Patent ID: 7400686

Claim:
An apparatus comprising: a transmitter for transmitting a time domain signal, wherein the transmitter comprises: an orthogonal frequency division multiplexing (OFDM) modulator that divides a modulated information-bearing signal into a plurality of streams, spreads each of the plurality of streams with a spreading code, sums the spread streams into an input vector X of length N b , divides the input vector X of length N b into two parts, inserts N x zeros between the two parts, and takes an inverse fast Fourier transform (IFFT) of size N b N x to obtain a time-domain signal; and a pulse-shaping filter coupled to the OFDM modulator for processing the time-domain signal prior to transmission; and a receiver for receiving the transmitted time-domain signal, wherein the receiver comprises an OFDM demodulator for taking a fast Fourier transform (FFT) of size N b N x of the received signal and removes the zeros inserted in the transmitter from the resulting frequency-domain signal.