Abstract: Devices and methods for scheduling and interference cancellation that consider the interference cancellation capability of user equipment (UEs) are disclosed. Using reduced-rate sub-frame (or resource block) strategies, the transmission data rate to a scheduled user in a given cell may be reduced to ensure effective interference cancellation performance at the receiver of a co-scheduled user in another cell. By taking advantage of interference mitigation at one or more terminals, a scheduler may improve network spectral efficiency compared to existing inter-cell interference cancellation schemes, including almost blank sub-frame (ABS), further enhanced inter-cell interference coordination (FeICIC), and other resource partitioning schemes, such as reduced power sub-frames or frequency domain resource partitioning.

Abstract: According to one or more embodiments described and claimed herein, HARQ acknowledgements, re-transmissions, and related signaling (e.g., channel quality reports) are performed on a Re-transmission Extension Carrier (REC) separate from the primary downlink traffic carrier(s). In various embodiments, as explained herein, the REC may comprise an aggregated wireless communication network channel, which may be cross-channel scheduled or may have its own scheduler. The REC may be Frequency Domain Duplex (FDD) or Time Domain Duplex (TDD). The REC may be dedicated to a main downlink carrier, or may be shared across a plurality of aggregated component carriers. The REC may be transmitted from the same base station as one or more associated main carriers, or from a different base station. A shared REC may be operated in cooperative or contention modes. The REC may be implemented in unlicensed spectrum.

Abstract: Devices and methods for providing a pilot structure for a virtual diversity receiver (VDR) scheme are disclosed. In order to improve the performance of a communication network, a VDR scheme is implemented to facilitate the exchange of information between user devices via an intermediary device, such as a base station. The pilot structure supports estimation of channel parameters at the receivers, including true channel taps, as well as estimations of the virtual channels created by the VDR scheme in order to enable the use of receive-diversity signal processing techniques.

Abstract: Devices and methods for determining transmission rates based on a virtual diversity receiver (VDR) scheme are disclosed. Performance is improved through determination of appropriate transmission rates, which are determined based on one or more signal to interference plus noise ratios (SINRs). The SINRs are calculated using virtual noise and channel coefficient values obtained as part of the VDR scheme. Utilizing an underlying pilot structure a user device may receive several sets of symbols. These symbols are then used to obtain both real and virtual channel noise power values and channel coefficients. These values and coefficients are then used to determine first and second SINR values indicative of one or more channels in the communication network. These SINR values may correlate to transmission rates (modulation order and/or coding rate). The SINRs may be sent to a base station, or the user device itself may determine one or more transmission rates.

Abstract: The teachings herein provide a method and apparatus for partitioning sets of MIMO streams, for joint processing. In particular, there is an optimum or otherwise best partitioning of a set of MIMO streams into a first subset to be jointly processed and a second subset to be suppressed as interference with respect to that joint processing. Of course, more than one partitioning may be used, e.g., across different joint processing stages and/or at different times, such that all streams of interest are processed. Correspondingly, the present invention provides a method and apparatus for selecting an optimum or otherwise relative “best” subset of MIMO streams for processing together in a joint process, from among a larger set of MIMO streams. The method and apparatus may, for example, be employed in a multi-stage joint processing receiver, where subset selections are performed on a per-stage basis.

Abstract: Systems and methods utilize enhanced metrics for demodulation and/or soft bit information generation in the presence of a non-constant envelope modulated interfering signal. In one embodiment, a receiver includes a downconverter and a demodulator. The downconverter receives a radio frequency signal comprising a desired signal, noise, and a non-constant envelope modulated interfering signal, and downconverts the radio frequency signal to provide a downconverted signal. The demodulator demodulates the downconverted signal based on a demodulation metric that models the non-constant envelope modulated interfering signal as a stationary non-Gaussian random process with a probability distribution derived from a modulation constellation of a modulation used for the non-constant envelope modulated interfering signal. In one embodiment, the demodulator outputs demodulated symbols. In another embodiment, the demodulator outputs soft bit information.

