HANDLING UPLINK GRANT IN RANDOM ACCESS RESPONSE

• US 20100040001A1
• Filed: 07/10/2009
• Published: 02/18/2010
• Est. Priority Date: 08/12/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Montojo, Juan, Meylan, Arnaud
• Granted Patent: US 8,780,816 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04W 72/04 Wireless resource allocation
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 74/004 in the uplink, i.e. towards network
• CPC Class Codes: H04W 74/006 in the downlink, i.e. towards the terminal
• CPC Class Codes: H04W 74/0833 Random access procedures, e.g. with 4-step access

Abstract

A wireless communication system provides for a random access channel (RACH) procedure for user equipment (UE) to request access to an uplink channel. From a physical layer perspective, an evolved Base Station (eNB) responds with a random access preamble and a random access response (RAR) of a fixed length message, such as 21 bits or 20 bits with a reserved bit for future extensions. In answer to a need that exists for an RAR to accommodate variations in system bandwidth, an approach to encoding a truncated resource block (RB) assignment of the RAR in manner in which the UE can interpret the RAR without loss of information. Thereby, needs for achieving RACH procedures and existing channel resources can be realized.

Claims

1. A method for decoding a grant, comprising:

receiving a grant on a downlink channel;

detecting a portion of the grant whose length was adjusted; and

decoding a resource block assignment based upon the number of uplink resource blocks.

2. The method of claim 1, further comprising detecting the adjusted length portion of the grant comprising a cropped or expanded resource block assignment in accordance with system bandwidth.

3. The method of claim 2, further comprising interpreting a truncated resource block assignment given that a number of uplink resource blocks (N_rb^ul) is the number of uplink resource blocks by,

determining if N_rb^ul<

=32, then truncating a fixed size resource block assignment to its b least significant bits where

b=ceiling log₂((N_rb^ul*N_rb^ul+1)/2); and

interpreting the truncated resource block assignment according to the rules for a regular physical downlink control channel (PDCCH) grant.

4. The method of claim 3, further comprising interpreting the truncated resource block assignment by,

determining if N_rb^ul>

32, then concatenating b bits with value set to ‘

0’

as most significant bits with a fixed size resource block assignment, where

b=ceiling log 2((N_rbul*N_rb^ul+1)/2)−

10; and

interpreting expanded resource block assignment according to the rules for a regular PDCCH grant.

5. The method of claim 1, further comprising interpreting further truncation of the grant by detecting an indication in a physical layer that a new transmission is requested when an uplink grant is received in the random access response.

6. The method of claim 5, further comprising detecting on a physical layer that a new transmission is requested when an uplink grant is received in RAR.

7. The method of claim 1, further comprising interpreting the adjustable-length grant to satisfy a fixed-sized format of a 1-bit frequency hopping flag, a 10-bit fixed size resource block assignment, a five-bit modulation and coding scheme, a four-bit total power control for scheduled physical uplink (PUSCH), a a-bit uplink delay, and a 1-bit channel quality indication (CQI) request.

8. The method of claim 1, further comprising:

receiving resource allocation information indicated as a set of contiguously allocated localized virtual resource blocks (VRBs) or distributed VRBs depending on the setting of a 1-bit flag carried on the associated physical downlink control channel (PDCCH), wherein localized VRB allocations vary from a single VRB up to a maximum number of VRBs spanning the system bandwidth, and wherein distributed VRB allocations vary from a single VRB up to is the number of downlink resource blocks (N_rb^dl) VRBs if N_rb^dl is 6-49 and vary from a single VRB up to 16 if N_rb^dl is 50-110;

determining resource indication value RIV=N_RB^DL(L_CRBs−

1)+RB_start if (L_CRBs−

1)≦

[N_RB^DL/2] else RIV=N_RB^DL(N_RB^DL−

L_CRBs+1)+(N_RB^DL−

1−

RB_start), given a resource allocation field consists of a resource indication value (RIV) corresponding to a starting resource block (RB_start) and a length in terms of contiguously allocated resource blocks (L_CRBs);

in response to determining that N_RB^UL≦

44, interpreting a fixed size resource block assignment as having been truncated to its b least significant bits, where b=┌

log₂(N_RB^UL·

(N_RB^UL+1)/2)┐

, wherein the truncated resource block assignment is interpreted according to the rules for a regular downlink control information (DCI) format 0; and

in response to determining that N_RB^UL>

44, interpreting a fixed size resource block assignment as having been expanded with pre-appended b bits with value set to ‘

0’

, where b=(┌

log₂(N_RB^UL·

(N_RB^UL+1)/2)┐

−

10), wherein interpreting the expanded resource block assignment is performed according to the rules for a regular DCI format 0.

