Ieee80211Mac Class Reference

#include <Ieee80211Mac.h>

Inheritance diagram for Ieee80211Mac:

List of all members.

Classes
struct	Ieee80211ASFTuple
Public Member Functions
Construction functions
	Ieee80211Mac ()
virtual	~Ieee80211Mac ()
Protected Member Functions
virtual Ieee80211Frame *	setBasicBitrate (Ieee80211Frame *frame)
	Attaches a PhyControlInfo to the frame which will cause it to be sent at basicBitrate not bitrate (e.g. 2Mbps instead of 11Mbps). Used with ACK, CTS, RTS.
Initialization functions
virtual int	numInitStages () const
	Initialization of the module and its variables.
virtual void	initialize (int)
	Initialization of the module and some variables.
virtual void	registerInterface ()
virtual void	initializeQueueModule ()
Message handing functions
Functions called from other classes to notify about state changes and to handle messages.
virtual void	receiveChangeNotification (int category, const cPolymorphic *details)
	Called by the NotificationBoard whenever a change occurs we're interested in.
virtual void	handleCommand (cMessage *msg)
	Handle commands (msg kind+control info) coming from upper layers.
virtual void	handleSelfMsg (cMessage *msg)
	Handle timer self messages.
virtual void	handleUpperMsg (cPacket *msg)
	Handle messages from upper layer.
virtual void	handleLowerMsg (cPacket *msg)
	Handle messages from lower (physical) layer.
virtual void	handleWithFSM (cMessage *msg)
	Handle all kinds of messages and notifications with the state machine.
Timing functions
Calculate various timings based on transmission rate and physical layer charactersitics.
virtual simtime_t	getSIFS ()
virtual simtime_t	getSlotTime ()
virtual simtime_t	getDIFS ()
virtual simtime_t	getEIFS ()
virtual simtime_t	getPIFS ()
virtual simtime_t	computeBackoffPeriod (Ieee80211Frame *msg, int r)
Timer functions
These functions have the side effect of starting the corresponding timers.
virtual void	scheduleSIFSPeriod (Ieee80211Frame *frame)
virtual void	scheduleDIFSPeriod ()
virtual void	cancelDIFSPeriod ()
virtual void	scheduleDataTimeoutPeriod (Ieee80211DataOrMgmtFrame *frame)
virtual void	scheduleBroadcastTimeoutPeriod (Ieee80211DataOrMgmtFrame *frame)
virtual void	cancelTimeoutPeriod ()
virtual void	scheduleCTSTimeoutPeriod ()
virtual void	scheduleReservePeriod (Ieee80211Frame *frame)
	Schedule network allocation period according to 9.2.5.4.
virtual void	invalidateBackoffPeriod ()
	Generates a new backoff period based on the contention window.
virtual bool	isInvalidBackoffPeriod ()
virtual void	generateBackoffPeriod ()
virtual void	decreaseBackoffPeriod ()
virtual void	scheduleBackoffPeriod ()
virtual void	cancelBackoffPeriod ()
Frame transmission functions
virtual void	sendACKFrameOnEndSIFS ()
virtual void	sendACKFrame (Ieee80211DataOrMgmtFrame *frame)
virtual void	sendRTSFrame (Ieee80211DataOrMgmtFrame *frameToSend)
virtual void	sendCTSFrameOnEndSIFS ()
virtual void	sendCTSFrame (Ieee80211RTSFrame *rtsFrame)
virtual void	sendDataFrameOnEndSIFS (Ieee80211DataOrMgmtFrame *frameToSend)
virtual void	sendDataFrame (Ieee80211DataOrMgmtFrame *frameToSend)
virtual void	sendBroadcastFrame (Ieee80211DataOrMgmtFrame *frameToSend)
Frame builder functions
virtual Ieee80211DataOrMgmtFrame *	buildDataFrame (Ieee80211DataOrMgmtFrame *frameToSend)
virtual Ieee80211ACKFrame *	buildACKFrame (Ieee80211DataOrMgmtFrame *frameToACK)
virtual Ieee80211RTSFrame *	buildRTSFrame (Ieee80211DataOrMgmtFrame *frameToSend)
virtual Ieee80211CTSFrame *	buildCTSFrame (Ieee80211RTSFrame *rtsFrame)
virtual Ieee80211DataOrMgmtFrame *	buildBroadcastFrame (Ieee80211DataOrMgmtFrame *frameToSend)
Utility functions
virtual void	finishCurrentTransmission ()
virtual void	giveUpCurrentTransmission ()
virtual void	retryCurrentTransmission ()
virtual void	sendDownPendingRadioConfigMsg ()
	Send down the change channel message to the physical layer if there is any.
virtual void	setMode (Mode mode)
	Change the current MAC operation mode.
virtual Ieee80211DataOrMgmtFrame *	getCurrentTransmission ()
	Returns the current frame being transmitted.
virtual void	resetStateVariables ()
	Reset backoff, backoffPeriod and retryCounter for IDLE state.
virtual bool	isMediumStateChange (cMessage *msg)
	Used by the state machine to identify medium state change events. This message is currently optimized away and not sent through the kernel.
virtual bool	isMediumFree ()
	Tells if the medium is free according to the physical and virtual carrier sense algorithm.
virtual bool	isBroadcast (Ieee80211Frame *msg)
	Returns true if message is a broadcast message.
virtual bool	isForUs (Ieee80211Frame *msg)
	Returns true if message destination address is ours.
virtual bool	isDataOrMgmtFrame (Ieee80211Frame *frame)
	Checks if the frame is a data or management frame.
virtual Ieee80211Frame *	getFrameReceivedBeforeSIFS ()
	Returns the last frame received before the SIFS period.
virtual void	popTransmissionQueue ()
	Deletes frame at the front of queue.
virtual double	computeFrameDuration (Ieee80211Frame *msg)
	Computes the duration (in seconds) of the transmission of a frame over the physical channel. 'bits' should be the total length of the MAC frame in bits, but excluding the physical layer framing (preamble etc.)
virtual double	computeFrameDuration (int bits, double bitrate)
virtual void	logState ()
	Logs all state information.
const char *	modeName (int mode)
	Produce a readable name of the given MAC operation mode.
Protected Attributes
Timer messages
cMessage *	endSIFS
cMessage *	endDIFS
cMessage *	endBackoff
cMessage *	endTimeout
cMessage *	endReserve
cMessage *	mediumStateChange
Statistics
long	numRetry
long	numSentWithoutRetry
long	numGivenUp
long	numCollision
long	numSent
long	numReceived
long	numSentBroadcast
long	numReceivedBroadcast
cOutVector	stateVector
cOutVector	radioStateVector
Private Types
typedef std::list < Ieee80211DataOrMgmtFrame * >	Ieee80211DataOrMgmtFrameList
typedef std::list < Ieee80211ASFTuple * >	Ieee80211ASFTupleList
Configuration parameters
These are filled in during the initialization phase and not supposed to change afterwards.
MACAddress	address
double	bitrate
double	basicBitrate
int	maxQueueSize
int	rtsThreshold
int	transmissionLimit
int	cwMinData
int	cwMinBroadcast
static const int	fragmentationThreshold = 2346
Ieee80211Mac state variables
Various state information checked and modified according to the state machine.
enum	State {   IDLE, DEFER, WAITDIFS, BACKOFF,   WAITACK, WAITBROADCAST, WAITCTS, WAITSIFS,   RECEIVE }
enum	Mode { DCF, PCF }
cFSM	fsm
Mode	mode
int	sequenceNumber
bool	lastReceiveFailed
bool	backoff
bool	nav
simtime_t	backoffPeriod
int	retryCounter
RadioState::State	radioState
Ieee80211DataOrMgmtFrameList	transmissionQueue
Ieee80211ASFTupleList	asfTuplesList
IPassiveQueue *	queueModule
cMessage *	pendingRadioConfigMsg

---

Detailed Description

IEEE 802.11b Media Access Control Layer.

