CHANNEL DETERMINATION METHOD AND WIRELESS COMMUNICATION APPARATUS

• US 20150003344A1
• Filed: 06/27/2014
• Published: 01/01/2015
• Est. Priority Date: 06/28/2013
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Suwa, Yutaka
• Granted Patent: US 9,479,318 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04L 27/0006 Assessment of spectral gaps suitable for allocating digitally modulated signals, e.g. for carrier allocation in cognitive radio for spectrum sharing between different networks H04W16/14
• CPC Class Codes: H04L 5/0062 Avoidance of ingress interference, e.g. ham radio channels
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks

Abstract

A channel determination method is disclosed that can avoid performance deterioration caused by interference even in a situation in which radio waves from other communication apparatuses including a microwave oven using the same frequency band are mixed. This method detects a predetermined preamble in a received signal when performing carrier sensing while switching between reception frequencies of a receiving section. The method examines, using a counter, how often electric field strength exceeds a predetermined threshold for each channel during the carrier sensing, disables, upon detecting a signal from another 802.11 apparatus, a channel from which the signal is detected and also disables a channel for which the counter shows a count value exceeding the threshold.

Claims

1. A channel determination method in a carrier sensing operation performing a signal receiving operation while switching between reception frequencies of a receiving section, the method comprising:

determining whether or not electric field strength of a received signal exceeds a predetermined threshold;

detecting a predetermined preamble in received data during the carrier sensing operation;

determining to enable or disable a channel in which the predetermined preamble is detected in the received data, in accordance with the electric field strength of the signal;

causing a counter to count up when the electric field strength of the received signal exceeds a predetermined threshold and causing the counter to count down when the electric field strength of the received signal does not exceed the predetermined threshold for each channel during the carrier sensing operation; and

disabling each channel when the count value of the counter of a corresponding one of the channels reaches a predetermined value.

2. The channel determination method according to claim 1, further comprising disabling a channel from which the predetermined preamble is detected, a channel closer to a low-frequency side than the channel, and a channel closer to a high-frequency side than the channel.

3. The channel determination method according to claim 1, further comprising detecting a predetermined preamble in the received data during the carrier sensing operation, determining whether or not electric field strength of the channel in which no predetermined preamble is detected exceeds the predetermined threshold and causing the counter to count up when the electric field strength of the channel exceeds the predetermined threshold.

4. A channel determination method in a carrier sensing operation performing a signal receiving operation while switching between reception frequencies of a receiving section, the method comprising:

detecting a predetermined preamble in received data during the carrier sensing operation;

detecting, when the predetermined preamble is detected, whether or not a received signal is a predetermined beacon;

disabling, when the predetermined preamble is detected in the received data and the received signal is detected to be the predetermined beacon, the channel from which the preamble is detected;

disabling a number of channels adjacent to the channel from which the preamble is detected, the number corresponding to a signal level of the signal from which the preamble is detected;

determining, when the predetermined preamble is not detected in the received data, whether or not electric field strength of the received signal exceeds a predetermined threshold;

causing the counter to count up when the electric field strength of the received signal exceeds the predetermined threshold and causing the counter to count down when the electric field strength of the received signal does not exceed the predetermined threshold for each channel; and

disabling each channel when the count value of the counter of a corresponding one of the channels reaches a predetermined value.

5. A channel determination method in a carrier sensing operation performing a signal receiving operation while switching between reception frequencies of a receiving section, the method comprising:

detecting a predetermined preamble in received data during the carrier sensing operation;

detecting, when the predetermined preamble is detected, whether or not a received signal is a predetermined beacon;

accumulating a CCA value calculated based on information on signal intensity of the received signal relating to the channel from which the preamble is detected and recording the accumulated CCA value as a cumulative CCA value in a recording section;

disabling, when the predetermined preamble is detected in the received data and the received signal is detected to be the predetermined beacon, the channel from which the preamble is detected;

disabling a number of channels adjacent to the channel from which the preamble is detected, the number corresponding to a signal level of the signal from which the preamble is detected; and

determining, based on the cumulative CCA value, whether to enable or disable a channel from which the predetermined preamble is detected in the received data and in which the received signal is not detected to be the predetermined beacon.

6. A wireless communication apparatus comprising:

a receiving section;

a received wave intensity determination section that determines whether or not electric field strength of a signal received by the receiving section exceeds a predetermined threshold;

a counter that counts down when a determination value of the received wave intensity determination section does not exceed the predetermined threshold and counts up when the determination value of the received wave intensity determination section exceeds the predetermined threshold for a channel from which a predetermined preamble is detected in received data obtained from the received signal in a carrier sensing operation; and

a determination section that disables each channel when the count value of the counter of a corresponding one of the channels reaches a predetermined value.

7. The wireless communication apparatus according to claim 6, wherein, when received electric field strength of the signal in the channel from which the preamble is detected exceeds the predetermined threshold, the determination section disables two channels closer to a low-frequency side and two channels closer to a high-frequency side than the detected channel.

8. A wireless communication apparatus comprising:

a transmitting section that transmits a signal;

a receiving section that receives a signal;

a received wave intensity determination section that determines whether or not electric field strength of the signal received by the receiving section exceeds a predetermined threshold during a carrier sensing operation performing a signal receiving operation while switching between reception frequencies of the receiving section;

a demodulation section that demodulates the received signal and outputs the demodulated signal as received data;

a CCA detection section that detects a predetermined preamble in the received data during the carrier sensing operation;

a counter that counts up when the received wave intensity determination section determines that electric field strength of the signal exceeds the predetermined threshold and counts down when the electric field strength of the signal does not exceed the predetermined threshold for each channel during the carrier sensing operation; and

a determination section that disables, when the CCA detection section detects a signal from another apparatus, a channel from which the signal is detected and a channel adjacent to the channel from which the signal is detected, and disables each channel when the count value of the counter of a corresponding one of the channels exceeds a threshold.

9. The wireless communication apparatus according to claim 8, wherein, when the CCA detection section detects a predetermined preamble, the count value of the counter is reset.

10. The wireless communication apparatus according to claim 8, wherein the determination section increases weighting for restricting use of a plurality of channels on a low-frequency side and a high-frequency side of the detected channel in accordance with the received electric field strength of the signal in the channel from which a signal from another apparatus is detected by the CCA detection section.

11. The wireless communication apparatus according to claim 8, wherein, when the received electric field strength of the signal in the channel from which a predetermined preamble is detected by the CCA detection section exceeds the predetermined threshold, the determination section disables two channels closer to a low-frequency side and two channels on a high-frequency side than the detected channel.

12. The wireless communication apparatus according to claim 8, wherein the received wave intensity determination section determines whether or not the electric field strength of the received signal exceeds the predetermined threshold, only when the CCA detection section fails in preamble synchronization of an IEEE802.11 standard packet with the received radio wave.