Methods and arrangements in a telecommunications system
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorPeter Larsson
Life of this patent
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Abstract
The present invention relates to a method for providing multiple channel estimation in the field of space time coding in a radio communication system. Space time coding includes transmitter diversity, space(-time) multiplexing and other complex use of signal coding in time and space. The inventive solution of the problems is to send pilot signals concurrently instead of consecutively in order to increase bandwith efficiency during a multitude of channel transfer functions in OFDM and doing so, guaranteeing non-interfering channel estimates at low processing cost for both transmitter and receiver side, in relation to prior art. A purpose of the invention is to provide a channel estimation technique, which is very bandwith efficient.
Claims33
A method in a wireless communication system comprising at least one transmitter provided with at least one antenna and at least one receiving unit provided with at least one antenna and wherein training sequences are transmitted from the at least one antenna of the at least one transmitter to the at least one antenna of the at least one mobile unit, characterized in that
- first, prior to the transmission, a training sequence P(k) is Inverse Discrete Fourier Transformed to a sequence p(n);
- second, for each antenna branch the Inverse Discrete Fourier Transformed sequence p(n) is cyclically rotated by a number of predetermined steps being different for each antenna branch;
- third, the cyclically rotated training sequences p(n−n1), p(n−n2) are transmitted concurrently from different antennas to the receiving unit;
- and
- fourth, at the receiving unit, the received sequences being a superposition of transmitted training sequences, each individually affected by the propagation medium, are used to provide channel impulse response estimates for the transmission from respective antenna.
A method in a wireless communication system comprising at least one transmitter provided with at least two antennas and at least one receiving unit provided with at least one antenna and wherein training sequences are transmitted from the at least two antennas of the at least one transmitter to the at least one antenna of the at least one mobile unit, characterized in that
- first, prior to the transmission, a training sequence P(k) is Inverse Discrete Fourier Transformed to a sequence p(n);
- second, for each antenna branch the Inverse Discrete Fourier Transformed sequence p(n) is cyclically rotated by a number of predetermined steps being different for each antenna branch;
- third, the cyclically rotated training sequences p(n−n1), p(n−n2) are transmitted concurrently from different antennas to the receiving unit;
- and
- fourth, at the receiving unit, the received sequences being a superposition of transmitted training sequences, each individually affected by the propagation medium, are used to provide channel impulse response estimates for the transmission from respective antenna.
A wireless communication system comprising at least one transmitter provided with at least two antennas and at least one receiving unit provided with at least one antenna and wherein training sequences are transmitted from the at least two antennas of the at least one transmitter to the at least one antenna of the at least one receiver unit, characterized in that
- first, prior to the transmission, a training sequence P(k) is Inverse Discrete Fourier Transformed to a sequence p(n);
- second, for each antenna branch the Inverse Discrete Fourier Transformed sequence p(n) is cyclically rotated by a number of predetermined steps (n1,n2), being different for each antenna branch;
- third, the cyclically rotated training sequences p(n−n1), p(n−n2) are transmitted concurrently from different antennas to the receiving unit;
- and
- fourth, at the receiving unit, the received sequences being a superposition of transmitter training sequences each individually affected by the propagation medium, are used to provide channel impulse response estimates for the transmission from respective antenna.
An arrangement in a wireless communication system comprising at least one transmitter provided with at least two antennas and at least one receiving unit provided with at least one antenna and wherein
- training sequences are transmitted from the at least two antennas of the at least one transmitter to the at least one antenna of the at least one receiver unit, characterized by
- means for performing, prior to the transmission, an Inverse Discrete Fourier Transformation on a training sequence P(k) to produce a sequence p(n);
- means for performing, for each antenna branch, a cyclic rotation by a predetermined number of steps of the Inverse Discrete Fourier Transformed sequence, said steps being different for each antenna branch;
- means for transmitting concurrently the cyclically rotated training sequences p(n−n1), p(n−n2) from different antennas to the receiving unit;
- and
- means for using, at the receiving unit, the received sequences, being a superposition of transmitted training sequences each individually affected by the propagation medium, to provide channel impulse response estimates for the transmission from respective antenna.
A wireless communication system comprising at least one transmitter provided with at least two antennas and at least one receiving unit provided with at least one antenna and wherein training sequences are transmitted from the at least two antennas of the at least one transmitter to the at least one antenna of the at least one receiver unit, characterized in that
- first, prior to the transmission, a training sequence P(k) is Inverse Fast Fourier Transformed to a sequence p(n);
- second, for each antenna branch the Inverse Fast Fourier Transformed sequence p(n) is cyclically rotated by a number of predetermined steps (n1,n2), being different for each antenna branch;
- third, the cyclically rotated training sequences p(n−n1), p(n−n2) are transmitted concurrently from different antennas to the receiving unit;
- and
- fourth, at the receiving unit, the received sequences s(n−n1), s(n−n2) being a superposition of transmitter training sequences each individually affected by the propagation medium, are used to provide channel impulse response estimates for the transmission from respective antenna.
An arrangement in a wireless communication system comprising at least one transmitter provided with at least two antennas and at least one receiving unit provided with at least one antenna and wherein
- training sequences are transmitted from the at least two antennas of the at least one transmitter to the at least one antenna of the at least one receiver unit, characterized by
- means for performing, prior to the transmission, an Inverse Fast Fourier Transformation on a training sequence P(k) to produce a sequence p(n);
- means for performing, for each antenna branch, a cyclic rotation by a predetermined number of steps of the Inverse Fast Fourier Transformed sequence, said steps being different for each antenna branch;
- means for transmitting concurrently the cyclically rotated training sequences p(n−n1), p(n−n2) from different antennas to the receiving unit;
- and
- means for using, at the receiving unit, the received sequences, being a superposition of transmitted training sequences each individually affected by the propagation medium, to provide channel impulse response estimates for the transmission from respective antenna.
Dependencies are inferred from the claim text.