Preemptive roaming in a cellular local area wireless network
First Claim
1. A data communications network including a plurality of stationary access points operatively connected to a host and a plurality of mobile units, said network comprising:
- a) each of the mobile units using frequency hopping spread spectrum radio frequency communications, and including a transmitter for broadcasting a probe packet to all of the access points in a predetermined range from one of the mobile units that is broadcasting the probe packet,b) said access points within said range including respective receivers for detecting the probe packet being broadcast, and for responsively sending probe response packets back to said one of the mobile units, andc) a selector in each of the mobile units to select a most eligible one of the access points from said probe response packets, and to associate said one of the mobile units with the most eligible one of the access points at predetermined intervals, the most eligible one of the access points being selected according to received signal quality at said one of the mobile units, and a loading factor at each of the stationary access points.
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Accused Products
Abstract
A communications network comprising a cellular local area wireless network includes a plurality of access points connected to a housed computer and each other, and a plurality of mobile units each mobile unit being arranged for association with an access point. The mobile units are arranged to periodically scan for and identify the most eligible access point for association on the basis of the criteria of best quality signal strength and loading factor. In order to identify when mobile units are being removed from a predetermined area, access points having directional antennae are situated adjacent exit points to detect when mobile units are in a vicinity.
377 Citations
31 Claims
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1. A data communications network including a plurality of stationary access points operatively connected to a host and a plurality of mobile units, said network comprising:
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a) each of the mobile units using frequency hopping spread spectrum radio frequency communications, and including a transmitter for broadcasting a probe packet to all of the access points in a predetermined range from one of the mobile units that is broadcasting the probe packet, b) said access points within said range including respective receivers for detecting the probe packet being broadcast, and for responsively sending probe response packets back to said one of the mobile units, and c) a selector in each of the mobile units to select a most eligible one of the access points from said probe response packets, and to associate said one of the mobile units with the most eligible one of the access points at predetermined intervals, the most eligible one of the access points being selected according to received signal quality at said one of the mobile units, and a loading factor at each of the stationary access points. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A method of operating a cellular communications network including a plurality of access points in communication with each other and operatively connected to a host, and a plurality of mobile units, comprising the steps of:
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a) broadcasting a probe packet to all of the access points in a predetermined range from one of the mobile units that is broadcasting the probe packet, each of the mobile units using frequency hopping spread spectrum radio frequency communications; b) detecting the probe packet being broadcast, and responsively sending probe response packets from the access points within said range back to said one of the mobile units; c) minimizing interference among the probe response packets; d) scanning the plurality of the access points at predetermined intervals; and e) selecting a group of eligible ones of the access points from the plurality of the access points, by selecting a most eligible one of the access points from the group according to received signal quality at said one of the mobile units and loading factor.
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30. A data communications network, comprising:
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a) a plurality of stationary access points operatively connected to a host, a plurality of mobile units, each of the mobile using frequency hopping spread spectrum radio frequency communications, one of the mobile units including a transmitter for broadcasting a probe packet to all of the access points in a predetermined range from said one of the mobile units that is broadcasting the probe packet, b) said access points within said range including respective receivers for detecting the probe packet being broadcast, and for responsively sending probe response packets back to said one of the mobile units, c) a selector for selecting a most eligible one of the access points from the plurality of the access points on the basis of received signal quality at said one of the mobile units and loading factor at each of the access points, and d) a physical area within which all the mobile units are kept, said area having an exit adjacent which one of the access points is located. - View Dependent Claims (31)
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Specification