Abstract:
A methods and apparatus may be used in Very High Throughput (VHT) Wireless Local Area Network (WLAN) management actions. Management action frames such as VHT Action frames may be used to implement VHT features in WLANs. Extensions to 802.11 Action frames may be used to support VHT features and provide backward compatibility. VHT Management Actions may be supported with VHT Action frames and VHT extensions to 802.11 Action frames in various categories such as Direct Link Setup (DLS), Public, Spectrum Management and high throughput (HT). An access point (AP) or a wireless transmit/receive unit (WTRU) may indicate VHT capability by way of signaling.
Abstract:
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.
Abstract:
An apparatus and method for transmitting/receiving data in a mobile communication system using multiple antennas are provided. A receiver estimates a fading channel of received data, selects a weight set relative to a maximum data transmission rate from at least one weight set with elements of a plurality of orthogonal weight vectors, and transmits feedback information including the selected weight set and channel-by-channel state information to a transmitter. The transmitter demultiplexes data to be transmitted on a basis of the feedback information into at least one sub-data stream, multiplies each sub-data stream by an associated weight, and transmits the data.
Abstract:
A method for assisting the adaptation of a signal from a first node (100) to a second node (120) is provided. The first node communicates with the second node in a wireless communication system (110) over a radio link (130). The second node is configured to comprise a codebook, which codebook comprises a set of possible information alternatives used for assisting the adaptation of a signal from the first node to the second node. The second node may select an information alternative from a codebook and send it to the first node to assist the first node how to adapt the signal. The first node is arranged to know a number of subsets, each subset comprising a part of possible information alternatives. The method comprises the steps of sending a configuration request to the second node to restrict the selection of information alternatives to one of the subsets; receiving an information alternative from the second node, which is selected among the at least one subsets configured according to the configuration request.
Abstract:
A space-time signal processing system with advantageously reduced complexity. The system may take advantage of multiple transmitter antenna elements and/or multiple receiver antenna elements, or multiple polarizations of a single transmitter antenna element and/or single receiver antenna element. The system is not restricted to wireless contexts and may exploit any channel having multiple inputs or multiple outputs and certain other characteristics. Multi-path effects in a transmission medium cause a multiplicative increase in capacity.
Abstract:
A method for transmitting signals to reduce feedback overhead and a method for transmitting feedback information for the same are described. In transmitting signals through precoding, different codebook subsets are used in an open-loop transmission mode and a closed-loop transmission mode, thereby reducing feedback overhead. In this case, it is assumed that the codebook subsets for the respective transmission modes are optimized according to each transmission mode.
Abstract:
A method for transmitting channel information in a multi-antenna system, the method includes calculating channel quality information (CQI) with respect to each mode, comparing the CQI with respect to each mode to a threshold value with respect to each mode, and transmitting CQI with respect to a mode having higher CQI than the threshold value as channel information. Good performance can be achieved regardless of the number of users or an SNR of users.
Abstract:
There is provided a communication device capable of transmitting a transfer rate request signal while reducing it and reducing the interference and power consumption when the transfer rate request signal is transmitted substantially without lowering the transmission efficiency in the MIMO communication method. In this device, a modulation encoding unit (125) encodes and modulates transmission data transmitted to a communication partner of the MIMO communication method and the transfer rate request signal in the plurality of transmission antennas. A transmission unit (132) and a transmission antenna (134) transmit a signal from the modulation encoding unit (125). A transmission control unit (120) controls transmission of a signal transmitted from the transmission antenna (134) and transmits a transfer rate request signal of one transmission antenna via the transmission antenna (134) according to a comparison result between a difference of the transfer rate request signal in the respective transmission antenna of the communication partner and a predetermined value.
Abstract:
In a radio system performing scheduled transmission to a plurality of receiving stations from a transmitting station having a plurality of antennas, a transmitting station obtains reception quality information estimated from feedback information obtained from the plurality of receiving stations, determines a transmission system whether to perform beamforming, which transmits data of an identical stream by weighting each of the plurality of antennas based on the obtained reception quality information, or to perform MIMO multiplexing, which transmits data of different streams respectively from the plurality of antennas, and transmits information to identify the determined transmission system by adding to a scheduler management channel.
Abstract:
A transmission/reception apparatus and method for reducing the amount of feedback information transmitted from a receiver in a multi-user MIMO system are provided. A transmitter determines a reference Channel Quality Information (CQI) and transmits the reference CQI to the receiver. Upon receipt of the reference CQI, the receiver compares the received reference CQI with a CQI of a stream received from the transmitter, sets a channel, over which the stream is received, to at least one of Activation and Inactivation, according to the comparison result, and transmits the set channel information to the transmitter. As a result, the receiver, even though it receives multiple streams from the transmitter, transmits to the transmitter the at least one of Activation and Inactivation information of the channel separately for each individual stream, thereby contributing to a reduction in the total amount of feedback information.