Based on the IEEE 802.11n standard, frame aggregation is considered one of the major factors to improve system performance of wireless local area networks (WLANs) from the medium access control (MAC) perspective. In order to fulfill the requirements of high throughput performance, feasible design of automatic repeat request (ARQ) mechanisms becomes important for providing reliable data transmission. In this paper, two MAC-defined ARQ schemes are proposed to consider the effect of frame aggregation for the enhancement of network throughput. An aggregated selective repeat ARQ (ASR-ARQ) algorithm is proposed, which incorporates the conventional selective repeat ARQ scheme with the consideration of frame aggregation. On the other hand, the aggregated hybrid ARQ (AH-ARQ) protocol is proposed to further enhance throughput performance by adopting the Reed-Solomon block code as the forward error correction (FEC) scheme. Novel analytical models based on the signal flow graph are established in order to realize the retransmission behaviors of both schemes. Simulations are conducted to validate and compare the proposed ARQ mechanisms with existing schemes based on service time distribution. Numerical results show that the proposed AH-ARQ protocol outperforms the other retransmission schemes owing to its effective utilization of FEC mechanism.

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How to provide low energy consumption and high packet delivery ratio are considered the major issues in the protocol design for the wireless multihop networks. The main focus of this paper is to reduce the number of data transmissions such that the energy consumption can be decreased. In the wired networks, the Steiner-Tree is regarded as an optimal approach to construct the multicast structure for specific senders and receivers. However, it is considered an NP-Hard problem for achieving the minimum cost multicast tree under the wireless broadcast environment. In this paper, an Energy-Conserving Multicast Routing (ECMR) protocol is proposed as a heuristic scheme to reduce the number of relaying nodes for the construction of the multicast mesh. Moreover, the proposed algorithm is implemented on an ARM-based embedded platform for performance evaluation. Comparing with the existing multicast routing protocol, the experimental results show that the proposed ECMR scheme can provide better energy conservation while the packet delivery ratio is still preserved.Index Terms-Wireless multihop networks, multicast routing, protocol implementation.

How to provide low energy consumption and high packet delivery ratio are considered the major issues in the protocol design for the wireless multihop networks. The main focus of this paper is to reduce the number of data transmissions such that the energy consumption can be decreased. In the wired networks, the Steiner-Tree is regarded as an optimal approach to construct the multicast structure for specific senders and receivers. However, it is considered an NP-Hard problem for achieving the minimum cost multicast tree under the wireless broadcast environment. In this paper, an Energy-Conserving Multicast Routing (ECMR) protocol is proposed as a heuristic scheme to reduce the number of relaying nodes for the construction of the multicast mesh. Moreover, the proposed algorithm is implemented on an ARM-based embedded platform for performance evaluation. Comparing with the existing multicast routing protocol, the experimental results show that the proposed ECMR scheme can provide better energy conservation while the packet delivery ratio is still preserved.