Frequency reuse in millimeter-wave point-to-multipoint radio systems

• US 6,421,542 B1
• Filed: 08/25/1999
• Issued: 07/16/2002
• Est. Priority Date: 05/13/1998
• Status: Active Grant

• Current Assignee: RPX Clearinghouse LLC (RPX Corporation)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Astell, Paul, Dean, Stuart, Sandler, Howard M.
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): Ferguson, Keith
• Application Number:
  US09/382,500
• Time in Patent Office: 1,056 Days
• Field of Search: 455/447, 455/561, 455/562, 455/450, 455/452, 455/453, 455/422, 455/424, 455/425, 455/509, 455/25, 455/500, 455/517, 455/550, 455/426, 455/403
• US Class Current: 455/561
• CPC Class Codes: H04W 16/12 Fixed resource partitioning
• CPC Class Codes: H04W 16/24 Cell structures

Abstract

A millimeter-wave point-to-multipoint LMDS radio system for broadband wireless access having frequency reuse that includes a cell area divided into an integer number k sub-sectors of equal angular arc 360/k degrees each; a hub having antennas each configured to generate an antenna beam that covers an integer number j sub-sectors, an angular gap i being defined between edges of coverage of one of the antennas where i is an integer number of sub-sectors; a total integer number of n channel sets each of at least one radio channel and each configured independent and free of interference from other ones of the channels in other ones of the channel sets, each of the channel sets having a number of uses defined by a quantity k/(i+j) that is an integer equal or greater than two, each channel set being deployed with a common re-use pattern with an angular stagger between antennas of (i+j)/n sub-sectors.

Claims

1. A millimeter-wave point-to-multipoint radio system having frequency reuse, comprising:

a cell area divided into an integer number k sub-sectors of equal angular arc 360/k degrees each;

a hub having antennas each configured to generate an antenna beam that covers an integer number j sub-sectors;

an angular gap i being defined between edges of coverage of any pair of the antennas where i is an integer number of sub-sectors;

a total integer number of n channel sets each of at least one radio channel and each configured independent and free of interference from other ones of the channels in other ones of the channel sets, each of the channel sets having a number of uses defined by a quantity k/(i+j) that is an integer equal or greater than two, each channel set being deployed with a common re-use pattern with an angular stagger between antennas of (i+j)/n sub-sectors.

2. A system as in claim 1, wherein the channel sets are arranged to cover each part of the cell by a uniform number of channel sets so that n=i+j, an angular stagger between k antennas being one sub-sector, with the k being also an integer that is indicative of a total number of antennas present at the hub.

3. A system as in claim 1, wherein neighboring ones of the antennas are arranged so that their antenna beams overlap between sub-sectors with j having a value that is greater than or equal to 2.

4. A system as in claim 3, wherein the remote stations are configured to dynamically re-tune from channels in one of the channel sets to channels in another of the channel sets in response to indication from the hub of current traffic conditions, the hub being configured to load balance as each of a plurality of remote stations comes within a coverage area of two channel sets by dynamically assigning the remote stations to one channel set or the other, depending on traffic conditions of the moment, to optimize use of both of the channel sets.

5. A system as in claim 3, wherein the hub is configured to broadcast information about current traffic loading in the channel sets, each of the remote stations being configured to autonomously choose which of the channel sets to use based on the information.

6. A system as in claim 3, further comprising memory in one remote station that is loaded with the one radio channel as a primary channel in the one channel set and is loaded with a secondary channel in another channel set, the one remote station being configured to tune to the primary channel and to monitor downstream signaling from the hub via one of the antennas, the remote station being configured to continuously check if communications with the hub on the primary channel needs to change and if so to tune to the secondary channel to re-establish communications with the hub.

7. A system as in claim 6, wherein the hub is configured to send a notification to the one remote station in response to the primary channel from the antenna becoming available again, the one remote station being configured to respond to the notification to retune to the primary channel again and re-establish communications with the hub via the one antenna.

8. A system as in claim 1, wherein the hub is configured to use kn/(i+j) antenna beams from the total number of antennas present at the hub.

9. A system as in claim 1, wherein a number of channels within each channel set being other than equal to each other.

10. A system as in claim 1, wherein the total number of sets available, n, is greater than 1+i/j so as to provide complete coverage of 360 degrees with no gaps of coverage.

11. A system as in claim 1, wherein a first of the antennas is arranged to provide coverage of a first of the j sub-sectors using a first channel set.

