A multi-symbol analysis process compensates for inter-symbol interference in communication signals. The multi-symbol analysis process determines a digital value for a symbol represented by a selected symbol period by correlating a digitized sample within the selected symbol period with a sum of weighted signal components. The sum of weighted signal components includes contributions from the selected symbol period and symbols from a number of other symbol periods that occur before and after the selected symbol period. The multi-symbol analysis process allows more extensive digital filtering, which reduces the bandwidth required to achieve the signal to noise ratio necessary to determine correctly a digital symbol represented by an analog signal. As a result, the multi-symbol analysis process can markedly increase the capacity of communications channels, including satellite communication channels. In the course of the multi-symbol analysis process a quality factor is produced that can be related directly to the probability of error in that decision. This provides an efficient means of error correction with a minimum use of additional bandwidth.
A DSL device performs a frame check sequence operation in a digital signal processor (DSP), i.e., layer one of the OSI seven layer model, heretofore performed only in layer two of the OSI seven layer model. Performing the layer two framing and calculating the frame check sequence in the DSP allows the DSP to use the layer two error detection results, and optionally, the mean squared error vector, to more accurately determine whether to update adaptive receiver parameters.
The invention relates to a method for channel equalization in a receiver, in which a signal is received from a communication channel, the signal containing symbols formed of binary information by phase shift keying. In the receiver, channel estimation is performed to estimate the properties of the communication channel, and samples are taken of the received signal at intervals. In the method, a determined number of samples is examined at the time, and a decision step is taken, in which, to find out the transmitted symbols, bit decisions are computed on the basis of said determined number of samples. After each decision step, it is examined, whether said decision step is to be iterated. Upon iteration of said decision step, at least some of the bit decisions of the preceding decision step are used in addition to the samples under examination at the time, for computing the bit decisions.
A low complexity equalizer and its architecture are disclosed. The low complexity equalizer can identify and remove intersymbol interference caused by digital filters, analog filters, communication channel, channel-filtering and matched-channel filtering of the original transmitted signal.