Various comments in the code refer to the Wireless LAN Medium Access Control (MAC) and Physical Layer(PHY) Specifications ANSI/IEEE Std 802.11, 1999 Edition (R2003)

For more info, see the NED file.

TODO: support fragmentation TODO: PCF mode TODO: CF period TODO: pass radio power to upper layer TODO: transmission complete notification to upper layer TODO: STA TCF timer syncronization, see Chapter 11 pp 123

Parts of the implementation have been taken over from the Mobility Framework's Mac80211 module.

Definition at line 54 of file Ieee80211Mac.h.

---

Member Typedef Documentation

typedef std::list<Ieee80211ASFTuple*> Ieee80211Mac::Ieee80211ASFTupleList [private]

Definition at line 68 of file Ieee80211Mac.h.

typedef std::list<Ieee80211DataOrMgmtFrame*> Ieee80211Mac::Ieee80211DataOrMgmtFrameList [private]

Definition at line 56 of file Ieee80211Mac.h.

---

Member Enumeration Documentation

enum Ieee80211Mac::Mode

80211 MAC operation modes

Enumerator:

DCF	Distributed Coordination Function.
PCF	Point Coordination Function.

Definition at line 141 of file Ieee80211Mac.h.

              {
        DCF,  
        PCF,  
    };

enum Ieee80211Mac::State

the 80211 MAC state machine

Enumerator:

IDLE
DEFER
WAITDIFS
BACKOFF
WAITACK
WAITBROADCAST
WAITCTS
WAITSIFS
RECEIVE

Definition at line 125 of file Ieee80211Mac.h.

               {
        IDLE,
        DEFER,
        WAITDIFS,
        BACKOFF,
        WAITACK,
        WAITBROADCAST,
        WAITCTS,
        WAITSIFS,
        RECEIVE,
    };

---

Constructor & Destructor Documentation

Ieee80211Mac::Ieee80211Mac

(

)

Definition at line 49 of file Ieee80211Mac.cc.

{
    endSIFS = NULL;
    endDIFS = NULL;
    endBackoff = NULL;
    endTimeout = NULL;
    endReserve = NULL;
    mediumStateChange = NULL;
    pendingRadioConfigMsg = NULL;
}

Ieee80211Mac::~Ieee80211Mac

(

)

[virtual]

Definition at line 60 of file Ieee80211Mac.cc.

{
    cancelAndDelete(endSIFS);
    cancelAndDelete(endDIFS);
    cancelAndDelete(endBackoff);
    cancelAndDelete(endTimeout);
    cancelAndDelete(endReserve);
    cancelAndDelete(mediumStateChange);

    if (pendingRadioConfigMsg)
        delete pendingRadioConfigMsg;
}

---

Member Function Documentation

Ieee80211ACKFrame * Ieee80211Mac::buildACKFrame

(

Ieee80211DataOrMgmtFrame *

frameToACK

)

[protected, virtual]

Definition at line 845 of file Ieee80211Mac.cc.

Referenced by sendACKFrame().

{
    Ieee80211ACKFrame *frame = new Ieee80211ACKFrame("wlan-ack");
    frame->setReceiverAddress(frameToACK->getTransmitterAddress());

    if (!frameToACK->getMoreFragments())
        frame->setDuration(0);
    else
        frame->setDuration(frameToACK->getDuration() - getSIFS() - computeFrameDuration(LENGTH_ACK, basicBitrate));

    return frame;
}

Ieee80211DataOrMgmtFrame * Ieee80211Mac::buildBroadcastFrame

(

Ieee80211DataOrMgmtFrame *

frameToSend

)

[protected, virtual]

Definition at line 879 of file Ieee80211Mac.cc.

Referenced by sendBroadcastFrame().

{
    Ieee80211DataOrMgmtFrame *frame = (Ieee80211DataOrMgmtFrame *)frameToSend->dup();
    frame->setDuration(0);
    return frame;
}

Ieee80211CTSFrame * Ieee80211Mac::buildCTSFrame

(

Ieee80211RTSFrame *

rtsFrame

)

[protected, virtual]

Definition at line 870 of file Ieee80211Mac.cc.

Referenced by sendCTSFrame().

{
    Ieee80211CTSFrame *frame = new Ieee80211CTSFrame("wlan-cts");
    frame->setReceiverAddress(rtsFrame->getTransmitterAddress());
    frame->setDuration(rtsFrame->getDuration() - getSIFS() - computeFrameDuration(LENGTH_CTS, basicBitrate));

    return frame;
}

Ieee80211DataOrMgmtFrame * Ieee80211Mac::buildDataFrame

(

Ieee80211DataOrMgmtFrame *

frameToSend

)

[protected, virtual]

Definition at line 830 of file Ieee80211Mac.cc.

Referenced by sendDataFrame().

{
    Ieee80211DataOrMgmtFrame *frame = (Ieee80211DataOrMgmtFrame *)frameToSend->dup();

    if (isBroadcast(frameToSend))
        frame->setDuration(0);
    else if (!frameToSend->getMoreFragments())
        frame->setDuration(getSIFS() + computeFrameDuration(LENGTH_ACK, basicBitrate));
    else
        // FIXME: shouldn't we use the next frame to be sent?
        frame->setDuration(3 * getSIFS() + 2 * computeFrameDuration(LENGTH_ACK, basicBitrate) + computeFrameDuration(frameToSend));

    return frame;
}

Ieee80211RTSFrame * Ieee80211Mac::buildRTSFrame

(

Ieee80211DataOrMgmtFrame *

frameToSend

)

[protected, virtual]

Definition at line 858 of file Ieee80211Mac.cc.

Referenced by sendRTSFrame().

{
    Ieee80211RTSFrame *frame = new Ieee80211RTSFrame("wlan-rts");
    frame->setTransmitterAddress(address);
    frame->setReceiverAddress(frameToSend->getReceiverAddress());
    frame->setDuration(3 * getSIFS() + computeFrameDuration(LENGTH_CTS, basicBitrate) +
                       computeFrameDuration(frameToSend) +
                       computeFrameDuration(LENGTH_ACK, basicBitrate));

    return frame;
}

void Ieee80211Mac::cancelBackoffPeriod

(

)

[protected, virtual]

Definition at line 764 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    EV << "cancelling Backoff period\n";
    cancelEvent(endBackoff);
}

void Ieee80211Mac::cancelDIFSPeriod

(

)

[protected, virtual]

Definition at line 672 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    EV << "cancelling DIFS period\n";
    cancelEvent(endDIFS);
}

void Ieee80211Mac::cancelTimeoutPeriod

(

)

[protected, virtual]

Definition at line 690 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    EV << "cancelling timeout period\n";
    cancelEvent(endTimeout);
}

simtime_t Ieee80211Mac::computeBackoffPeriod	(	Ieee80211Frame *	msg,
		int	r
	)		[protected, virtual]

Definition at line 623 of file Ieee80211Mac.cc.

Referenced by generateBackoffPeriod().

{
    int cw;

    EV << "generating backoff slot number for retry: " << r << endl;

    if (isBroadcast(msg))
        cw = cwMinBroadcast;
    else
    {
        ASSERT(0 <= r && r < transmissionLimit);

        cw = (cwMinData + 1) * (1 << r) - 1;

        if (cw > CW_MAX)
            cw = CW_MAX;
    }

    int c = intrand(cw + 1);

    EV << "generated backoff slot number: " << c << " , cw: " << cw << endl;

    return ((double)c) * getSlotTime();
}

double Ieee80211Mac::computeFrameDuration

(

Ieee80211Frame *

msg

)

[protected, virtual]

Computes the duration (in seconds) of the transmission of a frame over the physical channel. 'bits' should be the total length of the MAC frame in bits, but excluding the physical layer framing (preamble etc.)

