Mobile communications network with expanded carrier capacity and method of expanding base station carrier capacity

1. A base station for a mobile communications system, said base station comprising:

an antenna;

a triplexer connected to one end of a transmission line, an other end of said transmission line being coupled to said antenna, said triplexer separating an uplink signal from a duplexed signal on said transmission line and passing a downlink signal to said duplexed signal, said downlink signal and said uplink signal both comprising a sub-band pair of signals separated by a third sub-band, each sub-band being a sub-band of a given frequency bandwidth;

a duplexer/combiner connected to said triplexer and receiving said uplink signal, said duplexer/combiner providing a first downlink signal to said triplexer in one of said sub-band pair; and

a combiner connected to said duplexer/combiner and said triplexer, said combiner receiving incoming receive signals from said duplexer/combiner and providing a second uplink signal to said triplexer in the other of said sub-band pair.

2. A base station as in claim 1 , wherein a mid sub-band separates said sub-band pair, said mobile communications system base station further comprising:

at least one other antenna; and

another transmission line, one end of said other transmission line being connected to said duplexer/combiner and another end of said other transmission line being coupled to said at least one other antenna, said duplexer/combiner separating a downlink signal from a mid sub-band duplex signal on said other transmission line and passing an uplink signal to said mid sub-band duplex signal.

3. A base station as in claim 2 , wherein carrier capacity for the first said antenna is double carrier capacity for said other antenna.

4. A base station as in claim 3 , further comprising a receive amplifier mounted on each said antenna and coupling said each antenna to a respective said transmission line.

5. A base station as in claim 1 , further comprising:

a second antenna;

a second triplexer connected to one end of a second transmission line, an other end of said second transmission line being coupled to said second antenna, said second triplexer separating a second uplink signal from a second duplex signal on said second transmission line and passing a second downlink signal to said second duplex signal, said second downlink signal and said second uplink signal both comprising a second sub-band pair of signals, one of said second pair being said third sub-band, and one of the first said sub-band pair separating said second sub-band pair, each of said second sub-band pair being a sub-band of said given frequency bandwidth;

said duplexer/combiner being connected to said second triplexer and receiving said second uplink signal, said duplexer/combiner providing a third downlink signal to said second triplexer in one of said second sub-band pair; and

a second combiner connected to said duplexer/combiner and said second triplexer, said second combiner receiving incoming receive signals from said duplexer/combiner and providing a fourth downlink signal to said second triplexer in the other of said second sub-band pair.

6. A base station as in claim 5 , further comprising a receive amplifier mounted on each said antenna and coupling said each antenna to a respective said transmission line.

7. A mobile communications system including at least one base station in a wireless cell, said at least one base station comprising:

an antenna;

a triplexer connected to one end of a transmission line, an other end of said transmission line being coupled to said antenna, said triplexer separating an uplink signal from a duplex signal on said transmission line and passing a downlink signal to said duplex signal, said downlink signal and said uplink signal both comprising a sub-band pair of signals separated by a third sub-band, each sub-band being a sub-band of a given frequency bandwidth;

a duplexer/combiner connected to said triplexer and receiving said uplink signal, said duplexer/combiner providing a first downlink signal to said triplexer in one of said sub-band pair; and

a combiner connected to said duplexer/combiner and said triplexer, said combiner receiving incoming receive signals from said duplexer/combiner and providing a second downlink signal to said triplexer in the other of said sub-band pair.

8. A mobile communications system as in claim 7 , wherein at least one base station is a plurality of base stations, at least one other of said plurality of base stations comprising:

another antenna; and

another said duplexer/combiner connected to one end of another transmission line, an other end of said other transmission line being coupled to said other antenna, said other duplexer/combiner separating an uplink signal from another duplex signal on said other transmission line and passing a downlink signal to said other duplex signal, said downlink signal and said uplink signal both having said given frequency bandwidth.

9. A mobile communications system as in claim 8 , wherein carrier capacity for said antenna in said at least one base station is double carrier capacity for said other antenna in said other base station.

