Abstract: A baseband signal phase-compensation technique offsets undesirable phase shifts, or changes in phase shift, introduced in a transmit signal when changing transmit amplifier operating modes. Such mode changes may, for example, entail switching amplifier stages in and out of an amplification signal path. A phase compensator selectively operates on the baseband signal or signals to subtract out an amount of phase shift equal to the amount of phase shift added by switching one or more additional amplifier stages into the amplification signal path. Compensating baseband signals is this manner may be particularly valuable for the reverse link signal of a mobile terminal operating in a wireless communication environment such as CDMA2000. In such environments, abrupt phase shift changes in the transmit signal associated with transmit signal power control are undesirable.

Abstract: A receiver in a communications system is operated by receiving a radio communications signal transmitted by a station of the communications system and generating a correlation output representing a correlation of the received radio communications signal and a subsequence of a modulation sequence that is selected based on a correlation between the selected subsequence and the modulation sequence. The receiver is then synchronized based on the generated correlation output. The selected subsequence preferably has an optimal out-of-phase correlation with the modulation sequence. According to an aspect of the present invention, the selected subsequence has a minimum out of phase correlation with the modulation sequence in comparison to other subsequences of the modulation sequence. For example, the selected subsequence may have a “minimum maximum” out-of-phase correlation value, a “minimum aggregate” out-of-phase correlation metric, or a combination thereof.

Abstract: A CDMA communication system uses a set of quasi-orthogonal codes to supplement the standard set of Walsh codes used in conventional systems. Users are assigned a code selected from the set of Walsh codes, if available. If the number of users exceeds the number of available Walsh codes, selected users are assigned to quasi-orthogonal codes. The users assigned quasi-orthogonal codes are chosen based on user mobility.

Abstract: A flexible sliding correlator for use in a spread spectrum receiver divides baseband signal samples into different groups, associates each group with a different section of a spreading code, and combines ones of the signal samples with corresponding values in the spreading code section. The groupings and spreading code sections can be changed during operation of the receiver to maximize performance of the receiver under different or changing conditions. In addition, the sample and spreading code value combinations can be further combined in different ways, and the further combinations can be changed during operation of the receiver. According to another aspect of the invention, the baseband signal can be sampled either uniformly or non-uniformly. The phase and frequency of the baseband sampling can be adjusted during operation of the receiver so that samples are taken very close to the optimum sampling position, at the peak of a chip waveform in the baseband signal.

Abstract: A flexible sliding correlator for use in a spread spectrum receiver divides baseband signal samples into different groups, associates each group with a different section of a spreading code, and combines ones of the signal samples with corresponding values in the spreading code section. The groupings and spreading code sections can be changed during operation of the receiver to maximize performance of the receiver under different or changing conditions. In addition, the sample and spreading code value combinations can be further combined in different ways, and the further combinations can be changed during operation of the receiver. According to another aspect of the invention, the baseband signal can be sampled either uniformly or non-uniformly. The phase and frequency of the baseband sampling can be adjusted during operation of the receiver so that samples are taken very close to the optimum sampling position, at the peak of a chip waveform in the baseband signal.

Abstract: A system and method for a synchronizing acquisition of a transmitted signal with a local code in a code modulated communication system. The local code is comprised of a replica of the transmitted code. Samples of the transmitted code are correlated with the local code and resulting periodic output samples having indexes are compared with a threshold. Selected indexes of the samples exceeding the threshold are stored and verified for synchronization. Stored correlation indexes which exceed the threshold are combined, and a responder achieves synchronization between transmitted signal and the local code.