OFDM diversity transmission
AssigneeSony Deutschland GmbH
InventorSeiichi Izumi
Life of this patent
Estimating the term…
Abstract
In an OFDM transmission a transmission diversity technique is used without orthogonal signalling. The phases of the subcarriers received at the different antenna means (2, 3) are compared by different techniques and then the phases of the signals for different antenna means (2, 3) are adjusted (19) for a subsequent transmission over the OFDM interface. The phase (and optionally amplitude) adjustment is calculated in only one (transmitting) side an no orthogonal signalling is required. The number of antenna means (2, 3) can be increased as much as necessary to get a sharper beam. The negative effects of fading and interference can be reduced so that on the same time a down link transmission power can be reduced.
Claims17
Transmission diversity device, having:
- a plurality of antenna elements (2,3),
- a plurality of processing devices respectively connected to one of the antenna elements (2, 3), and
- phase comparison and adjustment means (10, 19) for comparing phases of signals received at the antenna elements (2, 3) and for adjusting the phases of signals transmitted by the antenna elements (2, 3) according to the result of the comparison (10), characterized in that
- the transmission diversity device (1) is designed for a multicarrier transmission (4, 5) and compares the phases of at least one subcarrier of the multicarrier transmission with the phase of at least one subcarrier of at least one other antenna element (2,3) and adjustes (19) it subsequently for a transmission.
Transmission diversity device according to anyone of the preceding claims, characterized in that
- it comprises a subcarrier phase comparison dependent amplitude adjustment function.
Transmission diversity device according to anyone of the preceding claims, characterized in that
- it comprises a function of averaging (12) the phase differences of a plurality of subcarriers respectively received at one antenna element (2, 3).
Transmission diversity device according to anyone of the preceding claims, characterized in that
- it comprises the function of frequency adjusting (11) the phase differences of the subcarriers received respectively at one antenna element (2, 3).
Method for a wireless transmission diversity transmission by means of a plurality of antenna elements (2, 3) and a plurality of processing devices respectively connected to one of the antenna elements (2, 3), comprising the steps of
- phase comparison (10) of phases of a signal received at the antenna elements (2, 3) and adjustment (19) of the phases of signals to be transmitted by the antenna elements (2, 3) according to the result of the comparison (10), characterized by the steps of
- comparing (10) the phase of at least one subcarrier of a multicarrier transmission for each antenna element (2, 3) with the phase of at least one subcarrier of at least one other antenna element and
- adjusting (19) it subsequently for a transmission..
Dependencies are inferred from the claim text.