Method and apparatus for coordinating a wireless PAN network and a wireless LAN network
View Patent ↗Devices of a personal area network (PAN) use a wireless medium that is shared with a wireless local area network (WLAN) using power-efficient methods. PAN devices power up as needed to listen for frames. Once a PAN device determines that a frame is not for a PAN device, the PAN device can return to a power down state. In some cases, where a PAN coordinator determines that the wireless medium is congested, setting a PAN device backoff period during which the PAN device can remain in a power down state for an additional time period. Where collisions of PAN device frames are detected, differential backoffs for colliding PAN devices can be assigned. Where the PAN coordinator device needs to send precursor frames into the wireless medium prior to communications with the PAN device, it can arrange for PAN devices to remain powered down during at least a part of the time period during which a precursor frame is being transmitted.
1. A method of communicating using a personal area network (PAN) over a wireless medium that is shared with a wireless local area network (WLAN), between a PAN coordinator device and one or more PAN devices while conserving PAN device power, the method comprising: sending one or more frames from the PAN coordinator device to a PAN device over the wireless medium, wherein the one or more frames are addressed to the PAN device according to a PAN protocol, the PAN protocol having overlap and being only partially compliant with frame formatting layer protocols used for frames of the WLAN; and wherein the PAN protocol that is partially compliant with frame formatting layer protocols used for frames of the WLAN comprises a protocol having WLAN frame formats, or modifications thereof, such that WLAN devices can, upon hearing a PAN protocol frame, understand at least enough of the PAN protocol frame to defer use of a common wireless networking medium; at the PAN device, powering up a receiver to listen for frames;
when the start of a current frame is detected at the PAN device, determining whether the current frame will contain data readable by the PAN device;
if the PAN device determines that the data might be readable, attempting to receive more of the current frame; if the PAN device determines that the current frame will contain data not readable by the PAN device, determining a duration of the current frame from one or more PHY frame parameters of the current frame;
if the PAN device determines that the current frame will contain data not readable by the PAN device, powering down the receiver for a sleep time that depends on the determined duration of the current frame; wherein determining whether the current frame will contain data readable by the PAN device comprises:
a) determining a data rate of the current frame from one or more Physical Layer (PHY) frame parameters of the current frame;
b) determining whether the data rate is one supported by the PAN device; and
c) if the data rate is not one supported by the P AN device, deeming the current frame as one containing data not readable by the PAN device; wherein the sleep time depends on the determined duration of the current frame in that the sleep time is equal to the duration of the current frame less awake time spent since the start of the current frame determining whether to power down.
2. The method of claim 1 , wherein the current frame is a WLANframe.
3. The method of claim 1 , wherein the PAN protocol overlaps with a WLAN protocol such that a PAN protocol compliant device can read parts of a WLAN frame, but is not entirely compatible with the WLAN protocol.
4. The method of claim 3 , wherein determining whether the current frame will contain data readable by the PAN device is determining whether the current frame is a PAN frame or a WLAN frame.
5. A method of communicating using a personal area network (PAN) over a wireless medium that is shared with a wireless local area network (WLAN), between a PAN coordinator device and one or more PAN devices while conserving PAN device power, the method comprising:
sending one or more frames from the PAN coordinator device to a PAN device over the wireless medium, wherein the one or more frames are addressed to the PAN device according to a PAN protocol, the PAN protocol having overlap and being only partially compliant with frame formatting layer protocols used for frames of the WLAN; and
wherein the PAN protocol that is partially compliant with frame formatting layer protocols used for frames of the WLAN comprises a protocol having WLAN frame formats, or modifications thereof, such that WLAN devices can, upon hearing a PAN protocol frame, understand at least enough of the PAN protocol frame to defer use of a common wireless networking medium;
at the PAN device, powering up a receiver to listen for frames;
when the start of a current frame is detected at the PAN device, determining whether the current frame will contain data readable by the PAN device;
if the PAN device determines that the data might be readable, attempting to receive more of the current frame;
if the PAN device determines that the current frame will contain data not readable by the PAN device, determining a duration of the current frame from one or more PHY frame parameters of the current frame; if the PAN device determines that the current frame will contain data not readable by the PAN device, powering down the receiver for a sleep time that depends on the determined duration of the current frame;
wherein determining whether the current frame will contain data readable by the PAN device comprises:
a) determining a data rate of the current frame from one or more Physical Layer (PHY) frame parameters of the current frame;
b) determining whether the data rate is one supported by the PAN device; and
c) if the data rate is not one supported by the PAN device, deeming the current frame as one containing data not readable by the PAN device;
wherein the sleep time depends on the determined duration of the current frame in that the sleep time is approximately equal, within a tolerance, to the duration of the current frame less awake time spent since the start of the current frame determining whether to power down.