MANHASSET, N.Y. — Though a late entrant to a market pummeled by falling prices and cutthroat competition, IceFyre Semiconductor Inc. (Ottawa) believes its first-generation wireless-LAN chip sets have the performance and flexibility to stand apart in the crowded WLAN field.
This week the startup will announce two chip sets — one that meets IEEE 802.11a specs, the other a dual-band 802.11a/b/g chip set — incorporating advanced RF and mixed-signal design techniques that it says will double the range and halve the power of WLAN implementations in consumer, audio/visual and enterprise infrastructure applications.
IceFyre is taking on established WLAN IC players, many of which have announced low-power chip sets in recent weeks. Broadcom and Philips Semiconductors introduced .11b offerings, Agere Systems and Atheros Communications announced .11a/g/b chip sets, and Conexant Systems and Texas Instruments each announced baseband processors.
Backed by $39 million in financing to date, IceFyre will try to rise above the noise on the strength of a patented architecture focused on reducing the peak-to-average power ratio (PAPR) of the 802.11a and .11g standards' orthogonal frequency-division multiplexing (OFDM) access scheme. Cutting the PAPR improves power-amplifier efficiency, and the company says it has implemented further techniques to reduce power and increase range.
The technology has already attracted attention for consumer electronics, with Sharp Corp. planning to incorporate the chip sets in its consumer and A/V lineup.
The first chip to sample is the SureFyre ICE5351, an 802.11a physical layer with an integrated radio and baseband. The PHY connects to the ICE5125 media-access controller via a standard 8-bit interface. The separate MAC "gives us the flexibility we find our customers are demanding," said Mark Roberts, vice president of marketing. Some want to use IceFyre's MAC, some a third-party MAC and others their own design, he said. "If you look at all the standards work going on, they all affect the MAC. By keeping the MAC separate, we can respin it quickly."
Out front in the signal chain is the ICE5352, a combination power amplifier and Chireix combiner implemented in a GaAs chip designed by IceFyre and built by TriQuint Semiconductor Inc.
IceFyre's patented power-amp design, which includes its core intellectual property, achieves a power-added efficiency of up to 35 percent, vs. 12 percent for linear designs that have to back off for OFDM, Roberts said. The PAPR-reduction technique also applies to other multicarrier schemes, such as wideband-CDMA. In WLANs, it allows the SureFyre to deliver up to 23-dBm conducted power at 54 Mbits/second — the maximum conducted power in the middle U-NII band.
"This translates — with reasonable design practices [i.e., using a 4.5 dBi antenna] — to 40 meters at 54 Mbits/s, using a fairly pessimistic path loss coefficient of 3.0," Roberts said. At the same power level, Roberts quoted distances of up to 1.8 miles at 54 Mbits/s in line-of-sight bridging applications with a 17-dBi antenna.
Total system power consumption for the SureFyre is specified at 947 milliwatts at 12 EIRP (effective isotropic radiated power). The peak power is 1.1 W, dropping to 5 mW in sleep mode.
On the receive side, the SureFyre has a guaranteed sensitivity of -70 dBm and a noise figure of 8 dB in the radio. "With these two figures we're up to 7 dB better than the 802.11 specification," said Roberts. "And with an external low-noise amplifier, you can get an additional 1 to 2 dB decrease in the noise figure."
SureFyre also offers per-carrier and per-packet equalization and per-packet antenna diversity, which collectively improve sensitivity by about 10 dB. "We have good tolerance of multipath [interference] indoors, with a delay spread of 150 ns," said Roberts. "Customers really want to see [WLAN technology] cover whole homes."
The dual-band 802.11a/b/g chip, called TwinFyre, does all the baseband processing in the same PHY as SureFyre but uses a separate commodity radio for the 2.45-GHz 802.11b/g component. "The b/g radios are getting quite inexpensive so you can combine the two," Roberts said.
Both chip sets are built in a 0.18-micron RF CMOS process by Taiwan Semiconductor Manufacturing Co. Ltd. The SureFyre is sampling now, with volume production scheduled for the first quarter at less than $20, including the power amp. The TwinFyre will sample by the second quarter of next year, with production scheduled for the third quarter.
