Wireless communication system with efficient PDCCH processing

• US 9,660,751 B2
• Filed: 02/17/2015
• Issued: 05/23/2017
• Est. Priority Date: 02/17/2015
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: Batra, Sanjay, Kumar, Atul
• Primary Examiner(s): Wei, Siren
• Application Number:
  US14/623,515
• Publication Number:
  US 20160242149A1
• Time in Patent Office: 826 Days
• CPC Class Codes: H04J 13/16 Code allocation
• CPC Class Codes: H04W 72/00 Local resource management

Abstract

A wireless communication system includes a processor that receives a downlink control information (DCI) associated with a transmission channel used for transmitting a RF signal and a control channel element index associated with the DCI. The processor determines a scrambling code based on the control channel element index for the DCI, scrambles the DCI using the scrambling code, generates a scrambled DCI, and modulates the scrambled. DCI to generate a modulated symbol. The processor uses look-up tables to determine a resource element group (REG) based on the control channel element index, map the modulated symbol to the REG, and generate a transmission frame.

Claims

1. A system comprising a processor and a memory coupled to the processor, the processor for generating a transmission frame of a radio-frequency (RF) signal for a wireless communication system, wherein the processor is configured to:

receive downlink control information associated with a transmission channel used for transmitting the RF signal;

receive a control channel element index associated with the downlink control information;

determine a scrambling code based on the control channel element index;

generate a scrambled downlink control information based on the scrambling code;

modulate the scrambled downlink control information for generating a modulated symbol;

determine a resource element group (REG) based on the control channel element index;

map the modulated symbol to the REG for generating the transmission frame;

store a mapping between a plurality of control channel element indices and a corresponding plurality of scrambling codes in a first lookup table, wherein the plurality of scrambling codes form a scrambling sequence, and wherein the processor fetches the scrambling code from the first lookup table based on the control channel element index;

store a mapping between a plurality of interleave indices and a corresponding plurality of sequential indices in a second lookup table; and

store a mapping between the plurality of sequential indices and the corresponding plurality of mapping addresses in a third lookup table, wherein the plurality of interleave indices correspond to a mapping location of a plurality of modulated symbols.

2. The system of claim 1, wherein the transmission frame comprises a plurality of mapping addresses corresponding to a plurality of REGs, and wherein each REG comprises a plurality of resource elements, wherein the plurality of resource elements correspond to at least one of a plurality of subcarriers of the RE signal and a plurality of orthogonal frequency division multiplexing (OFDM) symbols of the RF signal.

3. The system of claim 1, wherein the processor is further configured to:

fetch a sequential index from the second lookup table based on the control channel element index and fin interleave index that corresponds to the mapping location of the modulated symbol,

fetch a mapping address from the third lookup table based on the sequential index, wherein the mapping address corresponds to the REG, and associating the modulated symbol with the mapping address, thereby mapping the modulated symbol to the REG.

4. The system of claim 3, wherein each modulated symbol of the plurality of modulated symbols includes a plurality of in-phase and quadrature-phase (I/Q) symbols.

5. The system of claim 1, wherein the processor is further configured to receive a plurality of downlink control information corresponding to a plurality of transmission channels.

6. The system of claim 5, wherein the processor comprises a multicore processor having a plurality of processor cores.

7. The system of claim 6, wherein each processor core:

receives at least one downlink control information of the plurality of downlink control information,

receives at least one control channel element index of a plurality of control channel element indices corresponding to the at least one downlink control information,

generates at least one modulated symbol corresponding to the at least one downlink control information,

maps the at least one modulated symbol to a corresponding REG, and

generates the transmission frame.

