Frequency hopping design for single carrier FDMA systems

• US 20060233124A1
• Filed: 08/22/2005
• Published: 10/19/2006
• Est. Priority Date: 04/19/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Palanki, Ravi
• Granted Patent: US 9,036,538 B2
• Time in Patent Office: Days
• US Class Current: 370/319
• CPC Class Codes: H04B 1/7143 Arrangements for generation of hop patterns

Abstract

Systems and methodologies are described that facilitate frequency hopping in a single carrier FDMA wireless environment by dynamically altering user offsets with time to obtain interference diversity. A channel tree can be utilized with nodes that are assigned values. User devices can be assigned to such nodes, a path between an assigned node and a root node in the channel tree can be evaluated, and a table lookup can be performed to determine an identity of a subcarrier set to assign to the user device assigned to a given node, as well as a number of subcarriers to be assigned to the user device. Additionally, node values can be dynamically varied during a communication event to alter path values and thus alter subcarrier set assignments.

Claims

1. A method of generating transmission symbols, comprising:

generating at least one single-carrier FDMA symbol;

assigning a set of subcarriers to transmit the at least one symbol;

generating at least one other single carrier FDMA symbol; and

varying subcarrier set assignments according to a predetermined pattern for transmission of the at least one other single-carrier FDMA symbol.

2. The method of claim 1, varying the subcarrier set assignments comprises changing an assignment of at least one offset in a predetermined set of offsets.

3. The method of claim 1, wherein the predetermined pattern is delineated by transmission of a number of frames.

4. The method of claim 1, wherein the predetermined pattern is delineated by expiration of a time period.

5. The method of claim 1, the subcarrier set assignments are varied at fixed intervals delineated by the transmission of a predetermined number of single-carrier FDMA symbols.

6. The method of claim 5, assigning subcarriers to a user device comprises:

generating a channel tree including a plurality of nodes;

assigning each child node a node value that represents a non-negative integer; and

assigning a user device to a node in the channel tree to define the subcarrier set assigned to the user device.

7. The method of claim 1, further comprising employing an IFDMA protocol to generate transmission symbols for transmission of the at least one single carrier FDMA symbol.

8. The method of claim 1, further comprising reading a channel tree from bottom to top to determine the subcarrier set.

9. The method of claim 8, further comprising reading a path in the channel tree from a user device-assigned node upward to a root node of the tree.

10. The method of claim 9, further comprising assessing value of nodes in the path, beginning with the user device-assigned node and ending with the first child node of the root node.

11. The method of claim 10, further comprising performing a table lookup to identify the subcarrier set corresponding to the value of the path from the user device-assigned node to the first child node of the root node, and assigning the user device the identified subcarrier set.

12. The method of claim 9, further comprising periodically varying node value assignments to alter user-device subcarrier set assignments.

13. The method of claim 9, wherein each node is assigned a non-binary value.

14. The method of claim 9, wherein each node is assigned a binary value.

15. The method of claim 1, further comprising employing an IFDMA protocol to generate transmission symbols and varying subcarrier set assignments upon transmission of each symbol when a subcarrier set assignment is of a size that warrants channel estimation over the entirety of available bandwidth.

16. The method of claim 1, further comprising employing an LFDMA protocol to generate transmission symbols for transmission of the at least one single carrier FDMA symbol.

17. The method of claim 1, wherein subcarrier assignments are varied as a function of at least one of sector identity and time.

55. The method of claim 1, further comprising employing an IFDMA protocol to generate transmission symbols and varying subcarrier set assignments upon transmission of each symbol when a subcarrier set assignment is of a size that warrants channel estimation over the entirety of available bandwidth.

56. The method of claim 1, further comprising employing an LFDMA protocol to generate transmission symbols for transmission of the at least one single carrier FDMA symbol.

18. An apparatus that facilitates frequency hopping for single carrier FDMA communication, comprising

a memory;

and

a processor coupled with the memory, the processor configured to assign an offset to a user device and to vary the offset for the user device according to a predetermined pattern.

19. The apparatus of claim 18, wherein the processor is further configured to utilize a channel tree with a plurality of nodes and to assign nodes in the channel tree to respective user devices.

20. The apparatus of claim 19, wherein the channel tree is a non-binary channel tree wherein each node has one or more child nodes.

21. The apparatus of claim 19, wherein each child node is assigned a non-binary value.

22. The apparatus of claim 19, wherein the processor is further configured to read the channel tree along a path from the node assigned to the user device to the first child node of a root node in the channel tree and evaluates a value for the path.

23. The apparatus of claim 22, wherein the processor is further configured to perform a table lookup to identify an offset corresponding to the value of the path from the node assigned to the user device to the root node and assigns to at least one of the user devices the identified offset.

24. The apparatus of claim 23, wherein the user device is assigned an offset corresponding to the value of the path to the node assigned to the user device from the root node.

25. The apparatus of claim 24, wherein the processor is further configured to periodically permute node value assignments of one or more nodes in the channel tree to change the offset of the user device by changing the value of the path from the user-assigned node to the root node.

