Power efficient indoor radio base station

• US 6,470,193 B1
• Filed: 04/11/1997
• Issued: 10/22/2002
• Est. Priority Date: 04/11/1997
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Stolt, Tomas Nils
• Primary Examiner(s): Vo, Nguyen T.
• Assistant Examiner(s): APPIAH, CHARLES NANA
• Application Number:
  US08/843,006
• Time in Patent Office: 2,020 Days
• Field of Search: 455/522, 455/574, 455/101, 455/103, 455/105, 455/560, 455/561, 455/562, 375/299, 343/797
• US Class Current: 455/562.1
• CPC Class Codes: H01P 1/2131 with combining or separating polarisations
• CPC Class Codes: H04B 1/38 Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A power efficient indoor radio base station for use with wireless cellular telecommunication systems is disclosed. A small unitary package design is achieved by reducing the level of power dissipation, and subsequently, the size of the heat sink required for heat dissipation. In a preferred embodiment of the present invention, a plurality of transmitter signals are combined in a hybrid combiner to generate a pair of output signals. A first output signal is transmitted through a dipole antenna resulting in vertical polarization and a second output signal is transmitted through a horizontal antenna producing horizontal polarization. Further, a phase shift of 90° is introduced between the signals prior to transmission. The resulting simultaneous transmission of the perpendicularly oriented signals yields a substantially circular polarized field in the area of coverage. Power dissipation is reduced by transmitting the horizontal polarized signal because it is converted to useful energy that would otherwise be dissipated in a load resistor.

Claims

1. A radio base station for use with a wireless telecommunication system comprising:

a first transmitter for transmitting a first transmitter signal;

a second transmitter for transmitting a second transmitter signal;

a combiner including at least two input ports coupled to the first transmitter and the second transmitter for combining said first and second transmitter signals, wherein said combiner generates a first output combiner signal and a second output combiner signal having a phase shift of 90°

with respect to each other; and

a first antenna and a second antenna oriented perpendicularly to each other and coupled to the combiner and configured for simultaneously transmitting said first and second output combiner signals through the first antenna and the second antenna respectively such that the emitted signals form a substantially circular polarized field such that said first and second output combiner signals are transmitted with reduced waste energy.

2. A radio base station as recited in claim 1 wherein said combiner is a hybrid combiner.

3. A radio base station as recited in claim 2 wherein a duplex filter is coupled between the hybrid combiner and the at least one antenna.

4. A radio base station as recited in claim 3 wherein said first antenna and second antenna are oriented as a vertical antenna and a horizontal antenna.

5. A radio base station as recited in claim 3 wherein said first antenna and said second antenna is a patch antenna.

6. A radio base station as recited in claim 5 wherein said first and second output combiner signals are emitted from the patch antenna having vertical and horizontal polarized orientations respectively.

7. A radio base station as recited in claim 1 wherein the substantially circular polarized field is elliptically polarized.

8. A radio base station as recited in claim 1 is housed in a weatherproof cabinet for outdoor use.

9. A radio base station as recited in claim 1 wherein additional transmitters are included for increased channel capacity.

10. A method of transmitting signals from a radio base station for use in a cellular telecommunication network, comprising the steps of:

combining a plurality of transmitter output signals with a combiner said combiner including at least two input ports for receiving said plurality of transmitter output signals;

generating first and second combiner output signals using said signals received on said at least two input ports with the combiner, wherein a relative phase shift of 90°

is introduced between the signals; and

transmitting the first and second combiner output signals simultaneously through a first antenna and a second antenna perpendicularly oriented to each other such that one signal is transmitted with vertical polarization and the other signal with horizontal polarization to produce a substantially circular polarized field, wherein the transmission of the first and second combiner signals represents a substantial majority of signal energy from said plurality of transmitter output signals that is ultimately transmitted thereby reducing the amount of power dissipation in the base station.

11. A method as recited in claim 10 wherein said combining is performed with a hybrid combiner.

12. A method as recited in claim 10 wherein said first and second combiner output signals are transmitted through a vertical antenna and a horizontal antenna.

13. A method as recited in claim 10 wherein said first and second antennas are comprised of a patch antenna.

14. A method as recited in claim 13 wherein the radio base station transmits as said substantially circular polarized field an elliptically polarized field by varying at least one of the magnitude and phase of the first and second combiner output signals.

15. A method as recited in claim 10 wherein said power dissipation is removed by a heat sink.