Xirrus has received a preliminary patent on a new RF shaping capability that allows the companys high-capacity Wi-Fi antennas to significantly improve signal coverage while also reducing signal leakage beyond defined borders, company officials told eWEEK.
The Sharp Cell technology, which is available now, builds on the Xirrus sectored antenna design that already provides significant improvements in available Wi-Fi bandwidth, company officials said. The new technology allows packet-by-packet control of the signal so that the radio frequency energy goes exactly where its needed, and not where its not needed.
“Weve found that one of the issues that happens very often in a Wi-Fi environment is that you tend to have a lot of bleed [from] access point to access point,” said John DiGiovanni, director of marketing at Xirrus, in Westlake Village, Calif. He said that by varying the transmit power packet by packet, the coverage pattern can become cleaner and better defined.
DiGiovanni said that the control capability also means that the Xirrus access points can provide improved range. “When youre transmitting a packet at a higher data rate, the encoding scheme becomes much more complex,” he explained. He said that means that the receiver needs to be closer to the access point than is necessary at lower data rates that do not have such a complex encoding scheme. “The edge of the cell tends to be defined by the data rate,” he said. He said that the new packet-by-packet control lets the receiver be farther from the antenna while still keeping the data rates high.
The new control capability also reduces interference to neighboring Wi-Fi networks, DiGiovanni said. “By better defining the coverage area and limiting the interference outside the coverage area, you provide a good neighbor policy,” he added.
“The idea is to control power on a sector basis,” said Craig Mathias, founder of the Farpoint Group. “Controlling power is important on any sort of Wi-Fi system,” he added, “but on a sectorized antenna its really important. If youre looking for a way to provision a lot in a small space, this is a good way.”
“From an IT standpoint, the idea is to be able to provision a lot of capacity in one location,” Mathias explained. “In theory, you could have 16 simultaneous channels, and have 86M bps in one location,” he said. He explained that this makes it different from simply using a lot of Wi-Fi access points. “You cant just put 16 access points next to each other because they will interfere,” he said. “The Xirrus unit is designed for that.”
DiGiovanni said that the new Xirrus units will be sold at the same price as the previous version of the antenna.
Xirrus also announced on Dec. 12 that it is offering an 802.11n upgrade guarantee. According to DiGiovanni, this means that by paying a premium on the price of their devices, customers are guaranteed to receive the 11n upgrade when it becomes available. He said that the upgrade guarantee will cost 30 percent of the cost of the Xirrus device if purchased initially, or 15 percent of the purchase price each year over three years.