xref: /freebsd/sys/net80211/ieee80211_rssadapt.h (revision f7c4bd95ba735bd6a5454b4953945a99cefbb80c)
1 /*	$FreeBSD$	*/
2 /* $NetBSD: ieee80211_rssadapt.h,v 1.4 2005/02/26 22:45:09 perry Exp $ */
3 /*-
4  * Copyright (c) 2003, 2004 David Young.  All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or
7  * without modification, are permitted provided that the following
8  * conditions are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above
12  *    copyright notice, this list of conditions and the following
13  *    disclaimer in the documentation and/or other materials provided
14  *    with the distribution.
15  * 3. The name of David Young may not be used to endorse or promote
16  *    products derived from this software without specific prior
17  *    written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY David Young ``AS IS'' AND ANY
20  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
22  * PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL David
23  * Young BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
24  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
25  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
27  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
28  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
30  * OF SUCH DAMAGE.
31  */
32 #ifndef _NET80211_IEEE80211_RSSADAPT_H_
33 #define _NET80211_IEEE80211_RSSADAPT_H_
34 
35 /* Data-rate adaptation loosely based on "Link Adaptation Strategy
36  * for IEEE 802.11 WLAN via Received Signal Strength Measurement"
37  * by Javier del Prado Pavon and Sunghyun Choi.
38  */
39 
40 /* Buckets for frames 0-128 bytes long, 129-1024, 1025-maximum. */
41 #define	IEEE80211_RSSADAPT_BKTS		3
42 #define IEEE80211_RSSADAPT_BKT0		128
43 #define	IEEE80211_RSSADAPT_BKTPOWER	3	/* 2**_BKTPOWER */
44 
45 struct ieee80211_rssadapt {
46 	struct ieee80211vap *vap;
47 	int	interval;			/* update interval (ticks) */
48 };
49 
50 struct ieee80211_rssadapt_node {
51 	struct ieee80211_rssadapt *ra_rs;	/* backpointer */
52 	struct ieee80211_rateset ra_rates;	/* negotiated rates */
53 	int	ra_rix;				/* current rate index */
54 	int	ra_ticks;			/* time of last update */
55 	int	ra_last_raise;			/* time of last rate raise */
56 	int	ra_raise_interval;		/* rate raise time threshold */
57 
58 	/* Tx failures in this update interval */
59 	uint32_t		ra_nfail;
60 	/* Tx successes in this update interval */
61 	uint32_t		ra_nok;
62 	/* exponential average packets/second */
63 	uint32_t		ra_pktrate;
64 	/* RSSI threshold for each Tx rate */
65 	uint16_t		ra_rate_thresh[IEEE80211_RSSADAPT_BKTS]
66 					      [IEEE80211_RATE_SIZE];
67 };
68 
69 void	ieee80211_rssadapt_init(struct ieee80211_rssadapt *,
70 	    struct ieee80211vap *, int);
71 void	ieee80211_rssadapt_cleanup(struct ieee80211_rssadapt *);
72 void	ieee80211_rssadapt_setinterval(struct ieee80211_rssadapt *, int);
73 void	ieee80211_rssadapt_node_init(struct ieee80211_rssadapt *,
74 	    struct ieee80211_rssadapt_node *, struct ieee80211_node *);
75 int	ieee80211_rssadapt_choose(struct ieee80211_node *,
76 	    struct ieee80211_rssadapt_node *, u_int);
77 
78 /* NB: these are public only for the inline below */
79 void	ieee80211_rssadapt_raise_rate(struct ieee80211_rssadapt_node *,
80 	    int pktlen, int rssi);
81 void	ieee80211_rssadapt_lower_rate(struct ieee80211_rssadapt_node *,
82 	    int pktlen, int rssi);
83 
84 #define	IEEE80211_RSSADAPT_SUCCESS	1
85 #define	IEEE80211_RSSADAPT_FAILURE	0
86 
87 static __inline void
88 ieee80211_rssadapt_tx_complete(struct ieee80211_rssadapt_node *ra,
89     int success, int pktlen, int rssi)
90 {
91 	if (success) {
92 		ra->ra_nok++;
93 		if ((ra->ra_rix + 1) < ra->ra_rates.rs_nrates &&
94 		    (ticks - ra->ra_last_raise) >= ra->ra_raise_interval)
95 			ieee80211_rssadapt_raise_rate(ra, pktlen, rssi);
96 	} else {
97 		ra->ra_nfail++;
98 		ieee80211_rssadapt_lower_rate(ra, pktlen, rssi);
99 	}
100 }
101 #endif /* _NET80211_IEEE80211_RSSADAPT_H_ */
102