AirHook technology review
The Radiospire AirHook chipset implements a UWB point to point airlink with a transmitter on one end and a receiver on the other end. The chipset is composed of three devices on the TX end of the link and three counterpart devices on the RX end of the link (Table 4, Figure 5).
Click here for Table 4.
Table 4: Radiospire AirHook chipset..
Click here for Figure 5.
Figure 5: Radiospire wireless HDMI solutionUWB TX and RX. The video interface supports almost any standard format including HDMI, DVI, XGA and analog video such as NTSC, composite and S-video.
The AirHook chipset employs OFDM signaling with 512 carriers using 16-QAM modulation. The spectrum of the RF signal is 1.7 MHz wide, from 3.1 to 4.8 GHz. The 6-bit ADCs (Analog to Digital Converters) and DACs (Digital to Analog Converters) operate at 1.92 Gsamples/sec on an 850 MHz baseband signal.
The Radiospire Baseband processor (figure 6) incorporates Low Density Parity Check Coding (LDPC) Forward Error Correction (FEC) functionalitypowerful FEC technology that significantly reduces bit error rate. While the raw airlink data rate reaches 2.2 Gbps, the LDPC corrected data rate is 1.6 Gbps, the throughput required for 1080p HD A/V transport.
Click here for Figure 6.
Figure 6: Radiospire Baseband Processor was able to operate in either transmit or receive mode and interfacing between the video interface, such as the HDMI or the SVGA, and ADC or DAC chips.
The Radiospire ADC and DAC (Figure 7) have been segregated into their own 0.35um SiGe BiCMOS ICs for optimum performance.
Click here for Figure 7.
Figure 7: Radiospire ADC and DAC devicesInterfacing between the RF front end and the baseband processor.
The Radiospire RF receiver and transmitter (Fgures 8, 9) have also been segregated into their own 0.35μm SiGe BiCMOS ICs to optimize signal integrity and bit error rate performance.
As evident from Figures 6 through 9, the clean segregation of the AirHook architecture and focused implementation of each functional block may explain why Radiospire has been able to reach 1.6 Gbps on their UWB interface.
Click here for Figure 8.
Figure 8: Radiospire RF receiver device interfacing to the ADC.
Click here for Figure 9.
Figure 9: Radiospire RF transmitter device interfacing to the DAC.
Following our recent EE Times UWB test, we were glad to discover that the throughput performance of UWB now has a new record of 1.6 Gbpsperformance verified for the Radiospire AirHook chipset.
This is a significant step up from the 675 Mbps PHY rate of Pulse-LINK's CWave, the winner of our last test and much higher than WiMedia, which delivered around 50 Mbps at the CW-USB application layer and now promises around 160 Mbps with the next generation products.
It is notable that the two highest performing UWB chipsets available today are not based on the WiMedia standard and exceed the verified and expected WiMedia performance by an order of magnitude.
Radiospire is the first to enable uncompressed 1080p HD video transport in the UWB band at a level of throughput that seemed unreachable just a short while ago. While Radiospire's technology can be adapted to the emerging standards based 60 GHz band, the UWB solution is the only working solution on the market today.
Radiospire's robust performance at a variety of antenna orientations, in the presence of interference and through obstructions will enable solid and successful UWB based products.
Detailed information about the test methodology is available at http://www.wirelessnetdesignline.com/howto/uwb/206800514.
A PDF version of this article is available at /www.octoscope.com/Radiospire_rest_report.pdf.
About the author
Fanny Mlinarsky is the President of octoScope, a consulting firm focusing on architecture and performance of wireless data communications systems. She can be reached at firstname.lastname@example.org.