| 摘要 |
The present invention provides an apparatus and method for universal decoding of both feedforward codes and feedback codes, such as decoding of a 512-state feedforward code, a 32-state feedback code and 8-state feedback code. Utilizing parallel processing, the present invention determines, for each current state of a feedforward or a feedback code, its most likely previous states, resulting in a determination of a terminating state and a penultimate terminating state. From the penultimate terminating state and terminating state, associated subset bits are determined. In the preferred embodiment, the subset bits are determined by re-encoding the most significant bit of the penultimate terminating state in an encoder having a current state equal to the terminating state. Utilizing an equalized, received signal, a closest signaling point, with an associated index, is selected from a subset of a signaling constellation corresponding to the associated subset bits. The decoded higher significant bits are determined as equal to the corresponding higher significant bits of the associated index. For a feedforward code, the decoded least significant input bit is determined as equal to the most significant bit of the penultimate terminating state, while for a feedback code, the decoded input bit is determined as equal to the most significant subset bit.
|
