Notifying method, and access control device

• US 8,811,204 B2
• Filed: 07/31/2009
• Issued: 08/19/2014
• Est. Priority Date: 07/31/2008
• Status: Active Grant

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Higuchi, Keisuke, Nakaoka, Ken, Mizuguchi, Takao
• Primary Examiner(s): Jiang, Charles C
• Assistant Examiner(s): KAMARA, MOHAMED A
• Application Number:
  US13/056,844
• Publication Number:
  US 20110134788A1
• Time in Patent Office: 1,845 Days
• Field of Search: 370/328, 370/350, 370/442, 370/447, 4554221-460, 455/464
• US Class Current: 370/252
• 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 5/006 Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04L 5/0091 Signaling for the administration of the divided path
• CPC Class Codes: H04W 74/002 Transmission of channel access control information
• CPC Class Codes: H04W 74/0816 with collision avoidance

Abstract

It is specified in a manner such that a frame containing a first period formed by a plurality of slots and a second period having a predetermined length is repeated. A detecting unit detects a slot, which is usable for the communications between a plurality of other terminal apparatuses, from among a plurality of slots in the first period of a frame containing the first period and the second period. A modem unit and an RF unit broadcast information on the detected slot.

Claims

1. An access control apparatus for controlling communications between terminal apparatuses, the access control apparatus comprising:

a detecting unit that is adapted to a scheme where a frame, which contains a first period including a plurality of slots for transmission from terminal apparatuses located in a first area around the access control apparatus and a second period for CSMA/CS communication of terminal apparatuses located in a second area outside the first area, is repeated, the detecting unit being further configured to detect an empty slot having received power smaller than a threshold value, from among the plurality of slots in the first period;

a broadcasting unit configured to broadcast information on the empty slot detected by said detecting unit; and

a determining unit configured to determine a length of the first period in the frame, wherein

the access control apparatus is configured to control the communications between the terminal apparatuses without directly designating for the terminal apparatuses a slot that is used for data communication even when the terminal apparatuses perform data communication,

the determining unit determines the length of the first period such that the larger the number of slots, the longer the first period and the shorter the second period, and

the broadcasting unit broadcasts information on the length determined by the determining unit as well as the information on the empty slot.

2. An access control apparatus according to claim 1, further comprising a measurement unit configured to measure the received power of signal in the communications between a plurality of terminal apparatuses, over at least part of the frame,

wherein said determining unit determines the length of the first period according to the received power measured by said measurement unit.

3. An access control apparatus according to claim 1, wherein said determining unit determines the length of the first period according to the ratio of the number of slots in the first period to the number of slots detected by said detecting unit.

4. An access control apparatus for controlling communications between terminal apparatuses, the access control apparatus comprising:

a detecting unit that is adapted to a scheme where a frame, which contains a plurality of slots for transmission from terminal apparatuses located in an area around the access control apparatus, is repeated, the detecting unit being further configured to detect an empty slot having received power smaller than a threshold value, from among the plurality of slots in the frame;

a broadcasting unit configured to broadcast information on the empty slot detected by said detecting unit; and

a determining unit configured to determine an area determining threshold value for received power, the area determining threshold value being utilized by a terminal apparatus when receiving the information broadcast from the broadcasting unit, wherein

the access control apparatus is configured to control the communications between the terminal apparatuses without directly designating for the terminal apparatuses a slot that is used for data communication even when the terminal apparatuses perform data communication,

said broadcasting unit broadcasts the area determining threshold value determined by the determining unit, as well as the information on the empty slot, and

when received power in the terminal apparatus which receives the information is greater than the area determining threshold value broadcast from the broadcasting unit, the terminal apparatus uses the empty slot.

5. An access control apparatus according to claim 4, wherein the terminal apparatus receiving the information from the broadcasting unit broadcasts at least information on prohibition of transmission so as to at least prohibit transmission to other terminal apparatuses.

6. A broadcasting method employed in an access control apparatus for controlling communications between terminal apparatuses, the method comprising:

detecting, in a scheme where a frame, which contains a first period including a plurality of slots for transmission from terminal apparatuses located in a first area around the access control apparatus and a second period for CSMA/CS communication of terminal apparatuses located in a second area outside the first area, is repeated, an empty slot having received power smaller than a threshold value, from among the plurality of slots in the first period;

broadcasting information on the empty slot detected; and

determining a length of the first period in the frame, wherein

the access control apparatus is configured to control the communications between the terminal apparatuses without directly designating for the terminal apparatuses a slot that is used for data communication even when the terminal apparatuses perform data communication,

the determining determines the length of the first period such that the larger the number of slots, the longer the first period and the shorter the second period, and

the broadcasting broadcasts information on the determined length as well as the information on the empty slot.

7. A broadcasting method employed in an access control apparatus for controlling communications between terminal apparatuses, the method comprising:

detecting, in a scheme where a frame, which contains a plurality of slots for transmission from terminal apparatuses located in an area around the access control apparatus, is repeated, an empty slot having received power smaller than a threshold value, from among the plurality of slots in the frame;

broadcasting information on the empty slot detected; and

determining an area determining threshold value for received power, the area determining threshold value being utilized by a terminal apparatus when receiving the information broadcast from the broadcasting unit, wherein

the access control apparatus is configured to control the communications between the terminal apparatuses without directly designating for the terminal apparatuses a slot that is used for data communication even when the terminal apparatuses perform data communication,

said broadcasting broadcasts the area determining threshold value as well as the information on the empty slot, and

when received power in the terminal apparatus which receives the information is greater than the broadcast area determining threshold value, the terminal apparatus uses the empty slot.