A transmitter and a receiver for communicating data using at least two separate RF channels using channel bundling. The transmitter includes a data stream partitioner configured to partition a data stream of data to be communicated into two or more stream partitions, two or more modulators configured to each receive a stream partition and to generate modulated data from the received stream partition, and an interleaver configured to assign the modulated data generated by a modulator from a received stream partition to different RF channels for transmission.

A first wireless communication apparatus assigns a pilot signal without an effective signal component at least in an adjacent frequency component to a generated transmit signal, and transmits the transmit signal including the pilot signal. A second wireless communication apparatus converts the received signal or a frequency-converted signal obtained by frequency conversion of the signal into a signal in a frequency domain, sets an approximate value of the distance between the second wireless communication apparatus and the first wireless communication apparatus, calculates a coefficient γk, based on the approximate value of the distance, the effective bandwidth, the speed of light, the number of FFT points, and the frequency component number, extracts a signal in the frequency domain, generates a phase noise compensated sampling signal, and reproduces data transmitted by the first wireless communication apparatus.

A signal generation method includes phase-changing baseband signals with respective phase changing patterns to generate respective phase-changed signals, each of the phase changing patterns being different from each other, and inverse-fast-Fourier-transforming the phase-changed signals to respective orthogonal frequency division multiplexing (OFDM) transmission signals. Each phase changing pattern has N candidates for an amount of change in a phase, N being an integer greater than two, and each candidate is periodically selected from the N candidates based on subcarriers of the respective OFDM transmission signals, a phase of the respective baseband signals being changed by the each candidate.

A node is provided that is configured to communicate in a cooperative broadcast multi-hop network that employs broadcast flood routing and multi-hop transmission using a direct-sequence spread-spectrum (DSSS) waveform. The node includes an antenna and a waveform module having a receiver processing chain. The antenna can receive a plurality of DSSS signals from other nodes on a particular channel, and output a channel that includes the plurality of DSSS signals. The plurality of DSSS signals include transmissions that are directly received from other nodes and multi-path components of those transmissions. The receiver processing chain can include a multi-user RAKE receiver that can combine, when performing demodulation processing, a plurality of transmissions directly received from the other nodes and multipath components of transmissions received from the other nodes. In some implementations, the node can perform cooperative beamforming and adaptive space-spectrum whitening.

A receiver is provided that includes a multi-user RAKE receiver that can receive a plurality of transmissions directly received from a plurality of nodes of a cooperative broadcast multi-hop network and multipath components of those transmissions, a combiner module and a data despreader module. The multi-user RAKE receiver includes correlator blocks for each node and a finger selection module. Each correlator block generates one or more candidate fingers for that particular node. The finger selection module can select a subset of the candidate fingers having sufficient correlation for further processing. The combiner module can combine aligned symbols for the subset of candidate fingers to generate and combine soft decisions across each of a plurality of channels into a joint soft decision. The data despreader module can despread chips of information from each of the plurality of channels to generate demodulated data symbols that are converted into data soft-decision bits.

Transmission quality is improved in an environment in which direct waves dominate in a transmission method for transmitting a plurality of modulated signals from a plurality of antennas at the same time. All data symbols used in data transmission of a modulated signal are precoded by hopping between precoding matrices so that the precoding matrix used to precode each data symbol and the precoding matrices used to precode data symbols that are adjacent to the data symbol in the frequency domain and the time domain all differ. A modulated signal with such data symbols arranged therein is transmitted.

Transmission quality is improved in an environment in which direct waves dominate in a transmission method for transmitting a plurality of modulated signals from a plurality of antennas at the same time. All data symbols used in data transmission of a modulated signal are precoded by hopping between precoding matrices so that the precoding matrix used to precode each data symbol and the precoding matrices used to precode data symbols that are adjacent to the data symbol in the frequency domain and the time domain all differ. A modulated signal with such data symbols arranged therein is transmitted.

A receiver circuit for separating a plurality of layers multiplexed in an orthogonal frequency domain multiplexed (OFDM) signal includes: a descrambling sub-circuit configured to descramble a plurality of signals received on non-adjacent subcarriers of the OFDM signal to generate a plurality of descrambled signals; an inverse fast Fourier transform sub-circuit configured to transform the descrambled signals from a frequency domain to a received signal including a plurality of samples in a time domain; and a layer separation sub-circuit configured to separate the layers multiplexed in the received signal by: defining a first time domain sampling window and a second time domain sampling window in accordance with a size of the inverse fast Fourier transform; extracting one or more first layers from the samples in the first time domain sampling window; and extracting one or more second layers from the samples in the second time domain sampling window.

A node is provided for a cooperative broadcast multi-hop network that employs broadcast flood routing and multi-hop transmission. The node includes antennas and a waveform module having a receiver processing chain that can include an adaptive space-spectrum whitener (ASSW) module and a multi-user RAKE (mRAKE) receiver. Each antenna can receive output a channel that includes direct-sequence spread-spectrum signals received from other nodes and multi-path components of those transmissions. The ASSW module can perform adaptive space-spectrum whitening to detect and remove interference signals received from each of the channels by performing a covariance analysis to generate channelized signals. The ASSW module can include modified Discrete Fourier Transform (MDFT) analysis and synthesis modules that generate an interference mitigated time-domain channelized signals. The mRAKE receiver, when performing demodulation processing, can combine the interference mitigated time-domain channelized signals to generate fingers that combine components of transmissions received from the other nodes.

An OFDM transmitter and an OFDM receiver respectively transmit and receive N (N≥2, N is an integer) control symbols. For each control symbol, a guard interval time-domain signal is, for example, identical to a signal obtained by frequency-shifting at least a portion of a useful symbol time-domain signal by an amount different from any other symbol, or to a signal obtained by frequency-shifting one or both of a portion and a span of a useful symbol interval time-domain signal different from any other symbol by a predetermined amount.