Research in Motion Corporation

Blackberry Corporation

Zoltan Kemenczy

Sean Bartholomew Simmons

Huan Wu

Muhammad Dajani

A receiver and associated method estimates a channel impulse response of the communications signal. A communications signal is received as a burst of transmitted symbols, including a known training sequence. The joint estimation of timing offset and initial channel impulse response is determined based on the cross-correlations of the known transmitted symbols and received communications signal. A constant modulus interference removal iteration is applied to improve the initial channel impulse estimation.

Method and receiver for estimating the channel impulse response using a constant modulus interference removal iteration

A filter for reducing co-channel interference within a communications receiver may include a multi-channel, space-time filter circuit that filters n signal parts that have been split from a communications signal by jointly estimating space-time filter weights and multi-channel impulse responses (CIRs). The filter may further include a multi-channel, matched filter circuit that receives multi-channel signals from the multi-channel, space-time filter circuit and has a filter response that is provided by a channel impulse response estimation from the space-time filter circuit.

Joint space-time optimum filters (JSTOF) for interference cancellation

A system and method for detecting a synchronization (sync) signal in a communication signal are disclosed. A received communication signal is stored in a memory and portions thereof are read from the memory and monitored to detect the sync signal. When a detected sync signal is determined to be invalid, previously read portions of the received communication signal, preferably beginning at a portion of the received signal immediately after a start of the detected sync signal, are again read and monitored to detect the sync signal. Such reading and monitoring of previously read portions of a received signal provide for recovery from so-called false triggering based on invalid sync signals.

System and method for synchronization signal detection and recovery from false triggers

A joint demodulation filter for reducing co-channel interference between a desired signal and a co-channel interfering signal may include an input receiving samples of the desired signal and the co-channel interfering signal, a Viterbi decoder, and a first signal path between the input and the Viterbi decoder comprising a first filter. The joint demodulation filter may further include a second signal path between the input and the Viterbi decoder and comprising a linear finite impulse response (FIR) modeler for generating a channel impulse response estimate for the co-channel interfering signal. Additionally, a third signal path may be between the input and the Viterbi decoder and include a whitened matched filter for generating a channel impulse response estimate for the desired signal.

Joint demodulation filter for co-channel interference reduction and related methods

A wireless communications device may include a housing and a wireless transmitter and a wireless receiver carried by the housing. The wireless receiver may include a joint demodulation filter for reducing co-channel interference between a desired signal and a co-channel interfering signal which may include an input receiving samples of the desired signal and the co-channel interfering signal, a Viterbi decoder, and a first signal path between the input and the Viterbi decoder comprising a first filter. The joint demodulation filter may further include a second signal path between the input and the Viterbi decoder and comprising a linear finite impulse response (FIR) modeler for generating a channel impulse response estimate for the co-channel interfering signal. Additionally, a third signal path may be between the input and the Viterbi decoder and include a whitened matched filter for generating a channel impulse response estimate for the desired signal.

Wireless communications device including a joint demodulation filter for co-channel interference reduction and related methods

One illustrative method of scanning a radio frequency (RF) band (e.g. 850 MHz band) for valid RF carrier signals of a wireless communication network (e.g. a GSM network) includes the steps of monitoring an RF channel to receive a candidate RF carrier signal; identifying whether the candidate RF carrier signal is a valid RF carrier signal of the wireless communication network by estimating a bandwidth of the candidate RF carrier signal and, if the estimated bandwidth is different from a predetermined bandwidth associated with valid RF carrier signals of the wireless communication network, identifying that the candidate RF signal is not a valid RF carrier signal of the wireless communication network; and repeating the acts of monitoring and identifying for a next RF channel of a plurality of RF channels associated with the wireless communication network. Preferably, the RF bandwidth estimation is performed together with a system signal detection process (e.g. FCCH detection). Advantageously, the time required to scan the RF band is reduced.

Scanning methods and apparatus which utilize a carrier signal bandwidth test

A receiver for a mobile communication system includes a channel equalizer for receiving a burst and generating a soft decision output associated with the burst, a soft decision correction circuit follows the channel equalizer and a decoder receives and decodes a block of bursts. The soft decision correction circuit calculates a correction factor based on the soft decision output for the burst and applies the correction factor to the burst prior to the burst entering the decoder.

Correction circuit for improving performance in a channel decoder

An interference cancelling matched filter (ICMF) may include an antenna for receiving a signal burst including a training sequence therein, and an adaptive space-time filter connected to the antenna and having settable filter coefficients. The ICMF may further include a channel impulse response estimator for estimating a channel impulse response based upon the training sequence, and a signal blocker operatively connected between the channel impulse response estimator and the adaptive space-time filter so that the filter coefficients thereof are set based upon the training sequence.

Interference canceling matched filter (ICMF) and related methods

A wireless communications device may include at least one virtual antenna, and a space-time filter circuit for filtering a communications signal received by the at least one virtual antenna by jointly estimating space-time filter weights and at least one channel impulse response (CIR). The wireless communications device may further include a matched filter circuit downstream from the space-time filter circuit and having a filter response that is provided by a channel impulse response estimation from the space-time filter circuit.

Joint space-time optimum filters (JSTOF) with at least one antenna, at least one channel, and joint filter weight and CIR estimation

A method includes a foreground process and a background process. In the foreground process, an input signal is processed using a first reference signal to generate an output. A first frequency control signal is generated from the output. A frequency of the first reference signal is controlled based on the first frequency control signal. In the background process, a foreground processed signal is received from the foreground process. The foreground processed signal is processed using a second reference signal. A second frequency control signal is generated from the foreground processed signal. A frequency of the second reference signal is controlled based on the second frequency control signal so that the background processing step removes effects of the foreground controlling step.

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Mississauga, Canada

Zoltan Kemenczy