Coverage analysis of Skype VoIP services over 3G cellular networks

Provision of voice services over 3G W-CDMA radio access networks is generally designed as a function of the air interface requirements of circuit-switched (CS) connections. On the other hand, packetized VoIP speech services such as Skype, which is becoming increasingly popular among 3G users, impose a more demanding set of requirements on the radio interface, carrying a penalty in terms of coverage. This work quantifies such penalty as a function of key parameters of the radio uplink. Results show that Skype coverage is always a fraction of conventional CS speech connections, and that such fraction is mainly a function of the vocoder type selected by Skype and the uplink Block Error Rate. It is found that Skype cell coverage probability ranges from 67% to 98% of the CS voice service coverage. As a result of this analysis, a set of recommendations aimed at closing the gap between CS voice and Skype coverage is formulated.