1. A method comprising: receiving a codeword generated based on an LDPC code; determining soft information based on the received codeword; generating symbol node messages and parity check node messages based on the soft information; and iteratively processing the symbol node messages and the parity check node messages, wherein each iteration comprises: updating one or more symbol node messages in a first memory block simultaneously with updating one or more parity check node messages in a second memory block in a first time interval of the iteration, updating one or more symbol node messages in the second memory block simultaneously with updating one or more parity check node messages in the first memory block in a second time interval of the iteration occurring after the first time interval of the iteration, and updating, during a third time interval occurring after the first time interval and the second time interval, connector circulant messages in a connector circulant memory block located adjacent to the first memory block.