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The modern direction finders (DF) are able to process the frequency band that is much wider than usual signal spectrum. Therefore, as several radio transmitters can be active in the observed frequency range, a further assessment of the active transmitter number as well as their parameters is needed. This additional processing is labeled as spectrum segmentation or preclassification. This paper discusses the possible pre-classification process improvement by using the morphological operations: erosion and dilation. For different types of radio-emissions, the results of conducted analysis of morphological operation application with the use of various structural elements is given. The main contribution of here presented work is the experimental confirmation that the proposed morphological image processing can improve the accuracy of the spectrum segmentation and that this accuracy depends on the choice of structural elements. more...

The cooperative operation of multiple networked sensors, due to redundant radio signal reception, allows considerable gain in AMC performance. We here present a cooperative AMC solution with centralized fusion, with suppression of mismatch reference influence through two-step classification process. A performance analysis is performed under the assumed application conditions for dispersive fading channels. Although latest studies indicated that potential gains reported in idealized application conditions are not feasible in practice, i.e. in the non-idealized application conditions, we here demonstrate that these promised gains can be partly achieved with the suitable two-step classifier construction. more...

The hierarchical routing protocols are considered as a suitable and energy efficient for wireless sensor networks applications that demand frequent and periodic data gathering. Many routing protocols for two-layer (single-hop), tree-layer (dual-hop) and multiple-layer (multi-hop) architectures are developed based on the hierarchical LEACH protocol. In this paper we propose a novel concept for the energy efficient multi-hop routing, with a simple procedure that assigns hierarchical levels to sensor nodes and sets necessary data for routing while the cluster head election process as in LEACH is used. Here proposed multi-hop protocol possess inherent resilience to packet loss due to the non-ideal network connectivity. Performance analysis under ideal and nonideal connectivity conditions showed that here proposed multihop routing protocol outperforms LEACH-based single-hop and dual-hop protocols that were previously proposed with the goal of performance improvement in a case of non-ideal connectivity. more...