LrWpan Mac and Energy

LR-WPAN Energy Model

* LrWpanPhyListener class, Energy model states, Phy state transitions
 - lr-wpan-phy.h
 - lr-wpan-phy.cc 
* Energy Model
 - lr-wpan-radio-energy-model.cc
 - lr-wpan-radio-energy-model.h
* Tests/examples
 - lr-wpan-energy-model-test.cc
 - lr-wpan-data.cc

LR-WPAN ContikiMAC 

* LR-WPAN MAC base class
 - lr-wpan-mac.h
 - lr-wpan-mac.cc 

* 802.15.4 MAC class, extending the LrWpanMac base class
 - lr-wpan-nullmac.h
 - lr-wpan-nullmac.cc

* ContikiMAC model, extending the LrWpanMac base class
 - lr-wpan-contikimac.h
 - lr-wpan-contikimac.cc

* Configured NetDevice use nullmac, can set ContikiMAC using existing SetMac function
 - lr-wpan-net-device.h
 - lr-wpan-net-device.cc 

* Tests/examples
 - lr-wpan-contikimac-test.cc
 - lr-wpan-contikimac-example.cc
3 node scenario: 
Node 1&2 sleep time = 150 ms 
Node 3 sleep time = 125 ms 

First node 1 sends to node 2, Node 3 wakes up first and goes back to sleep after detecting that packet is for another node. Node 2 wakes up and receives packet. 

Then node 1 sends to node 3 and fails as sleep time node 3 > retransmissions done by node 1 

Node 3 broadcasts packet- both node 1 and 2 wake up and receive as per their wake-up schedule 

Node 3 sends packet (without ack bit set) and goes back to sleep immediately