ok-dmrlib 0.6

Parse, assemble and handle DMR data

OK-DMR Lib

This package provides way to parse and assemble various DMR ETSI protocols and functions, in pure Python implementation

Supported features

FEC (Forward Error Correction)

Algorithm	Encoding	Decoding / Verification
Hamming (7,4,3)	✅	✅
Hamming (13,9,3)	✅	✅
Hamming (15,11,3)	✅	✅
Hamming (16,11,3)	✅	✅
Hamming (17,12,3)	✅	✅
Golay (20,8,7)	✅	✅
Quadratic Residue (16,7,6)	✅	✅
Reed-Solomon (12,9,4)	✅	✅
Rate 3/4 Trellis	✅	✅
Block Product Turbo Code (196,96)	✅	✅
Variable length BPTC (BPTC 128,72)	✅	✅
Variable length BPTC (BPTC 68,28) for CACH/Short LC	✅	✅
Variable length BTPC (BPTC 32,11) for Single-Burst	✅	✅

CRC (Cyclic Redundancy Check) and Checksums

Name	Generate	Verify
5-bit checksum	✅	✅
CRC-8 (8-bit CRC)	✅	✅
CRC-9	✅	✅
CRC-CCIT (CRC16-CCIT)	✅	✅
CRC-32 (32-bit CRC)	✅	✅

ETSI PDUs (Protocol Data Units)

Name	Encoding / Decoding	Description
CSBK	✅	Control Signalling Block, namely: BS Outbound Activation, Unit-Unit Request/Answer, Negative ACK, Preamble, Channel Timing
EMB	✅	Embedded Signalling
FULL LC	✅	Full Link Control, namely: Group Voice, Unit-Unit, Talker Alias (header + blocks1,2,3), GPSInfo, Terminator with LC
SHORT LC	✅	Short Link Control, namely: Activity, Null
SLOT	✅	Slot Type
SYNC	✅	Synchronization patterns
Data Header	✅	Confirmed/Unconfirmed, Response, Defined Short Data
PI Header	✅	Privacy (PI) Header, without further understanding of transported data
Rate 1 Data	✅	Rate 1 data (confirmed and unconfirmed) and last block data (confirmed and unconfirmed)
Rate 1/2 Data	✅	Rate 1/2 data (confirmed and unconfirmed) and last block data (confirmed and unconfirmed)
Rate 3/4 Data	✅	Rate 3/4 data (confirmed and unconfirmed) and last block data (confirmed and unconfirmed)

ETSI Information Elements

All listed elements are supported as standalone enum/class representation, which allows for decoding/encoding and describing data (discovery):

Access Types (AT), CRC Mask, CSBKO (CSBK Opcode), DPF (Data Packet Format), DT (Data Type), FID (Feature Set ID), FLCO ( Full LC Opcode), LCSS (LC Start/Stop), PI (Pre-emption and power control indicator), SLCO (Short LC Opcode), SYNC ( Synchronization pattern), Activity ID, Additional Information Field, Answer/Response, CTO (Channel Timing Opcode), DI ( Dynamic Identifier), Position Error, Reason Code, Service Options, Talker Alias Data Format, Defined Data Format (DD), Selective Automatic Repeat reQuest (SARQ), Re-Synchronize Flag (S), Send sequence number (N(S)), SAP identifier (SAP), Supplementary Flag (SF), Unified Data Transport Format (UDT Format)

Additional notes

• Almost every class/enum supports BitsInterface (de-serialization from on-air bits, serialization to transmission bits)
• Every FEC/CRC implemented supports both calculation, verification and (if possible) also self-correction
• Working with Vocoder and Data/Control Bursts is supported, along with handling rates 1, 1/2 and 3/4
• CRCs interface classes may require appropriate CRC Mask to be provided when generating or verifying
• Through dmr-kaitai handling of ETSI, Hytera and MMDVM/Homebrew UDP data is supported
• To inspect on-wire traffic PcapTool (provided in cli as dmrlib-pcap-tool script) supports PCAP/PCAPNG files with various functions on describing bursts, port/data filtering, data extraction, ...
• Everything is tested, specifically now we have 95% pytest coverage for whole ok-dmrlib codebase