Performance Improvement - 11g and True MIMO
My last series of tests investigated the claim that the True MIMO technology improves the performance of non-True MIMO wireless gear. Linksys is pretty fuzzy in their performance improvement claim, saying only that standard Wireless-G and -B equipment will "work better" when used with SRX stuff. Belkin takes a more aggressive tack, saying "Using a Belkin Pre-N Router or Card with an older 802.11g or 802.11b networking product increases wireless coverage up to 20%".
I didn't get into calculating percentages, instead taking a simpler approach. I set up a Linksys WRT54G (original version) router (upgraded to 2.04.4 firmware), inserted a WPC54G original version card (with WinXP 3.30.15.0 driver) into my Dell Inspiron 4100 WinXP Home SP2 notebook, and ran my standard four location test. The results for the uplink direction are in Figure 26 and show a significant drop in performance (under 8Mbps) for any location that had a wall or two between client and router.
Figure 26: Four Location uplink throughput - 11g STA and AP
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Figure 27 shows another four location uplink run, but this time with the WRT54GX router substituted for the WRT54G. You can see that the best-case Location 1 throughput doesn't improve, but that two out of three other locations improved to almost par with Location 1, with the remaining Location (3) almost doubling in throughput.
Figure 27: Four Location uplink throughput - 11g STA, True MIMO AP
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Figure 28 shows what happens when the True MIMO magic is applied on the client end, with the WRT54G is put back into place and a WPC54GX client substituted for the WPC54G. All Locations (except for Location 1) are again improved, if not a little more consistently than in the True MIMO router case.
Figure 28: Four Location uplink throughput - True MIMO STA, 11g AP
(click on image to enlarge)
I should note that while the actual numbers varied, I achieved similar results in the downlink direction for both the above combinations.