The best replacement for 802.11b is 802.11a.

The best alternatives to 802.11b are rated as following:
★★★★★  802.11a
★★★★★  802.11g
★★★★  802.11n
★  54g
★  802.11b
★  802.11ac
★  802.11
★  ieee 802.11g
  11g

Your alternative for 802.11b is not listed? Suggest!
Speaking about 802.11b, one probably shouldn't forget about 802.11g.

Other search terms related to 802.11b and their ratings are:
★★★★★ 802.11g
You have in mind a companion for 802.11b and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of 802.11b in all years. Click on graph for more.
802.11b
802.11a
802.11g