Felemban et al. investigate the advantage of combining directional antennas and wireless sensor networks (WSNs). Sectored-antenna medium access control (SAMAC), as proposed in the paper, is a protocol that works between layers to facilitate optimum communication options for sensor networks in order to take advantage of sectored antennas. The simulation studies conducted in the course of this research show that the use of SAMAC provides some advantages, like “high energy efficiency and predictable delay performance with graceful degradation in performance with increased load.”

There are some issues with the paper. First, the small graphs used in Figure 20 are not very readable, and the graphs in Figures 21 to 23 lack clarity. Second, the acronyms in Section 11 are not explained (for example, DMAC, BMAC, and TRAMA should have been expanded). In addition, the authors should have paid more attention to the consistency of the notations (for example, they switch between B-MAC and BMAC).

The comparison work presented makes the SAMAC work seem more reliable. That being said, it would be interesting to see comparisons or comments on related work with sectored antennas. The main things analyzed are energy efficiency and predictable, end-to-end delay. Other factors that would assess the performance better could have been considered, including dropped packets or frames, bandwidth, time-slot assignment or duration, and better neighbor discovery.