Definition at line 1002 of file Ieee80211Mac.cc.

Referenced by buildACKFrame(), buildCTSFrame(), buildDataFrame(), buildRTSFrame(), scheduleBroadcastTimeoutPeriod(), scheduleCTSTimeoutPeriod(), and scheduleDataTimeoutPeriod().

{
    return computeFrameDuration(msg->getBitLength(), bitrate);
}

double Ieee80211Mac::computeFrameDuration	(	int	bits,
		double	bitrate
	)		[protected, virtual]

Definition at line 1007 of file Ieee80211Mac.cc.

{
    return bits / bitrate + PHY_HEADER_LENGTH / BITRATE_HEADER;
}

void Ieee80211Mac::decreaseBackoffPeriod

(

)

[protected, virtual]

Definition at line 749 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    // see spec 9.2.5.2
    simtime_t elapsedBackoffTime = simTime() - endBackoff->getSendingTime();
    backoffPeriod -= ((int)(elapsedBackoffTime / getSlotTime())) * getSlotTime();
    ASSERT(backoffPeriod >= 0);
    EV << "backoff period decreased to " << backoffPeriod << endl;
}

void Ieee80211Mac::finishCurrentTransmission

(

)

[protected, virtual]

Definition at line 898 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    popTransmissionQueue();
    resetStateVariables();
}

void Ieee80211Mac::generateBackoffPeriod

(

)

[protected, virtual]

Definition at line 742 of file Ieee80211Mac.cc.

Referenced by handleWithFSM(), and retryCurrentTransmission().

{
    backoffPeriod = computeBackoffPeriod(getCurrentTransmission(), retryCounter);
    ASSERT(backoffPeriod >= 0);
    EV << "backoff period set to " << backoffPeriod << endl;
}

Ieee80211DataOrMgmtFrame * Ieee80211Mac::getCurrentTransmission

(

)

[protected, virtual]

Returns the current frame being transmitted.

Definition at line 921 of file Ieee80211Mac.cc.

Referenced by generateBackoffPeriod(), handleWithFSM(), resetStateVariables(), and retryCurrentTransmission().

{
    return (Ieee80211DataOrMgmtFrame *)transmissionQueue.front();
}

simtime_t Ieee80211Mac::getDIFS

(

)

[protected, virtual]

Definition at line 612 of file Ieee80211Mac.cc.

Referenced by getEIFS(), and scheduleDIFSPeriod().

{
    return getSIFS() + 2 * getSlotTime();
}

simtime_t Ieee80211Mac::getEIFS

(

)

[protected, virtual]

Definition at line 617 of file Ieee80211Mac.cc.

Referenced by scheduleDIFSPeriod().

{
// FIXME:   return getSIFS() + getDIFS() + (8 * ACKSize + aPreambleLength + aPLCPHeaderLength) / lowestDatarate;
    return getSIFS() + getDIFS() + (8 * LENGTH_ACK + PHY_HEADER_LENGTH) / 1E+6;
}

Ieee80211Frame * Ieee80211Mac::getFrameReceivedBeforeSIFS

(

)

[protected, virtual]

Returns the last frame received before the SIFS period.

Definition at line 982 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    return (Ieee80211Frame *)endSIFS->getContextPointer();
}

simtime_t Ieee80211Mac::getPIFS

(

)

[protected, virtual]

Definition at line 607 of file Ieee80211Mac.cc.

{
    return getSIFS() + getSlotTime();
}

simtime_t Ieee80211Mac::getSIFS

(

)

[protected, virtual]

Definition at line 595 of file Ieee80211Mac.cc.

Referenced by buildACKFrame(), buildCTSFrame(), buildDataFrame(), buildRTSFrame(), getDIFS(), getEIFS(), getPIFS(), scheduleCTSTimeoutPeriod(), scheduleDataTimeoutPeriod(), and scheduleSIFSPeriod().

{
// TODO:   return aRxRFDelay() + aRxPLCPDelay() + aMACProcessingDelay() + aRxTxTurnaroundTime();
    return SIFS;
}

simtime_t Ieee80211Mac::getSlotTime

(

)

[protected, virtual]

Definition at line 601 of file Ieee80211Mac.cc.

Referenced by computeBackoffPeriod(), decreaseBackoffPeriod(), getDIFS(), and getPIFS().

{
// TODO:   return aCCATime() + aRxTxTurnaroundTime + aAirPropagationTime() + aMACProcessingDelay();
    return ST;
}

void Ieee80211Mac::giveUpCurrentTransmission

(

)

[protected, virtual]

Definition at line 904 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    popTransmissionQueue();
    resetStateVariables();
    numGivenUp++;
}

void Ieee80211Mac::handleCommand

(

cMessage *

msg

)

[protected, virtual]

Handle commands (msg kind+control info) coming from upper layers.

Implements WirelessMacBase.

Definition at line 266 of file Ieee80211Mac.cc.

{
    if (msg->getKind()==PHY_C_CONFIGURERADIO)
    {
        EV << "Passing on command " << msg->getName() << " to physical layer\n";
        if (pendingRadioConfigMsg != NULL)
        {
            // merge contents of the old command into the new one, then delete it
            PhyControlInfo *pOld = check_and_cast<PhyControlInfo *>(pendingRadioConfigMsg->getControlInfo());
            PhyControlInfo *pNew = check_and_cast<PhyControlInfo *>(msg->getControlInfo());
            if (pNew->getChannelNumber()==-1 && pOld->getChannelNumber()!=-1)
                pNew->setChannelNumber(pOld->getChannelNumber());
            if (pNew->getBitrate()==-1 && pOld->getBitrate()!=-1)
                pNew->setBitrate(pOld->getBitrate());
            delete pendingRadioConfigMsg;
            pendingRadioConfigMsg = NULL;
        }

        if (fsm.getState() == IDLE || fsm.getState() == DEFER || fsm.getState() == BACKOFF)
        {
            EV << "Sending it down immediately\n";
            sendDown(msg);
        }
        else
        {
            EV << "Delaying " << msg->getName() << " until next IDLE or DEFER state\n";
            pendingRadioConfigMsg = msg;
        }
    }
    else
    {
        error("Unrecognized command from mgmt layer: (%s)%s msgkind=%d", msg->getClassName(), msg->getName(), msg->getKind());
    }
}

void Ieee80211Mac::handleLowerMsg

(

cPacket *

msg

)

[protected, virtual]

Handle messages from lower (physical) layer.

Implements WirelessMacBase.

Definition at line 301 of file Ieee80211Mac.cc.

{
    EV << "received message from lower layer: " << msg << endl;

    Ieee80211Frame *frame = dynamic_cast<Ieee80211Frame *>(msg);
    if (!frame)
        error("message from physical layer (%s)%s is not a subclass of Ieee80211Frame",
              msg->getClassName(), msg->getName());

    EV << "Self address: " << address
       << ", receiver address: " << frame->getReceiverAddress()
       << ", received frame is for us: " << isForUs(frame) << endl;

    Ieee80211TwoAddressFrame *twoAddressFrame = dynamic_cast<Ieee80211TwoAddressFrame *>(msg);
    ASSERT(!twoAddressFrame || twoAddressFrame->getTransmitterAddress() != address);

    handleWithFSM(msg);

    // if we are the owner then we did not send this message up
    if (msg->getOwner() == this)
        delete msg;
}

void Ieee80211Mac::handleSelfMsg

(

cMessage *

msg

)

[protected, virtual]

Handle timer self messages.

Implements WirelessMacBase.

Definition at line 227 of file Ieee80211Mac.cc.

{
    EV << "received self message: " << msg << endl;

    if (msg == endReserve)
        nav = false;

    handleWithFSM(msg);
}

void Ieee80211Mac::handleUpperMsg

(

cPacket *

msg

)

[protected, virtual]

Handle messages from upper layer.

