Abstract: In one embodiment, the invention comprises a channel estimation method, comprising determining a FFT window position, and calculating a delay spread. In another embodiment, the step of determining a FFT window position comprises setting an initial position of the FFT window, computing an energy for each tap, time averaging said energy for each tap, comparing an average energy of each tap with a first threshold multiplied by the average energy of all taps, comparing the average energy of each tap with a second threshold multiplied by a maximum average energy in alias components, updating the set of paths if the average energy of the tap is greater than said second threshold multiplied by the maximum average energy in alias components; and refining the FFT window position.

Abstract: A method and apparatus provides for efficient data rate control and power control processes by transmitting a primary and a secondary pilot channel associated with a data channel. The primary and secondary pilot channels are used for decoding the data. A ratio of power levels of the primary and secondary pilot channels is based on at least one of the data rate and payload size of the data channel. The power level of the primary pilot channel is maintained independent of at least one of data rate and payload size of the data channel. The power level of the secondary pilot channel may be adjusted based on at least one of data rate and payload size of the data channel.

Abstract: A D-PSK demodulator utilizes a two-layer coherent approach to estimate the phase shift of adjacent symbols. There is generated a probability set of each received symbol being one of possible constellation values. There is also generated a probability set of each of possible phase difference between two adjacent symbols. This probability set is then converted into soft bit information according to specific mathematical operation.

Abstract: An apparatus, a cognitive radio, a processor, a method, and a machine-readable medium for detecting a presence of a signal in a communication channel are disclosed. An apparatus includes a processor configured to select one or more peak samples of two or more fields of a sampled signal and configured to determine one or more absolute values of the one or more peak samples of the two or more fields. In addition, the processor is configured to superimpose the one or more absolute values of the one or more peak samples of the two or more fields. The processor is further configured to combine the one or more absolute values that fall within a predetermined window to produce a peak value and configured to compare the peak value with a threshold to determine a presence of a signal in the communication channel.