Hybrid type-II ARQ/AMS and scheduling using channel prediction for downlink packet transmission and fading channels
Sorour Falahati, Nilo Casimiro Ericsson, Arne Svensson, Anders Åhlén · Chalmers Research (Chalmers University of Technology) · 2001
In this paper, we propose a system suitable for Internet Protocols (IP) which consists of a hybrid type-II Automatic Repeat reQuest (ARQ) scheme combined with an Adaptive Modulation System (AMS) and a time-slot scheduler supplied by channel predictions, referred to as predictive HARQ-II/AMS. The performance of the system in a downlink for fast fading channels is investigated through simulations where in particular, BER, throughput and delay performance are studied. The proposed system is compared to two modified systems where one does not utilize Forward Error Correction/ARQ (FEC/ARQ) at link layer (referred to as predictive AMS) while the other one has no access to the channel prediction (referred to as blind HARQ-II/AMS). The results show that with perfect channel prediction both predictive AMS and HARQII/AMS satisfy the Quality of Service (QoS) requirements with some advantages to the former in terms of efficient usage of channel capacity. However, when imperfect channel prediction is utilized only our proposed system meets the users demands.