Abstract: The present invention relates to a method of improving the performance in bandwidth constrained communication systems while reducing the complexity of the equalizer used for information retrieval, as well as to improving the capacity of communication systems. These properties are achieved by appropriate information encoding, prior to signal shaping before transmission, whereas the equalizer complexity is reduced by applying the intersymbol interference shortening filter prior to the information retrieving equalization. A proper combination of the recounted elements is capable of providing a qualitatively improved and previously unsuspected performance, as compared to its constituent elements.

Abstract: The present invention relates to a method of improving the performance in bandwidth constrained communication systems while reducing the complexity of the equalizer used for information retrieval, as well as to improving the capacity of communication systems. The said properties are achieved by appropriate information encoding, prior to signal shaping before transmission, whereas the equalizer complexity is reduced by applying the intersymbol interference shortening filter prior to the information retrieving equalization. A proper combination of the recounted elements is capable of providing a qualitatively improved and previously unsuspected performance, as compared to its constituent elements.

Abstract: The present invention relates to a method of improving the performance in bandwidth constrained communication systems while reducing the complexity of the equalizer used for information retrieval, as well as to improving the capacity of communication systems. The said properties are achieved by appropriate information encoding, prior to signal shaping before transmission, whereas the equalizer complexity is reduced by applying the intersymbol interference shortening filter prior to the information retrieving equalization. A proper combination of the recounted elements is capable of providing a qualitatively improved and previously unsuspected performance, as compared to its constituent elements.

Abstract: The present invention relates to a method of improving the performance in bandwidth constrained communication systems while reducing the complexity of the equalizer used for information retrieval, as well as to improving the capacity of communication systems. The said properties are achieved by appropriate information encoding, prior to signal shaping before transmission, whereas the equalizer complexity is reduced by applying the intersymbol interference shortening filter prior to the information retrieving equalization. A proper combination of the recounted elements is capable of providing a qualitatively improved and previously unsuspected performance, as compared to its constituent elements.

Abstract: An iterative joint Minimum Mean Square Error (MMSE) decision feedback equalizer and turbo decoder includes a turbo decoder portion and a decision feedback equalizer (DFE) portion. The DFE receives input signals and processes these input signals to generate an estimated symbol sequence that is communicated to the turbo decoder portion. The estimated symbol sequence is also communicated to the feedback portion of the DFE. The feedback portion of the DFE includes a symbol-by-symbol detector and a feedback filter. The soft decoder output values generated by the turbo decoder portion are communicated to the feedback portion of the DFE and are combined with the coded output as log likelihood ratio values in a multipass, iterative fashion whereby the equalizer and decoder are linked via iterative feedback to provide communication performance enhancement.

Abstract: A method and apparatus for multichannel combining and equalization in a multichannel receiver is described. The receiver jointly performs diversity combining, equalization and synchronization. The method and apparatus of the present invention may be used to provide a reduced complexity adaptive multichannel receiver for use in a digital communication system.

Abstract: An underwater acoustic communications system utilizes phase coherent modulation and demodulation in which high data rates are achieved through the use of rapid Doppler removal, a specialized sample timing control technique and decision feedback equalization including feedforward and feedback equalizers. The combined use of these techniques drammatically increases data rates by one and sometimes two orders of magnitude over traditional FSK systems by sucessfully combating fading and multipath problems associated with a rapidly changing underwater acoustic channel that produce intersymbol interference and make timing optimization for the sampling of incomming data impossible.