Telefonaktiebolaget Lm Ericsson (publ)

Ericsson Gmbh

Interdigital Technology Corporation

Optis Cellular Technology, LLC

Liberato Technologies, Inc.

Kambiz Casey Zangi

Dennis Hui

Leonid Krasny

Jung-Fu Cheng

Rajaram Ramesh

Janet A Stern-Berkowitz

Jiann-Ching Guey

Stephen J Grant

Karl James Molnar

Jonas B Karlsson

Ana Lucia Iacono

Paul Wilkinson Dent

Abdulrauf Hafeez

Bengt Lindoff

Sven Oscar Petersson

Gregory Edward Bottomley

Kumar Balachandran

Ali S Khayrallah

Shing-Wa Wong

Robert Baldemair

Stefan Parkvall

Erik Bengt Dahlman

Henrik Sahlin

Lars Lindbom

Sandeep Chennakeshu

Michael James Lynch

Jonas Medbo

Kevin Peter Johnson

Ulf Axel Lindgren

Carl Wang

Timothy A Axness

Raymond L Toy

Gregg Arthur Charlton

Steven H Isabelle

Ravinder David Koilpillai

Ross L Lintelman

Abdulfauf Hafeez

Rajarem Ramesh

William O Camp

Uif Lindgren

Abduirauf Hafeez

A communication device is described herein that has control (or at least partial control) over which virtual antenna(s) in one or more base stations to use for transmissions. In one embodiment, the mobile phone performs the following steps: (1) receives an antenna subset list (from the scheduling unit) which identifies a configuration of virtual antennas that is associated with the base station(s); (2) uses the antenna subset list to select which virtual antenna(s) in the configuration of virtual antennas to use for transmissions; and (3) sends an antenna selection signal (to the scheduling unit) which contains information that instructs/requests the base station(s)/scheduling unit to use the selected virtual antenna(s) for transmissions.

Signaling support for antenna selection using subset lists and subset masks

A User Equipment in a wireless communication network includes a multiplicity of antennas, from which a subset of antennas is selected using a selection scheme synchronized to the network. A set of sub-carriers is selected from a plurality of sub-carriers using a selection scheme synchronized to the network. The UE receives a plurality of known reference symbols over the selected set of sub-carriers and through the selected subset of antennas. A frequency response for each selected sub-carrier is estimated over only the selected subset of antennas. The results are quantized and transmitted to the network on an uplink control channel.

Efficient uplink transmission of channel state information

Radio transmission in an Orthogonal Frequency Division Multiplex, OFDM, based cellular wireless radio transmission system, wherein radio access equipment of the system connects to multiple geographically spread radio antennas of a Distributed Antenna System, DAS, for transmitting to and receiving radio signals from user equipment. Transmit timings for radio transmission between the user equipment and the antennas of the DAS are established. The radio transmission is scheduled based on the established transmit timings.

Method of and a radio transmission system and radio access equipment for cellular wireless radio transmission

The amount of multi-antenna signals to be transmitted over the backhaul in a Coordinated MultiPoint (CoMP) system from the central processor (CP) to each base station is reduced. Embodiments of the present invention exploit characteristics of the underlying signal structure, and distribute some baseband processing functionalities&#x2014;such as channel coding and the application of the multi-user precoding&#x2014;from the CP to the remote base stations. Additionally, in some embodiments the non-precoded parts of multi-antenna signals are broadcast from the CP to all base stations in the CoMP system, to further reduce the burden on backhaul communications. In one embodiment, the backhaul network is a Gigabit-capable Passive Optical Network (GPON).

Method of downlink signal transport over backhaul communications through distributed processing

The invention relates to a repeater arrangement for amplifying a communication link between a base station and user equipment, wherein the communication link comprises an uplink and a downlink utilizing frequencies within a coherence bandwidth. The repeater arrangement comprises: a first antenna for communication with the base station; a second antenna for communication with the user equipment; an amplifying device operatively connected to the first antenna and to the second antenna for conveying and amplifying communication signals between the first antenna and the second antenna, the amplifying device comprising a first signal path for the uplink and a second signal path for the downlink, the first and second signal paths having equal electrical length, in order to affect said communication signal identically in both uplink and downlink, providing same phase and amplitude characteristics to said communication signal.

Repeater device

An amount of total overhead allocated by a wireless system for transmitting channel state information by a plurality of mobile stations serviced by the wireless system can be controlled by allocating a reporting interval, reporting size and subset of subcarriers to each of the mobile stations for use by the mobile stations in reporting channel state information on the subcarriers included in the subset allocated to the respective mobile stations. At least one of the reporting interval, reporting size and subset of subcarriers allocated to one or more of the mobile stations is modified as a function of the number of mobile stations reporting channel state information so that the total overhead allocated for transmitting the channel state information on all of the subcarriers remains generally constant regardless of the number of mobile stations reporting channel state information.