Implements WirelessMacBase.

Definition at line 237 of file Ieee80211Mac.cc.

{
    // check for queue overflow
    if (maxQueueSize && (int)transmissionQueue.size() == maxQueueSize)
    {
        EV << "message " << msg << " received from higher layer but MAC queue is full, dropping message\n";
        delete msg;
        return;
    }

    // must be a Ieee80211DataOrMgmtFrame, within the max size because we don't support fragmentation
    Ieee80211DataOrMgmtFrame *frame = check_and_cast<Ieee80211DataOrMgmtFrame *>(msg);
    if (frame->getByteLength() > fragmentationThreshold)
        error("message from higher layer (%s)%s is too long for 802.11b, %d bytes (fragmentation is not supported yet)",
              msg->getClassName(), msg->getName(), (int)(msg->getByteLength()));
    EV << "frame " << frame << " received from higher layer, receiver = " << frame->getReceiverAddress() << endl;

    ASSERT(!frame->getReceiverAddress().isUnspecified());

    // fill in missing fields (receiver address, seq number), and insert into the queue
    frame->setTransmitterAddress(address);
    frame->setSequenceNumber(sequenceNumber);
    sequenceNumber = (sequenceNumber+1) % 4096;  //XXX seqNum must be checked upon reception of frames!

    transmissionQueue.push_back(frame);

    handleWithFSM(frame);
}

void Ieee80211Mac::handleWithFSM

(

cMessage *

msg

)

[protected, virtual]

Handle all kinds of messages and notifications with the state machine.

Msg can be upper, lower, self or NULL (when radio state changes)

Definition at line 346 of file Ieee80211Mac.cc.

Referenced by handleLowerMsg(), handleSelfMsg(), handleUpperMsg(), and receiveChangeNotification().

{
    // skip those cases where there's nothing to do, so the switch looks simpler
    if (isUpperMsg(msg) && fsm.getState() != IDLE)
    {
        EV << "deferring upper message transmission in " << fsm.getStateName() << " state\n";
        return;
    }

    Ieee80211Frame *frame = dynamic_cast<Ieee80211Frame*>(msg);
    int frameType = frame ? frame->getType() : -1;
    int msgKind = msg->getKind();
    logState();
    stateVector.record(fsm.getState());

    if (frame && isLowerMsg(frame))
    {
        lastReceiveFailed =(msgKind == COLLISION || msgKind == BITERROR);
        scheduleReservePeriod(frame);
    }

    // TODO: fix bug according to the message: [omnetpp] A possible bug in the Ieee80211's FSM.
    FSMA_Switch(fsm)
    {
        FSMA_State(IDLE)
        {
            FSMA_Enter(sendDownPendingRadioConfigMsg());
            FSMA_Event_Transition(Data-Ready,
                                  isUpperMsg(msg),
                                  DEFER,
                ASSERT(isInvalidBackoffPeriod() || backoffPeriod == 0);
                invalidateBackoffPeriod();
            );
            FSMA_No_Event_Transition(Immediate-Data-Ready,
                                     !transmissionQueue.empty(),
                                     DEFER,
                invalidateBackoffPeriod();
            );
            FSMA_Event_Transition(Receive,
                                  isLowerMsg(msg),
                                  RECEIVE,
            );
        }
        FSMA_State(DEFER)
        {
            FSMA_Enter(sendDownPendingRadioConfigMsg());
            FSMA_Event_Transition(Wait-DIFS,
                                  isMediumStateChange(msg) && isMediumFree(),
                                  WAITDIFS,
            ;);
            FSMA_No_Event_Transition(Immediate-Wait-DIFS,
                                     isMediumFree() || !backoff,
                                     WAITDIFS,
            ;);
            FSMA_Event_Transition(Receive,
                                  isLowerMsg(msg),
                                  RECEIVE,
            ;);
        }
        FSMA_State(WAITDIFS)
        {
            FSMA_Enter(scheduleDIFSPeriod());
            FSMA_Event_Transition(Immediate-Transmit-RTS,
                                  msg == endDIFS && !isBroadcast(getCurrentTransmission())
                                  && getCurrentTransmission()->getByteLength() >= rtsThreshold && !backoff,
                                  WAITCTS,
                sendRTSFrame(getCurrentTransmission());
                cancelDIFSPeriod();
            );
            FSMA_Event_Transition(Immediate-Transmit-Broadcast,
                                  msg == endDIFS && isBroadcast(getCurrentTransmission()) && !backoff,
                                  WAITBROADCAST,
                sendBroadcastFrame(getCurrentTransmission());
                cancelDIFSPeriod();
            );
            FSMA_Event_Transition(Immediate-Transmit-Data,
                                  msg == endDIFS && !isBroadcast(getCurrentTransmission()) && !backoff,
                                  WAITACK,
                sendDataFrame(getCurrentTransmission());
                cancelDIFSPeriod();
            );
            FSMA_Event_Transition(DIFS-Over,
                                  msg == endDIFS,
                                  BACKOFF,
                ASSERT(backoff);
                if (isInvalidBackoffPeriod())
                    generateBackoffPeriod();
            );
            FSMA_Event_Transition(Busy,
                                  isMediumStateChange(msg) && !isMediumFree(),
                                  DEFER,
                backoff = true;
                cancelDIFSPeriod();
            );
            FSMA_No_Event_Transition(Immediate-Busy,
                                     !isMediumFree(),
                                     DEFER,
                backoff = true;
                cancelDIFSPeriod();
            );
            // radio state changes before we actually get the message, so this must be here
            FSMA_Event_Transition(Receive,
                                  isLowerMsg(msg),
                                  RECEIVE,
                cancelDIFSPeriod();
            ;);
        }
        FSMA_State(BACKOFF)
        {
            FSMA_Enter(scheduleBackoffPeriod());
            FSMA_Event_Transition(Transmit-RTS,
                                  msg == endBackoff && !isBroadcast(getCurrentTransmission())
                                  && getCurrentTransmission()->getByteLength() >= rtsThreshold,
                                  WAITCTS,
                sendRTSFrame(getCurrentTransmission());
            );
            FSMA_Event_Transition(Transmit-Broadcast,
                                  msg == endBackoff && isBroadcast(getCurrentTransmission()),
                                  WAITBROADCAST,
                sendBroadcastFrame(getCurrentTransmission());
            );
            FSMA_Event_Transition(Transmit-Data,
                                  msg == endBackoff && !isBroadcast(getCurrentTransmission()),
                                  WAITACK,
                sendDataFrame(getCurrentTransmission());
            );
            FSMA_Event_Transition(Backoff-Busy,
                                  isMediumStateChange(msg) && !isMediumFree(),
                                  DEFER,
                cancelBackoffPeriod();
                decreaseBackoffPeriod();
            );
        }
        FSMA_State(WAITACK)
        {
            FSMA_Enter(scheduleDataTimeoutPeriod(getCurrentTransmission()));
            FSMA_Event_Transition(Receive-ACK,
                                  isLowerMsg(msg) && isForUs(frame) && frameType == ST_ACK,
                                  IDLE,
                if (retryCounter == 0) numSentWithoutRetry++;
                numSent++;
                cancelTimeoutPeriod();
                finishCurrentTransmission();
            );
            FSMA_Event_Transition(Transmit-Data-Failed,
                                  msg == endTimeout && retryCounter == transmissionLimit - 1,
                                  IDLE,
                giveUpCurrentTransmission();
            );
            FSMA_Event_Transition(Receive-ACK-Timeout,
                                  msg == endTimeout,
                                  DEFER,
                retryCurrentTransmission();
            );
        }
        // wait until broadcast is sent
        FSMA_State(WAITBROADCAST)
        {
            FSMA_Enter(scheduleBroadcastTimeoutPeriod(getCurrentTransmission()));
            FSMA_Event_Transition(Transmit-Broadcast,
                                  msg == endTimeout,
                                  IDLE,
                finishCurrentTransmission();
                numSentBroadcast++;
            );
        }
        // accoriding to 9.2.5.7 CTS procedure
        FSMA_State(WAITCTS)
        {
            FSMA_Enter(scheduleCTSTimeoutPeriod());
            FSMA_Event_Transition(Receive-CTS,
                                  isLowerMsg(msg) && isForUs(frame) && frameType == ST_CTS,
                                  WAITSIFS,
                cancelTimeoutPeriod();
            );
            FSMA_Event_Transition(Transmit-RTS-Failed,
                                  msg == endTimeout && retryCounter == transmissionLimit - 1,
                                  IDLE,
                giveUpCurrentTransmission();
            );
            FSMA_Event_Transition(Receive-CTS-Timeout,
                                  msg == endTimeout,
                                  DEFER,
                retryCurrentTransmission();
            );
        }
        FSMA_State(WAITSIFS)
        {
            FSMA_Enter(scheduleSIFSPeriod(frame));
            FSMA_Event_Transition(Transmit-CTS,
                                  msg == endSIFS && getFrameReceivedBeforeSIFS()->getType() == ST_RTS,
                                  IDLE,
                sendCTSFrameOnEndSIFS();
                resetStateVariables();
            );
            FSMA_Event_Transition(Transmit-DATA,
                                  msg == endSIFS && getFrameReceivedBeforeSIFS()->getType() == ST_CTS,
                                  WAITACK,
                sendDataFrameOnEndSIFS(getCurrentTransmission());
            );
            FSMA_Event_Transition(Transmit-ACK,
                                  msg == endSIFS && isDataOrMgmtFrame(getFrameReceivedBeforeSIFS()),
                                  IDLE,
                sendACKFrameOnEndSIFS();
                resetStateVariables();
            );
        }
        // this is not a real state
        FSMA_State(RECEIVE)
        {
            FSMA_No_Event_Transition(Immediate-Receive-Error,
                                     isLowerMsg(msg) && (msgKind == COLLISION || msgKind == BITERROR),
                                     IDLE,
                EV << "received frame contains bit errors or collision, next wait period is EIFS\n";
                numCollision++;
                resetStateVariables();
            );
            FSMA_No_Event_Transition(Immediate-Receive-Broadcast,
                                     isLowerMsg(msg) && isBroadcast(frame) && isDataOrMgmtFrame(frame),
                                     IDLE,
                sendUp(frame);
                numReceivedBroadcast++;
                resetStateVariables();
            );
            FSMA_No_Event_Transition(Immediate-Receive-Data,
                                     isLowerMsg(msg) && isForUs(frame) && isDataOrMgmtFrame(frame),
                                     WAITSIFS,
                sendUp(frame);
                numReceived++;
            );
            FSMA_No_Event_Transition(Immediate-Receive-RTS,
                                     isLowerMsg(msg) && isForUs(frame) && frameType == ST_RTS,
                                     WAITSIFS,
            );
            FSMA_No_Event_Transition(Immediate-Receive-Other,
                                     isLowerMsg(msg),
                                     IDLE,
                resetStateVariables();
            );
        }
    }

