Enhanced algorithm for initial AP selection and roaming
First Claim
1. A method for selecting an access point (AP) in a wireless network, comprising:
- (a) measuring a received signal strength indicator (RSSI) and obtaining a channel loading indicator for each AP in each frequency channel;
(b) setting a first and a second threshold for the RSSI and a third threshold for the channel loading indicator, wherein the second threshold is less than the first threshold;
(c) selecting the AP with the lowest channel loading indicator if an AP exists with an RSSI greater than or equal to the first threshold and a channel loading indicator less than the third threshold;
(d) if no AP is selected in (c), selecting the AP with the highest RSSI if an AP exists with an RSSI greater than or equal to the second threshold and a channel loading indicator less than the third threshold; and
(e) if no AP is selected in (d), selecting the AP with the lowest channel loading indicator if an AP exists with an RSSI greater than the second threshold.
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Abstract
In a wireless network, such as an 802.11 conformant wireless LAN, a wireless station selects an access point, e.g., during power-up or roaming, based on the received signal strength indicator (RSSI) and channel loading information. The RSSI information is measured by the receiving station when the beacon or probe response frame is received, and the channel loading information is communicated to the station through the beacon or probe response frames. The channel loading information is a percentage of time the access point is busy transmitting or receiving data during a reporting interval. By using both RSSI and channel loading information, performance is increased when the access point with the strongest signal is also the busiest. In this case, this access point would not be selected for association with the wireless station.
294 Citations
20 Claims
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1. A method for selecting an access point (AP) in a wireless network, comprising:
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(a) measuring a received signal strength indicator (RSSI) and obtaining a channel loading indicator for each AP in each frequency channel;
(b) setting a first and a second threshold for the RSSI and a third threshold for the channel loading indicator, wherein the second threshold is less than the first threshold;
(c) selecting the AP with the lowest channel loading indicator if an AP exists with an RSSI greater than or equal to the first threshold and a channel loading indicator less than the third threshold;
(d) if no AP is selected in (c), selecting the AP with the highest RSSI if an AP exists with an RSSI greater than or equal to the second threshold and a channel loading indicator less than the third threshold; and
(e) if no AP is selected in (d), selecting the AP with the lowest channel loading indicator if an AP exists with an RSSI greater than the second threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of selecting, from a plurality of access points in a wireless network, an access point by a wireless station, comprising:
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transmitting, by the access points, measuring signal strength information and obtaining channel loading information for each access point;
measuring, by the wireless station, the signal strength information for each access point;
receiving channel loading information for each access point; and
selecting an access point based on the signal strength and channel loading information. - View Dependent Claims (13, 14, 15)
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16. A wireless network, comprising:
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a plurality of access points, each access point comprising a transmitter for sending channel loading information; and
a plurality of wireless stations within communication range of the access points, wherein each wireless station comprises;
a receiver for measuring the signal strength and receiving channel loading information from the access points; and
a processor for selecting an access point based on the signal strength and channel loading information. - View Dependent Claims (17, 18, 19, 20)
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Specification