26. The apparatus of claim 19, wherein the processor is further configured to read the channel tree along a path from the first child node of a root node to a node assigned to the user device in the channel tree and evaluates a value for the path.

27. The apparatus of claim 19, wherein the channel tree is a non-binary channel tree having a plurality of nodes, each of which is assigned a value that represents a non-negative integer.

28. The apparatus of claim 19, wherein the processor is further configured to read the channel tree in an upward direction to determine an offset assignment for a user device employing an IFDMA communication protocol and in a downward direction to determine an offset assignment for a user device employing an LFDMA communication protocol.

29. The apparatus of claim 19, wherein the processor is further configured to periodically permute offset assignments between respective user devices by altering node value assignments.

30. The apparatus of claim 18, wherein the processor is further configured to employ a symbol rate hopping technique to alter node value assignments of one or more nodes upon transmission of each symbol by the user device.

31. The apparatus of claim 30, the frequency hopping component is configured to employ a block hopping technique to alter node value assignments of one or more nodes upon transmission of a block of more than one symbol by the user device.

32. An apparatus comprising:

means for generating at least one single-carrier FDMA symbol;

means for assigning a set of subcarriers to transmit the at least one symbol;

means for generating at least one other single carrier FDMA symbol; and

means for varying subcarrier set assignments, according to a predetermined pattern for transmission of the at least one other single-carrier FDMA symbol.

33. The apparatus of claim 32, the means for assigning comprises means for allocating a node in a channel tree to the user device and means for assigning a value to each node in the channel tree.

34. The apparatus of claim 33, the means for assigning further comprises means for reading a path in the channel tree from an allocated user node to a root node to determine a value for nodes in the path that identifies the set of subcarriers to assign to the user device and a number of subcarriers to include in the set.

35. The apparatus of claim 34, the means for varying periodically alters values assigned to one or more nodes in the channel tree to vary the value of the path between the allocated user node and the root node.

36. The apparatus of claim 35, the means for assigning assigns a new set of subcarriers associated with the varied value of the path from the allocated user node to the root node.

37. The apparatus of claim 36, the means for varying alters node values upon transmission of the at least one single carrier FDMA symbol.

38. A computer-readable medium having stored thereon computer-executable instructions for:

assigning an offset-related entity to a user device; and

periodically varying the offset for the user device based at least in part on the assigned entity.

39. The computer-readable medium of claim 38, further comprising instructions for:

assigning a value to each node of a channel tree;

allocating a node to at least one user device to assign a subcarrier set to the at least one user device; and

permuting node values according to a pattern to change the subcarrier set assigned to the at least one user device.

40. The computer-readable medium of claim 39, further comprising instructions for reading a path between the node allocated to the at least one user device and a root node in the channel tree.

41. The computer-readable medium of claim 40, further comprising instructions for determining a subcarrier set to assign to the at least one user device based at least in part on a path value derived from the values of nodes in the path.

42. The computer-readable medium of claim 40, further comprising instructions for determining a number of subcarriers to assign to the at least one user device based at least in part on the number of nodes in the path, inclusive of the root node and the node allocated to the at least one user device.

43. The computer readable-medium of claim 38, wherein the instruction to permute comprises instructions for computing an offset for the user device based at least in part on the assigned entity.

44. A wireless communication device comprising:

a memory comprising information corresponding to a plurality of offset assignments for transmission of single-carrier FDMA symbols; and

a processor coupled with the memory, the processor configured to vary the offset assignments according to a predetermined pattern based upon the information.

45. The wireless communication device of claim 44, wherein the information corresponds to values for nodes of a channel tree.

46. The wireless communication device of claim 45, wherein the nodes correspond to root nodes and child nodes.

47. The wireless communication device of claim 45, wherein the channel tree is a non-binary channel tree wherein each node has one or more child nodes.

48. The wireless communication device of claim 45, wherein values correspond to values generated by reading the channel tree along a path from the node assigned to the user device to the first child node of a root node in the channel tree and evaluates a value for the path.

49. The wireless communication device of claim 45, wherein the information comprises a look-up table.

50. A method of generating transmission symbols, comprising:

generating at least one single-carrier FDMA symbol at a user device;

assigning a set of subcarriers to transmit the at least one symbol based upon user information at the user device;

generating at least one other single carrier FDMA symbol at the user device; and

altering subcarrier set assignments according to a predetermined offset change based upon the information for transmission of the at least one other single-carrier FDMA symbol.

51. The method of claim 50, further comprising reading a value from a look-up table and wherein altering the subcarrier set assignments comprises changing the assignment by altering the current subcarrier set location by the value.

52. The method of claim 50, wherein the predetermined pattern is delineated by transmission of a number of frames.

53. The method of claim 50, wherein the predetermined pattern is delineated by expiration of a time period.

54. The method of claim 50, the subcarrier set assignments are varied at fixed intervals delineated by the transmission of a predetermined number of single-carrier FDMA symbols.