Abstract: A transmitter for transmitting data as a pulsed ultrawide band signal comprises a serial-to-parallel converter (54) for converting the signal to be transmitted to a parallel sequence, a modulator (64) to convert the parallel sequence to a parallel stream of impulse trains. A delay unit (60) delays the parallel streams of impulse trains by different time intervals within the same pulse repetition period. The delayed pulse streams are combined so that the pulses in the streams occur within the pulse repetition period of a single pulse. An antenna (52) is used to transmit the combined signal. A receiver comprises an antenna (72) for receiving a transmitted pulsed ultrawide band signal having two or more interleaved pulse trains with equal pulse repetition periods, the pulse repetition period being greater than the pulse spacing in the interleaved signal. A matched filter filters the received signal, the filter being matched to the pulse shape of the received signal.

Abstract: A system such as a code division multiple access (CDMA) system or an ultrawide band (UWB) system comprises a transmitter and a receiver. The transmitter includes a sequence extender for extending the incoming signal and a spreader for spreading the extended signal, the spreader input being coupled to the sequence extender output. A pulse shaper is coupled to the spreader output to provide a transmitter output signal. The transmitter output signal which has an associated chip rate is received by the receiver and is passed to a filter to select a number of input signals from the received signals. The signal is the passed to a sequence extension remover for removing a number of chips from the signal. The received signal is despread to a symbol rate which is less than the chip rate at which the received signal was spread prior to being received by the receiver. A frequency domain equalizer is provided to form a frequency equalized signal from the modified signal.

Abstract: A variable spreading factor-orthogonal frequency and code division multiplexing (VSF-OFCDM) system and receiver for use therein has a sequence extension remover for removing a predetermined number of chips from the received signal to form a modified signal, and a first converter for converting the modified signal from a serial sequence to a parallel sequence. A despreader is coupled to the first converter for despreading the parallel sequence to derive a group of symbols. An orthogonal transform block, such as a Fast Fourier Transform block is coupled to the despreader to transform the symbols from the time domain to the frequency domain. An equalizer block is coupled to the transform block for equalizing the transformed signal to reduce channel distortion. A deinterleaver block is coupled to the equalizer block to form a deinterleaved signal. The deinterleaved signal is then converted from a parallel sequence to a serial sequence.

Abstract: A code division multiple access (CDMA) system and methods for processing symbol blocks of a spread signal in both frequency and time domains are described. A transmitter (10) of the CDMA system spreads pilot symbols and data of the symbol blocks to derive a spread sequence. Thereafter, the spread sequence is extended with a predetermined number of chips and pulse shaped for transmission as the spread signal. A receiver (400) of the CDMA system receives the spread signal, removes the predetermined number of chips and then orthogonally transforms the spread signal to the frequency domain to derive a transformed signal. The transformed signal is equalized in the frequency domain to derive an equalized signal. The equalized signal is then inverse orthogonally transformed to an output in the time domain. The output is then despreaded to derive the symbol blocks.

Abstract: A code division multiple access (CDMA) system and methods for processing symbol blocks of a spread signal in both frequency and time domains are described. A transmitter (10) of the CDMA system spreads pilot symbols and data of the symbol blocks to derive a spread sequence. Thereafter, the spread sequence is extended with a predetermined number of chips and pulse shaped for transmission as the spread signal. A receiver (400) of the CDMA system receives the spread signal, removes the predetermined number of chips and then orthogonally transforms the spread signal to the frequency domain to derive a transformed signal. The transformed signal is equalized in the frequency domain to derive an equalized signal. The equalized signal is then inverse orthogonally transformed to an output in the time domain. The output is then despreaded to derive the symbol blocks.