12. A system as in claim 1, wherein a next j-sectors are arranged after a gap of a next of the i sub-sectors and covered by another of the antennas and arranged to re-use the first channel set.

13. A system as in claim 1, wherein a number of times the first channel set is reused in the cell is equal to k/(i+j)>

=2.

14. A system as in claim 1, wherein subsequent n-1 channel sets set2, set3 . . . setn are spaced apart by i+j sub sectors and staggered in an angular manner.

15. A system as in claim 1, wherein variables k, j, i and n have values selected from a group consisting of a first set of values with k=6, j=2, i=1, n=3, a second set of values with k even, j=1, i=1, n=2 and a third set of values with k=6, j>

i, n=2.

16. A system as in claim 1, wherein the hub and antennas are configured to provide a traffic capacity proportional to a number of the channel sets in use, a normalized measure of the capacity being a number of beams per the hub divided by a number of the channel sets available, the normalized capacity being at least two.

17. A system as in claim 1, further comprising memory in one of the remote stations that is loaded with a primary one of the channels in the one channel set and is loaded with a secondary one of the channels in another channel set, the one remote station being configured to tune to the primary channel-and to monitor downstream signaling from the hub via one of the antennas, the remote station being configured to continuously check if communications with the hub on the primary channel needs to change and if so to tune to the secondary channel to re-establish communications with the hub.

18. A system as in claim 17, wherein the hub is configured to send a notification to the one remote station in response to the primary channel from the antenna becoming available again, the one remote station being configured to respond to the notification to retune to the primary channel again and re-establish communications with the hub via the one antenna.

19. A method of balancing traffic from users, comprising:

providing antennas within an existing hub to provide coverage, each of the antennas covering two sub-sectors of an area,

accepting traffic from remote stations within the area covered by the antennas,

providing communications through the antennas by using at least one radio channel of a channel set, the channel set being a set of at least one radio channel that is independent and free from interference from all other channels in the other channel sets,

balancing the traffic from certain users in one of the sub-sectors that is greater than the traffic from other users in an adjacent one of the sub-sectors, both the one sub-sector and the adjacent one of the sub-sectors being covered by a same one of the antennas, the remote stations dynamically re-tuning from channels in one of the channel sets to channels in another of the channel sets in response to indication from the hub of current traffic conditions, and

load balancing with the hub as each of the remote stations comes within a coverage area of two channel sets by dynamically assigning the remote stations to one channel set or the other, depending on traffic conditions of the moment, to optimize use of both of the channel sets.

20. A method of balancing traffic from users, comprising:

providing antennas within an existing hub to provide coverage, each of the antennas covering two sub-sectors of an area,

accepting traffic from remote stations within the area covered by the antennas,

providing communications through the antennas by using at least one radio channel of a channel set, the channel set being a set of at least one radio channel that is independent and free from interference from all other channels in the other channel sets,

balancing the traffic from certain users in one of the sub-sectors that is greater than the traffic from other users in an adjacent one of the sub-sectors, both the one sub-sector and the adjacent one of the sub-sectors being covered by a same one of the antennas, and

broadcasting with the hub information about current traffic loading in the channel sets, each of the remote stations autonomously choosing which of the channel sets to use based on the information.

21. A method of balancing traffic from users, comprising:

providing antennas within an existing hub to provide coverage, each of the antennas covering two sub-sectors of an area,

accepting traffic from remote stations within the area covered by the antennas,

providing communications through the antennas by using at least one radio channel of a channel set, the channel set being a set of at least one radio channel that is independent and free from interference from all other channels in the other channel sets,

balancing the traffic from certain users in one of the sub-sectors that is greater than the traffic from other users in an adjacent one of the sub-sectors, both the one sub-sector and the adjacent one of the sub-sectors being covered by a same one of the antennas, and

adding traffic capacity in the existing hub by providing overlapping beams to existing beams from the antennas without re-orienting existing ones of the antennas and without replacing existing ones of the antennas.

