wlan: Add support for PER based roaming #2
In congested environments, it could be possible that in station
mode client gets good RSSI from AP however it's not able to
transfer data at good rates. DUT should roam to a better AP if
available, if it faces congestion in home channel.
Following changes are added for this functionality:
1. Add changes to monitor Rx and Tx rates to trigger roam scan
in case data rates are low below a preconfigured value.
2. Implement a new AP selection algorithm which will consider AP
capabilty, channel conditions and RSSI to select new bss.
Add required protocol changes for same.
Change-Id: I394c15b54ea95aa08f648f33383cb0a364278585
CRs-Fixed: 1031345
diff --git a/CORE/SME/src/csr/csrApiScan.c b/CORE/SME/src/csr/csrApiScan.c
index 79fe04a..3c5aa4b 100644
--- a/CORE/SME/src/csr/csrApiScan.c
+++ b/CORE/SME/src/csr/csrApiScan.c
@@ -2043,6 +2043,259 @@
return (ret);
}
+#ifdef WLAN_FEATURE_ROAM_SCAN_OFFLOAD
+
+/* Calculate channel weight based on other APs RSSI and count for
+ * PER based roaming */
+static tANI_U32 GetPERRoamRssiCountWeight(tANI_S32 rssi, tANI_S32 count)
+{
+ tANI_S32 rssiWeight=0;
+ tANI_S32 countWeight=0;
+ tANI_S32 rssicountWeight=0;
+
+ rssiWeight = ROAMING_RSSI_WEIGHT * (rssi - MIN_RSSI)
+ /(MAX_RSSI - MIN_RSSI);
+
+ if(rssiWeight > ROAMING_RSSI_WEIGHT)
+ rssiWeight = ROAMING_RSSI_WEIGHT;
+ else if (rssiWeight < 0)
+ rssiWeight = 0;
+
+ countWeight = ROAM_AP_COUNT_WEIGHT * (count + ROAM_MIN_COUNT)
+ /(ROAM_MAX_COUNT + ROAM_MIN_COUNT);
+
+ if(countWeight > ROAM_AP_COUNT_WEIGHT)
+ countWeight = ROAM_AP_COUNT_WEIGHT;
+
+ rssicountWeight = ROAM_MAX_WEIGHT - (rssiWeight + countWeight);
+
+ VOS_TRACE(VOS_MODULE_ID_SME, VOS_TRACE_LEVEL_INFO_HIGH,
+ FL("rssiWeight=%d, countWeight=%d, rssicountWeight=%d rssi=%d count=%d"),
+ rssiWeight, countWeight, rssicountWeight, rssi, count);
+
+ return rssicountWeight;
+}
+
+/* Calculate BSS score based on AP capabilty and channel condition
+ * for PER based roaming */
+static tANI_U32 calculateBssScore(tSirBssDescription *bssInfo,
+ tANI_S32 best_rssi, tANI_S32 ap_cnt, tANI_S32 cca)
+{
+ tANI_S32 score = 0;
+ tANI_S32 ap_load = 0;
+ tANI_S32 normalised_width = PER_ROAM_20MHZ;
+ tANI_S32 normalised_rssi;
+ tANI_S32 channel_weight;
+ if (bssInfo->rssi) {
+ /* Calculate % of rssi we are getting
+ * max = 100
+ * min = 0
+ * less than -40 = 100%
+ * -40 - -55 = 80%
