MAC Command Frame

The command frames defined by MAC sublayer are listed in this table
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An FFD (Full-Function Device) shall be capable of transmitting and receiving all command frame types, with the exception of the GTS request command, while the requirements for an RFD (Reduced-Function Device) are indicated by an “X” in the table. MAC commands shall only be transmitted in the CAP for beaon-enabled PANs or at any time for nonbeacon-enabled PANs.

1. Association Request Command
this command allows a device to request association with a PAN through the PAN coordinator or coordinator.
Figure of Association request command format :
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1.1 MHR field.
Let see standard page 150 for detail.

1.2 Capability Information field.
Figure :
f56.jpg

The Alternate PAN coordinator subfield is 1 bit in length and shall be set to one if the device is capable of becoming the PAN coordinator.

The Device Type subfield is 1 bit in length and shall be set to one if the device is an FFD. Otherwise, the Device type subfield shall be set to zero to indicate an RFD.

The Power source subfield is 1 bit in length and shall be set to one if the device is receiving power from the alternating current mains.

The receiver On when Idle subfield is 1 bit in length and shall be set to one if the device does not disable its receiver to conserve power during idle periods.

The security capability subfield is 1 bit in length and shall be set to one if the device is capable of sending and receiving cryptographically protected MAC frames.

The allocate address subfield is 1 bit in length and shall be set to one if the device wishes the coordinator to allocate a 16-bit short address as a result of the association procedure.

2. Association Response Command.
it allows the PAN coordinator or a coordinator to communicate the results of an association attempt back to the device requesting association.

This command shall only be sent by PAN coordinator or coordinator to a device that is currently trying to associate.
Figure:
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2.1 MHR fields
Let see standard on page 151.

2.2 Short Address field
If the coordinator was not able to associate this device to its PAN, the short address field shall be set to 0xffff, and the association status field shall contain the reason for the failure.

2.3 Association Status field.
Table:.
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3. Disassociation Notification Command.
The PAN coordinator, a coordinator, or an associated device may send the disassociate notification command.All devices shall implement this command.

Figure:
f58.jpg

3.1 MHR fields.
Let see standard on page 153.

3.2 Disassociation Reason field.
Table:
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4. Data Request command.
it sent by a device to request data from the PAN coordinator or a coordinator.
Let see standard on page 153-154, very complex.

5. PAN ID conflict notification command.
The PAN ID conflict notification command is sent by a device to the PAN coordinator when a PAN identifier conflivt is detected.

6. Orphan Notification Command
it used by an associated device that has lost synchronization with its coordinator.

7. Beacon Request command
it used by a device to locate all coordinators within its POS (Personal Operating Space) during an active scan.
this command is optional for an RFD.

8. Coordinator Realignment command.
it sent by the PAN coordinator either following the reception of an orphan notification command from a device that is recognized to be on its PAN or when ant of its PAN configuration attributes change due to the receipt of an MLME-START.request primitive. (MLME = MAC sublayer management entity).
If this command is sent following the reception of an orphan notification command, it is sent directly to the orphaned device. If this command is sent when any PAN configuration attributes change, it is broadcast to the PAN.

Figure:
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Let see standard on page 156-157 for more detail about these figure.

9. GTS request command
it is used by an associated device that is requesting the allocation of a new GTS (guaranteed time slots) or the deallocation of an existing GTS from the PAN coordinator.
this command is optional.
Figure:
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9.1 MHR fields.
Let see standard on page 158.

9.2 GTS Characteristics field.
Figure :
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The GTS Length subfield shall contain the number of superframe slots being requested for the GTS.

The GTS direction subfield shall be set to one if the GTS is to be a receive-only GTS, it shall be set to zero if the GTS is to be a transmit-only GTS.

The Chatacteristics type subfield shall be set to one if the characteristics refers to a GTS allocation or zero if the characteristics refers to a GTS deallocation.

Reference :
IEEE Standard for Information technology, Specifications for WPANs 802.15.4

you must find your own research style by yourself,

January 28 2008 – Winter Vacation,
Taipei City
High Speed Network Lab

Udin Harun

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