he dealer. As automobiles include more computer-driven functions-particularly electric vehicles-software updates and software maintenance will become more critical and sophisticated. All M2M transactions require software applications that synchronize the transac- tion with the device, schedule the transaction, and perform authentication and security functions. Using Prepaid Mobile Services Prepaid wireless services are those for which customers pay in advance for mobile voice and/or data services. Prepaid service is most widely offered to customers who do not have credit and who pay cash for service. They "top off" their service, making additional payments when they need more minutes. This contrasts with the postpaid cellular model by which customers are billed for and pay for services after the end of the monthly billing period. In the United States, MetroPC offers only prepaid service. Customers give MetroPCS a credit card number that MetroPCS bills every month. It offers no postpaid services. Other mobile providers in the United States rely on post- paid customers for the bulk of their revenue, but many offer prepaid as a way to round out their offerings. Worldwide, prepaid users outnumber those with postpaid plans. With postpaid plans, customers receive monthly bills and often sign one- or two-year contracts for their service. According to UK-based research firm Ovum, prepaid connections made up 75 percent of the total worldwide user base in 2010. This statistic was published by Rethink-Wireless in a January 12, 2011 article by Caroline Gabriel titled "Shift to Prepaid Will Need New Back Office Systems." Wi-Fi Standards, Architecture, and Use in Cellular Networks The consumption of prepaid service is particularly high in developing countries. For instance, at MTN Nigeria, more than 90 percent of its subscriber base uses mobile prepaid for their service. Similar patterns apply to India, Bangladesh, and many Afri- can countries. Average monthly payments in rural areas of India and Bangladesh are $2-$3. Prepaid 