Design and Application of Enhanced Communication Protocols for Wireless Sensor Networks operating in Environmental MonitorinDg

Coexistence Management in Wireless Networks-A Survey

“…• Environment monitoring for air pollution, deforestation, weather, water quality [19], agriculture [20], [21].…”

Efficient MAC Protocols for Wireless Sensor Networks Endowed with Directive Antennas: A Cross-Layer Solution

“…Resorting to the above considerations, a class of MAC protocols, named synchronous transmission asynchronous reception (STAR), particularly suited for a flat network topology, 1 has been derived in [6], taking into account the benefits of both WiseMAC and S-MAC schemes. In particular, it joins the power saving capability, due to the introduction of a duty cycle (S-MAC), together with the communication advantages provided by the offset scheduling (WiseMAC), without an excessive signaling overhead nor requiring a strict synchronization as it happens in the S-MAC protocol.…”

“…where N s is the number of nonoverlapping angular sectors of the transmitter antenna. 6 The value of the phase φ sent is strictly related to the time interval remaining to exit the discovery phase and enter the duty-cycled mode.…”

“…7 In Figure 1 the transition from the discovery to the regime phase occurs when the condition n f = N f d is satisfied, where n f is the 5 Once the communication is logically established with this node, the following hello messages sent to it in a unicast way are able to also reach the other nodes within the same angular sector. 6 If no additional information is provided during the discovery phase, the value of max i {T f ,i } might be estimated by the generic jth node on the basis of its own characteristics (i.e., max i {T f ,i } ≡ T f , j ) and the same is true for min i {T l,i } (i.e., min i {T f ,i } ≡ T f , j ). These values could be further refined upon receiving hello messages from neighbor nodes containing this information.…”

“…This paper aims at filling this gap by proposing a novel MAC layer protocol, namely, directive synchronous transmission asynchronous reception (D-STAR), that broadens the previously introduced STAR MAC approach [6] towards the management of directive antennas. To this end, the crosslayer principle has been adopted to allow the adaptation of physical parameters (as the antenna main lobe pointing) according to the link-to-link communications channel features.…”