Block edge effects in iterative diversity reception

A method for processing signals representing data comprising:

• generating a plurality of individual signals, the plurality of individual signals being used to represent a common data sequence such that each of the individual signals corresponds to a data sequence that is a version of the common data sequence;
• separately transmitting the plurality of individual signals over different paths;
• wherein a composite signal comprising contributions from the plurality of individual signals is being processed by performing the steps of
• (a) for each individual signal, calculating soft values of a first type over a block of symbols by taking into account the composite signal and soft values of a second type, wherein for each symbol, a soft value of the first type is calculated for each possible symbol value of the symbol;
• (b) generating symbol outputs by taking into account the soft values of the first type from the different individual signals;
• (c) for each individual signal, calculating soft values of the second type over the block of symbols by taking into account the symbol outputs, wherein for each symbol, a soft value of the second type is calculated for each possible symbol value of the symbol;
• (d) feeding back the soft values of the second type for subsequent calculations of the soft values of the first type;
• (e) iteratively updating the soft values of the first type, the symbol outputs, and the soft values of the second type by repeating steps (a), (b), (c), and (d);
• (f) deriving data using the updated symbol outputs;
• and
• (g) wherein multiple blocks of symbols are so processed, and wherein adjacent blocks of symbols partially overlap one another.

An apparatus for deriving data from a composite signal by processing multiple blocks of symbols, the apparatus comprising:

• an input adapted to accept composite signal comprising contributions from a plurality of individual signals transmitted over different paths, the plurality of individual signals being used to represent a common data sequence such that each of the individual signals corresponds to a data sequence that is a version of the common data sequence;
• and
• a receiver structure coupled to the input, the receiver structure adapted for iterative processing involving
• (a) for each individual signal, calculating soft values of a first type over a block of symbols by taking into account the received composite signal and soft values of a second type, wherein for each symbol, a soft value of the first type is calculated for each possible symbol value of the symbol;
• (b) generating symbol outputs by taking into account the soft values of the first type from the different individual signals;
• (c) for each individual signal, calculating soft values of the second type over the block of symbols by taking into account the symbol outputs, wherein for each symbol, a soft value of the second type is calculated for each possible symbol value of the symbol;
• (d) feeding back the soft values of the second type for subsequent calculations of the soft values of the first type;
• (e) iteratively updating the soft values of the first type, the symbol outputs, and the soft values of the second type by repeating steps (a), (b), (c), and (d);
• (f) deriving data using the updated symbol outputs;
• and
• (g) wherein multiple blocks of symbols are so processed, and wherein adjacent blocks of symbols partially overlap one another.

An apparatus for processing signals representing data comprising:

• an input adapted to accept a common data sequence;
• a transmitter structure coupled to the input, the transmitter structure is adapted to generate a plurality of individual signals, the plurality of individual signals being used to represent the common data sequence such that each of the individual signals corresponds to a data sequence that is a version of the common data sequence;
• the transmitter structure further adapted to separately transmit the plurality of individual signals over different paths;
• wherein a composite signal comprising contributions from the plurality of individual signals is adapted to be processed iteratively by
• (a) for each individual signal, calculating soft values of a first type over a block of symbols by taking into account the received composite signal and soft values of a second type, wherein for each symbol, a soft value of the first type is calculated for each possible symbol value of the symbol;
• (b) generating symbol outputs by taking into account the soft values of the first type from the different individual signals;
• (c) for each individual signal, calculating soft values of the second type over the block of symbols by taking into account the symbol outputs, wherein for each symbol, a soft value of the second type is calculated for each possible symbol value of the symbol;
• (d) feeding back the soft values of the second type for subsequent calculations of the soft values of the first type;
• (e) iteratively updating the soft values of the first type, the symbol outputs, and the soft values of the second type by repeating steps (a), (b), (c), and (d);
• (f) deriving data using the updated symbol outputs;
• and
• (g) wherein multiple blocks of symbols are so processed, and wherein adjacent blocks of symbols partially overlap one another.

A system for deriving data from a composite signal by processing multiple blocks of symbols, the method comprising:

• (a) means for receiving a composite signal comprising contributions from a plurality of individual signals transmitted over different paths, the plurality of individual signals being used to represent a common data sequence such that each of the individual signals corresponds to a data sequence that is a version of the common data sequence;
• (b) means for, for each individual signal, calculating soft values of a first type over a block of symbols by taking into account the received composite signal and soft values of a second type, wherein for each symbol, a soft value of the first type is calculated for each possible symbol value of the symbol;
• (c) means for generating symbol outputs by taking into account the soft values of the first type from the different individual signals;
• (d) means for, for each individual signal, calculating soft values of the second type over the block of symbols by taking into account the symbol outputs, wherein for each symbol, a soft value of the second type is calculated for each possible symbol value of the symbol;
• (e) means for feeding back the soft values of the second type for subsequent calculations of the soft values of the first type;
• (f) means for iteratively updating the soft values of the first type, the symbol outputs, and the soft values of the second type by repeating steps (b), (c), (d), and (e);
• (g) means for deriving data using the updated symbol outputs;
• and
• (h) wherein multiple blocks of symbols are so processed, and wherein adjacent blocks of symbols partially overlap one another.