Abstract: A method, receiver and program for equalising digital samples of a radio signal received over a wireless communications channel. The method comprises: receiving digital samples of the radio signal; calculating equaliser coefficients in the frequency domain; transforming the equaliser coefficients from the frequency domain to the time domain; and equalising the digital samples in the time domain using the transformed time domain equaliser coefficients.

Abstract: Systems are described that reduce or obviate the impact of limited processing resources and/or limit the power consumption in a receiver having signal processing functions at least partially implemented in software. A wireless receiver includes reception means for receiving a signal over a wireless channel in a wireless external environment. The receiver includes storage means, and a processor configured to perform a plurality of signal processing functions for extracting processed data from said signal, each of said signal processing functions having a plurality of alternative software implementations requiring different levels of usage of a processing resource. The processor estimates at least one parameter relating to the external environment and selects and executes one of the software alternatives for each of the respective signal processing functions to apply a set of implementations adapted to a required quality of said processed data. Related methods and computer program products are described.

Abstract: A method, apparatus and program. The method comprises: receiving a signal comprising a sequence of encoded symbols, each corresponding to one of a plurality of possible states; for each symbol in the sequence, determining a set of state metrics each representing a probability that the respective symbol corresponds to each of the plurality of states; and decoding the signal by processing runs of recursions, using runs of forward recursions and runs of reverse recursions. The decoding comprises performing a plurality of repeated iterations over the sequence, and for each iteration: dividing the sequence into a plurality of smaller windows, processing the windows using separate runs of recursions, and performing an associated warm-up run of recursions for each window.

Abstract: Techniques are described for optimizing processing facilities of a receiver in a wireless communication environment, taking into consideration processing performance set against the computing resources and/or power consumption required to obtain the processing performance. An embodiment of a radio receiver is described that includes a channel equalization means arranged to receive digital samples of an incoming signal and to generate an equalized output, said channel equalization means including means for processing said digital samples in accordance with an equalizer algorithm utilizing a set of equalizer parameters. The receiver can include means for estimating at least one parameter of a channel over which the signal has been received, and means for selecting at least one of said equalizer parameters based on at least one of said estimated channel parameters. Related methods, algorithms, and computer program products are also described.

Abstract: A method of generating a reliability indicator for decoding an encoded signal transmitted from a transmitter to a receiver via a wireless channel subject to fading. The method comprises: receiving symbols of the encoded signal; generating a reliability indicator for decoding at least some of the symbols selectively based on one or both of a statistical model representing additive white Gaussian noise (AWGN) in the encoded signal and a statistical model representing fading of the encoded signal; and selecting the statistical model based on signal characteristics of the wireless channel.

Abstract: A method, program and apparatus for transmitting from a transmitter to a receiver over a channel using a transmit diversity scheme. The method comprises: receiving power-related information fed back from the receiver to the transmitter; and at the transmitter, using the power-related information to generate channel state information. The method further comprises using the generated channel state information to control for subsequent transmission to the receiver from the multiple transmit antennas of the transmitter.

Abstract: A method for limiting peak-to-average power of a signal transmitted from a power amplifier. The method comprises: applying a pulse-shape filter to a first signal, thereby generating a second signal being a filtered version of the first signal; and outputting the second signal for transmission from a power amplifier. The method further comprises: applying each of a plurality of predictor filters to a respective instance of the first signal, each predictor filter approximating the application of the pulse-shape filter to the first signal based on a different respective set of filter coefficients, and each thereby generating a respective third signal. The method also further comprises determining an indicator of amplitude of each of the third signals, selecting the indicator corresponding to the largest of those amplitudes, generating a modifier based on the selected indicator, and using the modifier to limit the first signal prior to applying the pulse-shape filter.