8. A wireless communication system, comprising:

a power controller for generating downlink control information associated with a transmission channel used for transmitting a radio-frequency (RF) signal and a control channel element index associated with the downlink control information;

a processor connected to the power controller for receiving the downlink control information and the control channel element index, determining a scrambling code based on the control channel element index, generating a scrambled downlink control information based on the scrambling code, modulating the scrambled downlink control information to generate a modulated symbol, determining a resource element group (REG) based on the control channel element index, mapping the modulated symbol to the REG, and generating a transmission frame;

a hardware accelerator connected to the processor for receiving the transmission frame, and converting the transmission frame from the frequency domain to the time domain;

an antenna interface controller connected to the hardware accelerator for receiving the time domain transmission frame, and generating an RF digital data therefrom;

a radio-frequency integrated circuit (RFIC) connected to the antenna interface controller for receiving the RF digital data, generating the RF signal based on the RF digital data, and transmitting the RF signal by way of an antenna port; and

a memory including;

a first lookup table having a mapping between a plurality of control channel element indices and a corresponding plurality of scrambling codes, wherein the plurality of scrambling codes form a scrambling sequence, and wherein the processor fetches the scrambling code from the first lookup table based on the control channel element index;

a second lookup table that includes a mapping between a plurality of interleave indices and a corresponding plurality of sequential indices, wherein the plurality of interleave indices correspond to a plurality of mapping locations of the modulated symbols; and

a third lookup table that includes a mapping between the plurality of sequential indices and a corresponding plurality of mapping addresses.

9. The wireless communication system of claim 8, wherein the transmission frame comprises a plurality of addresses corresponding to a plurality of REGs, and wherein each REG comprises a plurality of resource elements, and wherein the plurality of resource elements correspond to at least one of a plurality of subcarriers of the RF signal and a plurality of orthogonal frequency division multiplexing (OFDM) symbols of the RF signal.

10. The wireless communication system of claim 8, wherein the processor:

maps the modulated symbol to the REG by fetching a sequential index from the second lookup table based on the control channel element index and an interleave index that corresponds to the mapping location of the modulated symbol,

fetches a mapping address from the third lookup table based on the sequential index, wherein the mapping address corresponds to the REG, and

associates the modulated symbol with the mapping address, thereby mapping the modulated symbol to the REG.

11. The wireless communication system of claim 10, wherein each modulated symbol includes a plurality of in-phase and quadrature-phase (IN) symbols.

12. The wireless communication system of claim 11, wherein the power controller further generates a plurality of downlink control information corresponding to a plurality of transmission channels.

13. The wireless communication system of claim 12, wherein the processor comprises a multicore processor having a plurality of processor cores, wherein each processor core:

receives at least one downlink control information of the plurality of downlink control information,

receives at least one control channel element index of the plurality of control channel element indices corresponding to the at least one downlink control information,

generates at least one modulated symbol corresponding to the at least one downlink control information,

maps the at least one modulated symbol to a corresponding REG of the plurality of resource element groups, and

generates the transmission frame.

14. A method of generating and transmitting a transmission frame of a radio-frequency (RF) signal by a wireless communication system, wherein the wireless communication system includes a hardware accelerator, the method comprising:

receiving downlink control information associated with a transmission channel used for transmitting the RF signal;

receiving a control channel element index associated with the downlink control information;

fetching a scrambling code based on the control channel element index from a first lookup table;

generating scrambled downlink control information using the scrambling code;

modulating the scrambled downlink control information to generate a modulated symbol;

determining a resource element group (REG) based on the control channel element index;

mapping the modulated symbol to the REG to generate the transmission frame;

transmitting the transmission frame by the hardware accelerator;

storing a mapping between a plurality of control channel element indices and a corresponding plurality of scrambling codes in the first lookup table, wherein the plurality of scrambling codes form a scrambling sequence;

storing a mapping between a plurality of interleave indices and a corresponding plurality of sequential indices in a second lookup table; and

storing a mapping between the plurality of sequential indices and a corresponding plurality of mapping addresses in a third lookup table.

15. The method of claim 14, wherein the transmission frame comprises a plurality of addresses corresponding to a plurality of REGs, wherein each REG comprises a plurality of resource elements, and wherein the plurality of resource elements correspond to at least one of a plurality of subcarriers of the RF signal and a plurality of orthogonal frequency division multiplexing (OFDM) symbols of the RF signal.

16. The method of claim 14, further comprising:

fetching a sequential index from the second lookup table based on the control channel element index and an interleave index that corresponds to a mapping location of the modulated symbol;

fetching a mapping address from the third lookup table based on the sequential index, wherein the mapping address corresponds to the REG; and

associating the modulated symbol with the mapping address, thereby mapping the modulated symbol to the REG.