Method of grouping user devices

A grouping method, applied to user devices connected to a base station, comprising:

• by the base station, configuring one or more codes for each of the user devices, wherein each of said one or more codes corresponds to a delay tolerance;
• by the base station, performing a grouping task according to the delay tolerances and a determining result of channel-usage demand corresponding to each of the user devices, so as to form one or more first-type groups and one or more second-type groups, wherein each of said one or more first-type groups corresponds to a first-group delay tolerance, and each of said one or more second-type groups corresponds to a second-group delay tolerance;
• and
• by the base station, performing a selection from user devices in the one or more first-type groups and the one or more second-type groups to form one or more target groups according to the first-group delay tolerances and the second-group delay tolerances,
• wherein the delay tolerances of the one or more first-type groups and the one or more second-type groups are different;
• wherein by the base station, performing the grouping task according to the delay tolerances and the determining result of the channel-usage demand corresponding to each of the user devices, so as to form said one or more first-type groups and said one or more second-type groups comprising:
• by the base station, dividing the user devices into one or more initial first-type group and one or more initial second-type group according to the delay tolerances;
• by the base station, determining whether each of the user devices in each of the initial second-type groups has the channel-usage demand to selectively remove at least one of the user devices from the initial second-type group so as to form said one or more second-type groups;
• and
• by the base station, determining whether each of the user devices in each of the initial first-type groups has the channel-usage demand to selectively remove at least one of the user devices from the initial first-type group so as to form said one or more first-type groups.