The ever-growing popularity of Wireless Local Area Networks (WLANs) in home, public, and work environments is fuelling the need for WLANs that can accommodate more stations, each with higher throughput. This typically results in WLANs containing a larger number of heterogeneous devices, making the prediction of the network's behavior and its efficient configuration an even more elaborate problem. In this paper, we propose a Markovian model that predicts the throughput achieved by each Access Point (AP) of the WLAN as a function of the network's topology and the AP's throughput demands. By means of simulation, we show that our model achieves mean relative errors of around 10% for networks of different sizes and with diverse node configurations. The model is adapted to the specification of IEEE 802.11 standards that implement channel bonding, namely 802.11n/ac/ax, and as such it can be used to provide insight into issues of channel assignment when using channel bonding. We derive guidelines on the best practice in static channel bonding given a performance metric and for different node characteristics such as the Modulation and Coding Scheme (MCS) indexes, frame aggregation rates, saturation levels, and network topologies. We then put our findings to the test by identifying the optimal channel bonding combination in an 802.11ac WLAN containing nodes with diverse characteristics. We conclude that the optimal solution is highly dependent on the particular network configuration. However, we find that, in general, larger channels are better suited for throughput maximization and smaller (and separate) channels render higher fairness.

WLANs (Wireless Local Area Networks) based on the IEEE 802.11 standard have become ubiquitous in our daily lives. We typically augment the number of APs (Access Points) within a WLAN to extend its coverage and transmission capacity. This leads to network densification, which in turn demands some form of coordination between APs so as to avoid potential misconfigurations. In this paper, we describe a performance modeling method that can provide guidance for configuring WLANs and be used as a decision-support tool by a network architect or as an algorithm embedded within a WLAN controller. The proposed approach estimates the attained throughput of each AP, as a function of the WLAN's conflict graph, the AP loads, the frame sizes, and the link transmission rates. Our modeling approach employs a Divide-and-Conquer strategy which breaks down the original problem into multiple sub-problems, whose solutions are then combined to provide the solution to the original problem. We conducted extensive simulation experiments using the ns-3 simulator that show the model's accuracy is generally good with relative errors typically less than 10%. We then explore two issues of WLAN configuration: choosing a channel allocation for the APs and enabling frame aggregation on APs.(AP) of a WLAN, their variety has greatly expanded, comprising desktop and laptop computers, IP phones, smartphones, digital media players, etc.WLANs are typically based on the IEEE 802.11 standard [1]. In order to meet the increasing needs of WLAN users, IEEE 802.11 has undergone several amendments, mostly aimed at strengthening its performance and security. In particular MAC (Medium Access Control) and PHY (Physical) functions have been enhanced. Indeed, transmission technologies, defining the PHY layer of IEEE 802.11, have significantly evolved over the years using e.g., wider channels, higher-order modulations, multiple-input multiple-output antennas (MIMO). Maybe to a lesser extent, the MAC layer has also undergone some transformations with the possibility of using the Request to Send / Clear to Send mechanism (RTS/CTS), smaller mandatory waiting periods before transmissions, as well as frame aggregation and block acknowledgment in the latest amendments of IEEE 802.11.In order to extend the coverage and the available transmission capacity of WLANs, network architects may augment the number of APs within a WLAN. This network densification comes with a growing complexity in the WLAN management. Indeed, a WLAN with several APs requires some form of coordination between its APs so as to avoid potential misconfigurations that could lead to an inefficient use of radio resources, poor performance and/or unfairness between users. For instance, coordination efforts can pertain to the selection of a radio channel for each AP (for mitigating interferences from neighboring APs) as well as to the association of user devices with the APs (for balancing the load among APs). Some proprietary and commercial solutions implement such mechanisms. Among others, CAPWAP and 802....

WLANs (Wireless Local Area Networks) have become ubiquitous in our everyday life, and are mostly based on IEEE 802.11 standards. In this paper, we consider the performance evaluation of an arbitrary-topology unsaturated network based on the IEEE 802.11 DCF. We present a conflict graphbased modeling approach to discover the attainable throughput of each node. Our model consists of a single Markov chain which aims at describing, at a high-level of abstraction, the current state of the entire wireless network. Owing to its low complexity, our approach is simple to implement, can cope with medium sized networks, and its execution speed is fast. We validate its accuracy against a discrete-event simulator. Results show that our approach is typically accurate, with associated relative errors generally less than 15%, and that it captures complex phenomena such as node starvation. We investigate two potential applications of our proposed approach in which, starting with a given network, we improve its performance in terms of overall throughput or fairness by throttling the throughput demand of a node, or by turning a node off altogether.