Abstract: A distributed coverage hole recovery process using connectivity information is proposed for wireless sensor networks and other wireless networks. A link is said to exist between two nodes which are sufficiently close. After a un-triangulated hole is detected enclosing by links between N (N>3) active boundary nodes, the distributed hole recovery process activates one or two redundant nodes to recover the hole at each iteration. This process is performed iteratively by each of the active boundary nodes adjacent to the hole independently without any central controller. It requires 2 hops connectivity or neighbor information from each boundary node adjacent to the hole. After each hole recovery iteration, the hole is reduced in size or split into two smaller holes. Then the hole recovery process repeats until the hole is recovered or detected as unrecoverable.

Abstract: In an optical network through which data is transmitted as a stream of bits during successive bit periods by an optical source with a given optical center frequency, to a receiver for detecting a frequency baseband, interferometric noise power, in particular incoherent beat noise power, is minimized by causing a variation in the center frequency of the source such as to cause a redistribution of the incoherent beat noise power from the baseband to higher frequencies, thereby reducing the noise in the baseband.