Selected Methods of Measuring the Delay in Data Transmission Systems with Wireless Network Interfaces

Abstract

The article presents the concept of creating model of delays occurring in telecommunication system taking into account all sources of delays generated during data transmission between the source and destination nodes. Proposed model takes into account the existence of intermediary network devices that play a significant role in the general delay budget. The paper presents two measurement systems used to measure delays in 802.11 g based wireless networks and ones using ZigBee standard. Both systems were built based on the authors' concepts of hardware and software allowing measurement of delays by using additional connection for the synchronization of internal clocks. Described measurement systems selected amount of experiments was performed for varied network structures.

The Dedicated Wireless Communication Device for Group of Unmanned Vehicles

“…Therefore by using the presented device it is possible to implement cooperation schemes in vehicles in the same group. The device was designed on basis of previous tests [1], [8] and already tested using a group of unmanned aerial vehicles. Acquired results prove the possibility of a secure communication in a range depending of the used antenna but starting from 2 km.…”

“…It allows autonomous communication between the miniature unmanned vehicles in a group without the need for continuous ground control. The implementation is based on the results of the previous work in the field of wireless transmissions [1] and consists of two layers: the physical layer and secure communication layer. The main contribution of the article is presentation of the secure, miniature communication device that allows creation of groups of miniature autonomous unmanned vehicles.…”

Probabilistic Modeling of Delays in Data Transmission Systems with Wireless Network Interfaces Employing Random Strings Function

“…where x(t) acts as a lter and h(t) is a known input signal. Using the orthogonally condition (when h → x) [7]:…”

Analysis of EGNOS-Augmented GPS Receiver Positioning Accuracy

“…PPS receivers are additionally provided with P signal on frequency L2 = 1227.60 MHz, which makes it possible to calculate a correction and neutralize the main cause of the measurement error resulting from the distortion of radio signals in ionosphere [7,8].…”