"The drawbacks of both ARQ and FEC system could be overcome if the two error control schemes are combined. The combination of two basic error control scheme is referred to as Hybrid ARQ."

I have 2 questions: 1) As HARQ (at MAC layer) is used together with ARQ (t RLC layer), it means ARQ outperforms HARQ in terms of error detection capabilities, otherwise ARQ would have never been needed to be used after HARQ. But then one could wonder why HARQ was designed only with a part of ARQ error detection power and not with all, so that HARQ completely supersedes the ARQ. In other words what is the advantage of a solution in 2 steps: current less powerful HARQ followed by ARQ, compared to a solution with one step only using a powerful HARQ.

2) A system with FEC + ARQ combination is outperformed in all respects by a system with HARQ + ARQ combination?

Thanks, Rurre