Reducing interference between different communication systems sharing a common wireless transmission medium
View Patent ↗In one embodiment, a first wireless communication system conforms to the IEEE 802.15.3 standard and a second wireless communication system conforms to the IEEE 802.11 standard, where the two systems share a common wireless transmission medium. A combined node functions as both an IEEE 802.15.3 piconet controller and an IEEE 802.11 access point. The combined node transmits IEEE 802.11 control/management frames to inform other IEEE 802.11 nodes about the beginning and end of IEEE 802.11 contention free periods (CFPs), each of which purposely spans an IEEE 802.15.3 CFP and the following superframe beacon. As such, IEEE 802.15.3 nodes have unfettered access to the common wireless transmission medium during IEEE 802.15.3 CFPs, while allowing access by IEEE 802.11 nodes to the medium during IEEE 802.15.3 contention access periods, thereby avoiding destructive interference between IEEE 802.15.3 and IEEE 802.11 communications. Other embodiments are not necessarily limited to these particular wireless LAN standards.
1. A method for reducing interference between two or more communication systems that share a common wireless transmission medium, the method comprising:
transmitting one or more first-standard messages conforming to a first communication standard associated with a first of the communication systems in a first-standard beacon period for the first communication standard, wherein:
the one or more first-standard messages are designed to notify one or more nodes conforming to the first communication standard of (1) the existence of a contention free period (CFP) for the first communication system and (2) the existence of a contention access period (CAP) for the first communication system; and
transmitting one or more second-standard messages conforming to a second communication standard different from the first communication standard, associated with a second of the communication systems in a second-standard beacon period for the second communication standard, wherein:
the one or more second-standard messages are designed to notify one or more nodes conforming to the second communication standard of (1) the existence of a CFP for the second communication system and (2) the existence of a CAP for the second communication system; and
timing of the CFPs and CAPs for the first and second communication systems is coordinated such that;
a CFP for the first communication system spans (1) a CFP for the second communication system and (2) a second-standard beacon period; and
a CAP for the second communication system spans (1) a CAP for the first communication system and (2) a first-standard beacon period.
2. The invention of claim 1 , wherein each node conforming to the first communication standard is allowed to contend for access to the common wireless transmission medium only during the CAPs for the second communication standard.
3. The invention of claim 1 , wherein:
the one or more first-standard messages enable the one or more nodes conforming to the first communication standard to access the common wireless transmission medium during a CAP for the second communication system; and
the one or more first-standard messages disable the one or more nodes conforming to the first communication standard from accessing the common wireless transmission medium during each CFP for the second communication system.
4. The invention of claim 1 , wherein transmitting the one or more first-standard messages comprises transmitting a first message conforming to the first communication standard to notify the one or more nodes conforming to the first communication standard of the beginning of the CFP for the first communication system.
5. The invention of claim 4 , wherein the first message is transmitted at the end of a CAP for the second communication system.
6. The invention of claim 4 , wherein the first message identifies the duration of the CFP for the first communication system.
7. The invention of claim 4 , wherein transmitting the one or more first-standard messages further comprises transmitting a second message conforming to the first communication standard to notify the one or more nodes conforming to the first communication standard of the end of the CFP for the first communication system.
8. The invention of claim 7 , wherein the second message is transmitted at the beginning of a subsequent CAP for the second communication system.
9. The invention of claim 1 , wherein:
the common wireless transmission medium is a wireless channel;
the first communication standard is IEEE 802.11; and
the second communication standard is IEEE 802.15.3.
10. The invention of claim 9 , wherein the first and second messages are transmitted from a node that functions as both an IEEE 802.11 access point and an IEEE 802.15.3 piconet controller.
11. The invention of claim 1 , further comprising transmitting a beacon frame for the second communication system after the end of the CFP for the second communication system.
12. The invention of claim 1 , wherein the one or more messages are transmitted over the common wireless transmission medium.
13. A combined node comprising:
(a) a first transceiver conforming to a first communication standard;
(b) a second transceiver conforming to a second communication standard different from the first communication standard; and
(c) a controller adapted to coordinate operations of the first and second transceivers, wherein:
the first transceiver is part of a first communication system conforming to the first communication standard;
the second transceiver is part of a second communication system conforming to the second communication standard;
the first and second communication systems share a common wireless transmission medium;
the first transceiver is adapted to transmit one or more first-standard messages conforming to the first communication standard, wherein:
the one or more first-standard messages are designed to notify one or more other nodes conforming to the first communication standard of (1) the existence of a contention free period (CFP) for the first communication system and (2) the existence of a contention access period (CAP) for the first communication system;
the second transceiver is adapted to transmit one or more second-standard messages conforming to the second communication standard, wherein:
the one or more second-standard messages are designed to notify one or more other nodes conforming to the second communication standard of (1) the existence of a CFP for the second communication system and (2) the existence of a CAP for the second communication system, CHARACTERIZED IN THAT the controller is adapted to coordinate timing of the CFPs and CAPs for the first and second communication systems such that:
a CFP for the first communication system spans (1) a CFP for the second communication system and (2) a second-standard beacon period; and
a CAP for the second communication system spans (1) a CAP for the first communication system and (2) a first-standard beacon period.
14. The invention of claim 13 , wherein each node conforming to the first communication standard is allowed to contend for access to the common wireless transmission medium only during the CAPs for the second communication standard.
15. The invention of claim 13 , wherein:
the one or more messages enable the one or more nodes conforming to the first communication standard to access the common wireless transmission medium during a contention access period (CAP) for the second communication system; and
the one or more messages disable the one or more nodes conforming to the first communication standard from accessing the common wireless transmission medium during each CFP for the second communication system.
16. The invention of claim 13 , wherein the first transceiver is adapted to transmit a first message conforming to the first communication standard to notify the one or more nodes conforming to the first communication standard of the beginning of the CFP for the first communication system.
17. The invention of claim 16 , wherein the first message is transmitted at the end of a CAP for the second communication system.
18. The invention of claim 16 , wherein the first message identifies the duration of the CFP for the first communication system.
19. The invention of claim 16 , wherein the first transceiver is further adapted to transmit a second message conforming to the first communication standard to notify the one or more nodes conforming to the first communication standard of the end of the CFP for the first communication system.
20. The invention of claim 19 , wherein the second message is transmitted at the beginning of a subsequent CAP for the second communication system.
21. The invention of claim 13 , wherein:
the common wireless transmission medium is a wireless channel;
the first communication standard is IEEE 802.11; and
the second communication standard is IEEE 802.15.3.
22. The invention of claim 21 , wherein:
the first transceiver functions as an IEEE 802.11 access point;
the second transceiver functions as an IEEE 802.15.3 piconet controller.
23. The invention of claim 13 , wherein the second transceiver is adapted to transmit a beacon frame for the second communication system after the end of the CFP for the second communication system.
24. The invention of claim 13 , wherein the one or more messages are transmitted over the common wireless transmission medium.