Unused time slot detection and selection in a mobile radio communication system

A mobile radio communication system, comprising:

• a wire network of telephones connected to each other through wire lines;
• a base station connected to said wire network through a wire line;
• a mobile radio communication apparatus connectable to said base station over channels of radio frequencies each having a frame format including a plurality of time slots,
• wherein at least one of said base station and said mobile radio communication apparatus comprises:
• an antenna for transmitting and receiving signals at the radio frequencies;
• unused time slot detecting means coupled to said antenna for detecting unused time slots of a radio frequency by detecting the reception field intensity of said signals received at said antenna;
• time slot selecting means coupled to said unused time slot detecting means for selecting one of the unused time slots;
• and
• channel establishing means for establishing a channel between said mobile radio communication apparatus and said base station in accordance with the radio frequency and the selected time slot.