Abstract: Systems and methods comprising: receiving a signal (S) having a first interfering signal component (FISC); generating a replicated SOI (RSOI); and iteratively performing a process to obtain residual errors for FISC. The process involves: modifying an amplitude of RSOI; obtaining a reference signal (RS) by removing RSOI with the modified amplitude from S; analyzing frequency of RS to obtain an estimated carrier frequency and an estimated symbol rate for FISC; generating a remaining signal by removing, from FRS, a signal having the estimated carrier frequency and symbol rate; and determining a residual error of the remaining signal. Parameters for FISC are then set equal to the estimated carrier frequency and symbol rate that are associated with a lowest residual error. The parameters may be further refined in accordance with another process which involves iteratively modifying a symbol rate of FISC. Yet another process may be performed to determine filter parameters.
Type:
Grant
Filed:
January 13, 2023
Date of Patent:
May 28, 2024
Assignee:
L3HARRIS TECHNOLOGIES, INC.
Inventors:
David R. Keller, L. Andrew Gibson, Jr., Alexander Kimani, Lance Lindsay
Abstract: An apparatus and method for cross clock domain interference cancellation is provided to a communication system which includes a transmitter operated in a first clock domain and a receiver operated in a second clock domain. The apparatus comprises a First-In-First-Out (FIFO) circuit and a cancellation signal generator. The FIFO circuit receives a digital transmission signal of the transmitter in the first clock domain, and outputs the digital transmission signal in the second clock domain according to an accumulated timing difference between the first and second clock domains. The cancellation signal generator generates a cancellation signal for canceling an interference signal received by the receiver according to the digital transmission signal outputted by the FIFO circuit. The interference signal is generated in response to the digital transmission signal.
Type:
Grant
Filed:
February 14, 2012
Date of Patent:
October 21, 2014
Assignee:
Realtek Semiconductor Corp.
Inventors:
Liang-Wei Huang, Shieh-Hsing Kuo, Chi-Shun Weng, Chun-Hung Liu
Abstract: Methods and systems for processing signals are provided and may include removing a DC component from a signal envelope comprising a combined signal within a range of allocated FM channels to generate a modified signal envelope. Fluctuation in power in the signal envelope may be detected based on a ratio of a magnitude of the signal envelope and a magnitude of the modified signal envelope. The removing may further include low-pass filtering the signal envelope to generate a low-pass filtered signal envelope. A square values of the low-pass filtered signal envelope may be determined to generate a squared signal envelope. The squared signal envelope may be high-pass filtered to generate a high-pass filtered signal envelope. The fluctuation in power in the signal envelope may be detected based on a ratio of a magnitude of the high-pass filtered signal envelope and a magnitude of the low-pass filtered signal envelope.
Abstract: Techniques are disclosed for processing a received spread spectrum signal containing multiple signals of interest and one or more interfering signals with known spreading codes. An example method begins with the generation of a despread signal vector for each signal of interest, for a given symbol time, using a corresponding group of correlators for each of the signals of interest. The method continues with the calculating of a covariance matrix for the given symbol time, the covariance matrix representing impairment correlations among the correlators from sources other than the signals of interest, as well as from inter-symbol interference in and among the signals of interest. The covariance matrix includes diagonal blocks that each represent impairment correlations among a single one of the groups of correlators; the diagonal blocks are calculated based on first terms that account in a code-specific manner for same-symbol-time interference from each of the interfering signals.
Abstract: Systems, methods, apparatus, devices and computer program products enhance uplink inter-cell interference cancellation with HARQ retransmissions. The decoding of a data packet depends on whether the interfering packet was decoded. Since the interfering packet is itself transmitted using a HARQ process, the transmission by the victim UT can be accomplished to take this situation into account. The latency of the victim UT can be varied based on the need for energy efficient transmission. In accordance with one specific aspect, if the receiver can decode multiple packets simultaneously, high data rates can be achieved using packet pipelining.
Abstract: A set of channelization codes to be monitored is divided into two groups. The first group includes those codes for which an associated symbol modulation and transmit-diversity scheme is known. In the second group are those codes that are characterized by an unknown symbol modulation or unknown transmit-diversity scheme. The quality of the transmission of each code is then evaluated, using a metric. The metric in turn is used to determine whether the code should be used in estimating the covariance matrix by correlating the RAKE data corresponding to the code (i.e., by computing a correlation matrix for the code) or by first subtracting the channel estimates from the channel samples before correlation (i.e., by computing a covariance matrix for the code). An impairment covariance matrix is computed from the covariance matrices and correlation matrices so computed.
Type:
Grant
Filed:
December 22, 2010
Date of Patent:
November 12, 2013
Assignee:
Telefonaktiebolaget LM Ericsson (Publ)
Inventors:
Elias Jonsson, Yoshitaka Murata, Jaroslaw Niewczas, Amit Singh, Kazuyoshi Uesaka
Abstract: A wireless communications device having a complex vector quantization codebook for use in a downlink multi-user MIMO (multiple-input-multiple-output) mobile broadcast system with feedback enables the interference between data simultaneously sent by the base station to a plurality of mobile terminals to be reliably minimized. The codebook contains many subsets of code vectors that are substantially mutually (i.e., pairwise) orthogonal, or almost orthogonal, to each other. With use of such a codebook, a base station can transmit simultaneously to subsets of mobile terminals associated with these subsets of code vectors with minimal interference therebetween.