Current Access Point Research Articles

A Machine-Learning-Based Access Point Selection Strategy for Automated Guided Vehicles in Smart Factories.

Automated Guided Vehicles (AGVs) are becoming popular at many manufacturing facilities. To ensure mobility and flexibility, AGVs are often controlled by wireless communication, eliminating the constraints of physical cables. These AGVs require multiple Access Points (APs) to ensure uninterrupted coverage across the site. As AGVs move, they need to switch between these APs seamlessly. A primary challenge is that the communication downtime during this link-switching process must be minimal for effective AGV monitoring and control. Current AP selection strategies based on observed Received Signal Strength Indicator (RSSI) often fail in manufacturing environments due to RSSI's inherent instability. This paper introduces a new AP selection technique for AGVs navigating these sites. Our approach harnesses the distinct movement patterns of AGVs and uses machine learning techniques to learn location-, trajectory-, and orientation-specific RSSI from the APs. Real-world factory data from our unique dataset revealed that our method extends the potential communication duration per route by 1.34 times compared to the prevalent signal strength-based switching methods commonly implemented in current drivers provided by chipset vendors or open-source Wi-Fi drivers. These results indicate that the automatic evaluation and tuning of the wireless environment using the proposed method is beneficial in reducing the time and effort required to investigate the detailed propagation paths needed to adapt AGV to existing APs.

AP Association Algorithm Based on VR User Behavior Awareness

With the rapid development of virtual reality (VR) technology, this paper proposes an access point (AP) correlation method based on VR user behavior awareness to address the problem of how current AP correlation methods only focus on the performance improvements of ordinary users and ignore the impact of VR user behavior on service quality. This paper analyzes the AP association method under the coverage scenario of a multi-access point (multi-AP) scenario environment and controls the performance improvement of VR user APs or APs under the access controller (AC) by association. Firstly, the VR network application scenario and system model were constructed, and secondly, the user behavior was sensed by analyzing the viewing habits of users. Then, the VR user association problem based on VR user behavior perception was transformed into a “many-to-many” matching problem between VR user devices and APs, and the generalized multidimensional multiple choice knapsack (GMMKP) model was established to solve the problem using the backpack problem theory; the suboptimal solution algorithm was selected to obtain the best VR user AP association strategy. The experimental results show by simulation that the proposed algorithm in this paper performed better in terms of the AP load balancing and average network download latency compared to the comparison algorithms.

ProStream: Programmable Underwater IoT Network for Multimedia Streaming

Underwater Internet of Things (IoT) faces challenges, such as low data rate, high node mobility, high error probability, and propagation delay. Furthermore, underwater multimedia communication is more challenging, as it requires a high data rate and reliable delivery. The next-generation networking paradigm—software-defined network (SDN)—improves flexibility and virtualization through programmability. SDN increases resource utilization, simplifies management, and reduces operating costs. This article proposes ProStream, a reconfigurable SDN-based underwater multihop network for improved topology management, association control, and multimedia transmission. The proposed scheme considers a network with multiple access points (APs) and mobile relays and stations. The SDN controller places flow rules in the relays, and APs are placed as per the location of the nodes. Moreover, we present a programmable station for reducing Tx/Rx complexity in underwater networks. The stations or relays are triggered through programmability to notify their sleep time and current relays and AP for association and data transmission. We evaluate the proposed scheme first through simulation-based experimentation. We also develop a small-scale real testbed prototype of the proposed SDN. The performance results show significant improvement of performance in terms of latency, throughput, and packet delivery ratio.

HST Communication Network by Integration of Software-Defined Networking and Network Function Virtualization

Abstract: The new challenges introduced in the wireless communication systems by the rapid developments of high-speed trains (HSTs) and more usage of the smartphones. The smart transportation involves the large crowd with smart phones, that requires a more efficient network for communication without disconnection. To achieve that, the handover process, need to be done quickly with respect to the speed of the train. To sustain its session connectivity to the internet, it requires the disconnection from the current access point (APc) to the next access point (APn). IN this project, we use the open flow and open stack protocols for integrating the interface between the infrastructure and the controller. Along with this, the integration of software-defined networking and network function virtualization is also done. The project majorly concentrated on the modification of the routes of the packet flow from one access point to the next required access point with the use of the triggering signal from the train which gives the location of the train. The suggested method works by the transmitting the signal from train to the next access point in advance so that the SDN controller changes the path of the packets to the next access point. The parameters like Signal strength, packet loss, average delay, path delay is evaluated. Along with these parameters the energy dissipation near the network also evaluated. The experimental results are evaluated using MATLAB tool. Keywords: Network Function Virtualization, OpenFlow in SDN, OpenStack, Software Defined Network.

