MB-OFDM based UWB Transceiver Chip
Fri, 05/28/2004 - 6:30am
UB501 developer kit
The 115 member MBOA membership is moving forward to complete the development of the UWB PHY specification.
While the IEEE 802.15.3a committee continues its struggle in selecting the ultra-wideband- (UWB)-based wireless personal area networks (WPAN) standard, the multiband orthogonal frequency-division multiplexing (OFDM) Alliance (MBOA) has solidified its presence by its ongoing efforts toward completion of its PHY standard (v1.0 scheduled for late May 2004 release) and more importantly achieving the support of the industry. The MBOA membership now exceeding 115 includes the top consumer electronics, personal computer, mobile and portable device and semiconductor manufacturers. Wisair has been a contributing member and author, and member of its steering committee.
The MBOA is completing the development of UWB PHY specifications to meet the industry requirements for the very high speed WPAN applications. Typical UWB applications will include wireless multimedia, wireless USB and wireless 1394 applications for content streaming with quality of service and for large data transfers in the digital home and beyond. Compliant devices will deliver data rates up to 480 Mb/s with the current specifications and exceeding 1 Gb/s in the near future. UWB achieves such data rates with about 1 Mb/s for each mW consumed.
The MB-OFDM technology utilizes multiple bands in order to achieve the most optimal performance, with interference mitigation and higher multiple piconet performance. The mandatory modes include the use of the lower three bands. Each band occupies 528 MHz and contains 128 OFDM tones, each carrying 3.2M quadrature phase-shift keying (QPSK) symbols. While the constant raw bit rate is 640 Mb/s, the effective data rate may be 55, 80, 110, 160, 200, 320 or 480 Mb/s. The difference is used for coding and redundancy (by spreading or mirroring), to provide wider dynamic range thus significantly increasing the effective operating distance. While the system will reach 2 to 4 meters at 480 Mb/s, it can achieve 10 to 30 meters at the lower data rates, with today's FCC allowed transmit level.
As an attempt to strengthen the MOBA, Wisair has developed the industry's first MB-OFDM RF Transceiver chip, the Wisair UB501. The UB501 is part of Wisair's two chip UWB solution. The RF Transceiver provides all key RF PHY blocks with a direct interface to the antenna. The Wisair chipset partitioning allows manufacturers configure the chipset based on their system design needs and configuration.
The Wisair UB501 supports eight bands including the three mandatory bands, occupying 3.1 to 7.4 GHz frequency span. It is compliant with the MBOA specifications, requires minimal external passive components and no inductors. All functional blocks include their required filters on-chip. The UB501 also includes an on-chip VCO running off of an external off-the-shelf crystal.
The fast switching waveform generator is the heart of the UB501. It creates one of eight OFDM waveforms or the bands under the baseband chip control. Each band can be independently turned off and on. On the receive side the receive circuitry covers very large bandwidths 3.1 to 7.4 GHz at all times, which has been a significant RF engineering challenge, specifically to achieve linearity and low noise figure across the whole 8 bands.
The UB501 is packaged in a 56-pin package operating with a 3V power supply. Besides the regular transmit/receive operation mode, it supports stand-by and sleep modes with mW and μW level power consumption, respectively.
Wisair UB501 is available with Wisair MB-OFDM Evaluation toolkit for advanced development purposes. Later this year, Wisair will provide Development Kits based on UB501 RF Transceiver and UB531 baseband chipsets.