Amplifier architecture for multi-carrier wide-band communications

• US 6,529,715 B1
• Filed: 02/26/1999
• Issued: 03/04/2003
• Est. Priority Date: 02/26/1999
• Status: Expired due to Term

• Current Assignee: Wi-LAN Inc.
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Nitz, William A., Kvinlaug, Hans A., Kitko, Stephen Douglas, Lisco, Richard Joseph
• Primary Examiner(s): Le, Thanh Cong
• Assistant Examiner(s): Harry, Andrew T
• Application Number:
  US09/259,660
• Time in Patent Office: 1,467 Days
• Field of Search: 330/124.R, 330/286, 330/295, 330/149, 330/296, 330/297, 455/101, 455/102, 455/103, 370/339, 375/296, 375/297
• US Class Current: 455/103
• CPC Class Codes: H03F 1/486 with IC amplifier blocks
• CPC Class Codes: H03F 3/211 using a combination of several amplifiers H03F3/60 takes precedence
• CPC Class Codes: H03F 3/24 of transmitter output stages

Abstract

A methodology is provided for processing carriers in a wireless application whereby the outputs of a multiplicity of modulated RF signal sources are combined into a single RF signal stream, that single RF signal stream being thereafter divided among the inputs of another multiplicity of RF power amplifiers. The outputs of that multiplicity of RF power amplifiers are then recombined, filtered and provided as an input to a transmission antenna.

Claims

1. In a wireless communications system operable to transmit modulated carrier signals from a base station to served wireless stations, a method for grouping carriers into one or more subsets of available carriers in said system to effect a reduction in a number of transmitting antennas required for said system, said method comprising the steps of:

selecting a first subset of carriers to include at least two of said available carriers;

combining modulated carrier signals corresponding to said selected subset of carriers into a single RF signal stream;

dividing that single RF signal stream among inputs of a plurality of RF power amplifiers;

causing output signals from said plurality of RF power amplifiers to be combined into one amplified RF signal;

bandpass filtering said one amplified RF signal; and

applying said filtered signal to a transmitting antenna;

selecting at least one additional subset of carriers to include at least one of said available carriers remaining after selection of said first subset of carriers;

iteratively repeating said combining, said dividing, said causing and said filtering steps for said at least one additional subset and applying an output of said filtering step to said transmitting antenna.

2. The method of claim 1 wherein said step of bandpass filtering operates to provide spurious rejection within a filter stopband sufficient to reduce overall spurious emissions of said wireless communications system to a predetermined level.

3. The method of claim 2 wherein said predetermined level to which said overall spurious emissions are reduced is selected to be consistent with system requirements outside occupied signal bandwidths for channelized RF carriers in said wireless communications system.

4. The method of claim 1 wherein said step of bandpass filtering operates to provide a passband/stopband transition region sufficient to provide signal isolation among filters associated with a common transmitting antenna.

5. The method of claim 1 wherein said plurality of RF power amplifiers are established in a cooperative relationship with said bandpass filtering in order to provide amplified output signals meeting in-band spurious emission requirements.

6. The method of claim 1 wherein at least one of said plurality of RF power amplifiers is operative to amplify a single carrier such that an output thereof will meet out-of-band spurious emission requirements without additional filtering.

7. The method of claim 1 wherein said served wireless stations may be fixed or mobile.

8. In a wireless communications system operable to cause modulated RF signals to be transmitted from a base station to served fixed or mobile stations, an architecture for implementation of said RF signal transmission comprising:

a first combiner operable to receive outputs from a plurality of sources of said modulated RF signals and to produce as an output thereof one combined RF signal;

a signal splitter operable to receive said output of said combiner and to provide as an output thereof a plurality of copies of said combined RF signal;

at least one RF amplifier operable to receive as an input ones of said outputs of said signal splitter and to provide as an output an amplified version of the input signal;

a second combiner operative to receive as inputs the outputs of said at least one RF amplifier and to provide as an output thereof one combined amplified RF signal; and

a bandpass filter operative to receive said combined amplified RF signal and to provide as an output thereof a signal to a transmitting antenna;

wherein said RF amplifiers are selected to meet a set of predetermined spurious emission requirements and further wherein said RF amplifiers are established in a cooperative relationship with said bandpass filter in order to provide amplified output signals meeting in-band spurious emission requirements.

9. The wireless system architecture of claim 8 wherein said RF amplifier is enabled to operate over a reduced instantaneous signal bandwidth, thereby achieving a reduction in amplifier complexity.

10. The wireless system architecture of claim 8 including at least two RF amplifiers operable to receive as an input ones of said outputs of said signal splitter, wherein each of said at least two RF amplifiers operates to amplify a common group of signals, said common group of signals occupying an instantaneous bandwidth for which said RF amplifiers are designed to operate.

11. A method for processing RF carriers in a wireless communications system comprising the steps of:

operating on outputs of one or more modulated RF signal sources to combine said outputs into a single RF signal stream;

dividing that single RF signal stream among inputs of a plurality of RF power amplifiers;

causing output signals from said plurality of RF power amplifiers to be combined into one amplified RF signal; and

bandpass filtering said one amplified RF signal;

wherein said RF power amplifiers are established in a cooperative relationship with said bandpass filtering in order to provide amplified output signals meeting in-band spurious emission requirements.

12. The method for processing RF carriers of claim 11 wherein RF signals from said one or more modulated RF signal sources are arranged in a frequency spectrum so as to minimize spurious emissions generated in said system falling into a signal passband of said filter.

13. The method for processing RF carriers of claim 11 wherein a number of RF signal sources operated by said operating step is reduced relative to a number of RF power amplifiers constituting said plurality of RF power amplifiers, thereby providing a higher transmission power for said reduced number of RF signal sources.