SRA-MSDU: Enhanced A-MSDU frame aggregation with selective retransmission in 802.11n wireless networks

Abstract

The main goal of the IEEE 802.11n standard is to achieve more than 100 Mbps of throughput at the MAC service access point. This high throughput has been achieved via many enhancements in both the physical and MAC layers. One of the MAC enhancements is the frame aggregation in which multiple frames are concatenated into a single large frame before being transmitted. The 802.11n MAC layer defines two types of aggregation, aggregate MAC service data unit (A-MSDU) and aggregate MAC protocol data unit (A-MPDU). The A-MPDU outperforms A-MSDU due to its large aggregation size and the subframes retransmission in erroneous channels. However, in error free channels and under the same aggregation size the A-MSDU performs better than the A-MPDU due to its smaller headers. Thus, adding a selective retransmission capability to the A-MSDU would improve the system performance. In this paper, we have proposed an MSDU frame aggregation scheme that enables selective retransmission at the MSDU level without altering the original MAC header. In this proposed scheme an implicit sequence control mechanism has been introduced in order to keep the frames in sequence and preserve their correct order at the receiver side. The results show that the proposed scheme improves the system performance in terms of throughput and delay even under highly erroneous channels.

Impact of IEEE 802.11n/ac PHY/MAC High Throughput Enhancements on Transport and Application Protocols—A Survey

“…The MIMO-OFDM increases network throughput and range of communications significantly due to the use of multiple antennas. MIMO is used in some existing works such as [33]- [36] without evaluating TCP/UDP throughput directly. These works can be extended to find impact of MIMO over upper layer throughput.…”

Design a New Bidirectional Transmission Protocol to Improve the Performance of MAC Layer Based on Very High Speed WLANs

“…• The same TID value must be acquired by all MSDUs • Capacity of A-MSDU needs to be appropriate according to the maximal capacity of its integral elements • Identical Receiver Address (RA) and Transmitter Address (TA) must with Destination Address (DA) and Sender Address (SA) (Skordoulis et al, 2008;Saif and Othman, 2013) Broadcasting or multicasting, therefore, is prevented. However, the main weakness of employing A-MSDU is represented by the under networks immune to errors.…”

Scheduler Algorithm for IEEE802.11n Wireless LANs

“…Saif. [9], introduced an MSDU frame aggregation called SRA-MSDU aggregation scheme to reduce the headers of the subframes and supports the retransmission of the corrupted MSDUs at the MSDU level. By incorporating control fields to the subframe header in order to enable a subframe integrity check and selective retransmission with the MAC header of A-MSDU frame being unchangeable as in Fig.…”

“…The header of the received MSDUs from the upper layer has to be modified as suggested in [9] by adding control fields to the subframe header in order to enable retransmission and to create the MAC frame which in turn will be ready to aggregate. The received MSDUs from the upper layer are queued in the transmitting queue based on their priorities and arrival time.…”