NEIGHBOR DISCOVERY OVER MULTIPLE CHANNELS FOR WIRELESS NETWORKS WITH DIRECTIONAL ANTENNAS

• US 20100142460A1
• Filed: 01/16/2008
• Published: 06/10/2010
• Est. Priority Date: 01/16/2007
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Chen, Richard, Chou, Chun-Ting, Zhai, Hong
• Granted Patent: US 8,498,250 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 84/20 Master-slave selection or change arrangements

Abstract

A communication system includes first and second devices, where a processor of at least one of the first device and the second device is configured to establish a superframe having a superframe duration (T_s) and transmit a beacon by the first device during each of the superframe duration (T_s); scan by the second device all sectors (N_beam) by scanning each sector for a superframe duration (T_s) and repeating a jump sequence. The jump sequence has a sequence duration (T_total) which is equal to a sum of a control duration (T_c) of a control channel and durations of data channels (KT_d). The processor is further configured to find the first device by the second device during a find time (T_f), where the control duration (T_c) is greater than the durations of data channels (KT_d).

Claims

1. A method for communication between a first device having a first directional antenna and a second device having a second directional antenna, the method comprising the acts of:

establishing a superframe having a superframe duration (T_s) and transmitting a beacon by the first device during each of the superframe duration (T_s);

powering on the second device;

scanning by the second device for two scan periods of all sectors (2N_beamT_s) in each scan period, the second device scanning all the sectors (N_beam) by scanning each sector for a superframe duration (T_s);

repeating a jump sequence, the jump sequence having a sequence duration (T_total) which is equal to a sum of a control duration (T_c) of a control channel and durations of data channels (KT_d);

establishing a new superframe if no existing beacons are detected on the control channel, or joining an existing superframe on the control channel during the control duration (T_c) if existing beacons are detected on the control channel;

scanning by the second device during a duration of a data channel (T_d);

finding the first device by the second device during a find time (T_f);

selecting a common channel to start communication with the first device over the common channel and stopping the jump sequence.

2. The method of claim 1, wherein the control duration (T_c) is greater than the durations of data channels (KT_d).

3. The method of claim 1 wherein, when the first device is repeating the jump sequence, the find time (T_f) is less than or equal to sequence duration (T_total) multiplied by time for scanning all the sectors (N_beamT_s) divided by the duration of the data channel (T_d).

4. The method of claim 1 wherein, when the first device is communicating with other devices after stopping the jump sequence, the find time (T_f) satisfies the following relationship:

$T_f\le <br><br>T_{\mathrm{total}}\times <br><br>\frac{T_s}{T_d}\times <br><br>N_{\mathrm{beam}}$

where T_total=T_c+KT_d,

K is a number of the data channels,

T_c is a duration of the control channel,

T_s is the superframe duration,

T_d is a duration of the data channel, and

N_beam is a total number of sectors scanned by the second device.

5. The method of claim 1 wherein, when the first device is communicating with other devices after stopping the jump sequence, the duration of the data channel (T_d) satisfies the following relationship:

$T_d\le <br><br>T_{\mathrm{total}}\times <br><br>\frac{T_s}{T_f}\times <br><br>N_{\mathrm{beam}}$

where T_total=T_c+KT_d,

K=number of the data channels,

T_c is a duration of the control channel,

T_f is a time needed for the second device to find the first device, and

N_beam is a total number of sectors scanned by the second device.

6. The method of claim 1 wherein, when the first device is repeating the jump sequence or when the jump sequence for the second device has a different start time than a start time of the jump sequence for the first device, the finding act finds the first device on the control channel by the second device.

7. The method of claim 1 wherein, when the first device is communicating with other devices after stopping the jump sequence, the finding act finds the first device on the control channel by the second device.

8. The method of claim 1 wherein, when the jump sequence for the second device has a different start time than a start time of the jump sequence for the first device, then the find time (T_f) satisfies the following relationship:

$T_f\le <br><br>T_{\mathrm{total}}\times <br><br>\frac{T_s}{T_c-{\mathrm{KT}}_d}\times <br><br>N_{\mathrm{beam}}$

where T_total=T_c+KT_d,

K is a number of the data channels,

T_c is a duration of the control channel,

T_s is the superframe duration,

T_d is a duration of the data channel, and

N_beam is a total number of sectors scanned by the second device.

9. A communication system comprising a first device and a second device, wherein a processor of at least one of the first device and the second device is configured to:

establish a superframe having a superframe duration (T_s) and transmit a beacon by the first device during each of the superframe duration (T_s);

scan by the second device for two scan periods of all sectors (2N_beamT_s) in each scan period, the second device scanning all sectors (N_beam) by scanning each sector for a superframe duration (T_s);

repeat a jump sequence, the jump sequence having a sequence duration (T_total) which is equal to a sum of a control duration (T_c) of a control channel and durations of data channels (KT_d);

establish a new superframe if no existing beacons are detected on the control channel, or joining an existing superframe on the control channel during the control duration (T_c) if existing beacons are detected on the control channel;

scan by the second device during a duration of a data channel (T_d);

find the first device by the second device during a find time (T_f); and

select a common channel to start communication with the first device over the common channel and stopping the jump sequence.

10. The communication system of claim 9, wherein the control duration (T_c) is greater than the durations of data channels (KT_d).

11. The communication system of claim 9, wherein, when the first device is repeating the jump sequence, the find time (T_f) is less than or equal to sequence duration (T_total) multiplied by time for scanning all the sectors (N_beamT_s) divided by a duration of a data channel (T_d).

