. Due to the timeand frequency varying nature of subcarrier gains doing this dynamically has been shown to be beneficial in terms of various transmission metrics, i.e. average throughput, consumed power etc. . The potential of these dynamic subcarrier assignment schemes depends on two requirements. First, the access point has to “know” all subcarrier gains of all terminals in order to decide which terminals will receive which subcarrier. Second, after this decision has been made the terminals have to be informed of their assigned subcarrier sets. This task might be solved by a signaling system. So far, recent studies have always just assumed the existence of these two requirements without any cost. In this report we study the impact of explicitly implementing these two tasks in a dynamic assignment system, answering the question: which degree of advantage remains after considering realistic channel knowledge and an implemented signaling system.