The typical peak throughput (sustained data rate) of an 802.11b wireless connection under ideal conditions for end user data is roughly 4-5 Mbps. This level of performance assumes a wireless client in very close proximity (within a few meters) of the base station or other communication endpoint. Due to the distance-sensitive nature of Wi-Fi signaling, 802.11b throughput numbers will decrease the client moves further away from the base station.
Why The Big Difference Between Real and Theoretical 802.11b Speeds?
The large difference between theoretical and actual data rates for 802.11b is due primarily to protocol overhead. Wi-Fi generates a relatively large amount of traffic to maintain connections, coordinate the sending and acknowledgement of messages, and maintain other private state information. Throughput also decreases when interference in the 802.11b signal range (2.4 GHz) is present. Interference often causes re-transmissions due to data corruption or packet loss.
What About 22 Mbps 802.11b?
Some 802.11b Wi-Fi products claimed to support 22 Mbps bandwidth. Vendors created these proprietary variations of 802.11b by extending the technology by various non-standard methods. The actual throughput of 22 Mbps 802.11b networks is not double that of ordinary 802.11b network, although typical peak throughput may increase up to roughly 6-7 Mbps.
802.11b Speed - The Bottom Line
While peak data rates may be achievable at times, and a few households might have upgraded to 22 Mbps gear, many 802.11b home network links typically run at 2-3 Mbps. This is faster than some types of home Internet connections, but is increasingly too slow of a speed for modern wireless networking.
Finally, the perceived "speed" of a network is determined not only by available bandwidth but also by network latency.→ More - Introduction to Computer Network Speed