9. The method of claim 8, further comprising interpreting a truncated modulation and coding scheme (MCS) as indices 0-15 omitting a highest modulation.

10. At least one processor for decoding a grant, comprising:

a first module for receiving a grant on a downlink channel;

a second module for detecting a portion of the grant whose length was adjusted; and

a third module for decoding a resource block assignment based upon the number of uplink resource blocks.

11. A computer program product for decoding a grant, comprising:

a computer-readable storage medium comprising,

a first set of codes for causing a computer to receive a grant on a downlink channel;

a second set of codes for causing the computer to detect a portion of the grant whose length was adjusted; and

a third set of codes for causing the computer to decode a resource block assignment based upon the number of uplink resource blocks.

12. An apparatus for decoding a grant, comprising:

means for receiving a grant on a downlink channel;

means for detecting a portion of the grant whose length was adjusted; and

means for decoding a resource block assignment based upon the number of uplink resource blocks.

13. An apparatus for decoding a grant, comprising:

a receiver for receiving a grant on a downlink channel;

a computing platform for detecting a portion of the grant whose length was adjusted; and

the computing platform for decoding a resource block assignment based upon the number of uplink resource blocks.

14. The apparatus of claim 13, further comprising the computing platform for detecting the adjusted length portion of the grant comprising a cropped or expanded resource block assignment in accordance with system bandwidth.

15. The apparatus of claim 14, further comprising the computing platform for interpreting a truncated resource block assignment given that a number of uplink resource blocks (N_rb^ul) is the number of uplink resource blocks by, determining if N_rb^ul<

=32, then truncating a resource block assignment to its b least significant bits where b=ceiling log₂((N_rb^ul*N_rb^ul+1)/2); and

interpreting the truncated resource block assignment according to the rules for a regular physical downlink control channel (PDCCH) grant.

16. The apparatus of claim 15, further comprising the computing platform for interpreting the truncated resource block assignment by,

determining if N_rb^ul>

32, then concatenating b bits with value set to ‘

0’

as most significant bits with a resource block assignment, where

b=ceiling log 2((N_rb^ul*N_rb^ul+1)/2)−

10; and

interpreting expanded resource block assignment according to the rules for a regular PDCCH grant.

17. The apparatus of claim 13, further comprising the computing platform for interpreting further truncation of the grant by detecting an indication in a physical layer that a new transmission is requested when an uplink grant is received in the random access response.

18. The apparatus of claim 17, further comprising the computing platform for detecting on a physical layer that a new transmission is requested when an uplink grant is received in RAR.

19. The apparatus of claim 13, further comprising the computing platform for interpreting the adjustable-length grant to satisfy a format of a 1-bit frequency hopping flag, a 10-bit resource block assignment, a five-bit modulation and coding scheme, a four-bit total power control for scheduled physical uplink (PUSCH), a a-bit uplink delay, and a 1-bit channel quality indication (CQI) request.

20. The apparatus of claim 13, further comprising:

the receiver for receiving resource allocation information indicated as a set of contiguously allocated localized virtual resource blocks (VRBs) or distributed VRBs depending on the setting of a 1-bit flag carried on the associated physical downlink control channel (PDCCH), wherein localized VRB allocations vary from a single VRB up to a maximum number of VRBs spanning the system bandwidth, and wherein distributed VRB allocations vary from a single VRB up to is the number of downlink resource blocks (N_rb^dl) VRBs if N_rb^dl is 6-49 and vary from a single VRB up to 16 if N_rb^dl is 50-110;

the computing platform for determining resource indication value RIV=N_RB^DL(L_CRBs−

1)+RB_start if (L_CRBs−

1)≦

[N_RB^DL/2] else RIV=N_RB^DL(N_RB^DL−

L_CRBs+1)+(N_RB^DL−

1−

RB_start), given a resource allocation field consists of a resource indication value (RIV) corresponding to a starting resource block (RB_start) and a length in terms of contiguously allocated resource blocks (L_CRBs);

the computing platform for, in response to determining that H_RB^UL≦

44, interpreting a resource block assignment as having been truncated to its b least significant bits, where b=┌

log₂(N_RB^UL·

(N_RB^UL+1)/2)┐

, wherein the truncated resource block assignment is interpreted according to the rules for a regular downlink control information (DCI) format 0; and

the computing platform for, in response to determining that N_RB^UL>

44, interpreting a resource block assignment as having been expanded with pre-appended b bits with value set to ‘

0’

, where b=(┌

log₂(N_RB^UL·

(N_RB^UL+1)/2)┐

−

10), wherein interpreting the expanded resource block assignment is performed according to the rules for a regular DCI format 0.

