Patent ID: 9490905
Filing Date: 2016-11-08
CPC Classification: H04B,H04L

Claim Text:
1. An apparatus operable to determine estimates for transmitted symbols from received symbols of an optical signal affected by cross-polarization Modulation, XpolM, the apparatus comprising: a grouping module operable to group two or more subsequent received symbols from the optical signal into a group of received symbols; an estimation module operable to estimate an optical channel based on the group of received symbols and a hypothesis on the transmitted symbols; a determination module operable to determine a reliability measure for a combination of the group of received symbols, the channel estimate, and the hypothesis, and further operable to determine the estimates for the transmitted symbols based on reliability measures for multiple hypotheses on the transmitted symbols; wherein a transmission of transmit symbols is organized in repetitive symbol intervals and wherein two transmit symbols are transmitted per symbol interval using different polarizations of the optical signal, and wherein the apparatus is operable to receive two received symbols per symbol interval and the grouping module is operable to group received symbols of two or more symbol intervals into the group of received symbols; and wherein the grouping module is operable to group received symbols from symbol intervals corresponding to a time period, which is less than a coherence time of the optical channel, into the group of received symbols.