Walkaround Performance - 2.4 GHz
I started to test the 1522 as a pair using my five location walk-around test by connecting one of the pair set to Bridge mode to my notebook, but remembered that it doesn't have a gigabit Ethernet interface. So I installed a Netgear GA511 Gigabit Ethernet Cardbus card to solve that problem, then plugged in the 1522. The other 1522 was set to AP mode and connected to my LAN's Netgear GS108 gigabit switch. All testing was done on Channel 1 with no encryption.
I then left the AP mode 1522 in the lab and walked the Bridge mode 1522 and notebook around. Figures 6 and 7 show down and uplink throughput for locations 1-4 (the pair were unable to connect in Location 5) in the 2.4 GHz, 20 MHz bandwidth mode that the 1522 defaults to out of the box.
As is typical of many draft 11n products, up and downlink throughput are not equal. Figures 6 and 7 show best cases of 53.1 Mbps downlink and 33.4 Mbps uplink in Location 1. You can also see that throughput is not steady and really falls off quickly with distance for uplink.
Figure 6: Walkaround wireless throughput - 2.4 GHz down, 20 MHz mode
Since the 1522 does not provide a readout of link rate, I couldn't confirm my suspicion that excessive link rate adjustment is the culprit for the throughput variation. I have no explanation for the significantly lower uplink performance, particularly because there is the same 2T2R (2 transmit, 2 receive channels) radio at both ends of the link.
Figure 7: Walkaround wireless throughput - 2.4 GHz up, 20 MHz mode
Things significantly improved for uplink when I switched to the Auto 20/40 MHz mode, which I verified using 40 MHz channel width during the tests by using a Cognio (now Cisco) Spectrum Expert spectrum analyzer. Downlink speed (Figure 8) improved to 70.6 Mbps and smoothed out at Locations 2 and 3.
Note that the Location 4 connection became very erratic, which accounts for the very low 1.6 Mbps throughput. That average number is a bit misleading, since it appears that the connection was just about dead 6 seconds into the 1 minute run.
Figure 8: Walkaround wireless throughput - 2.4 GHz down, 40 MHz mode
Uplink throughput also improved to 53.8 Mbps. But, again, there was a price to pay at Location 4. This time, I couldn't even maintain a connection, which accounts for the "No Results" reading in Figure 9.