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Weekly Report

21

May

2015

I've had MCPS going for a while now, however the structure I came up with initially made it difficult to pass frames between layers. For example it was up to the top layer to build the frame for sending - a bad way to do things!

The way it works now is that the MAC manages all of the frame memory and the upper layers simply pass in data. This is obviously a much nicer way to do things.

I also spend some time implementing some OS timers (which I am currently modifying to allow the addition of timers from an interrupt context). This allows the code to use callbacks, from a background context, to pass data around in a more event driven manner. While I like the idea of owning my own OS, ubiquiOS is available as an alternative which is likely to be far more stable. I'm still a little undecided but a few more bugs in my OS and I'm sure I'll jump ship. The intention will be to keep an OS abstraction layer so ubiquiOS can be swapped out and replaced as needed.

I've totally restructured the mac into several pieces - MCPS, MLME, coordinator and packet scheduler. The packet scheduler manages queues and timing of sending and receiving packets. MCPS is working, however no CCA is currently done so collisions are possible. I plan to implement beacons before I worry about CCA.

Patrick and I worked together to get 802.15.4 packets into wireshark. Patrick and Richard managed to get the full 6LoWPAN packet decoding going by ignoring the FCS in the MAC packets.