Patent ID: 7373582

Claim:
An apparatus for turbo decoding using a variable window size, comprising at least one constituent decoder, the at least one constituent decoder comprising: a control logic block for receiving information including a code rate of received data bits and a data block size, adjusting a window size according to the code rate information, and computing an initial delay; a plurality of delta metric blocks for computing delta metrics from input data bits of the block size, the delta metrics representing a transition probability for a path from a state to another state, respectively; an alpha metric block for receiving a delta metric in synchronization with the initial delay, and computing an alpha metric representing a forward state transition probability in each state; one or more beta metric blocks for receiving delta metrics according to the adjusted window size, and computing beta metrics representing a backward state transition probability in each state, respectively; and a log likelihood ratio (LLR) block for receiving the alpha metric and the beta metrics in synchronization with the initial delay, and computing LLR values for symbols in an ending state.