Slot allocation, user grouping, and frame partition method for H-FDD systems

• US 8,238,367 B1
• Filed: 02/18/2009
• Issued: 08/07/2012
• Est. Priority Date: 03/27/2008
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell International Limited (Marvell Technology Group Limited)
• Inventors: Choi, Jihwan P., Lee, Jungwon
• Primary Examiner(s): Lai, Andrew
• Application Number:
  US12/388,302
• Time in Patent Office: 1,266 Days
• Field of Search: 370/230, 370/230.1, 370/234, 370/235, 370/280, 370/281, 370328-330, 370/336, 370/391, 370/468, 455/434, 455/450, 455/458, 455/561, 375/148
• US Class Current: 370/468
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0037 Inter-user or inter-terminal allocation
• CPC Class Codes: H04L 5/0064 Rate requirement of the data, e.g. scalable bandwidth, data priority
• CPC Class Codes: H04L 5/16 Half-duplex systems; Simplex/duplex switching; Transmission of break signals non-automatically inverting the direction of transmission

Abstract

Communication between a base station and remote stations is partitioned into frames, each including subframes having a number of slots that are allocated based on data rates for each remote station. For communication in a half-duplex mode, multiple subframes are used, each separated by a frame partition, such that a first user group of remote stations can receive down-link data in a first subframe while another user group of remote stations can transmit up-link data during that same subframe. For the next subframe, the converse happens. Slot allocation is achieved in such a half-duplex system based on weighted down-link and up-link data rates and without first or simultaneously determining user group allocation or frame partition, which are instead determined in response to the determined slot allocations for each remote station, e.g., using a linear programming technique.

Claims

1. A method for establishing duplex communication between a base station and a plurality of remote stations, wherein the duplex communication is partitioned into a series of frames, each frame including (i) a total integer number of slots, N, for down-link communication and (ii) a total integer number of slots, M, for up-link communication, the method comprising:

assigning, to each remote station, a respective down-link data rate and a respective up-link data rate for communication between that remote station and the base station;

providing for each remote station, using the base station, a respective down-link slot allocation for communication between that remote station and the base station, wherein the down-link slot allocation comprises a number of slots of the total slots N; and

providing for each remote station, using the base station, a respective up-link slot allocation for communication between that remote station and the at least one base station, wherein the up-link slot allocation comprises a number of slots of the total slots M,

wherein each remote station has a respective weighted down-link data rate associated with the respective down-link data rate assigned to that remote station, and each remote station has a respective weighted up-link data rate associated with the respective up-link data rate assigned to that remote station,

whereby a minimum of the respective weighted down-link data rates varies with the respective down-link slot allocation for each remote station, and a minimum of the respective weighted up-link data rates varies with the respective up-link slot allocation for each remote station, and

wherein the base station determines the respective down-link slot allocations of the plurality of remote stations and the respective up-link slot allocations of the plurality of remote stations so as to maximize the minimum of the weighted down-link data rates and of the weighted up-link data rates of the plurality of remote stations.

2. The method of claim 1, wherein the duplex communication is half-duplex communication wherein each frame comprises

a first subframe in which (i) a first user group of remote stations receives down-link data and (ii) a second user group of remote stations communicates up-link data, and

a second subframe in which (i) the first user group of remote stations transmit up-link data and (ii) the second user group of remote stations receives down-link data,

wherein each of the remote stations is assigned to either the first user group or the second user group in each frame, and wherein the first subframe is separated from the second subframe by a frame partition.

3. The method of claim 2, wherein the weighted down-link data rate of each remote station i is given by

4. The method of claim 2, wherein the weighted up-link data rate of each remote station i is given by

5. The method of claim 2, further comprising:

after providing the respective down-link slot allocation and the respective up-link slot allocation for each remote station, assigning, using the base station, each remote station to one of the first user group or the second user group.

6. The method of claim 5, further comprising:

determining, using the base station, a down-link frame partition for separating the first subframe and the second subframe for down-link communications, where the down-link frame partition depends on the respective down-link slot allocations and the respective up-link slot allocations to each remote station and depends on the assignment of each remote station to either the first user group or the second user group;

determining, using the base station, an up-link frame partition for separating the first subframe and the second subframe for up-link communications, where the up-link frame partition depends on the respective down-link slot allocations and the respective up-link slot allocations to each remote station and depends on the assignment of each remote station to either the first user group or the second user group; and

determining, using the base station, the frame partition from the down-link frame partition and the up-link frame partition.