+ * -55 - -65 = 60%
+ * below that = 100 - value
+ * TODO: a linear decrement function after PER_ROAM_GOOD_RSSI_WEIGHT
+ * since throughput decrements linearly after PER_ROAM_GOOD_RSSI_WEIGHT
+ **/
+ if (bssInfo->rssi >= PER_EXCELENT_RSSI)
+ normalised_rssi = PER_ROAM_EXCELLENT_RSSI_WEIGHT;
+ else if (bssInfo->rssi >= PER_GOOD_RSSI)
+ normalised_rssi = PER_ROAM_GOOD_RSSI_WEIGHT;
+ else if (bssInfo->rssi >= PER_POOR_RSSI)
+ normalised_rssi = PER_ROAM_BAD_RSSI_WEIGHT;
+ else
+ normalised_rssi = bssInfo->rssi - MIN_RSSI;
+
+ /* Calculate score part for rssi */
+ score += (normalised_rssi * RSSI_WEIGHTAGE);
+ }
+
+ if (bssInfo->HTCapsPresent) {
+ score += PER_ROAM_MAX_WEIGHT * HT_CAPABILITY_WEIGHTAGE;
+ }
+ /* VHT caps are available */
+ if (bssInfo->vhtCapsPresent) {
+ score += PER_ROAM_MAX_WEIGHT * VHT_CAP_WEIGHTAGE;
+ }
+
+ if (bssInfo->beacomformingCapable)
+ score += PER_ROAM_MAX_WEIGHT * BEAMFORMING_CAP_WEIGHTAGE;
+
+ /* Channel width 20Mhz=30, 40Mhz=70, 80Mhz=100 */
+ if (bssInfo->chanWidth == eHT_CHANNEL_WIDTH_80MHZ)
+ normalised_width = PER_ROAM_80MHZ;
+ else if (bssInfo->chanWidth == eHT_CHANNEL_WIDTH_40MHZ)
+ normalised_width = PER_ROAM_40MHZ;
+ else
+ normalised_width = PER_ROAM_20MHZ;
+ score += normalised_width * CHAN_WIDTH_WEIGHTAGE;
+
+ /* Channel Band, Channel Number */
+ if (GetRFBand(bssInfo->channelId) == SIR_BAND_5_GHZ)
+ score += PER_ROAM_MAX_WEIGHT * CHAN_BAND_WEIGHTAGE;
+
+ /* WMM emabled */
+ if (bssInfo->wmeInfoPresent)
+ score += PER_ROAM_MAX_WEIGHT * WMM_WEIGHTAGE;
+
+#if defined(FEATURE_WLAN_ESE) || defined(WLAN_FEATURE_ROAM_SCAN_OFFLOAD)
+ /* AP load Ie */
+ if (bssInfo->QBSSLoad_present) {
+ /* calculate value in % */
+ ap_load = (bssInfo->QBSS_ChanLoad * PER_ROAM_MAX_WEIGHT) / MAX_AP_LOAD;
+ }
+#endif
+ //TODO we don't have this info for current AP, need to check
+ /* if CCA consideration is off in configuration, FW will send 50% for
+ every channel which should be considered as it is */
+ if (ap_load)
+ score += (100 - ap_load) * CCA_WEIGHTAGE;
+ else
+ score += (100 - cca) * CCA_WEIGHTAGE;
+
+ channel_weight = GetPERRoamRssiCountWeight(best_rssi, ap_cnt);
+
+ score += channel_weight * OTHER_AP_WEIGHT;
+
+ VOS_TRACE(VOS_MODULE_ID_SME, VOS_TRACE_LEVEL_INFO_LOW,
+ FL("rssi=%d normalized_rssi=%d htcaps=%d vht=%d bw=%d channel=%d wmm=%d beamforming=%d ap_load=%d channel_weight=%d"),
+ bssInfo->rssi, normalised_rssi, bssInfo->HTCapsPresent,
