Reception Control Method and Wireless Communication Apparatus

• US 20100183099A1
• Filed: 04/24/2008
• Published: 07/22/2010
• Est. Priority Date: 04/24/2007
• Status: Active Grant

• Current Assignee: Kyocera Corporation
• Original Assignee: Kyocera Corporation
• Inventors: Toda, Takeshi, Yamazaki, Tadashi, Okino, Kenta, Nakayama, Taku
• Granted Patent: US 8,467,484 B2
• Time in Patent Office: Days
• US Class Current: 375/340
• CPC Class Codes: H04B 7/0811 during preamble or gap period

Abstract

When receiving a signal from the antenna #1 (initially receiving a signal from an omnidirectional antenna), a guard interval correlator 12 calculates correlation of a guard interval portion of the received signal and an output measuring unit 13 measures a peak output of the guard interval correlator 12. A comparator 14 compares the peak output measured by the output measuring unit 13 with a preset threshold, and when the peak output falls below the preset threshold and outputs an antenna switching control signal to an antenna switch 11, and the antenna switch 11 switches to the antenna #2 having a different directivity.

Claims

1. A reception control method for a wireless communication apparatus having a plurality of antennas, comprising:

a recognition step of recognizing a peak output of a guard interval correlator and/or recognizing a number of samples exceeding a predetermined power value in a predetermined period from output of the guard interval correlator with respect to a received signal; and

an antenna directivity control step of changing directivity of an antenna in the plurality of antennas when the recognized peak output falls below a first predetermined value and/or the number of samples exceeds a second predetermined value.

2. The reception control method according to claim 1, wherein

the plurality of antennas include a first antenna and a second antenna that have directivities different from each other, and

at the antenna directivity control step, the directivity of the antenna in the plurality of antennas is changed by switching from the first antenna to the second antenna when the peak output falls below the first predetermined value and/or the number of samples exceeds the second predetermined value.

3. The reception control method according to claim 1, wherein

the plurality of antennas are directional antennas or include a directional antenna, and

at the antenna directivity control step, the directivity of the antenna in the plurality of antennas is changed by controlling a weighing factor used for weighting a signal received by the directional antenna when the peak output falls below the first predetermined value and/or the number of samples exceeds the second predetermined value.

4. The reception control method according to claim 3, wherein

at the antenna directivity control step, the directivity of the antenna in the plurality of antennas is changed by controlling the weighing factor used for weighting the signal received by the directional antenna to make a half-value angle of directivity of the directional antenna relatively narrow when the peak output falls below the first predetermined value and/or the number of samples exceeds the second predetermined value.

6. The reception control method according to claim 1, further comprising:

a received power measurement step of measuring received power, wherein

at the antenna directivity control step, the directivity of the antenna in the plurality of antennas is changed when the peak output falls below the first predetermined value and/or the number of samples exceeds the second predetermined value and the received power measured at the received power measurement step exceeds a third predetermined value.

7. The reception control method according to claim 2, further comprising:

a received power measurement step for each antenna of measuring received power of each of the plurality of antennas, wherein

at the antenna directivity control step, the directivity of the antenna in the plurality of antennas is changed by switching from the first antenna to the second antenna having relatively high received power based on the measured received power of each antenna when the peak output falls below the first predetermined value and/or the number of samples exceeds the second predetermined value.

8. The reception control method according to claim 2, wherein,

at the recognition step, the peak output of the guard interval correlator is recognized and/or the number of samples exceeding the predetermined power value in the predetermined period is recognized from the output of the guard interval correlator with respect to a received signal of at least the first antenna, and

at the antenna directivity control step, the directivity of the antenna in the plurality of antennas is changed and a symbol timing of a frame of the received signal of the first antenna is changed to a symbol timing of a frame of a received signal of the second antenna by switching from the first antenna to the second antenna when the peak output falls below the first predetermined value and/or the number of samples exceeds the second predetermined value.

9. The reception control method according to claim 2, wherein,

at the recognition step, peak outputs of the guard interval correlator are recognized and/or numbers of samples exceeding the predetermined power value in the predetermined period are recognized respectively from outputs of the guard interval correlator with respect to a received signal of the first antenna and a received signal of the second antenna, respectively, and

at the antenna directivity control step, the directivity of the antenna in the plurality of antennas is changed by switching from the first antenna to the second antenna when the peak output with respect to the first antenna falls below a predetermined value and/or the number of samples exceeds the second predetermined value and the peak output with respect to the second antenna exceeds a predetermined value.

