Abstract: Apparatus for locating a specific point in a received signal of cyclical nature, the apparatus comprising correlating means (16) for correlating the received signal with a code that is potentially present in the received signal, processing means (20,22,18) for multiplying the correlation result with a time-offset, complex-conjugated version of itself and filtering means (24,26,28) for low pass filtering the multiplication result to produce a signal suited to analysis for determination of said point and estimation of the frequency error.

Abstract: A wireless communications receiver for receiving data blocks, the receiver comprising: a reception unit arranged to receive a wireless signal, to recover from the wireless signal a data frame containing packets; and an LDPC decoder arranged to recover a data block by LDPC decoding one of the packets. A wireless communications receiver for receiving data blocks, the receiver comprising: a reception unit arranged to receive a wireless signal, to recover a data frame from the wireless signal and to recover an encoded block from the data frame; and an LDPC decoder arranged to recover a data block by LDPC decoding the encoded block. A wireless communications transmitter for transmitting data blocks, the transmitter comprising: an encoder arranged to create an encoded block by LDPC encoding a data block; and a transmit unit arranged to load the encoded block into a data frame as a, or as part of a, packet and transmit the data frame wirelessly.

Abstract: Apparatus for locating a specific point in a received signal of cyclical nature, the apparatus comprising correlating means (16) for correlating the received signal with a code that is potentially present in the received signal, processing means (20,22,18) for multiplying the correlation result with a time-offset, complex-conjugated version of itself and filtering means (24,26,28) for low pass filtering the multiplication result to produce a signal suited to analysis for determination of said point and estimation of the frequency error.

Abstract: A method for estimating the distance between a transmitter and a receiver, the transmitter being arranged to transmit a signal as a series of bursts, and the carrier frequency of each burst being set according to a predetermined sequence, the method comprising: forming a first series comprising the measured differences between the phases of successive bursts as received at the receiver; forming a second series comprising estimated differences between the phases of successive bursts as received at a supposed time difference between the transmitter and the receiver; and determining the quality of fit between the first series and the second series.

Abstract: A method for estimating the distance between a transmitter and a receiver, the transmitter being arranged to transmit a signal as a series of bursts, and the carrier frequency of each burst being set according to a predetermined sequence, the method comprising: forming a first series comprising the measured differences between the phases of successive bursts as received at the receiver; forming a second series comprising estimated differences between the phases of successive bursts as received at a supposed time difference between the transmitter and the receiver; and determining the quality of fit between the first series and the second series.