Searching for control channels in a wireless network
A user equipment (UE) may receive an OFDM signal having control channel elements (CCEs). The CCEs may be arranged in levels where a first level aggregates less CCEs than a second level. A processor may search for a control channel from control channel candidates that is comprised of the CCEs. A limited number of CCEs may be searched on the first level.
1. A method of operating a base station the method comprising:
allocating control channel information to a user equipment (UE), the control channel information including control channels represented by nodes of a tree structure, the control channels decodable by the UE using an identifier, the tree structure having three or more levels, the nodes of the tree structure at a highest level of the tree structure comprising a single control channel element and nodes of the tree structure at lower levels of the tree structure comprising a plurality of consecutive control channel elements, wherein allocations of control channels at the highest level of the tree structure are limited and allocations of control channels increase more the lower the level of the three or more levels of the tree structure; and
transmitting the control channel information to the UE.
2. The method of claim 1 , wherein the transmitted control channel information enables the UE to search for a control channel at a lower level of the tree structure prior to searching for a control channel at the highest level of the tree structure.
3. The method of claim 1 , wherein the transmitted control channel information enables the UE to search for a control channel at the highest level of the tree structure prior to searching for a control channel at a lower level of the tree structure.
4. The method of claim 1 , wherein the identifier is a cell radio network temporary identifier (C-RNTI) associated with the UE.
5. The method of claim 1 , wherein the transmitted control channel information enables the UE to determine a Signal to Interference and Noise Ratio (SINR), and to determine, based at least in part on the SINR, which to perform first of the searching for a control channel at a lower level of the tree structure and the searching for a control channel at the highest level of the tree structure.
6. The method of claim 1 , wherein the limited allocation of a highest level control channel and the increased allocation of lower level control channels enables reduced power consumption of the UE.
7. The method of claim 1 , wherein the base station is a base station in a Long Term Evolution (LTE) cellular network.
8. A base station comprising:
a processor operable to allocate control channel information for a user equipment (UE), the control channel information including control channels represented by nodes of a tree structure, the control channels decodable by the UE using an identifier, the tree structure having three or more levels, the nodes of the tree structure at a highest level of the tree structure comprising a single control channel element and nodes of the tree structure at lower levels of the tree structure comprising a plurality of consecutive control channel elements, wherein allocations of control channels at the highest level of the tree structure are limited and allocations of control channels increase more the lower the level of the three or more levels of the tree structure; and
a transmitter operable to transmit the control channel information to the UE.
9. The base station of claim 8 , wherein the transmitted control channel information enables the UE to search for a control channel at a lower level of the tree structure prior to searching for a control channel at the highest level of the tree structure.
10. The base station of claim 8 , wherein the transmitted control channel information enables the UE to search for a control channel at the highest level of the tree structure prior to searching for a control channel at a lower level of the tree structure.
11. The base station of claim 8 , wherein the identifier is a cell radio network temporary identifier (C-RNTI) associated with the UE.
12. The base station of claim 8 , wherein the transmitted control channel information enables the UE to determine a Signal to Interference and Noise Ratio (SINR), and to determine, based at least in part on the SINR, whether to search for a control channel at a lower level of the tree structure or to search for a control channel at the highest level of the tree structure first.
13. The base station of claim 9 , wherein the limited allocation of a highest level control channel and the increased allocation of lower level control channels enables reduced power consumption of the UE.
14. The base station of claim 9 , wherein the base station is a base station in a Long Term Evolution (LTE) cellular network.
15. A user equipment (UE) comprising:
a receiver operable to receive control channel information; and
circuitry operable to search for a control channel in the control channel information by decoding control channels represented by nodes of a tree structure using an identifier, the tree structure having three or more levels, the nodes of the tree structure at a highest level of the tree structure comprising a single control channel element and nodes of the tree structure at lower levels of the tree structure comprising a plurality of consecutive control channel elements, wherein control channel allocations at the highest level of the tree structure are limited and control channel allocations increase more the lower the level of the three or more levels of the tree structure.
16. The UE of claim 15 , wherein searching for a control channel at a lower level of the tree structure is performed prior to searching for a control channel at the highest level of the tree structure.
17. The UE of claim 15 , wherein searching for a control channel at the highest level of the tree structure is performed prior to searching for a control channel at a lower level of the tree structure.
18. The UE of claim 15 , wherein the identifier is a cell radio network temporary identifier (C-RNTI) associated with the UE.
19. The UE of claim 15 , further comprising:
circuitry operable to determine a Signal Interference and Noise Ratio (SINR) of received signals; and
circuitry operable to determine, based at least in part on the SINR, which to perform first of the searching for a control channel at a lower level of the tree structure and the searching for a control channel at the highest level of the tree structure.