Abstract: A method for estimating the phase of a modulated complex optical signal, according to which, the phase of the signal is isolated and the complex amplitude of the signal is digitized by a block of P samples. An adaptive filter minimizes phase-error between the phase of the received symbol and the phase of a sample, rotated by a phase correction factor, by iteratively performing a Block-Wise Phase LMS estimation on the samples using a step size parameter. During each iteration, the resulting correction factor consists of the sum of the estimated errors multiplied by this parameter, and the correction factor of previous iteration, which is updated, until obtaining the final correction factor from the last iteration. The samples constituting the received signal are recovered by adding the most updated correction factor to the phase of each sample and performing a decision regarding the phase of each sample.

Abstract: A method for estimating the phase of a modulated complex optical signal, according to which, the phase of the signal is isolated and the complex amplitude of the signal is digitized by a block of P samples. An adaptive filter minimizes phase-error between the phase of the received symbol and the phase of a sample, rotated by a phase correction factor, by iteratively performing a Block-Wise Phase LMS estimation on the samples using a step size parameter. During each iteration, the resulting correction factor consists of the sum of the estimated errors multiplied by this parameter, and the correction factor of previous iteration, which is updated, until obtaining the final correction factor from the last iteration. The samples constituting the received signal are recovered by adding the most updated correction factor to the phase of each sample and performing a decision regarding the phase of each sample.

Abstract: In a method and system for scheduling unicast and multicast data packets associated a weight value reflecting the urgency of each queue in a set of available input nodes to transmit its queued cells is computed. If the highest weight queue in each input node is unicast, a request containing the weight of the queue is sent to a single output node relating to the highest weight queue. Otherwise, a request containing the weight of the queue is sent to one or more output nodes relating to the multicast queue. A grant is sent to the highest weight input node sending a request for a specific output node. Input nodes relating to unicast queues are removed from consideration in successive iterations. Input nodes relating to multicast queues may compete in successive iterations but only from the same multicast queue.

Abstract: A method and apparatus for establishing queue priorities for selecting one queue from at least two queues each containing items to be serviced, wherein a metric is determined for each queue by estimating the aggregate waiting time associated with all of the items in the respective queue, and the estimated aggregate waiting time is used to form a priority metric.