+ bssInfo->vhtCapsPresent, bssInfo->chanWidth,
+ bssInfo->channelId, bssInfo->wmeInfoPresent,
+ bssInfo->beacomformingCapable, ap_load, channel_weight);
+ return score;
+}
+
+/* Calculate candidate AP score for PER based roaming */
+static tANI_S32 csrFindCongestionScore (tpAniSirGlobal pMac, tCsrScanResult *pBss)
+{
+ tANI_S32 score = 0;
+ tANI_S32 i;
+ tANI_S32 candidateApCnt, best_rssi, other_ap_cnt;
+ tANI_U32 current_timestamp;
+ tpCsrNeighborRoamControlInfo pNeighborRoamInfo =
+ &pMac->roam.neighborRoamInfo;
+
+ tSirBssDescription *bssInfo = &(pBss->Result.BssDescriptor);
+ pBss->congestionScore = 0;
+ for (i = 0; i < pMac->PERroamCandidatesCnt; i++)
+ if (pMac->candidateChannelInfo[i].channelNumber ==
+ pBss->Result.BssDescriptor.channelId)
+ break;
+
+ if (i == SIR_PER_ROAM_MAX_CANDIDATE_CNT) {
+ smsLog(pMac, LOGE,
+ FL("candidate chan info not found for channel %d bssid "
+ MAC_ADDRESS_STR), pBss->Result.BssDescriptor.channelId,
+ MAC_ADDR_ARRAY(pBss->Result.BssDescriptor.bssId));
+ return -1;
+ }
+
+ /* find best RSSI of other AP in this channel */
+ best_rssi = MIN_RSSI;
+ for (other_ap_cnt = 0; other_ap_cnt <
+ pMac->candidateChannelInfo[i].otherApCount; other_ap_cnt++) {
+ if (pMac->candidateChannelInfo[i].otherApRssi[other_ap_cnt] > best_rssi)
+ best_rssi = pMac->candidateChannelInfo[i].otherApRssi[other_ap_cnt];
+ }
+
+ score = calculateBssScore(bssInfo, best_rssi,
+ pMac->candidateChannelInfo[i].otherApCount,
+ pMac->candidateChannelInfo[i].channelCCA);
+ current_timestamp = jiffies_to_msecs(jiffies);
+
+ /* penalty logic */
+
+ /* In the previous list */
+ for (candidateApCnt = 0; candidateApCnt <
+ SIR_PER_ROAM_MAX_CANDIDATE_CNT; candidateApCnt++) {
+ if (sirCompareMacAddr(pMac->previousRoamApInfo[candidateApCnt].bssAddr,
+ pBss->Result.BssDescriptor.bssId) &&
+ ((current_timestamp - pMac->previousRoamApInfo[candidateApCnt].timeStamp) <
+ PENALTY_TIMEOUT)) {
+ score = (score * PENALTY_REMAINING_SCORE)/PENALTY_TOTAL_SCORE;
+ VOS_TRACE(VOS_MODULE_ID_SME, VOS_TRACE_LEVEL_INFO,
+ FL("AP BSSID " MAC_ADDRESS_STR "adding penalty(in previous list)new score %d"),
+ MAC_ADDR_ARRAY(pBss->Result.BssDescriptor.bssId),
+ score);
+ break;
+ }
+ }
+ /* preauth failed last time */
+ for (candidateApCnt = 0; candidateApCnt <
+ MAX_NUM_PREAUTH_FAIL_LIST_ADDRESS; candidateApCnt++) {
+ if (sirCompareMacAddr(pNeighborRoamInfo->FTRoamInfo.
