What 802.11 n tech specs mean

摘要

We established in the last newsletter that you need multiple transmit and receive antennas working in parallel (a.k.a."MIMO" technology) to conduct spatial multiplexing. We also learned that spatial multiplexing is a mandatory component of the 802.11 n standard and is the primary means to 802.11 n's increased throughput promise. But what's the ultimate difference in so-called 2×2 and 2×3 architectures, if they both support two spatial streams? Bottom line, the extra receive antenna increases the range at which you might enjoy a given throughput. Or, it increases throughput at a given range. But let's take it from the top. You'll recall that spatial multiplexing involves multiple antennas separately sending different flows of separately encoded signals over the air at the same time. By multiplexing the signals over a wireless path, more data gets through. Simplistically N transmitting antennas send to N receiving antennas, and each receiver detects a unique stream, resulting in an N-fold increase in throughput.