changed symbols_to_integer to dibits_to_integer
git-svn-id: http://op25.osmocom.org/svn/trunk@31 65a5c917-d112-43f1-993d-58c26a4786be
This commit is contained in:
mossmann
parent
3a075f2488
commit
2d0030dde8
|
|
@ -44,12 +44,12 @@ def average(list):
|
|||
for num in list: total += num
|
||||
return total / len(list)
|
||||
|
||||
# return integer represented by sequence of symbols (dibits)
|
||||
def symbols_to_integer(symbols):
|
||||
# return integer represented by sequence of dibits
|
||||
def dibits_to_integer(dibits):
|
||||
integer = 0
|
||||
for symbol in symbols:
|
||||
for dibit in dibits:
|
||||
integer = integer << 2
|
||||
integer += symbol
|
||||
integer += dibit
|
||||
return integer
|
||||
|
||||
# extract a block of symbols from in between status symbols
|
||||
|
|
@ -91,7 +91,7 @@ def trellis_1_2_decode(input):
|
|||
state = 0
|
||||
# cycle through 2 symbol codewords in input
|
||||
for i in range(0,len(input),2):
|
||||
codeword = symbols_to_integer(input[i:i+2])
|
||||
codeword = dibits_to_integer(input[i:i+2])
|
||||
similarity = [0, 0, 0, 0]
|
||||
# compare codeword against each of four candidates for the current state
|
||||
for candidate in range(4):
|
||||
|
|
@ -123,7 +123,7 @@ def trellis_3_4_decode(input):
|
|||
state = 0
|
||||
# cycle through 2 symbol codewords in input
|
||||
for i in range(0,len(input),2):
|
||||
codeword = symbols_to_integer(input[i:i+2])
|
||||
codeword = dibits_to_integer(input[i:i+2])
|
||||
similarity = [0, 0, 0, 0, 0, 0, 0, 0]
|
||||
# compare codeword against each of eight candidates for the current state
|
||||
for candidate in range(8):
|
||||
|
|
@ -213,7 +213,7 @@ def cyclic_16_8_5_decode(input):
|
|||
# TODO: de-randomization
|
||||
# TODO: de-interleaving
|
||||
def imbe_decode(input):
|
||||
print "Raw IMBE frame: 0x%036x" % (symbols_to_integer(input))
|
||||
print "Raw IMBE frame: 0x%036x" % (dibits_to_integer(input))
|
||||
|
||||
# correlate (multiply-accumulate) frame sync
|
||||
def correlate(start):
|
||||
|
|
@ -309,17 +309,17 @@ def decode_frame(symbols):
|
|||
consumed = 0
|
||||
status_symbols = []
|
||||
|
||||
print "Frame Sync: 0x%012x" % symbols_to_integer(symbols[0:24])
|
||||
print "Frame Sync: 0x%012x" % dibits_to_integer(symbols[0:24])
|
||||
consumed += 24
|
||||
|
||||
nid_symbols, block_status_symbols, block_consumed = extract_block(symbols, 32, consumed)
|
||||
status_symbols.extend(block_status_symbols)
|
||||
consumed += block_consumed
|
||||
network_id = bch_64_16_23_decode(nid_symbols)
|
||||
network_access_code = symbols_to_integer(network_id[:6])
|
||||
data_unit_id = symbols_to_integer(network_id[6:])
|
||||
network_access_code = dibits_to_integer(network_id[:6])
|
||||
data_unit_id = dibits_to_integer(network_id[6:])
|
||||
|
||||
print "NID codeword: 0x%016x" % (symbols_to_integer(nid_symbols))
|
||||
print "NID codeword: 0x%016x" % (dibits_to_integer(nid_symbols))
|
||||
print "Network Access Code: 0x%03x, Data Unit ID: 0x%01x" % (network_access_code, data_unit_id)
|
||||
|
||||
if data_unit_id == 7:
|
||||
|
|
@ -336,7 +336,7 @@ def decode_frame(symbols):
|
|||
tsbk = trellis_1_2_decode(data_deinterleave(tsbk_symbols))
|
||||
# TODO: verify with CRC
|
||||
# TODO: see 102.AABC-B for further decoding
|
||||
print "TSBK: 0x%025x" % (symbols_to_integer(tsbk))
