9c65c69cd6
Adaptation Strategy for IEEE 802.11 WLAN via Received Signal Strength Measurement" by Javier del Prado Pavon and Sunghyun Choi. This module should provide faster adaptation and higher throughput than Lucent's rate-adaptation scheme. Individual drivers need to be modified to use this module. Patches for wi(4) are forthcoming.
211 lines
7.0 KiB
C
211 lines
7.0 KiB
C
/* $NetBSD: ieee80211_rssadapt.c,v 1.1 2003/10/26 07:56:41 dyoung Exp $ */
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/*-
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* Copyright (c) 2003, 2004 David Young. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or
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* without modification, are permitted provided that the following
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* conditions are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials provided
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* with the distribution.
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* 3. The name of David Young may not be used to endorse or promote
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* products derived from this software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY David Young ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL David
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* Young BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
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* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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* OF SUCH DAMAGE.
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*/
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#include <sys/param.h>
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#include <sys/types.h>
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#include <sys/kernel.h> /* for hz */
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#include <net/if.h>
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#include <net/if_media.h>
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#include <net/if_ether.h>
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#include <net80211/ieee80211_var.h>
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#include <net80211/ieee80211.h>
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#include <net80211/ieee80211_compat.h>
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#include <net80211/ieee80211_rssadapt.h>
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#ifdef IEEE80211_DEBUG
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static struct timeval lastrateadapt; /* time of last rate adaptation msg */
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static int currssadaptps = 0; /* rate-adaptation msgs this second */
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static int ieee80211_adaptrate = 4; /* rate-adaptation max msgs/sec */
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#define RSSADAPT_DO_PRINT() \
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((ieee80211_debug > 0) && \
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ppsratecheck(&lastrateadapt, &currssadaptps, ieee80211_adaptrate))
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#define RSSADAPT_PRINTF(X) \
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if (RSSADAPT_DO_PRINT()) \
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printf X
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#else
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#define RSSADAPT_DO_PRINT() (0)
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#define RSSADAPT_PRINTF(X)
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#endif
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/* RSS threshold decay. */
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u_int ieee80211_rssadapt_decay_denom = 16;
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u_int ieee80211_rssadapt_decay_old = 15;
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/* RSS threshold update. */
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u_int ieee80211_rssadapt_thresh_denom = 8;
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u_int ieee80211_rssadapt_thresh_old = 4;
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/* RSS average update. */
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u_int ieee80211_rssadapt_avgrssi_denom = 8;
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u_int ieee80211_rssadapt_avgrssi_old = 4;
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void
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ieee80211_rssadapt_updatestats(struct ieee80211_rssadapt *ra)
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{
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long interval;
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ra->ra_pktrate =
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(ra->ra_pktrate + 10 * (ra->ra_nfail + ra->ra_nok)) / 2;
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ra->ra_nfail = ra->ra_nok = 0;
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/* a node is eligible for its rate to be raised every 1/10 to 10
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* seconds, more eligible in proportion to recent packet rates.
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*/
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interval = MAX(100000, 10000000 / MAX(1, 10 * ra->ra_pktrate));
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ra->ra_raise_interval.tv_sec = interval / (1000 * 1000);
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ra->ra_raise_interval.tv_usec = interval % (1000 * 1000);
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}
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void
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ieee80211_rssadapt_input(struct ieee80211com *ic, struct ieee80211_node *ni,
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struct ieee80211_rssadapt *ra, int rssi)
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{
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int last_avg_rssi = ra->ra_avg_rssi;
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ra->ra_avg_rssi =
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(ieee80211_rssadapt_avgrssi_old * ra->ra_avg_rssi +
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ieee80211_rssadapt_avgrssi_new * (rssi << 8)) /
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ieee80211_rssadapt_avgrssi_denom;
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RSSADAPT_PRINTF(("%s: src %s rssi %d avg %d -> %d\n",
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ic->ic_if.if_xname, ether_sprintf(ni->ni_macaddr),
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rssi, last_avg_rssi, ra->ra_avg_rssi));
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}
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/*
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* Adapt the data rate to suit the conditions. When a transmitted
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* packet is dropped after IEEE80211_RSSADAPT_RETRY_LIMIT retransmissions,
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* raise the RSS threshold for transmitting packets of similar length at
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* the same data rate.
