This is the latest UWB frame protocol specification compliant with Sewio infrastructure.

Requirements:

RTLS Studio: version 2.6.0 or newer
Anchor FW: version 3.1.6 or newer
Tag FW: version 3.127.7 or newer
Tag Leonardo Configurator 1.3.2 or newer
Setting → Blink Profile = RF5

How-to

The full UWB frames contain various overhead fields which are appended as it goes from APP to PHY layer.

Sewio UWB frame encapsulation example from APP to PHY Layer

Briefly on the layers

Physical Layer

Physical layer. The lowest layer of the system. This layer knows nothing about the content of the transmitted frame. The only information that is given to this layer is the length of the frame and the frame itself as an array of data bytes. This frame is processed by a UWB transceiver.

MAC Layer

MAC layer ensures the successful transfer of the frame from point A to point B. So the following fields are used by this layer:

MAC_header
- fcode - frame control field - it is used to determine what kind of UWB frame it is. Based on this field the individual nodes can decide whether to drop the packet or process it.
- srcAddr - this field uniquely identifies the sender of the frame. This field may not be included in all UWB messages. In some cases, it is not important to know who sent the message
- destAddr - the address of the node for which the message is intended. This field may not be included in all UWB messages.
- seqNum - sequence number of the message. It is incremented modulo 256.
- BC_num -number of BC_sequence. The tag sends the number of the last successful BC transaction. It is used by the Anchor to recognize if the tag receives the message, that was sent to the anchor by it.
- BC_opt* - back-channel options. This field is sent only in back-channel data messages from Anchor to Tag. It contains optional parameters of back-channel behavior (immediate ACK etc.).
- MAC_footer
  - CRC16 - cyclic redundancy check. Additional CRC to ensure consistency of the packet. (CRC is also added at the PHY layer, however, this is not enough ).

BC_opt[n]	BC_opt[n-1]	BC_opt[n-2]
n - this field contains lentgt of BC_opt parameters - it be extended in the future	number of ACK retransmissions after successful receive of back-channel	immediate AC

Presentation Layer

This layer act as a multiplexer. It takes the raw data from the frame and passes it to the specific application.

Application Layer

This is the top layer where the user payload is sent and received.

Examples of UWB frames

The simplest blink without any application or system data

PHY layer	MAC layer			PHY layer
PHY header	fcode	srcAddr	seqNum	PHY footer
(generated by DW1000)	0xBB	0x22035eb14066	0x20	CRC16 (generated by DW1000)

The blink with battery level

PHY layer	MAC layer			presentation layer	APP layer			PHY layer
PHY heade	fcode	srcAddr	seqNum	msgType	APP ID	length	APP data	PHY footer
(generated by DW1000)	0xBB	0x22035eb14066	0x20	0x64	0x0001	0x01	0xC8	CRC16 (generated by DW1000)

The blink with battery level and barometer data

PHY layer

MAC layer

presentation layer

APP layer*

PHY heade

fcode

srcAddr

seqNum

msgType

APP ID

length

APP data (battery level)

(generated by DW1000)

0xBB

0x22035eb14066

0x20

0x64

0x0001

(batt lvl)

0x01

0xC8

APP layer			PHY layer
APP ID	length	APP data (baro data)	PHY footer
0x0005 (sensors data)	0x05	0x08AABBCCDD	CRC16 (generated by DW1000)

*at APP layer can be data from multiple application

Let's continue with layer details here: