METHOD FOR TRANSMITTING AND RECEIVING CONTROL INFORMATION THROUGH PDCCH

• US 20090209247A1
• Filed: 10/15/2008
• Published: 08/20/2009
• Est. Priority Date: 02/19/2008
• Status: Active Grant

• Current Assignee: Optis Cellular Technology LLC (Brevet Capital)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Ahn, Joon Kui, Lee, Jung Hoon, Kim, Ki Jun, Noh, Yu Jin, Lee, Dae Won, Roh, Dong Wook
• Granted Patent: US 7,873,004 B2
• Time in Patent Office: Days
• US Class Current: 455/422.100
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01
• CPC Class Codes: H04L 27/2656 Frame synchronisation, e.g. packet synchronisation, time division duplex [TDD] switching point detection or subframe synchronisation
• CPC Class Codes: H04L 27/2666 Acquisition of further OFDM parameters, e.g. bandwidth, subcarrier spacing, or guard interval length
• 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 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 48/12 using downlink control channel
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 88/02 Terminal devices
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

A method for efficiently transmitting and receiving control information through a Physical Downlink Control Channel (PDCCH) is provided. When a User Equipment (UE) receives control information through a PDCCH, the received control information is set to be decoded in units of search spaces, each having a specific start position in the specific subframe. Here, a modulo operation according to a predetermined first constant value (D) is performed on an input value to calculate a first result value, and a modulo operation according to a predetermined first variable value (C) corresponding to the number of candidate start positions that can be used as the specific start position is performed on the calculated first result value to calculate a second result value and an index position corresponding to the second result value is used as the specific start position. Transmitting control information in this manner enables a plurality of UEs to efficiently receive PDCCHs without collisions.

Claims

1. A method for a User Equipment (UE) to receive control information through a Physical Downlink Control Channel (PDCCH), the method comprising:

receiving control information from a base station through the PDCCH in units of Control Channel Element (CCE) aggregations, each including at least one CCE in a control region of a specific subframe; and

decoding the received control information in units of search space in the specific subframe,

wherein a first resultant value is calculated by multiplying an input value by a predetermined second constant value (A), adding a predetermined third constant value (B), which result in a intermediate value, and performing a modulo operation according to a first constant value (D) on the intermediate value, and a modulo operation according to a predetermined first variable value (C) defined by the equation of

C=floor(N_CCE/L_CCE)

is performed on an index corresponding to the calculated first result value to calculate a second result value, and

wherein the search space starts with an index position corresponding to the second result value, and

where N_CCE represents the total number of CCEs in the specific subframe, and L_CCE is the number of CCEs included in the CCE aggregation, and floor(x) is a largest integer that is equal to or less than x.

2. The method according to claim 1, wherein the first constant value (D) is predetermined to be higher than the first variable value (C).

3. The method according to claim 1, wherein the input value for a “

k+1”

th subframe corresponds to the first result value for a “

k”

th subframe, where k is a non-negative integer.

4. The method according to claim 1, wherein an identification information value of the UE is used for the input value for a 1st subframe.

5. The method according to claim 1, wherein the first constant value (D), the second constant value (A), and the third constant value (B) are 65537, 39827, and 0, respectively.

6. The method according to any one of claims 1 to 5, wherein, when the specific subframe is the “

k”

th subframe, the first constant value is “

D”

, and the first constant value is “

C”

,

the search space starts with a start position Z_k in the “

k”

th subframe, the start position Z_k is set as an index position corresponding to a value determined by equations of Z_k=[(A·

y_k+B)modD]modC and y_k=(A·

y<sub>k−

1</sub>+B)modD, where A and B denote predetermined constant values and “

k”

denotes a subframe index.

7. The method according to claim 6, wherein the first constant value “

D”

is 65537, and

the predetermined constant values “

A” and

“

B”

are 39827 and 0, respectively.

8. The method according to claim 6, wherein the index position corresponding to the value determined by the equations corresponds to a start position of a CCE aggregation having the index corresponding to the value determined by the equations, under a condition in which indices are assigned on a CCE aggregation basis.

9. A method for a base station to transmit control information through a Physical Downlink Control Channel (PDCCH), the method comprising:

transmitting control information for a specific User Equipment (UE) through the PDCCH in units of Control Channel Element (CCE) aggregations, each including at least one CCE in a control region of a specific subframe,

wherein the control information for the specific UE is transmitted in units of search space in the specific subframe, and

wherein a first resultant value is calculated by multiplying an input value by a predetermined second constant value (A), adding a predetermined third constant value (B), which result in a intermediate value, and performing a modulo operation according to a first constant value (D) on the intermediate value, and a modulo operation according to a predetermined first variable value (C) defined by the equation of

C=floor(N_CCE/L_CCE)

is performed on an index corresponding to the calculated first result value to calculate a second result value, and

wherein the search space starts with an index position corresponding to the second result value, and

where N_CCE represents the total number of CCEs in the specific subframe, and L_CCE is the number of CCEs included in the CCE aggregation, and floor(x) is a largest integer that is equal to or less than x.

10. The method according to claim 9, wherein the first constant value (D) is predetermined to be higher than the first variable value (C).

11. The method according to claim 9, wherein the input value for a “

k+1”

th subframe corresponds to the first result value for a “

k”

th subframe, where “

k”

is a non-negative integer.

12. The method according to claim 11, wherein an identification information value of the UE is used for the input value for a 1st subframe.

13. The method according to claim 9, wherein the first constant value (D) is 65537 and the predetermined constant values (A) and (B) are 39827 and 0, respectively.

14. The method according to any one of claims 9 to 13, wherein, when the specific subframe is the “

k”

th subframe, the first constant value is “

D”

, and the first constant value is “

C”

,

the search space starts with a start position Z_k in the “

k”

th subframe, the start position Z_k is set as an index position corresponding to a value determined by equations of Z_k=[(A·

y_k+B)modD]modC and y_k=(A·

y<sub>k−

1</sub>+B)modD]modD, where A and B denote predetermined constant values and “

k”

denotes a subframe index.

15. The method according to claim 14, wherein the first constant value “

D”

is 65537, and

the predetermined constant values “

A” and

“

B”

are 39827 and 0, respectively.

16. The method according to claim 14, wherein the index position corresponding to the value determined by the equations corresponds to a start position of a CCE aggregation having the index corresponding to the value determined by the equations under a condition in which indices are assigned on a CCE aggregation basis.