Abstract: Systems and methods utilize enhanced metrics for demodulation and/or soft bit information generation in the presence of a non-constant envelope modulated interfering signal. In one embodiment, a receiver includes a downconverter and a demodulator. The downconverter receives a radio frequency signal comprising a desired signal, noise, and a non-constant envelope modulated interfering signal, and downconverts the radio frequency signal to provide a downconverted signal. The demodulator demodulates the downconverted signal based on a demodulation metric that models the non-constant envelope modulated interfering signal as a stationary non-Gaussian random process with a probability distribution derived from a modulation constellation of a modulation used for the non-constant envelope modulated interfering signal. In one embodiment, the demodulator outputs demodulated symbols. In another embodiment, the demodulator outputs soft bit information.

Abstract: A system and method in which a base station treats the Channel State Information (CSI) from wireless terminals as only partially-stale, and exploits this partially-stale CSI to predict the current channel from old estimates of the channel. The predicted channel is then used to design a precoder. The base station shapes the transmitted signal with the precoder so as to match it as closely as possible to the current channel. Particular embodiments thus combine the benefits of the stale feedback scheme with precoding to match the channel. Consequently, the signal received at a terminal is better conditioned, thereby providing a greater overall boost in performance of the communication arrangement between the base station and the terminal. The usage of partially-stale CSI can be important for dense networks with a large number of simple terminals.

Abstract: A receiver includes a constellation processing module and a multi-stage demodulator having a plurality of non-final demodulation stages and a final demodulation stage. The constellation processing module derives a set of centroid-based values from subsets of constellation points associated with a plurality of transmitted signals for input to each of the non-final demodulation stages. Each of the non-final demodulation stages demodulates a group of signals input to the non-final demodulation stage using the set of centroid-based values as constellation points and suppresses residual interference associated with using the set of centroid-based values as constellation points for signal demodulation. The final demodulation stage demodulates a group of modified signals input to the final demodulation stage using the subset of constellation points input to the final demodulation stage to determine a final symbol decision for the plurality of transmitted signals.

Abstract: Soft bit values are generated for received symbols transmitted based on a modulation constellation by demodulating the received symbols via a sequence of demodulation stages, each demodulation stage producing a symbol decision based on an effective constellation. Each effective constellation used by a non-final one of the demodulation stages includes subsets of centroids approximating a region of the modulation constellation. Adjacent ones of the subsets have one or more common points so that at least two adjacent subsets overlap. The soft bit values for the symbol decisions are determined based on detection metrics computed during demodulation for the points included in the effective constellation constructed incrementally over the sequence of demodulation stages, the effective constellation produced by the final demodulation stage being devoid of one or more points included in the modulation constellation.

Abstract: With the asymmetric resource sharing disclosed herein, a base station transmits fewer information symbols at some transmission times to one or more mobile terminals than to other mobile terminals at other transmission times. After transmitting the information symbols, the base station receives channel estimates from the mobile terminals, which the base station then use to generate synthesized signals representing estimates of the signals received at the mobile terminals. The base station subsequently combines complementary pairs of the synthesized signals to generate combined signals and transmits at least one of the combined signals to implement at least one virtual antenna for at least one of the mobile terminals.

Abstract: Demodulation methods and apparatus for a multi-stage SLI demodulator are disclosed. Residual signals from each demodulation stage are modeled as finite sets of unresolved signals and a new metric is introduced for use in search of best candidate symbol estimates. The metric may be evaluated based on a probability distribution function of the residual signals or a probability mass function of the unresolved signals. The metric may also be approximated by the sum of a conventional Euclidean metric and a correction metric. The best candidate symbol estimates generated from each stage of the multi-stage SLI demodulator are summed to form cumulative symbol estimates.

