Wireless long term evolution radio architecture system and method

• US 8,750,210 B2
• Filed: 07/29/2011
• Issued: 06/10/2014
• Est. Priority Date: 07/29/2011
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Comeau, Adrien Joseph
• Primary Examiner(s): Duong, Frank
• Application Number:
  US13/194,508
• Publication Number:
  US 20130028178A1
• Time in Patent Office: 1,047 Days
• Field of Search: 370/310, 370/311, 370/318, 370328-339, 375/297, 455/13.4, 455/522, 4551271-1273
• US Class Current: 370/328
• CPC Class Codes: H03F 1/34 Negative-feedback-circuit arrangements with or without positive feedback H03F1/02 - H03F1/30, H03F1/38 - H03F1/50, H03F3/50 take precedence ; for rejection of common mode signals H03F3/45479
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H03F 3/68 Combinations of amplifiers, e.g. multi-channel amplifiers for stereophonics power amplifiers using a combination of several semiconductor amplifiers H03F3/211; combinations of amplifiers using coupling networks with distributed constants H03F3/602
• CPC Class Codes: H04B 1/0475 with means for limiting noise, interference or distortion H04B1/0483 takes precedence
• CPC Class Codes: H04B 2001/0433 with linearisation using feedback

Abstract

A method for providing a radio architecture for a long term evolution (LTE) communication system is disclosed. According to one aspect, a radio provides power pooling and direct up-conversion of signals to be transmitted. Power pooling is provided by adjusting the gain and phase of each of a plurality of carrier signals in a digital matrix based on feedback signals received from an analog matrix, such that the output signals are coupled to one or more selected radio output ports. Direct up-conversion is achieved by up-sampling and filtering the carrier signals to be transmitted.

Claims

1. A radio for wireless communication, the radio comprising:

a plurality of radio output ports;

a plurality of power amplifiers;

power pooling circuitry, the power pooling circuitry;

adjusting, by a digital matrix, gains and phases of a plurality of carrier signals based on first feedback signals such that outputs of the plurality of power amplifiers add coherently only at N selected ones of the plurality of radio output ports, N being an integer less than all of the plurality of radio output ports, and destructively interfere at remaining radio output ports; and

selectively directing-output signals from the power amplifiers to N selected ones of the plurality of radio output ports, 1/N of a total output of all the power amplifiers being allocated to each of the N selected radio output ports, N being less than a total number of the plurality of radio output ports, the first feedback signals being based on the output signals; and

a plurality of digital direct up-converters, each of the plurality of digital direct up-converters in communication with a corresponding power amplifier, each of the plurality of digital direct up-converters processing the adjusted carrier signals, the processing including up-sampling the adjusted carrier signals; and

the plurality of power amplifiers amplifying the adjusted up-sampled carrier signals and outputting the amplified adjusted up-sampled carrier signals for transmission using the selected N radio output ports.

2. The radio of claim 1, wherein the digital matrix of the power pooling circuitry is configured to distribute the plurality of carrier signals to the plurality of power amplifiers via the direct up-converters.

3. The radio of claim 1, wherein the power pooling circuitry comprises:

an analog matrix, the analog matrix having a plurality of inputs receiving the amplified up-sampled adjusted carrier signals from a corresponding power amplifier and having a plurality of outputs channeling the amplified up-sampled adjusted carrier signals to the radio output ports.

4. The radio of claim 1, further comprising first couplers arranged to couple the first feedback signals from the directed output signals to the digital matrix of the power pooling circuitry.

5. The radio of claim 4, further comprising an RF multiplexer, the RF multiplexer multiplexing the first feedback signals from the plurality of first couplers.

6. The radio of claim 1, wherein the power pooling circuitry comprises a plurality of linearity devices, each linearity device:

electrically coupled to at least one direct up-converter; and

providing linearity correction to a power amplifier corresponding to the direct up-converter.

7. The radio of claim 6, wherein each of the plurality of power amplifiers has a power amplifier output and the linearity devices receive second feedback signals from a corresponding power amplifier output.