10. The reception control method according to claim 2, wherein,

at the recognition step, peak outputs of the guard interval correlator are recognized and/or numbers of samples exceeding the predetermined power value in the predetermined period are recognized respectively from outputs of the guard interval correlator with respect to a received signal of the first antenna and a received signal of the second antenna, respectively, and

at the antenna directivity control step, the directivity of the antenna in the plurality of antennas is controlled and a symbol timing of a frame of the received signal of the first antenna is changed to a symbol timing of a frame of the received signal of the second antenna by adapting an antenna having a higher peak output as a result of comparison between the recognized peak outputs and/or by adapting an antenna having a smaller number of samples as a result of comparison between the recognized numbers of samples.

11. The reception control method according to claim 1, wherein

the recognition step and the antenna directivity control step are executed when the wireless communication apparatus is initially connected to a wireless communication apparatus of a corresponding party and/or is connected from a wireless communication apparatus of a current corresponding party to a wireless communication apparatus of another corresponding party, and

the execution is stopped when the wireless communication apparatus completes the initial connection to the wireless communication apparatus of the corresponding party and/or completes the change of connection from the wireless communication apparatus of the current corresponding party to the wireless communication apparatus of another corresponding party.

12. The reception control method according to claim 1, further comprising:

a synchronization recognition step of recognizing whether or not synchronization is established in a predetermined period with a base station on a corresponding party side which is a connection target when the wireless communication apparatus is initially connected to a wireless communication apparatus of a corresponding party and/or is connected from a wireless communication apparatus of a current corresponding party to a wireless communication apparatus of another corresponding party, wherein

when it is recognized that synchronization is not established with the base station on the corresponding party side which is the connection target in the predetermined period as a result of the recognition at the synchronization recognition step, the wireless communication apparatus executes the recognition step and the antenna directivity control step, and when it is recognized that synchronization is established with the base station on the corresponding party side which is the connection target in the predetermined period, the wireless communication apparatus stops the execution.

13. The reception control method according to claim 1, further comprising:

a clock jitter amount detection step of measuring a clock jitter amount of a symbol timing of a frame of a received signal, wherein,

when the measured clock jitter amount exceeds a predetermined value, the recognition step and the antenna directivity control step are executed, and

after the steps are executed, if the measured clock jitter amount falls below the predetermined value as a result of the clock jitter amount detection step, the above execution is stopped.

14. The reception control method according to claim 10, wherein the directivity of the antenna in the plurality of antennas is controlled to be omnidirectional when the execution is stopped.

15. The reception control method according to claim 10, wherein,

the directivity of the base station antenna in the plurality of antennas is omnidirectional when the wireless communication apparatus starts initial connection to a wireless communication apparatus of a corresponding party and/or starts connection from a wireless communication apparatus of a current corresponding party to a wireless communication apparatus of another corresponding party, and

the directivity of the antenna in the plurality of antennas after executing the recognition step and the antenna directivity control step is directional.

5. A reception control method for a wireless communication apparatus having a plurality of antennas, wherein the plurality of antennas are directional antennas or include a directional antenna, comprising:

a first recognition step of recognizing a peak output of a guard interval correlator and/or recognizing a number of samples exceeding a predetermined power value in a predetermined period from output of the guard interval correlator with respect to a received signal;

a first antenna directivity control step of changing directivity of the antenna by controlling a weighting factor used for weighting a signal received by the directional antenna when the peak output recognized at the first recognition step falls below a first predetermined value and/or the number of samples exceeds a second predetermined value;

a second recognition step of recognizing a peak output of the guard interval correlator and/or recognizing a number of samples exceeding a predetermined power value in a predetermined period from output of the guard interval correlator with respect to a received signal after the first antenna directivity control step; and

a second antenna directivity control step of changing the directivity of the antenna in the plurality of antennas by controlling the weighting factor to make the peak value exceed the first predetermined value when the peak output recognized by the second recognition step falls below a predetermined value and/or by controlling the weighting factor to make the number of samples fall below the second predetermined value when the number of samples exceeds the second predetermined value.

16. A wireless communication apparatus having a plurality of antennas, comprising:

a guard interval correlator which inputs a signal received by the antenna;

an output measurement unit for measuring output of the guard interval correlator;

a comparison unit for comparing a value relating to the output measured by the output measurement unit and a predetermined value; and

an antenna directivity control unit for controlling directivity of an antenna in the plurality of antennas based on a result of the comparison by the comparison unit.

17. The wireless communication apparatus according to claim 16, wherein,

the value relating to the output indicates a peak output of the guard interval correlator,

the comparison unit compares the peak output with the predetermined value, and

the antenna directivity control unit controls to change the directivity of the antenna when the peak output falls below the predetermined value.

18. The wireless communication apparatus according to claim 16, wherein the predetermined value is a value based on a power value in a predetermined period.

19. The wireless communication apparatus according to claim 18, wherein,

the value relating to the output indicates a number of samples exceeding a predetermined power value in a predetermined period with respect to the output of the guard interval correlator,

the comparison unit compares the number of samples with the predetermined value, and

the antenna directivity control unit controls to change the directivity of the antenna when the number of samples exceeds the predetermined value.