21. The apparatus of claim 20, further comprising the computing platform for interpreting a truncated modulation and coding scheme (MCS) as indices 0-15 omitting a highest modulation.

22. A method for encoding a grant, comprising:

determining a number of uplink resource blocks and a length adjustment based upon system bandwidth for the grant;

encoding the resource block assignment based upon the number of uplink resource blocks to achieve the determined length adjustment; and

transmitting a grant on a downlink channel.

23. The method of claim 22, further comprising adjusting the length of the grant by cropping or expanding resource block assignment in accordance with system bandwidth.

24. The method of claim 23, further comprising encoding a truncated resource block assignment given that a number of uplink resource blocks (N_rb^ul) is the number of uplink resource blocks by,

determining if N_rb^ul<

=32, then truncating a resource block assignment to its b least significant bits where b=ceiling log₂((N_rb^ul*N_rb^ul+1)/2); and

interpreting the truncated resource block assignment according to the rules for a regular physical downlink control channel (PDCCH) grant.

25. The method of claim 24, further comprising encoding the truncated resource block assignment by,

determining if N_rb^ul>

32, then concatenating b bits with value set to ‘

0’

as most significant bits with a resource block assignment, where

b=ceiling log 2((N_rb^ul*N_rb^ul+1)/2)−

10; and

interpreting expanded resource block assignment according to the rules for a regular PDCCH grant.

26. The method of claim 22, further comprising truncating further the grant by transmitting an indication in a physical layer that a new transmission is requested when an uplink grant is transmitted in the random access response.

27. The method of claim 26, further comprising transmitting on a physical layer that a new transmission is requested when an uplink grant is received in RAR.

28. The method of claim 22, further comprising encoding the adjustable-length grant to satisfy a format of a 1-bit frequency hopping flag, a 10-bit resource block assignment, a five-bit modulation and coding scheme, a four-bit total power control for scheduled physical uplink (PUSCH), a a-bit uplink delay, and a 1-bit channel quality indication (CQI) request.

29. The method of claim 22, further comprising:

transmitting resource allocation information indicated as a set of contiguously allocated localized virtual resource blocks (VRBs) or distributed VRBs depending on the setting of a 1-bit flag carried on the associated physical downlink control channel (PDCCH), wherein localized VRB allocations vary from a single VRB up to a maximum number of VRBs spanning the system bandwidth, and wherein distributed VRB allocations vary from a single VRB up to is the number of downlink resource blocks (N_rb^dl) VRBs if N_rb^dl is 6-49 and vary from a single VRB up to 16 if N_rb^dl is 50-110;

determining resource indication value RIV=N_RB^DL(L_CRBs−

1)+RB_start if (L_CRBs−

1)≦

[N_RB^DL/2] else RIV=N_RB^DL(N_RB^DL−

L_CRBs+1)+(N_RB^DL−

1−

RB_start), given a resource allocation field consists of a resource indication value (RIV) corresponding to a starting resource block (RB_start) and a length in terms of contiguously allocated resource blocks (L_CRBs);

in response to determining that N_RB^UL≦

44, adjusting a resource block assignment to its b least significant bits, where b=┌

log₂(N_RB^UL·

(N_RB^UL+1)/2)┐

, wherein the truncated resource block assignment is interpreted according to the rules for a regular downlink control information (DCI) format 0; and

in response to determining that N_RB^UL>

44, adjusting a resource block assignment by expanding with pre-appended b bits with value set to ‘

0’

, where b=(┌

log₂(N_RB^UL·

(N_RB^UL+1)/2)┐

−

10), wherein interpreting the expanded resource block assignment is performed according to the rules for a regular DCI format 0.

30. The method of claim 29, further comprising truncating modulation and coding scheme (MCS) as indices 0-15 omitting a highest modulation.

31. At least one processor for encoding a grant, comprising:

a first module for determining a number of uplink resource blocks and a length adjustment based upon system bandwidth for the grant;

a second module for encoding the resource block assignment based upon the number of uplink resource blocks to achieve the determined length adjustment; and

a third module for transmitting a grant on a downlink channel.