12. The communication system of claim 9, wherein, when the first device is communicating with other devices after stopping the jump sequence, the find time (T_f) satisfies the following relationship:

$T_f\le <br><br>T_{\mathrm{total}}\times <br><br>\frac{T_s}{T_d}\times <br><br>N_{\mathrm{beam}}$

where T_total=T_c+KT_d,

K is a number of the data channels,

T_c is a duration of the control channel,

T_s is the superframe duration,

T_d is a duration of the data channel, and

N_beam is a total number of sectors scanned by the second device.

13. The communication system of claim 9, wherein, when the first device is communicating with other devices after stopping the jump sequence, the duration of a data channel (T_d) satisfies the following relationship:

$T_d\le <br><br>T_{\mathrm{total}}\times <br><br>\frac{T_s}{T_f}\times <br><br>N_{\mathrm{beam}}$

where T_total=T_c+KT_d,

K=number of the data channels,

T_c is a duration of the control channel,

T_f is a time needed for the second device to find the first device, and

N_beam is a total number of sectors scanned by the second device.

14. The communication system of claim 9 wherein, when the first device is repeating the jump sequence or when the jump sequence for the second device has a different start time than a start time of the jump sequence for the first device, the processor is configured to find the first device on the control channel by the second device.

15. The communication system of claim 9 wherein, when the first device is communicating with other devices after stopping the jump sequence, the processor is configured to find the first device on the control channel by the second device.

16. The communication system of claim 9 wherein, when the jump sequence for the second device has a different start time than a start time of the jump sequence for the first device, then the find time (T_f) satisfies the following relationship:

$T_f\le <br><br>T_{\mathrm{total}}\times <br><br>\frac{T_s}{T_c-{\mathrm{KT}}_d}\times <br><br>N_{\mathrm{beam}}$

where T_total=T_c+KT_d,

K is a number of the data channels,

T_c is a duration of the control channel,

T_s is the superframe duration,

T_d is a duration of the data channel, and

N_beam is a total number of sectors scanned by the second device.

17. A computer program product stored on a computer readable medium, the computer program when executed by a processor is configured to:

establish a superframe having a superframe duration (T_s) and transmit a beacon by the first device during each of the superframe duration (T_s);

scan by the second device for two scan periods of all sectors (2N_beamT_s) in each scan period, the second device scanning all sectors (N_beam) by scanning each sector for a superframe duration (T_s);

repeat a jump sequence, the jump sequence having a sequence duration (T_total) which is equal to a sum of a control duration (T_c) of a control channel and durations of data channels (KT_d);

establish a new superframe if no existing beacons are detected on the control channel, or joining an existing superframe on the control channel during the control duration (T_c) if existing beacons are detected on the control channel;

scan by the second device during a duration of a data channel (T_d);

find the first device by the second device during a find time (T_f) which is less than or equal two scan periods of all the sectors (2N_beamT_s); and

selecting a common channel to start communication with the first device over the common channel and stopping the jump sequence.

18. The computer program product of claim 17, wherein the control duration (T_c) is greater than the durations of data channels (KT_d).

19. The computer program product of claim 17 wherein, when the first device is repeating the jump sequence, the find time (T_f) is less than or equal to sequence duration (T_total) multiplied by time for scanning all the sectors (N_beamT_s) divided by a duration of a data channel (T_d).

20. The computer program product of claim 17 wherein, when the first device is communicating with other devices after stopping the jump sequence, the find time (T_f) satisfies the following relationship:

$T_f\le <br><br>T_{\mathrm{total}}\times <br><br>\frac{T_s}{T_d}\times <br><br>N_{\mathrm{beam}}$

where T_total=T_c+KT_d,

K is a number of the data channels,

T_c is a duration of the control channel,

T_s is the superframe duration,

T_d is a duration of the data channel, and

N_beam is a total number of sectors scanned by the second device.

21. The computer program product of claim 17 wherein, when the first device is communicating with other devices after stopping the jump sequence, the duration of a data channel (T_d) satisfies the following relationship:

$T_d\le <br><br>T_{\mathrm{total}}\times <br><br>\frac{T_s}{T_f}\times <br><br>N_{\mathrm{beam}}$

where T_total=T_c+KT_d,

K=number of the data channels,

T_c is a duration of the control channel,

T_f is a time needed for the second device to find the first device, and

N_beam is a total number of sectors scanned by the second device.

22. The computer program product of claim 17 wherein, when the first device is repeating the jump sequence or when the jump sequence for the second device has a different start time than a start time of the jump sequence for the first device, the processor is configured to find the first device on the control channel by the second device.

23. The computer program product of claim 17 wherein, when the first device is communicating with other devices after stopping the jump sequence, the processor is configured to find the first device on the control channel by the second device.

24. The computer program product of claim 17 wherein, when the jump sequence for the second device has a different start time than a start time of the jump sequence for the first device, then the find time (T_f) satisfies the following relationship:

$T_f\le <br><br>T_{\mathrm{total}}\times <br><br>\frac{T_s}{T_c-{\mathrm{KT}}_d}\times <br><br>N_{\mathrm{beam}}$

where T_total=T_c+KT_d,

K is a number of the data channels,

T_c is a duration of the control channel,

T_s is the superframe duration,

T_d is a duration of the data channel, and

N_beam is a total number of sectors scanned by the second device.