Abstract: System, including method, apparatus, and computer-readable media, for evaluating client status for a likelihood of churn. Client data may be received, with the client data representing events from a set of different event types performed by clients. Parameters of a statistical model that describes client behavior may be estimated using a computer and based on the client data. A churn type of event may be encoded in the statistical model as an absorbing state of a stochastic process, with a time of transition to the absorbing state modeled as being infinite. At least one of the parameters may correspond to the churn type of event. A likelihood of churn may be calculated for a plurality of the clients at one or more time points using the statistical model and its estimated parameters.

Abstract: System, including method, apparatus, and computer-readable media, for evaluating client status for a likelihood of churn. Client data may be received, with the client data representing events from a set of different event types performed by clients. Parameters of a statistical model that describes client behavior may be estimated using a computer and based on the client data. A churn type of event may be encoded in the statistical model as an absorbing state of a stochastic process, with a time of transition to the absorbing state modeled as being infinite. At least one of the parameters may correspond to the churn type of event. A likelihood of churn may be calculated for a plurality of the clients at one or more time points using the statistical model and its estimated parameters.

Abstract: Multiple-access codes are generated using an asymptotically optimal decoding algorithm, such as the Viterbi algorithm. A trellis may be constructed using a number of desired users, at least one code length, and a number of code-chip parameters. A fitness function is derived from a mathematical relationship between the multiple-access codes, and may include some measure of correlation of the codes. The multiple-access codes correspond to paths having optimal path metrics derived from the fitness function. Multiple iterations through the trellis may be performed to refine a selection of multiple-access codes.

Abstract: Spatial subchannel codes for wireless devices operating in a cooperative antenna array are generated using an asymptotically optimal decoding algorithm, such as a trellis-exploration algorithm similar to the Viterbi algorithm. A trellis may be constructed using a number of desired subchannels, at least one code length, and a number of code-chip parameters. A fitness function is derived from a mathematical relationship between codes, and may include some measure of correlation of the codes. The selected codes correspond to paths having optimal path metrics derived from the fitness function. Multiple iterations through the trellis may be performed to refine a selection of the codes.

Abstract: Precoding codes for MIMO transmitters are generated using an asymptotically optimal decoding algorithm, such as a trellis-exploration algorithm similar to the Viterbi algorithm. A trellis may be constructed using a number of desired subchannels, at least one code length, and a number of code-chip parameters. A fitness function is derived from a mathematical relationship between codes, and may include some measure of correlation of the codes. The selected codes correspond to paths having optimal path metrics derived from the fitness function. Multiple iterations through the trellis may be performed to refine a selection of the codes.