Nokia Corporation

Zoltan Safar

Kaj Tapio Jansen

Markku Johannes Heikkilä

Juha Heiskala

A semi-single frequency network (SFN) concept is presented. According to the SFN concept, the same data signal is transmitted from multiple base stations to a mobile terminal simultaneously on the same frequency band. Accordingly, the transmitted signals are combined in the radio channel and the mobile terminal experiences the transmitted signals as one signal propagated through a multipath channel. Additionally, each base station transmits a base station specific pilot signal. The mobile terminal carries out a channel estimation procedure for each received pilot signal and combines the channel estimates to obtain information how to equalize the received data signal. Then, the mobile terminal calculates equalization weights from the combined channel estimates and equalizes the received data signal.

Multipoint data transmission

A timing adjustment value is received, and from the received timing adjustment value is determined an integer portion and a fractional portion. In the frequency domain, the determined fractional portion is applied by rotating a signal. Optionally, a phase shift may also be imposed with the rotation. In the time domain, the determined integer portion is applied by one of inserting samples in the rotated signal or removing samples from the rotated signal in an amount corresponding to the determined integer portion. After the signal rotation to apply the fractional portion, the active sub-carriers are mapped, and the transition from frequency domain to time domain occurs by means of an inverse Fourier transform. A cyclic prefix CP may be added after the Fourier transform, separately or functionally combined with the integer portion shift by modifying the size of the CP to impose the determined integer portion. After other conventional processing known in the art, the rotated signal as advanced/delayed by the sample removal/addition is then transmitted.

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Atlanta, GA, United States of America

Zoltan Safar