8. The radio of claim 7, further comprising a plurality of second couplers, the plurality of second couplers coupled to the power amplifiers and providing the second feedback signals.

9. The radio of claim 5, wherein the multiplexed first feedback signals are converted to digital signals before coupling the first feedback signals to the power pooling circuitry.

10. The radio of claim 1, further comprising a plurality of digital-to-analog converters DACs, each DAC coupled to a corresponding power amplifier, the plurality of DACs operating at a sample rate that is based on a highest frequency of a carrier signal.

11. The radio of claim 1, wherein the N selected radio output ports are selected based on a desired power per radio output port.

12. The radio of claim 1, further comprising a plurality of antennas, each antenna coupled to a corresponding radio output port.

13. The radio of claim 11, wherein each antenna is directed to a different geographical sector serviced by the radio.

14. A method for processing multiple signals in a transmitter of a wireless communication base station, the transmitter having a plurality of power amplifiers and a plurality of radio output ports, the method comprising:

receiving at a digital matrix a plurality of data-bearing carrier signals;

selecting N radio output ports, N being less than a total number of the plurality of radio output ports;

adjusting gain and phase of the carrier signals in the digital matrix and distributing the adjusted carrier signals to the plurality of power amplifiers, the adjusting based on first feedback signals such that outputs of the power amplifiers add coherently at the N selected radio output ports and destructively interfere at remaining radio output ports, 1/N of a total output power of all the power amplifiers being allocated to each of the N selected radio output ports;

performing digital direct up-conversion of the adjusted carrier signals;

amplifying the up-converted adjusted carrier signals in the power amplifiers;

applying the amplified up-converted adjusted carrier signals to an analog matrix, the analog matrix channeling the applied signals to the radio output ports; and

coupling outputs of the analog matrix to produce the first feedback signals at the digital matrix to enable the digital matrix to adjust the phase and gain of the carrier signals.

15. The method of claim 14, further comprising applying linearity corrections to the adjusted carrier signals to compensate for non-linearity of the power amplifiers.

16. The method of claim 14, wherein the linearity corrections are based on second feedback signals coupled from the power amplifiers.

17. The method of claim 16, wherein the second feedback signals are multiplexed and digitized.

18. The method of claim 14, wherein the first feedback signals are multiplexed and digitized.

19. The method of claim 14, further comprising converting the up-converted signals to analog form prior to input to the power amplifiers.

20. A radio in a wireless communication system, the radio comprising:

a plurality of radio output ports;

a transmitter, the transmitter including;

a digital matrix, the digital matrix adjusting gain and phase of data-bearing carrier signals to be transmitted by the radio, the adjusting based on first feedback signals such that the data-bearing carrier signals to add coherently at N selected radio output ports, N being less than a total number of the plurality of radio output ports, and destructively interfere at remaining radio output ports;

a plurality of digital direct up-converters, the digital direct up-converters receiving the adjusted carrier signals and producing up-converted carrier signals;

a plurality of power amplifiers, the power amplifiers amplifying the up-converted carrier signals, the outputs of the plurality of power amplifiers being channeled to the N selected radio output ports such that 1/N of a total output power of the plurality of output ports is allocated to each of the N selected radio output ports;

an analog matrix, the analog matrix distributing the amplified signals to the radio output ports;

a plurality of couplers, the couplers coupling first feedback signals from the analog matrix to the digital matrix; and

a plurality of antennas, each antenna coupled to a radio output port; and

a receiver, the receiver receiving signals from the antennas during reception.

21. The radio of claim 20, wherein the receiver comprises a direct down-conversion unit, the direct down-conversion unit down-converting the received signals via direct sampling of the received signals.

22. The radio of claim 20, wherein a selected one of the output ports receives power from a plurality of the power amplifiers.

23. The radio of claim 22, wherein the power from the plurality of power amplifiers is combined by the analog matrix.

24. The radio of claim 20, wherein the direct up-converters include digital to analog converters having fixed sample rates selected to up-convert the adjusted carrier signals to a plurality of separate frequency bands.