Low power protocol for wireless terminal peer-to-peer communications
View Patent ↗A Wireless Local Area Network (WLAN) system in which wireless terminals each operate upon battery power. One of the wireless terminals acts as a Master to coordinate the transmission and receptions of the Slaves so as to reduce the power consumed by all of the devices. The Slaves operate according to a power up and power down sequence to conserve battery power. Further, the terminals may alternate between being Slaves and being the Master to equalize battery consumption of the wireless terminals.
1. A method for managing peer-to-peer communications in a Wireless Local Area Network (WLAN) having a plurality of wireless terminals including a transmitter and a receiver, one of the plurality of wireless terminals acts as a master at any time and remaining ones of the plurality of wireless terminals acting as slaves at any time to alternate mastering duties among the plurality of wireless terminals, the method comprising:
communicating according to a frame cycle including a beaconing period and a broadcast data period;
during the beaconing period, the one wireless terminal of the plurality of terminals acting as the master transmitting a beacon and each of the remaining wireless terminals of the plurality of wireless terminals acting as the remaining ones of the plurality of wireless terminals listening for the beacon;
during the broadcast data period, the one wireless terminal of the plurality of terminals acting as the master broadcasting data and each of the remaining ones of the plurality of wireless terminals listening for the broadcast data; and
alternating mastering duties among the plurality of wireless terminals according to a round-robin mastering cycle, the round-robin mastering cycle including a plurality of frame cycles, wherein another one of the plurality of wireless terminals acting as a master during each frame cycle of the plurality of wireless terminals and the remaining ones of the plurality of wireless terminals acting as the slaves during the each frame cycle of the plurality of wireless terminals.
2. The method of claim 1 , wherein none of plurality of wireless terminals acts as the master for consecutive frame cycles of the round-robin mastering cycle.
3. The method of claim 1 , wherein none of plurality of wireless terminals acts as the master for more than one frame cycle of the plurality of frame cycles of the round-robin mastering cycle.
4. The method of claim 1 , wherein one of the plurality of wireless terminals acts as the master for more than one consecutive frame cycle of the plurality of frame cycles of the round-robin mastering cycle.
5. The method of claim 1 , wherein during both the beaconing period and the broadcast data period, at least one of the remaining ones of the plurality of wireless terminals acting as the slaves powers down its respective transmitter.
6. The method of claim 1 , further comprising:
during the beaconing period, a remaining one of the plurality of wireless terminals acting as a slave determining that it has been assigned a polled data period that immediately follows the broadcast data period;
the remaining one of the plurality of wireless terminals acting as the slave powering down its transmitter during the beaconing period; and
the remaining one of the plurality of wireless terminals acting as the Slave powering up its transmitter during a polled data period immediately following the broadcast data period.
7. The method of claim 1 , further comprising:
during the beaconing period, a remaining one of the plurality of wireless terminals acting as a slave determining that it has been assigned a polled data period that does not immediately follow the broadcast data period;
the remaining one of the plurality of wireless terminals acting as the slave powering down its transmitter during the beaconing period;
the remaining one of the plurality of wireless terminals acting as the slave powering down its receiver during a polled data period immediately following the broadcast data period; and
the remaining one of the plurality of wireless terminals acting as the slave powering up its transmitter and its receiver during its assigned polled data period.
8. The method of claim 1 , further comprising, during the plurality of polled data periods, the remaining plurality of wireless terminals acting as the Slaves powering down their transmitters and receivers during unassigned polled data periods.
9. A wireless terminal for peer-to-peer communications in a Wireless Local Area Network (WLAN) having a plurality of wireless terminals, the wireless terminal comprising:
a processor;
a radio frequency unit coupled to the processing circuitry that supports wireless data transmission, the radio frequency unit including a transmitter and a receiver;
memory coupled to the processor, wherein the memory stores operational instructions that cause the processor to:
during a frame cycle of a plurality of frame cycles, configure the wireless terminal to act as a slave, wherein one of the plurality of wireless terminals will act as a master undertaking mastering duties among the plurality of wireless terminals, and remaining ones of the plurality of wireless terminals will act as slaves;
when the wireless terminal acts as a master during a beaconing period of the frame cycle, transmit a beacon in which each of the remaining ones of the plurality of wireless terminals operate to listen for the beacon;
during a broadcast data period of the frame cycle, broadcast data in which each of the remaining ones of the plurality of wireless terminals operate to listen for the broadcast data; and
alternate mastering duties according to a round-robin mastering cycle, wherein by altering mastering duties, the wireless terminal acts the master during at least one frame cycle and acts the slave during other frame cycles.
10. The wireless terminal of claim 9 , wherein the wireless terminal does not act as the master for consecutive frame cycles of the round-robin mastering cycle.
11. The wireless terminal of claim 9 , wherein the wireless terminal does not act as the master for more than one frame cycle of the plurality of frame cycles of the round-robin mastering cycle.
12. The wireless terminal of claim 9 , wherein the wireless terminal acts as the master for more than one consecutive frame cycle of a plurality of frame cycles of the round-robin mastering cycle.
13. The wireless terminal of claim 9 , wherein, when the wireless terminal acts as a Slave, the memory further stores operational instructions that cause the processor to:
during both the beaconing period and the broadcast data period, power down its transmitter.
14. The wireless terminal of claim 9 , wherein, when the wireless terminal acts as a Slave, the memory further stores operational instructions that cause the processor to:
power up its receiver after a contention period of the cycle of plurality of cycles in anticipation of the next beaconing period.
15. The wireless terminal of claim 9 , wherein, when the wireless terminal acts as a master, the memory further stores operational instructions that cause the processor to:
power down its transmitter during a contention period of the frame cycle.