channel.cc

thomson_mesh_modules_Enhanced Wireless Mesh Networking for ns-2 simulator

			 rifp = (rnode->ifhead()).lh_first;
			 for(; rifp; rifp = rifp->nextnode()){
				 s.schedule(rifp, newp, propdelay);
			 }
		 }
		 delete [] affectedNodes;
	 }
	 Packet::free(p);
}


void
WirelessChannel::addNodeToList(MobileNode *mn)
{
	MobileNode *tmp;

	// create list of mobilenodes for this channel
	if (xListHead_ == NULL) {
//		fprintf(stderr, "INITIALIZE THE LIST xListHead\n"); VIVEK_NEW
		xListHead_ = mn;
		xListHead_->nextX_ = NULL;
		xListHead_->prevX_ = NULL;
	} else {
		for (tmp = xListHead_; tmp->nextX_ != NULL; tmp=tmp->nextX_);
		tmp->nextX_ = mn;
		mn->prevX_ = tmp;
		mn->nextX_ = NULL;
	}
	numNodes_++;
}

void
WirelessChannel::removeNodeFromList(MobileNode *mn) {
	
	MobileNode *tmp;
	// Find node in list
	for (tmp = xListHead_; tmp->nextX_ != NULL; tmp=tmp->nextX_) {
		if (tmp == mn) {
			if (tmp == xListHead_) {
				xListHead_ = tmp->nextX_;
				if (tmp->nextX_ != NULL)
					tmp->nextX_->prevX_ = NULL;
			} else if (tmp->nextX_ == NULL) 
				tmp->prevX_->nextX_ = NULL;
			else {
				tmp->prevX_->nextX_ = tmp->nextX_;
				tmp->nextX_->prevX_ = tmp->prevX_;
			}
			numNodes_--;
			return;
		}
	}
	fprintf(stderr, "Channel: node not found in list\n");
}

void
WirelessChannel::sortLists(void) {
	bool flag = true;
	MobileNode *m, *q;

	sorted_ = true;
	
// VIVEK_NEW	fprintf(stderr, "SORTING LISTS ...");
	/* Buble sort algorithm */
	// SORT x-list
	while(flag) {
		flag = false;
		m = xListHead_;
		while (m != NULL){
			if(m->nextX_ != NULL)
				if ( m->X() > m->nextX_->X() ){
					flag = true;
					//delete_after m;
					q = m->nextX_;
					m->nextX_ = q->nextX_;
					if (q->nextX_ != NULL)
						q->nextX_->prevX_ = m;
			    
					//insert_before m;
					q->nextX_ = m;
					q->prevX_ = m->prevX_;
					m->prevX_ = q;
					if (q->prevX_ != NULL)
						q->prevX_->nextX_ = q;

					// adjust Head of List
					if(m == xListHead_) 
						xListHead_ = m->prevX_;
				}
			m = m -> nextX_;
		}
	}
	
//VIVEK_NEW	fprintf(stderr, "DONE!\n");
}

void
WirelessChannel::updateNodesList(class MobileNode *mn, double oldX) {
	
	MobileNode* tmp;
	double X = mn->X();
	bool skipX=false;
	
	if(!sorted_) {
		sortLists();
		return;
	}
	
	/* xListHead cannot be NULL here (they are created during creation of mobilenode) */
	
	/***  DELETE ***/
	// deleting mn from x-list
	if(mn->nextX_ != NULL) {
		if(mn->prevX_ != NULL){
			if((mn->nextX_->X() >= X) && (mn->prevX_->X() <= X)) skipX = true; // the node doesn't change its position in the list
			else{
				mn->nextX_->prevX_ = mn->prevX_;
				mn->prevX_->nextX_ = mn->nextX_;
			}
		}
		
		else{
			if(mn->nextX_->X() >= X) skipX = true; // skip updating the first element
			else{
				mn->nextX_->prevX_ = NULL;
				xListHead_ = mn->nextX_;
			}
		}
	}
	
	else if(mn->prevX_ !=NULL){
		if(mn->prevX_->X() <= X) skipX = true; // skip updating the last element
		else mn->prevX_->nextX_ = NULL;
	}
	
	if ((mn->prevX_ == NULL) && (mn->nextX_ == NULL)) skipX = true; //skip updating if only one element in list
	
