0xBA - backchannel acknowledgment

This MAC header type is sent by tag after the backchannel data message from the anchor is successfully received.

Structure of BA MAC header:

typedef struct __attribute__((packed, aligned(1))){
     uint8_t fcode;
     uint8_t MAC_addr[MAC_ADDR_BYTE_SIZE];
     uint8_t seqNum;
     uint8_t BC_version;
     uint8_t BC_ack_num[BC_ACK_NUM_SIZE];
} mac_header_ba_t;

field	description	length
fcode	MAC header type identifier - 0xBA for acknowledgment	1B
MAC_addr	MAC address of the tag	6B
seqNum	Sequence number of the blink.	1B
BC_version	Version of backchannel protocol	1B
BC_ack_num	Acknowledgment number - this number is generated by server for every BC transaction. Tag do not interpret it. It only put the last received transaction number into ACK header.	5B