First of all, if you still are running an 802.11b wireless network, you should definitely consider replacing all of your wireless gear with at least 802.11g products. Even the least-expensive 802.11g current-generation chipsets have improved receive sensitivity that can definitely help improve wireless coverage. And you'll also get support for WPA2; the most current wireless security protocol.
But if you already are running an 802.11g WLAN, what other options do you have? Ever since Texas Instruments turned its PBCC (Packet Binary Convolutional Coding) modulation technique that failed to be included in 802.11g into "enhanced" 802.11b, manufacturers have been making proprietary tweaks to wireless standards in order to increase wireless LAN throughput and range.
I looked at a few of these techniques back in this 2004 article, and concluded that both Atheros' Super-G and Airgo's True MIMO actually did help. Super G is still around in many products, and is generally indicated by the use of "108 Mbps" either in the product name or noted somewhere in the product spec.
But I found Airgo's MIMO, in the form of Belkin's Pre-N router and card to be the more impressive technology. Although Airgo's technology was taken off the market by Qualcomm's purchase of the company, MIMO lives on in the form of 802.11n.
So what kind of improvement can you expect from a move to Super G or draft 11n? Figures 2 and 3 show composite throughput vs. path loss plots generated using our Wireless Performance Charts for downlink and uplink for three D-Link products.
NOTE: See this article for an explanation of how Path Loss relates to distance.
Both the entry-level WBR-2310 (which began life as the DI-604) and DGL-4300 are based on Super-G. But the 2310 defaults to disabling the "Turbo" (channel-bonded) mode that provides most of Super-G's throughput enhancement, while the 4300 defaults to Turbo enabled. The DIR-655 is a 802.11n Draft 2.0 certified router using Atheros XSPAN silicon.
Figure 2: 11g, Super G, Draft 11n comparison - downlink
The higher throughput that both Super G Turbo and draft 11n MIMO provide over standard 802.11g is obvious. But the range story is a bit different. All of the test runs were made until the router and card disconnected, which you can see is within one 3 dB test step, which is not that big a difference.
Even more interesting is the uplink plot, which shows Super-G Turbo's throughput falling below that of standard 11g. Also note the difference in the X axis scale, which is 3 dB smaller for uplink.
Figure 3: 11g, Super G, Draft 11n comparison - uplink
Broadcom's Afterburner throughput enhancement is a bit of a different story. Figure 4 shows a downlink comparison between the Linksys WRT54G V5 and WRT54GS V7, i.e. without and with Afterburner.
Figure 4: 11g, Afterburner comparison - downlink
You can see that in both directions, the throughput enhancement doesn't last long and then falls back to lower throughput than you get with the standard Broadcom 11g chipset! Also note that, once again, there is only 3 dB of difference in Path Loss performance.
Figure 5: 11g, Afterburner comparison - uplink
The main take-away from this is that newer technologies may provide more of an improvement in speed than range. So if you were getting no connection with your current gear, that still might be the case after you upgrade. But if you were getting an intermittent and/or slow connection with your old stuff, newer gear might move you from an annoying wireless experience to one that's (relatively) trouble free.
That wraps it up for this time. In the next installment, I'll look at upgrading AP antennas. In the meantime, if you're wondering whether changing your wireless client adapter can improve performance, take a look at this article.