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*/
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void
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ieee80211_rssadapt_lower_rate(struct ieee80211com *ic,
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struct ieee80211_node *ni, struct ieee80211_rssadapt *ra,
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struct ieee80211_rssdesc *id)
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{
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struct ieee80211_rateset *rs = &ni->ni_rates;
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u_int16_t last_thr;
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u_int i, thridx, top;
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ra->ra_nok++;
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if (id->id_rateidx >= rs->rs_nrates) {
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RSSADAPT_PRINTF(("ieee80211_rssadapt_lower_rate: "
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"%s rate #%d > #%d out of bounds\n",
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ether_sprintf(ni->ni_macaddr), id->id_rateidx,
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rs->rs_nrates - 1));
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return;
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}
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for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
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i < IEEE80211_RSSADAPT_BKTS;
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i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
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thridx = i;
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if (id->id_len <= top)
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break;
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}
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last_thr = ra->ra_rate_thresh[thridx][id->id_rateidx];
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ra->ra_rate_thresh[thridx][id->id_rateidx] =
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(ieee80211_rssadapt_thresh_old * last_thr +
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ieee80211_rssadapt_thresh_new * (id->id_rssi << 8)) /
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ieee80211_rssadapt_thresh_denom;
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RSSADAPT_PRINTF(("%s: dst %s rssi %d threshold[%d, %d.%d] %d -> %d\n",
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ic->ic_if.if_xname, ether_sprintf(ni->ni_macaddr),
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id->id_rssi, id->id_len,
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(rs->rs_rates[id->id_rateidx] & IEEE80211_RATE_VAL) / 2,
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(rs->rs_rates[id->id_rateidx] & IEEE80211_RATE_VAL) * 5 % 10,
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last_thr, ra->ra_rate_thresh[thridx][id->id_rateidx]));
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}
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void
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ieee80211_rssadapt_raise_rate(struct ieee80211com *ic,
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struct ieee80211_rssadapt *ra, struct ieee80211_rssdesc *id)
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{
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u_int16_t (*thrs)[IEEE80211_RATE_SIZE], newthr, oldthr;
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struct ieee80211_node *ni = id->id_node;
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struct ieee80211_rateset *rs = &ni->ni_rates;
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int i, j, rate, top;
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ra->ra_nfail++;
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if (!ratecheck(&ra->ra_last_raise, &ra->ra_raise_interval))
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return;
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for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
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i < IEEE80211_RSSADAPT_BKTS;
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i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
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thrs = &ra->ra_rate_thresh[i];
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if (id->id_len <= top)
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break;
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}
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if (id->id_rateidx + 1 < rs->rs_nrates &&
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(*thrs)[id->id_rateidx + 1] > (*thrs)[id->id_rateidx]) {
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rate = (rs->rs_rates[id->id_rateidx + 1] & IEEE80211_RATE_VAL);
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RSSADAPT_PRINTF(("%s: threshold[%d, %d.%d] decay %d ",
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ic->ic_if.if_xname,
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IEEE80211_RSSADAPT_BKT0 << (IEEE80211_RSSADAPT_BKTPOWER* i),
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rate / 2, rate * 5 % 10, (*thrs)[id->id_rateidx + 1]));
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oldthr = (*thrs)[id->id_rateidx + 1];
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if ((*thrs)[id->id_rateidx] == 0)
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newthr = ra->ra_avg_rssi;
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else
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newthr = (*thrs)[id->id_rateidx];
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(*thrs)[id->id_rateidx + 1] =
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(ieee80211_rssadapt_decay_old * oldthr +
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ieee80211_rssadapt_decay_new * newthr) /
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ieee80211_rssadapt_decay_denom;
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RSSADAPT_PRINTF(("-> %d\n", (*thrs)[id->id_rateidx + 1]));
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}
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#ifdef IEEE80211_DEBUG
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if (RSSADAPT_DO_PRINT()) {
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printf("%s: dst %s thresholds\n", ic->ic_if.if_xname,
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ether_sprintf(ni->ni_macaddr));
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for (i = 0; i < IEEE80211_RSSADAPT_BKTS; i++) {
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printf("%d-byte", IEEE80211_RSSADAPT_BKT0 << (IEEE80211_RSSADAPT_BKTPOWER * i));
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for (j = 0; j < rs->rs_nrates; j++) {
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rate = (rs->rs_rates[j] & IEEE80211_RATE_VAL);
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printf(", T[%d.%d] = %d", rate / 2,
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rate * 5 % 10, ra->ra_rate_thresh[i][j]);
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}
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printf("\n");
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}
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}
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#endif /* IEEE80211_DEBUG */
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}
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