0000000000528138
AUTHOR
Diana Bri
A User-Balanced System for IP Telephony in WLANs
Wireless IP telephony is becoming very popular between the users of large wireless local area networks (WLANs). This increment has been mainly caused because it allows cost savings. Although, large WLANs use to provide high availability and redundancy, WLANs lack on the available throughput when there are many IP telephony users. In this paper we present a system that reallocates IP telephony devices when the system detects that an AP is overloaded. The algorithm and the frames used for our proposal are described. Measurements taken show how the bandwidth consumed is transferred from an access point to another when our proposal is running. Finally, we show the time needed to re-associate re…
A New Neighbour Selection Strategy for Group-Based Wireless Sensor Networks
In any type of networks a neighbour selection method is needed to form the topology of the network and to know which node the information has to be sent to reach a destination. Nowadays, several selection strategies exist that are based on different aspects and mainly designed to work in common networks. In this paper we will show our study about those different methods and, then we show the development of a suitable neighbour selection strategy for group-based wireless sensor networks (WSN) that is based on a capacity parameter defined by us and the new neighbour distance. We also present the proposal architecture for WSNs and the protocol when a new node joins a group and has to select it…
How the Atmospheric Variables Affect to the WLAN Datalink Layer Parameters
There are many issues that affect to WLAN connections (walls, vegetation, rain, objects in the Fresnel zone, etc.). Network designers and telecommunication practitioners must take them into account when they are planning wireless connections between devices. Some studies have demonstrated the implication of the atmospheric variables in the frequency attenuation and in the line of sight of the waves. But, to the extend of our knowledge, there is not any work published that relates the atmospheric variables with the datalink layer parameters of the WLANs. We must take into account that the datalink layer allows us to measure quite more parameters than the physical layer. After a review of the…
Using MANET Protocols in Wireless Sensor and Actor Networks
Although there are several routing protocols for wireless sensor and actor networks (WSAN), none of them have became standard. Now, there are several standard protocols for mobile ad hoc networks (MANET) that have been developed for devices with higher computing features than the sensor nodes. On the other hand, one of the main characteristics of the MANET protocols is their scalability. In this paper, we show the performance of a WSAN, when MANET protocols are used, for several topologies. We will discuss and evaluate which standard protocol is the best one depending on the number of nodes in the topology and depending on their mobility. Finally we will show their comparison. As far as we …
A Multisensor Proposal for Wireless Sensor Networks
Every sensor node in a wireless sensor network (WSN) has a microcontroller, a transmitter/receiver and a sensor. It is able to acquire data from specific point in a real environment and transmit it through the WSN. Sometimes it is useful to gather different type of data from the same place in order to obtain a final result. In the related literature, very few works are about sensing different parameters using a unique sensor. In this paper we propose a Wireless IP multisensor that is able to gather several types of data from the environment and transmit the result of their combination. Our proposal decision has being mainly based on its development costs, its expansion capacity and its flex…
Measuring the weather’s impact on MAC layer over 2.4GHz outdoor radio links
The weather s impact on the performance of a radio link at the 2.4 GHz ISM (Industry, Scientific and Medical) band had not been yet studied in great detail up to now as it is generally believed that the ultra-high frequency band is not significantly affected by weather conditions. However, our study shows significant correlations between meteorological variables and control frame errors at MAC (Medium Access Control) layer of the IEEE 802.11b/g standard. This study is performed over an outdoor radio link setting which has been monitored for several months. Moreover, we check if link distance and so modulation scheme and data rate are also decisive features of such impact. Our real scenario …