32. A computer program product for encoding a grant, comprising:

a computer-readable storage medium comprising,

a first set of codes for causing a computer to determine a number of uplink resource blocks and a length adjustment based upon system bandwidth for the grant;

a second set of codes for causing the computer to encode the resource block assignment based upon the number of uplink resource blocks to achieve the determined length adjustment; and

a third set of codes for causing the computer to transmit a grant on a downlink channel.

33. An apparatus for encoding a grant, comprising:

means for determining a number of uplink resource blocks and a length adjustment based upon system bandwidth for the grant;

means for encoding the resource block assignment based upon the number of uplink resource blocks to achieve the determined length adjustment; and

means for transmitting a grant on a downlink channel.

34. An apparatus for encoding a grant, comprising:

a computing platform for determining a number of uplink resource blocks and a length adjustment based upon system bandwidth for the grant;

the computing platform for encoding the resource block assignment based upon the number of uplink resource blocks to achieve the determined length adjustment; and

a transmitter for transmitting a grant on a downlink channel.

35. The apparatus of claim 34, further comprising the computing platform for adjusting the length of the grant by cropping or expanding resource block assignment in accordance with system bandwidth.

36. The apparatus of claim 35, further comprising the computing platform for encoding a truncated resource block assignment given that a number of uplink resource blocks (N_rb^ul) is the number of uplink resource blocks by,

determining if N_rb^ul<

=32, then truncating a resource block assignment to its b least significant bits where b=ceiling log₂((N_rb^ul*N_rb^ul+1)/2); and

interpreting the truncated resource block assignment according to the rules for a regular physical downlink control channel (PDCCH) grant.

37. The apparatus of claim 36, further comprising the computing platform for encoding the truncated resource block assignment by,

determining if N_rb^ul>

32, then concatenating b bits with value set to ‘

0’

as most significant bits with a resource block assignment, where

b=ceiling log 2((N_rb^ul*N_rb^ul+1)/2)−

10; and

interpreting expanded resource block assignment according to the rules for a regular PDCCH grant.

38. The apparatus of claim 34, further comprising the computing platform for truncating further the grant by transmitting an indication in a physical layer that a new transmission is requested when an uplink grant is transmitted in the random access response.

39. The apparatus of claim 38, further comprising the computing platform for transmitting on a physical layer that a new transmission is requested when an uplink grant is received in RAR.

40. The apparatus of claim 34, further comprising the computing platform for encoding the adjustable-length grant to satisfy a format of a 1-bit frequency hopping flag, a 10-bit resource block assignment, a five-bit modulation and coding scheme, a four-bit total power control for scheduled physical uplink (PUSCH), a a-bit uplink delay, and a 1-bit channel quality indication (CQI) request.

41. The apparatus of claim 34, further comprising:

the transmitter for transmitting resource allocation information indicated as a set of contiguously allocated localized virtual resource blocks (VRBs) or distributed VRBs depending on the setting of a 1-bit flag carried on the associated physical downlink control channel (PDCCH), wherein localized VRB allocations vary from a single VRB up to a maximum number of VRBs spanning the system bandwidth, and wherein distributed VRB allocations vary from a single VRB up to is the number of downlink resource blocks (N_rb^dl) VRBs if N_rb^dl is 6-49 and vary from a single VRB up to 16 if N_rb^dl is 50-110;

the computing platform for determining resource indication value RIV=N_RB^DL(L_CRBs−

1)+RB_start if (L_CRBs−

1)≦

[N_RB^DL/2] else RIV=N_RB^DL(N_RB^DL−

L_CRBs+1)+(N_RB^DL−

1−

RB_start), given a resource allocation field consists of a resource indication value (RIV) corresponding to a starting resource block (RB_start) and a length in terms of contiguously allocated resource blocks (L_CRBs);

the computing platform for, in response to determining that N_RB^UL≦

44, adjusting a resource block assignment to its b least significant bits, where b=┌

log₂(N_RB^UL·

(N_RB^UL+1)/2)┐

, wherein the truncated resource block assignment is interpreted according to the rules for a regular downlink control information (DCI) format 0; and

the computing platform for, in response to determining that N_RB^UL>

44, adjusting a resource block assignment by expanding with pre-appended b bits with value set to ‘

0’

, where b=(┌

log₂(N_RB^UL·

(N_RB^UL+1)/2)┐

−

10), wherein interpreting the expanded resource block assignment is performed according to the rules for a regular DCI format 0.

42. The apparatus of claim 41, further comprising the computing platform for truncating modulation and coding scheme (MCS) as indices 0-15 omitting a highest modulation.