Dynamic AMPDU adaptation method for airtime fairness in channel bondingready WLANs Channel bonding is a technology to increase the transmission rate by bundling and using multiple continuous channels. However, the communication performance is likely to degrade frequently due to the channel competition caused by the rapid increase of the wireless LAN devices. Dynamic channel bonding is expected to become the mainstream in the future from the viewpoint of efficient channel utilization even under the severe competitive condition. However, since the implementation of the dynamic channel bonding to real PC and simulator is in the preliminary stage, the detailed performance investigation has not been carried out. None of existing studies examines the performance of the dynamic channel bonding at the frame level with CSMACA functions under the diverse channel competition condition. In this study, we first examine the performance of the dynamic channel bonding with CSMACA functions through theoretical approach (2 MM1K) from the view point of frame level. In addition, we then implement the channel bonding mechanism into the Scenargie simulator and then verify its effectiveness through the comparison between simulation results and theoretical ones. Simulation results show that the dynamic channel bonding is suffering from the performance degradation due to the performance anomaly problem caused by the airtime unfairness, we thus propose a dynamic AMPDU adaptation method. We showed that our proposed method can maximize throughput while achieving airtime fairness, irrespective of different patterns of channel competition.

Fair and efficient resource allocation in IEEE 802.11ah WLAN with heterogeneous data rates Abstract   For dense wireless LANs (WLANs), IEEE 802.11ah has specified restricted access window (RAW) as the channel access scheme. Here the competing stations (STAs) are divided into groups and STAs belonging to each group attempt to access the channel during their designated RAW slot by invoking the distributed coordination function (DCF) protocol. This paper describes an analytical model to evaluate the throughput performance of IEEE 802.11ah WLAN, when STAs use distinct data rates and the RAW mechanism is implemented for medium sharing. When STAs are grouped randomly (i.e., without considering their data rates), a group will contain STAs operating at distinct data rates. Since all these STAs simultaneously contend for channel access based on DCF protocol, the throughput of high data rate STAs are downequalized to that of lower data rate STAs; thus the aggregate network throughput is degraded significantly. To resolve the resulting performance anomaly problem, we consider data rate based grouping where STAs operating at the same data rate are grouped together. We describe an algorithm for implementing data rate based grouping at the access point (AP). Further, we describe an analytical procedure to find the network throughput under data rate based grouping. Through numerical and experimental investigations, we establish that data rate based grouping can significantly improve the aggregate network throughput performance, as compared to the conventional random grouping strategy. Further, we use Jainxe2x80x99s fairness index (JFI) to establish that data rate based grouping can also provide fair resource allocation among the STAs operating at distinct data rates, by ensuring that all the competing STAs in the network achieve throughput proportional to their data rates.