Simple Module Ieee802154NarrowbandMac

Package: inet.linklayer.ieee802154
File: src/inet/linklayer/ieee802154/Ieee802154NarrowbandMac.ned

C++ definition

(no description)

Usage diagram:

The following diagram shows usage relationships between types. Unresolved types are missing from the diagram.

Inheritance diagram:

The following diagram shows inheritance relationships for this type. Unresolved types are missing from the diagram.

Extends:

Name	Type	Description
CSMA	simple module	Generic CSMA protocol supporting Mac-ACKs as well as constant, linear or exponential backoff times.

Used in compound modules:

Name	Type	Description
Ieee802154NarrowbandNic	compound module	(no description)

Parameters:

Name	Type	Default value	Description
interfaceTableModule	string
address	string	"auto"	MAC address as hex string (12 hex digits), or "auto". "auto" values will be replaced by a generated MAC address in init stage 0.
headerLength	int	72 bit	length of MAC header
mtu	int	127 Byte - 9 Byte
queueLength	int	100	size of the MAC queue (maximum number of packets in Tx buffer)
bitrate	double	250000 bps	bit rate
ccaDetectionTime	double	0.000128 s	Clear Channel Assessment detection time
rxSetupTime	double	0s	Time to setup radio to reception state
aTurnaroundTime	double	0.000192 s	Time to switch radio from Rx to Tx state
useMACAcks	bool	true	Send/Expect MAC acks for unicast traffic?
macMaxFrameRetries	int	3	Maximum number of frame retransmission, only used when usage of MAC acks is enabled.
macAckWaitDuration	double	0.00056 s	Time to wait for an acknowledgement after transmitting a unicast frame. Only used when usage of MAC acks is enabled. Value is calculated from 1+12+10+12 symbols, which is defined for nonbeacon-enabled PAN. In the non-beacon-enabled case, the receiver responds at aTurnaroundTime (i.e. the time for the sender and receiver to both be guaranteed to have switched from Tx to Rx and vice verse). This gives the value 192us + 352us = 544us (there's been some discussion about the "extra" 1 symbol == 16us) [section 7.5.6.4.2 of the specification].
ackLength	double	40 bit	Complete MAC ack message length (in bits) (! headerLength is not added to this), only used when usage of MAC acks is enabled.
sifs	double	0.000192 s	Simple interframe space (12 symbols). Time to wait between receiving a frame and acknowledging it. Should be bigger than the maximum time for switching between Tx and Rx at the receiver. Only used when usage of MAC acks is enabled.
backoffMethod	string	"exponential"	Backoff method to use: constant, linear or exponential
macMaxCSMABackoffs	int	4	maximum number of extra backoffs (excluding the first unconditional one) before frame drop
aUnitBackoffPeriod	double	0.00032 s	base unit for all backoff calculations
contentionWindow	int	2	# of backoff periods of the initial contention window (for linear and constant backoff method only)
macMinBE	double	3	minimum backoff exponent (for exponential backoff method only)
macMaxBE	double	5	maximum backoff exponent (for exponential backoff method only)
radioModule	string	"^.radio"	The path to the Radio module //FIXME remove default value

Properties:

Name	Value	Description
display	i=block/rxtx
class	CSMA

Gates:

Name	Direction	Size	Description
upperLayerIn	input
upperLayerOut	output
lowerLayerIn	input
lowerLayerOut	output

Signals:

Name	Type	Unit
NF_LINK_BREAK	CSMAFrame

Source code:

simple Ieee802154NarrowbandMac extends CSMA
{
    parameters:
        useMACAcks = true;

        // Time needed to switch from sleep to rx.
        // TODO This is probabily wrong, since it is used to compute
        //      the time for the CCA (and that might follow an RX state)
        rxSetupTime = 0s;

        // aMaxPHYPacketSize = 127 Octets (802.15.4-2006, page 45)
        // aMinMPDUOverhead = 9 Octets (802.15.4-2006, page 159)
        // aMaxMACPayloadSize = aMaxPHYPacketSize - aMinMPDUOverhead (802.15.4-2006, page 159)
        mtu = 127 Byte - 9 Byte;

        // length of MAC header
        // aMinMPDUOverhead = 9 Octets (802.15.4-2006, page 159)
        headerLength = default(72 bit);

        // Exponential Backoff
        backoffMethod = default("exponential");

        // Maximum number of frame retransmission
        // 802.15.4-2006, page 164
        macMaxFrameRetries = default(3);

        // Maximum number of extra backoffs (excluding the first unconditional one) before frame drop
        // 802.15.4-2006, page 163
        macMaxCSMABackoffs = default(4);

        // Minimum backoff exponent
        // 802.15.4-2006, page 164
        macMinBE = default(3);

        // Maximum backoff exponent
        // 802.15.4-2006, page 163
        macMaxBE = default(5);
}