+ preAuthFailList.macAddress[candidateApCnt],
+ pBss->Result.BssDescriptor.bssId)) {
+ score = (score * PENALTY_REMAINING_SCORE)/PENALTY_TOTAL_SCORE;
+ VOS_TRACE(VOS_MODULE_ID_SME, VOS_TRACE_LEVEL_INFO,
+ FL("AP BSSID " MAC_ADDRESS_STR "adding penalty(previously auth failed)new score %d"),
+ MAC_ADDR_ARRAY(pBss->Result.BssDescriptor.bssId),
+ score);
+ break;
+ }
+ }
+ pBss->congestionScore = score;
+
+ VOS_TRACE(VOS_MODULE_ID_SME, VOS_TRACE_LEVEL_INFO,
+ FL("AP BSSID " MAC_ADDRESS_STR " score %d channel %d"),
+ MAC_ADDR_ARRAY(pBss->Result.BssDescriptor.bssId),
+ score, pBss->Result.BssDescriptor.channelId);
+ return 0;
+}
+
+/* Calculate current AP score for PER based roaming */
+static tANI_S32 csrFindSelfCongestionScore(tpAniSirGlobal pMac,
+ tSirBssDescription *bssInfo)
+{
+ tANI_S32 i, best_rssi, other_ap_cnt;
+ tANI_S32 score = 0;
+
+ for (i = 0; i <= pMac->PERroamCandidatesCnt; i++)
+ if (pMac->candidateChannelInfo[i].channelNumber == bssInfo->channelId)
+ break;
+ if (i > pMac->PERroamCandidatesCnt) {
+ /* home channel info is not present, no need to roam */
+ VOS_TRACE(VOS_MODULE_ID_SME, VOS_TRACE_LEVEL_ERROR,
+ FL("home channel %d congestion info not present"),
+ bssInfo->channelId);
+ pMac->currentBssScore = PER_ROAM_MAX_BSS_SCORE;
+ return -1;
+ }
+
+ /* find best RSSI of other AP in this channel */
+ best_rssi = MIN_RSSI;
+ for (other_ap_cnt = 0; other_ap_cnt <
+ pMac->candidateChannelInfo[i].otherApCount; other_ap_cnt++) {
+ if (pMac->candidateChannelInfo[i].otherApRssi[other_ap_cnt] > best_rssi)
+ best_rssi = pMac->candidateChannelInfo[i].otherApRssi[other_ap_cnt];
+ }
+
+ score = calculateBssScore(bssInfo, best_rssi,
+ pMac->candidateChannelInfo[i].otherApCount,
+ pMac->candidateChannelInfo[i].channelCCA);
+ pMac->currentBssScore = score;
+ VOS_TRACE(VOS_MODULE_ID_SME, VOS_TRACE_LEVEL_INFO,
+ FL("PER Roam Current AP score %d channel %d"),
+ score, bssInfo->channelId);
+ return 0;
+}
+
+
+static tANI_BOOLEAN csrIsBetterBssInCongestion(tCsrScanResult *pBss1,
+ tCsrScanResult *pBss2)
+{
+ tANI_BOOLEAN ret;
+
+ if(CSR_IS_BETTER_PREFER_VALUE(pBss1->congestionScore,
+ pBss2->congestionScore))
+ ret = eANI_BOOLEAN_TRUE;
+ else
+ ret = eANI_BOOLEAN_FALSE;
+
+ return (ret);
+}
+#endif
//To check whther pBss1 is better than pBss2
static tANI_BOOLEAN csrIsBetterBss(tCsrScanResult *pBss1, tCsrScanResult *pBss2)
@@ -2168,7 +2421,9 @@
tDot11fBeaconIEs *pIes, *pNewIes;
tANI_BOOLEAN fMatch;
tANI_U16 i = 0;
-
+ tCsrRoamSession *pSession = CSR_GET_SESSION(pMac,
+ pMac->roam.roamSession->sessionId);
+
if(phResult)
{
*phResult = CSR_INVALID_SCANRESULT_HANDLE;
@@ -2285,7 +2540,13 @@
vos_mem_set(pRetList, sizeof(tScanResultList), 0);
csrLLOpen(pMac->hHdd, &pRetList->List);
pRetList->pCurEntry = NULL;
-
+#ifdef WLAN_FEATURE_ROAM_SCAN_OFFLOAD
