Broadcom's Xpress boosts throughput for g, and mixed b/g: Broadcom joins Intersil and Atheros with technology that allows longer packets (thus reducing overhead) to improve throughput. The twist? Broadcom says they're toeing the 802.11e (Quality of Service or QoS) line to ensure that when 802.11e is ratified, their products will already be more or less compatible.
The improvements, they say, are up to 27 percent for pure 802.11g networks and a remarkable 74 percent for mixed b/g networks. Packets in g are, by default, shorter in duration than in b because g is faster at sending the same data. Increase the g packet time duration to the same as a b packet and you decrease the nonsense (overhead bits) in negotiating time slots for putting that packeton the air, thus improving throughput.
Even better, the Broadcom approach works even in half duplex: that is, if you have a client or access point that has their Xpress code built in, the packets are sped up outbound from those devices, so you get at least some of the improvement. Existing 802.11b/g adapters can interpret these new packets.
Atheros, Intersil, and Texas Instruments all have their own throughput improvements, but they're proprietary between their own equipment -- of course, they could change, too, since packets are constructed via firmware instructions, not, typically, hardwired circuits. (Agere is apparently toeing the 802.11e line, however.)
(Update: Intersil wrote in to correct the above. They said that they're 100 percent standards compliant, which is tricky given that 802.11e isn't yet a standard. But I know what they mean. The question is, of course, whether any of this stuff, Broadcom and otherwise, will deliver the packet bursting advantages in heterogeneous environments before 802.11e ratification. The answer is probably yes.)
This story was embargoed until tomorrow (that is, disclosed to press under conditions that it not be written about until a certain date and time), so I'm not sure who broke that embargo.