Abstract: A method and apparatus for performing distributed computation of precoding estimates within a DAS. An RRH comprises a receiver component arranged to receive uplink signals from active user devices. The RRH further comprises a processing component arranged to perform channel estimation for each active user device m, based on the received uplink signals, to obtain channel estimates Hm,i between each active user device m and the RRH, compute intra-RRH interference precoding estimates Fm for each active user device m based on the channel estimates Hm,i, and solve interference-free conditions to obtain inter-RRH interference precoding estimates for each RRH j within the DAS.

Abstract: Methods and a system are described for generating a waveform for transmitting data over a channel divided into a plurality of adjacent frequency subcarriers. One method includes receiving a plurality of data bits, each destined for a different receiver of a plurality of receivers. For each received data bit, the method further includes coding the data bit using a unique spreading code of a first set of spreading codes to generate a corresponding group of multiple copies of a data symbol. Additionally, the groups of data symbols, corresponding to the plurality of data bits, are interleaved to generate a sequence of interleaved data symbols, and the sequence of interleaved data symbols is mapped to the plurality of adjacent frequency subcarriers to generate a waveform symbol.

Abstract: A method and apparatus for performing distributed computation of precoding estimates within a DAS. An RRH comprises a receiver component arranged to receive uplink signals from active user devices. The RRH further comprises a processing component arranged to perform channel estimation for each active user device m, based on the received uplink signals, to obtain channel estimates Hm,i between each active user device m and the RRH, compute intra-RRH interference precoding estimates Fm for each active user device m based on the channel estimates Hm,i, and solve interference-free conditions to obtain inter-RRH interference precoding estimates for each RRH j within the DAS.

Abstract: Methods and a system are described for generating a waveform for transmitting data over a channel divided into a plurality of adjacent frequency subcarriers. One method includes receiving a plurality of data bits, each destined for a different receiver of a plurality of receivers. For each received data bit, the method further includes coding the data bit using a unique spreading code of a first set of spreading codes to generate a corresponding group of multiple copies of a data symbol. Additionally, the groups of data symbols, corresponding to the plurality of data bits, are interleaved to generate a sequence of interleaved data symbols, and the sequence of interleaved data symbols is mapped to the plurality of adjacent frequency subcarriers to generate a waveform symbol.

Abstract: A cellular base station communicates data using both the licensed and unlicensed frequency spectrums. For each interval of a set of intervals (such as intervals corresponding to communication of LTE frames), the base station first identifies whether signaling is detected on a specified unlicensed frequency channel (UFC). If a signal is detected, the base station communicates data only over a licensed frequency channel (LFC) for the interval, and does not employ the UFC for the interval. If no signal is detected, the base station communicates data over the interval on both the LFC and the UFC. To ensure that other devices have the opportunity to use the UFC in a timely fashion, the base station communicates data over the UFC for only a portion of the interval.