Cell phones to get fast Wi-Fi chip
Yet another phone feature.
By Peter Judge | Published: 08:15, 09 December 2008
Broadcom has launched a chip that combines 802.11n WLAN and Bluetooth for use in phones and other handheld devices.
The 802.11n draft standard's best known feature is the ability to support multiple streams of data on a single radio channel using multipath reflections, but this cannot be easily supported on mobile phones, which do not have room for the widely spaced antennas the feature requires. There is, however, a single stream option, which increases transfer rates using other parts of the 802.11n standard.
"Single stream 802.11n can give up to 50m bits per second of real throughput," said Chris Bergey, director of Broadcom's embedded wireless line of business. "In particular, space time block codes give improved diversity and eliminate dead spots inside a building."
The combo chip, the BCM4329, will be in volume production in 2009 and available in products by the end of 2009, after which time, Bergey expects 802.11n to become widespread in phones, as the chip will be cheaper and more power efficient than existing 802.11g chips.
"It will use less energy in Joules per bit, as it can do transfers faster," Bergey said. "802.11n aggregates packets, so the devices have more time to go to sleep between transactions."
"Wireless LAN is becoming popular in phones thanks to full HTML browsers as seen on the iPhone," said Bergey, who added there was also interest in using it for a personal-area-network in which Bluetooth uses Wi-Fi as an "alternative MAC/PHY" or AMP to transmit media files quickly: "Bluetooth does a great job of setting up a piconet, whereas wireless LAN is difficult to set up ad hoc."
As well as the usual 2.4GHz band, the chip can support Wi-Fi in the 5GHz which is less crowded and likely to become increasingly important.
The module can also share media using an FM transmit function allowing it to stream audio to nearby radio receivers such as car stereos.