	/*** INSERT ***/
	//inserting mn in x-list
	if(!skipX){
		if(X > oldX){			
			for(tmp = mn; tmp->nextX_ != NULL && tmp->nextX_->X() < X; tmp = tmp->nextX_);
			//fprintf(stdout,"Scanning the element addr %d X=%0.f, next addr %d X=%0.f\n", tmp, tmp->X(), tmp->nextX_, tmp->nextX_->X());
			if(tmp->nextX_ == NULL) { 
				//fprintf(stdout, "tmp->nextX_ is NULL\n");
				tmp->nextX_ = mn;
				mn->prevX_ = tmp;
				mn->nextX_ = NULL;
			} 
			else{ 
				//fprintf(stdout, "tmp->nextX_ is not NULL, tmp->nextX_->X()=%0.f\n", tmp->nextX_->X());
				mn->prevX_ = tmp->nextX_->prevX_;
				mn->nextX_ = tmp->nextX_;
				tmp->nextX_->prevX_ = mn;  	
				tmp->nextX_ = mn;
			} 
		}
		else{
			for(tmp = mn; tmp->prevX_ != NULL && tmp->prevX_->X() > X; tmp = tmp->prevX_);
				//fprintf(stdout,"Scanning the element addr %d X=%0.f, prev addr %d X=%0.f\n", tmp, tmp->X(), tmp->prevX_, tmp->prevX_->X());
			if(tmp->prevX_ == NULL) {
				//fprintf(stdout, "tmp->prevX_ is NULL\n");
				tmp->prevX_ = mn;
				mn->nextX_ = tmp;
				mn->prevX_ = NULL;
				xListHead_ = mn;
			} 
			else{
				//fprintf(stdout, "tmp->prevX_ is not NULL, tmp->prevX_->X()=%0.f\n", tmp->prevX_->X());
				mn->nextX_ = tmp->prevX_->nextX_;
				mn->prevX_ = tmp->prevX_;
				tmp->prevX_->nextX_ = mn;  	
				tmp->prevX_ = mn;		
			}
		}
	}
}


MobileNode **
WirelessChannel::getAffectedNodes(MobileNode *mn, double radius,
				  int *numAffectedNodes)
{
	double xmin, xmax, ymin, ymax;
	int n = 0;
	MobileNode *tmp, **list, **tmpList;

	if (xListHead_ == NULL) {
		*numAffectedNodes=-1;
		fprintf(stderr, "xListHead_ is NULL when trying to send!!!\n");
		return NULL;
	}
	
	xmin = mn->X() - radius;
	xmax = mn->X() + radius;
	ymin = mn->Y() - radius;
	ymax = mn->Y() + radius;
	
	// First allocate as much as possibly needed
	tmpList = new MobileNode*[numNodes_];
	
	for(tmp = xListHead_; tmp != NULL; tmp = tmp->nextX_) tmpList[n++] = tmp;
	for(int i = 0; i < n; ++i)
		if(tmpList[i]->speed()!=0.0 && (Scheduler::instance().clock() -
						tmpList[i]->getUpdateTime()) > XLIST_POSITION_UPDATE_INTERVAL )
			tmpList[i]->update_position();
	n=0;
	
	for(tmp = mn; tmp != NULL && tmp->X() >= xmin; tmp=tmp->prevX_)
		if(tmp->Y() >= ymin && tmp->Y() <= ymax){
			tmpList[n++] = tmp;
		}
	for(tmp = mn->nextX_; tmp != NULL && tmp->X() <= xmax; tmp=tmp->nextX_){
		if(tmp->Y() >= ymin && tmp->Y() <= ymax){
			tmpList[n++] = tmp;
		}
	}
	
	list = new MobileNode*[n];
	memcpy(list, tmpList, n * sizeof(MobileNode *));
	delete [] tmpList;
         
	*numAffectedNodes = n;
	return list;
}
 


/* Only to be used with mobile nodes (WirelessPhy).
 * NS-2 at its current state support only a flat (non 3D) movement of nodes,
 * so we assume antenna heights do not change for the dureation of
 * a simulation.
 * Another assumption - all nodes have the same wireless interface, so that
 * the maximum distance, corresponding to CST (at max transmission power 
 * level) stays the same for all nodes.
 */
void
WirelessChannel::calcHighestAntennaZ(Phy *tifp)
{
       double highestZ = 0;
       Phy *n;
 
       for(n = ifhead_.lh_first; n; n = n->nextchnl()) {
                   if(((WirelessPhy *)n)->getAntennaZ() > highestZ)
                               highestZ = ((WirelessPhy *)n)->getAntennaZ();
       }
 
       highestAntennaZ_ = highestZ;

