Channel selection
First Claim
1. A wireless communications relay device, comprising:
- a receiver for detecting transmissions from other such devices;
a transmitter for transmitting signals at a first power level for normal traffic, and a higher, inhibition level, in order that its transmissions may be detected by other such devices over a wider area than its normal operating range; and
a control means for selecting a channel and a transmission power on which the transmitter will operate, the control means being arranged to inhibit the transmitter from selecting channels detected by the receiver when the transmitter is operating at the inhibition level to prevent co-channel interference between transmitters of wireless communications relay devices that are not in the normal operating range of each other but whose normal operating ranges overlap.
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Accused Products
Abstract
Wireless devices in (10, 20, 30 etc) in an ad hoc network each select a channel on which to operate such that conflicts with neighbouring devices are avoided. Each device (20) has a normal power output, giving it a normal range (31) and an enhanced power output, giving it an extended “inhibition” range (33). Initially each device (20) transmits at the enhanced power level, such that it can be detected by devices (40, 50) within the extended range (33). If it detects other devices transmitting on the same channel, it may change to another channel. Once a channel has been identified on which no conflict is detected, the device (20) switches to the normal power level. By initiating the channel selection process at the enhanced level, conflicts between the transmissions of devices (20, 40), which would be detectable at a device (30) within the normal range of both, can be avoided despite the two devices (20, 40) not be able to detect each other directly at the normal power level. To conserve battery power, the process is arranged to have the devices operate at the enhanced power for the minimum time necessary, by dropping to the normal level when a suitable channel has been identified with a reasonable degree of certainty.
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Citations
18 Claims
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1. A wireless communications relay device, comprising:
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a receiver for detecting transmissions from other such devices; a transmitter for transmitting signals at a first power level for normal traffic, and a higher, inhibition level, in order that its transmissions may be detected by other such devices over a wider area than its normal operating range; and a control means for selecting a channel and a transmission power on which the transmitter will operate, the control means being arranged to inhibit the transmitter from selecting channels detected by the receiver when the transmitter is operating at the inhibition level to prevent co-channel interference between transmitters of wireless communications relay devices that are not in the normal operating range of each other but whose normal operating ranges overlap. - View Dependent Claims (2, 3, 4, 5, 6)
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- 7. A method of channel selection in a network of wireless communications relay devices, wherein each device is inhibited from operating on a channel detectable on transmissions received from another such device, when operating at an inhibition transmission power, in order to inhibit other such devices from selecting the same channel, wherein the inhibition transmission power is higher than the normal transmission power of the devices such that selection of the same channel is inhibited over a wider area than the normal operating range of the device to prevent co-channel interference between transmitters of wireless communications relay devices that are not in the normal operating range of each other but whose normal operating ranges overlap.
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15. A wireless communications relay device, comprising:
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a receiver that detects transmissions; a transmitter that transmits signals at a lower power level for establishing a narrower operating range and a higher power level for establishing a wider operating range so that a transmitted signal at the higher power level may be detected by another such device which is within the wider operating range but outside of the narrower operating range; and a controller that selects a channel and a transmission power on which the transmitter will operate, the controller being arranged to reduce a possibility of the transmitter selecting channels detected by the receiver when the transmitter is operating at the higher power level to reduce a possibility of co-channel interference between transmitters of wireless communications relay devices that are not in the narrower operating ranges of each other but whose narrower operating ranges overlap. - View Dependent Claims (16)
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17. A method of channel selection in a network of wireless communications relay devices, the method comprising:
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detecting, in at least one device, transmissions; transmitting, from the at least one device, signals at a lower transmission power for establishing a narrower operating range of the at least one device and a higher transmission power for establishing a wider operating range of the at least one device so that the transmitted signal at the higher transmission power may be detected by another such device which is within the wider operating range of the at least one device but outside of the narrower operating range of the at least one device; and selecting, when the at least one device is operating at the higher transmission power, a channel and a transmission power on which signals from the at least one device will be transmitted, such that a likelihood of a selection of the same channel as that of the another such device which is within the wider operating range of the at least one device but outside of the narrower operating range of the at least one device is reduced to reduce a likelihood of co-channel interference between transmissions of the at least one device and the another such device, the at least one device and the another such device not being within the narrower operating ranges of each other but whose narrower operating ranges overlap. - View Dependent Claims (18)
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Specification