Wireless Sensor and Actuator Networks: Algorithms and Protocols for Scalable Coordination and Data Communication

4.10 PHYSICAL LAYER ASPECTS AND CASE STUDIES OF GEOROUTING

Almost all existing literature on geographic routing employs UDG in the communication model. In UDG, two nodes can communicate with each other if and only if their distance is not greater than the common transmission radius. However, as discussed in previous chapters, the UDG model is not realistic since variations of received signal strengths are not considered. It has been pointed out that impact of signal strength fluctuations sometimes is more significant than the impact of node mobility (Stojmenovic et al., 2005). Therefore, reception of a packet is probabilistic. In addition to distance, the received signal strength also depends on other factors, such as environment landscape and transmission medium.

Zorzi and Armaroli (2003) considered advancement as a metric to be used in routing decisions. The advancement provided by a relay node is defined as the difference between the distance of the transmitting node to the intended destination, minus the distance between the relay node and the destination, multiplied by the probability of a successful transmission from the transmitting node to the relay. This idea has been later rediscovered [without citing (Zorzi and Armaroli, 2003)] in several articles, including Kuruvila et al. (2005) (conference version from October 2004), Zuniga Zamalloa et al. (2008) (conference version in November 2004), and Lee et al. (2005).

Kuruvila et al. (2005, 2006) proposed geographic routing ...