|
||||
print "TSBK: 0x%025x" % (dibits_to_integer(tsbk))
|
||||
last_block_flag = tsbk[0] >> 1
|
||||
elif data_unit_id == 12:
|
||||
print "Found a Packet Data Unit"
|
||||
|
|
@ -350,34 +350,34 @@ def decode_frame(symbols):
|
|||
# I/O indicates direction of message (1 = outbound, 0 = inbound), 1 bit
|
||||
io = header[1] >> 1
|
||||
# Format of PDU, 5 bits
|
||||
format = symbols_to_integer(header[1:4]) & 0x1F
|
||||
format = dibits_to_integer(header[1:4]) & 0x1F
|
||||
# TODO: header crc_ccitt error detection
|
||||
if format == 0x16:
|
||||
print "PDU is a Confirmed Data Packet"
|
||||
# block length in octets
|
||||
block_size = 16
|
||||
# Service Access Point (SAP) to which the message is directed, 6 bits
|
||||
sap_id = symbols_to_integer(header[4:8]) & 0x3F
|
||||
sap_id = dibits_to_integer(header[4:8]) & 0x3F
|
||||
# Manufacturer's ID (MFID) 8 bits
|
||||
manufacturers_id = symbols_to_integer(header_data_unit[8:12])
|
||||
manufacturers_id = dibits_to_integer(header_data_unit[8:12])
|
||||
# Logical Link ID, 24 bits
|
||||
logical_link_id = symbols_to_integer(header_data_unit[12:24])
|
||||
logical_link_id = dibits_to_integer(header_data_unit[12:24])
|
||||
# Full Message Flag (FMF) (1 for first try, 0 for retries), 1 bit
|
||||
fmf = header[24] >> 1
|
||||
# Blocks to Follow, 7 bits
|
||||
blocks_to_follow = symbols_to_integer(header[24:28]) & 0x7F
|
||||
blocks_to_follow = dibits_to_integer(header[24:28]) & 0x7F
|
||||
# Pad Octet Count, 5 bits
|
||||
pad_octet_count = symbols_to_integer(header[29:32]) & 0x1F
|
||||
pad_octet_count = dibits_to_integer(header[29:32]) & 0x1F
|
||||
# Synchronize (Syn), 1 bit
|
||||
syn = header[32] >> 1
|
||||
# Sequence Number (N(S)), 3 bits
|
||||
sequence_number = symbols_to_integer(header[32:34]) & 0x7
|
||||
sequence_number = dibits_to_integer(header[32:34]) & 0x7
|
||||
# Fragment Sequence Number Field (FSNF), 4 bits
|
||||
fragment_sequence_number = symbols_to_integer(header[34:36])
|
||||
fragment_sequence_number = dibits_to_integer(header[34:36])
|
||||
# Data Header Offset, 6 bits
|
||||
data_header_offset = symbols_to_integer(header[36:40]) & 0x3F
|
||||
data_header_offset = dibits_to_integer(header[36:40]) & 0x3F
|
||||
# Header CRC, 16 bits
|
||||
header_crc = symbols_to_integer(header[40:48])
|
||||
header_crc = dibits_to_integer(header[40:48])
|
||||
# TODO: verify header CRC
|
||||
user_data = []
|
||||
for i in range(blocks_to_follow):
|
||||
|
|
@ -399,20 +399,20 @@ def decode_frame(symbols):
|
|||
# block length in octets
|
||||
block_size = 12
|
||||
response_class = header[4]
|
||||
response_type = symbols_to_integer(header[5:7]) & 0xE
|
||||
response_status = symbols_to_integer(header[6:8]) & 0x3
|
||||
response_type = dibits_to_integer(header[5:7]) & 0xE
|
||||
response_status = dibits_to_integer(header[6:8]) & 0x3
|
||||
# Manufacturer's ID (MFID) 8 bits
|
||||
manufacturers_id = symbols_to_integer(header_data_unit[8:12])
|
||||
manufacturers_id = dibits_to_integer(header_data_unit[8:12])
|
||||
# Logical Link ID, 24 bits
|
||||
logical_link_id = symbols_to_integer(header_data_unit[12:24])
|
||||
logical_link_id = dibits_to_integer(header_data_unit[12:24])
|
||||
# X, 1 bit
|
||||
x = header[24] >> 1
|
||||
# Blocks to Follow, 7 bits
|
||||
blocks_to_follow = symbols_to_integer(header[24:28]) & 0x7F
