Decoding of PCFICH in LTE for power savings and range improvement
地域：
CA
CA Cupertino
摘要
A mobile device (UE) may decode the Physical Control Format Indicator Channel (PCFICH) blindly, which may include obtaining resource elements (REs) that are reserved for the Physical Downlink Control Channel (PDCCH), based on a largest value of a control format indicator (CFI), finding a total number of control channel elements (CCEs) according to the obtained REs, numbering the CCEs, and decoding the PDCCH for the largest value of the CFI over the numbered CCEs. Accordingly, the UE does not need to decode the PCFICH) specifically. In some cases, the UE may indicate to the network that it is a constrained device, and the network may transmit control information using a reserved CFI value in response to the indication that the UE is a constrained device. The UE may then not decode the PCFICH, and decode the PDCCH based on the PDCCH occupying a first four OFDM symbols.
說(shuō)明書(shū)
This application claims benefit of priority of U.S. Provisional Patent Application Ser. No. 62/012,246 titled “Improved Decoding of PCFICH in LTE for Power Saving and Range Improvement”, filed on Jun. 13, 2014, which is hereby incorporated by reference as though fully and completely set forth herein.
The present application relates to wireless communication devices, and more particularly to apparatuses, systems, and methods for providing improved decoding of PCFICH in LTE among wireless communications devices.
Wireless communication systems are rapidly growing in usage. In recent years, wireless devices such as smart phones and tablet computers have become increasingly sophisticated. In addition to supporting telephone calls, many mobile devices now provide access to the internet, email, text messaging, and navigation using the global positioning system (GPS), and are capable of operating sophisticated applications that utilize these functionalities.
In wireless data communications, automatic repeat request (ARQ; also referred to as automatic repeat query), is used as an error-control method for data transmission that uses acknowledgements (messages sent by the receiver indicating that it has correctly received a data frame or packet) and timeouts (specified time periods allowed to elapse before an acknowledgment is received) to achieve reliable data transmissions. If the sender does not receive an acknowledgment before the timeout, it usually re-transmits the frame/packet until the acknowledgment is received, or the number of re-transmissions has exceeded a predefined limit.
權(quán)利要求
The invention claimed is:1. A method for decoding control format information during wireless communications within a wireless network (NW), the method comprising:making a determination whether or not to perform decoding of a Physical Control Format Indicator Channel (PCFICH); and in response to the determination indicating that the decoding of the PCFICH is to be bypassed:(a) obtaining, by a user equipment (UE), resource elements (REs) that are reserved for a Physical Downlink Control Channel (PDCCH), based on a largest value of a control format indicator (CFI), without decoding the PCFICH corresponding to the PDCCH to obtain an actual value of the CFI; (b) finding a total number of control channel elements (CCEs) according to the obtained REs; (c) numbering the CCEs; and (d) decoding the PDCCH for the largest value of the CFI over the numbered CCEs. 2. The method of claim 1 , further comprising:determining a reliability of the decoding based on a cyclic redundancy code check with all possible Radio Network Temporary Identifiers (RNTIs). 3. The method of claim 1 , further comprising:indicating to the NW that the UE is a constrained device; and sending, by the NW, control information using a reserved CFI value corresponding to the UE being indicated as a constrained device, wherein the largest value of the CFI corresponds to the reserved CFI value sent by the NW. 4. The method of claim 3 , wherein the reserved CFI value is a fixed value previously specified to be used by both the wireless communication device and the network. 5. The method of claim 1 , wherein making the determination comprises making the determination based on one or more specified metrics. 6. The method of claim 5 , wherein the one or more specified metrics comprise one or more of the following evaluated at the UE:Signal-To-Interference-Plus-Noise Ratio; Channel Quality Indicator; Reference Signal Received Power; or Reference Signal Strength Indicator. 7. A communication device comprising:one or more antennas configured to facilitate wireless communications of the wireless communication device; and a processor communicatively coupled to the one or more antennas and configured to:establish communications within a wireless network (NW); communicate to the NW through the established communications that the wireless communication device is a constrained device; receive control information from the network, wherein the control information comprises a reserved control format indicator (CFI) value corresponding to the wireless communication device being indicated as the constrained device; obtain resource elements (REs) that are reserved for Physical Downlink Control Channel (PDCCH), based on the reserved CFI; find a total number of control channel elements (CCEs) according to the obtained REs; number the CCEs; and decode the PDCCH for the reserved value of the CFI over the numbered CCEs. 8. The wireless communication device of claim 7 , wherein the processor is configured to decode the PDCCH based on the PDCCH occupying a specified first number of orthogonal frequency division multiplexing (OFDM) symbols. 9. The wireless communication device of claim 7 , wherein the reserved CFI value is a fixed value previously specified to be used by both the wireless communication device and the network. 10. The wireless communication device of claim 7 , wherein the control information is representative of all constrained devices being grouped together. 11. The wireless communication device of claim 7 , wherein the processor is configured to determine a result of the decoded PDCCH according to a cyclic redundancy code check with all possible Radio Network Temporary Identifiers (RNTIs). 12. The wireless communication device of claim 7 , wherein the NW is configured to group multiple constrained devices in a same one or more subframes, where a fixed value of the CFI is used. 13. An apparatus comprising:a memory configured to store information; and a processor communicatively coupled to the memory and configured to use at least a portion of the stored information to cause a wireless communication device to:wirelessly communicate over a wireless network (NW); make a determination whether or not to perform decoding of a PCFICH); and in response to the determination indicating that the decoding of the PCFICH is to be bypassed:obtain resource elements (REs) that are reserved for a Physical Downlink Control Channel (PDCCH), based on a largest value of a control format indicator (CFI) without decoding the PCFICH corresponding to the PDCCH to obtain an actual value of the CFI; find a total number of control channel elements (CCEs) according to the obtained REs; number the CCEs; and decode the PDCCH for the largest value of the CFI over the numbered CCEs. 14. The apparatus of claim 13 , wherein the processor is configured to further cause the wireless communication device to:determine a reliability of the decoded PDCCH according to a cyclic redundancy code (CRC) check performed with all possible Radio Network Temporary Identifiers (RNTIs). 15. The apparatus of claim 14 , wherein the processor is configured to further cause the wireless communication device to:attempt to decode the PDCCH with a smaller, next largest value of the CFI, responsive to the CRC check failing for a current value of the CFI for which decoding of the PDCCH was performed. 16. The apparatus of claim 13 , wherein the processor is configured to further cause the wireless communication device to:indicate to the NW that the wireless communication device is a constrained device; and receive, from the NW, control information that includes a reserved control format indicator value corresponding to the wireless communication device being indicated as the constrained device, wherein the largest value of the CFI corresponds to the reserved CFI value received from the NW. 17. The apparatus of claim 16 , wherein the reserved CFI value is a fixed value previously specified to be used by both the wireless communication device and the network. 18. The apparatus of claim 16 , wherein the control information is representative of all constrained devices being grouped together. 19. The apparatus of claim 16 , wherein the processor is configured to further cause the wireless communication device to make the determination based on one or more specified metrics. 20. The apparatus of claim 19 , wherein the one or more specified metrics comprise one or more of the following:Signal-To-Interference-Plus-Noise Ratio; Channel Quality Indicator; Reference Signal Received Power; or Reference Signal Strength Indicator.
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