Architectures for Mobile Rf Convergence and Future Rf Transparency Partitioning Is Key Cellular Phone 2 G, 2.5 G Multi-band User Interfaces

T latest GSM phones are already quadband, giving users extended coverage on 800 MHz, 900 MHz, 1800 MHz and 1900 MHz GSM bands across five different continents. Many also incorporate Bluetooth wireless technology for headset and SIM card synchronization functions. They will soon acquire Wi-Fi connections to take advantage of voice-over-IP (VoIP) connections, and receive digital terrestrial television, digital audio broadcasts and GPS satellite information. After that, it will be ultrawideband (UWB) for wireless USB and Wi-Max for mobile Internet access. And, it won’t only be mobile phones that sport these multiband, multimode wireless capabilities. Convergence will mean that other combinations appear in PDAs, laptop computers and game consoles. Typical mobile devices may, therefore, need to receive wireless transmissions over a total bandwidth of nearly 6 GHz (Figure 1). The current technique of devoting a separate transceiver with its own RF and baseband circuitry to each communication pipe works well provided the number of communication pipes is small. The increased integration density that has been made possible by 90 nm CMOS, new passive component integration techniques and RF system-in-package (SiP) technology has reduced the size and power consumption of these transceivers to the point where two or three can be accommodated inside lightweight handheld portables. However, as the number of wireless communication pipes increases, it will no