Multiple-input-multiple-output (MIMO) wireless systems are those that have multiple antenna elements at both the transmitter and receiver. They were first investigated by computer simulations in the 1980s. Since that time, interest in MIMO systems has exploded. They are now being used for third-generation cellular systems (W-CDMA) and are discussed for future high-performance modes of the highly successful IEEE 802.11 standard for wireless local area networks. MIMO-related topics also occupy a considerable part of today's academic communications research. The multiple antennas in MIMO systems can be exploited in two different ways. One is the creation of a highly effective antenna diversity system; the other is the use of the multiple antennas for the transmission of several parallel data streams to increase the capacity of the system. This article presented an overview of MIMO systems with antenna selection. The transmitter, the receiver, or both use only the signals from a subset of the available antennas. This allows considerable reductions in the hardware expense.

MIMO systems with antenna selection

The present invention is designed to provide a user terminal, a radio base station and a radio communication method of novel structures that can achieve a good communication environment. A radio base station non-orthogonal-multiplexes downlink signals for a plurality of user terminals over a given radio resource, a user terminal having received the downlink signals for the plurality of user terminals decodes downlink signal for another user terminal, judges whether or not the downlink signal for the other user terminal has been successfully received, based on the decoding result of the downlink signal, reports a judgement result as to whether or not the downlink signal for the other user terminal has been successfully received and a judgement result as to whether or not a downlink signal for the user terminal has been successfully received, to the radio base station, and then the radio base station executes retransmission control of downlink signals based on reports from the user terminal.

User terminal, radio base station and radio communication method

A wireless telecommunication system comprises base stations for communicating with terminal devices. One or more base stations support a power boost operating mode in which a base station's available transmission power is concentrated in a subset of its available transmission resources to provide enhanced transmission powers as compared to transmission powers on these transmission resources when the base station is not operating in the power boost mode. A base station establishes an extent to which one or more base stations in the wireless telecommunications system support the power boost operating mode conveys an indication of this to a terminal device. The terminal device receives the indication and uses the corresponding information to control its acquisition of a base station of the wireless telecommunication system, for example by taking account of which base stations support power boosting and/or when power boosting is supported during a cell attach procedure.

Telecommunications apparatus and methods

In a mobile communication method by which a mobile station (UE) transmits a control signal to a radio base station (eNB) in an uplink by using an uplink dedicated resource, different methods for determining whether or not a synchronization state is established in the uplink, are used depending on whether or not the uplink dedicated resource is set up.

Mobile communication method and radio base station

Methods and systems for transmitting uplink control information and feedback are disclosed for carrier aggregation systems. A user equipment device may be configured to transmit uplink control information and other feedback for several downlink component carriers using one or more uplink component carriers. The user equipment device may be configured to transmit such data using a physical uplink control channel rather than a physical uplink shared channel. The user equipment device may be configured to determine the uplink control information and feedback data that is to be transmitted, the physical uplink control channel resources to be used to transmit the uplink control information and feedback data, and how the uplink control information and feedback data may be transmitted over the physical uplink control channel.

Uplink control data transmission

Systems and methodologies are described that facilitate configuring a sounding reference signal transmission in a wireless communication environment. A UE can employ coordinated multi-point transmission and/or reception such that multiple cells collaborate to transmit data to the UE and/or receive data from the UE. To support the coordinated multi-point transmission and/or reception, the UE can transmit a sounding reference signal that is configured to enable reliable reception of the sounding reference signal by members of a cooperating set. In addition, configuration of the sounding reference signal can be coordinated to enable more efficient transmission and utilization of the sounding reference signal. Configuration of the sounding reference signal can be based upon information exchanged between the multiple cells. Moreover, the multiple cells can coordinate to set and control a transmit power of the sounding reference signal.

Sounding reference signal for coordinated multi-point operation

Techniques for transmitting and receiving data with spatial interference mitigation in a wireless communication network are described. In one design, a cell may receive precoding information from a first user equipment (UE) communicating with the cell and spatial feedback information (SFI) from a second UE not communicating with the cell. The cell may select a precoding matrix based on the precoding information and the SFI. The precoding matrix may steer a transmission toward the first UE and away from the second UE. The cell may send a reference signal based on the precoding matrix, send a resource quality information (RQI) request to the first UE, receive RQI determined by the first UE based on the reference signal, and determine a modulation and coding scheme (MCS) based on the RQI. The cell may then send a data transmission to the first UE with the precoding matrix and in accordance with the MCS.

Spatial interference mitigation schemes for wireless communication

Transmission patterns for pilot symbols transmitted from a mobile station or base station are provided. The pattern allows for improved receipt of the pilot symbols transmitted. In addition, schemes for improving the ability to multiplex pilot symbols without interference and/ or biasing from different mobile stations over the same frequencies and in the same time slots.

Pilot signal transmission for an orthogonal frequency division wireless communication system

Apparatuses and methodologies are described that enhance performance in a wireless communication system using beamforming transmissions. According to one aspect, the channel quality is monitored. Channel quality indicators can be used to select a scheduling technique, such as space division multiplexing (SDM), multiple-input multiple output (MIMO) transmission and opportunistic beamforming for one or more user devices. In addition, the CQI can be used to determine the appropriate beam assignment or to update the beam pattern.

Channel quality reporting for adaptive sectorization

Systems and methodologies are described that facilitates computing a precoding index which correlates to a precoding matrix within a codebook. According to various aspects, systems and/or methods are described that facilitate computing an effective signal-to-noise ratio (SNR). Such systems and/or methods may further facilitate selecting a precoding matrix and a corresponding precoding index. Such systems and/or methods may still further facilitate employing the precoding matrix in a MIMO wireless communication system.

Alexei Gorokhov

Papers

Sounding reference signal for coordinated multi-point operation

Spatial interference mitigation schemes for wireless communication

Pilot signal transmission for an orthogonal frequency division wireless communication system

Channel quality reporting for adaptive sectorization

A method and apparatus for pre-coding for a mimo system