Multi-channel RX/TX calibration and local oscillator mismatch mitigation

• US 7,853,216 B1
• Filed: 12/20/2006
• Issued: 12/14/2010
• Est. Priority Date: 12/22/2005
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Atheros Communications Incorporated (Qualcomm, Inc.)
• Inventors: Breslin, Donald, Gilbert, Jeffrey M.
• Primary Examiner(s): Anderson; Matthew D
• Assistant Examiner(s): Tsvey; Gennadiy
• Application Number:
  US11/613,977
• Time in Patent Office: 1,455 Days
• Field of Search: 455/296, 455/446, 455/25, 455/129, 455/33.3, 455/276.1, 455/67.14, 455/67.16, 455/67.11, 455/226.1, 455/101, 455/103, 375/324, 375/326, 375/347, 370/347, 370/337, 370/324, 370/326, 342/368, 342/174, 342/378, 342/442
• US Class Current: 455/67.11
• CPC Class Codes: H01Q 21/29 Combinations of different interacting antenna units for giving a desired directional characteristic H01Q25/00 takes precedence
• CPC Class Codes: H04B 17/11 for calibration

Abstract

A method and system of optimizing transmit beam forming in a multiple radio wireless system is provided. A stimulus signal can be provided to an analog receive input of a device under test (DUT), wherein the DUT includes multiple radios. A receive phase and amplitude can be measured at baseband using the stimulus signal for each radio. At this point, a receive weight and its conjugate can be determined using the receive phases and amplitudes. A calibration vector and its conjugate can also be determined, wherein a product of the receive weight conjugate and the calibration vector conjugate generate a transmit weight. This transmit weight can be applied to transmit signals during the transmit beam forming using the multiple radios.

Claims

1. A method of optimizing transmit beam forming in a multiple radio wireless system, the method comprising:

at a manufacturing test station, providing a stimulus signal to an analog receive input of a device under test (DUT) using a direct wired connection, the DUT including multiple radios;

measuring a receive phase and a receive amplitude at baseband using the stimulus signal for each radio;

determining a receive weight using the receive phases and receive amplitudes;

deriving a receive weight conjugate from the receive weight;

computing a calibration vector;

deriving a calibration vector conjugate;

computing a transmit weight based on a product of the receive weight conjugate and the calibration vector conjugate; and

applying the transmit weight during the transmit beam forming using the multiple radios,

wherein computing the calibration vector and deriving the calibration vector conjugate include comparing a peak power during a range of phase shifts to a power as measured at a stimulus unit providing the stimulus signal.

2. A radio frequency (RF) system comprising:

a first antenna;

a first transmit/receive (T/R) switch connected to the first antenna;

a first low noise amplifier (LNA) connected to the first T/R switch;

first receive components connected to the first LNA;

first transmit components connected to the first T/R switch, wherein the first antenna, first T/R switch, first LNA, first receive components, and first transmit components comprise a first radio;

a second antenna;

a second T/R switch connected to the second antenna;

a second LNA connected to the second T/R switch;

second receive components;

second transmit components connected to the second T/R switch, wherein the second antenna, second T/R switch, second LNA, second receive components, and second transmit components comprise a second radio;

and a shunt switch for selectively connecting the second receive components to outputs of one of the first LNA and the second LNA.