10. A mobile communications system as in claim 7 , wherein said at least one base station further comprises:

another antenna; and

another transmission line, one end of said other transmission line being connected to said duplexer/combiner and another end of said other transmission line being coupled to said other antenna, said other duplexer/combiner separating a mid sub-band uplink signal from another duplex signal on said other transmission line and passing a mid sub-band downlink signal to said other duplex signal, said mid sub-band separating said sub-band pair.

11. A mobile communications system as in claim 10 , wherein carrier capacity for the first said antenna is double carrier capacity for said other antenna.

12. A mobile communications system as in claim 11 , further comprising a receive amplifier mounted on each said antenna and coupling said each antenna to a respective said transmission line.

13. A mobile communications system as in claim 7 , further comprising:

a second antenna;

a second triplexer connected to one end of a second transmission line, an other end of said second transmission line being coupled to said second antenna, said second triplexer separating a second uplink signal from a second duplex signal on said second transmission line and passing a second downlink signal to said second duplex signal, said second downlink signal and said second uplink signal both comprising a second sub-band pair of signals, one of said second pair being said third sub-band and one of the first said sub-band pair separating said second sub-band pair, each of said second sub-band pair being a sub-band of said given frequency bandwidth;

said duplexer/combiner being connected to said second triplexer and receiving said second uplink signal, said duplexer/combiner providing a third downlink signal to said second triplexer in one of said second sub-band pair; and

a second combiner connected to said duplexer/combiner and said second triplexer, said second combiner receiving incoming receive signals from said duplexer/combiner and providing a fourth downlink signal to said second triplexer in the other of said second sub-band pair.

14. A mobile communications system as in claim 13 , wherein at least one base station is a plurality of base stations, at least one other of said plurality of base stations comprising:

at least one other antenna; and

another said duplexer/combiner connected to one end of another transmission line, an other end of said other transmission line being coupled to said other antenna, said other duplexer/combiner separating an uplink signal from another duplex signal from said other transmission line and passing a downlink signal to said other duplex signal, said downlink signal and said uplink signal both having said given frequency bandwidth.

15. A mobile communications system as in claim 14 , wherein carrier capacity for antennas in said at least one base station is double carrier capacity for said other antenna in said other base station.

16. A mobile communications system as in claim 14 , further comprising a receive amplifier mounted on each said antenna and coupling said each antenna to a respective said transmission line.

17. A method of increasing base station carrier capacity in a given bandwidth, said method comprising the steps of:

a) inserting a triplexer between a transmission line and a duplexer/combiner in a base station, said transmission line being coupled to a base station antenna, said triplexer having an uplink connection to, and a first downlink connection from, said duplexer/combiner;

b) attaching a combiner to said triplexer and said duplexer/combiner, said combiner having a second downlink connection from said triplexer and an uplink connection from said duplexer/combiner; and

c) dividing said given bandwidth into sub-bands including a sub-band pair separated by a mid sub-band, said first downlink being in a first of said sub-band pair and said second downlink being in the other of said sub-band pair, said uplink signal including receive signals in both sub-bands of said sub-band pair.

18. A method as in claim 17 , wherein said base station includes a second antenna and said method further comprises coupling carriers in said mid sub-band duplex signal on a second transmission line connected between said duplexer/combiner and said second antenna.

19. A method as in claim 17 , wherein said base station includes a second antenna and before dividing step (c), said method further comprises:

c1) inserting a second triplexer between a second transmission line and said duplexer/combiner, said second transmission line being coupled to said second antenna, said second triplexer having a downlink connection and an uplink connection to said duplexer/combiner; and

c2) attaching a second combiner to said second triplexer and said duplexer/combiner, said second combiner having a downlink connection to said second triplexer and an uplink connection to said duplexer/combiner.

20. A method as in claim 19 , wherein step (c) divides said given bandwidth into at least four sub-bands including two sub-band pairs, each separated by a mid sub-band, one sub-band of each of said two sub-band pairs being said mid sub-band for the other of said two sub-band pairs.

21. A method as in claim 20 , wherein said uplink connection to said second triplexer from said duplexer/combiner and said uplink to said second triplexer from said second combiner are each in one sub-band of the second of said two sub-band pairs and said uplink signal from said second triplexer includes receive signals in both sub-bands of said second of sub-band pair.