Method and transmitter for transmit beamforming in a wireless communication system
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorHåkan BERG
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Abstract
The present invention describes a phased array transmitter and a method for beamforming. The phased array transmitter comprises a plurality of transmitting branches configured for up-converting an IF signal to an RF signal with a desired RF phase shift. Each transmitting branch is configured for phase shifting the IF signal with a first phase shift and the LO signal with a second phase shift such that the combined first and second phase shift is the desired RF phase shift of the transmitting branch.
Claims12
A phased array transmitter comprising:
- a splitter configured to split an IF signal into a plurality of input IF signals;
- a plurality of transmitting branches each configured to up-convert an input IF signal to an RF signal with a desired phase shift wherein each transmitting branch is connected to an antenna element configured to transmit for the RF signal;
- wherein each transmitting branch comprises an IF phase shifter configured to phase shift the input IF signal with an IF phase shift to obtain a phase shifted IF signal, an LO phase shifter configured to phase shift the LO signal with an LO phase shift to obtain a phase shifted LO signal, a mixer configured to mix the phase shifted IF signal with the phased shifted LO signal to obtain the RF signal, wherein the combined IF phase shift and LO phase shift is the desired RF phase shift of each transmitting branch.
A method for beamforming in a phased array transmitter, the method comprising:
- splitting an IF signal into a plurality of input IF signals and feeding each of the plurality of input IF signals to a corresponding transmitting branch;
- phase-shifting and up-converting, for each transmitting branch, the input IF signal to an RF signal with a desired RF phase shift;
- and
- transmitting, for each transmitting branch, the RF signal by feeding the RF signal to an antenna element;
- and
- wherein phase-shifting, for each transmitting branch, comprises phase-shifting the input IF signal with an IF phase shift to obtain a phase shifted IF signal, and phase-shifting the LO signal with an LO phase shift to obtain a phase shifted LO signal, wherein the choice of the IF phase shift and the LO phase shift is determined such that the combined IF and LO phase shift is the desired RF phase shift of each transmitting branch;
- and
- wherein up-converting, for each transmitting branch, comprises mixing the phase shifted IF signal and the phased shifted LO signal to obtain the RF signal with the desired RF phase shift.
Dependencies are inferred from the claim text.