Network entry and device discovery for cognitive radio networks

• US 8,817,710 B2
• Filed: 11/24/2008
• Issued: 08/26/2014
• Est. Priority Date: 11/27/2007
• Status: Expired due to Fees

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Wang, Jianfeng, Challapali, Kiran
• Primary Examiner(s): Yao, Kwang B
• Assistant Examiner(s): LOO, JUVENA W
• Application Number:
  US12/744,409
• Publication Number:
  US 20100246434A1
• Time in Patent Office: 2,101 Days
• Field of Search: 370310-464
• US Class Current: 370/329
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 72/044 based on the type of the allocated resource

Abstract

A device (400) scans and classifies each channel within a spectrum of channels (215-270) as being occupied or unoccupied (255), and, if occupied, whether it is occupied by a primary user (240), a secondary user (230), or an unknown user (260). As a secondary device (400), transmissions are avoided on channels occupied by primary users (490). The device selectively joins an existing network of secondary devices, or establishes a new network on an unoccupied channel (125), based on the quality of service (QoS) that the channel can provide and/or other factors. If the device is paired with a target device (115), the paired device advertises itself on a selected channel (345-360) for a period that is at least as long as the time required to scan all channels, to facilitate discovery in the event that the target device is also in a search mode. The advertising duration randomly alternates (345) among integer multiples of the scan duration.

Claims

1. A method comprising:

selecting a channel of a plurality of available channels;

monitoring the channel to determine whether the channel is being used and, when the channel is determined as being used, to classify the channel being used as being one of;

used by a primary user,

used by one or more secondary users,

used by an unknown class of users;

storing the determination of whether the channel is being used, and the classification of the channel when the channel is being used; and

repeating the selecting and monitoring until each of the plurality of available channels has been classified;

wherein when the channel is being used by one or more secondary users, storing an identification of each of the one or more secondary users of the channel;

and the method further comprising accessing the stored identification of each secondary user to locate a target user, and when the target user is located, joining a network on the channel associated with the identification of the target user.

2. The method of claim 1, wherein determining the channel as being used by one or more secondary users comprises detecting one or more beacon signals.

3. The method of claim 2, wherein determining the channel as being used by a primary user comprises detecting features that are characteristic of the primary user.

4. The method of claim 3, wherein determining the channel as being used by an unknown class of users comprises detecting energy above a threshold that does not correspond to one or more beacons and does not correspond to the features that are characteristic of the primary user.

5. The method of claim 1, comprising informing a user of the classifications of one or more of the plurality of available channels.

6. The method of claim 1, comprising when at least one channel is being used by one or more secondary users, joining a network on the at least one channel.

7. The method of claim 6, wherein joining the network is based on one of a user directive, association with at least one of the one or more secondary users, association with the network, a QoS characteristic of the network, and an amount of traffic on the network.

8. The method of claim 1, comprising when at least one channel is unused, transmitting an advertising beacon on the at least one channel.

9. The method of claim 1, comprising receiving another classification of a channel of the plurality of channels from one of the secondary users, and modifying the classification of the channel based on the other classification.

10. The method of claim 1, comprising transmitting the classification of one or more of the plurality of channels to one or more of the secondary users.

11. A method comprising:

scanning a plurality of channels for a beacon of a target device for a scan duration

and when the beacon of the target device is not detected;

randomly selecting an advertise duration from among a set of predefined durations;

transmitting an advertising beacon on a select channel during the advertise duration;

and when a response to the advertising beacon is not received from the target device;

repeating the scanning of one or more of the plurality of channels and transmitting of the advertising beacon at another select channel; and

otherwise;

establishing communication with the target device.

12. The method of claim 11, comprising terminating the repeating, and transmitting the advertising beacon on one of the plurality of available channels.

13. The method of claim 12, wherein terminating the repeating is based on at least one of a predefined time limit, a predefined number of repetitions, a role of the target device, and a user input.

14. The method of claim 11, wherein selecting the select channel comprises selecting the select channel from among channels of the plurality of channels that do not exhibit use by a primary user.

15. The method of claim 11, wherein the repeating comprises storing a record of each scanned channel being one of used by a primary user, used by one or more secondary users, used by an unknown class of users.

16. The method of claim 11, wherein values of the set of predefined durations are dependent upon the scan duration.

17. The method of claim 16, wherein values of the set of predefined durations comprise the scan duration and twice the scan duration.

18. The method of claim 11, wherein the one or more of the plurality of channels are selected from among channels at which a primary user was not detected during the scanning.

19. A method of network discovery by a device among a plurality of channels having primary and secondary users, comprising:

when the device is paired with a target device;

when the device is not a master of a master-slave pair;

scanning a plurality of channels for a beacon of the target device for a scan duration;

when the beacon of the target device is not detected;

transmitting an advertising beacon on a select channel during an advertise duration;

when a response to the advertising beacon is not received from the target device, repeating the scanning of one or more of the plurality of channels and transmitting of the advertising beacon at another select channel;

otherwise, when the device is the master of the master-slave pair, transmitting an advertising beacon on a select channel;

establishing communication with the target device;

otherwise, when the device is not paired with the target device;

selecting a channel of the plurality of available channels;

monitoring the channel to determine a classification of the channel based at least upon whether a primary or secondary user is detected;

storing the classification of the channel;

repeating the selecting and monitoring until each of the plurality of available channels has been classified;

selecting a select channel from among one or more of the plurality of channels at which at least one secondary user is detected, and

establishing communication with the at least one secondary user on the select channel.

20. An apparatus comprising:

a receiver;

a transmitter;

a controller that is configured to control the receiver to tune to each channel of a plurality of channels;

a channel classifier that is configured to determine a classification of each channel as being one of;

used by a primary user,

used by one or more secondary users,

used by an unknown class of users;

a memory that is configured to store the classification of each channel;

wherein when the channel is being used by one or more secondary users, the memory is further configured to store an identification of each of the one or more secondary users of the channel,

wherein the controller is configured to control the transmitter to selectively effect each of;

accessing the stored identification of each secondary user to locate a target user, and when the target user is located, joining a network on the channel associated with the identification of the target user; and

establishing a network on a select channel that is unused.

21. The apparatus of claim 20, wherein the controller is configured to selectively join the network based on one of a user directive, association with at least one of the one or more secondary users, association with the network, a QoS characteristic of the network, and an amount of traffic on the network.

22. An apparatus comprising:

a receiver;

a transmitter;

a controller that is configured to;

control the receiver to scan each of a plurality of channels for a beacon of a target device for a scan duration;

when the beacon of the target device is not detected;

randomly select an advertise duration from among a set of predefined durations;

control the transmitter to transmit an advertising beacon on a select channel during the advertise duration;

when a response to the advertising beacon is not received from the target device, repeating the control of the receiver to scan one or more of the plurality of channels and the control of the transmitter to transmit the advertising beacon at another select channel; and

otherwise, when the target device is detected, control the transmitter and receiver to establish communication with the target device.

23. The apparatus of claim 22, wherein the controller is configured to terminate the repeating of the scan of the one or more of the plurality of channels based on at least one of a predefined time limit, a predefined number of repetitions, a role of the target device, and a user input;

and transmitting the advertising beacon on one of the plurality of available channels.