Return-path: Received: from mail-gw0-f46.google.com ([74.125.83.46]:38537 "EHLO mail-gw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754704Ab1F3A5g convert rfc822-to-8bit (ORCPT ); Wed, 29 Jun 2011 20:57:36 -0400 Received: by gwaa18 with SMTP id a18so679396gwa.19 for ; Wed, 29 Jun 2011 17:57:35 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: Date: Thu, 30 Jun 2011 08:57:35 +0800 Message-ID: (sfid-20110630_025744_670002_680611CA) Subject: Re: [ath9k-devel] STBC functionality details request From: Adrian Chadd To: Fred Matthews Cc: ath9k-devel@lists.ath9k.org, linux-wireless@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-wireless-owner@vger.kernel.org List-ID: I think things are a bit confusing, but here goes. The earlier NICs only support either RX STBC (pre ar9280?) or TX 1-stream STBC (ar9280 or above). Multi-stream STBC isn't in any of the AR9xxx NICs. It may be in the AR9287; it may be in the AR9300/AR9400. I've not looked. I bet what you're finding is: * with STBC enabled, for single stream rates, it's tx'ing using STBC. It just sets a bit in the TX descriptor. * with STBC enabled, for multi-stream rates, it's not setting the STBC TX bit and it's instead sending it as a 2 stream packet w/out STBC. The AR9280 is not a one stream NIC - it's a two stream TX/RX NIC. (Unless you're using the AR9281 - which is an AR9280 1T2R stream device.) The AR9285 is a 1x1 stream device. The AR9287 is a 2x2 stream device. HTH, Adrian > I am using STBC (Space Time Block Coding) 1 stream NICs like the AR9280.I would be very grateful someone can kindly advise on how exactly STBC(transmits multiple copies of a data across each of the antennas)?works in ath9k. > I ask this because when I enable STBC 1-stream, the driver seems to uses Space division multiplexing (can this be disabled/enabled?), since the rate is over 150Mbps. > When is STBC activated ?, ...Does Minstrel/ath9k rate adaptation?mechanism?find first check if Spatial multiplexing is better, if not uses STBC ? > Thank you for your time > _______________________________________________ > ath9k-devel mailing list > ath9k-devel@lists.ath9k.org > https://lists.ath9k.org/mailman/listinfo/ath9k-devel >