Asymmetric bandwidth wireless communication techniques

• US 6,498,937 B1
• Filed: 07/14/2000
• Issued: 12/24/2002
• Est. Priority Date: 07/14/2000
• Status: Expired due to Term

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: TRW Inc. (Northrop Grumman Corporation)
• Inventors: Smith, Ronald P.
• Primary Examiner(s): Kincaid, Lester G.
• Assistant Examiner(s): Milord, Marceau
• Application Number:
  US09/616,584
• Time in Patent Office: 893 Days
• Field of Search: 455/522, 455/11.1, 455/127, 455/12.1, 455/13.1, 455/13.4, 455/13.2, 455/572, 455/427, 455/428, 370/315, 370/316, 370/319, 370/396, 370/397, 370/389, 370/395, 370/318, 375/297, 375/305, 375/308, 375/312
• US Class Current: 455/522
• CPC Class Codes: H04B 7/18534 for enhancing link reliablility, e.g. satellites diversity

Abstract

A wireless communication system operates a power amplifier (422) in an earth terminal (400) in a non-saturated mode of operation to transmit communication signals over a communication uplink to a communication satellite (100). The satellite operates a power amplifier (186, 188) in a saturated mode of operation to transmit communication signals over a communication downlink to terminal (400). Operating the amplifiers in the different modes of operation increases efficiency.

Claims

1. In a wireless communication system employing a communication link between a first transmitter/receiver and a second transmitter/receiver, the second transmitter/receiver having a power transmitting disadvantage with respect to the first transmitter receiver, apparatus comprising:

a first power amplifier in said first transmitter/receiver operated in a non-saturated mode of operation during transmission of communication signals to said second transmitter/receiver on said communication link;

a modulator in said second transmitter/receiver operating with constant envelope modulation; and

a second power amplifier in said second transmitter/receiver operated in a saturated mode of operation during transmission of communication signals on said communication link to said first transmitter/receiver.

2. Apparatus, as claimed in claim 1, wherein said first power amplifier is operated in a non-saturated mode of operation comprises a linear mode of operation.

3. Apparatus, as claimed in claim 1, wherein said communication system comprises a satellite communication system and wherein said first transmitter/receiver comprises a satellite communication earth terminal.

4. Apparatus, as claimed in claim 3, wherein said second transmitter/receiver comprises a communication satellite.

5. Apparatus, as claimed in claim 4, wherein said earth terminal comprises a modulator using high order modulation.

6. Apparatus, as claimed in claim 1, wherein said communication system comprises a cellular communication system and wherein said first transmitter/receiver comprises a cellular base station.

7. Apparatus, as claimed in claim 7, wherein said second transmitter/receiver comprises a cellular telephone.

8. In a wireless communication system employing a communication link between a first transmitter/receiver comprising a first power amplifier and a second transmitter/receiver comprising a second power amplifier, the second transmitter/receiver having a power transmitting disadvantage with respect to the first transmitter receiver, said a method of transmitting over the communication link comprising:

generating first communication signals for transmission over said communication link from said first transmitter/receiver to said second transmitter/receiver;

operating said first power amplifier in a non-saturated mode of operation during transmission of said first communication signals to said second transmitter/receiver on said communication link;

generating second communication signals for transmission over said communication link from said second transmitter/receiver to said first transmitter/receiver;

modulating the second communication signals with constant envelope modulation; and

operating said second power amplifier in a saturated mode of operation during transmission of said second communication signals on said communication link to said first transmitter/receiver.

9. A method, as claimed in claim 8, wherein said generating first communication signals comprises generating first satellite communication signals and wherein said operating said first power amplifier in a non-saturated mode of operation comprises operating said first power amplifier in a linear mode of operation.

10. A method, as claimed in claim 9, wherein said generating second communication signal comprises generating second satellite communication signals for transmission to earth.

11. A method, as claimed in claim 10, and further comprising modulating said first satellite communication signals with high order modulation.

12. A method, as claimed in claim 8, wherein said generating first communication signals comprises generating first cellular telephone communication signals for transmission to said second transmitter/receiver.

13. A method, as claimed in claim 12, wherein said generating second communication signals comprises generating cellular telephone communication signals for transmission to said first transmitter/receiver.