Methods, systems, and articles of manufacture for performing nutrient trading is described. The global computer network having at least two computerized addressable stations connected to a network, and each of the stations including at least one input and at least one output. The system solves a set of tomographic equations which employ ray theory to establish a relationship between a travel time deviation and the depth residual of a reflector in the depth-offset ray parameter domain. Such calculation operations include determining a corresponding normal vector for each component primitive vertex. The method of an inter-cell load balance of a first base station in a heterogeneous network wireless communication system including the first base station and a second base station includes configuring a first reserve area for the second base station, for the inter-cell load balance and controlling an inter-base station load balance according to the first reserve area.