Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-0.7 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_MED,SPF_PASS,SUBJ_ALL_CAPS,T_DKIM_INVALID autolearn=ham autolearn_force=no version=3.4.0 X-Spam-DCC: EATSERVER: mailn 1166; Body=2 Fuz1=2 Fuz2=2 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by lipkowski.org (8.14.4/8.14.4/Debian-8+deb8u1) with ESMTP id v1R9VOkT011447 for ; Mon, 27 Feb 2017 10:31:26 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1ciHaR-0004MW-6S for rs_out_1@blacksheep.org; Mon, 27 Feb 2017 09:27:19 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1ciHaQ-0004MN-2w for rsgb_lf_group@blacksheep.org; Mon, 27 Feb 2017 09:27:18 +0000 Received: from porthos.netcom.co.uk ([217.72.171.73]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.87) (envelope-from ) id 1ciHaM-0000FA-Nl for rsgb_lf_group@blacksheep.org; Mon, 27 Feb 2017 09:27:16 +0000 X-DKIM-Result: Domain=abelian.org Result=Signature OK DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=abelian.org ; s=default; h=Content-Transfer-Encoding:Content-Type:In-Reply-To: MIME-Version:Date:Message-ID:From:To:References:Reply-To:Subject:Sender:Cc: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=h0qiY9EisKBuLBSf8CiCNdADasfN9Q1SRmNid/xH18c=; b=ZRPa//ckkaoo0YkLwypJeITd+J HLpKBBVxoeURgYdXrk61jD//6gexHqHX9BkymSNoKJ8vdzcF7+os2VPcbE4P6s7u3J6u5ugGxpx0z 7T8hr6RD4X8WKoDO+reqL4Q2SNeXjYDVfD2u/LCjIu84o4ct53bB98ghpxSwUl2XYeuw=; Received: from i-194-106-52-83.freedom2surf.net ([194.106.52.83]:60624 helo=pn.abelian.org) by porthos.netcom.co.uk with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.88) (envelope-from ) id 1ciHaL-0004uC-KI for rsgb_lf_group@blacksheep.org; Mon, 27 Feb 2017 09:27:13 +0000 Received: from [127.0.0.1] (localhost [127.0.0.1]) by pn.abelian.org (Postfix) with ESMTP id 519D3400068 for ; Mon, 27 Feb 2017 09:27:12 +0000 (UTC) References: <58B34590.3030802@posteo.de> <58B34924.6060005@posteo.de> <81b61b29-0b37-3e1c-1a42-f9153a1c7870@abelian.org> To: rsgb_lf_group@blacksheep.org From: Paul Nicholson Message-ID: Date: Mon, 27 Feb 2017 09:27:12 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: <81b61b29-0b37-3e1c-1a42-f9153a1c7870@abelian.org> X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - porthos.netcom.co.uk X-AntiAbuse: Original Domain - blacksheep.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - abelian.org X-Get-Message-Sender-Via: porthos.netcom.co.uk: authenticated_id: catchall@abelian.org X-Authenticated-Sender: porthos.netcom.co.uk: catchall@abelian.org X-Scan-Signature: 6ffbd2c9950b634d6cc91f9565b01a8b Subject: Re: VLF: 16K19A? Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Scanned-By: MIMEDefang 2.75 Status: RO X-Status: X-Keywords: X-UID: 10733 A quick trial of 16K19: I just put together my best two rate 1/8 K=19 codes to make a 1/16 K=19 polynomial set and ran a comparison test using 12 char messages at -0.5dB Eb/N0. Decode success rates with optimum list length: 8K19A 69.8 % 16K19T1 67.4 % 8K21A 74.1 % This is typical. The two 1/8 codes are not dissimilar enough to see a performance gain when used together. It usually takes many trials of different combinations to find one that shows some coding gain. I have 147 reasonable 1/8 K=19 codes, so plenty of permutations to try. The method I use is to put pairs of 1/8 codes together and calculate the first 30 or 40 terms of the distance spectrum. The pairs that have the best spectrum then get a full test. I can also add to the list of 8K19 codes by combining 4K19 and so on. This is a lot quicker than just testing random 1/16 polynomials. It's nearly 3 years since I last ran the 'code factory' and I can probably make some improvements to the process now. Certainly the PCs are more powerful. Incidentally the 'A' in 8K19A just labels a particular polynomial. If a better one turns up, it'll go in the menu as 8K19B and so on. -- Paul Nicholson --