    logState();
    stateVector.record(fsm.getState());
}

void Ieee80211Mac::initialize

(

int

stage

)

[protected, virtual]

Initialization of the module and some variables.

Reimplemented from WirelessMacBase.

Definition at line 76 of file Ieee80211Mac.cc.

{
    WirelessMacBase::initialize(stage);

    if (stage == 0)
    {
        EV << "Initializing stage 0\n";

        // initialize parameters
        maxQueueSize = par("maxQueueSize");
        bitrate = par("bitrate");
        basicBitrate = 2e6; //FIXME make it parameter
        rtsThreshold = par("rtsThresholdBytes");

        // the variable is renamed due to a confusion in the standard
        // the name retry limit would be misleading, see the header file comment
        transmissionLimit = par("retryLimit");
        if (transmissionLimit == -1) transmissionLimit = 7;
        ASSERT(transmissionLimit > 0);

        cwMinData = par("cwMinData");
        if (cwMinData == -1) cwMinData = CW_MIN;
        ASSERT(cwMinData >= 0);

        cwMinBroadcast = par("cwMinBroadcast");
        if (cwMinBroadcast == -1) cwMinBroadcast = 31;
        ASSERT(cwMinBroadcast >= 0);

        const char *addressString = par("address");
        if (!strcmp(addressString, "auto")) {
            // assign automatic address
            address = MACAddress::generateAutoAddress();
            // change module parameter from "auto" to concrete address
            par("address").setStringValue(address.str().c_str());
        }
        else
            address.setAddress(addressString);

        // subscribe for the information of the carrier sense
        nb->subscribe(this, NF_RADIOSTATE_CHANGED);

        // initalize self messages
        endSIFS = new cMessage("SIFS");
        endDIFS = new cMessage("DIFS");
        endBackoff = new cMessage("Backoff");
        endTimeout = new cMessage("Timeout");
        endReserve = new cMessage("Reserve");
        mediumStateChange = new cMessage("MediumStateChange");

        // interface
        registerInterface();

        // obtain pointer to external queue
        initializeQueueModule();

        // state variables
        fsm.setName("Ieee80211Mac State Machine");
        mode = DCF;
        sequenceNumber = 0;
        radioState = RadioState::IDLE;
        retryCounter = 0;
        backoffPeriod = -1;
        backoff = false;
        lastReceiveFailed = false;
        nav = false;

        // statistics
        numRetry = 0;
        numSentWithoutRetry = 0;
        numGivenUp = 0;
        numCollision = 0;
        numSent = 0;
        numReceived = 0;
        numSentBroadcast = 0;
        numReceivedBroadcast = 0;
        stateVector.setName("State");
        stateVector.setEnum("Ieee80211Mac");
        radioStateVector.setName("RadioState");
        radioStateVector.setEnum("RadioState");

        // initialize watches
        WATCH(fsm);
        WATCH(radioState);
        WATCH(retryCounter);
        WATCH(backoff);
        WATCH(nav);

        WATCH(numRetry);
        WATCH(numSentWithoutRetry);
        WATCH(numGivenUp);
        WATCH(numCollision);
        WATCH(numSent);
        WATCH(numReceived);
        WATCH(numSentBroadcast);
        WATCH(numReceivedBroadcast);
    }
}

void Ieee80211Mac::initializeQueueModule

(

)

[protected, virtual]

Definition at line 209 of file Ieee80211Mac.cc.

Referenced by initialize().

{
    // use of external queue module is optional -- find it if there's one specified
    if (par("queueModule").stringValue()[0])
    {
        cModule *module = getParentModule()->getSubmodule(par("queueModule").stringValue());
        queueModule = check_and_cast<IPassiveQueue *>(module);

        EV << "Requesting first two frames from queue module\n";
        queueModule->requestPacket();
        // needed for backoff: mandatory if next message is already present
        queueModule->requestPacket();
    }
}

void Ieee80211Mac::invalidateBackoffPeriod

(

)

[protected, virtual]

Generates a new backoff period based on the contention window.

Definition at line 732 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    backoffPeriod = -1;
}

bool Ieee80211Mac::isBroadcast

(

Ieee80211Frame *

msg

)

[protected, virtual]

Returns true if message is a broadcast message.

Definition at line 967 of file Ieee80211Mac.cc.

Referenced by buildDataFrame(), computeBackoffPeriod(), and handleWithFSM().

{
    return frame && frame->getReceiverAddress().isBroadcast();
}

bool Ieee80211Mac::isDataOrMgmtFrame

(

Ieee80211Frame *

frame

)

[protected, virtual]

Checks if the frame is a data or management frame.

