PTER correctly decoded, then the decoded codeword is this theorem is useful in understanding the theoretical accepted. Otherwise, a retransmission is requested for performance bounds for the communication of data over the codeword. an unreliable channel, it does not explain how a practical communication system should be designed. Practical 3.4.5.2.2 Type-II hybrid-ARQ protocols system design should consider source coding, channel The basic difference between a type-I hybrid ARQ control, and modulation. State-of-the-art channel coding protocol and a type-II hybrid ARQ protocol is that in the techniques are overviewed in the second part of the latter the transmitter sends additional parity bits instead chapter. The main message is that channel coding of the whole codeword when it receives a retransmission techniques, in particular Turbo codes and LDPC codes, request for this codeword. The following example [50] have reached a level of maturity that allows them to illustrates the method. An (n, k) MDS code C is used to achieve performance close to the theoretical bounds encode the information block. The resulting codeword is announced by Shannon. Another important achievement split in two. The first half can be seen as a codeword C1 in the area of channel coding is development of the class from an (n/2, code C1 and the second one as a codeword of digital fountain codes for protection against packet C2 from an (n/2, k) code C2. Here the two codes C1 and C2 loss. The third part of the chapter discussed hierarchical are obtained by puncturing the code C. The transmitter modulation, an emerging modulation technique for starts by sending C1. If the received word y1 cannot be digital video broadcasting. The last part of the chapter correctly decoded, a retransmission is requested. The gave a brief survey of error control techniques that rely transmitter then sends the codeword C2, which is received on data retransmission. These techniques, which require as y2. The receiver concatenates y1 and y2 and uses the a two-way cha