BMAC extension: sense a channel without receiving a single preamble packet

[Megh]

How can the receiver determine that the channel is busy by sensing channel without receiving a complete preamble packet? The assumption is that the slotDuration would be less than the size of a preamble packet. If the receiver detects something in the channel, only then it will extend its slotDuration to receive the next preamble.

I am looking for a mac layer solution without modifying the physical layer things, e.g., decider or RSSI. Example code would be much appreciated.

[Thomas Menzel]

From the MAC layer, you can always request the instant PHY state:
phy->getChannelState()
E.g. phy->getChannelState().isIdle();
returns a bool.

[SM]

Thanks Thomas! Fast and great help.

However, i solved from the frame level. That is I sent a small frame and in the receiver, I tried to receive that small frame; then I waited to receive the big frame.