Mobile communications system and method

A control apparatus for use in a mobile communications system, the mobile communications system including:

• a first system which communicates with a user apparatus in a frequency division duplex (FDD) scheme;
• a second system which communicates with a user apparatus in a scheme which is different from the first system, wherein the second system conducts uplink and downlink communications within a frequency bandwidth between uplink and downlink of the first system,
• a geographical range of the second system is narrower than the geographical range of the first system,
• a downlink transmission power of a base station of the second system is weaker than a downlink transmission power of a base station of the first system,
• the control apparatus is communicably coupled to the base station of the first system and the base station of the second system, and
• the control apparatus variably controls a guard band between the first system and the second system.

A method for use in a mobile communications system, the mobile communications system including:

• a first system which communicates with a user apparatus in a frequency division duplex (FDD) scheme;
• a second system which communicates with a user apparatus in a scheme which is different from the first system;
• and
• a control apparatus which is communicably coupled to the base station of the first system and the base station of the second system, wherein
• the second system conducts uplink and downlink communications within a frequency bandwidth between uplink and downlink of the first system,
• a geographical range of the second system is narrower than the geographical range of the first system,
• a downlink transmission power of a base station of the second system is weaker than a downlink transmission power of a base station of the first system, and
• the control apparatus monitors a communications condition of the second system, and variably controls a guard band between the first system and the second system.