|
||||
blocks_to_follow = dibits_to_integer(header[24:28]) & 0x7F
|
||||
# Source Logical Link ID, 24 bits
|
||||
source_logical_link_id = symbols_to_integer(header_data_unit[28:40])
|
||||
source_logical_link_id = dibits_to_integer(header_data_unit[28:40])
|
||||
# Header CRC, 16 bits
|
||||
header_crc = symbols_to_integer(header[40:48])
|
||||
header_crc = dibits_to_integer(header[40:48])
|
||||
# TODO: verify header CRC
|
||||
response_data = []
|
||||
for i in range(blocks_to_follow):
|
||||
|
|
@ -431,19 +431,19 @@ def decode_frame(symbols):
|
|||
# block length in octets
|
||||
block_size = 12
|
||||
# Service Access Point (SAP) to which the message is directed, 6 bits
|
||||
sap_id = symbols_to_integer(header[4:8]) & 0x3F
|
||||
sap_id = dibits_to_integer(header[4:8]) & 0x3F
|
||||
# Manufacturer's ID (MFID) 8 bits
|
||||
manufacturers_id = symbols_to_integer(header_data_unit[8:12])
|
||||
manufacturers_id = dibits_to_integer(header_data_unit[8:12])
|
||||
# Logical Link ID, 24 bits
|
||||
logical_link_id = symbols_to_integer(header_data_unit[12:24])
|
||||
logical_link_id = dibits_to_integer(header_data_unit[12:24])
|
||||
# Blocks to Follow, 7 bits
|
||||
blocks_to_follow = symbols_to_integer(header[24:28]) & 0x7F
|
||||
blocks_to_follow = dibits_to_integer(header[24:28]) & 0x7F
|
||||
# Pad Octet Count, 5 bits
|
||||
pad_octet_count = symbols_to_integer(header[29:32]) & 0x1F
|
||||
pad_octet_count = dibits_to_integer(header[29:32]) & 0x1F
|
||||
# Data Header Offset, 6 bits
|
||||
data_header_offset = symbols_to_integer(header[36:40]) & 0x3F
|
||||
data_header_offset = dibits_to_integer(header[36:40]) & 0x3F
|
||||
# Header CRC, 16 bits
|
||||
header_crc = symbols_to_integer(header[40:48])
|
||||
header_crc = dibits_to_integer(header[40:48])
|
||||
# TODO: verify header CRC
|
||||
user_data = []
|
||||
for i in range(blocks_to_follow):
|
||||
|
|
@ -476,21 +476,21 @@ def decode_frame(symbols):
|
|||
header_data_unit = rs_36_20_17_decode(rs_codeword)
|
||||
# Message Indicator (MI) 72 bits
|
||||
message_indicator = header_data_unit[:36]
|
||||
print "Message Indicator: 0x%018x" % (symbols_to_integer(message_indicator))
|
||||
print "Message Indicator: 0x%018x" % (dibits_to_integer(message_indicator))
|
||||
# Manufacturer's ID (MFID) 8 bits
|
||||
manufacturers_id = header_data_unit[36:40]
|
||||
print "Manufacturer's ID: 0x%02x" % (symbols_to_integer(manufacturers_id))
|
||||
if symbols_to_integer(manufacturers_id) > 0:
|
||||
print "Manufacturer's ID: 0x%02x" % (dibits_to_integer(manufacturers_id))
|
||||
if dibits_to_integer(manufacturers_id) > 0:
|
||||
print "Non-standard Manufacturer's ID"
|
||||
# Algorithm ID (ALGID) 8 bits
|
||||
algorithm_id = header_data_unit[40:44]
|
||||
print "Algorithm ID: 0x%02x" % (symbols_to_integer(algorithm_id))
|
||||
print "Algorithm ID: 0x%02x" % (dibits_to_integer(algorithm_id))
|
||||
# Key ID (KID) 16 bits
|
||||
key_id = header_data_unit[44:52]
|
||||
print "Key ID: 0x%04x" % (symbols_to_integer(key_id))
|
||||
print "Key ID: 0x%04x" % (dibits_to_integer(key_id))
|
||||
# Talk-group ID (TGID) 16 bits
|
||||
talk_group_id = header_data_unit[52:60]
|
||||
print "Talk Group ID: 0x%04x" % (symbols_to_integer(talk_group_id))
|
||||
print "Talk Group ID: 0x%04x" % (dibits_to_integer(talk_group_id))