Abstract: Methods are described of processing signals received over a wireless communication channel by a receiver in a wireless cellular network. A method includes receiving a sequence of signal samples. The received sequence of samples can be used to estimate at least one channel coefficient for at least one transmission path. An estimate of an orthogonality factor can be generated based on said at least one channel coefficient. An estimate of the disturbance can be generated based on said at least one estimated channel coefficient. An estimate of input signal power can be generated using the received sequence. An estimate of cell geometry can be generated using the estimated orthogonality factor, estimated disturbance, and estimated input signal power. The estimate of cell geometry can be used in processing received data samples. Related methods of processing digital samples are described. Related receivers are also described.

Abstract: An apparatus and method for implementing an equalizer which (1) combines the benefits of a decision feedback equalizer (DFE) with a maximum-a-posterori (MAP) equalizer (or a maximum likelihood sequence estimator, MLSE) (2) performs equalization in a time-forward or time-reversed manner based on the channel being minimum-phase or maximum-phase to provide an equalization device with significantly lower complexity than a full-state MAP device, but which still provides improved performance over a conventional DFE. The equalizer architecture includes two DFE-like structures, followed by a MAP equalizer. The first DFE forms tentative symbol decisions. The second DFE is used thereafter to truncate the channel response to a desired memory of L1 symbols, which is less than the total delay spread of L symbols of the channel. The MAP equalizer operates over a channel with memory of L1 symbols (where L1<=L), and therefore the overall complexity of the equalizer is significantly reduced.

Abstract: The invention relates to a method of feeding back information from a receiver to a transmitter, and also a corresponding receiver, transmitter, system comprising a receiver and transmitter, and computer program products for performing the steps of the receiver and transmitter respectively. The method comprises: receiving signals at the receiver from the transmitter over a wireless multiple-input-multiple-output channel; and, based on the received signals, transmitting back reports from the receiver to the transmitter including a report indicating a pre-coding matrix and a report indicating a rank of the pre-coding matrix. In the event that the report indicating the rank is not transmitted, the receiver instead uses a default rank to determine the report.

Abstract: Method and receiver for processing a signal in a wireless communication system in which the signal comprises a sequence of chips. The signal is receive data at least one rake finger and sampled. There is a time spacing t1 between successive samples less than the time spacing tc between successive chips in the signal. Channel conditions on the channel are estimated and based on estimated channel conditions by the following steps: monitoring timing of the signal on one of the at least one rake finger to determine a time difference between the timing of the signal on the one of the at least one rake finger and the timing of the generation of the samples, the determined time difference being a multiple of t2, where t2<t1; aligning the timing of the generation of the samples with the timing of the signal on the one of the at least one rake finger to within a timing range t2.

Abstract: A method, program and system for transmitting from a transmitter to a receiver over a wireless multipie-input-multiple-output channel. In one aspect, the method may comprise encoding precoding information fed back from the receiver to the transmitter according to a differential encoding scheme, and resetting the differential encoding scheme upon detecting a condition. In another aspect, the method may comprises encoding precoding matrices fed back from the receiver to the transmitter relative to a most-probable subset of precoding matrices. In another aspect, the method may comprise transmitting an indication of and/or the size of a preferred subset of precoding matrices for use in the encoding.

Abstract: In one aspect, there is provided a method of processing a signal received using a wireless communication channel by a receiver in a wireless cellular network. In one embodiment, the method comprises receiving signal samples of a signal to be processed from a serving cell, identifying a second of dominant interfering cells generating an interfering signal, using a number of cells in the set to select an interference scenario, and using the selected interference scenario and at least one parameter related to the serving cell and the interfering cells to select a processing function for processing the signal.

Abstract: There is disclosed a method of determining one or more candidate frequencies for a carrier signal in a received signal, which method comprises: generating a narrowband spectrum of the received signal; detecting one or more peaks in the narrowband spectrum; generating a candidate frequency list, each frequency at which a peak occurs being included in the candidate frequency list. The method further comprises: removing the detected one or more peaks from the narrowband spectrum to generate a modified narrowband spectrum; detecting one or more further peaks in the modified narrowband spectrum; and modifying the candidate frequency list in dependence on the one or more further peaks.

