Monitoring a control channel for carrier aggregation

• US 8,983,516 B2
• Filed: 08/19/2013
• Issued: 03/17/2015
• Est. Priority Date: 05/03/2010
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Intel Corporation
• Inventors: Wang, Ping
• Primary Examiner(s): Safaipour, Bobbak
• Application Number:
  US13/969,966
• Publication Number:
  US 20130336263A1
• Time in Patent Office: 575 Days
• Field of Search: 455/509, 455/515, 455/522, 455/507, 370/328, 370/329, 370/252, 370/241
• US Class Current: 455/515
• CPC Class Codes: H04L 1/1614 using bitmaps
• CPC Class Codes: H04L 47/11 Identifying congestion
• CPC Class Codes: H04L 47/283 in response to processing delays, e.g. caused by jitter or round trip time [RTT]
• CPC Class Codes: H04L 47/30 in combination with information about buffer occupancy at either end or at transit nodes
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04L 5/0016 Time-frequency-code
• CPC Class Codes: H04L 5/003 Arrangements for allocating sub-channels of the transmission path
• CPC Class Codes: H04L 5/0032 Distributed allocation, i.e. involving a plurality of allocating devices, each making partial allocation
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 5/0064 Rate requirement of the data, e.g. scalable bandwidth, data priority
• CPC Class Codes: H04L 5/0094 Indication of how sub-channels of the path are allocated
• CPC Class Codes: H04W 28/02 Traffic management, e.g. flow control or congestion control
• CPC Class Codes: H04W 28/12 using signalling between network elements
• CPC Class Codes: H04W 36/22 for handling the traffic
• CPC Class Codes: H04W 4/06 Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
• CPC Class Codes: H04W 72/04 Wireless resource allocation
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/23 : in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/52 : based on load
• CPC Class Codes: H04W 76/27 : Transitions between radio resource control [RRC] states
• CPC Class Codes: H04W 8/04 : Registration at HLR or HSS [Home Subscriber Server]
• CPC Class Codes: Y02D 30/00 : Reducing energy consumption in communication networks
• CPC Class Codes: Y02D 30/70 : in wireless communication networks

Abstract

Technology for allocating a physical downlink control channel (PDCCH) to reduce a number of PDCCH candidates in a search space for carrier aggregation on a user equipment (UE) is disclosed. The UE is configured with a carrier information field (CIF) having a communications processor to determine physical downlink control channel (PDCCH) assignments of a cellular communication system. The communication processor can monitor in a cell a set of PDCCH candidates defined in a search space S_k^(L) at an aggregation level Lε{1,2,4,8} for a subframe (k) which includes a set of control channel elements (CCEs) and to decode a PDCCH of the set of PDCCH candidates according to downlink control information (DCI).

Claims

1. An apparatus, comprising:

a user equipment (UE) configured with a carrier information field (CIF) and having a communications processor to determine physical downlink control channel (PDCCH) assignments of a cellular communication system, wherein the communication processor is to monitor in a cell a set of PDCCH candidates defined in a search space S_k^(L) at an aggregation level Lε

{1,2,4,8} for a subframe (k) which includes a set of control channel elements (CCEs) and to decode a PDCCH of the set of PDCCH candidates according to downlink control information (DCI).

2. The apparatus of claim 1, wherein the search space S_k^(L) is defined by S_k^(L)=L·

{(Y_k+m)mod └

N_CCE,k/L┘

}+i wherein N_CCE,k is the total number of CCEs in a k^th subframe (kε

{0,1,2,3,4,5,6,7,8,9}), i=0, . . . , L−

1 is a constant, m=0, . . . , M^(L)−

1, and M^(L) is the number of PDCCH candidates to monitor in a given search space.

3. The apparatus of claim 2, wherein Y_k is defined by Y_k=(A·

Y_k-1)mod D wherein, Y_k-1=n_RNTI≠

0, n_RNTI≠

0, n_RNTI is a Radio Network Temporary Identifier (RNTI) number assigned to the UE, A=39827, D=65537, k=└

n_s/2┘

, and n_s (nε

{0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19}) is the slot number within a radio frame.

4. The apparatus of claim 1, wherein the communication processor is programmed to:

search for a selected component carrier'"'"'s (CC'"'"'s) downlink control information (DCI) in the search space S_k^(L) by identifying a starting control channel elements (CCE) location based on a selected CC'"'"'s carrier index and the aggregation level L until a validly decoded PDCCH candidate is decoded; and

to obtain the selected CC'"'"'s DCI from the validly decoded PDCCH candidate.

5. The apparatus of claim 1, wherein a PDCCH candidate includes a cyclic redundancy check (CRC) which is masked by a Cell-Radio Network Temporary Identifier (C-RNTI).

6. The apparatus of claim 1, wherein the DCI format includes the CIF.

7. A method for monitoring physical downlink control channel (PDCCH) assignments by a user equipment (UE) configured with a carrier information field (CIF) and, the method comprising:

monitoring in a cell a set of PDCCH candidates defined in a search space S_k^(L) at an aggregation level Lε

{1,2,4,8} for a subframe (k) which includes a set of control channel elements (CCEs) and to decode a PDCCH of the set of PDCCH candidates according to downlink control information (DCI).