Wireless Optimization Algorithm for Multi-floor AP deployment using binary particle swarm optimization (BPSO)

Optimizing the Access Point (AP) deployment is of great importance in wireless applications owing the requirement to provide efficient and cost-effective communication. Highly targeted by many researchers and academic industries, Quality of Service (QOS) is an important primary parameter and objective in mind along with AP placement and overall publishing cost. This study proposes and investigates a multi-level optimization algorithm based on Binary Particle Swarm Optimization (BPSO). It aims to an optimal multi-floor AP placement with effective coverage that makes it more capable of supporting QOS and cost effectiveness. Five pairs (coverage, AP placement) of weights, signal thresholds, and Received Signal Strength (RSS) measurements simulated with Wireless Insite (WI) software were considered to work in conjunction with the proposed optimization algorithm. Additionally, the AP deployment results obtained from WI and optimization will be compared with the simulation results of the current AP diffusion within the target building. These comparisons will be based on the most important RSS parameters, path loss (PL) and interference. The comparison results showed a significant improvement in RSS and path loss values of (-11.55) dBm and (11.55) dBm. While the interferences are decreased by (7.87 %). Furthermore, the result of performance analysis showed that the proposed algorithm outperforms the current AP deployment by 39.23% in coverage ratio.

Fixing Target Access Point with low load during Handoff in WLAN

It is obvious that providing continuous service for a Mobile Node (MN) which is in frequent movement is a major challenge nowadays. Finding and fixing the best neighboring Access Point (AP) for Mobile Node which is in movement is a tedious task. In the existing system time period of Mobile Nodes waiting for all neighboring APs to respond is too long. AP which are busy may not be able to respond to the request. For this reason, novel idea to fix target access point during handoff in WLAN is proposed. A Neighboring Graph Model (NGM) is used which is built to store and retrieve the neighbors of the current AP. The lists of neighboring APs are provided by the NG and target AP is selected based on the low load. The simulation results showed that the proposed handoff considerably decreases the time to fix the target Access Point.

A user application-based access point selection algorithm for dense WLANs.

The current commercial access point (AP) selection schemes are mostly based on received signal strength, but perform poorly in many situations. To address this problem, a number of alternative schemes collect and analyze the actual load of every candidate AP. However, these schemes may incur significant latency and signaling overhead in dense wireless local area networks (WLANs). To mitigate such overhead, we propose a user application-based AP selection scheme that considers historical information about AP performance. Without inducing any signaling activity, our scheme monitors the amount of network traffic used by applications and estimates the achievable throughput of APs. Our scheme employs the characteristics of application traffic with the intent of accurately predicting AP performance. Using a measurement study in dense WLAN environments, we show that our scheme achieves higher throughput and lower association latency than those of existing schemes in places highly accessible to the user.

Are reference pop-up widgets welcome or annoying? A usability study

Purpose The purpose of this study is to investigate user reaction to pop-up chat widgets for possible use as a promoter of online reference services in libraries. Design/methodology/approach Librarians at three different campuses of the Pennsylvania State University interviewed ten students at each campus. Librarians used a script to ask students to respond to various library websites and the potential utility of a pop-up widget. Students also responded to a sample chat widget and were asked to evaluate the timing of its appearance on the page. Findings All participants indicated on a timeline their preferred time for a pop-up to appear on a web page. Only 16 per cent of study participants had used the “Ask a Librarian” reference service from its current access point as a linked button on the libraries’ web pages. However, 83 per cent indicated that they would be more likely to use the Ask service if the widget appeared on the screen. Originality/value This research is unique, as there are no other studies in the library literature that explore pop-up chat widgets.

A novel software‐defined networking approach for vertical handoff in heterogeneous wireless networks

AbstractWe propose a novel vertical handoff scheme with the support of the software‐defined networking technique for heterogeneous wireless networks. The proposed scheme solves two important issues in vertical handoff: network selection and handoff timing. In this paper, the network selection is formulated as a 0‐1 integer programming problem, which maximizes the sum of channel capacities that handoff users can obtain from their new access points. After the network selection process is finished, a user will wait for a time period. Only if the new access point is consistently more appropriate than the current access point during this time period, will the user transfer its inter‐network connection to the new access point. Our proposed scheme ensures that a user will transfer to the most appropriate access point at the most appropriate time. Comprehensive simulation has been conducted. It is shown that the proposed scheme reduces the number of vertical handoffs, maximizes the total throughput, and user served ratio significantly. Copyright © 2016 John Wiley & Sons, Ltd.

