Scheduling apparatus and method

A scheduling apparatus that generates a plurality of patterns each indicating combinations of a plurality of transmission points forming a radio network system and user equipments for performing radio communication with the plurality of transmission points, and selects an optimum transmission pattern indicating optimum combinations of transmission points and user equipments based on evaluation values of the plurality of patterns by a predetermined search algorithm, the apparatus comprising:

• a convergence pattern selection unit configured to execute a convergence pattern selection, the convergence pattern selection including generating sequentially a plurality of patterns based on designated initial conditions, and selecting, as a convergence pattern, a pattern which has an evaluation value converged to an extreme value, and, as a convergence pattern is selected, repeatedly execute the convergence pattern selection to select another convergence pattern by changing the designated initial conditions;
• and
• a transmission pattern determination unit configured to select, as the optimum transmission pattern, one convergence pattern with the highest evaluation value out of the convergence patterns obtained by the convergence pattern selection unit, wherein the convergence pattern selection unit includes
• an initial condition generation unit configured to generate and output an initial pattern and a seed value as the designated initial conditions,
• a pattern generation unit configured to sequentially generate the plurality of patterns by sequentially changing some of the combinations of the initial pattern output from the initial condition generation unit based on a random number generated from the seed value;
• a pattern evaluation unit configured to sequentially calculate, as each of the plurality of patterns is output from the pattern generation unit, an evaluation value of the pattern output by the respective pattern generation unit,
• a candidate pattern selection unit configured to compare, as the pattern generation unit outputs each of plurality of patterns, the evaluation value of the respective pattern output by the pattern generation unit with the evaluation value of a candidate pattern, to select, as another candidate pattern, the pattern with a higher evaluation value, and sequentially outputs a plurality of candidate patterns, and
• a convergence determination unit configured to select, as the convergence pattern, the latest candidate pattern among the plurality of candidate patterns sequentially output from the candidate pattern selection unit, when detecting a convergence of the evaluation value, to instruct the initial condition generation unit to change one or both of the initial pattern and seed value as the designated initial conditions, to instruct the pattern generation unit to perform initialization and newly start pattern generation, and to instruct the candidate pattern selection unit to initialize the candidate pattern, wherein the convergence of the evaluation value is detected when a change amount calculated between the evaluation values of every two candidate patterns sequentially output at a predetermined convergence determination interval from the candidate pattern selection unit is continuously determined to be smaller than a convergence determination threshold for a number of convergence determination times.