Search

U okviru ovog rada obavljena je analiza podataka o kratkotrajnim ispadima baznih postaja mobilnih mreža druge i treće generacije. Kratkotrajni ispadi su karakterizirani kao ispadi baznih postaja koji pojedinačno ili zajedno ne prelaze trajanje od 30 minuta čime ne narušavaju operativnost bazne postaje od 98% u danu. Rezultati analize pokazuju povezanost doba dana i dana u tjednu u kojem je došlo do kratkotrajnog ispada na način da u udarnim satima u danu i u radnim danima u tjednu dolazi do duljih ispada, većeg broja ispada i veće količine neprenesenog prometa. Količina kratkotrajnih ispada i njihovo prosječno trajanje proporcionalni su količini procijenjenog neprenesenog prometa. Nepreneseni promet se odnosi na procjenu prometa koji bi bio prenesen kada do kratkotrajnih ispada ne bi došlo. Također, rezultati pokazuju da kratkotrajni ispadi većinski zahvaćaju sve sektore bazne postaje koja je zahvaćena ispadom. Utvrđeno je da je 50% kratkotrajnih ispada u 2G mreži i 30% kratkotrajnih ispada u 3G mreži dulje od 5 minuta. Također, utvrđeno je da se u jednom 15 minutnom vremenskom intervalu za 90% slučajeva dogodi ispad do 10 pojedinačnih sektora i do 3 cjelokupne bazne postaje. Rezimiranjem dobivenih rezultata donesen je zaključak da kratkotrajni ispadi značajno narušavaju operativnost mobilnih mreža druge i treće generacije, uzrokuju korisničko nezadovoljstvo uslijed uskraćivanja usluge te uzrokuju novčane gubitke operateru. ABSTRACT: An analysis on short time cell outages (STCO) is performed on data gathered from 2G and 3G cellular networks. A short time cell outage is defined as an outage affecting all or some cells in a base station that lasts up to 30 minutes in a day and don't affect a 98% of daily operation in a cellular network. The results show an impact of the time of the day and the particular days in the week on the number and the duration of STCOs. During the peak hours in a day when the network is utilized at its most , more STCOs occur and they last longer in comparison with the night hours and the weekends when the network is less utilized. An analysis on the transferred traffic and the estimated non transferred traffic is performed. Results show that higher rates of non transferred traffic come with a higher number of STCOs and longer STCO duration. Additionally, it is shown that most STCOs occur on whole base stations as opposed to single sectors. Results show that 50% of 2G STCOs and 30% of 3G STCOs last longer than 5 minutes. Further analysis on the number of affected sectors during each 15 minute interval shows that in 90% of cases there are up to 10 sectors affected by STCOs and up to 3 whole base stations. Having the given results in mind, it is concluded that STCOs affect the overall operation of the network, are far from negligible as they affect the user satisfaction and the QoS for the operators. Also, STCOs cause a direct revenue loss to the operator.