Sensor-assisted aloha for wireless networks

• US 6,404,750 B1
• Filed: 08/13/1998
• Issued: 06/11/2002
• Est. Priority Date: 08/13/1998
• Status: Expired due to Fees

• Current Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Original Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Inventors: Wicker, Stephen B., Fine, Terrence L.
• Primary Examiner(s): Vincent, David
• Assistant Examiner(s): Phunkulh, Bob A.
• Application Number:
  US09/133,609
• Time in Patent Office: 1,398 Days
• Field of Search: 370/328, 370/329, 370/330, 370/336, 370/337, 370/442, 370/458, 370/462, 455/422, 455/456, 455/457, 706/15, 706/16, 706/17, 706/21, 706/25, 706/40, 706/41
• US Class Current: 370/329
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

The invention is made of an apparatus which incorporates a sensor-based means for stabilizing random access networks. In the preferred embodiment, a grid of sensors is used to gather energy measurements for analysis. In a preferred embodiment a neural network has been trained to estimate the number of colliding users in a given slot. This information is used to set parameters in a backoff algorithm so as to stabilize the network and minimize the delay experienced by users. The invention has the ability to locate users geographically within the network coverage area. This information can be used in conjunction with a steerable beam or an array of antennas to develop geographically-determined Aloha subchannels, further increasing the capacity of the system.

Claims

1. A system for stabilizing a random access protocol within a cell of a wireless communications network comprising:

a field of energy measuring sensors for providing data, said sensors distributed substantially within the cell;

means for receiving said data from the energy measuring sensors;

means for determining from said data a number of overlapping users seeking access to the wireless communications network; and

means for reducing the delay time before the users obtain access to the wireless communications network in response to the determination of the number of overlapping users.

2. The system as defined in claim 1 wherein said means for reducing the delay time comprises a random access protocol slotted Aloha.

3. The system as defined in claim 1 wherein said means for reducing the delay time comprises means for varying a retransmission delay time in proportion to the number of overlapping users seeking access.

4. The system as defined in claim 1 wherein said means for determining the number of overlapping users seeking access comprises means for neural net processing of said data.

5. A system for determining the location of active users seeking access within a cell of a wireless communications network comprising:

a grid of energy measuring sensors providing data, said sensors distributed within said cell,

means for detecting said data;

means for determining from said data the transmitted energy in a given bandwidth in a given region of said cell;

a neural net for processing said transmitted energy data, said neural net trained in propagation characteristics of said cell; and

means for determining the location of the active users seeking access to the wireless communications network from said processed transmitted energy data.

7. The system as defined in claim 5 further comprising a random access protocol means for reducing delay in gaining access by the active users seeking access to the wireless communications network.

8. The system as defined in claim 7 wherein said random access protocol means comprises slotted Aloha.

9. The system as defined in claim 8 further comprising means for locating geographically said groupings of active users seeking access by defining subchannels using distinct antenna beams.

6. A system for determining the location of active users seeking access within a cell of a wireless communications network comprising:

a grid of energy measuring sensors providing data, said sensors distributed within said cell;

means for detecting said data;

means for determining from said data the transmitted energy in a given bandwidth in a given region of said cell;

means for determining the location of the active users seeking access to the wireless communications network from said transmitted energy in a given bandwidth and said given region of said cell;

means for grouping said active users seeking access to a wireless communications network by location; and

means for using said groupings for reducing delay in gaining access to the wireless communications network by said active users seeking access.

10. A system for determining, in a random access protocol within a cell of a wireless communications network, whether a user who has gained access to the wireless communications network was a new or a backlogged user comprising:

a field of energy measuring sensors for providing data, said sensors distributed substantially within the cell;

means for receiving said data from the energy measuring sensors, and, from said data, determining a number of users seeking access to the wireless communications network at one or more points in time, and means for determining a footprint for the backlogged user;

means for determining a footprint of the user who gained access; and

means for determining if the user who gained access was the backlogged user, responsive to said means for determining a footprint of the user.

11. The system as defined in claim 10 wherein said means for determining if the user who gained access was a backlogged user comprises means for processing the footprint of the user who gained access from the footprint for the backlogged user wherein a negative value at any one of said sensors indicates that the user who gained access was not the backlogged user.

12. A method for stabilizing a random access protocol within a cell of a wireless communications network comprising the steps of:

providing data from a field of energy measuring sensors, said sensors distributed substantially within the cell;

receiving said data from the energy measuring sensors;

determining from said data a number of overlapping users seeking access to the wireless communications network; and

in response to the determination of the number of overlapping user;

reducing delay time before the overlapping users obtain access.

13. The method as defined in claim 12 wherein the step of reducing the delay time comprises using a slotted Aloha random access protocol.

14. The method as defined in claim 12 wherein the step of reducing the delay time before the overlapping users obtain access comprises the step of varying a retransmission delay time in proportion to the number of overlapping users seeking access.

15. The method as defined in claim 12 wherein the step of determining the number of overlapping users seeking access comprises neural net processing of said data.

16. A method for determining a location of active users within a cell of a wireless communications network using energy measuring sensor data from a grid of sensors distributed in the cell comprising the steps of:

providing a set of training data including signal propagation characteristics of the cell;

training a neural net with said training data;

detecting and measuring transmitted energy in a given bandwidth in a given region of said cell; and

responsive to said detected and measured transmitted energy, determining with said trained neural net the location of the active users.

17. A method for determining a location of active users within a cell of a wireless communications network using energy measuring sensor data from a grid of sensors distributed in the cell comprising the steps of:

detecting and measuring transmitted energy in a given bandwidth in a given region of said cell;

responsive to said detected and measured transmitted energy, determining the location of the active users;

grouping the active users seeking access to the wireless communications network by location; and

responsive to said groupings of the active users, reducing the delay in gaining access to the wireless communications network by said active users.

18. The method as defined in claim 17 further comprising the step of:

reducing delay in gaining access by said active users to the wireless communications network by using a random access protocol.

19. The method as defined in claim 18 wherein said random access protocol comprises implementing slotted Aloha.

20. The method as defined in claim 19 wherein implementing slotted Aloha comprises the step of locating geographically said groupings of the active users by defining subchannels using distinct antenna beams.

21. A method for determining, in a random access protocol within a cell of a wireless communications network, whether a user who has gained access to the communications network was a new or a backlogged user comprising the steps of:

providing data from a field of energy measuring sensors, said sensors distributed substantially within the cell;

receiving said data from the energy measuring sensors,

from said data, determining a number of users seeking access at one or more points in time,

determining a footprint for the backlogged user;

determining a footprint of the user who gained access; and

comparing the footprint for the backlogged user with the footprint of the user who gained access to determine if the user who gained access was the backlogged user.

22. The method as defined in claim 21 wherein said step of comparing comprises the step of processing the footprint of the user who gained access from the footprint for the backlogged user, wherein a negative value at any one of said sensors indicates that the user who gained access was not the backlogged user.