PRECODING FOR MULTICARRIER MODULATION SYSTEMS

摘要

Systems, methods, and instrumentalities are disclosed for selecting a precoding matrix for orthogonal frequency division multiplexing (OFDM) transmission. A wireless transmit/receive unit (WTRU) may determine a preceding matrix. The precoding matrix may be determined for a frequency band associated with a plurality of devices. A portion of the frequency band allocated to a device of the plurality of devices may be determined. A portion of the precoding matrix associated with the portion of the frequency band may be determined. Data may be sent using the portion of the preceding matrix. For example, the portion of the frequency band allocated to the given transmitter may be a plurality of OFDM subcarriers. The precoding matrix may be determined as a function of a number of devices and/or an available bandwidth of the frequency band. Spectral precoding applies to a set of K synchronized users and each spectrally precoded user spans the whole set of N subcarriers available to the K users. Since the users are synchronized, orthogonality between the N subcarriers and the users is maintained.