The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Although static mesh networks lack mobility, yet research shows that route breakages are quite frequent for reactive protocols in 802.11-based static mesh networks. In 802.11, a link is considered broken if a fixed number of consecutive transmission attempts fail at link-layer. However, transmissions failures can be temporary and may occur due a number of reasons including collisions on the channel...
Current market trends have enabled mobile users to rely increasingly on wireless devices to receive and stream video applications in their daily lives. These multihomed devices are capable of changing point of connection while roaming in current heterogeneous wireless networks, due to their multi-access radio interfaces. However, services handover between two wireless cells of same radio access technology...
Energy detection is widely used by cognitive radios for spectrum sensing. During a silent period, secondary users (SUs) are kept silent so that the energy detector does not confuse SU signals for primary user (PU) signals. Due to imperfect coordination, an SU may transmit during a silent period and cause possible false alarms. We propose to leverage matched filters that already exist in many SUs to...
Exploiting the increasing ubiquitous deployment of sensor networks, the paper presents a system called WiBee that utilizes ZigBee sensors to build real-time WiFi radio maps. The design of WiBee is motivated by the observation that a ZigBee radio can sense WiFi frame transmissions although it cannot decode WiFi frames. A sensor passively listens on the wireless channel and estimates the RSS of a WiFi...
The WiFi radio in smartphones consumes a significant portion of energy when active. To reduce the energy consumption, the Power Saving Mode was standardized in IEEE 802.11 and two major implementations, Static PSM and Dynamic PSM, have been widely used in mobile devices. Unfortunately, both PSMs have inherent drawbacks: Static PSM is energy efficient but imposes considerable extra delays on data transfers;...
With the wireless landscape being rather heterogeneous, handover between different network technologies, so-called vertical handover, becomes key to a continued success for wireless Internet access. Recently, an extension to the Stream Control Transmission Protocol (SCTP) -- the Dynamic Address Reconfiguration (DAR) extension -- was standardized by the IETF. This extension enables the use of SCTP...
The current wireless network landscape comprises a plethora of technologies including WLAN, WiMAX and 3G, and not much speaks for a radical change of the state of affairs in the near future. In light of this, it becomes pivotal to facilitate vertical handover between different types of wireless networks. Although, a large number of vertical handover schemes have been proposed in the past several years,...
Handover efficiency in wireless and mobile communication networks is an important factor in providing QoS guarantees for real time applications. The 802.11 standard requires a Mobile Node (MN) to scan all the possible channels (11 in the US) to discover available Access Points (AP's) during a handover. In a given 802.11 cell several channels are expected to be empty. Due to a full scan the MN ends...
The evolutionary programming mixed bias scheduling has been shown to provide significantly reduced end-to-end delay while maintaining comparable packet delivery ratio when evaluated using simulation experiments compared to the current IEEE 802.11 DCF standard. In this paper, proposed is an enhanced MB-EP algorithm which includes a new quiescent state called MB-EP-Q. This new approach is evaluated...
Station association information, such as an associated mesh router is required to support communication between legacy stations in Wireless Mesh Networks (WMN). Current IEEE 802.11s draft standard specifies two mechanisms to maintain the station association information: Proxy Registration Procedure (PRP) and Association Discovery Protocol (ADP). Each of them has structural limitations in that mesh...
In this paper a new backoff algorithm is proposed to enhance both the delay and the throughput performance of IEEE 802.11b MAC protocol. The proposed waiting time based backoff algorithm (WBA), observes the Waiting-time of each station during the backoff procedure in order to estimate the size of contention window in the network. The main objective of our investigation is to examine the performance...
A VCO used in a PLL inside a wireless transceiver can be sensitive to interference from other radio circuitry (e.g. on-chip PA), components of the SoC system (e.g. clocks and their harmonics) and nearby radios. To prevent VCO pulling by the PA, fractional dividers can be used to offset the VCO frequency (fVCO) with respect to the PA. Multistandard radios covering, for example, WiFi 2.4 to 2.5GHz and...
IEEE 802.11 wireless LANs can provide easy deployment and configuration for broadband wireless data services without dealing with a cable. However, when MSs roam in IEEE 802.11 wireless networks, the conventional handoff process is not suitable for seamless mobile services. In this paper, we propose a channel-switched AP architecture in which the neighboring APs cooperate in changing the RF channel...
Domestic photovoltaic (PV) based microgrid refers to a distributed group of small solar PV systems installed at each household in a residential area. The distributed systems may be integrated to form a meshed microgrid structure which can operate in both islanded and grid-connected modes. Grid-connected microgrids of domestic solar PV systems can supplement energy needs of homeowners. They are a potentially...
Wireless local area networks (WLANs) are in a period of great expansion and there is a strong need for them to support multimedia applications. With the increasing demand and penetration of wireless services, users of wireless networks now expect Quality of Service (QoS) and performance comparable to what is available from fixed networks. Providing QoS requirements like good throughput and minimum...
Two proposals are presented in this study in an attempt to solve the problem of network selection, which are based on fuzzy logic techniques and methods of decision making. The first proposal uses a combination of the fuzzy method with two MADM (Multiple Attribute Decision Making) methods, the AHP (Analytic Hierarchy Process) and the GRA (Grey Relational Analysis), whereas the latter uses only the...
Performance degradation of an IEEE 802.11g network is studied in case legacy stations are associated with the AP. Custom event-driven simulator was developed for the purpose. We demonstrate its consistency by comparing the outputs with a widely accepted network simulator and with results of an analytical study. Performance degradation is analyzed in terms of access delay and throughput. We study the...
In this paper, we explore a novel online packet scheduling model based on vehicular network applications. The model incorporates multiple networks with non-persistent connectivity where we only know which networks are available at the current time. Our goal is to achieve the minimum requirement of vehicular application classes and also maximize the throughput of these classes. NS3 simulations were...
A multi-access radio network that efficiently utilizes radio resources is a promising approach to flexible, reliable, high-capacity communication. Regarding cooperative controlling functionality in a heterogeneous radio network, two schemes are considered to be applicable to the efficient usage of multi-radio systems: link selection and link aggregation. This paper focuses on link selection and its...
Generally, IEEE 802.11 DCF is used as a MAC layer protocol to form an ad hoc network as it enables one to configure a mobile host either in ad hoc mode or infrastructure mode. In this paper, we carry out an analysis of IEEE 802.11 DCF for an ad hoc network under saturation conditions. We focus on the average end-to-end delay, throughput, and the loss probability for single hop as well as multiple...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.