Method for receiving radio signals in a mobile station and a mobile station
View Patent ↗A method for receiving radio signals in a mobile station, and a mobile station for sending and receiving radio signals are proposed. The method and the mobile station have the aim of correcting predistorted code-spread and phase-modulated radio signals with respect to a phase error. In this context, in the receiver of the mobile station, the phase is determined for the radio signals, in order to carry out a phase demodulation, and the phases are mapped in a preselected phase zone and averaged, in order to formulate therefrom a phase correction factor, by which the code-despread radio signals are multiplied in order to correct the phase error. The method according to the present invention therefore improves the data detection of the received radio signals.
1. A method for receiving in a mobile station radio signals transmitted from a base station to at least one mobile station, the method comprising:
code-despreading the radio signals transmitted from the base station, wherein the radio signals transmitted from the base station have symbols and are code-spread using one code for each mobile station, and are predistorted in accordance with the expected transmission properties regarding each mobile station, and are modulated with regard to their phases;
determining the phases of the radio signals for each of the symbols to phase demodulate the radio signals;
mapping the determined phases onto a phase zone in accordance with a preestablished rule;
forming an average value from a preestablished number of the determined phases;
determining a phase correction factor from the average value; and
multiplying the phase correction factor by the demodulated radio signals in order to correct a phase error before the radio signals are detected;
wherein the phase correction factor is determined using scaling and conjugation of the average value.
2. The method of claim 1 , wherein the radio signals are modulated with respect to their phases and amplitudes.
3. A mobile station for transmitting and receiving radio signals, the mobile station comprising:
a receiver adapted to:
receive code-spread radio signals and transmit code-spread radio signals together with training signals, wherein the radio signals have symbols and have been predistorted in accordance with the expected transmission properties of the radio channels;
code-despread radio signals transmitted to the mobile station;
determine the phases of the radio signals for each of the symbols to phase demodulate the radio signals;
map the determined phases onto a phase zone in accordance with a preestablished rule;
form an average value from the mapped phases;
calculate a phase correction factor from the average value; and
multiply the phase correction factor by the code-despread radio signals in order to correct a phase error before a data detector detects the radio signals;
wherein the receiver calculates the phase correction factor by scaling and conjugating the average value.
4. The mobile station of claim 3 , wherein the mobile station modulates the radio signals with respect to their phases and their amplitudes.