Hybrid coordination function (HCF) access through tiered contention and overlapped wireless cell mitigation
First Claim
1. A method for reducing interference between overlapping first and second wireless cells in a medium, each wireless cell including a respective plurality of member stations and an overlapped station occupying both wireless cells, comprising:
- assigning an inter-cell contention-free period having a value to a first member station in the first wireless cell, associated with an accessing order in the medium for member stations in the first and second wireless cells;
transmitting by the first member station in the first wireless cell, a beacon packet containing the value;
receiving the beacon packet at the overlapped station and forwarding the value to the member stations in the second wireless cell; and
delaying transmissions by the member stations in the second wireless cell until after the inter-cell contention-free period.
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Accused Products
Abstract
A method and system reduce interference between overlapping first and second wireless LAN cells in a medium. Each cell includes a respective plurality of member stations and there is at least one overlapped station occupying both cells. An inter-cell contention-free period value is assigned to a first access point station in the first cell, associated with an accessing order in the medium for member stations in the first and second cells. The access point transmits a beacon packet containing the inter-cell contention-free period value, which is intercepted at the overlapped station. The overlapped station forwards the inter-cell contention-free period value to member stations in the second cell. A second access point in the second cell can then delay transmissions by member stations in the second cell until after the inter-cell contention-free period expires. The beacon packet sent by the first access point station also includes an inter-cell contention-free period value, which causes the member stations in the first cell to delay accessing the medium until polled by the first access point. After the expiration of the intra-cell contention-free period, member stations in the first cell may contend for the medium based on the quality of service (QoS) data they are to transmit, using the Tiered Contention Multiple Access (TCMA) protocol.
102 Citations
40 Claims
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1. A method for reducing interference between overlapping first and second wireless cells in a medium, each wireless cell including a respective plurality of member stations and an overlapped station occupying both wireless cells, comprising:
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assigning an inter-cell contention-free period having a value to a first member station in the first wireless cell, associated with an accessing order in the medium for member stations in the first and second wireless cells; transmitting by the first member station in the first wireless cell, a beacon packet containing the value; receiving the beacon packet at the overlapped station and forwarding the value to the member stations in the second wireless cell; and delaying transmissions by the member stations in the second wireless cell until after the inter-cell contention-free period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A wireless communications system having reduced interference between overlapping first and second wireless cells in a medium, each wireless cell including a respective plurality of member stations and an overlapped station occupying both wireless cells, comprising:
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a first access point station in the first wireless cell having an inter-cell contention-free period having a value associated with an accessing order in the medium for the member stations in the first and second wireless cells; the first access point station transmitting a beacon packet containing the value; an overlapped station occupying both wireless cells receiving the beacon packet and forwarding the value to the member stations in the second wireless cell; and a second access point station in the second wireless cell receiving the value and delaying transmissions by the member stations in the second wireless cell until after the inter-cell contention-free period. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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37. A method for reducing interference between overlapping wireless cells, each wireless cell including an access point and a plurality of member stations, comprising:
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assigning to a first access point in a first wireless cell, a first contention-free period having a first value; assigning to first member stations in the first wireless cell, a first backoff value for first high quality of service data and a second backoff value for first low quality of service data; assigning to a second access point in a second wireless cell that overlaps the first wireless cell, a second contention-free period having a second value that is longer than the first value; assigning to second member stations in the second wireless cell, a third backoff value for second high quality of service data and a fourth backoff value for second low quality of service data; transmitting a first beacon packet including the first value, from the first access point to the first member stations in the first wireless cell; transmitting a second beacon packet including the second value, from the second access point to the second member stations in the second wireless cell; transmitting a first contention-free time response frame containing the first value, from the first member stations, for alerting the second access point and the second member stations in the second wireless cell, that the medium has been seized by the first access point; waiting for the first contention-free period at the first member stations to begin counting down the first backoff for the first high quality of service data and then transmitting the first high quality of service data; waiting for the second contention-free period at the second member stations to begin counting down the third backoff for the second high quality of service data and then transmitting the second high quality of service data; waiting for the first contention-free period at the first member stations to begin counting down the second backoff for the first low quality of service data and then transmitting the first low quality of service data; and waiting for the second contention-free period at the second member stations to begin counting down the fourth backoff for the second low quality of service data and then transmitting the second low quality of service data. - View Dependent Claims (38, 39, 40)
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Specification