Granted Patent B2

US 12,610,364 · App. 18/213,822 · Granted Apr 21, 2026

Inventors: Brian W. Stevens (Elkridge, MD); Katherine M. Woolls (Baltimore, MD); Jacob M. Ray (Marriottsville, MD); Jared S. Everett (Washington, DC); Yongwen Yang (Columbia, MD); Benjamin E. Henty (Columbia, MD); Abdullahi A. Inshaar (Columbia, MD); Avik Dayal (Laurel, MD)

Assignee: The Johns Hopkins University

H04W72/1263H04W72/232

Abstract

Claims (51)

1 . A method of determining control and scheduling information of a network via an out-of-network monitor, the method comprising:

passively receiving a radio frequency (RF) waveform of a radio interface, using only information that can be observed over the radio interface by the out-of-network monitor, having downlink control information (DCI) scrambled via a scrambling identity unknown to the out-of-network monitor, the DCI providing the control and scheduling information;

performing a cell search to determine cell identity information for a cell via which the RF waveform is received;

performing a beam search and beam detection for the cell to estimate a signal quality of the RF waveform;

in response to the signal quality being above a threshold signal quality, decoding scheduling information associated with the RF waveform;

detecting a control channel encoded with an unknown identity based on the scrambling identity and extracting resource elements of the control channel based on the scheduling information;

attempting to decode the control channel via a re-encoding technique that is tested for accuracy and, in response to accuracy testing not passing, via a blind scrambling seed recovery technique;

recovering the DCI based on the re-encoding technique or the blind scrambling seed recovery technique; and

obtaining the control and scheduling information from the DCI.

2 . The method of claim 1 , wherein the re-encoding technique comprises:

attempting to decode encoded bits of common control channel information from the control channel via an assumed identity;

re-encoding the common control channel information using a guessed identity to define re-encoded bits; and

comparing the control channel encoded with the guessed identity to the encoded bits to determine if the re-encoding is successful based on a number of bit errors.

3 . The method of claim 2 , wherein, in response to the number of bit errors being below a threshold bit error, recovering the DCI is performed based on the re-encoding technique without the blind scrambling seed recovery technique.

4 . The method of claim 3 , wherein the re-encoding technique is optimized via Monte Carlo thresholding.

5 . The method of claim 1 , wherein the blind scrambling seed recovery technique is performed in response to a number of bit errors being above a threshold bit error.

6 . The method of claim 5 , wherein the blind scrambling seed recovery technique comprises solving a system of equations to determine a set of unknown information associated with the DCI, the system of equations including a set of known information associated with the DCI, the set of unknown information, and a transformation matrix applied to the set of known information to obtain the set of unknown information to determine the DCI.

7 . The method of claim 6 , wherein the set of known information comprises received bits and a known portion of a length-31 Gold sequence.

8 . The method of claim 6 , wherein the system of equations is solved via a Galois field row reduction.

9 . The method of claim 6 , wherein solving the system of equations determines a calculated DCI payload and a seed value used to determine an unscrambled and decoded result, and

wherein the calculated DCI payload is compared to the unscrambled and decoded result to determine the DCI.

10 . The method of claim 9 , wherein responsive to a success of re-encode technique or scrambling seed technique in which a bit error is lower than a set threshold, DCI bit parsing is employed.

11 . The method of claim 9 , wherein responsive to no match between the calculated DCI payload and the unscrambled and decoded result, log-likelihood ratio (LLR) optimization is employed to determine the DCI.

12 . The method of claim 11 , wherein the LLR optimization comprises:

sorting received bit LLRs in descending order;

down-selecting N rows of the transformation matrix and the set of known information based on greatest magnitude LLRs to define an updated transformation matrix; and

iteratively calculating a rank of the updated transformation matrix until the rank of the updated transformation matrix is equal to N.

13 . An apparatus for determining control and scheduling information of a network from outside the network, the apparatus comprising processing circuitry configured to:

passively receive a radio frequency (RF) waveform of a radio interface, using only information that can be observed over the radio interface by the out-of-network monitor, having downlink control information (DCI) scrambled via a scrambling identity unknown to the apparatus, the DCI providing the control and scheduling information;

perform a cell search to determine cell identity information for a cell via which the RF waveform is received;

perform a beam search and beam detection for the cell to estimate a signal quality of the RF waveform;

in response to the signal quality being above a threshold signal quality, decode scheduling information associated with the RF waveform;

detect a control channel encoded with an unknown identity based on the scrambling identity and extracting resource elements of the control channel based on the scheduling information;

attempt to decode the control channel via a re-encoding technique that is tested for accuracy and, in response to accuracy testing not passing, via a blind scrambling seed recovery technique;

recover the DCI based on the re-encoding technique or the blind scrambling seed recovery technique; and

obtain the control and scheduling information from the DCI.

14 . The apparatus of claim 13 , wherein the re-encoding technique comprises:

attempting to decode encoded bits of common control channel information from the control channel via an assumed identity;

re-encoding the common control channel information using a guessed identity to define re-encoded bits; and

comparing the control channel encoded with the guessed identity to the encoded bits to determine if the re-encoding is successful based on a number of bit errors.

15 . The apparatus of claim 14 , wherein, in response to the number of bit errors being below a threshold bit error, recovering the DCI is performed based on the re-encoding technique without the blind scrambling seed recovery technique.

16 . The apparatus of claim 13 , wherein the blind scrambling seed recovery technique is performed in response to a number of bit errors being above a threshold bit error.

17 . The apparatus of claim 16 , wherein the blind scrambling seed recovery technique comprises solving a system of equations to determine a set of unknown information associated with the DCI, the system of equations including a set of known information associated with the DCI, the set of unknown information, and a transformation matrix applied to the set of known information to obtain the set of unknown information to determine the DCI.

18 . The apparatus of claim 17 , wherein solving the system of equations determines a calculated DCI payload and a seed value used to determine an unscrambled and decoded result, and

wherein the calculated DCI payload is compared to the unscrambled and decoded result to determine the DCI.

19 . The apparatus of claim 18 , wherein responsive to a success of re-encode technique or scrambling seed technique in which a bit error is lower than a set threshold, DCI bit parsing is employed, and

wherein responsive to no match between the calculated DCI payload and the unscrambled and decoded result, log-likelihood ratio (LLR) optimization is employed to determine the DCI.

20 . The apparatus of claim 19 , wherein the LLR optimization comprises:

sorting received bit LLRs in descending order;

down-selecting N rows of the transformation matrix and the set of known information based on greatest magnitude LLRs to define an updated transformation matrix; and

iteratively calculating a rank of the updated transformation matrix until the rank of the updated transformation matrix is equal to N.

Assignments (2)

Continuity (2)

References Cited (29)