802.11g: 802.11a Meets 802.11b

Source: extremetech

802.11 wireless networking is becoming a confusing alphabet soup of letters, numbers and speeds. Let's break down what 802.11g, the latest wireless variant, actually is.

802.11g is a kind of hybrid of 11a and 11b. It uses the same transmission technology found in 802.11a, which is called Orthogonal Frequency Division Multiplexing (OFDM). This increases the amount of data transmitted in a given time slice. However, unlike 802.11a, which operates in a 5GHz band, 802.11g uses carrier frequency bands that are around 11b's 2.4GHz primary carrier frequency.

The promise of 11g is that it will deliver 802.11a-like data rates, with 802.11b's better transmit distances, and handling of reflections and occlusions. And because it works in the same 2.4GHz frequency, it ought to allow easier interoperability between 802.11b and 802.11g.

802.11g's carrier wave frequency bands, which operate around 2.4GHz, give it better coverage than 802.11a (which uses a 5GHz carrier frequency band). This is because 802.11a's 5GHz carrier frequency suffers from the laws of information theory where frequency, radiated power and distance have an inverse relationship.

In other words, the higher the carrier frequency, the shorter the transmit distance, all other things being equal. 802.11a does increase its transmission power to 50mW, but even so, 802.11a does not handle either longer transmit distances or occluding objects (walls, furniture, etc.) as well as 802.11b.

802.11g also offers backward compatibility with 802.11b, so that you hopefully won't have to toss all the 802.11b gear you've accumulated. But compatibility remains a large question mark across the gamut of 802.11b products, and it's quite likely that not all 802.11b products are will talk to 802.11g access points.

Performance Results: In our tests, we found that 802.11g delivers better than 2X the throughput of 802.11b, although it's well shy of matching 802.11a's performance at close range. But like both a and b, 802.11g still lacks Quality of Service (QoS) provisions. We won't see these until the arrival of the 802.11e spec later this year.

Even with the improved throughput, 802.11g still provides what's called best effort service to all traffic on the wire, whether it's streaming video or copying a large file.

For more about 802.11e, see our recent article from our first roundup of products for building a home media network. What We Tested

We looked at products from two companies, Linksys and Buffalo Technologies....

For more, visit extremetech