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Question

802.11a - 802.11ac multipath incompatibility

Feb 24, 2018 3:34AM PST

i have a wireless router HP M111 that supports 802.11a for 5Ghz only, it does not have 802.11ac. I am installing a new design with Cisco 3702 APs which have 802.11ac radios. While I know 802.11ac is backward compatible with a, I am wondering if the device might have multipath issues due to the 3 spatial streams coming from the 802.11ac radios?

Discussion is locked

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Clarification Request
Not in a Lab
Feb 24, 2018 7:57AM PST

Not in a lab. I am in a manufacturing production plant where I am about to implement [turn on] the 3702 APs as I mentioned. The HP111's are actually connected to an application for Auto-Guided Vehicles [AGV's].

The 802.11 specs say 802.11ac are backwards compatible with 802.11a radios in the M111's but my worry is, in a real environment with 802.11ac's supporting MIMO and transmitting three spatial streams, and with the older 802.11a radio in the M111's not being MIMO capable, will they stop working because of being overwhelmed by multipath signals?

Or is there something at the data layer that informs the 802.11ac radio not to transmit MIMO when responding? In a multi-device environment, I don't see, or understand anyway, how this would work.

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Have to go with nope.
Feb 24, 2018 8:56AM PST

I see mixes all the time of more than one hotspot. Out of thousands of setups, I can only write that what you asked would be a concern under lab testing for issues.

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Answer
Multipath? Are you in a laboratory?
Feb 24, 2018 7:38AM PST

Most will just deploy and test. I must defer laboratory talk to the lab. As to incompatible, the makers will likely tell you "incompatible" but my view which I will not write more than this is it will work. Not that it will be optimum but only in a lab would you care.