Power saving portable radio communication device with diversity reception

• US 5,566,364 A
• Filed: 01/27/1995
• Issued: 10/15/1996
• Est. Priority Date: 01/31/1994
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Hasegawa, Motoyoshi, Mizoguchi, Tamiyuki
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Nguyen, Lee
• Application Number:
  US08/379,210
• Time in Patent Office: 627 Days
• Field of Search: 455/132, 455/133, 455/134, 455/140, 455/161.3, 455/231, 455/233.1, 455/277.1, 455/277.2, 455/278.1, 455/343, 455/135, 455/136, 455/272, 455/38.3, 375/347
• US Class Current: 455/132
• CPC Class Codes: H04B 7/082 selecting best antenna path
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Electric field intensity of a signal corresponding to a plurality of receivers and received through antennas are converted into direct currents. The converted direct currents thus converted are fed to an electric field level detection circuit. The electric field level detection circuit detects the electric field level on the basis of the direct currents of respective receivers and feeds a detection signal to a control portion. The control portion compares the electric field level corresponding to the direct current value in said controller with a predetermined electric field level to make judgement that the received electric field is a strong electric field and stable. Then, a command is issued to keep one of the receivers, at which the higher electric field level is detected and to turn off other receiver. An electric power source control portion performs switching of the switch portions corresponding to respective of the receivers to supply only one of the receiver from a power source and to block power supply from the power source to other receivers.

Claims

1. A diversity receiver comprising:

first and second receivers having first and second antennas, respectively;

electric field detection means for detecting first and second reception input electric field intensities of said first and second receivers, respectively;

a power supply controller for turning on and off a power supply source to said first and second receivers in accordance with respective first and second power source control signals;

control means for generating said first and second power source control signals, said control means including;

means for generating a monitoring instruction signal for monitoring said first and second reception input electric field intensities;

first comparing means for comparing said first reception input electric field intensity with a predetermined intensity to generate a first higher comparing signal when said first reception input electric field intensity is no less than said predetermined intensity;

second comparing means for comparing said second reception input electric field intensity with said predetermined intensity to generate a second higher comparing signal when said second reception input electric field intensity is no less than said predetermined intensity;

first and second monitoring counters for being set to an initial value in response to turning on said power supply source and for incrementing counting values in response to said first and second higher comparing signals, respectively, and generating respectively the second and first power source control signals for turning off the power supply source to one of said first and said second receivers when each value of said first and second monitoring counters, respectively, becomes a predetermined value.

2. A diversity receiver as set forth in claim 1, wherein said first comparing means generates a first lower comparing signal when said first reception input electric field intensity is lower than said predetermined intensity, and a second comparing means generates said second lower comparing signal when said second reception input electric field intensity is lower than said predetermined intensity, wherein said control means further comprises:

means for generating said first and said second power source control signals for turning on said power supply source in response to said first and second lower comparing signals, respectively; and

wherein said first and second monitoring counters are set to the initial value in response to sad first and second power source control signals for turning on said power supply source, respectively.

3. A diversity receiver as set forth in claim 1, wherein said first and second monitoring counters are reset to "0" in response to said first and second power source control signals for turning off said power supply source, respectively.

4. A diversity receiver as set forth in claim 1, wherein said diversity receiver comprises a portable radio communication device.

5. A diversity receiver as set forth in claim 1, wherein said first comparing means generates a first lower comparing signal when said first reception input electric field intensity is lower than said predetermined intensity.

6. A diversity receiver as set forth in claim 1, wherein said second comparing means generates a second lower comparing signal when said second reception input electric field intensity is lower than said predetermined intensity.

7. A diversity receiver as set forth in claim 1, wherein said control means further comprises means for generating said first and second power source control signals for turning on said power supply source in response to said first and second lower comparing signals, respectively.

8. A diversity receiver as set forth in claim 7, wherein said first and second monitoring counters are set to the initial value in response to said first and second power source control signals for turning on said power supply source, respectively.

9. A diversity receiver as set forth in claim 1, wherein said first and second monitoring counters are reset to a predetermined value in response to said first and second power source control signals for turning off said power supply source, respectively.

10. A diversity receiver as set forth in claim 1, wherein said diversity receiver comprises a radio communication device.

11. A method of controlling a diversity receiver to conserve power, comprising steps of:

supplying power to a first receiver and to a second receiver;

calculating a received signal strength for said first receiver;

comparing said received signal strength for said first receiver to a threshold value;

determining whether said received signal strength for said first receiver is a stable electric field,

if said received signal strength for said first receiver is a stable electric field then turning off the power to said second receiver; and

if said received signal strength for said first receiver is not a stable electric field then;

calculating a received signal strength for said second receiver;

comparing said received signal strength for said second receiver to said threshold value;

determining if said received signal strength for said second receiver is a stable electric field, and

if said received signal strength for said second receiver is a stable electric field then turning off the power to said first receiver;

determining a time period of how long said signal strength is above said threshold value to determine whether a stable electric field exists, wherein said step of determining a time period comprises;

resetting a counter when power is initially supplied to one of said first receiver and said second receiver;

incrementing said counter when said received signal strength is above said threshold value; and

comparing a count of said counter to a predetermined count, and judging that when said count equals said predetermined count, a stable electric field exits.

12. A method of controlling a receiver, comprising steps of:

supplying power to a first receiver and to a second receiver;

calculating a received signal strength for said first receiver;

comparing said received signal strength for said first receiver to a threshold value;

determining whether said received signal strength for said first receiver is a stable field,

if said received signal strength for said first receiver is a stable field, then turning off the power to said second receiver; and

if said received signal strength for said first receiver is not a stable field then;

calculating a received signal strength for said second receiver;

comparing said received signal strength for said second receiver to said threshold value;

determining if said received signal strength for said second receiver is a stable field, and

if said received signal strength for said second receiver is a stable field then turning off the power to said first receiver;

timing how long said signal strength is above said threshold value to determine whether a stable field exists, wherein said step of timing comprises;

resetting a counter when power is initially supplied to one of said first receiver and said second receiver;

incrementing said counter when said received signal strength is above said threshold value; and

comparing a count of said counter to a predetermined count, and wherein when said count equals said predetermined count, a stable field is determined.