Pre-computation based selective probing (PCSP) scheme with imprecise state information

In this paper, we extend the previously presented QoS routing scheme called pre-computation based selective probing (PCSP) to the practical environment where the state information available for the routing decision is not precise. This extended PCSP algorithm pre-computes the QoS variations as well as the cost and QoS metrics of the least-cost and best-quality paths, taking into account the impreciseness of state information. The pre-computed information enables to strictly limit the set of neighbor nodes involved in the probing process, thereby reducing the message complexity without sacrificing cost optimality. This extended PCSP scheme encompasses the original PCSP scheme as a special case where the variation of state information reduces to zero. Computer simulation reveals that the extended PCSP scheme maintains low message complexity and high success ratio with guaranteed optimal search