1 /* $FreeBSD: src/sys/net80211/ieee80211_rssadapt.h,v 1.1 2008/04/20 20:35:44 sam Exp $ */
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
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