Spreading and precoding in OFDM
AssigneeGenghiscomm Holdings, LLC
InventorSteve Shattil
Life of this patent
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Abstract
An OFDM transmitter spreads original data symbols with a complex-valued spreading matrix derived from a discrete Fourier transform. Spread data symbols are mapped to OFDM subcarriers. Spreading and mapping are configured to produce a transmitted spread-OFDM signal with a low peak-to-average power ratio (PAPR) and orthogonal code spaces. In MIMO systems, the complex-valued spreading matrix can comprise a MIMO precoding matrix, and the code spaces can comprise MIMO subspaces. In Cooperative-MIMO, a combination of low code-space cross correlation and low PAPR can be achieved.
Claims28
A computer program product, comprising a non-transitory computer-readable medium having computer readable program code stored therein, said program code containing instructions executable by one or more processors of a computer system to implement a method comprising:
- performing a first discrete Fourier transform (DFT) on a received spread-Orthogonal Frequency Division Multiplexing (OFDM) signal to produce a demodulated signal;
- and
- performing a second DFT on the demodulated signal to produce decoded data symbols, wherein the second DFT is an inverse of a DFT employed by a transmitter to spread data symbols across OFDM subcarriers.
A method, comprising:
- performing a first discrete Fourier transform (DFT) on a received spread-Orthogonal Frequency Division Multiplexing (OFDM) signal to produce a demodulated signal;
- and
- performing a second DFT on the demodulated signal to produce decoded data symbols, wherein the second DFT is an inverse of a DFT employed by a transmitter to spread data symbols across OFDM subcarriers.
An apparatus comprising:
- a processor;
- and
- a memory coupled to the processor, the memory including a set of instructions stored therein and executable by the processor to:
- perform a first discrete Fourier transform (DFT) on a received spread-Orthogonal Frequency Division Multiplexing (OFDM) signal to produce a demodulated signal;
- and
- perform a second DFT on the demodulated signal to produce decoded data symbols, wherein the second DFT is an inverse of a DFT employed by a transmitter to spread data symbols across OFDM subcarriers.
An apparatus, comprising
- a first discrete Fourier transform (DFT) to demodulate coded data symbols modulated on OFDM subcarriers of a received Orthogonal Frequency Division Multiplexing (OFDM) signal;
- and
- a second DFT to decode the coded data symbols for generating decoded data symbols, wherein the second DFT performs the inverse of a DFT employed by a transmitter to spread data symbols across OFDM subcarriers.
Dependencies are inferred from the claim text.