Abstract: A communication signal including a plurality of bursts that individually include a plurality of data symbols is processed by both interleaving diversity and duplication diversity prior to transmission in order to preserve the content of the signal when the signal is corrupted by interference during transmission of the signal. A received communication signal having a plurality of bursts that individually include a plurality of data symbols which have been processed for transmission by interleaving diversity is processed to recover the content of the signal when the signal is corrupted by interference during transmission of the signal. Upon determining that the received communication signal may have been corrupted by interference during transmission, the received signal is processed by inserting erasure symbols into a deinterleaver prior to deinterleaving of the data symbols. The erasure symbols are necessary for recovering the content of the transmitted interleaved data symbols.

Abstract: A receiver, which is adapted for demodulating signal carriers at variable frequencies to provide received signals at a plurality of different received frequencies, is calibrated to compensate for a frequency-dependent imbalance in the amplitude and/or the quadrature phase of analog in-phase (I) and quadrature (Q) received-signal components that have passed through receiver circuit paths that may cause such imbalance. I-channel and Q-channel Rx-correction coefficients for each of a plurality of different calibration frequencies are estimated and stored in a lookup table.

Abstract: The preambles of narrow band signals and DSSS signals are prepared for compatible detection. The preamble is encoded by encoding a sequence of identical preamble blocks with sequentially corresponding code elements of a preamble encoding sequence. Each of the identical preamble blocks has the same predetermined pattern of code elements. When the signal is a DSSS signal, the preamble is a spread preamble in which each of the blocks has a number of code elements corresponding to a spread-factor multiple of the number of code elements in a block of an unspread preamble for a narrow band signal. The preambles of both types of received signals are detected by processing a metric representing detected coherent energy with a metric representing detected noncoherent energy, after first determining that the detected noncoherent energy is greater than the average energy of the received signal.