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
33 /* Data-rate adaptation loosely based on "Link Adaptation Strategy
34 * for IEEE 802.11 WLAN via Received Signal Strength Measurement"
35 * by Javier del Prado Pavon and Sunghyun Choi.
36 */
37
38 /* Buckets for frames 0-128 bytes long, 129-1024, 1025-maximum. */
39 #define RAL_RSSADAPT_BKTS 3
40 #define RAL_RSSADAPT_BKT0 128
41 #define RAL_RSSADAPT_BKTPOWER 3 /* 2**_BKTPOWER */
42
43 #define ral_rssadapt_thresh_new \
44 (ral_rssadapt_thresh_denom - ral_rssadapt_thresh_old)
45 #define ral_rssadapt_decay_new \
46 (ral_rssadapt_decay_denom - ral_rssadapt_decay_old)
47 #define ral_rssadapt_avgrssi_new \
48 (ral_rssadapt_avgrssi_denom - ral_rssadapt_avgrssi_old)
49
50 struct ral_rssadapt_expavgctl {
51 /* RSS threshold decay. */
52 u_int rc_decay_denom;
53 u_int rc_decay_old;
54 /* RSS threshold update. */
55 u_int rc_thresh_denom;
56 u_int rc_thresh_old;
57 /* RSS average update. */
58 u_int rc_avgrssi_denom;
59 u_int rc_avgrssi_old;
60 };
61
62 struct ral_rssadapt {
63 /* exponential average RSSI << 8 */
64 u_int16_t ra_avg_rssi;
65 /* Tx failures in this update interval */
66 u_int32_t ra_nfail;
67 /* Tx successes in this update interval */
68 u_int32_t ra_nok;
69 /* exponential average packets/second */
70 u_int32_t ra_pktrate;
71 /* RSSI threshold for each Tx rate */
72 u_int16_t ra_rate_thresh[RAL_RSSADAPT_BKTS]
73 [IEEE80211_RATE_SIZE];
74 struct timeval ra_last_raise;
75 struct timeval ra_raise_interval;
76 };
77
78 /* Properties of a Tx packet, for link adaptation. */
79 struct ral_rssdesc {
80 u_int id_len; /* Tx packet length */
81 u_int id_rateidx; /* index into ni->ni_rates */
82 struct ieee80211_node *id_node; /* destination STA MAC */
83 u_int8_t id_rssi; /* destination STA avg RSS @
84 * Tx time
85 */
86 };
87
88 void ral_rssadapt_updatestats(struct ral_rssadapt *);
89 void ral_rssadapt_input(struct ieee80211com *, struct ieee80211_node *,
90 struct ral_rssadapt *, int);
91 void ral_rssadapt_lower_rate(struct ieee80211com *,
92 struct ieee80211_node *, struct ral_rssadapt *,
93 struct ral_rssdesc *);
94 void ral_rssadapt_raise_rate(struct ieee80211com *,
95 struct ral_rssadapt *, struct ral_rssdesc *);
96 int ral_rssadapt_choose(struct ral_rssadapt *,
97 struct ieee80211_rateset *, struct ieee80211_frame *, u_int,
98 const char *, int);
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