Electronic Design

Software-Defined Transceiver Chip Handles Any Band And Protocol

Imagine handsets that can work on any network, in any country, and on any frequency with the prevailing protocol and with seamless handoffs. Such devices do exist, but they aren’t cheap. The implementation of multimode and multiband wireless devices requires multiple transceivers, increasing cost as well as power consumption and size—specs that commodities like cell phones can’t afford.

Software-defined radio (SDR) offers a potential solution, but it also is expensive and power-hungry. BitWave Semiconductor solves these problems with its patent-pending SDR design in its BW1102 Softransceiver RFIC. This fully configurable CMOS RF transceiver can operate from 700 MHz to 3.8 GHz. It can be programmed to handle virtually any wireless protocol, including but not limited to GSM, GPRS, EDGE, WCDMA, HSDPA, cdma2000, 1xRTT, EV-DO, 802.11b/g Wi-Fi, and 802.16d/e WiMAX.

Furthermore, the BW1102 can handle Bluetooth, DVB-H, DVB-T, MediaFLO, ISDB-T, DMB, GPS, iDEN, DECT, and any number of other special military or public safety protocols. It’s ready to take on the 4G Long Term Evolution (LTE) protocol as it comes into play later next year and beyond as well. The bandwidth is fully programmable from 25 kHz to 20 MHz.

Software mode files that define the receiver (RX) and transmitter (TX) configurations are stored in an external flash memory and loaded on power-up (see the figure). The transceiver can be reconfigured on the fly, in typically less than 125 µs. Made with 130-nm CMOS, it’s partitioned into RF, analog, mixed-signal, and digital domains. The internal domains communicate with serial peripheral interfaces (SPIs).

The device works with existing front-end modules containing filters and duplexers, matching circuits, and a power amplifier. The receiver low-noise amplifier (LNA) is on chip, in addition to the RX and TX switching. The chip interfaces to an external baseband processor and flash memory via the DigRF version 3.09 low-voltage differential signaling (LVDS) interface and BitWave’s own 12- by 12-bit parallel interface.

Handset OEMs and carriers as well as end consumers all will see some excellent benefits. For example, designers can use one chip to achieve any frequency/protocol combination in mid-range to high-end multimode phones, lowering costs and reducing timeto- market. It also reduces the printed-circuit board (PCB) area, power consumption, and the total number of discrete components.

The Softransceiver can be configured to function across and between networks and add new modes after the sale of the device. Consumers will see super-thin phones that will operate worldwide. They also will be able to customize these phones for desired services and update them later in the field without having to buy a new phone each time services or technologies change. And, the need for two phones virtually goes away.

The BitWave BW1102 targets smart phones and feature phones as well as femtocell and other home-access points. It comes in a standard 7- by 7-mm 144-ball plastic ball-grid array (PBGA) package. It operates from standard battery voltages. And, it uses one standard crystal. Samples will be available in August. Full production is expected later in the fourth quarter of 2008. Look for future versions with multiple receivers and transmitters on a chip that will further enable cost-effective and power-sensible multimode multiband devices and multiple-input/multiple-output (MIMO).


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