Method and apparatus for measuring reporting channel state information in a high efficiency, high performance communications system

A method for measuring and reporting channel state information (CSI) in a multiple input/multiple output (MIMO) system, comprising:

• assigning a plurality of sub-channel subsets to a plurality of transmit antennas of at least one transmitter unit, wherein the sub-channels of each of the sub-channel subsets are noncontiguous;
• transmitting a plurality of Orthogonal Frequency Division Multiplexed (OFDM) pilot waveforms from the at least one transmitter unit to at least one receiver unit, wherein each of the plurality of OFDM pilot waveforms is transmitted over a separate one of the plurality of sub-channel subsets;
• receiving, by the at least one receiver unit, the plurality of OFDM pilot waveforms;
• demodulating the received plurality of OFDM pilot waveforms;
• determining the CSI of the sub-channels corresponding to each of the plurality of sub-channel subsets from the demodulated plurality of OFDM pilot waveforms;
• transmitting the determined CSI to the at least one transmitter unit, and
• preconditioning a transmission symbol according to the determined CSI.

A system for measuring and reporting channel state information (CSI) in a multiple input/multiple output communication system, comprising:

• a base station comprising:
• a plurality of transmit antennas;
• a first processor for preconditioning transmission data, for assigning a plurality of pilot symbols to the plurality of transmit antennas, for assigning a plurality of sub-channel subsets to the plurality of transmit antennas, wherein each of the assigned sub-channel subsets comprises sub-channels that are noncontiguous;
• and
• a plurality of modulators, each modulator connected to the first processor and a separate one of the plurality of transmit antennas, for modulating the assigned plurality of pilot symbols onto the respective assigned plurality of sub-channel subsets;
• wherein the plurality of transmit antennas transmits each of the assigned plurality of pilot symbols over the respective assigned sub-channel subsets;
• and
• a receiver unit comprising;
• at least one receive antenna for receiving the plurality of pilot symbols transmitted over the sub-channel subsets;
• at least one demodulator, coupled to the at least one receive antenna, for demodulating the received plurality of pilot symbols;
• and
• a second processor, connected to the at least one demodulator, for determining the CSI from the demodulated plurality of pilot symbols, and for generating a CSI message for transmission to the base station;
• wherein the at least one receive antenna transmits the CSI message;
• wherein at least one of the plurality of transmit antennas receives the CSI message, at least one of the plurality of modulators modulates the received CSI message, and the first processor preconditions the transmission data according to the CSI obtained from the modulated CSI message.

An apparatus for measuring and reporting transmission characteristics of a multiple input/multiple output communication system, comprising:

• means for assigning a first subset of sub-channels of a plurality of sub-channels to a first transmit antenna of a plurality of transmit antennas of a first transmitter unit, wherein the sub-channels of the first subset of sub-channels are noncontiguous;
• means for transmitting, by the first transmit antenna, a first pilot symbol over the sub-channels of the first subset of sub-channels;
• means for receiving, by a first receive antenna of a first receiver unit, the first pilot symbol;
• means for determining, from the received first pilot symbol, the transmission characteristics of the sub-channels of the first subset of sub-channels;
• means for reporting, by the first receiver unit to the first transmitter unit, an information signal that carries the determined transmission characteristics for the sub-channels of the first subset of sub-channels;
• and
• means for optimizing a set of transmission parameters at the first transmitter unit, based on the information signal.