Maximum-ratio synthetic transmission diversity device

• US 6,453,150 B1
• Filed: 05/27/1998
• Issued: 09/17/2002
• Est. Priority Date: 05/30/1997
• Status: Expired due to Fees

• Current Assignee: Kyocera Corporation
• Original Assignee: Kyocera Corporation
• Inventors: Yamamoto, Kazuhiro, Iida, Muneo
• Primary Examiner(s): Hunter, Daniel
• Assistant Examiner(s): TRAN, PABLO N
• Application Number:
  US09/085,489
• Time in Patent Office: 1,574 Days
• Field of Search: 455/277.1, 455/277.2, 455/272, 455/273, 455/276.1, 455/278.1, 455/279.1, 455/561, 455/562, 455/13.4, 455/13.3, 455/20, 455/33.4, 455/54.1, 455/12.1, 455/33.1, 455/33.3, 455/25, 342/352, 342/354, 342/368, 342/372, 342/371, 342/373, 343/100, 343/854
• US Class Current: 455/13.3
• CPC Class Codes: H04B 7/0608 Antenna selection according to transmission parameters
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

Antenna elements 20 are arranged at intervals “d” greater than λ/2, e.g., 5λ. A signal received by an antenna element 20 is sent by way of an antenna multiplexer 21 to a receiver 23, where the signal is demodulated. The thus-demodulated signal is sent to a phase-and-power detection section 25, where a phase and power of the signal are detected. On the basis of the result of such detection, a control section 26 calculates the phase and power of a transmission signal. On the basis of the result of the calculation, a transmission signal generation circuit 27 transmits a transmission signal to each of the antenna elements 20 by way of the antenna multiplexer 21.

Claims

1. A base station for a communications system of the Time Division Multiple Access/Time Division Duplex type for transmitting and receiving on a specified wavelength, comprising:

a plurality of land-based antenna elements, all of which are spaced from each other at intervals greater than half of said specified wavelength;

a plurality of antenna couplers, each connected to one of said antenna elements;

a digital signal processor;

a plurality of analog to digital converters each connected to receive an analog input from of said receivers and also connected to provide a digital output to said signal processor; and

a plurality of digital to analog converters, each connected to receive a digital signal from said signal processor and each also connected to provide an analog signal output to one of said transmitters;

wherein a transmission signal to be transmitted from each of said antenna elements has a power level corresponding to the power level of the signal received by said each antenna element, wherein said transmission signal to be transmitted from said each antenna element has a phase corresponding to the phase of the signal received by said each antenna element, and wherein transmission signals transmitted from said plurality of antenna elements generate an omni-directional radiation pattern.

2. The base station of claim 1 wherein each of said antenna elements is spaced approximately 4 or more wavelengths from all other antenna elements.

3. The base station of claim 1 wherein each of said antenna elements is spaced approximately 2.5 or more wavelengths from all other antenna elements.

4. The base station according to claim 1, wherein said signal processor is arranged to compute said phase of said transmission signal based on phase information from said antenna elements via said analog to digital converters and provide said computed phase to each of said antenna elements via said digital to analog converters.

5. A maximum-ratio synthetic diversity device comprising:

a plurality of antenna elements transmitting and receiving at a specified wavelength, said antenna elements being spaced from each other at intervals greater than one half of said specified wavelength; and

a signal processor which detects the phase and the power of the signal received by each of said antenna elements and generates a transmission signal to be transmitted by each of said antenna elements,

wherein a transmission signal to be transmitted from each of said antenna elements has a power level corresponding to a power level of the signal received by said each antenna element, wherein said transmission signal to be transmitted from said each antenna element has a phase corresponding to a phase of the signal received by said each antenna element, and wherein transmission signals transmitted from said plurality of antenna elements generate an omni-directional radiation pattern.

6. The diversity device of claim 5 wherein said antenna elements are spaced at intervals greater than said specified wavelength.

7. The diversity device of claim 5 wherein said intervals are approximately 4-5 of said wavelengths.

8. The diversity device of claim 5 further comprising

a plurality of receivers, each associated with one of said antenna elements and

a plurality of transmitters, each associated with one of said antenna elements.

9. The diversity device of claim 8 wherein said signal processor is a digital circuit comprising a plurality of analog to digital converters, each connecting one of said receivers to said signal processor, and a plurality of digital to analog converters, each connecting one of said transmitters to said signal processor.

10. The diversity device of claim 8 further comprising a plurality of antenna couplers, each of said antenna couplers being connected to one of said antenna elements and said element'"'"'s associated transmitter and receiver.

11. The diversity device of claim 10 wherein each of said antenna couplers is a multiplexer.

12. The diversity device of claim 10 wherein each of said antenna couplers is an electrically controlled switching device.

13. A cellular communication system comprising the diversity device of claim 10 and further comprising at least one two-way mobile communication unit capable of receiving signals on the wavelength transmitted by said transmitters and capable of transmitting signals on the wavelength received by said receivers.

14. The diversity device of claim 5 wherein transmissions are of the Time Division Duplex type.

15. The diversity device of claim 5, wherein transmissions are of the Time Division Multiple Access type.

16. The diversity device of claim 5, wherein each of said antenna elements is spaced approximately 2.5 or more wavelengths from all other antenna elements.