A bit-by-bit interleaver is a mechanism used in digital communication and information processing to reorder individual bits within a data stream. The interleaving process rearranges the sequence of bits to enhance the performance of error correction and detection mechanisms. In a bit-by-bit interleaver, each bit of the original data stream is individually interleaved, typically following a specific pattern or algorithm. This differs from other interleaving techniques that may operate on larger chunks of data, such as bytes or symbols. The primary purpose of bit-by-bit interleaving is to spread out errors that may occur in consecutive bits due to noise or interference during transmission. By dispersing errors, it helps error correction codes to work more effectively, improving the overall reliability of data transmission.