Method and apparatus for multi-user transmission
View Patent ↗A method of transmitting data signals from at least two transmitting terminals to at least one receiving terminal with a spatial diversity antenna comprises transmitting from the transmitting terminals transformed data signals, being transformed versions of the data signals; receiving on the spatial diversity means received data signals being at least function of at least two of the transformed data signals; subband processing of at least two of the received data signals in the receiving terminal; and determining estimates of the data signals from subband processed received data signals in the receiving terminal.
1. A communication method comprising:
receiving data signals from at least two transmitting terminals at a receiving terminal comprising a spatial diverse receiving device, wherein the received data signals are each a function of respective transformed data signals, the transformed data signals being transformed versions of a data signal received by the at least two transmitting terminals;
subband processing of the received data signals at the receiving terminal; and
determining estimates of a value of the data signals, on a subband by subband basis, from the subband processed received data signals, wherein said determining includes, for at least one received data signal:
selecting from the received data signals a selected data signal;
determining an intermediate estimate of the selected data signal from the subband processed received data signals;
modifying the subband processed received data signals based on the intermediate estimate of the selected data signal; and
determining intermediate estimates of the remaining data signals from the modified subband processed received data signals;
wherein determining the intermediate estimates of the data signals is based at least upon distinct spatial signatures of the received data signals.
2. The method of claim 1 , wherein spectra of the transformed data signals from respective transmitting terminals are at least partly overlapping.
3. The method of claim 1 , wherein the transformed data signals are transmitted substantially simultaneous from separate transmitting terminals.
4. The method of claim 1 , wherein selecting a data signal is based on the receiving power of the data signals.
5. The method of claim 1 , wherein selecting a data signal is based on the interference ratio of the data signals.
6. The method of claim 1 , wherein the subbands, being involved in the subband processing, are grouped into sets, at least one set comprising at least two subbands; and wherein determining the estimates of the data signals in the receiving terminal comprises:
determining relations between the data signals and subband processed received data signals on a set-by-set basis; and
exploiting the relations between the data signals and the subband processed received data signals for determining the data signals.
7. The method of claim 1 , wherein the transformation of the data signals to transformed data signals comprises inverse subband processing.
8. The method of claim 1 , wherein determining estimates of the data signals from subband processed received data signals in the receiving terminal comprises:
determining intermediate estimates of the data signals from the subband processed received data signals in the receiving terminal; and
obtaining the estimates of the data signals by inverse subband processing the intermediate estimates.
9. The method of claim 1 , wherein the transformation of the data signals to transmitted data signals further comprises guard interval introduction.