Enhancements to VoIP ATM Test Solutions

8th, Mar 2019

Welcome to GL’s another March 2019 Newsletter providing information on our test solutions for smooth transition of services from traditional Air Traffic Management (ATM) to IP based Voice Communications (VoIP).


A traditional Air Traffic Management (ATM) can be migrated to IP based voice communications (VoIP) for providing better and efficient services, and challenges to ensure reliability, and performance. GL offers customized solutions for testing Air Traffic Services Ground Voice Network (AGVN), which includes ability to simulate all the entities, from the radio interfaces to the Controller Working Position (CWP), and remotely monitor the network response with various test scenarios.

The migration to Voice over Internet Protocol (VoIP) poses challenges, which requires a customized test solution, the ATM core network and all its underlying entities (CWP/VCS, GRS, Radio Gateways and Recorders) can be accurately tested for timing, performance, and functionalities. The GL test tools for next generation Air Traffic Management (ATM) offer signaling and traffic simulation per ED-137, monitoring quality of service per ED-138, critical network delay and voice quality measurements.

Our ED-137 and ED-138 Voice over IP Test Tools have been widely welcomed by Global Air Navigation Service Providers and VCS/Radio companies alike, who have found them to be essential tools during development phase, functionality testing, performance testing, Factory Acceptance Test phases, deployment phase and for 'in-the-field' testing.

Below is a typical Air Traffic Management network showing the role of emulators and analyzers. As you can see, we can simulate air-to-ground, ground-to-ground and recorder interfaces as per ED-137 standards. Complete network can be probed using PacketScan™ and analyzed either locally or remotely using NetSurveyorWeb™ applications.

VoIP ATM Test Solutions

GL’s VoIP ATM Test Solution includes Emulators and analyzers deployed across the Air Traffic Management network, which are briefly discussed below -

MAPS™ ED-137 Radio simulates air-to-ground calls by emulating either CWP/VCS or GRS. MAPS™ emulator supports both version B and C of ED-137 volume 1 Radio. Hundreds of CWPs or Radios can be simulated and can generate bulk air-to-ground calls using a single instance/license. Can be used to test functionality and performance of CWP, VCS, GRS and Radio Gateways.

Latest enhancements include -

  • Provides counters for Pilot-Pilot induced SCT and Controller-Pilot induced SCT (synchronous transmission)
  • Supports CLI mode with Python API's
  • Supports sending out of dialog SUBSCRIBE and NOTIFY messages
  • Provides option to configure cause code and reason in BYE and 603 messages
  • Supports both in-dialog and out of dialog Subscription for WG67-KeyIn event
MAPS™  ED-137 Radio

MAPS™ ED-137 Telephone simulates ground-to-ground calls by emulating CWP/VCS. Supports both version B and C of ED-137 volume 2 Telephone. Hundreds of CWPs can be simulated and can generate bulk ground-to-ground calls using a single instance/license. Can be used to test functionality and performance of CWP/VCS.

Latest enhancements include -

  • Enhanced to support ED137C version
  • Supports OPTIONS PING feature
  • Supports both Attended and Unattended call transfer
  • Supports sending out of dialog SUBSCRIBE and NOTIFY messages
MAPS™  ED-137 Telephone

MAPS™ ED-137 Recorder is used to simulate Recorder interface at VCS, GRS and Recorder server as per version B of ED-137 volume 4 Recorder. MAPS™ emulator can be configured as either CWP or GRS or Recorder to simulate recorder interface at that node. Hundreds of CWP/GRS/Recorders can be simulated.

Latest enhancements include -
  • Supports Embedded (interleaved) Binary Data transport method for media transmission
  • Provides options to simulate call scenarios such as Voting, Simultaneous SQL, Call Hold, Call Intrusion and Call Transfe
MAPS™  ED-137 Recorder

PacketScan™ is an all-IP Network Monitoring software, which offers powerful features to capture and monitor A-G and G-G calls in the ATM network.  The application can capture, segregate, monitor and collect statistics such as Packet loss, delay, jitter and MOS scores on all the captured calls. It can also act as a probe in the network and send Call Detailed Records to a centralized database.

Latest enhancements include -
  • Supports analysis of Air to Ground and Ground to Ground Calls
  • For AG calls, calculates voice quality statistics like MOS, Packet loss, delay and jitter for every PTT and Squelch cycle
  • For GG calls, voice quality metrics are calculated in chunks to provide more accurate results throughout the call duration
  • Call graph is updated with events like PTT on/off, Squelch on/off, PTT Summation, PTT Mute, SCT on/off etc as and when they occur on the call
  • Aggregated call statistics like Total AG and GG calls, Active calls, completed calls and Failed call counts are provided
  • Detects and provides count for Pilot-Pilot induced SCT and Controller-Pilot induced SCT (synchronous transmission)
  • Provides aggregated and per call PTT and Squelch cycle count
  • Sends Call Detailed Records for each call and for each event on the call

NetSurveyorWeb™ Lite is a web-based client application, which facilitates real-time data display, navigate through historical records (9 GB of CDR storage), filter the collected VoIP traffic summary, and graphically analyze the call volume, MOS (Mean Opinion Score), Packet loss, failed calls, completed calls, Post Dial Delay, and more. NetSurveyorWeb™ Lite version can be deployed on the Probe (PacketScan™) system with limited database on the same system.

Latest enhancements include -
  • Supports analysis of Air to Ground and Ground to Ground Calls
  • Provides quick CDRs (Call Detailed Records) for AG calls, GG calls, Good and low MOS score calls etc
  • Call Detail view provides events summary and voice quality for each PTT and Squelch cycles
  • Provides call graph with all events on the call like PTT on/off, Squelch on/off etc listed
  • Provides important ED-137 reports for Total AG and GG calls, MOS score, Packet loss, Failed calls over a period
NetSurveyorWeb™  Lite

TM-ATM Solution (Timing Measurements in Air Traffic Management) is a custom suite of test tools designed to accurately measure various types of delay occurrence in signaling and voice transmission. It includes all necessary hardware and software to identify, capture, time stamp, and correlate events at Analog, TDM and IP interfaces.

GL's Servers in TM-ATM Test Suite are -
  • MAPS™ Administrator (TM-ATM Client) a centralized component which controls various servers in the TM-ATM client server model
  • MAPSTM ED-137 Radio emulator to generate Air-to-Ground calls and simulate PTT and other radio signals
  • Voice Quality Testing (VQT) software performs voice quality assessment using industry standard ITU algorithms (PESQ and POLQA) across the ATM network
  • Packet Analyzer filters packets of interest and generates output TTL signal pulses for every filter match
  • Audio Analyzer can simulate PTT, inject and record analog signals at CWP, Radio, and VoIP gateway interfaces and generate TTL triggers for PTT on/off and for audio transmit and receive
  • Packetizer or Discrete Signal Logger monitors the TTL output from the Audio Analyzer and generates a corresponding IP packet
  • Event Data Logger at the centralized location receives event packets, timestamp and updates the events to the MAPS™ Administrator

Latest enhancements include -

  • Supports end-to-end Voice Quality (POLQA) measurement using industry standard ITU algorithms (PESQ and POLQA)
  • Detection of voice burst on the IP network and end-to-end voice delay measurement

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