Return-path: Received: from mail.neratec.com ([46.140.151.2]:48754 "EHLO mail.neratec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750930AbdE3N34 (ORCPT ); Tue, 30 May 2017 09:29:56 -0400 Subject: Re: [PATCH] Per chain RSSI reporting To: Ben Greear , Norik Dzhandzhapanyan , Adrian Chadd References: <21095854-07c7-7586-6a6e-e60c11932b84@candelatech.com> <8e314337-a1f0-5ed4-aa90-3f1a0e2d09fc@ethertronics.com> <50e245a7-60ad-39f1-920e-e8edf5d9a5ab@candelatech.com> <82088c50-f800-9d5c-8ccf-879f4b425e66@candelatech.com> Cc: "ath10k@lists.infradead.org" , "linux-wireless@vger.kernel.org" From: Matthias May Message-ID: <2bc35b78-97b4-bdd8-d8dd-6ec59fa9dbd0@neratec.com> (sfid-20170530_153000_121201_304E5313) Date: Tue, 30 May 2017 15:23:05 +0200 MIME-Version: 1.0 In-Reply-To: <82088c50-f800-9d5c-8ccf-879f4b425e66@candelatech.com> Content-Type: text/plain; charset=windows-1252 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 27/05/17 23:49, Ben Greear wrote: > On 05/27/2017 02:41 PM, Norik Dzhandzhapanyan wrote: >> Yes ~6dB > > If a packet is sent on 1 chain with ath10k firmware (9880 hardware, specifically, but probably > others as well), it will be around 6db higher on that particular chain > than if the rate-control sends it on all three chains. > > Are you measuring on a single chain, or on all of the chains at once and adding > the power? > > I think we would need more detailed reporting using a good third-party device before > smoothing and RSSI. > > Thanks, > Ben > >> Also noteworthy is that if you measure in a cabled environment and add the signal from multiple chains with a combiner you will probably measure the power wrong. The reason for this is that the cyclic shift diversity doesn't work well in a 2 dimensional environment (cable) compared to the 3 dimensional environment (air). BR Matthias >> >> From: Ben Greear >> Sent: Saturday, May 27, 2:38 PM >> Subject: Re: [PATCH] Per chain RSSI reporting >> To: Norik Dzhandzhapanyan, Adrian Chadd >> Cc: ath10k@lists.infradead.org, linux-wireless@vger.kernel.org >> >> >> On 05/27/2017 12:25 PM, Norik Dzhandzhapanyan wrote: > We see this inconsistent/incorrect reporting in our RF chamber. >> How different are the values, and did you sniff with a third-party device to see if it sees the same spikes in RSSI? >> Thanks, Ben > > Norik > > On 05/27/2017 09:39 AM, Adrian Chadd wrote: >> On 27 May 2017 at 09:07, Ben Greear wrote: >> >>> At low encoding rates, especially if it switches to a single-chain encoding, >>> maybe the on-air signal really is >> stronger? >>> >>> Have you verified in some other manner than the signals reported by ath10k >>> are >>> wrong? >> >> Hiya, >> >> So yeah, multipath, higher TX rates == weaker TX signal, TPC, etc are >> all interesting to know about at >> the receiver. it's hard to separate >> that out from the noise sometimes, but in some controlled deployments >> its >> really obvious. >> >> >> >> -adrian >> >> > > > The contents of this transmission are Ethertronics Inc. Confidential >> and may contain proprietary or legally privileged >> information which may not be disclosed, copied or distributed without the express written consent of Ethertronics Inc. >> The information is intended to be for the use of the individual or entity named on this transmission. If you are not >> the intended recipient, be aware that any disclosure, copying, distribution or use of the contents of this information >> is prohibited. If you have received this transmission in error, please notify us by telephone immediately so that we >> can arrange for the retrieval of the original documents at no cost to you. Alternatively, notify the sender by >> replying to this transmission and delete the message without disclosing it. Thank you > -- Ben Greear Candela >> Technologies Inc http://www.candelatech.com >> >