WLC09-2: Channel Quality Feedback Schemes for 3GPP´s Evolved-UTRA Downlink

Today´s packet-based cellular systems typically are equipped with a channel quality reporting mechanism that supports scheduling and adaptive modulation/coding. When resources are scheduled not only in time but also in frequency the design of the return channel becomes intricate. The feedback signalling must balance improved cell-throughput with deteriorated spectral efficiency in the return link due to excessive signalling. In this contribution we examine system simulation results for the downlink of 3GPP´s long-term evolution system equipped with various signalling schemes. The simulations results show that for a certain uplink load in bits/s/Hz, emphasizing the quality of the mobile´s best channel instants (assigning these with more signalling bits) provides about 12% higher downlink throughput than capturing the quality of all channel instants equally well. Moreover, about 95% of the throughput provided by an ideal reference feedback scheme is obtained.