Throughput Study for a Dynamic OFDM-FDMA System with Inband Signaling

OFDM-FDMA systems provide the flexibility to support simultaneous downlink data transmissions to different terminals. By dynamically assigning different sets of subcarriers to different terminals they also have the potential to react to fast changing attenuation states of wireless channels. It has been shown that hence dynamic OFDM-FDMA systems can improve various transmission metrics such as throughput or required power. However, these dynamic systems require a signaling mechanism informing each terminal prior to the data transmission itself which subcarriers they have been assigned. We study the dependency between overhead caused by the signaling system and number of subcarriers used in the system for a varying number of terminals in the cell. We find that in terms of resulting throughput per terminal there exists an optimal number of subcarriers into which the bandwidth should be split. This optimal number depends on the setting (especially, terminal number) and provides, if used, a significant performance increase compared to using a fixed number of subcarriers.QC 20140102