參考：http://godpk.blogspot.com/2007_04_01_archive.html

WimaxCtrlAgent =

NIST供16e掃描/換手

NIST除了提供IEEE 802.16d的功能外

也提供IEEE 802.16e通訊協定的掃描與換手

當SS想要尋找鄰近可連線的基地台時

該SS便會傳送掃描請求(Scan Request)給目前的基地台

當基地台收到掃描請求時

基地台會分配掃描間隔(Scanning Interval)，

如此基地台與SS就可暫時停止封包傳輸以避免封包遺失。

NIST模組中的WiMAXCtrl代理人(Agent)類別便是用來負責分配掃描間隔以與基地台同步，

同時也傳送鄰居通告(Neighbor Advertisement)給SS。

備註：

My Documents/ns2package/ns-2.29/wimax/scheduling/wimaxctrlagent.h

My Documents/ns2package/ns-2.29/wimax/scheduling/wimaxctrlagent.cc

My Documents/ns2package/ns-2.29/wimax/mac802_16timer.h

My Documents/ns2package/ns-2.29/wimax/mac802_16timer.cc

WiMAX module of NIST ：

其service flow未開發完成(但有handoff)

ps.l2handover.tcl??

NIST Handover 重要function ：

Define old link(ss & old BS) and new link(ss & new BS)

void Mac::send_link_handover_imminent (int macTerminal, int oldPoA, int macPoA){ if (mih_ && ((subscribedEventList_ >> MIH_LINK_HANDOVER_IMMINENT)& 0x1) ) {

link_handover_imminent_t *e = (link_handover_imminent_t*) malloc (sizeof (link_handover_imminent_t)); e->linkIdentifier.type = linkType_; e->linkIdentifier.macMobileTerminal = macTerminal; e->linkIdentifier.macPoA = oldPoA; e->newLinkIdentifier.type = linkType_; e->newLinkIdentifier.macMobileTerminal = macTerminal; e->newLinkIdentifier.macPoA = macPoA; e->macOldAccessRouter = oldPoA; e->macNewAccessRouter = macPoA; mih_->recv_event (MIH_LINK_HANDOVER_IMMINENT, e); } //else we don't need to do anything}

設定 SS 跟BS連接：

$init_node($i) base-station [AddrParams addr2id [$bstationWIMAX($i) node-addr]] ;

發生Handoff 之前的 函數執行順序 ：

process_link_going_down

process_link_down

NIST Scan 流程 ：

1. SSscheduler::pause_scanning ()

2. Mac::send_scan_result (void *res, int size)

3. MIHAgent::process_scan_response (Mac *mac, void *rsp, int size)

3.1 MIHScan::process_scan_response (int macAddr, void *rsp, int size)

4. Handover1::process_scan_conf (struct mih_scan_rsp *rsp)

封包在模組之間的流程 ：

mac-802.16.cc -> phy.cc -> wirlessphy.cc->channel.cc-> channel.cc (WirelessChannel::sendUp(Packet* p, Phy *tifp)) ->

NS2 trace format：

For example：

s -t 5.144001358 -Hs 1 -Hd -2

-Ni 1 -Nx 50.00 -Ny 50.00 -Nz 0.00

-Ne -1.000000

-Nl MAC

-Nw --- -Ma 0 -Md 0 -Ms 0 -Mt 0

在 5.144001358, node 1 傳送給 node 2

node 1 的 x座標50 ,y座標50,z座標 0 ,

Node Energy Level = -1

Network trace Level = MAC

Drop Reason = null

BS 發送 鄰近BS相關資訊 :

At 0.504001 in BS 0 send_nbr_adv (nb_neighbor=1)

BS0 送出鄰近BS資訊, nb_neighbor=1 代表有一個鄰近BS

ps. 找send_Beacon_frame??

or 自己建造？

NIST 建立packet 的一些動作 ：

mac_->getPacket ();

struct hdr_cmn *ch = HDR_CMN(rep);

rep->allocdata (sizeof (struct mac802_16_rng_rsp_frame));

mac802_16_rng_rsp_frame *frame = (mac802_16_rng_rsp_frame*) rep->accessdata();

frame->type = MAC_RNG_RSP;

frame->uc_id = ulsubframe->getChannelID();

frame->rng_status = RNG_SUCCESS;

frame->ss_mac_address = req->ss_mac_address;

frame->basic_cid = basic->get_cid();

frame->primary_cid = primary->get_cid();

ch->size() = RNG_RSP_SIZE;

Burst *b = map_->getDlSubframe()->getPdu ()->getBurst (0);

double txtime = mac_->getPhy()->getTrxTime (ch->size(),map_->getDlSubframe()->getProfile (b->getIUC())->getEncoding());

ch->txtime() = txtime;

mac_->getCManager()->get_connection (BROADCAST_CID, false)->enqueue (rep);

<h3>CreateAllocationStartTime(int NodeID) :</h3>

AllocationStartTime_link* Mac802_16::CreateAllocationStartTime(int NodeID)

{

AllocationStartTime_link *tmp = new AllocationStartTime_link;

tmp->NodeID = NodeID;

tmp->AllocationStartTime = 0;

if(!AllocationStartTime_link_head) {

AllocationStartTime_link_head = AllocationStartTime_link_tail = tmp;

tmp->next = NULL;

}

else {

AllocationStartTime_link_tail->next = tmp;

AllocationStartTime_link_tail = tmp;

tmp->next = NULL;

}

return tmp;

}