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) |
| Full/Short Link Control |
✅ |
FLC/SLC PDUs |
| UDP/IPv4 |
✅ |
UDP/IPv4 compressed header/packet |
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), UDP Port Identifier (SPID/DPID), IP Address Identifier (SAID/DAID)
Hytera
| Protocol Name |
Encoding / Decoding |
| Hytera Simple Transport Reliability Protocol (HSTRP) |
✅ |
| Hytera Radio Network Protocol (HRNP) |
✅ |
| Hytera DMR Application Protocol (HDAP) |
✅ |
| Radio Registration Service (RRS) |
✅ |
| Location Protocol (LP) |
✅ |
| Radio Control Protocol (RCP) |
✅ |
| Text Message Protocol (TMP) |
✅ |
- Not all opcodes in all protocols are implemented, however it will fail with descriptive message, which opcode is
missing in particular operation (decoding, description, encoding)
Motorola
| Protocol Name |
Encoding / Decoding |
| Location Request Response Protocol (LRRP) |
✅ |
| Automatic Registration Service (ARS) |
✅ |
| Text Messaging Service (TMS) |
✅ |
- Motorola has MBXML (Motorola Binary XML) which is used to represent LRRP/ARRP documents, ok-dmrlib contains abstract
MBXML implementation with various tools, LRRP implementation tested with both examples and real-world data
- LRRP is supported as
[bytes] <-> [mbxml document(s)] -> [xml representation], currently serialization of xml
document to bytes is not supported
- There are some catches, when you want to serialize MBXML token with common name, look through the test_mbxml and
test_lrrp modules, to see how to select specific (correct) token programatically
Available CLI tools
- dmrlib-pcap-tool - PCAP/PCAPNG traffic description and data extraction
- dmrlib-dmr-burst - Describe full Tier-II burst (33 bytes)
- dmrlib-dmr-header - Describe DMR Data Header
- dmrlib-dmr-ipudp - Describe DMR UDP/IPv4 Compressed data (header + user payload)
- dmrlib-hytera-hstrp - Hytera Simple Transport Protocol
- dmrlib-hytera-hdap - Hytera DMR Application Protocol
- dmrlib-hytera-hrnp - Hytera Radio Network Protocol
- dmrlib-hytera-lp - Hytera Location Protocol
- dmrlib-hytera-rcp - Hytera Radio Control Protocol
- dmrlib-hytera-rrs - Hytera Radio Registration Service
- dmrlib-hytera-tmp - Hytera Text Message Protocol
Additional notes
- Almost every class/enum supports BitsInterface (de-serialization from on-air bits, serialization to transmission bits)
, or for byte-aligned protocols (Hytera, Motorola) BytesInterface (with explicit endianness support)
- 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
- Not everything is probably documented as it should be, but the usage should always be very clear, when you look at
tests of particular component