Large signal and small signal building blocks for cellular infrastructure

Mobile wireless communications have become a mainstream technology for everybody; the number of subscribers is expected to hit five billion subscriptions in 2011. Network operators have experienced a strong increase in demand for fast mobile broadband applications, which are also the focus of more recent releases for cellular communications standards as frequency spectrum for cellular applications is limited. The desired high data rates come at a price: Ever more complex modulation schemes and fairly high signal-to-noise ratios in increasingly smaller cells are required to support high speed operation. Spatial diversity multiple input multiple output (MIMO) schemes using several antennas per radio channel will become the norm in cellular infrastructures (i.e., base station designs, which aim at offering the maximum throughput to the mobile user). Network operators are faced with an increasing need for flexible solutions; installation costs and operating expenses need 170to come down as well in order to be able to deal with the increase in number of cell sites needed to offer adequate coverage and capacity in a given area. This requirement calls for highly integrated solutions to address cost; radio frequency (RF) power amplifiers with a high DC power efficiency along with new base station partitioning options such as remote radio head units significantly reduce the operating expenses.