0000000000049538
AUTHOR
Miguel Garcia
Subjective Evaluation of Video on Demand Systems Using Different Network Connections
Nowadays, society makes use of new technologies as they appear. Due to this boom, the use of resources via web is increasing notably. In of training and education cases, companies such as universities are offering tele-learning platforms to complement and facilitate the learning process. Some of these called e-learning platforms can have explanatory videos as a resource for training. For the codification of these videos, we have to use parameters which provide a trade-off between the video sizes to be transmitted that optimize bandwidth and video and audio quality. This paper presents a subjective study of the video quality on transmission depending on the types of users’ network access to …
A Secure Spontaneous Ad-Hoc Network to Share Internet Access
In this paper, we propose a secure spontaneous ad-hoc network to grant the access of the users to surf the Web. The paper shows the description of our proposal, the procedure of the nodes involved in the system and the designed messages. We also validate the success of our proposal through several simulations and comparisons with a regular architecture. The proposal has been developed with the main objective of improving the communication and integration between different study centers of low resource communities.
A Group-Based Architecture for Wireless Sensor Networks
Many routing protocols for ad-hoc networks and sensor networks have been designed, but none of them are based on groups. We propose to divide the network into several groups of sensors. When a sensor send data to other groups, the data has to arrive just to one sensor from each group, then they propagate it to the rest of sensors in their groups. We have simulated our proposal for different types of sensor topologies to know which type of topology is the best depending on the number of sensors in the whole network or depending on the number of interior sensors. We have also simulated how much time is needed to propagate information between groups. The application areas for our proposal coul…
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…
A Group-Based Protocol for Large Wireless AD-HOC and Sensor Networks
Many routing protocols for ad-hoc networks and sensor networks have been designed, but none of them is based on groups. It is known that grouping nodes gives better performance to the group and to the whole system, thereby avoiding unnecessary message forwarding and additional overheads. We propose an approach where the network is split into several groups of sensors where connections between groups are established as a function of the proximity and the neighbor's available capacity (based on the sensor's energy). In this paper the network architecture is described with its mathematical description and the messages that are needed to proper operation. It is also simulated how much time is n…
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…
A group-based wireless body sensors network using energy harvesting for soccer team monitoring
[EN] In team-based sports, it is difficult to monitor physical state of each athlete during the match. Wearable body sensors with wireless connections allow having low-power and low-size devices, that may use energy harvesting, but with low radio coverage area but the main issue comes from the mobility. This paper presents a wireless body sensors network for soccer team players' monitoring. Each player has a body sensor network that use energy harvesting and each player will be a node in the wireless sensor network. This proposal is based on the zone mobility of the players and their dynamism. It allows knowing the physical state of each player during the whole match. Having fast updates an…
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 …