Method for propagation channel estimation in an NM Multiple-Input-Multiple-Output (MIMO) communication system comprising a transmitter (202) comprising N transmit antennas and a receiver (204) comprising M receive antennas and a MIMO equalizer (206) comprising multiple taps, where N>1 and M>1. The method includes producing (s402) a single tap equalizer (Q) based on a multi-tap equalizer (Q). The method also includes producing (s404) an inverse effective-channel estimate (Q.sub.e) based on Q, The method also includes inverting (s406) Q.sub.e to produce an effective-channel estimate (H.sub.e), The method also includes producing (s408) H.sub.a based on H.sub.ewherein H.sub.a can be used to determine one or more performance metrics.

A transmitter including a transmit section and a frame formatter. The transmit section is to generate a stream of data to be transmitted using a plurality of antennas and separate the stream of data into a plurality of substreams corresponding to respective ones of the plurality of antennas. The frame formatter is to form respective frames of data from the plurality of substreams. Each of the frames of data includes a short preamble including short training symbols, a long preamble including long training symbols, and a signal field indicating a quantity of the plurality of antennas. The transmit section is further to transmit the frames of data using respective ones of the plurality of antennas.

In accordance with an embodiment a beamforming circuit having a radio frequency (RF) front end and a plurality of beamforming delay circuits coupled to the RF front end. Each of the plurality of beamforming delay circuits includes a common delay circuit and a plurality of individual delay circuits coupled to the common delay circuit. Each of the individual delay circuits are configured to be coupled to an antenna element of a beamforming array.

A method for signal processing includes receiving at a given location at least first and second signals transmitted respectively from at least first and second antennas of a wireless transmitter. The at least first and second signals encode identical data using a multi-carrier encoding scheme with a predefined cyclic delay between the transmitted signals. The received first and second signals are processed, using the cyclic delay, in order to derive a measure of a phase delay between the first and second signals. Based on the measure of the phase delay, an angle of departure of the first and second signals from the wireless access point to the given location is estimated.

A method and an apparatus of transmitting a sounding reference signal by a user equipment is provided. A user equipment transmits a first sounding reference signal through a first antenna, and transmits a second sounding reference signal through a second antenna. Resources for transmitting the first sounding reference signal and the second sounding reference signal are partially different.

.[.An equal gain composite beamforming technique which includes the constraint that the power of the signal output by each antenna is the same, and is equal to the total power of the transmit signal divided by the number N of transmit antennas from which the signal is to be transmitted. By reducing output power requirements for each power amplifier, the silicon area of the power amplifiers are reduced by as much as N times (where N is equal to the number of transmit antennas) relative to a non-equal gain composite beamforming technique..]. .Iadd.A method and apparatus are disclosed for a multiple input multiple output (MIMO) transmission technique by a wireless communications device which includes providing that the power applied to each transmit antenna may be equal to the total power of the transmit signal divided by the number N of transmit antennas from which the signal is to be transmitted. The device may produce a weight for each of the N transmit antennas used in MIMO transmission. Also, the device may determine a total transmit power and produce a multi-carrier signal for transmission. The device may weight the multi-carrier signal for each antenna per the produced weight. Further, the device may apply a power to each of the N transmit antennas, for the weighted multicarrier signal, which is equal to the total transmit power divided by N. Each transmit antenna signal may be amplified by an amplifier coupled to that antenna..Iaddend.

The present invention relates to a method and apparatus for feeding back channel state information in a wireless communication system supporting a three-dimensional multiple input multiple output (3D-MIMO) antenna. Specifically, the method comprises the steps of: receiving information on N beams, (where N is a natural number), precoded for specific antennas among a plurality of antennas constituting a 3D-MIMO antenna; selecting, from among the N beams, at least one specific beam for which to generate channel state information, and determining interference on the basis of M beams, (where M is a natural number, MN1), among the remaining beams; and generating channel state information for the specific beam on the basis of the interference according to the M beams.

A communications system having two terminals, each including two antennas, the communications system using spatial multiplexing. One antenna of a first terminal transmits a tracking tone along with a data signal. Two antennas in a second terminal receive the tracking tone. The signals from the two antennas are processed by a feed circuit. The feed circuit includes a variable delay circuit and a combiner that forms, at a first difference output, a linear combination, of a signal from the first antenna and a signal from the second antenna, in which the tracking tone is canceled. The variable delay circuit is actively adjusted to maintain this cancellation.

A transmitter includes first generator to generate pilot source signal by modulating pilot sequence, second generator to generate data source signal with time length longer than that of pilot source signal by modulating data sequence, first cyclic shifter to perform cyclic shift of first shift amount to pilot source signal to generate first pilot signal, second cyclic shifter to performs cyclic shift of second shift amount to data source signal to generate first data signal, third cyclic shifter to perform cyclic shift of third shift amount to pilot source signal to generate second pilot signal, fourth cyclic shifter to perform cyclic shift of fourth shift amount to data source signal to generate second data signal, first transmit antenna to transmit first pilot signal and first data signal, and second transmit antenna to transmit second pilot signal and second data signal.

A gateway for X2 interface communication is disclosed, comprising: an X2 internal interface for communicating with, and coupled to, a first and a second radio access network (RAN); an X2 language processing module for receiving messages from the first RAN according to a first X2 protocol and mapping the received messages to a second X2 protocol for transmission to the second RAN; and an X2 external interface for communicating with, and coupled to, a gateway in a wireless telecommunications core network. The gateway may further comprise a database for storing a plurality of rules for performing mapping at the X2 language processing module, and a state machine for maintaining state of one of the first RAN or the second RAN, and an interpreter for executing executable code received as part of the received messages and altering the state machine based on the executed executable code, and a regular expression pattern matcher for identifying patterns in the received messages that are present in the first X2 protocol but not present in the second X2 protocol.