
H-ARQ Relaying and H
2
-ARQ Relaying 79
Figure 3.6: Feedback channel.
conventional HARQ strategies based on DF only, the new relay system is able
to enjoy a certain level of flexibility and exhibits significant improvement in
FER.
In the next section, we focus on the hybrid CF/DF based H
2
-ARQ-
Relaying strategy, although the AF/DF one is also addressed briefly. Only
incremental redundancy (INR) based HARQ is considered and the proposed
strategies and their spectrum and energy efficiency analysis are the main top-
ics.
3.3.1 H
2
-ARQ Relaying Strategy
When retransmission protocols are considered, the same message is transmit-
ted until the destination successfully ...