Mobile broadband is an internet connectivity service which operates on cellular networks. With mobile broadband you can be connected anywhere with cellphone coverage.
Mobile broadband internet is often referred to as 3G. in fact, 3G is only one type of mobile broadband connectivity. There are a number of types of connectivity available, referred to as connectivity protocols or standards. The type of connectivity available varies from area to area. The most common types, from slowest to fastest, are:

GPRS EDGE UMTS including HSDPA and HSPA+ LTE LTE Advanced