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Multi-Channel Wi-Fi experiments are quickly becoming more common and relevant as Wi-Fi deployments have become extremely popular and dense in recent years. There are many simulation tools available for Wi-Fi simulation, but few are widely used, and some are not designed specifically with wireless in mind. In this paper, the NS3 environment is recognized as a promising tool for which for this type...
We describe performance results for a Dynamic Spectrum Management (DSM) Platform, including over-the-air data captured outdoors near our Melville, NY facility and in an indoor office environment. The DSM system configuration used to generate the results, and the flexibility of the DSM system that allows it to operate in different bandwidth TV channels are presented. The results include data throughput,...
The IEEE 802.11 standardization group has recently ratified 802.11ac as the newest major amendment of the 802.11 family of Wi-Fi standards. While 802.11ac has specified a number of improvements over 802.11n such as: (i) 8 spatial streams (ii) mandatory bandwidth of 80 MHz and (iii) multi-user MIMO on the downlink, these improvements mostly target to improve the per-link throughput, and in case of...
In future's high density Wireless Local Area Networks (WLANs), to improve the overall throughput, we envision the optimization of the MAC protocols and mechanisms. Traditionally, it's clear in the literature that Transmit Power Control (TPC) is chosen as one of the most powerful tools for optimizing MAC protocols. However, the TPC is not always possible to implement due to hardware and licensing limitations...
Wireless communications are becoming increasingly appealing for many application areas in industrial environments, including control systems at the shop-floor. IEEE 802.11 resembles Ethernet closely and, in the newest versions, it manages to provide similar throughput. Unfortunately, it fails in ensuring a comparable degree of reliability, mostly because its physical layer is quite sensitive to interference...
Wireless mesh networks (WMNs) suffer from scalability, performance degradation and service disruption issues due to overwhelming multi-hop co-channel interference, unscrupulous channel utilization and inherent network mobility. We propose a set of efficient distributed dynamic channel access scheduling protocols, called DDCS, based on distributed clustering and dynamic Latin squares for WMN systems...
The demand of mobile traffic increases tremendously as various Internet services are provided to mobile phones and computing devices, making mobile carriers to increase capacity of cellular network. Since current cell towers and auxiliary devices cannot carry excessive amount of traffic, several mobile carriers try to install low cost wireless equipments such as Wi-Fi access points (AP) so that some...
Bluetooth and IEEE 802.11 (Wi-Fi) are two of the most popular communication standards which define a physical and a MAC layers for wireless transmissions and operate on 2.4 GHz ISM band. To avoid the rich interference existed in ISM band, Bluetooth adopts a time-slotted frequency-hopping spread-spectrum scheme, preventing from the interference for a long time on specific channel. However, the coexistence...
In this paper we study a transmission power-tune/control problem in the context of 802.11 Wireless Local Area Networks (WLANs) with multiple (and possibly densely deployed) access points (APs). Previous studies on power control tend to focus on one aspect of the control, either its effect on transmission capacity (PHY layer) assuming simultaneous transmissions, or its effect on contention order (MAC...
We consider uplink WiFi data offloading in a heterogeneous network consisting of one LTE macrocell and one overlaid 802.11n WiFi hotspot to maximize the minimum energy efficiency (EE) of the users. We propose a closed-form expression to compute Nw, i.e., the number of offloaded users, and then offload the data traffic of Nw users with the lowest received SINR at the cellular base station (BS) to the...
Wireless LANs based on the IEEE 802.11 standard are one of the most commonplace indoor wireless access solutions. As the ever growing demand for data consumption necessitates higher rates and volumes, it is fairly common to observe more and more WLANs being deployed in close proximity to each other. As distances between WLAN installations diminish, the access points (APs) and stations (STAs) in these...
In order to reduce energy wastefully consumed by WiFi device, Radio-On-Demand Networks (ROD) has been proposed, which offers wireless access in an on-demand manner. Each WiFi device in ROD is equipped with a low-power wake-up receiver which is capable of detecting the length of frames observed over WiFi channels through envelope detection and on-off-keying (OOK) processing. Once the wake-up receiver...
We1 propose two methods for the detection of RF interference. The first one is for the detection of the interferences from microwave ovens, and the second one is for Wi-Fi and Bluetooth signals. The motivation of this work is to design a system for reliable wireless communication. Specifically, the systems equipped with interference detectors will be able to choose the appropriate time intervals to...
Dynamic transmit-power control (DTPC) is critical to improve spectral efficiency and reduce interference in wireless local area networks (WLANs). DTPC schemes typically use signal-to-noise-ratio (SNR) information and require exchange of information between transmitters and receivers. However, that is not always easy to implement in actual WLAN deployments. In this paper, we present a simple but novel...
In a distributed control wireless ad-hoc network, network performance is significantly effected by multi-user interference. In such networks, transmit power control can enhance the energy usage as well as the QoS performance. Although, the effects of hidden/exposed terminals on the system throughput in wireless ad-hoc networks have been studied extensively, the IEEE 802.11 with variable transmit power...
Frequently, client-side wireless devices have a view of multiple WiFi access points, whether from open residential and commercial networks, corporate networks, or mesh networks. Given the increasing number of radios and antennas in today's wireless devices, residual capacity from these multiple APs could be leveraged if client devices communicate with multiple APs simultaneously. In this paper, we...
Coordination among users is an indispensable part in wireless networks for efficient medium access. Alone with the rapid increase of transmission rate, however, coordination time becomes insufferable. We present AFD, namely asymmetric full duplex, to achieve high coordination efficiency at nearly zero overhead. In AFD, channel contention is performed simultaneously with data transmission. We propose...
Slow Internet connectivity is often caused by poor Wi-Fi performance. The main reasons of such performance degradation include channel contention and non-Wi-Fi interference. Although these problem sources can be easily removed in many cases once they are discovered, it is difficult for end users to identify the sources of such interference. We investigated the characteristics of different sources...
Co-existing in the unlicensed ISM band, ZigBee transmissions can be significantly interfered by WiFi. Although several approaches recently are proposed to enable ZigBee transmission under WiFi interference, the ZigBee throughput still decreases to zero when WiFi throughput (generated by D-ITG) is over 8Mbps. In this paper, we propose a real-time (< 5ms) adaptive transmission (RAT) scheme to efficiently...
One of the main problems affecting reliable transmission in wireless body sensor networks based on IEEE 802.15.4 is interference caused by sharing the unlicensed 2.4 GHz ISM band with other technologies such as Wifi. One possible approach to deal with this problem is to allow a body sensor network to change its operating frequency and its transmit power in response to changes in the observed interference...
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