Data storage device including a recording channel, a detector, and a noise prediction circuit, and method of processing a signal in a data storage device

1. A data storage device comprising:

a recording channel configured to carry a signal;

a detector configured to detect the signal from the recording channel;

a noise prediction circuit configured to predict noise affecting the recording channel and the detected signal based on a noisy channel model; and

a decoder configured to decode the detected signal based on the predicted noise;

wherein the detector and the decoder form a joint detector/decoder circuit; and

wherein the noisy channel model comprises at least one of:

a single channel graph model, wherein the joint detector/decoder circuit has a layered structure comprising check nodes of low-density parity-check codes, low-density parity-check bit nodes, and channel check nodes; or

a concatenated channel graph model, wherein the joint detector/decoder circuit has a layered structure comprising a serial concatenation of a rowwise binary channel graph, a columnwise non-binary channel graph, and a low-density parity-check code graph.

2. The data storage device of claim 1 , wherein the joint detector/decoder circuit is a low density parity check joint detector/decoder circuit.

3. The data storage device of claim 1 , wherein the noise prediction circuit comprises a data dependent noise prediction circuit.

4. The data storage device of claim 1 , wherein the noisy channel model comprises an equalized channel model.

5. The data storage device of claim 1 , further comprising a quantizer arranged to quantize the signal from the recording channel.

6. The data storage device of claim 1 , further comprising an encoder arranged to encode user data for storing in the recording medium.

7. A method of processing a signal in a data storage device, the method comprising:

providing a recording channel;

detecting a signal from the recording channel;

predicting noise affecting the recording channel and the detected signal based on a noisy channel model; and

decoding the detected signal based on the predicted noise;

wherein detecting a signal from the recording channel and decoding the detected signal comprise jointly detecting and decoding the signal;

wherein detecting and decoding the signal is based on at least one of:

a message-passing algorithm operating on a layered structure comprising low-density parity-check check nodes, low-density parity-check bit nodes, and channel check nodes; or

a message-passing algorithm operating on a layered structure comprising a serial concatenation of a rowwise binary channel graph, a columnwise non-binary channel graph, and a low-density parity-check code graph.

8. The method of claim 7 , wherein predicting noise comprises predicting data dependent noise.

9. The method of claim 7 , further comprising quantizing the signal from the recording channel.

10. The method of claim 7 , further comprising encoding user data for storing in the recording medium.