1. A system (100,130,135;900,930) comprising: - a plurality of networked nodes (1051 - 105N;905) spatially distributed within a monitored area (110;902) and adapted to interact with a mobile entity (115,120;915,920) entering and moving through the area, the plurality of nodes including at least one area entrance node adapted to detect the mobile entity upon entering the monitored area, and a transaction node for accomplishing a transaction with the mobile entity, comprising: - a remote transaction processing center, remote from the plurality of networked nodes and in communication relationship with the nodes through a communication network and a gateway node of the plurality of networked nodes, the transaction processing center for processing (620,625,630,635,640,645) data required for the transaction and for providing the data to the transaction node, wherein the transaction center comprises: a node selection unit (505,510), adapted to dynamically selecting (620,625,630,635,640,645) the transaction node among the plurality of nodes based on an estimation of the speed of movement of the mobile entity and on a knowledge of a spatial distribution of the nodes within the monitored area, said knowledge of a spatial distribution comprising a knowledge of respective position indication that indicates the positions of the sensor nodes, wherein the node selection unit includes: a transaction time estimation unit adapted to estimate (625,630,635) a transaction time required for processing the data; a distance estimation unit adapted to estimate (640,645) a distance covered by the mobile entity within the area in said transaction time, based on an estimated speed of movement of the mobile entity performed upon detecting the mobile entity upon entering the monitored area; and node identification unit adapted to select the transaction node based on the estimated distance. - a plurality of networked nodes (1051 - 105N;905) spatially distributed within a monitored area (110;902) and adapted to interact with a mobile entity (115,120;915,920) entering and moving through the area, the plurality of nodes including at least one area entrance node adapted to detect the mobile entity upon entering the monitored area, and a transaction node for accomplishing a transaction with the mobile entity, comprising: - a remote transaction processing center, remote from the plurality of networked nodes and in communication relationship with the nodes through a communication network and a gateway node of the plurality of networked nodes, the transaction processing center for processing (620,625,630,635,640,645) data required for the transaction and for providing the data to the transaction node, wherein the transaction center comprises: a node selection unit (505,510), adapted to dynamically selecting (620,625,630,635,640,645) the transaction node among the plurality of nodes based on an estimation of the speed of movement of the mobile entity and on a knowledge of a spatial distribution of the nodes within the monitored area, said knowledge of a spatial distribution comprising a knowledge of respective position indication that indicates the positions of the sensor nodes, wherein the node selection unit includes: a transaction time estimation unit adapted to estimate (625,630,635) a transaction time required for processing the data; a distance estimation unit adapted to estimate (640,645) a distance covered by the mobile entity within the area in said transaction time, based on an estimated speed of movement of the mobile entity performed upon detecting the mobile entity upon entering the monitored area; and node identification unit adapted to select the transaction node based on the estimated distance. - a remote transaction processing center, remote from the plurality of networked nodes and in communication relationship with the nodes through a communication network and a gateway node of the plurality of networked nodes, the transaction processing center for processing (620,625,630,635,640,645) data required for the transaction and for providing the data to the transaction node, wherein the transaction center comprises: a node selection unit (505,510), adapted to dynamically selecting (620,625,630,635,640,645) the transaction node among the plurality of nodes based on an estimation of the speed of movement of the mobile entity and on a knowledge of a spatial distribution of the nodes within the monitored area, said knowledge of a spatial distribution comprising a knowledge of respective position indication that indicates the positions of the sensor nodes, wherein the node selection unit includes: a transaction time estimation unit adapted to estimate (625,630,635) a transaction time required for processing the data; a distance estimation unit adapted to estimate (640,645) a distance covered by the mobile entity within the area in said transaction time, based on an estimated speed of movement of the mobile entity performed upon detecting the mobile entity upon entering the monitored area; and node identification unit adapted to select the transaction node based on the estimated distance. a transaction time estimation unit adapted to estimate (625,630,635) a transaction time required for processing the data; a distance estimation unit adapted to estimate (640,645) a distance covered by the mobile entity within the area in said transaction time, based on an estimated speed of movement of the mobile entity performed upon detecting the mobile entity upon entering the monitored area; and node identification unit adapted to select the transaction node based on the estimated distance.