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Distributed Estimation: preliminary design document {#fleet-wireless-communication-preliminary-design-doc status=ready}

Part 1: Mission and scope

Mission statement

Enable Duckiebots to communicate with each other wirelessly

Motto

BI UNUM IBI OMNES (Where there is one, there is everybody)

Project scope

What is in scope

Communication in a centralized network:

  • Communication between Duckiebots in one Duckietown
  • Define interfaces for communication
  • Performance testing on the communication system
  • One network for one Duckietown
  • TBD: does anything need to be synchronized?

Option 1: Communication in a centralized network with a redundant centralized component (multiple routers)

Option 2: Communication in a de-centralized network (ad-hoc)

System Layout

What is out of scope

  • Shared network communication between Duckietowns in case of a centralized network
  • Communication redundancy with another physical layer
  • Data processing → Message data is just de-serialized and provided to other components

Stakeholders

  • Distributed Estimation
  • Fleet planning
  • Integration Heroes

Part 2: Definition of the problem

Problem statement

Mission = Enable Duckiebots to communicate wirelessly

Problem Statement = Create a communication framework for the Duckiebots

Assumptions

  • Duckiebots can connect to a wifi network
  • Data to be sent is already synchronized ???? TBD
  • Duckiebots leave network when they are out of range or switched off
  • If a Duckiebot is not connected to the communication network, it is not in Duckietown

Approach

Step 0: Define contracts with distributed estimation / fleet planning teams

Step 1: Create the communication framework for the duckiebots and test it on a centralized network

  • Create wifi communication network (physical hardware e.g. wifi router, configuration, etc.)
  • Create a software component that serializes data (create/format datapackets)
  • Create a software component to send and receive messages to/from other duckiebots
  • Integrate Serialization and Messaging software components into THE communication software component (e.g. into a ROS node)
  • Testing:
    • Live visualization of bandwidth (and/or latency, etc. → Network performance measures) of network
    • Live visualization of network topology
    • Are any messages being dropped without arriving at their destination?
    • Etc.

Step 2 (Optional): Test the communication framework using a redundant centralized network

  • Same as step 1, except for the wifi network → redundant centralized network

Step 2 (Optional): Test the communication framework using a de-centralized network

  • Same as step 1, except for the wifi network → AD-HOC network

Functionality-resources trade-offs

Functionality provided

  • Enable duckiebots to join the network.
  • Enable duckiebots to pack data and send it to other duckiebots in the same network.
  • Enable duckiebots to receive and unpack data such that the data can be used in other software modules.
  • Other functionality TBD

Resources required / dependencies / costs

Bandwidth definition:

  • Number of duckiebots in the network
  • Size of the messages
  • Sending frequency
  • Latency in message transmission
  • Extra computation on duckiebots

Performance measurement

  • Visualize the network topology → number of duckies
  • Visualize messages (wireshark) → message size, latency
  • Visualize HW resources → processor, memory, etc.

Part 3: Preliminary design

Modules

Libraries:

  • Serialization
  • Messaging

Integration:

  • Libraries integration into component
  • Communication framework into Duckietown (repository, duckumentation, etc. → contact Integration Heroes)
  • Creation of the WiFi network (centralized vs. decentralized)

Testing:

  • Measuring and visualization of performance metrics

Interfaces

Fleet planning

  • Send data (SLAM, etc.)
  • Distribute data through the network

Distributed Estimation

  • Receive data (local maps built from each Duckiebots)
  • Send data (local maps and/or global map)

Integration Heroes

  • Duckumentation
  • Contract negotiation
  • External libraries (Protocol buffers, ZMQ, etc.)

Preliminary plan of deliverables

Specifications

  • WiFi specs

Software modules

  • Library for Serialization
    • Inputs:
      • Data to be serialized
      • Data to be de-serialized
      • Type definitions for serialization → Contract with distributed-estimation and fleet-planning teams
    • Outputs:
      • Serialized data
      • De-serialized data
    • Functionality:
      • Serialize data
      • De-serialize data
  • Library for Messaging
    • Inputs:
      • Destination
      • Port
      • Type of socket
      • Serialized data
      • Optional: priority
    • Outputs:
      • Serialized data
  • ROS node for messaging
    • Inputs:
      • Messages from ROS topics
      • Messages from other duckiebots
    • Outputs:
      • Messages to ROS topics
      • Messages to other duckiebots

Infrastructure modules

  • Wifi router for Duckietown

    • Network configuration (centralized/decentralized)

  • Testing

    • Visualize the network topology → number of duckies
    • Visualize messages (wireshark) → message size, latency
    • Visualize HW resources → processor, memory, etc.
    • ...

Part 4: Project planning

Part 4: Project planning

Project plan

| Week of | Task | Deliverable | | --- | ---| --- | --- | | 13.11.2017 | * Contract negotiation with the relevant groups|| Write the table down

Task distribution

  • Libraries (incl. Testing): Luca and Antoine
  • ROS node (incl. Testing): Leonie
  • Testing of the framework: Pat and Francesco
  • Redundant centralized network: Pat and Francesco
  • Ad-hoc networking: Leonie, Luca and Francesco

Data collection

TBD --> other groups

Relevant Duckietown resources to investigate

Data collection

What data do you need to collect?

Data annotation

Do you have data that needs to be annotated? What would the annotations be?

Relevant Duckietown resources to investigate

List here Duckietown packages, slides, previous projects that are relevant to your quest

Other relevant resources to investigate

List papers, open source code, software libraries, that could be relevant in your quest.

Risk analysis

What could go wrong?

How to mitigate the risks?