Ticket-Based Authentication for Fast Handover in Wireless Mesh Networks

Wireless mesh networks have grown very rapidly in recent years, owing to the features of self-organization, low installation costs, large-scale deployment, and fault-tolerance. Fast and efficient authentication schemes are especially important in multi-hop WMNs. We propose two novel ticket-based mutual authentication protocols in order to minimize the latency, one for initial authentication and the other for fast handover. The 4-way handshake in the phase of login authentication is cut down to 2-way using the Login-Ticket. The authentication server does not need to be involved in the handover authentication process. Instead, the target mesh access points authenticate mobile clients using the tickets pre-distributed by the current access points, avoiding multi-hop wireless communications between the authentication server and the mesh clients/points. Furthermore, even if the client has to handover several times, the AS is still not required to be involved in the process. Security analysis shows that our proposed protocols are secure and resilient to various kinds of attacks. Performance analysis demonstrates that the protocols are efficient in terms of authentication delay and communications costs, thus they are very suitable for circumstance of WMNs.

A DEVELOPED NETWORK LAYER HANDOVER BASED WIRELESS NETWORKS

This paper proposes an Advanced Mobility Handover (AMH) scheme based on Wireless Local Area Networks (WLANs) by developing a network layer handover procedure which triggers messages to be sent to the next access point. The proposed AMH scheme performs the network handover process, which is represented by binding update procedure in advance during the time mobile node is still connected to the current AP in the link layer. Furthermore, a unique home IPv6 address is developed to maintain an IP communication with other corresponding nodes without a care-ofaddress during mobile node$'$s roaming process. This can contribute significantly to reducing network layer handover delays and signaling costs by eliminate the process of obtaining a new care-of-address and processing the handover of network layer in advance while the mobile node is still communicating with the current access point. Eventually, the conducted OMNET++ simulated scenario shows that the proposed AMH scheme performs the best in terms of reducing the handover delay as compared to the state of the art.

Advanced mobility handover for mobile IPv6 based wireless networks.

We propose an Advanced Mobility Handover scheme (AMH) in this paper for seamless mobility in MIPv6-based wireless networks. In the proposed scheme, the mobile node utilizes a unique home IPv6 address developed to maintain communication with other corresponding nodes without a care-of-address during the roaming process. The IPv6 address for each MN during the first round of AMH process is uniquely identified by HA using the developed MN-ID field as a global permanent, which is identifying uniquely the IPv6 address of MN. Moreover, a temporary MN-ID is generated by access point each time an MN is associated with a particular AP and temporarily saved in a developed table inside the AP. When employing the AMH scheme, the handover process in the network layer is performed prior to its default time. That is, the mobility handover process in the network layer is tackled by a trigger developed AMH message to the next access point. Thus, a mobile node keeps communicating with the current access point while the network layer handover is executed by the next access point. The mathematical analyses and simulation results show that the proposed scheme performs better as compared with the existing approaches.

Minimization of Call Blocking Probability using Mobile Node velocity

Due to rapid growth in IEEE 802.11 based Wireless Local Area Networks (WLAN), handoff has become a burning issue. A mobile Node (MN) requires handoff when it travels out of the coverage area of its current access point (AP) and tries to associate with another AP. But handoff delays provide a serious barrier for such services to be made available to mobile platforms. Throughout the last few years there has been plenty of research aimed towards reducing the handoff delay incurred in the various levels of wireless communication.In this article, we propose a received signal strength measurement based handoff technique to improve handoff probability. By calculating the speed of MN (Mobile Node) and signaling delay information we try to take the right decision of handoff initiation time. Our theoretical analysis and simulation results show that by taking the proper decision for handoff we can effectively reduce false handoff initiation probability and unnecessary traffic load causing packet loss and call blocking.

Security of Handoff Latency by Prescanning with help of Neighbourgraph

Due to rapid growth in IEEE 802.11 based Wireless Local Area Networks (WLAN), handoff has become a burning issue. A mobile station (MS) requires handoff when it travels out of the coverage area of its current access point (AP) and tries to associate with another AP. But handoff delays provide a serious barrier for such services to be made available to mobile platforms. Throughout the last few years there has been plenty of research aimed towards reducing the handoff delay incurred in the various levels of wireless communication. In this paper, based on Neighbor Graph Cache (NGC), we introduce a prescanning mechanism in which an STA starts scanning before it needs actual handoff. The simulation results show that the proposed method reduces the handoff latency effectively.

Improved Handoff Efficiency with the help of Neighbour Graph using Carrier to Interference Ratio

Presently, IEEE 802.11 based wireless local area networks (WLAN) have been widely deployed for business and personal applications. The main issue regarding wireless network technology is handoff or hand over management. When a mobile station (MS) moves outside the range of its current access point (AP) it needs to perform a link layer handover. This causes data loss and interruption in communication. According to IEEE 802.11, link layer2 (L2) handoff is performed in three phases – scanning, authentication and re-association. Scanning process causes 90% of the total handoff delay. Throughout the last few years, plenty of researches had been done to reduce the hand off delay by reducing the scanning delay. In this paper, we propose to reduce handoff latency for IEEE 802.11 wireless networks with Neighbor Graphs (NG) pre-scanning mechanisms. IEEE 802.11 uses 11 channels of which the channels 1, 6 and 11 do not mutually overlap. So these channels are expected to have a lower carrier-to-interference ratio (CI) compared to other channels under the same base station, which increases the channel‟s availability during handoff. Based on the NG prescanning mechanism, when handoff criterions have been met, we design an algorithm to first scan the channels 1, 6 and 11, if present under the next Access Point (AP), to reduce the scanning delay. We also introduce pre-authentication mechanism, which will effectively reduce the message processing delay.