Definition at line 977 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    return dynamic_cast<Ieee80211DataOrMgmtFrame*>(frame);
}

bool Ieee80211Mac::isForUs

(

Ieee80211Frame *

msg

)

[protected, virtual]

Returns true if message destination address is ours.

Definition at line 972 of file Ieee80211Mac.cc.

Referenced by handleLowerMsg(), handleWithFSM(), and scheduleReservePeriod().

{
    return frame && frame->getReceiverAddress() == address;
}

bool Ieee80211Mac::isInvalidBackoffPeriod

(

)

[protected, virtual]

Definition at line 737 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    return backoffPeriod == -1;
}

bool Ieee80211Mac::isMediumFree

(

)

[protected, virtual]

Tells if the medium is free according to the physical and virtual carrier sense algorithm.

Definition at line 962 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    return radioState == RadioState::IDLE && !endReserve->isScheduled();
}

bool Ieee80211Mac::isMediumStateChange

(

cMessage *

msg

)

[protected, virtual]

Used by the state machine to identify medium state change events. This message is currently optimized away and not sent through the kernel.

Definition at line 957 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    return msg == mediumStateChange || (msg == endReserve && radioState == RadioState::IDLE);
}

void Ieee80211Mac::logState

(

)

[protected, virtual]

Logs all state information.

Definition at line 1012 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    EV  << "state information: mode = " << modeName(mode) << ", state = " << fsm.getStateName()
        << ", backoff = " << backoff << ", backoffPeriod = " << backoffPeriod
        << ", retryCounter = " << retryCounter << ", radioState = " << radioState
        << ", nav = " << nav << endl;
}

const char * Ieee80211Mac::modeName

(

int

mode

)

[protected]

Produce a readable name of the given MAC operation mode.

Definition at line 1020 of file Ieee80211Mac.cc.

Referenced by logState().

{
#define CASE(x) case x: s=#x; break
    const char *s = "???";
    switch (mode)
    {
        CASE(DCF);
        CASE(PCF);
    }
    return s;
#undef CASE
}

virtual int Ieee80211Mac::numInitStages

(

)

const [inline, protected, virtual]

Initialization of the module and its variables.

Definition at line 248 of file Ieee80211Mac.h.

{return 2;}

void Ieee80211Mac::popTransmissionQueue

(

)

[protected, virtual]

Deletes frame at the front of queue.

Definition at line 987 of file Ieee80211Mac.cc.

Referenced by finishCurrentTransmission(), and giveUpCurrentTransmission().

{
    EV << "dropping frame from transmission queue\n";
    Ieee80211Frame *temp = transmissionQueue.front();
    transmissionQueue.pop_front();
    delete temp;

    if (queueModule)
    {
        // tell queue module that we've become idle
        EV << "requesting another frame from queue module\n";
        queueModule->requestPacket();
    }
}

void Ieee80211Mac::receiveChangeNotification	(	int	category,
		const cPolymorphic *	details
	)		[protected, virtual]

Called by the NotificationBoard whenever a change occurs we're interested in.

Implements INotifiable.

Definition at line 324 of file Ieee80211Mac.cc.

{
    Enter_Method_Silent();
    printNotificationBanner(category, details);

    if (category == NF_RADIOSTATE_CHANGED)
    {
        RadioState::State newRadioState = check_and_cast<RadioState *>(details)->getState();

        // FIXME: double recording, because there's no sample hold in the gui
        radioStateVector.record(radioState);
        radioStateVector.record(newRadioState);

        radioState = newRadioState;

        handleWithFSM(mediumStateChange);
    }
}

void Ieee80211Mac::registerInterface

(

)

[protected, virtual]

Definition at line 174 of file Ieee80211Mac.cc.

Referenced by initialize().

{
    IInterfaceTable *ift = InterfaceTableAccess().getIfExists();
    if (!ift)
        return;

    InterfaceEntry *e = new InterfaceEntry();

    // interface name: NetworkInterface module's name without special characters ([])
    char *interfaceName = new char[strlen(getParentModule()->getFullName()) + 1];
    char *d = interfaceName;
    for (const char *s = getParentModule()->getFullName(); *s; s++)
        if (isalnum(*s))
            *d++ = *s;
    *d = '\0';

    e->setName(interfaceName);
    delete [] interfaceName;

    // address
    e->setMACAddress(address);
    e->setInterfaceToken(address.formInterfaceIdentifier());

    // FIXME: MTU on 802.11 = ?
    e->setMtu(par("mtu"));

    // capabilities
    e->setBroadcast(true);
    e->setMulticast(true);
    e->setPointToPoint(false);

    // add
    ift->addInterface(e, this);
}

void Ieee80211Mac::resetStateVariables

(

)

[protected, virtual]

Reset backoff, backoffPeriod and retryCounter for IDLE state.

Definition at line 943 of file Ieee80211Mac.cc.

Referenced by finishCurrentTransmission(), giveUpCurrentTransmission(), and handleWithFSM().

{
    backoffPeriod = 0;
    retryCounter = 0;

    if (!transmissionQueue.empty()) {
        backoff = true;
        getCurrentTransmission()->setRetry(false);
    }
    else {
        backoff = false;
    }
}

void Ieee80211Mac::retryCurrentTransmission

(

)

[protected, virtual]

Definition at line 911 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    ASSERT(retryCounter < transmissionLimit - 1);
    getCurrentTransmission()->setRetry(true);
    retryCounter++;
    numRetry++;
    backoff = true;
    generateBackoffPeriod();
}

void Ieee80211Mac::scheduleBackoffPeriod

(

)

[protected, virtual]

Definition at line 758 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    EV << "scheduling backoff period\n";
    scheduleAt(simTime() + backoffPeriod, endBackoff);
}

void Ieee80211Mac::scheduleBroadcastTimeoutPeriod

(

Ieee80211DataOrMgmtFrame *

frame

)

[protected, virtual]

Definition at line 684 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    EV << "scheduling broadcast timeout period\n";
    scheduleAt(simTime() + computeFrameDuration(frameToSend), endTimeout);
}

void Ieee80211Mac::scheduleCTSTimeoutPeriod

(

)

[protected, virtual]

Definition at line 696 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    scheduleAt(simTime() + computeFrameDuration(LENGTH_RTS, basicBitrate) + getSIFS() + computeFrameDuration(LENGTH_CTS, basicBitrate) + MAX_PROPAGATION_DELAY * 2, endTimeout);
}

void Ieee80211Mac::scheduleDataTimeoutPeriod

(

Ieee80211DataOrMgmtFrame *

frame

)

[protected, virtual]

Definition at line 678 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    EV << "scheduling data timeout period\n";
    scheduleAt(simTime() + computeFrameDuration(frameToSend) + getSIFS() + computeFrameDuration(LENGTH_ACK, basicBitrate) + MAX_PROPAGATION_DELAY * 2, endTimeout);
}

void Ieee80211Mac::scheduleDIFSPeriod

(

)

[protected, virtual]

Definition at line 658 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    if (lastReceiveFailed)
    {
        EV << "receiption of last frame failed, scheduling EIFS period\n";
        scheduleAt(simTime() + getEIFS(), endDIFS);
    }
    else
    {
        EV << "scheduling DIFS period\n";
        scheduleAt(simTime() + getDIFS(), endDIFS);
    }
}

void Ieee80211Mac::scheduleReservePeriod

(

Ieee80211Frame *

frame

)

[protected, virtual]

Schedule network allocation period according to 9.2.5.4.

