Chapter 13

Retransmission Protocols


Retransmission functionality in three different protocol layers—hybrid ARQ, RLC, and PDCP—are discussed in this chapter. The timing of hybrid ARQ acknowledgments and the processing time is also described.


HARQ; hybrid ARQ; RLC; PDCP; CBG; soft combining; status reports; HARQ codebook; DAI; segmentation; in-sequence delivery

Transmissions over wireless channels are subject to errors, for example, due to variations in the received signal quality. To some degree, such variations can be counteracted through link adaptation as will be discussed in Chapter 14. However, receiver noise and unpredictable interference variations cannot be counteracted. Therefore, virtually all wireless communication systems ...

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