METHOD AND SYSTEM FOR SUBCARRIER ALLOCATION IN RELAY ENHANCED CELLULAR SYSTEMS WITH RESOURCE REUSE

• US 20090161612A1
• Filed: 07/03/2008
• Published: 06/25/2009
• Est. Priority Date: 12/21/2007
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Liu, Yong, Ngo, Chiu
• Granted Patent: US 8,259,630 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0032 Distributed allocation, i.e. involving a plurality of allocating devices, each making partial allocation
• CPC Class Codes: H04L 5/0037 Inter-user or inter-terminal allocation
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 84/047 using dedicated repeater stations

Abstract

A method and system for assigning subcarrier frequency resource for a relay enhanced cellular communication system including a base station, one or more mobile stations and one or more relay stations, is provided. Subcarrier assignment involves allocating subcarriers to one or more relay communication links between the base station and relay stations, to accommodate minimum data rate requirements of the access communication links; and allocating subcarriers to one or more access communication links between relay stations and mobile stations to approximate the data rates achieved on the corresponding relay communication links, wherein allocating subcarriers to one or more access communication links includes reusing subcarriers among access communication links in different relay cells.

Claims

1. A method of allocating subcarrier frequency resource for a relay enhanced cellular communication system including a base station, one or more mobile stations and one or more relay stations, comprising:

assigning a set of subcarriers by;

allocating subcarriers to one or more relay communication links between the base station and relay stations, to accommodate minimum data rate requirements of the access communication links; and

allocating subcarriers to one or more access communication links between relay stations and mobile stations to approximate the data rates achieved on the corresponding relay communication links, wherein allocating subcarriers to one or more access communication links includes reusing subcarriers among access communication links in different relay cells.

2. The method of claim 1, wherein assigning subcarriers further includes:

allocating remaining subcarriers to access communication links and relay communication links to essentially maximize system-wide throughput, when all mobile stations meet their minimum data rate requirements;

wherein allocating subcarriers to access communication links includes reusing subcarriers among access communication links in different relay cells.

3. The method of claim 2, wherein the communication system comprises an Orthogonal Frequency Division Multiple Access relay enhanced cellular communication system.

4. The method of claim 2, wherein assigning a set of subcarriers further includes balancing subcarrier allocation for access communication links and relay communication links.

5. The method of claim 4, wherein assigning a set of subcarriers further includes balancing subcarrier allocation for access communication links and relay communication links, without adjusting allocation of subcarriers among access communication links in different relay cells.

6. The method of claim 2, wherein assigning a set of subcarriers includes assigning the set of subcarriers to one or more access communication links by:

detecting a serving station, among all under-assigned serving stations, with the least achievement-requirement data rate ratio on its access communication links, wherein a serving station is one of a base station or a relay station;

if the detected station is a base station, then allocating a subcarrier to the base station, wherein the allocated subcarrier cannot be reused by any relay station; and

if the detected station is a relay station, then allocating a subcarrier to the relay station, wherein the allocated subcarrier cannot be reused by the base station but may be reused by some other relay stations.

7. The method of claim 6, wherein assigning a set of subcarriers further includes:

if a subcarrier is allocated to an under-assigned relay station, the subcarrier can also be allocated to other under-assigned relay stations if the allocations can benefit the overall system throughput.

8. An apparatus for allocating subcarrier frequency resource for a relay enhanced cellular communication system including a base station, one or more mobile stations and one or more relay stations, comprising:

an optimization module configured for assigning a set of subcarriers by;

allocating subcarriers to one or more relay communication links between the base station and relay stations, to accommodate minimum data rate requirements of the access communication links; and

allocating subcarriers to one or more access communication links between relay stations and mobile stations to approximate the data rates achieved on the corresponding relay communication links, wherein allocating subcarriers to one or more access communication links includes reusing subcarriers among access communication links in different relay cells.

9. The apparatus of claim 8, wherein the optimization module is further configured for allocating remaining subcarriers to access communication links and relay communication links to essentially maximize system-wide throughput, when all mobile stations meet their minimum data rate requirements;

wherein allocating subcarriers to access communication links includes reusing subcarriers among access communication links in different relay cells.

10. The apparatus of claim 9, wherein the communication system comprises an Orthogonal Frequency Division Multiple Access relay enhanced cellular communication system.

11. The apparatus of claim 9, wherein the optimization module includes a balancing module configured Lor balancing subcarrier allocation for access communication links and relay communication links.

12. The apparatus of claim 11, wherein the balancing module is further configured for balancing subcarrier allocation for access communication links and relay communication links, without adjusting allocation of subcarriers among access communication links in different relay cells.

13. The apparatus of claim 9, wherein the optimization module includes an analysis module configured for detecting a serving station, among all under-assigned serving stations, with the least achievement-requirement data rate ratio on its access communication links, wherein a serving station is one of a base station or a relay station, such that if the detected station is a base station, then the balancing module allocates a subcarrier to the base station, wherein the allocated subcarrier cannot be reused by any relay station, and if the detected station is a relay station, then the balancing module allocates a subcarrier to the relay station, wherein the allocated subcarrier cannot be reused by the base station but may be reused by some other relay stations.

14. The apparatus of claim 13, wherein the balancing module is further configured such that if a subcarrier is allocated to an under-assigned relay station, the subcarrier can also be allocated to other under-assigned relay stations if the allocations can benefit the overall system throughput.

15. A relay enhanced cellular communication system, comprising:

a base station, one or more mobile stations and one or more relay stations;

a controller configured for allocating subcarrier frequency resources, the controller comprising an optimization module configured for assigning a set of subcarriers by;

allocating subcarriers to one or more relay communication links between the base station and relay stations, to meet minimum data rate requirements of the access communication links; and

allocating subcarriers to one or more access communication links between relay stations and mobile stations to approximate the data rates achieved on the corresponding relay communication links, wherein allocating subcarriers to one or more access communication links includes reusing subcarriers among access communication links in different relay cells.

16. The system of claim 15, wherein the optimization module is further configured for allocating remaining subcarriers to access communication links and relay communication links to essentially maximize system-wide throughput, when all mobile stations meet their minimum data rate requirements;

wherein allocating subcarriers to access communication links includes reusing subcarriers among access communication links in different relay cells.

17. The system of claim 16, wherein the communication system comprises an Orthogonal Frequency Division Multiple Access relay enhanced cellular communication system.

18. The system of claim 16, wherein the optimization module includes a balancing module configured for balancing subcarrier allocation for access communication links and relay communication links.

19. The system of claim 18, wherein the balancing module is further configured for balancing subcarrier allocation for access communication links and relay communication links, without adjusting allocation of subcarriers among access communication links in different relay cells.

20. The system of claim 17, wherein the optimization module includes an analysis module configured for detecting a serving station, among all under-assigned serving stations, with the least achievement-requirement data rate ratio on its access communication links, wherein a serving station is one of a base station or a relay station, such that if the detected station is a base station, then the balancing module allocates a subcarrier to the base station, wherein the allocated subcarrier cannot be reused by any relay station, and if the detected station is a relay station, then the balancing module allocates a subcarrier to the relay station, wherein the allocated subcarrier cannot be reused by the base station but may be reused by some other relay stations.

21. The system of claim 20, wherein the balancing module is further configured such that if a subcarrier is allocated to an under-assigned relay station, the subcarrier can also be allocated to other under-assigned relay stations if the allocations can benefit the overall system throughput.

22. The system of claim 15, wherein each relay station defines a relay cell.