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      1 /* $NetBSD: ieee80211_rssadapt.h,v 1.9 2016/04/08 14:30:47 roy 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  *
     15  * THIS SOFTWARE IS PROVIDED BY David Young ``AS IS'' AND ANY
     16  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
     17  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
     18  * PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL David
     19  * Young BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     20  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
     21  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
     23  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
     26  * OF SUCH DAMAGE.
     27  */
     28 
     29 #ifndef _NET80211_IEEE80211_RSSADAPT_H_
     30 #define _NET80211_IEEE80211_RSSADAPT_H_
     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_expavgctl {
     50 	/* RSS threshold decay. */
     51 	u_int rc_decay_denom;
     52 	u_int rc_decay_old;
     53 	/* RSS threshold update. */
     54 	u_int rc_thresh_denom;
     55 	u_int rc_thresh_old;
     56 	/* RSS average update. */
     57 	u_int rc_avgrssi_denom;
     58 	u_int rc_avgrssi_old;
     59 };
     60 
     61 struct ieee80211_rssadapt {
     62 	/* exponential average RSSI << 8 */
     63 	u_int16_t		ra_avg_rssi;
     64 	/* Tx failures in this update interval */
     65 	u_int32_t		ra_nfail;
     66 	/* Tx successes in this update interval */
     67 	u_int32_t		ra_nok;
     68 	/* exponential average packets/second */
     69 	u_int32_t		ra_pktrate;
     70 	/* RSSI threshold for each Tx rate */
     71 	u_int16_t		ra_rate_thresh[IEEE80211_RSSADAPT_BKTS]
     72 					      [IEEE80211_RATE_SIZE];
     73 	struct timeval		ra_last_raise;
     74 	struct timeval		ra_raise_interval;
     75 };
     76 
     77 /* Properties of a Tx packet, for link adaptation. */
     78 struct ieee80211_rssdesc {
     79 	u_int			 id_len;	/* Tx packet length */
     80 	u_int			 id_rateidx;	/* index into ni->ni_rates */
     81 	struct ieee80211_node	*id_node;	/* destination STA MAC */
     82 	u_int8_t		 id_rssi;	/* destination STA avg RSS @
     83 						 * Tx time
     84 						 */
     85 };
     86 
     87 void	ieee80211_rssadapt_updatestats(struct ieee80211_rssadapt *);
     88 void	ieee80211_rssadapt_input(struct ieee80211com *, struct ieee80211_node *,
     89 	    struct ieee80211_rssadapt *, int);
     90 void	ieee80211_rssadapt_lower_rate(struct ieee80211com *,
     91 	    struct ieee80211_node *, struct ieee80211_rssadapt *,
     92 	    struct ieee80211_rssdesc *);
     93 void	ieee80211_rssadapt_raise_rate(struct ieee80211com *,
     94 	    struct ieee80211_rssadapt *, struct ieee80211_rssdesc *);
     95 int	ieee80211_rssadapt_choose(struct ieee80211_rssadapt *,
     96 	    struct ieee80211_rateset *, struct ieee80211_frame *, u_int, int,
     97 	    const char *, int);
     98 #ifdef IEEE80211_DEBUG
     99 extern int ieee80211_rssadapt_debug;
    100 #endif /* IEEE80211_DEBUG */
    101 
    102 #endif /* !_NET80211_IEEE80211_RSSADAPT_H_ */
    103 
    104