22. A method of balancing traffic from users, comprising:

providing antennas within an existing hub to provide coverage, each of the antennas covering two sub-sectors of an area,

accepting traffic from remote stations within the area covered by the antennas,

providing communications through the antennas by using at least one radio channel of a channel set, the channel set being a set of at least one radio channel that is independent and free from interference from all other channels in the other channel sets,

balancing the traffic from certain users in one of the sub-sectors that is greater than the traffic from other users in an adjacent one of the sub-sectors, both the one sub-sector and the adjacent one of the sub-sectors being covered by a same one of the antennas, and

loading into memory in one of the remote stations the channel as a primary channel in the one channel set and a secondary channel in another channel set, tuning the one remote station to the primary channel and monitoring downstream signaling from the hub via one of the antennas, continuously checking if communications with the hub on the primary channel needs to change and if so tuning to the secondary channel to re-establish communications with the hub.

23. A method as in claim 22, further comprising sending a notification to the one remote station in response to the primary channel from the antenna becoming available again, responding to the notification to retune to the primary channel again to re-establish communications with the hub via the one antenna.

24. A method as in claim 22, wherein the area spans 120 degrees, each of the sub-sectors spanning 60 degrees.

25. An apparatus to balance traffic from users, comprising:

antennas arranged within an existing hub to provide coverage, each of the antennas covering two sub-sectors of an area, the antennas being configured to accept traffic from remote stations within the area covered by the antennas, the antennas being configured to provide communications through use of at least one radio channel of a channel set, the channel set being a set of one or more of the radio channels that is independent and free from interference from all other channels in the other channel sets, and the antennas being arranged to balance the traffic from certain users in one of the sub-sectors that is greater than the traffic from other users in an adjacent one of the sub-sectors, both the one sub-sector and the adjacent one of the sub-sectors being covered by a same one of the antennas, the remote stations being configured to dynamically re-tune from channels in one of the channel sets to channels in another of the channel sets in response to indication from the hub of current traffic conditions, the hub being configured to load balance as each of the remote stations comes within a coverage area of two channel sets by dynamically assigning the remote stations to one channel set or the other, depending on traffic conditions of the moment, to optimize use of both of the channel sets.

26. An apparatus to balance traffic from users, comprising:

antennas arranged within an existing hub to provide coverage, each of the antennas covering two sub-sectors of an area, the antennas being configured to accept traffic from remote stations within the area covered by the antennas, the antennas being configured to provide communications through use of at least one radio channel of a channel set, the channel set being a set of one or more of the radio channels that is independent and free from interference from all other channels in the other channel sets, and the antennas being arranged to balance the traffic from certain users in one of the sub-sectors that is greater than the traffic from other users in an adjacent one of the sub-sectors, both the one sub-sector and the adjacent one of the sub-sectors being covered by a same one of the antennas, the hub being configured to broadcast information about current traffic loading in the channel sets, each of the remote stations being configured to autonomously choose which of the channel sets to use based on the information.

27. An apparatus to balance traffic from users, comprising:

antennas arranged within an existing hub to provide coverage, each of the antennas covering two sub-sectors of an area, the antennas being configured to accept traffic from remote stations within the area covered by the antennas, the antennas being configured to provide communications through use of at least one radio channel of a channel set, the channel set being a set of one or more of the radio channels that is independent and free from interference from all other channels in the other channel sets, and the antennas being arranged to balance the traffic from certain users in one of the sub-sectors that is greater than the traffic from other users in an adjacent one of the sub-sectors, both the one sub-sector and the adjacent one of the sub-sectors being covered by a same one of the antennas, and

memory in one of the remote stations that is loaded with the channel as a primary channel in the one channel set and is loaded with a secondary channel in another channel set, the one remote station being configured to tune to the primary channel and to monitor downstream signaling from the hub via one of the antennas, the remote station being configured to continuously check if communications with the hub on the primary channel needs to change and if so to tune to the secondary channel to re-establish communications with the hub.

28. An apparatus to balance traffic from users, comprising:

antennas arranged within an existing hub to provide coverage, each of the antennas covering two sub-sectors of an area, the antennas being configured to accept traffic from remote stations within the area covered by the antennas, the antennas being configured to provide communications through use of at least one radio channel of a channel set, the channel set being a set of one or more of the radio channels that is independent and free from interference from all other channels in the other channel sets, and the antennas being arranged to balance the traffic from certain users in one of the sub-sectors that is greater than the traffic from other users in an adjacent one of the sub-sectors, both the one sub-sector and the adjacent one of the sub-sectors being covered by a same one of the antennas, the hub being configured to send a notification to the one remote station in response to the primary channel from the antenna becoming available again, the one remote station being configured to respond to the notification to retune to the primary channel again and re-establish communications with the hub via the one antenna.