Presentation Layer

  • All UWB frames can contain an additional payload usually carrying some telemetry data like battery level, metadata about the tag, or data from sensors.

  • The data payload is sent as TLV structures that are inserted in the universal message type, which has msgType = 0x64.

  • The payload is inserted in the message just after the header. The TLV structures are composed (and processed) at the presentation layer, which takes the data request from applications or system routines and append a payload.

  • The frame has the following structure:

MAC header

msgType

TLV_0

TLV_1

…..

TLV_N

CRC

any type of MAC header

0x64

payload data

crc16

  • The UWB frame can also contain another msgTypes with or without an additional payload. Those are msgTypes 0xFC (charging mark) or 0xFD (sleep_mode mark). These marks indicate that the tag is charging or that the tag is in sleep mode. So the final form can be as follows:


UWB frame for tags in charging state (without payload):

MAC header

msgType

CRC

any type of MAC header

0xFC

crc16

(with payload):

MAC header

msgType/
mark

msgType

TLV_0

TLV_1

…..

TLV_N

CRC

any type of MAC header

0xFC

0x64

payload data

crc16

UWB frame for tags in sleep mode (without payload):

MAC header

msgType

CRC

any type of MAC header

0xFD

crc16

(with payload):

MAC header

msgType/
mark

msgType

TLV_0

TLV_1

…..

TLV_N

CRC

any type of MAC header

0xFD

0x64

payload data

crc16