|
||||
elif data_unit_id == 3:
|
||||
print "Found a Terminator Data Unit without subsequent Link Control"
|
||||
# terminator used after superframe
|
||||
|
|
@ -506,7 +506,7 @@ def decode_frame(symbols):
|
|||
golay_codewords = terminator_symbols[:144]
|
||||
rs_codeword = golay_24_12_8_decode(golay_codewords)
|
||||
link_control = rs_24_12_13_decode(rs_codeword)
|
||||
print "Link Control: 0x%018x" % (symbols_to_integer(link_control))
|
||||
print "Link Control: 0x%018x" % (dibits_to_integer(link_control))
|
||||
elif data_unit_id == 5:
|
||||
print "Found a Logical Link Data Unit 1 (LDU1)"
|
||||
# contains voice frames 1 through 9 of a superframe
|
||||
|
|
@ -529,13 +529,13 @@ def decode_frame(symbols):
|
|||
low_speed_data_symbols = ldu_symbols[696:712]
|
||||
link_control_rs_codeword = hamming_10_6_3_decode(link_control_symbols)
|
||||
link_control = rs_24_12_13_decode(link_control_rs_codeword)
|
||||
print "Link Control: 0x%018x" % (symbols_to_integer(link_control))
|
||||
print "Link Control: 0x%018x" % (dibits_to_integer(link_control))
|
||||
link_control_format = link_control[:4]
|
||||
print "Link Control Format: 0x%02x" % (symbols_to_integer(link_control_format))
|
||||
print "Link Control Format: 0x%02x" % (dibits_to_integer(link_control_format))
|
||||
# rest of link control frame is 64 bits of fields specified by LCF
|
||||
# likeliy to include TGID, Source ID, Destination ID, Emergency indicator, MFID
|
||||
low_speed_data = cyclic_16_8_5_decode(low_speed_data_symbols)
|
||||
print "Low Speed Data: 0x%04x" % (symbols_to_integer(low_speed_data))
|
||||
print "Low Speed Data: 0x%04x" % (dibits_to_integer(low_speed_data))
|
||||
# spec says Low Speed Data = 32 bits data + 32 bits parity
|
||||
# huh? Is the other half in LDU2?
|
||||
elif data_unit_id == 10:
|
||||
|
|
@ -560,18 +560,18 @@ def decode_frame(symbols):
|
|||
low_speed_data_symbols = ldu_symbols[696:712]
|
||||
encryption_sync_rs_codeword = hamming_10_6_3_decode(encryption_sync_symbols)
|
||||
encryption_sync = rs_24_16_9_decode(encryption_sync_rs_codeword)
|
||||
print "Encryption Sync Word: 0x%024x" % (symbols_to_integer(encryption_sync))
|
||||
print "Encryption Sync Word: 0x%024x" % (dibits_to_integer(encryption_sync))
|
||||
# Message Indicator (MI) 72 bits
|
||||
message_indicator = encryption_sync[:36]
|
||||
print "Message Indicator: 0x%018x" % (symbols_to_integer(message_indicator))
|
||||
print "Message Indicator: 0x%018x" % (dibits_to_integer(message_indicator))
|
||||
# Algorithm ID (ALGID) 8 bits
|
||||
algorithm_id = encryption_sync[36:40]
|
||||
print "Algorithm ID: 0x%02x" % (symbols_to_integer(algorithm_id))
|
||||
print "Algorithm ID: 0x%02x" % (dibits_to_integer(algorithm_id))
|
||||
# Key ID (KID) 16 bits
|
||||
key_id = encryption_sync[40:48]
|
||||
print "Key ID: 0x%04x" % (symbols_to_integer(key_id))
|
||||
print "Key ID: 0x%04x" % (dibits_to_integer(key_id))
|
||||
low_speed_data = cyclic_16_8_5_decode(low_speed_data_symbols)
|
||||
print "Low Speed Data: 0x%04x" % (symbols_to_integer(low_speed_data))
|
||||
print "Low Speed Data: 0x%04x" % (dibits_to_integer(low_speed_data))
|
||||
else:
|
||||
print "unknown Data Unit ID"
|
||||
# TODO: maybe extract status symbol after nulls
|
||||
|
|
|
|||
Reference in New Issue