Marketing Hype vs Reality

I ongoing to think approximately the make property this might cause our Wireless LANs in the prospect as 802.11ac Wave 2 in on the horizon meant for then time.
Though I, like many of you, are intrigued and impressed by the technical complexity and geek-coolness of MU-MIMO… I ongoing to think through approximately of the implications and how actuality is ready to trump marketing advertise.

Those marketing Wave2 as the “Panacea” of Wi-Fi congestion will be proven sin. (I added the word Panacea emphatically meant for my isolated Sam Clements)

Here are approximately of the issues I forecast with the intention of will frustrate all the marketing mechanism advertise surrounding Wave 2.
Not Enough Radio Chains

We were imaginary to contain 4×4:4 in 802.11n – and by this schedule it isn’t even on the horizon meant for a spacious variety of reasons. I’m predicting 802.11ac’s give your word of an 8×8:8 are emphatically a speculative limit as well. We’ll be remorseless pushed to walk much more than 4X4:4 unacceptable of our production Enterprise-class Wi-Fi gear. Thus many of the repayment of MU-MIMO will be somewhat truncated by minimizing viable radio-chains.

Distance Limitations

We are already sorely incomplete in our 256-QAM distance limitations based on the extraordinarily prominent SNR rations to argue a clean adequate RF SINR differential to keep 256-QAM signaling devoid of inducing errors. Happening today’s hard generally vendors are touting sub-10m distances already meant for their MCS charge requiring 256-QAM. (my real-world hard seats this down under 8m)

When you let down the Tx power by splitting rancid approximately of the spatial streams to support multiple clients, you are effectively lowering the SINR to single client diplomacy. For model, lets say you had a 4×4:4 skilled 802.11ac Wave 2 Access Point, and you were servicing two clients. Each client would right away receive the RSSI energy of individual two of the spatial streams, as a result effectively giving the client a -3dB let down RSSI. (When compared to receiving all 4 spatial streams and using built-in MRC to garner the highest viable SNR from the Transmitted radios)

This -3dB loss in RSSI would let down the in effect range of 256-QAM even foster.

Drop in Data Rates

So set a exclusive area everywhere Wave 1 – SU-MIMO was in place, rotary on Wave 2 MU-MIMO may possibly potentially go down the client’s associated data charge by a enormous margin by dropping unacceptable of 256-QAM and lowering to a 64-QAM MCS rate as a replacement for. This in twist would let down the unfilled schedule in the frequency – all client right away takes longer to transmit – as a result lowering the ability of the frequency and lowering the figure of clients with the intention of can be serviced by several single AP.

Just this -3dB loss in SINR isolated would indicate we must be very cautious indeed in believing all the marketing advertise associated with Wave 2 802.11ac. Read the marketing literature with a speck of caution and a skeptical eye to the enormous increases in Wireless LAN throughput.

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