Selection method of cluster head in wireless sensor networks of wireless physical conversion for spectrum sharing

In the physical conversion sensor networks (PhyCSN), the sensor controls the frequency of carrier according to the sensed result and all the nodes inform the sensed results to the fusion center, simultaneously. Since the bandwidth of modulated signal is so narrow, the unused short span of frequency bandwidth is available for the secondary use. However, when the sensing area is wide, the cluster head collects the sensed data in each location. Since the available bandwidth in each cluster is different, the mismatch between the frequency of carrier and the quantization level of sensed data is problem. This paper proposes the mapping algorithm between the frequency of carrier and the quantization level of sensed result and the selection method of cluster head for enlarging the amount of quantization level.