Improvement of Handoff Latency by GPS based Handoff Technique

Presently IEEE 802.11b based wireless networks are being widely used in various fields like personal as well as business applications. Handoff is a critical issue in IEEE 802.11b based wireless networks. When a mobile node (MN) moves away from the range of its current access point (AP) it needs to perform a link layer handoff. This causes data loss and interruption in communication. According to IEEE 802.11b link layer2 (L2) handoff consists of three phases - scanning, authentication and re,association. Scanning process delay is 90% of the total handoff delay. So in this paper we propose a better scanning mechanism to reduce handoff latency. Using GPS we determine the direction of velocity of the MN as well as position. It reduces the time to find the closest and best AP among all neighbor APs. This process effectively reduces the handoff latency.

GroupScan: Group-Based Fast Handoff Scheme for Wireless LAN

Handoff is a critical issue for stations in IEEE 802.11-based wireless networks. In order to provide Voice-over IP (VoIP) and real-time streaming applications to stations, a handoff mechanism is needed that can reduce latency and provide seamless communication. However, the IEEE802.11 handoff scheme is not appropriate to supply their quality of service (QoS), because it is based on a full-scanning approach. Full-scanning spends too much time searching for access points (APs). Therefore, various pre-scan handoff protocols such as SyncScan and DeuceScan have been proposed. They scan to find nearby APs before the station loses contact with its current AP, but the pre-scanning overhead is considerable. Our handoff mechanism reduces the delay and overhead associated with the link layer handoff by periodically scanning the channel groups.

Design and evaluation of a novel MAC layer handoff protocol for IEEE 802.11 wireless networks

In recent years, the IEEE 802.11 wireless network family has become one of the most important set of standards in the wireless communications industry. IEEE 802.11 compliant devices are inexpensive and easier to configure and deploy than other wireless technologies. In an IEEE 802.11 wireless network, wireless terminals can move freely. As a result, when the wireless terminal moves away from its current access point, it must switch to another access point to maintain the active connection. This is known as the MAC layer handoff process. MAC layer handoff latency should be minimized to support real-time applications and to provide mobile devices with seamless roaming in IEEE 802.11 wireless networks. This paper proposes a novel MAC layer handoff protocol over IEEE 802.11 wireless networks by introducing advertisement messages sent from other mobile nodes and from which wireless terminals are able to receive the information of access points in their neighborhood. A mobile node can try to associate with access points based on the prediction before starting the probe process. The experimental results demonstrate that our solution can reduce MAC layer handoff latency to meet the requirements of real-time applications.

Optimizing Access Point Allocation Using Genetic Algorithmic Approach for Smart Home Environments

In recent years, high-bandwidth and low-cost wireless technologies have emerged as a competitive element, enabling the smart home environment. On the other hand, with the increasing demands for various services, the current access point allocation schemes give rise to significant challenges for a stable connection service, bandwidth and load distribution. In this paper, we present an optimal access point allocation scheme based on genetic algorithm that attempts to optimize multiple parameters, such as bandwidth, and load-balancing requirements. The proposed allocation scheme provides a set of approximately efficient solutions, which allows a wireless user to choose an access point based on its capacity and load balancing, not only regarding its signaling strength or service set identifier. The simulation results are provided to demonstrate the impact of the proposed optimization procedure on overall system performance in terms of connection distribution, load balancing and call dropping probability.

DSMeM Streaming: distributed system to mitigate the effects of performance anomaly and user mobility on IEEE 802.11 WLANs

On IEEE 802.11 wireless LANs (WLAN) the clients have control over the handoff procedure; a client decides the best AP (access point) to be associated to and when and where to change its association to a new AP. This simple handoff management technique can have negative effects for both static and mobile clients of the same cell, since some wireless clients remain associated with their current AP even when a better AP is reachable. Combined with handoff latencies, this mobility method can have a negative effect on various services with severe restrictions regarding delivery rate and delay. In this paper, a distributed and transparent system that monitors channel conditions, manages user data based on its knowledge and induces client handoffs when a better AP is reachable, is presented. One of the strongest points of the proposed solution is that it can work in currently deployed IEEE 802.11 WLANs without the server, clients or APs having to introduce new software.