Node activation with polling channel access

We present a new protocol for collision-free channel access in ad hoc networks called the node activation with polling access (NAPA) protocol. NAPA assumes a time-slotted channel and operates by having each node elect a transmitting node for each time slot based on the identifiers of the nodes in its two-hop neighborhood. In contrast to prior topology-dependent transmission scheduling schemes (e.g., node activation multiple access, or NAMA) in which time slots are wasted when nodes selected for transmission have no packets to send, NAPA complements the election of nodes by means of polling and carrier sensing to use time slots allocated to nodes with no data to send. When a node elected for transmission has no packets to send, it polls one or multiple one-hop neighbors, and each neighbor determines if it can transmit during the time slot based on the identifiers of its two-hop neighbors and sensing of the channel. We show that NAPA supports collision-free transmissions, and compare its performance against NAMA.