  Recently designed cross-layer contention based synchronous MAC protocols like
the PRMAC protocol, for wireless sensor networks (WSNs) enable a node to
schedule multi-hop transmission of multiple data packets in a cycle. However,
these systems accommodate both the request-to-send data process and the
confirmation-to-send data process in the same data transmission scheduling
window (i.e. data window). This reduces the length of the multi-hop flow setup
in the data window. In a multi-hop scenario, this degrades both the packet
delivery ratio (PDR) and the end-to-end transmission delay (E2ETD). In this
paper, we propose a cross-layer contention based synchronous MAC protocol,
which accommodates the request-to-send data process in the data window and the
confirmation-to-send data process in the sleep window for increased efficiency.
We evaluate our proposed protocol through ns-2.35 simulations and compare its
performance with the PRMAC protocol. Results suggest that in multi-hop
scenario, proposed protocol outperforms PRMAC both in terms of the E2ETD and
the packet delivery ratio (PDR).
