Low-density parity-check (LDPC) codes are a type of error-correcting code that can be used to transmit data reliably over a noisy communication channel. LDPC codes have gained popularity in recent years due to their excellent error-correction performance and low decoding complexity. LDPC codes are structured as sparse bipartite graphs, with variable nodes representing the bits of the transmitted message and check nodes representing the parity constraints that the transmitted message must satisfy. The decoding process involves passing messages between variable nodes and check nodes in order to iteratively improve the estimate of the transmitted message. Research in the area of LDPC codes focuses on optimizing the design of LDPC codes for specific communication scenarios, improving decoding algorithms to achieve better error-correction performance, and exploring applications of LDPC codes in various communication systems. Overall, LDPC codes are a versatile and powerful tool in modern coding theory and communication engineering.