       WirelessPhy *wifp = (WirelessPhy *)tifp;
       distCST_ = wifp->getDist(wifp->getCSThresh(), wifp->getPt(), 1.0, 1.0,
				highestZ , highestZ, wifp->getL(),
				wifp->getLambda());       
}

	
double
WirelessChannel::get_pdelay(Node* tnode, Node* rnode)
{
	// Scheduler	&s = Scheduler::instance();
	MobileNode* tmnode = (MobileNode*)tnode;
	MobileNode* rmnode = (MobileNode*)rnode;
	double propdelay = 0;
	
	propdelay = tmnode->propdelay(rmnode);

	assert(propdelay >= 0.0);
	if (propdelay == 0.0) {
		/* if the propdelay is 0 b/c two nodes are on top of 
		   each other, move them slightly apart -dam 7/28/98 */
		propdelay = 2 * DBL_EPSILON;
		//printf ("propdelay 0: %d->%d at %f\n",
		//	tmnode->address(), rmnode->address(), s.clock());
	}
	return propdelay;
}

	

// send():
//  The packet occupies the channel for the transmission time, txtime
//  If collision occur (>1 pkts overlap), corrupt all pkts involved
//	by setting the error bit or discard them

// int Channel::send(Packet* p, Phy *tifp)
// {
// 	// without collision, return 0
// 	Scheduler& s = Scheduler::instance();
// 	double now = s.clock();

// 	// busy = time when the channel are still busy with earlier tx
// 	double busy = max(txstop_, cwstop_);

// 	// txstop = when the channel is no longer busy from this tx
// 	txstop_ = max(busy, now + txtime);

// 	// now < busy => collision
// 	//	mark the pkt error bit, EF_COLLISION
// 	//	drop if there is a drop target, drop_
// 	if (now < busy) {
// 		// if still transmit earlier packet, pkt_, then corrupt it
// 		if (pkt_ && pkt_->time_ > now) {
// 			hdr_cmn::access(pkt_)->error() |= EF_COLLISION;
// 			if (drop_) {
// 				s.cancel(pkt_);
// 				drop(pkt_);
// 				pkt_ = 0;
// 			}
// 		}

// 		// corrupts the current packet p, and drop if drop_ exists
// 		hdr_cmn::access(p)->error() |= EF_COLLISION;
// 		if (drop_) {
// 			drop(p);
// 			return 1;
// 		}
// 	}

// 	// if p was not dropped, call recv() or hand it to trace_ if present
// 	pkt_ = p;
// 	trace_ ? trace_->recv(p, 0) : recv(p, 0);
// 	return 0;
// }


// contention():
//  The MAC calls this Channel::contention() to enter contention period
//  It determines when the contention window is over, cwstop_,
//	and schedule a callback to the MAC for the actual send()

// void Channel::contention(Packet* p, Handler* h)
// {
// 	Scheduler& s = Scheduler::instance();
// 	double now = s.clock();
// 	if (now > cwstop_) {
// 		cwstop_ = now + delay_;
// 		numtx_ = 0;
// 	}
// 	numtx_++;
// 	s.schedule(h, p, cwstop_ - now);
// }


// jam():
//  Jam the channel for a period txtime
//  Some MAC protocols use this to let other MAC detect collisions

// int Channel::jam(double txtime)
// {
// 	// without collision, return 0
// 	double now = Scheduler::instance().clock();
// 	if (txstop_ > now) {
// 		txstop_ = max(txstop_, now + txtime);
// 		return 1;
// 	}
// 	txstop_ = now + txtime;
// 	return (now < cwstop_);
// }


// int DuplexChannel::send(Packet* p, double txtime)
// {
// 	double now = Scheduler::instance().clock();
// 	txstop_ = now + txtime;
// 	trace_ ? trace_->recv(p, 0) : recv(p, 0);
// 	return 0;
// }


// void DuplexChannel::contention(Packet* p, Handler* h)
// {
// 	Scheduler::instance().schedule(h, p, delay_);
// 	numtx_ = 1;
// }