A system may include at least one antenna for receiving a first receive signal having a first signal diversity property and a second receive signal having a second signal diversity property. A first signal path may include a first frequency converter for downconverting the first receive signal to a first intermediate frequency signal having a first intermediate frequency. A second signal path may include a second frequency converter for downconverting the second receive signal to a second intermediate frequency signal having a second intermediate frequency. A transducer module may route the first receive signal to the first signal path, and route the second receive signal to the second signal path. A first N-plexer may select the first intermediate frequency signal or the second intermediate frequency signal for transmission to a cable, and to provide a data signal based on a selected intermediate frequency signal to the cable.

The present disclosure concerns receivers for use in nodes or devices that participate in wireless communications. In one exemplary embodiment, the receiver receives a first signal attributable to a first carrier and a second signal attributable to a second carrier. A first path searcher detects taps in the first signal attributable to the first carrier. A second path searcher detects taps in the second signal attributable to the second carrier. A channel tap selector selects, based on received energy values for taps detected by the first path searcher and the second path searcher, which tap values are to be used for taps of the receiver for both the first carrier and the second carrier.

A method for processing one or more received radio signals is provided. The method may include performing a channel estimation of a transmission channel for at least a portion of the one or more radio signals received, to identify at least one soft channel parameter representing a channel impulse response of the transmission channel, and identifying at least one soft intercarrier interference parameter representing an interference for the one or more radio signals received using a first frequency carrier. The interference is caused by the one or more radio signals received using a second frequency carrier. The method may further include detecting soft data from the one or more radio signals based at least on the at least one soft channel parameter and the at least one soft intercarrier interference parameter.

Techniques are described for carrier frequency offset (CFO) and channel estimation of orthogonal frequency division multiplexing (OFDM) transmissions over multiple-input multiple-output (MIMO) frequency-selective fading channels. A wireless transmitter forms blocks of symbols by inserting training symbols within two or more blocks of information-bearing symbols. The transmitter applies a hopping code to each of the blocks of symbols to insert a null subcarrier at a different position within each of the blocks of symbols, and a modulator outputs a wireless signal in accordance with the blocks of symbols. A receiver receives the wireless signal and estimates the CFO, and outputs a stream of estimated symbols based on the estimated CFO.

A communication device is described comprising a plurality of receive paths, wherein each of the plurality of receive paths is configured to extract a multipath component of a received signal, a determiner configured to determine whether at least two of the plurality of receive paths fulfil a mutual interference correlation criterion among the plurality of receive paths and a processor configured, if at least two of the plurality of receive paths fulfil the interference correlation criterion among the plurality of receive paths, to determine the sent signal based on canceling or mitigating the interference between the multipath components of the received signal extracted by the at least two receive paths.

Methods, systems, and devices are described for orthogonal modulation of signals using maximal length sequences and Hadamard transforms. Modulation symbols to be transmitted are arranged into sequences indexed from 1 to 2.sup.n1 for some integer n. A constant is added to the beginning of each sequence, which is then multiplied by a Hadamard matrix of size 2.sup.n2.sup.n. The resulting sequences will be orthogonal and will have a first value of zero. The first value is discarded, and the sequence are reordered and associated with m-sequences. The signal is then transmitted. A cyclic prefix may also be transmitted. Upon receiving the transmission, a receiver may discard the cyclic prefix or use it for channel equalization. The receiver may then reorder the received signal, insert a zero, apply the 2.sup.n2.sup.n Hadamard transform, discard the zero, and order the sequences again according to the index to retrieve the data.

Estimating and compensating the frequency offset between a transmitter and a receiver is essential for reliable communication in wireless communication systems. Before a client terminal synchronizes with a base station, the initial frequency offset may be high. The frequency offset estimation may need to be performed even without having time synchronization with a base station. In case of cellular systems multiple base stations may be using the same RF channel to transmit their signals. The signals from different base stations may be superimposed at the receiver of the client terminal. A method and apparatus are disclosed for frequency offset estimation in presence of the signals from multiple base stations and with unknown timing of the base station.

Techniques are described for carrier frequency offset (CFO) and channel estimation of orthogonal frequency division multiplexing (OFDM) transmissions over multiple-input multiple-output (MIMO) frequency-selective fading channels. A wireless transmitter forms blocks of symbols by inserting training symbols within two or more blocks of information-bearing symbols. The transmitter applies a hopping code to each of the blocks of symbols to insert a null subcarrier at a different position within each of the blocks of symbols, and a modulator outputs a wireless signal in accordance with the blocks of symbols. A receiver receives the wireless signal and estimates the CFO, and outputs a stream of estimated symbols based on the estimated CFO.