Abstract: An iterative demodulator and decoder uses feedback attenuation to maintain proper balance between the demodulator and decoder. Balance is maintained by attenuating the influence of extrinsic information fed back from the decoder to the demodulator to prevent strong decisions by the decoder from overwhelming the demodulator.

Abstract: Interference, such as inter-symbol interference, from a symbol of interest in a RAKE receiver is reduced. The RAKE receiver comprises a plurality of RAKE fingers, a processor, and a combiner. The plurality of RAKE fingers despread symbols received over multiple paths of a multi-path channel. The processor determines cross-correlations between symbol waveforms from different symbols and multiple paths. The combiner combines the despread symbols using the cross-correlations to reduce interference from the symbol of interest.

Abstract: Methods may be provided to simultaneously receive first and second RF (radio frequency) carriers over respective first and second RF carrier frequencies. More particularly, the first and second RF carriers may be provided at an RF mixer stage. During a first time period, the first and second RF carriers may be down converted through the RF mixer stage using a first RF mixer frequency to generate first downconverted signals, and the first downconverted signals may be processed to provide first and second DC carriers corresponding to the first and second RF earners. During a second time period, the first and second RF carriers may be downconverted through the RF mixer stage using a second RF mixer frequency to generate second downconverted signals with the first and second RF mixer frequencies being different, and the second downconverted signals may be processed to provide the first and second DC carriers corresponding to the first and second RF carriers. Related devices are also discussed.

Abstract: The delay associated with performing interference cancellation in a multi-user receiver is reduced by enabling partial decoding. According to an embodiment, interference is canceled from a received signal having signal contributions from multiple users by partially decoding a first codeword obtained from the received signal and transmitted by a first user via a first signal. The first signal is reconstructed based on the partial decoding of the first codeword and canceled from the received signal to yield a reduced-interference signal. A second codeword obtained from the reduced-interference signal and transmitted by the first user or a second user via a second signal is at least partially decoded. In one embodiment, the first codeword is partially decoded by puncturing one or more coded bits of the first codeword and decoding the first codeword based on the one or more punctured coded bits and estimates of the remaining coded bits.

Abstract: In a receiver with a multi-stage equalizer, such as an SLI equalizer, cumulative symbol estimates generated in one or more early stages of the equalizer are used as effective pilot symbols to improve channel estimation for later stages.

Abstract: Communications between a base station and a mobile station is improved through using a relay station. A transmit timing of relayed signals from the relay station is controlled so that the signals from the base station and the relay station arrive to the mobile station aligned with each other within a predetermined tolerance.

Abstract: A receiver includes a constellation processing module and a multi-stage demodulator having a plurality of non-final demodulation stages and a final demodulation stage. The constellation processing module derives a set of centroid-based values from subsets of constellation points associated with a plurality of transmitted signals for input to each of the non-final demodulation stages. Each of the non-final demodulation stages demodulates a group of signals input to the non-final demodulation stage using the set of centroid-based values as constellation points and suppresses residual interference associated with using the set of centroid-based values as constellation points for signal demodulation. The final demodulation stage demodulates a group of modified signals input to the final demodulation stage using the subset of constellation points input to the final demodulation stage to determine a final symbol decision for the plurality of transmitted signals.

Abstract: Techniques for spherical decision-feedback sequence estimation are disclosed. A received signal is equalized by forming a trellis comprising a plurality of stages, each stage corresponding to a symbol time and comprising a plurality of nodes, each having a node state. A most likely received symbol sequence is identified by evaluating cumulative state metrics for the nodes according to MLSE or DFSE criteria. The trellis is formed by selecting a set of fan-out branches for each node by identifying, of all possible state transition branches from the node to successor nodes in the succeeding stage, those state transition branches that have a spherical branch metric less than a pre-determined metric limit, and determining the cumulative state metric for each node as a function of the cumulative state metrics for predecessor nodes in the preceding stage and the spherical branch metrics for fan-out branches connecting the predecessor nodes to the node.