Communications system, communications control apparatus and method, and computer program therefor

• US 20040008641A1
• Filed: 04/04/2003
• Published: 01/15/2004
• Est. Priority Date: 04/15/2002
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Suzuki, Mitsuhiro, Sugaya, Shigeru, Takamura, Kazuhisa
• Granted Patent: US 7,277,412 B2
• Time in Patent Office: Days
• US Class Current: 370/321
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

A communications system sets a network frame period that can be repeatedly used by a plurality of wireless networks in a predetermined time period. A plurality of channel slots for use by each of the wireless networks is prepared in advance in the network frame. A coordinator operating a PAN activates its PAN in an area of a channel slot that is not used by the other coordinator(s). Since each of the wireless networks detects an unused channel slot in the network frame and uses the unused channel slot, the association process is greatly simplified.

Claims

1. A communications system for allowing coexistence of a plurality of networks operated by time division multiple access (TDMA) in the same space, wherein

the communications system sets a network frame that is repeatedly usable by a plurality of wireless networks and prepares in advance a plurality of channel slots for use by each of the wireless networks in the network frame, whereby each of the wireless networks residing in the same space shares an unused channel slot.

2. A communications control apparatus for operating a network by TDMA under a communications environment that allows coexistence of a plurality of networks in the same space, wherein, under the communications environment, a network frame including a plurality of channel slots is set, the communications control apparatus comprising:

network operating means for operating its network using at least one channel slot.

3. A communications control apparatus according to claim 2, further comprising:

network frame detecting means for detecting whether or not a network frame is set in the same space,

wherein, in response to detection of no network frame, the network operating means actively sets a network frame including a plurality of channel slots, operates its network using at least one channel slot, and leaves at least some of the channel slots unused.

4. A communications control apparatus according to claim 3, wherein, in response to detection of an existing network frame, the network operating means operates its network using an unused channel slot in the network frame.

5. A communications control apparatus according to claim 2, wherein the network frame detecting means performs a receive operation for a period greater than or equal to a predetermined network frame period and detects the presence of a network frame in accordance with detection of a transmission signal.

6. A communications control apparatus according to claim 2, further comprising frame managing means for managing the operating state of each channel slot in the network frame.

7. A communications control method for operating a network by TDMA under a communications environment that allows coexistence of a plurality of networks in the same space, wherein, under the communications environment, a network frame including a plurality of channel slots is set, the communications control method comprising:

a network operating step of operating its network using at least one channel slot.

8. A communications control method according to claim 7, further comprising:

a network frame detecting step of detecting whether or not a network frame is set in the same space,

wherein, in the network operating step, in response to detection of no network frame, a network frame including a plurality of channel slots is actively set, its network is operated using at least one channel slot, and at least some of the channel slots are left unused.

9. A communications control method according to claim 8, wherein, in the network operating step, in response to detection of an existing network frame, its network is operated using an unused channel slot in the network frame.

10. A communications control method according to claim 7, wherein, in the network frame detecting step, a reception operation is performed for a period greater than or equal to a predetermined network frame period to detect the presence of a network frame in accordance with detection of a transmission signal.

11. A communications control method according to claim 7, further comprising a frame managing step of managing the operating state of each channel slot in the network frame.

12. A computer program written in a computer-readable format to perform on a computer system a process for operating a network by TDMA under a communications environment that allows coexistence of a plurality of networks in the same space, the computer program comprising:

a network frame detecting step of detecting whether or not a network frame is set in the same space;

a network frame setting step of actively setting a network frame including a plurality of channel slots in response to detection of no network frame;

a first operating slot setting step of operating its network using at least one channel slot while leaving at least some of the channel slots unused; and

a second operating slot setting step of operating, in response to detection of an existing network frame, its network using an unused channel slot in the network frame.