+ if (pFilter && pFilter->isPERRoamScan)
+ if (pSession && pSession->pConnectBssDesc)
+ csrFindSelfCongestionScore(pMac,
+ pSession->pConnectBssDesc);
+#endif
+
csrLLLock(&pMac->scan.scanResultList);
pEntry = csrLLPeekHead( &pMac->scan.scanResultList, LL_ACCESS_NOLOCK );
while( pEntry )
@@ -2377,7 +2638,22 @@
//No need to lock pRetList because it is locally allocated and no outside can access it at this time
if(csrLLIsListEmpty(&pRetList->List, LL_ACCESS_NOLOCK))
{
- csrLLInsertTail(&pRetList->List, &pResult->Link, LL_ACCESS_NOLOCK);
+#ifdef WLAN_FEATURE_ROAM_SCAN_OFFLOAD
+ if (pFilter && pFilter->isPERRoamScan) {
+ csrFindCongestionScore(pMac, pResult);
+ if (pResult->congestionScore > pMac->currentBssScore) {
+ csrLLInsertTail(&pRetList->List, &pResult->Link,
+ LL_ACCESS_NOLOCK);
+ smsLog(pMac, LOGW,
+ FL("added one entry in LL in PER Roam list"));
+ }
+ }
+ else
+#endif
+ {
+ csrLLInsertTail(&pRetList->List, &pResult->Link,
+ LL_ACCESS_NOLOCK);
+ }
}
else
{
@@ -2389,20 +2665,48 @@
while(pTmpEntry)
{
pTmpResult = GET_BASE_ADDR( pTmpEntry, tCsrScanResult, Link );
- if(csrIsBetterBss(pResult, pTmpResult))
- {
- csrLLInsertEntry(&pRetList->List, pTmpEntry, &pResult->Link, LL_ACCESS_NOLOCK);
- //To indicate we are done
- pResult = NULL;
- break;
+#ifdef WLAN_FEATURE_ROAM_SCAN_OFFLOAD
+ if (pFilter && pFilter->isPERRoamScan) {
+ csrFindCongestionScore(pMac, pResult);
+ if(csrIsBetterBssInCongestion(pResult, pTmpResult)&&
+ (pResult->congestionScore > pMac->currentBssScore))
+ {
+ csrLLInsertEntry(&pRetList->List, pTmpEntry,
+ &pResult->Link, LL_ACCESS_NOLOCK);
+ smsLog(pMac, LOGW,
+ FL("added another entry in LL in PER Roam list"));
+ pResult = NULL;
+ break;
+ }
+ pTmpEntry = csrLLNext(&pRetList->List,
+ pTmpEntry, LL_ACCESS_NOLOCK);
}
- pTmpEntry = csrLLNext(&pRetList->List, pTmpEntry, LL_ACCESS_NOLOCK);
+ else
+#endif
+ {
+ if(csrIsBetterBss(pResult, pTmpResult))
+ {
+ csrLLInsertEntry(&pRetList->List, pTmpEntry,
+ &pResult->Link, LL_ACCESS_NOLOCK);
+ //To indicate we are done
+ pResult = NULL;
+ break;
+ }
+ pTmpEntry = csrLLNext(&pRetList->List,
+ pTmpEntry, LL_ACCESS_NOLOCK);
+ }
}
if(pResult != NULL)
- {
- //This one is not better than any one
- csrLLInsertTail(&pRetList->List, &pResult->Link, LL_ACCESS_NOLOCK);
- }
+#ifdef WLAN_FEATURE_ROAM_SCAN_OFFLOAD
+ if ((pFilter && !pFilter->isPERRoamScan) ||
+ (pFilter == NULL) ||
+ (pResult->congestionScore > pMac->currentBssScore))
+#endif
+ {
+ //This one is not better than any one
+ csrLLInsertTail(&pRetList->List,
+ &pResult->Link, LL_ACCESS_NOLOCK);
+ }
}
count++;
}
@@ -2425,6 +2729,8 @@
csrLLClose(&pRetList->List);
vos_mem_free(pRetList);
status = eHAL_STATUS_E_NULL_VALUE;
+ smsLog(pMac, LOGW,
+ FL("Nil scan results or no matching AP found"));
}
else if(phResult)
{