Hybrid coordination function (HCF) access through tired contention and overlapped wireless cell mitigation
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.
1. A method comprising:
using a value for a first inter-cell contention-free period by a first access point station in a first cell in a beacon packet, the value associated with an accessing order in a medium for member stations in a second cell of a plurality of cells during a transmission frame, where the value of the first inter-cell contention-free period is to be used as a notice that the first cell has seized the medium for a period of time represented by the value; and
transmitting by the first access point station in the first cell, the beacon packet containing the value for the first inter-cell contention-free period, wherein the beacon packet is for an overlapped station that is occupying the first cell and the second cell, and the beacon packet is for enabling the value for the first inter-cell contention-free period to be forwarded to the member stations in the second cell, for delaying transmissions by the member stations in the second cell until after the first inter-cell contention free period has expired.
2. The method of claim 1 , further comprising:
assigning a value for a second inter-cell contention-free period to a second access point station in the second cell, associated with the accessing order;
transmitting by the second access point station in the second cell, a second beacon packet containing the value of the second inter-cell contention-free period; and
receiving the second beacon packet at the overlapped station occupying the first cell and the second cell, and forwarding the value of the second inter-cell contention-free period to member stations in the first cell to delay transmissions by the member stations in the first cell until after the second inter-cell contention-free period has expired.
3. The method of claim 2 , further comprising:
receiving the value of the first inter-cell contention-free period and the value of the second inter-cell contention-free period at a third access point station in a third cell;
selecting a backoff time for the third access point station following the second inter-cell contention-free period, to begin transmission by the third access point station in the third cell of a third beacon packet containing a value for a third inter-cell contention-free period; and
receiving the third beacon packet at the overlapped station occupying the first cell and occupying the second cell, and forwarding the third value of the third inter-cell contention-free period to the member stations in the first cell and the second cell to delay transmissions by the member stations in the first cell and the second cell until after the third inter-cell contention-free period has expired.
4. The method of claim 2 , further comprising:
transmitting in the first beacon packet to the member stations in the first cell, a value for an intra-cell contention-free period, during which the member stations in the first cell will delay accessing the medium.
5. The method of claim 2 , further comprising:
transmitting a peg packet by the second access point station in the second cell to deter the member stations in the first cell from contending for the medium.
6. A method comprising:
using a value for a first inter-cell contention-free period by a first access point station in a first cell in a beacon packet, the value associated with an accessing order in the medium for member stations in a second cell of a plurality of cells during a transmission frame, where the value of the first inter-cell contention-free period is to be used as a notice that the first cell has seized the medium for a period of time represented by the value; and
transmitting by the first access point station in the first cell, a beacon packet containing the value of the first inter-cell contention-free period.
7. The method of claim 6 , wherein the beacon packet is transmitted to an overlapped station that is occupying the first cell and the second cell.
8. The method of claim 6 , wherein the beacon packet is for enabling the value for the first inter-cell contention-free period to be forwarded to the member stations in the second cell, for delaying transmissions by the member stations in the second cell until after the first inter-cell contention free period has expired.
9. The method of claim 6 , further comprising:
receiving the value of the first inter-cell contention-free period and a value of a second inter-cell contention-free period from a second access point station in the second cell, at a third access point station in a third cell; and
selecting a backoff time for the third access point station following the second inter-cell contention free period, to begin transmission by the third access point station in the third cell of a third beacon packet containing a value for a third inter-cell contention-free period.
10. The method of claim 9 , further comprising:
receiving the value of the third inter-cell contention-free period at member stations in the first cell and the second cell to delay transmissions by the member stations in the first cell and the second cell until after the third inter-cell contention-free period has expired.
11. The method of claim 9 , further comprising:
transmitting a peg packet by the third access point station in the third cell to deter member stations in the first cell from contending for the medium.
12. The method of claim 6 , further comprising:
transmitting in the first beacon packet to member stations in the first cell, a value for an intra-cell contention-free period, during which the member stations in the first cell will delay accessing the medium.
13. A system comprising:
a first access point station for using a value for a first inter-cell contention-free period in a beacon packet, the first access point station is in a first cell, the value associated with an accessing order in a medium for member stations in a second cell of a plurality of cells during a transmission frame, where the value of the first inter-cell contention-free period is to be used as a notice that the first cell has seized the medium for a period of time represented by the value, the first access point station in the first cell for transmitting the beacon packet containing the value of the first inter-cell contention-free period, wherein the beacon packet is for an overlapped station that is occupying the first cell and the second cell, and for enabling the value for the first inter-cell contention-free period to be forwarded to member stations in the second cell, to delay transmissions by member stations in the second cell until after the first inter-cell contention free period has expired; and
the overlapped station.
14. The system of claim 13 , further comprising:
a second access point station using a value for a second inter-cell contention-free period, the second access point station in the second cell, the value for the second inter-cell contention-free period associated with the accessing order;
the second access point station in the second cell for transmitting a second beacon packet containing the value of the second inter-cell contention-free period; and
the overlapped station occupying the first cell and the second cell for receiving the second beacon packet and forwarding the value of the second inter-cell contention-free period to member stations in the first cell to delay transmissions by the member stations in the first cell until after the second inter-cell contention-free period has expired.
15. The system of claim 14 , further comprising:
a third access point station in a third cell for receiving the value of the first inter-cell contention-free period and the value of the second inter-cell contention-free period;
the third access point station using a backoff time following the second inter-cell contention-free period, to begin transmission by the third access point station in the third cell of a third beacon packet containing a value for a third inter-cell contention-free period; and
the overlapped station occupying the first cell and occupying the second cell for receiving the third beacon packet and forwarding the value of the third inter-cell contention-free period to the member stations in the first cell and the second cell to delay transmissions by the member stations in the first cell and the second cell until after the third inter-cell contention-free period has expired.
16. The system of claim 13 , the first access point station for transmitting in the first beacon packet to member stations in the first cell, a value for an intra-cell contention-free period, during which the member stations in the first cell will delay accessing the medium.
17. The system of claim 13 , further comprising:
the second access point station in the second cell for transmitting a peg packet to deter member stations in the first cell from contending for the medium.