- MappedByteBuffer.hurray()! Programming the Linux Framebuffer in Java & VMFlexArray Explained. See here.
- Internet of #allthethings: Using GNURadio Companion to Interact with an IEEE 802.15.4 Network. See here.
- FreakZ: A BSD-licensed ZigBee stack (for non-commercial purposes)
- Easily modified to communicate to a GNURadio device via UDP (github)
- Note: this stack is not certified.
- a great suite of tools to interact with Software Defined Radio (SDR) transceivers
- GNURadio IEEE 802.15.4 Out Of Tree (OOT) module
- gr-ieee-802_15_4 is available today
- based on work originally from UCLA
- unofficially meets all of the mandatory requirements for the IEEE 802.15.4 PHY layer
- meets some of mandatory requirements for the IEEE 802.15.4 MAC layer
- lacking mandatory MAC features such as
- Beacon Management
- Receive Beacons
- Channel Access Mechanism
- Carrier Sense Multiple Access with Collision Avoidance (CSMA-CA)
- ACK Delivery
- Orphan Scanning
- Store One Transaction
To assist would-be developers in overcoming that hurdle, what I have done is simply used my USRP B200 to record real-world 802.15.4 traffic produced from an EM370 in NodeTest mode. This should easily facilitate offline signal processing using e.g. GNURadio (see File Source block), Matlab, Octave, or any other programming language. The block diagram for doing so is depicted below. I have intentionally made all of my variables directly obvious.
The files are listed and described below:
- simply recording a tone at 2420 MHz in the presence of noise
- note: there is a slight frequency offset which will need to be corrected
- a continuous random stream of valid channel symbols
- a stream containing intermittent & full IEEE 802.15.4 frames
- frames are sent once every 25500 us
A Few Notes About the Current State of IEEE 802.15.4 in GNURadioAll of the open-source PHY implementations assume that Symbol and Timing Recovery (STR) is already performed. This is fine for simulation (depicted below).
However, since we already know the preamble of an IEEE 802.15.4 packet in the 2450 MHz ISM region, we are at liberty to implement a more sophisticated coherent architecture in our receiver. Specifically, due to the known preamble, we may use a Correlate and Sync block.
I will be doing a bit more experimenting in the coming days and will post an update once available.