Adaptive power and data rate control for ad-hoc mobile wireless systems
First Claim
1. A method for controlling transmit power, comprising:
- receiving one of a hello request to send (HRTS) signal, broadcast request to send (BRTS) signal and packet request to send (PRTS) signal;
computing a signal to noise ratio (SNR) for the one of the HRTS, BRTS, and PRTS signal;
computing a transmit power for a probing RTS (PrRTS) signal based at least in part on the SNR of the one of the HRTS, BRTS and PRTS signal, and thereafter transmitting both a request to send (RTS) signal and the PrRTS signal;
receiving a clear to send (CTS) signal in response to the RTS and PrRTS signals, the CTS signal including a SNR for the PrRTS signal;
computing a SNR correction factor based at least in part on the SNR for the PrRTS signal; and
transmitting a data packet at a power level that is computed based at least in part on the SNR correction factor.
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0 Petitions
Accused Products
Abstract
A method for controlling transmit power of a node in wireless network, such as, e.g., an ad-hoc wireless network operating in accordance with a carrier sense multiple access (CSMA) protocol and where asymmetrical radio links may exist. During a request to send (RTS) and clear to send (CTS) exchange between a first node and a second node, both a request to send (RTS) packet and a probing request to send (PrRTS) packet are transmitted from the first node to the second node. The transmit power and data rate of the PrRTS packet may be different from the transmit power and data rate of the RTS packet. In response, the second node returns a CTS packet that includes a signal to noise ratio (SNR) for both the RTS packet and the PrRTS packet. A correction factor for data transmit power is then computed based in part on both the SNR for the RTS and the SNR for the PrRTS, and a data packet is thereafter transmitted at a power level that has been modified in accordance with the correction factor. The correction factor may further aid the estimation of the signal-to-noise-and-interference ratio (S/(N+I)) at a receiving node, which enables a sending node either to overcome the interference by adjusting the transmit power or avoid the interference by not accessing the channel until it hears the node again.
53 Citations
36 Claims
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1. A method for controlling transmit power, comprising:
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receiving one of a hello request to send (HRTS) signal, broadcast request to send (BRTS) signal and packet request to send (PRTS) signal; computing a signal to noise ratio (SNR) for the one of the HRTS, BRTS, and PRTS signal; computing a transmit power for a probing RTS (PrRTS) signal based at least in part on the SNR of the one of the HRTS, BRTS and PRTS signal, and thereafter transmitting both a request to send (RTS) signal and the PrRTS signal; receiving a clear to send (CTS) signal in response to the RTS and PrRTS signals, the CTS signal including a SNR for the PrRTS signal; computing a SNR correction factor based at least in part on the SNR for the PrRTS signal; and transmitting a data packet at a power level that is computed based at least in part on the SNR correction factor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for controlling the transmit power of a first wireless node communicating with a second wireless node over an asymmetric radio link in an ad-hoc wireless network, comprising:
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computing an initial transmit power for a probing request to send (PrRTS) packet that is transmitted from the first wireless node and that is transmitted in connection with a request to send (RTS) packet; receiving from the second node a clear to send (CTS) packet that includes at least a signal to noise ratio (SNR) for the PrRTS packet as received by the second wireless node; computing a SNR correction factor based at least in part on the SNR for the PrRTS signal; and transmitting a data packet at a power level that is computed based at least in part on the SNR correction factor. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26)
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27. A method for controlling transmit power, comprising:
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computing a signal to noise ration (SNR) for one of a received hello request to send (HRTS) packet, broadcast request to send (BRTS) packet and packet request to send (PRTS) packet; transmitting a request to send (RTS) packet and a probing request to send (PrRTS) packet, wherein a transmit power for the PrRTS packet is determined at least in part on the SNR of the HRTS, BRTS and PRTS packet; receiving a clear to send (CTS) packet in response to the RTS and PrRTS packets, the CTS packet including a SNR for the PrRTS signal; computing a SNR correction factor based at least in part on the SNR for the PrRTS signal; and transmitting a data packet at a power level that is determined based at least in part on the SNR correction factor. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36)
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Specification