FreeBSD/Linux Kernel Cross Reference
sys/net80211/ieee80211_rssadapt.h

     /*      $FreeBSD: releng/8.0/sys/net80211/ieee80211_rssadapt.h 178354 2008-04-20 20:35:46Z sam $        */
     /* $NetBSD: ieee80211_rssadapt.h,v 1.4 2005/02/26 22:45:09 perry Exp $ */
     /*-
      * Copyright (c) 2003, 2004 David Young.  All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or
      * without modification, are permitted provided that the following
      * conditions are met:
      * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above
     *    copyright notice, this list of conditions and the following
     *    disclaimer in the documentation and/or other materials provided
     *    with the distribution.
     * 3. The name of David Young may not be used to endorse or promote
     *    products derived from this software without specific prior
     *    written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY David Young ``AS IS'' AND ANY
     * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
     * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
     * PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL David
     * Young BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
     * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
     * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
     * OF SUCH DAMAGE.
     */
    #ifndef _NET80211_IEEE80211_RSSADAPT_H_
    #define _NET80211_IEEE80211_RSSADAPT_H_
    
    /* Data-rate adaptation loosely based on "Link Adaptation Strategy
     * for IEEE 802.11 WLAN via Received Signal Strength Measurement"
     * by Javier del Prado Pavon and Sunghyun Choi.
     */
    
    /* Buckets for frames 0-128 bytes long, 129-1024, 1025-maximum. */
    #define IEEE80211_RSSADAPT_BKTS         3
    #define IEEE80211_RSSADAPT_BKT0         128
    #define IEEE80211_RSSADAPT_BKTPOWER     3       /* 2**_BKTPOWER */
    
    struct ieee80211_rssadapt {
            struct ieee80211vap *vap;
            int     interval;                       /* update interval (ticks) */
    };
    
    struct ieee80211_rssadapt_node {
            struct ieee80211_rssadapt *ra_rs;       /* backpointer */
            struct ieee80211_rateset ra_rates;      /* negotiated rates */
            int     ra_rix;                         /* current rate index */
            int     ra_ticks;                       /* time of last update */
            int     ra_last_raise;                  /* time of last rate raise */
            int     ra_raise_interval;              /* rate raise time threshold */
    
            /* Tx failures in this update interval */
            uint32_t                ra_nfail;
            /* Tx successes in this update interval */
            uint32_t                ra_nok;
            /* exponential average packets/second */
            uint32_t                ra_pktrate;
            /* RSSI threshold for each Tx rate */
            uint16_t                ra_rate_thresh[IEEE80211_RSSADAPT_BKTS]
                                                  [IEEE80211_RATE_SIZE];
    };
    
    void    ieee80211_rssadapt_init(struct ieee80211_rssadapt *,
                struct ieee80211vap *, int);
    void    ieee80211_rssadapt_cleanup(struct ieee80211_rssadapt *);
    void    ieee80211_rssadapt_setinterval(struct ieee80211_rssadapt *, int);
    void    ieee80211_rssadapt_node_init(struct ieee80211_rssadapt *,
                struct ieee80211_rssadapt_node *, struct ieee80211_node *);
    int     ieee80211_rssadapt_choose(struct ieee80211_node *,
                struct ieee80211_rssadapt_node *, u_int);
    
    /* NB: these are public only for the inline below */
    void    ieee80211_rssadapt_raise_rate(struct ieee80211_rssadapt_node *,
                int pktlen, int rssi);
    void    ieee80211_rssadapt_lower_rate(struct ieee80211_rssadapt_node *,
                int pktlen, int rssi);
    
    #define IEEE80211_RSSADAPT_SUCCESS      1
    #define IEEE80211_RSSADAPT_FAILURE      0
    
    static __inline void
    ieee80211_rssadapt_tx_complete(struct ieee80211_rssadapt_node *ra,
        int success, int pktlen, int rssi)
    {
            if (success) {
                    ra->ra_nok++;
                    if ((ra->ra_rix + 1) < ra->ra_rates.rs_nrates &&
                        (ticks - ra->ra_last_raise) >= ra->ra_raise_interval)
                            ieee80211_rssadapt_raise_rate(ra, pktlen, rssi);
            } else {
                    ra->ra_nfail++;
                    ieee80211_rssadapt_lower_rate(ra, pktlen, rssi);
            }
   }
   #endif /* _NET80211_IEEE80211_RSSADAPT_H_ */

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