8. The method of claim 7, wherein the search space S_k^(L) is defined by S_k^(L)=L·

{(Y_k+m)mod └

N_CCE,k/L┘

}+i wherein N_CCE,k is the total number of CCEs in a k^th subframe (kε

{0,1,2,3,4,5,6,7,8,9}), i=0, . . . , L−

1 is a constant, m=0, . . . , M^(L)−

1, and M^(L) is the number of PDCCH candidates to monitor in a given search space.

9. The method of claim 8, wherein Y_k is defined by Y_k=(A·

Y_k-1)mod D wherein, Y_k-1=n_RNTI≠

0, n_RNTI is a Radio Network Temporary Identifier (RNTI) number assigned to the UE, A=39827, D=65537, k=└

n_s/2┘

, and n_s (nε

{0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19}) is the slot number within a radio frame.

10. The method of claim 7, wherein monitoring comprising:

searching for a selected component carrier'"'"'s (CC'"'"'s) downlink control information (DCI) in the search space S_k^(L) by identifying a starting control channel elements (CCE) location based on a selected CC'"'"'s carrier index and the aggregation level L until a validly decoded PDCCH candidate is decoded; and

obtaining the selected CC'"'"'s DCI from the validly decoded PDCCH candidate.

11. The method of claim 10, wherein a PDCCH candidate includes a cyclic redundancy check (CRC) which is masked by a Cell-Radio Network Temporary Identifier (C-RNTI).

12. The method of claim 11, wherein the DCI format includes the CIF.

13. A communication system, comprising:

an evolved Node B (eNB) configured with a carrier information field (CIF) operable in a long term evolution (LTE) communication system comprises a transmitter operably coupled to one or more antenna ports and capable of assigning a set of PDCCH candidates to a user equipment (UE), the set of PDCCH candidates are defined in a search space S_k^(L) at an aggregation level Lε

{1,2,4,8} for a subframe k which includes a set of control channel elements (CCEs) and wherein, the UE is configured to monitor the set of PDCCH and to decode a PDCCH of the set of PDCCH candidates according to downlink control information (DCI).

14. The communication system of claim 13, wherein the search space S_k^(L) is defined by S_k^(L)=L·

{(Y_k+m)mod └

N_CCE,k/L┘

}+i wherein N_CCE,k is the total number of CCEs in a k^th subframe (kε

{0,1,2,3,4,5,6,7,8,9}), i=0, . . . , L−

1 is a constant, m=0, . . . , M^(L)−

1, and M^(L) is the number of PDCCH candidates to monitor in a given search space.

15. The communication system of claim 14, wherein Y_k is defined by Y_k=(A·

Y_k-1)mod D wherein, Y_k-1=n_RNTI≠

0, n_RNTI is a Radio Network Temporary Identifier (RNTI) number assigned to the UE, A=39827, D=65537, k=└

n_s/2┘

, and n_s (nε

{0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19}) is the slot number within a radio frame.

16. The communication system of claim 13, wherein the UE is configured to:

search for a selected component carrier'"'"'s (CC'"'"'s) downlink control information (DCI) in the search space S_k^(L) by identifying a starting control channel elements (CCE) location based on a selected CC'"'"'s carrier index and the aggregation level L until a validly decoded PDCCH candidate is decoded; and

to obtain the selected CC'"'"'s DCI from the validly decoded PDCCH candidate.

17. The communication system of claim 13, wherein a PDCCH candidate includes a cyclic redundancy check (CRC) which is masked by a Cell-Radio Network Temporary Identifier (C-RNTI).

18. The communication system of claim 13, wherein the DCI format includes the CIF.

19. A product including a non-transitory storage medium having stored thereon instructions that, when executed by a machine, result in:

monitoring by an user equipment (UE) operating in a cell and configured with a carrier information field (CIF), a set of PDCCH candidates defined in a search space S_k^(L) at an aggregation level Lε

{1,2,4,8} for a subframe (k) which includes a set of control channel elements (CCEs) and to decode a PDCCH of the set of PDCCH candidates according to downlink control information (DCI).

20. The product of claim 19, wherein the search space S_k^(L) is defined by S_k^(L)=L·

{(Y_k+m)mod └

N_CCE,k/L┘

}+i wherein N_CCE,k is the total number of CCEs in a k^th subframe (kε

{0,1,2,3,4,5,6,7,8,9}), i=0, . . . , L−

1 is a constant, m=0, . . . , M^(L)−

1, and M^(L) is the number of PDCCH candidates to monitor in a given search space.

21. The product of claim 20, wherein Y_k is defined by Y_k=(A·

Y_k-1)mod D wherein, Y_k-1=n_RNTI≠

0, n_RNTI is a Radio Network Temporary Identifier (RNTI) number assigned to the UE, A=39827, D=65537, k=└

n_s/2┘

, and n_s (nε

{0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19}) is the slot number within a radio frame.

22. The product of claim 19, wherein monitoring comprising:

searching for a selected component carrier'"'"'s (CC'"'"'s) downlink control information (DCI) in the search space S_k^(L) by identifying a starting control channel elements (CCE) location based on a selected CC'"'"'s carrier index and the aggregation level L until a validly decoded PDCCH candidate is decoded; and

obtaining the selected CC'"'"'s DCI from the validly decoded PDCCH candidate.

23. The product of claim 19, wherein a PDCCH candidate includes a cyclic redundancy check (CRC) which is masked by a Cell-Radio Network Temporary Identifier (C-RNTI).

24. The product of claim 19, wherein the DCI format includes the CIF.