Overlay cell type mobile communication system
First Claim
Patent Images
1. An overlay cell type mobile communication system comprising:
- a macro cell system for forming at least one macro cell having a first diameter in a service area and selecting two carrier frequencies from a plurality of carrier frequencies in the macro cell to perform radio communication based on an FDD scheme; and
a micro cell system for forming and laying a plurality of micro cells having a second diameter smaller than the first diameter of the macro cell on the macro cell;
wherein said micro cell system includes;
carrier selecting means for selecting one carrier frequency from said plurality of carrier frequencies which said macro cell system holds;
channel setting means for setting at least one up channel and down channel for micro cell on the selected carrier frequency; and
means for performing bidirectional radio communication by use of the set up channel and down channels; and
wherein said carrier selecting means includes;
means for dividing said plurality of carrier frequencies which said macro cell system holds into a carrier frequency group for up communication and a carrier frequency group for down communication;
first searching means for selecting one of the carrier frequency groups and searching for a carrier frequency which satisfies a preset condition from a plurality of carrier frequencies included in the selected carrier frequency group; and
second searching means for selecting the other of the carrier freguency groups when a carrier frequency which satisfies the preset condition is not detected by said first searching means and searching for a carrier frequency which satisfies the preset condition from a plurality of carrier frequencies included in the selected carrier frequency group.
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Abstract
When a channel for micro cell is assigned to a mobile station PS1 of a micro cell, one carrier frequency whose reception level is lower than a threshold level is selected from a plurality of up carrier frequencies and down carrier frequencies which a macro cell system holds, an up channel and a down channel for micro cell are set on the selected carrier frequency, the above channels are assigned to the mobile station PS1 of the micro cell to permit radio communication based on the TDD scheme between the mobile station PS1 and a micro cell base station BSb1.
59 Citations
14 Claims
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1. An overlay cell type mobile communication system comprising:
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a macro cell system for forming at least one macro cell having a first diameter in a service area and selecting two carrier frequencies from a plurality of carrier frequencies in the macro cell to perform radio communication based on an FDD scheme; and a micro cell system for forming and laying a plurality of micro cells having a second diameter smaller than the first diameter of the macro cell on the macro cell; wherein said micro cell system includes; carrier selecting means for selecting one carrier frequency from said plurality of carrier frequencies which said macro cell system holds; channel setting means for setting at least one up channel and down channel for micro cell on the selected carrier frequency; and means for performing bidirectional radio communication by use of the set up channel and down channels; and wherein said carrier selecting means includes; means for dividing said plurality of carrier frequencies which said macro cell system holds into a carrier frequency group for up communication and a carrier frequency group for down communication; first searching means for selecting one of the carrier frequency groups and searching for a carrier frequency which satisfies a preset condition from a plurality of carrier frequencies included in the selected carrier frequency group; and second searching means for selecting the other of the carrier freguency groups when a carrier frequency which satisfies the preset condition is not detected by said first searching means and searching for a carrier frequency which satisfies the preset condition from a plurality of carrier frequencies included in the selected carrier frequency group. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A radio telecommunication apparatus for use in a first radio system, wherein the first radio system encompasses a plurality of first areas each having a first base unit which communicates with the radio telecommunication apparatus, the first areas covered by a second area in a second radio system, the radio telecommunication apparatus comprising:
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selecting means for selecting one of frequencies used in the second radio system; setting means for setting a forward and a backward channels in the selected frequency in a time divisional manner; and communicating means for communicating with the first base unit over the set forward and backward channels; and wherein said selecting means includes means for dividing said plurality of frequencies which said second radio system holds into a frequency group for forward communication and a frequency group for backward communication; first searching means for selecting one of the frequency groups and searching for frequency which satisfies a preset condition from a plurality of frequencies included in the selected frequency group; and second searching means for selecting the other of the frequency groups when a frequency which satisfies the preset condition is not detected by said first searching means and searching for a frequency which satisfies the preset condition from a plurality of frequencies included in the selected frequency group. - View Dependent Claims (13, 14)
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Specification