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Mimo channel loopback

A sub-channel and channel feedback technology, applied in the field of channel feedback, can solve the problem of too coarse quantization of channel data in the compression algorithm

Inactive Publication Date: 2012-09-12
TELEFON AB LM ERICSSON (PUBL)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, compression algorithms may quantize the channel data too coarsely, or may require excessive processing in the current state of the art

Method used

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Examples

Experimental program
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Embodiment Construction

[0019] The invention described herein provides timely channel feedback for multi-carrier systems such as OFDM-MISO and OFDM-MIMO systems. To this end, the present invention provides an OFDM transceiver that receives a downlink reference value, such as a pilot signal, on a corresponding receive subcarrier of an OFDM signal received from a remote transceiver. The receiving transceiver maps feedback values ​​comprising downlink reference values ​​such as pilot signals or channel estimates derived therefrom to a single transmit subcarrier of the outgoing OFDM signal. The OFDM transceiver then transmits the outgoing OFDM signal to the remote transceiver to provide channel feedback to the remote transceiver. In some embodiments, the received OFDM signal may include downlink pilot signals on more than one received subcarrier. In these embodiments, the transceiver selects one or more received pilot signals or channel estimates derived therefrom as feedback values ​​and maps different...

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Abstract

A method and apparatus for efficiently providing a large volume of channel feedback, e.g., for OFDM MISO and MIMO systems, is described herein. To that end, a mapping unit in an OFDM transceiver maps channel feedback values, e.g., received reference signal values or channel estimates derived therefrom, on a one-to-one basis to individual transmission subchannels. More particularly, the mapping unit maps a feedback value, e.g., the received reference value or a channel estimate derived therefrom, to a single transmission subchannel of an outgoing OFDM signal. For example, the mapping unit may map the feedback value to an input of a frequency transform unit, such as an inverse discrete Fourier transform unit, to map the feedback value to a single transmission subchannel comprising an OFDM transmission subcarrier. The OFDM transceiver transmits the outgoing OFDM signal to the remote transceiver to provide the feedback value to the remote transceiver.

Description

Background technique [0001] The present invention relates generally to providing channel feedback in wireless systems, and more particularly to providing channel feedback in Orthogonal Frequency Division Multiplexing (OFDM) Multiple Input Multiple Output (MIMO) wireless systems. [0002] Wireless communication systems increasingly seek ways to improve signal quality and / or increase data rates. One solution uses multiple antennas at the transmitter for Multiple-Input Single-Output (MISO) operation. Depending on the relative positions of the transmit antennas, multiple transmit antennas may be used in different ways. If the transmit antennas are closely spaced, eg, on the order of a wavelength or less apart, they can be used in an array to form directional beams. On the other hand, if the transmit antennas are more widely spaced, eg on different sites, they can be used to provide non-coherent or coherent macro-diversity. In non-coherent macrodiversity, the transmitter makes n...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L5/00
CPCH04L5/0048H04L5/0053H04L5/0057
Inventor P.W.登特
Owner TELEFON AB LM ERICSSON (PUBL)