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ieee80211_rssadapt.h revision 1.1 
      1 /* $NetBSD: ieee80211_rssadapt.h,v 1.1 2003/10/26 07:56:41 dyoung Exp $ */
      2 /*-
      3  * Copyright (c) 2003, 2004 David Young.  All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or
      6  * without modification, are permitted provided that the following
      7  * conditions are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above
     11  *    copyright notice, this list of conditions and the following
     12  *    disclaimer in the documentation and/or other materials provided
     13  *    with the distribution.
     14  * 3. The name of David Young may not be used to endorse or promote
     15  *    products derived from this software without specific prior
     16  *    written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY David Young ``AS IS'' AND ANY
     19  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
     20  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
     21  * PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL David
     22  * Young BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     23  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
     24  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
     26  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     27  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
     29  * OF SUCH DAMAGE.
     30  */
     31 
     32 /* Data-rate adaptation loosely based on "Link Adaptation Strategy
     33  * for IEEE 802.11 WLAN via Received Signal Strength Measurement"
     34  * by Javier del Prado Pavon and Sunghyun Choi.
     35  */
     36 
     37 /* Buckets for frames 0-128 bytes long, 129-1024, 1025-maximum. */
     38 #define	IEEE80211_RSSADAPT_BKTS		3
     39 #define IEEE80211_RSSADAPT_BKT0		128
     40 #define	IEEE80211_RSSADAPT_BKTPOWER	3	/* 2**_BKTPOWER */
     41 
     42 #define	ieee80211_rssadapt_thresh_new \
     43     (ieee80211_rssadapt_thresh_denom - ieee80211_rssadapt_thresh_old)
     44 #define	ieee80211_rssadapt_decay_new \
     45     (ieee80211_rssadapt_decay_denom - ieee80211_rssadapt_decay_old)
     46 #define	ieee80211_rssadapt_avgrssi_new \
     47     (ieee80211_rssadapt_avgrssi_denom - ieee80211_rssadapt_avgrssi_old)
     48 
     49 struct ieee80211_rssadapt {
     50 	/* exponential average RSSI << 8 */
     51 	u_int16_t		ra_avg_rssi;
     52 	/* Tx failures in this update interval */
     53 	u_int32_t		ra_nfail;
     54 	/* Tx successes in this update interval */
     55 	u_int32_t		ra_nok;
     56 	/* exponential average packets/second */
     57 	u_int32_t		ra_pktrate;
     58 	/* RSSI threshold for each Tx rate */
     59 	u_int16_t		ra_rate_thresh[IEEE80211_RSSADAPT_BKTS]
     60 					      [IEEE80211_RATE_SIZE];
     61 	struct timeval		ra_last_raise;
     62 	struct timeval		ra_raise_interval;
     63 };
     64 
     65 /* Properties of a Tx packet, for link adaptation. */
     66 struct ieee80211_rssdesc {
     67 	u_int			 id_len;	/* Tx packet length */
     68 	u_int			 id_rateidx;	/* index into ni->ni_rates */
     69 	struct ieee80211_node	*id_node;	/* destination STA MAC */
     70 	u_int8_t		 id_rssi;	/* destination STA avg RSS @
     71 						 * Tx time
     72 						 */
     73 };
     74 
     75 void	ieee80211_rssadapt_updatestats(struct ieee80211_rssadapt *);
     76 void	ieee80211_rssadapt_input(struct ieee80211com *, struct ieee80211_node *,
     77 	    struct ieee80211_rssadapt *, int);
     78 void	ieee80211_rssadapt_lower_rate(struct ieee80211com *,
     79 	    struct ieee80211_node *, struct ieee80211_rssadapt *,
     80 	    struct ieee80211_rssdesc *);
     81 void	ieee80211_rssadapt_raise_rate(struct ieee80211com *,
     82 	    struct ieee80211_rssadapt *, struct ieee80211_rssdesc *);
     83 
     84