A method for operating a radio transmitter of a radio transceiver in transmitting payload data symbols via a radio channel of a radio communication system to a radio receiver, the method comprising: - forming payload data vectors of a predetermined length, each including a respective fraction of payload data to be transmitted; - including in at least one of the payload data vectors, in addition to the respective fraction of the payload data, a guard section formed by a pilot value embedded between two multiple-repetition sequences of a reference value; - encoding the payload data vectors to generate payload data symbols as encoded coefficient vectors, by determining respective products of the respective payload data vectors and a code matrix of mutually orthogonal code words (m 0, m 1, m 2, m 254) formed by cyclically shifted m-sequences of a cyclic code, using a Parallel Sequence Spread Spectrum coding scheme, wherein the pilot value is encoded as a pilot code using a predetermined channel-estimation code word (m 0) of the cyclic code; - providing a transmitter-reference-clock signal and deriving from it a symbol clock frequency and a transmitter carrier frequency; and - providing the payload data symbols (S 0, S 1, S 2, S 3) for continuous transmission via the radio channel at the symbol clock frequency, wherein the multiple-repetition sequences of the reference value are encoded such that the code words corresponding to the reference value are not used for encoding the respective fraction of payload data to be transmitted with the at least one payload data symbol that encodes the at least one payload data vector, in order to allow the radio receiver to continuously measure the symbol clock frequency and to perform carrier frequency synchronization with the transmitter without requiring an interruption of the reception of the payload data; - using a transmitter carrier signal having the transmitter carrier frequency to continuously transmit the payload data symbols via the radio channel. - forming payload data vectors of a predetermined length, each including a respective fraction of payload data to be transmitted; - including in at least one of the payload data vectors, in addition to the respective fraction of the payload data, a guard section formed by a pilot value embedded between two multiple-repetition sequences of a reference value; - encoding the payload data vectors to generate payload data symbols as encoded coefficient vectors, by determining respective products of the respective payload data vectors and a code matrix of mutually orthogonal code words (m 0, m 1, m 2, m 254) formed by cyclically shifted m-sequences of a cyclic code, using a Parallel Sequence Spread Spectrum coding scheme, wherein the pilot value is encoded as a pilot code using a predetermined channel-estimation code word (m 0) of the cyclic code; - providing a transmitter-reference-clock signal and deriving from it a symbol clock frequency and a transmitter carrier frequency; and - providing the payload data symbols (S 0, S 1, S 2, S 3) for continuous transmission via the radio channel at the symbol clock frequency, wherein the multiple-repetition sequences of the reference value are encoded such that the code words corresponding to the reference value are not used for encoding the respective fraction of payload data to be transmitted with the at least one payload data symbol that encodes the at least one payload data vector, in order to allow the radio receiver to continuously measure the symbol clock frequency and to perform carrier frequency synchronization with the transmitter without requiring an interruption of the reception of the payload data; - using a transmitter carrier signal having the transmitter carrier frequency to continuously transmit the payload data symbols via the radio channel.