SEGMENTED TRANSMISSION FOR BROADCAST MESSAGES USING MULTIPLE ANTENNAS

• US 20100150129A1
• Filed: 12/17/2008
• Published: 06/17/2010
• Est. Priority Date: 12/17/2008
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Grabner, John, Wee, Daniel, Jin, Hang
• Granted Patent: US 8,416,802 B2
• Time in Patent Office: Days
• US Class Current: 370/343
• CPC Class Codes: H04W 72/30 Resource management for broadcast services

Abstract

Techniques are provided herein to segment subcarriers for broadcast transmission to one or more mobile stations. A broadcast message to be transmitted from a first device is generated. The broadcast message comprises a plurality of symbols and each symbol is to be transmitted at a different one of a plurality of frequency subcarriers. The plurality of subcarriers is divided into groups and each group of subcarriers is assigned to a corresponding one of a plurality of antennas of the first device. The groups of subcarriers are transmitted from corresponding ones of the plurality of antennas.

Claims

1. A method comprising:

generating a broadcast message to be transmitted from a first device, wherein the broadcast message comprises a plurality of symbols and each symbol is to be transmitted at a different one of a plurality of frequency subcarriers;

dividing the plurality of subcarriers into groups;

assigning each group of subcarriers to a corresponding one of a plurality of antennas of the first device; and

transmitting the groups of subcarriers from corresponding ones of the plurality of antennas.

2. The method of claim 1, wherein dividing comprises dividing the plurality of subcarriers into groups of contiguous subcarriers.

3. The method of claim 2, wherein assigning comprises assigning each group of subcarriers to a corresponding one of the plurality of antennas such that adjacent groups are assigned to geometrically adjacent ones of the plurality of antennas.

4. The method of claim 2, wherein assigning comprises assigning each group of subcarriers to a corresponding one of the plurality of antennas such that adjacent groups are assigned to non-geometrically adjacent ones of the plurality of antennas.

5. The method of claim 1, further comprising allocating first and second subsets of subcarriers of respective adjacent first and second groups at a boundary there between, and weighting the subcarriers in the first and second subsets so as to smooth any discontinuities that may occur at the boundary between the first and second groups.

6. The method of claim 5, wherein assigning comprises further assigning the subcarriers in the first subset to the antenna associated with the second group, and further assigning the subcarriers in the second subset to the antenna associated with the first group.

7. The method of claim 6, wherein weighting comprises weighting the subcarriers in the first and second subsets that are assigned to the antenna associated with the first group with a weighting function that decreases with subcarrier frequency.

8. The method of claim 6, wherein weighting comprises weighting the subcarriers in the first and second subsets that are assigned to the antenna associated with the second group with a weighting function that increases with subcarrier frequency.

9. An apparatus comprising:

a plurality of antennas;

a transmitter configured to transmit a broadcast message via respective ones of the plurality of antennas, wherein the broadcast message comprises a plurality of symbols and each symbol is to be transmitted at a different one of a plurality of frequency subcarriers;

a controller coupled to the transmitter and configured to;

divide the plurality of subcarriers into groups; and

assign each of the individual groups of subcarriers to a corresponding one of the plurality antennas for transmission.

10. The apparatus of claim 9, wherein the controller is configured to divide the plurality of subcarriers into groups of contiguous subcarriers.

11. The apparatus of claim 10, wherein the controller is configured to assign each group of subcarriers to a corresponding one of the plurality antennas such that adjacent groups are assigned to geometrically adjacent ones of the plurality of antennas.

12. The apparatus of claim 10, wherein the controller is configured to assign each group of subcarriers to a corresponding one of the plurality antennas such that adjacent groups are assigned to non-geometrically adjacent ones of the plurality of antennas.

13. The apparatus of claim 9, wherein the controller is further configured to allocate first and second subsets of subcarriers of respective adjacent first and second groups at a boundary there between, and to weight the subcarriers in the first and second subsets so as to smooth any discontinuities that may occur at the boundary between the first and second groups.

14. The apparatus of claim 13, wherein the controller is configured to further assign the subcarriers in the first subset to the antenna associated with the second group, and to further assign the subcarriers in the second subset to the antenna associated with the first group.

15. The apparatus of claim 14, wherein the controller is configured to weight the subcarriers in the first and second subsets that are assigned to the antenna associated with the first group by a weighting function that decreases with subcarrier frequency, and to weight the subcarriers in the first and second subsets that are assigned to the antenna associated with the second group by a weighting function that increases with subcarrier frequency.

16. Logic encoded in one or more tangible media for execution and when executed operable to:

generate a broadcast message to be transmitted from a first device, wherein the broadcast message comprises a plurality of symbols and each symbol is to be transmitted at a different one of a plurality of frequency subcarriers;

divide the plurality of subcarriers into groups; and

assign each group of subcarriers to a corresponding one of a plurality of antennas of the first device such that the groups of subcarriers are transmitted from corresponding ones of the plurality of antennas.

17. The logic of claim 16, wherein the logic that divides comprises logic that divides the plurality of subcarriers into groups of contiguous subcarriers.

18. The logic of claim 17, wherein the logic that assigns comprises logic that assigns each group of subcarriers to a corresponding one of the plurality of antennas such that adjacent groups are assigned to geometrically adjacent ones of the plurality of antennas.

19. The logic of claim 17, wherein the logic that assigns comprises logic that assigns each group of subcarriers to a corresponding one of the plurality of antennas such that adjacent groups are assigned to non-geometrically adjacent ones of the plurality of antennas.

20. The logic of claim 16, further comprising logic to allocate first and second subsets of subcarriers of respective adjacent first and second groups at a boundary there between, and to weight the subcarriers in the first and second subsets so as to smooth any discontinuities that may occur at the boundary between the first and second groups.

21. The logic of claim 20, wherein the logic that assigns further comprises logic to assign the subcarriers in the first subset to the antenna associated with the second group, and to further assign the subcarriers in the second subset to the antenna associated with the first group.

22. The logic of claim 21, wherein the logic that weights comprises logic to weight the subcarriers in the first and second subsets that are assigned to the antenna associated with the first group by a weighting function that decreases with subcarrier frequency, and to weight the subcarriers in the first and second subsets that are assigned to the antenna associated with the second group by a weighting function that increases with subcarrier frequency.