Abstract: Frequency estimation information obtained when a wireless communication device (WCD) is in one wireless communication system, such as frequency error or offset information, may be translated to a corresponding frequency error in another system, thereby allowing the WCD to perform a handover to the other system with reduced initial frequency error. As a result, the acquisition time involved in acquiring a signal in the other system may be significantly reduced.

Abstract: A communications system receiver incorporates a time-averaged DC component subtracter to subtract a time-averaged DC offset component from a received, processed signal. The time-averaged DC offset is selectably calculated from a moving average or a running average. The selection of the time-averaged DC offset can be done depending on whether the receiver operates in a frequency hop mode or not.

Abstract: A biasing algorithm and apparatus for detecting the modulation format of a received signal is provided. In some aspects, the biasing method and apparatus are used in a mobile phone system implementing EDGE technology that transmits and receives both GMSK and 8PSK modulated signals. In some aspects, the biasing method and apparatus estimates the modulation format of bursts (310) of data blocks (305) of a received signal using information gathered and/or results determined during the modulation detection of one or more previous bursts of a data block to bias the modulation detection of a present burst of the same data block. In some aspects, the gathered information during the modulation detection of a previous burst comprises either the signal-to-noise ratio or the noise energy information of the previous burst.

Abstract: A “unified” modulator for multiple modulation schemes (e.g., GMSK and 8PSK) is described. The waveform for each modulation scheme is generated based on a set of one or more pulse shaping functions. The waveforms for all supported modulation schemes may be generated based on a composite set of all the different pulse shaping functions. The unified modulator includes a filter for each pulse shaping function in the composite set. To generate the waveform for a selected modulation scheme, the set of one or more filters for this modulation scheme is enabled and all other filters are disabled. The outputs from all enabled filters are summed to generate a modulator output. When switching between modulation schemes, a smooth transition may be obtained by (1) providing a suitable data pattern for each filter to be enabled or disabled and (2) generating symbols for the new modulation scheme with an appropriate initial phase.

Abstract: A method and apparatus for interleaving bits in a first sequence is disclosed. An exemplary method comprises storing a set of offset values in at least one table, applying in order each of the set of offset values to identify an adjacent bit pair in the first sequence of the bits for a new interleaved sequence of the bits and incrementing each of the set of offset values until an upper limit is reached to further identify additional adjacent bit pairs in the first sequence of the bits for the new interleaved sequence of the bits. The table is significantly shorter, requiring less memory than that used in a conventional interleaver, particularly a GSM interleaver for half rate speech.

Abstract: A system and method for bad frame indication of a speech frame includes estimating a signal-to-noise ratio (SNR) and checking a cyclic redundancy code (CRC) value of the speech frame. When the speech frame fails CRC error detection or the SNR is below a pre-specified value, a bad frame indication (BFI) flag is set. When the speech frame passes CRC error detection and the SNR is above the pre-specified value, a receive signal quality metric of the speech frame is checked against a high threshold and, if need be, a low threshold. The BFI flag and the receive signal quality metric for the previous speech frame is checked when the current receive signal quality metric is between the high and low thresholds. The BFI flag is set according to the value of the SNR, the CRC value, the current and previous receive signal quality metrics, and the previous BFI flag.

Abstract: Frequency estimation information obtained when a wireless communication device (WCD) is in one wireless communication system, such as frequency error or offset information, may be translated to a corresponding frequency error in another system, thereby allowing the WCD to perform a handover to the other system with reduced initial frequency error. As a result, the acquisition time involved in acquiring a signal in the other system may be significantly reduced.