7. The method of claim 6, wherein the base station determines the frame partition, x, as the geometric mean of the down-link frame partition, x_D, and the up-link frame partition, x_U, given by

8. The method of claim 6, further comprising re-allocating, using the base station, the down-link slot allocation and the up-link slot allocation to each remote station in response to the determination of the frame partition and after the assignment of each remote station to one of the first user group or the second user group.

9. The method of claim 6, further comprising minimizing the difference between the down-link frame partition and the up-link frame partition using mixed integer programming to determine the frame partition.

10. The method of claim 5, further comprising for a subsequent frame, reassigning, using the base station, at least one of the remote stations from the first user group to the second user group or vice versa.

11. The method of claim 1, wherein every one of the N slots for down-link communication and every one of the M slots for up-link communication are allocated to one of the plurality of remote stations in each frame.

12. The method of claim 1, wherein the duplex communication is performed by a WiMAX system operating in a half-frequency division duplex mode.

13. The method of claim 1, further comprising communicating data between the base station and at least one of the plurality of remote stations in accordance with the respective down-link and up-link slot allocations of that at least one of the plurality of remote stations.

14. A method for establishing duplex communication in a slot-based communication system, wherein communication is among a base station and a plurality of remote stations over a series of frames, each frame including (i) a total integer number of slots, N, for down-link communications and (ii) a total integer number of slots, M, for up-link communications, the method comprising:

identifying for each remote station of the plurality of remote stations, using the base station, a respective down-link data rate and a respective up-link data rate for communication between the remote station and the base station, wherein each remote station has (i) a respective down-link weighting factor indicative of a respective desired down-link quality of service level of the remote station and (ii) a respective up-link weighting factor indicative of a respective desired up-link quality of service level of the remote station, wherein each remote station has a respective weighted down-link data rate associated with (i) the respective down-link data rate and (ii) the respective down-link weighting factor, and wherein each remote station has a respective weighted up-link data rate associated with (i) the respective up-link data rate and (ii) the respective up-link weighting factor;

assigning to each of the plurality of remote stations, using the base station, (i) a respective down-link slot allocation for receiving down-link data from the base station during the frame and (ii) a respective up-link slot allocation for transmitting up-link data to the base station during the frame, so as to maximize the minimum of the respective weighted down-link data rates and of the respective weighted up-link data rates of the plurality of remote stations;

assigning, using the base station, each of the plurality of remote stations to one of a first user group and a second user group based on (i) the assigned respective down-link slot allocation and (ii) the assigned respective up-link slot allocation for each of the remote stations, wherein remote stations in the first user group are to receive down-link data in a first subframe and communicate up-link data in a second subframe, and wherein remote stations in the second user group are to communicate up-link data in the first subframe and receive down-link data in the second subframe; and

determining, using the base station, a frame partition separating the first subframe from the second subframe based on the assigned respective down-link slot allocation and the assigned respective up-link slot allocation for each of the remote stations.

15. The method of claim 14, wherein the weighted down-link data rate of each remote station i is given by

16. The method of claim 14, wherein the weighted up-link data rate of each remote station i is given by

17. The method of claim 14, wherein the respective down-link data rate and the respective up-link data rate are the same for each of the plurality of remote stations.

18. The method of claim 14, wherein the respective down-link data rate depends on the carrier-to-interference-and-noise-ratio for down-link data and is measured by the respective remote station and communicated from the respective remote station to the base station, and wherein the respective up-link data rate depends on the carrier-to-interference-and-noise-ratio for up-link data and is measured by the base station.

19. The method of claim 14, wherein all of the total number of slots, N, for down-link communications in a frame are assigned to remote stations by the base station, and wherein all of the total number of slots, M, for up-link communications in a frame are assigned to remote stations by the base station.

20. The method of claim 14, wherein the slot-based communication system is a WiMAX system wherein the WiMAX system communicates in a half-frequency division duplex mode.

21. The method of claim 14, further comprising communicating data between the base station and at least one of the plurality of remote stations in accordance with the respective down-link and up-link slot allocations of that remote station.

22. The method of claim 14, wherein determining the frame partition comprises:

determining, using the base station, a down-link frame partition for separating the first subframe and the second subframe for down-link communications;

determining, using the base station, an up-link frame partition for separating the first subframe and the second subframe for up-link communications; and

determining, using the base station, the frame partition from the down-link frame partition and the up-link frame partition.

23. The method of claim 22, wherein the base station determines the frame partition, x, as an arithmetic mean of the down-link frame partition, x_D, and the up-link frame partition, x_U, given by

24. The method of claim 14, further comprising re-assigning, using the base station, the down-link slot allocation and the up-link slot allocation to each remote station in response to the determination of the frame partition and user groupings prior to the base station communicating slot allocation data to the plurality of remote stations.