Abstract: A method of asymmetrical forward error correction for a communication link having two communication directions, comprising a first type of forward error correction method in a first direction of the communication link and a second type of forward error correction method in a second direction of the communication link, where the first and second types of forward error correction methods are different.

Abstract: The encoder of a communication device is configurable such that the encoder may operate in any of a variety of forward error correction modes. Further, for each mode, a variety of encoding parameters may be configured. The configurability of forward error correction modes and/or parameters enables communication devices to perform interactive configuration processes, whereby a communicating device specifies the type of forward error correction that the other is to perform. This configuration may be bidirectional, such that each device selects the forward error correction provided by the other. Each device may further configure its decoder to decode the forward error correction mode that it has selected for the other communication device. In other embodiments two communicating devices may implement two different modes of forward error correction.

Abstract: A non-separable symbol constellation may comprise constituent constellations having separable I and Q. Such a non-separable constellation may be decoded with the efficiency of a separable constellation by decoding for each of the constituent constellations individually. In a transmitter, transmit data may be mapped to symbols by selecting a constituent constellation and I and Q values for a symbol to be transmitted. In a receiver, decoders may decode for each constituent individually.

Abstract: A transmitter produces a modulated signal with forward error correction from an information bit stream in a QAM transmitter. The transmitter produces parity bit streams that correspond to an inputted information bit stream using first and second concatenated coders interconnected by an interleaver. Subsets of the first and second parity bit streams are selected in accordance with a puncturing pattern. A variety of novel puncturing patterns providing various coding rates for various constellations are disclosed. The transmitter combines the selected subsets of said first and second parity bit streams with said information bit stream. A QAM symbol stream is produced by mapping a first subset of the combined bit streams to an I dimension and mapping a second subset of the combined bit streams to a Q dimension. The QAM symbol stream is modulated to produce a modulated signal that is transmitted over a communication link. A complementary receiver is also disclosed.

Abstract: In a receiver, an outer decoder in an inner/outer decoder scheme receives bit error information or bit error probability information from an inner decoder rather than being generated internally by the outer decoder. The inner decoder may be a soft-decision decoder that provides bit error probabilities, or a sum-product decoder that provides bit error information. Thus, unlike conventional outer decoders, the outer decoder does not require a conventional first stage for determining errors in the output bit stream of the inner decoder based on the bits of the output bit stream themselves. A related transmitter uses a sum-product inner decoder in conjunction with an outer decoder.