Multi-carrier transmission system
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorTore Andre
Life of this patent
Estimating the term…
Abstract
A method and arrangement are proposed for compensating intersymbol interference (ISI) in a multicarrier transmission system. Compensation is based on the generation of an estimate of the ISI tail and subtracting the estimate from the received signal. This is achieved by determining an estimate of the transmitted symbols at the receiver by filtering with a transfer function that approximates the inverse of the channel transfer function for the carrier frequencies used. Estimated of two consecutively transmitted symbols are used to generate a difference symbol. When a string of zeroes is appended to this difference symbol and passed through a filter, a transient results which is equivalent to that generated by the consecutively transmitted symbols passed over the channel.
Claims24
In a multi-carrier transmission system wherein digital symbols are transmitted over a transmission medium to a receiver, a method of compensating for intersymbol interference at the receiver comprising:
- determining an estimate of each of two consecutive symbols,
- calculating a difference symbol from the estimates of the two consecutive symbols,
- generating a transient signal utilizing said difference symbol,
- subtracting said transient signal from a second of said two consecutive symbols to substantially cancel the inter-symbol interference generated between said two consecutive symbols.
In a multi-carrier transmission system wherein digital symbols are transmitted over a transmission medium to a receiver, a method of compensating for intersymbol interference at the receiver, the method comprising:
- determining an estimate of each of two consecutive symbols by filtering the digital symbols with a transfer function that is essentially equivalent to an inverse of a transmission medium transfer function at least for carrier frequencies utilized,
- generating a transient signal utilizing the estimates of the two consecutive symbols,
- subtracting said transient signal from a second of said two consecutive symbols to substantially cancel the inter-symbol interference generated between said two consecutive symbols.
In a multi-carrier transmission system wherein digital symbols including a cyclic prefix are transmitted over a transmission medium to a receiver, a method of compensating for intersymbol interference at the receiver, the method comprising:
- determining an estimate of each of two consecutive symbols,
- calculating a difference symbol from the estimates of the two consecutive symbols by discarding the cyclic prefix of the estimate of a first of the two consecutive symbols, retaining the cyclic prefix of the estimate of a second of the two consecutive symbols, and discarding an end of said second of the two consecutive symbols, the end being equal in length to the cyclic prefix, to form a modified second symbol,
- subtracting the modified second symbol from the estimate of the first of the two consecutive symbols,
- generating a transient signal utilizing said difference symbol, subtracting said transient signal from the second of said two consecutive symbols to substantially cancel the inter-symbol interference generated between said two consecutive symbols.
An arrangement for compensating for inter-symbol interference in a receiver of a multi-carrier transmission system wherein digital symbols are transmitted over a transmission medium, the arrangement comprising:
- filter means for generating an estimate of each of two consecutive symbols,
- means for generating a transient signal from the estimates of the two consecutive symbols, and means for subtracting said transient signal from the two consecutive symbols.
An arrangement for compensating for inter-symbol interference in a receiver of a multi-carrier transmission system wherein digital symbols are transmitted over a transmission medium, the arrangement comprising:
- means for generating an estimate of each of two consecutive symbols,
- means for calculating a difference between the estimates of said two consecutive symbols,
- means coupled to said difference calculating means for generating said transient signal from said difference symbol, and means for subtracting said transient signal from the two consecutive signals.
Dependencies are inferred from the claim text.