Definition at line 701 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    simtime_t reserve = frame->getDuration();

    // see spec. 7.1.3.2
    if (!isForUs(frame) && reserve != 0 && reserve < 32768)
    {
        if (endReserve->isScheduled()) {
            simtime_t oldReserve = endReserve->getArrivalTime() - simTime();

            if (oldReserve > reserve)
                return;

            reserve = std::max(reserve, oldReserve);
            cancelEvent(endReserve);
        }
        else if (radioState == RadioState::IDLE)
        {
            // NAV: the channel just became virtually busy according to the spec
            scheduleAt(simTime(), mediumStateChange);
        }

        EV << "scheduling reserve period for: " << reserve << endl;

        ASSERT(reserve > 0);

        nav = true;
        scheduleAt(simTime() + reserve, endReserve);
    }
}

void Ieee80211Mac::scheduleSIFSPeriod

(

Ieee80211Frame *

frame

)

[protected, virtual]

Definition at line 651 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    EV << "scheduling SIFS period\n";
    endSIFS->setContextPointer(frame->dup());
    scheduleAt(simTime() + getSIFS(), endSIFS);
}

void Ieee80211Mac::sendACKFrame

(

Ieee80211DataOrMgmtFrame *

frame

)

[protected, virtual]

Definition at line 781 of file Ieee80211Mac.cc.

Referenced by sendACKFrameOnEndSIFS().

{
    EV << "sending ACK frame\n";
    sendDown(setBasicBitrate(buildACKFrame(frameToACK)));
}

void Ieee80211Mac::sendACKFrameOnEndSIFS

(

)

[protected, virtual]

Definition at line 773 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    Ieee80211Frame *frameToACK = (Ieee80211Frame *)endSIFS->getContextPointer();
    endSIFS->setContextPointer(NULL);
    sendACKFrame(check_and_cast<Ieee80211DataOrMgmtFrame*>(frameToACK));
    delete frameToACK;
}

void Ieee80211Mac::sendBroadcastFrame

(

Ieee80211DataOrMgmtFrame *

frameToSend

)

[protected, virtual]

Definition at line 801 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    EV << "sending Broadcast frame\n";
    sendDown(buildBroadcastFrame(frameToSend));
}

void Ieee80211Mac::sendCTSFrame

(

Ieee80211RTSFrame *

rtsFrame

)

[protected, virtual]

Definition at line 821 of file Ieee80211Mac.cc.

Referenced by sendCTSFrameOnEndSIFS().

{
    EV << "sending CTS frame\n";
    sendDown(setBasicBitrate(buildCTSFrame(rtsFrame)));
}

void Ieee80211Mac::sendCTSFrameOnEndSIFS

(

)

[protected, virtual]

Definition at line 813 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    Ieee80211Frame *rtsFrame = (Ieee80211Frame *)endSIFS->getContextPointer();
    endSIFS->setContextPointer(NULL);
    sendCTSFrame(check_and_cast<Ieee80211RTSFrame*>(rtsFrame));
    delete rtsFrame;
}

void Ieee80211Mac::sendDataFrame

(

Ieee80211DataOrMgmtFrame *

frameToSend

)

[protected, virtual]

Definition at line 795 of file Ieee80211Mac.cc.

Referenced by handleWithFSM(), and sendDataFrameOnEndSIFS().

{
    EV << "sending Data frame\n";
    sendDown(buildDataFrame(frameToSend));
}

void Ieee80211Mac::sendDataFrameOnEndSIFS

(

Ieee80211DataOrMgmtFrame *

frameToSend

)

[protected, virtual]

Definition at line 787 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    Ieee80211Frame *ctsFrame = (Ieee80211Frame *)endSIFS->getContextPointer();
    endSIFS->setContextPointer(NULL);
    sendDataFrame(frameToSend);
    delete ctsFrame;
}

void Ieee80211Mac::sendDownPendingRadioConfigMsg

(

)

[protected, virtual]

Send down the change channel message to the physical layer if there is any.

Definition at line 926 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    if (pendingRadioConfigMsg != NULL)
    {
        sendDown(pendingRadioConfigMsg);
        pendingRadioConfigMsg = NULL;
    }
}

void Ieee80211Mac::sendRTSFrame

(

Ieee80211DataOrMgmtFrame *

frameToSend

)

[protected, virtual]

Definition at line 807 of file Ieee80211Mac.cc.

Referenced by handleWithFSM().

{
    EV << "sending RTS frame\n";
    sendDown(setBasicBitrate(buildRTSFrame(frameToSend)));
}

Ieee80211Frame * Ieee80211Mac::setBasicBitrate

(

Ieee80211Frame *

frame

)

[protected, virtual]

Attaches a PhyControlInfo to the frame which will cause it to be sent at basicBitrate not bitrate (e.g. 2Mbps instead of 11Mbps). Used with ACK, CTS, RTS.

Definition at line 886 of file Ieee80211Mac.cc.

Referenced by sendACKFrame(), sendCTSFrame(), and sendRTSFrame().

{
    ASSERT(frame->getControlInfo()==NULL);
    PhyControlInfo *ctrl = new PhyControlInfo();
    ctrl->setBitrate(basicBitrate);
    frame->setControlInfo(ctrl);
    return frame;
}

void Ieee80211Mac::setMode

(

Mode

mode

)

[protected, virtual]

Change the current MAC operation mode.

Definition at line 935 of file Ieee80211Mac.cc.

{
    if (mode == PCF)
        error("PCF mode not yet supported");

    this->mode = mode;
}

---

Member Data Documentation

MACAddress Ieee80211Mac::address [protected]

MAC address

Definition at line 77 of file Ieee80211Mac.h.

Referenced by buildRTSFrame(), handleLowerMsg(), handleUpperMsg(), initialize(), isForUs(), and registerInterface().

Ieee80211ASFTupleList Ieee80211Mac::asfTuplesList [protected]

A list of last sender, sequence and fragment number tuples to identify duplicates, see spec 9.2.9. TODO: this is not yet used

Definition at line 184 of file Ieee80211Mac.h.

bool Ieee80211Mac::backoff [protected]

True if backoff is enabled

Definition at line 159 of file Ieee80211Mac.h.

Referenced by handleWithFSM(), initialize(), logState(), resetStateVariables(), and retryCurrentTransmission().

simtime_t Ieee80211Mac::backoffPeriod [protected]

Remaining backoff period in seconds

Definition at line 165 of file Ieee80211Mac.h.

Referenced by decreaseBackoffPeriod(), generateBackoffPeriod(), handleWithFSM(), initialize(), invalidateBackoffPeriod(), isInvalidBackoffPeriod(), logState(), resetStateVariables(), and scheduleBackoffPeriod().

double Ieee80211Mac::basicBitrate [protected]

The basic bitrate (1 or 2 Mbps) is used to transmit control frames

Definition at line 83 of file Ieee80211Mac.h.

Referenced by buildACKFrame(), buildCTSFrame(), buildDataFrame(), buildRTSFrame(), initialize(), scheduleCTSTimeoutPeriod(), scheduleDataTimeoutPeriod(), and setBasicBitrate().

double Ieee80211Mac::bitrate [protected]

The bitrate is used to send data and mgmt frames; be sure to use a valid 802.11 bitrate

Definition at line 80 of file Ieee80211Mac.h.

Referenced by computeFrameDuration(), and initialize().

int Ieee80211Mac::cwMinBroadcast [protected]

Contention window size for broadcast messages.

Definition at line 111 of file Ieee80211Mac.h.

Referenced by computeBackoffPeriod(), and initialize().

int Ieee80211Mac::cwMinData [protected]

Minimum contention window.

Definition at line 108 of file Ieee80211Mac.h.

Referenced by computeBackoffPeriod(), and initialize().

cMessage* Ieee80211Mac::endBackoff [protected]

End of the backoff period

Definition at line 206 of file Ieee80211Mac.h.

Referenced by cancelBackoffPeriod(), decreaseBackoffPeriod(), handleWithFSM(), Ieee80211Mac(), initialize(), scheduleBackoffPeriod(), and ~Ieee80211Mac().

cMessage* Ieee80211Mac::endDIFS [protected]

End of the Data Inter-Frame Time period

Definition at line 203 of file Ieee80211Mac.h.

