Multi-User Scheduling for OFDM Downlink with Limited Feedback for Evolved UTRA

Multi-user scheduling and OFDM techniques are well regarded as promising candidates to provide high data- rate and reliable transmissions in future communication systems. To optimally exploit multi-user diversity and frequency selectivity, exhaustive channel information is needed for every user - an impracticality given limited feedback bandwidth. Simple and efficient feedback schemes therefore become a crucial task in designing a next generation standard. In this paper, two near-optimal feedback schemes are proposed that achieve most of the multi-user scheduling benefit with very few feedback bits. It is also shown that the feedback schemes are robust to long feedback intervals. As expected, at higher Doppler spread, the performance gap using the proposed schemes becomes larger but still provides satisfactory performance.