TDMA-TDD/FDD radio communication system and channel selection method and apparatus for such a system
First Claim
1. A TDMA radio communication system combining time and frequency division duplex, said system comprising:
- a first base station having a first radio coverage area and transmitting in first down link frames on a first carrier frequency and receiving in first uplink frames, which have no time overlap with said first downlink frames, on a second, different carrier frequency;
a second base station having a second radio coverage area and transmitting in second down link frames on said first carrier frequency and receiving in second uplink frames, which have no time overlap with said second downlink frames, on said second carrier frequency, said second radio coverage area partially overlapping said first radio coverage area, and said second base station being geographically separated from said first base station in order to prevent transmissions from either base station disturbing reception on radio terminals on the other base station;
a network controller synchronizing transmission from said first and second base stations and offsetting transmission from said second base station by one downlink frame relative to transmission from said first base station, wherein mobile radio terminals monitor channel quality and offset on downlink frames from both base stations for performing mobile radio terminal controlled dynamic channel selection in connection with call setup and handover.
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Accused Products
Abstract
A TDMA radio communication system combines time and frequency division duplex. It includes a first base station transmitting in first downlink frames on a first carrier frequency in a first frequency band and receiving in first uplink frames, which have no time overlap with the first downlink frames, on a second carrier frequency in a second frequency band, which has no frequency overlap with the first frequency band. The system also includes a second base station, which has partially overlapping radio coverage area with the first base station, but is geographically separated from the first base station in order to avoid transmission from one base station disturbing reception from radio terminals on the other base station. The second base station transmits in second downlink frames on the first carrier frequency and receives in second uplink frames, which have no time overlap with the second downlink frames, on the second carrier frequency. The first and second downlink frames are offset to have no time overlap. A network controller synchronizes transmission from the first and second base stations.
88 Citations
16 Claims
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1. A TDMA radio communication system combining time and frequency division duplex, said system comprising:
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a first base station having a first radio coverage area and transmitting in first down link frames on a first carrier frequency and receiving in first uplink frames, which have no time overlap with said first downlink frames, on a second, different carrier frequency;
a second base station having a second radio coverage area and transmitting in second down link frames on said first carrier frequency and receiving in second uplink frames, which have no time overlap with said second downlink frames, on said second carrier frequency, said second radio coverage area partially overlapping said first radio coverage area, and said second base station being geographically separated from said first base station in order to prevent transmissions from either base station disturbing reception on radio terminals on the other base station;
a network controller synchronizing transmission from said first and second base stations and offsetting transmission from said second base station by one downlink frame relative to transmission from said first base station, wherein mobile radio terminals monitor channel quality and offset on downlink frames from both base stations for performing mobile radio terminal controlled dynamic channel selection in connection with call setup and handover. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A TDMA radio communication system combining time and frequency division duplex said system including
a first base station transmitting in first downlink frames on a first carrier frequency and receiving in first uplink frames, which have no time overlap with said first downlink frames, on a second, different carrier frequency, a second base station transmitting in second down link frames on said second carrier frequency and receiving in second uplink frames, which have no time overlap with said second down link frames, on said first carrier frequency; - and
a network controller synchronizing and time aligning transmission from said first and second base stations. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A mobile radio terminal in a TDMA radio communication system combining time and frequency division duplex, said system including
a first base station having a first radio coverage area and transmitting in first downlink frames on a first carrier frequency and receiving in first uplink frames, which have no time overlap with said first downlink frames, on a second, different carrier frequency: -
a second base station having a second radio coverage area and transmitting in second downlink frames on said first carrier frequency and receiving in second uplink frames, which have no time overlap with said second down link frames, on said second carrier frequency, said second radio coverage area partially overlapping said first radio coverage area, and said second base station being geographically separated from said first base station in order to avoid that transmission from one base station disturbs reception from radio terminals on the other base station; and
a network controller synchronizing transmission from said first and second base stations and offsetting transmission from said second base station by one downlink frame relative to transmission from said first base station, said mobile radio terminal including a control unit for monitoring channel quality and offset on down link frames from both base stations for performing mobile radio terminal controlled dynamic channel selection in connection with call setup and handover.
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15. A mobile radio terminal in a TDMA radio communication system combining time and frequency division duplex, said system including
a first base station transmitting in first down link frames on a first carrier frequency and receiving in first uplink frames, which have no time overlap with said first downlink frames, on a second, different carrier frequency: -
a second base station transmitting in second down link frames on said second carrier frequency and receiving in second uplink frames, which have no time overlap with said second downlink frames, on said first carrier frequency; and
a network controller synchronizing and time aligning transmission from said first and second base stations, said mobile radio terminal including a control unit for monitoring channel quality on downlink frames from both base stations for performing mobile radio terminal controlled dynamic channel selection in connection with call setup and handover.
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16. A dynamic channel selection method in a mobile radio terminal in a TDMA radio communication system combining time and frequency division duplex, said system including
a first base station transmitting in first downlink frames on a first carrier frequency and receiving in first up link frames, which have no time overlap with said first downlink frames, on a second, different carrier frequency: -
a second base station transmitting in second downlink frames on said second carrier frequency and receiving in second uplink frames, which have no time overlap with said second downlink frames, on said first carrier frequency; and
a network controller synchronizing and time aligning transmission from said first and second base stations, said dynamic channel selection method including the steps monitoring channel quality on down link frames from both base stations;
selecting a channel based on said channel quality; and
locking said mobile radio terminal to said selected channel.
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Specification