Abstract: According to an embodiment of the invention, a method and system is disclosed for determining log-likelihood ratios for a coded set of individual bits (40) of a quadrature amplitude modulation (QAM) codeword. In the method at most two constant values (33,35) may be determined to perform a set of predetermined functions, the output of each of function is based on the constant values and at least one received component corresponding to the codeword, to determine log-likelihood ratios (37) for each individual bit of the set of individual bits of the codeword. The QAM codeword may correspond to at least a portion of a signal of a wireless device, such as a mobile third-generation device operating according to a Wideband Code-Division Multiple Access (WCDMA) standard.

Abstract: Systems are described that reduce or obviate the impact of limited processing resources and/or limit the power consumption in a receiver having signal processing functions at least partially implemented in software. A wireless receiver includes reception means for receiving a signal over a wireless channel in a wireless external environment. The receiver includes storage means, and a processor configured to perform a plurality of signal processing functions for extracting processed data from said signal, each of said signal processing functions having a plurality of alternative software implementations requiring different levels of usage of a processing resource. The processor estimates at least one parameter relating to the external environment and selects and executes one of the software alternatives for each of the respective signal processing functions to apply a set of implementations adapted to a required quality of said processed data. Related methods and computer program products are described.

Abstract: Wireless receivers are described for receiving signals from a transmitter. A receiver can include a plurality of antennas each for receiving a version of a signal via a different propagation channel and providing that version to a respective input. Signal processing means can be included and configured to operate diversity processing of a supplied number of said inputs for use in performing detection of said signal. The receiver can include channel parameter estimation means, configured to estimate one or more channel parameters on the propagation channels. The receiver can also include selection means configured to select only a subset of said inputs to implement a specific dimensionality of the receiver diversity processing, in dependence on the one or more channel parameters indicative of channel conditions on said propagation channels. The diversity processing can be linear or non-linear. Related methods and software implementations and computer program products are also described.

Abstract: Techniques are described for optimizing processing facilities of a receiver in a wireless communication environment, taking into consideration processing performance set against the computing resources and/or power consumption required to obtain the processing performance. An embodiment of a radio receiver is described that includes a channel equalization means arranged to receive digital samples of an incoming signal and to generate an equalized output, said channel equalization means including means for processing said digital samples in accordance with an equalizer algorithm utilizing a set of equalizer parameters. The receiver can include means for estimating at least one parameter of a channel over which the signal has been received, and means for selecting at least one of said equalizer parameters based on at least one of said estimated channel parameters. Related methods, algorithms, and computer program products are also described.

Abstract: Methods are described of processing signals received over a wireless communication channel by a receiver in a wireless cellular network. A method includes receiving a sequence of signal samples. The received sequence of samples can be used to estimate at least one channel coefficient for at least one transmission path. An estimate of an orthogonality factor can be generated based on said at least one channel coefficient. An estimate of the disturbance can be generated based on said at least one estimated channel coefficient. An estimate of input signal power can be generated using the received sequence. An estimate of cell geometry can be generated using the estimated orthogonality factor, estimated disturbance, and estimated input signal power. The estimate of cell geometry can be used in processing received data samples. Related methods of processing digital samples are described. Related receivers are also described.

Abstract: A method of processing digital samples of a signal received at a receiver of a wireless communication system includes monitoring channel conditions and generating a channel indicator including at least one channel parameter by performing at least one of: estimating a channel mobility parameter and comparing it with a threshold; estimating a channel parameter of the energy of the channel outside a predefined temporal window, and comparing it with a threshold; estimating a channel temporal duration parameter and establishing if it meets predetermined criteria; estimating a channel-zero location parameter and establishing if it meets predetermined criteria; estimating a received-signal signal-to-disturbance power ratio, and comparing it to a threshold; estimating an estimated-channel-response signal-to-disturbance power ratio; estimating the degree of non-stationarity of the disturbance at the receiver input; and selecting one of a plurality of processing routines for processing the digital samples based on said