OFDM pre-equalizing
AssigneeSony Deutschland GmbH
InventorsRalf Böhnke, Seiichi Izumi
Life of this patent
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Abstract
For example in case of an OFDM multicarrier transmission system the transmission characteristics of subcarriers of a multicarrier transmission system using a plurality of antenna elements (3, 3′) can be adjusted. Particularly the power and the phase of the subcarriers can be adapted. To this object the subcarrier frequency channel (2, 2′) characteristics of the multicarrier transmission are detected (11, 11′) at the side of the transmitter (3). The power of each subcarrier is then distributed by a weighting unit (14, 14′). The subcarriers can be further pre-equalized (1, 1′) by dividing the subcarrier signal respectively by the sum of the squared magnitude of the frequency channel characteristics of all subcarrier signals or a frequency characteristic of the selected antenna element (3, 3′).
Claims28
A method for transmitting an orthogonal frequency division multiplex (OFDM) signal via a plurality of antennas in a wireless transmission system, the OFDM signal carried by a plurality of subcarrier frequencies, the method comprising:
- acquiring channel characteristics of one of the plurality of subcarrier frequencies;
- determining, by processing circuitry, a transmission power allocation vector for the one of the plurality of subcarrier frequencies based on the channel characteristics;
- and
- allocating, by the processing circuitry, a power for the one of the plurality of subcarrier frequencies to an associated one of the plurality of antennas based on multiplication with the transmission power allocation vector,
- wherein the acquiring, the determining, and the allocating are performed for each of the plurality of subcarrier frequencies, and
- the power allocated to the one of the plurality of subcarrier frequencies is normalized with a normalized power allocation vector that is determined for the one of the plurality of subcarrier frequencies.
A transmission device for transmitting an orthogonal frequency division multiplex (OFDM) signal via a plurality of antennas in a wireless transmission system, the OFDM signal carried by a plurality of subcarrier frequencies, the device comprising:
- circuitry configured to acquire channel characteristics of one of the plurality of subcarrier frequencies,
- determine a transmission power allocation vector for the one of the plurality of subcarrier frequencies based on the channel characteristics, and
- allocate a power for the one of the plurality of subcarrier frequencies to an associated one of the plurality of antennas based on multiplication with the transmission power allocation vector,
- wherein the circuitry performs the acquiring, the determining, and the allocating for each of the plurality of subcarrier frequencies, and
- the power allocated to each of the plurality of subcarrier frequencies is normalized with a normalized power allocation vector that is determined for the one of the plurality of subcarrier frequencies.
A wireless system for communicating an orthogonal frequency division multiplex (OFDM) signal via a plurality of antennas, the OFDM signal carried by a plurality of subcarrier frequencies, the wireless system comprising:
- transmitter circuitry configured to acquire channel characteristics of one of the plurality of subcarrier frequencies,
- determine a transmission power allocation vector for the one of the plurality of subcarrier frequencies based on the channel characteristics, and
- allocate a power for the one of the plurality of subcarrier frequencies to an associated one of the plurality of antennas based on multiplication with the transmission power allocation vector, wherein transmitting circuitry performs the acquiring, the determining, and the allocating for each of the plurality of subcarrier frequencies;
- and
- receiver circuitry configured to receive the OFDM signal transmitted by the transmitter circuitry,
- wherein the power allocated to each of the plurality of subcarrier frequencies is normalized with a normalized power allocation vector that is determined for the one of the plurality of subcarrier frequencies.
A receiver incorporating circuitry configured to receive at least one OFDM signal carried by a plurality of subcarrier frequencies via plurality of antennas, said receiver forming part of a wireless transmission system for communicating OFDM signal, said wireless transmission system comprising:
- circuitry configured to acquire channel characteristics of one of the plurality of subcarrier frequencies,
- determine a transmission power allocation vector for the one of the plurality of subcarrier frequencies based on the channel characteristics, and
- allocate a power for the one of the plurality of subcarrier frequencies to an associated one of the plurality of antennas based on multiplication with the transmission power allocation vector,
- wherein the circuitry performs the acquiring, the determining, and the allocating for each of the plurality of subcarrier frequencies, and
- the power allocated to each of the plurality of subcarrier frequencies is normalized with a normalized power allocation vector that is determined for the one of the plurality of subcarrier frequencies.
Dependencies are inferred from the claim text.