Effect of WiFi systems on multimedia applications
Zoltán Gál, zgal@unideb.hu
Andrea Karsai, kandrea@fox.unideb.hu
Péter Orosz, oroszp@unideb.hu
University of Debrecen, Center of Informatics
Wireless data transmission mechanisms that belong to the IEEE 802.11 family are spreading widely in indoor and outdoor environments as well due to their mobility feature. When deploying hotspots several considerations are required to be taken about the applied technology. This is more than just an economical or rational issue it requires efficiency analysis as well. The WiFi system is based on the ISM (Industrial-Science-Medical) frequency range that allows service providers to deploy and operate multiple hotspots in the same physical area independently from each other. In outdoor environment the different service providers use radio channels practically in a rarely reconciliation way. Since ETSI standards are applied to the radiated microwave power the densely deployed systems may cause interference with each other.
In company or academic environment network users set up more and more requirements about mobile WiFi devices (such as laptops, palmtops, intelligent mobile phones) to support multimedia services. Since IP phone systems are dynamically spreading in academic environment we need to analyze the usability of WiFi phones during physical movement in indoor and outdoor environment. In the 2.4GHz ISM range the voice transmission feature of the WiFi IP phone greatly depends on the applied voice encoding mechanism. The 5GHz WiFi transmission has a special channel coding mechanism that is more effective than that of the 802.11g. Its transmission rate is very sensitive to the distance between the access point and the client. At the physical movement the high compression ratio data transmission standards are more sensitive to the radio cell roaming than the algorithms with lower compression ratio.
We know from previous analyses that the quality of multimedia services on mobile terminals is heavily affected by the velocity of the terminal during physical movement[1]. On mobile terminals the quality of multimedia applications depends strongly on data-link layer events.
In company or academic environment network users set up more and more requirements about mobile WiFi devices (such as laptops, palmtops, intelligent mobile phones) to support multimedia services. Since IP phone systems are dynamically spreading in academic environment we need to analyze the usability of WiFi phones during physical movement in indoor and outdoor environment. In the 2.4GHz ISM range the voice transmission feature of the WiFi IP phone greatly depends on the applied voice encoding mechanism. The 5GHz WiFi transmission has a special channel coding mechanism that is more effective than that of the 802.11g. Its transmission rate is very sensitive to the distance between the access point and the client. At the physical movement the high compression ratio data transmission standards are more sensitive to the radio cell roaming than the algorithms with lower compression ratio.
We know from previous analyses that the quality of multimedia services on mobile terminals is heavily affected by the velocity of the terminal during physical movement[1]. On mobile terminals the quality of multimedia applications depends strongly on data-link layer events.