Method and apparatus for controlling the total overhead used to transmit channel state information in a wireless network

Accurate downlink channel estimates are calculated based on infrequently transmitted Channel State Information (CSI) feedback data from a UE. A plurality of non-uniformly spaced digital CSI feedback samples, representing the frequency response of a downlink communication channel, is received from the UE. The received CSI feedback samples are demodulated and inverse quantized. A time domain tap delay channel model is generated from the inverse quantized CSI feedback samples. The time domain tap delay channel model may be frequency-transformed to obtain a reconstructed frequency response of the downlink communication channel in the frequency domain. Alternatively, channel delays may be estimated based on prior delays and/or known references signals transmitted on the uplink. Channel estimates between CSI reporting instances may be predicted, such as by a sample & hold or a linear predictor. The delays may be presumed fixed, and Kalman filter coefficients evolved over time.

Channel state information reconstruction from sparse data

A UE in a wireless communication network transmits succinct, direct channel state information to the network, enabling coordinated multipoint calculations such as joint processing, without substantially increasing uplink overhead. The UE receives and processes reference symbols over a set of non-uniformly spaced sub-carriers, selected according to a scheme synchronized to the network. The frequency response for each selected sub-carrier is estimated conventionally, and the results quantized and transmitted to the network on an uplink control channel. The non-uniform sub-carrier selection may be synchronized to the network in a variety of ways.

A communication device is described herein that has control (or at least partial control) over which virtual antenna(s) in one or more base stations to use for transmissions. In one embodiment, the mobile phone performs the following steps: () receives an antenna subset list (from the scheduling unit) which identifies a configuration of virtual antennas that is associated with the base station(s); () uses the antenna subset list to select which virtual antenna(s) in the configuration of virtual antennas to use for transmissions; and () sends an antenna selection signal (to the scheduling unit) which contains information that instructs/requests the base station(s)/scheduling unit to use the selected virtual antenna(s) for transmissions.

The required bitrate for reporting channel state information from a network transceiver to the network is dramatically reduced, while maintaining fidelity of channel estimates, by exploiting prior channel estimates and the time correlation of channel response. For a selected set of sub-carriers, the transceiver estimates channel frequency response from pilot signals. The transceiver also predicts the frequency response for each selected sub-carrier, by multiplying a state vector comprising prior frequency response estimate and a coefficient vector comprising linear predictive coefficients. The predicted frequency response is subtracted from the estimated frequency response, and the prediction error is quantized and transmitted to the network. The network maintains a corresponding state vector and predictive coefficient vector, and also predicts a frequency response for each selected sub-carrier. The received prediction error is inverse quantized and subtracted from the predicted frequency response to yield a frequency response corresponding to that estimated at the transceiver.

Exploiting channel time correlation to reduce channel state information feedback bitrate

A Coordinated MultiPoint (CoMP) cell controller performs network-centric link adaptation for User Equipment (UE) in the CoMP cell. The CoMP cell controller receives at least infrequent channel estimates from a UE in the CoMP cell, from which it estimates downlink channel and thermal noise at the UE. The CoMP cell controller is aware of the desired signal to be received at the UE, and the intra-CoMP cell interference to the UE caused by transmissions to other UEs in the CoMP cell. The CoMP cell receives from the UE reports of inter-CoMP cell interference caused by transmissions by other CoMP cells. Based on the downlink channel quality, the desired signal, the intra-CoMP cell interference, the inter-CoMP cell interference, and the thermal noise, the CoMP cell controller performs link adaptation by selecting modulation and coding schemes, and other transmission parameters, for an upcoming transmission duration (such as a TTI).

Network-centric link adaptation for coordinated multipoint downlink transmission

The present invention provides a method and apparatus for channel estimation when the amplitude of a received signal is hard-limited. A channel estimator computes amplitude estimates for the received signal based on the phase samples of the received signal. The amplitude estimates may comprise the expected values of the amplitude given the phase samples. The channel estimator then computes revised channel estimates based on the amplitude estimates and the phase samples. The process may be performed iteratively to refine the channel estimates during each iteration.

Channel estimation and equalization for hard-limited signals

In a Coordinated Multi-point (CoMP) system, the base station (BS) in each serving cell (or sector) is allowed to use not only its own antennas, but also the antennas of neighboring BSs to transmit to mobile terminals in the serving cell to form a floating CoMP cell. The serving BS in each floating CoMP cell computes tentative linear precoding weights for transmissions from the coordinating BSs in the floating CoMP cell to users in the serving cell of the floating CoMP cell. The serving BS determines the power availability for transmit antennas in the floating CoMP cell that are shared with other floating CoMP cells, and scales the tentative precoding weights based on the power availability of the shared transmit antennas to determine final precoding weights so that the power constraints of the shared transmit antennas will not be violated.

Distributed computation of precoding weights for coordinated multipoint transmission on the downlink

Multipoint wireless communications are coordinated in cells with radiation that is emanated from antennas in an inward direction. In an example embodiment, an apparatus includes a first antenna, a second antenna, a third antenna and a controller. The first antenna emanates radiation from a first location in an inwardly direction for a cell. The second antenna emanates radiation from a second location in an inwardly direction for the cell. The third antenna emanates radiation from a third location in an inwardly direction for the cell. The controller coordinates the emanation of the radiation via the first, second, and third antennas so as to reduce intra-cell interference for remote terminals located within the cell. The coordination may be effected in accordance with one or more coordinated multi-point (transmission/reception) (CoMP) techniques. Different numbers of sub-cells and antennas per cell and different CoMP cell organizations may be implemented.

Coordinated multipoint wireless communication

Growing community of inventors

Durham, NC, United States of America

Kambiz Casey Zangi