Lý thuyết mạng không dây P4

As was mentioned in the previous chapter, the era of mobile telephony began with the development and operation of the First Generation (1G) of cellular systems in the late 1970s. Although these systems have found widespread use and are still used nowadays, the evolution of technology has enabled the industry to move to Second Generation (2G) systems, the successors of 1G systems. 2G systems overcome many of the deficiencies of 1G systems mentioned in the previous chapter. Their increased capabilities stem from the fact that, contrary to 1G systems, 2G systems are completely digital. ...