Referenced by cancelDIFSPeriod(), handleWithFSM(), Ieee80211Mac(), initialize(), scheduleDIFSPeriod(), and ~Ieee80211Mac().

cMessage* Ieee80211Mac::endReserve [protected]

End of medium reserve period (NAV) when two other nodes were communicating on the channel

Definition at line 212 of file Ieee80211Mac.h.

Referenced by handleSelfMsg(), Ieee80211Mac(), initialize(), isMediumFree(), isMediumStateChange(), scheduleReservePeriod(), and ~Ieee80211Mac().

cMessage* Ieee80211Mac::endSIFS [protected]

End of the Short Inter-Frame Time period

Definition at line 200 of file Ieee80211Mac.h.

Referenced by getFrameReceivedBeforeSIFS(), handleWithFSM(), Ieee80211Mac(), initialize(), scheduleSIFSPeriod(), sendACKFrameOnEndSIFS(), sendCTSFrameOnEndSIFS(), sendDataFrameOnEndSIFS(), and ~Ieee80211Mac().

cMessage* Ieee80211Mac::endTimeout [protected]

Timeout after the transmission of an RTS, a CTS, or a DATA frame

Definition at line 209 of file Ieee80211Mac.h.

Referenced by cancelTimeoutPeriod(), handleWithFSM(), Ieee80211Mac(), initialize(), scheduleBroadcastTimeoutPeriod(), scheduleCTSTimeoutPeriod(), scheduleDataTimeoutPeriod(), and ~Ieee80211Mac().

const int Ieee80211Mac::fragmentationThreshold = 2346 [static, protected]

Messages longer than this threshold will be sent in multiple fragments. see spec 361

Definition at line 114 of file Ieee80211Mac.h.

Referenced by handleUpperMsg().

cFSM Ieee80211Mac::fsm [protected]

Definition at line 137 of file Ieee80211Mac.h.

Referenced by handleCommand(), handleWithFSM(), initialize(), and logState().

bool Ieee80211Mac::lastReceiveFailed [protected]

Indicates that the last frame received had bit errors in it or there was a collision during receiving the frame. If this flag is set, then the MAC will wait EIFS instead of DIFS period of time in WAITDIFS state.

Definition at line 156 of file Ieee80211Mac.h.

Referenced by handleWithFSM(), initialize(), and scheduleDIFSPeriod().

int Ieee80211Mac::maxQueueSize [protected]

Maximum number of frames in the queue; should be set in the omnetpp.ini

Definition at line 86 of file Ieee80211Mac.h.

Referenced by handleUpperMsg(), and initialize().

cMessage* Ieee80211Mac::mediumStateChange [protected]

Radio state change self message. Currently this is optimized away and sent directly

Definition at line 215 of file Ieee80211Mac.h.

Referenced by Ieee80211Mac(), initialize(), isMediumStateChange(), receiveChangeNotification(), scheduleReservePeriod(), and ~Ieee80211Mac().

Mode Ieee80211Mac::mode [protected]

Definition at line 146 of file Ieee80211Mac.h.

Referenced by initialize(), logState(), and setMode().

bool Ieee80211Mac::nav [protected]

True during network allocation period. This flag is present to be able to watch this state.

Definition at line 162 of file Ieee80211Mac.h.

Referenced by handleSelfMsg(), initialize(), logState(), and scheduleReservePeriod().

long Ieee80211Mac::numCollision [protected]

Definition at line 224 of file Ieee80211Mac.h.

Referenced by handleWithFSM(), and initialize().

long Ieee80211Mac::numGivenUp [protected]

Definition at line 223 of file Ieee80211Mac.h.

Referenced by giveUpCurrentTransmission(), and initialize().

long Ieee80211Mac::numReceived [protected]

Definition at line 226 of file Ieee80211Mac.h.

Referenced by handleWithFSM(), and initialize().

long Ieee80211Mac::numReceivedBroadcast [protected]

Definition at line 228 of file Ieee80211Mac.h.

Referenced by handleWithFSM(), and initialize().

long Ieee80211Mac::numRetry [protected]

Definition at line 221 of file Ieee80211Mac.h.

Referenced by initialize(), and retryCurrentTransmission().

long Ieee80211Mac::numSent [protected]

Definition at line 225 of file Ieee80211Mac.h.

Referenced by handleWithFSM(), and initialize().

long Ieee80211Mac::numSentBroadcast [protected]

Definition at line 227 of file Ieee80211Mac.h.

Referenced by handleWithFSM(), and initialize().

long Ieee80211Mac::numSentWithoutRetry [protected]

Definition at line 222 of file Ieee80211Mac.h.

Referenced by handleWithFSM(), and initialize().

cMessage* Ieee80211Mac::pendingRadioConfigMsg [protected]

The last change channel message received and not yet sent to the physical layer, or NULL. The message will be sent down when the state goes to IDLE or DEFER next time.

Definition at line 193 of file Ieee80211Mac.h.

Referenced by handleCommand(), Ieee80211Mac(), sendDownPendingRadioConfigMsg(), and ~Ieee80211Mac().

IPassiveQueue* Ieee80211Mac::queueModule [protected]

Passive queue module to request messages from

Definition at line 187 of file Ieee80211Mac.h.

Referenced by initializeQueueModule(), and popTransmissionQueue().

RadioState::State Ieee80211Mac::radioState [protected]

Physical radio (medium) state copied from physical layer

Definition at line 174 of file Ieee80211Mac.h.

Referenced by initialize(), isMediumFree(), isMediumStateChange(), logState(), receiveChangeNotification(), and scheduleReservePeriod().

cOutVector Ieee80211Mac::radioStateVector [protected]

Definition at line 230 of file Ieee80211Mac.h.

Referenced by initialize(), and receiveChangeNotification().

int Ieee80211Mac::retryCounter [protected]

Number of frame retransmission attempts, this is a simpification of SLRC and SSRC, see 9.2.4 in the spec

Definition at line 171 of file Ieee80211Mac.h.

Referenced by generateBackoffPeriod(), handleWithFSM(), initialize(), logState(), resetStateVariables(), and retryCurrentTransmission().

int Ieee80211Mac::rtsThreshold [protected]

The minimum length of MPDU to use RTS/CTS mechanism. 0 means always, extremely large value means never. See spec 9.2.6 and 361.

Definition at line 92 of file Ieee80211Mac.h.

Referenced by handleWithFSM(), and initialize().

int Ieee80211Mac::sequenceNumber [protected]

Sequence number to be assigned to the next frame

Definition at line 149 of file Ieee80211Mac.h.

Referenced by handleUpperMsg(), and initialize().

cOutVector Ieee80211Mac::stateVector [protected]

Definition at line 229 of file Ieee80211Mac.h.

Referenced by handleWithFSM(), and initialize().

int Ieee80211Mac::transmissionLimit [protected]

Maximum number of transmissions for a message. This includes the initial transmission and all subsequent retransmissions. Thus a value 0 is invalid and a value 1 means no retransmissions. See: dot11ShortRetryLimit on page 484. 'This attribute shall indicate the maximum number of transmission attempts of a frame, the length of which is less than or equal to dot11RTSThreshold, that shall be made before a failure condition is indicated. The default value of this attribute shall be 7'

Definition at line 105 of file Ieee80211Mac.h.

Referenced by computeBackoffPeriod(), handleWithFSM(), initialize(), and retryCurrentTransmission().

Ieee80211DataOrMgmtFrameList Ieee80211Mac::transmissionQueue [protected]

Messages received from upper layer and to be transmitted later

Definition at line 177 of file Ieee80211Mac.h.

Referenced by getCurrentTransmission(), handleUpperMsg(), handleWithFSM(), popTransmissionQueue(), and resetStateVariables().

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The documentation for this class was generated from the following files:

• Ieee80211Mac.h
• Ieee80211Mac.cc