Kabushiki Kaisha Toshiba

Yue Wang

Justin Coon

Gillian Huang

Stephen Wang

Mohammud Zubeir Bocus

Lingfeng Wang

Cheran Malsri Vithanage

The embodiments relate to a wireless communications apparatus configured to operate as one of a source node, a relay node or a destination node in a network comprising a plurality of source nodes, relay nodes and destination nodes configured to support dual-hop communication using one of said relay nodes to intercede between one of said source nodes and one of said destination nodes, and a method for selecting a relay node. The wireless apparatus is configured to collect channel characteristics between the intended source node and each relay node, and between each relay node and the intended destination node, and select a relay node for relaying a signal emitted by the intended source node by determining a mode of operation for performing the selection on the basis of collected channel characteristics. The wireless communication apparatus is further configured to change the mode of operation to a different one if the channel characteristics change. The mode of operation of performing the relay node selection is one of a first mode and a second mode. In the first mode; the relay node is selected on the basis of said channel characteristics between the intended source node and each relay node and in the second mode; the relay is selected on the basis of said channel characteristics between each relay node and the intended destination node.

Wireless communications apparatus, a method and a communication system for performing relay selection

Channel activity and subsequent access is determined by antenna selection. A sensing period is allocated into slots, dependent on the number of available antennas. For each slot, a distinct set of antennas is used for sensing for channel activity. Results of channel activity measurements for the slots are combined to form a channel activity report.

Radio apparatus and method of operating the same

A system comprising a source node () and a relay node (). The relay node senses a radio spectrum to provide first sensing data indicating the availability of a signal channel at the relay node. The source node senses the radio spectrum to provide second sensing data indicating the availability of the signal channel at the source node. The source node or relay node generates a channel availability parameter based on the first or second sensing data, respectively. The channel availability parameter comprises fewer bits of information than whichever of the first or second sensing data is used to generate the channel availability parameter. The source node determines whether to send message information to the relay node based on a sensing result obtained by combining the channel availability parameter with whichever one of the first and second sensing data is not used to generate the channel availability parameter.

Spectrum sensing with partial information feedback in a cognitive relay network

In an embodiment a wireless relay device comprises a receiver configured to receive signals from at least a first wireless device and a second wireless device, and to extract, from a signal received from the first wireless device, an indication of a path metric for a path from a source node to the first wireless device, and from a signal received from the second wireless device, an indication of a path metric for a path from the source node to the second wireless device; a processor configured to select, using the extracted indications, a path from the source node to the wireless relay device and to determine a path metric for the selected path; a memory configured to store the path metric for the selected path; and a transmitter configured to transmit an indication of the path metric for the selected path to a third wireless device.

Wireless communication methods and apparatus

A method of relaying a signal in a wireless communications network including a plurality of wireless devices is performed by at least one of said wireless devices to relay a signal in a communication path between one of said plurality of wireless devices and another one of said wireless devices, wherein said at least one of said wireless devices includes a power amplifier for amplifying said signal, the method including receiving a signal from said one of said plurality of wireless devices, determining a peak-to-average power ratio of said received signal under a plurality of predetermined relay modes, determining a back-off value associated with said power amplifier, selecting a mode of relaying said signal from said plurality of predetermined relay modes based on said determined peak-to-average power ratio and said determined back-off value, and transmitting said signal to said another one of said plurality of wireless devices using said selected mode.

Wireless communications method and apparatus

A heterogeneous arrangement of encoder and precoder are provided in a multi-hop communications network. The net effect of the encoder and precoder is to present, to a destination node, a quasi-orthogonal space time block coded transmission.

Method and apparatus for coding a signal in a relay network

A method of shaping signals intended for transmission via at least one antenna, each signal having a respective frequency spectrum and being for transmission via a respective antenna, comprises selecting at least one interference-reducing signal, each interference-reducing signal being such as to modify the signal frequency spectrum for the antenna or a respective one of the antennas to include a respective frequency notch at an interference band, and modifying the frequency spectra with the selected interference-reducing signal or signals, wherein the selection is subject to a constraint on at least one characteristic of the spectra as modified

Interference avoidance

A MMSE equaliser taking into account delays in the reception of signals from plural users. Time delays in reception of signals from plural users may be known or can be measured or estimated and can be used to for the basis for the operation of the equaliser. A low computational complexity version of the equaliser and a regularized equalizer with further reduced complexity for asynchronous reception are also disclosed.

MMSE equaliser

Determining a beamforming vector for a multi-antenna transmitter commences by determining an eigen-beamformer vector from the channel matrix and, for a number of iterations commencing with the eigen-beamformer vector, rotating the vector into a reference direction in vector space such that application of the rotated vector would result in peak radiation being directed in said reference direction, sampling a radiation pattern associated with the rotated eigen-beamformer vector with respect to transmission direction, compressing resultant samples to reduce spatial directivity induced by the vector, developing a rotated candidate beamformer on the basis of said compressed samples and returning said rotated candidate beamformer to the orientation of said vector before said rotating and storing said resultant vector as a candidate vector. Then, the candidate vectors are compared for the iterations and one is selected for use which best meets one or more selection criteria.

Wireless communications apparatus

A block of information is processed before transmission thereof in a block transmission based communication. This comprises inserting a cyclic prefix and a cyclic suffix into the block of information before applying a time reversal based prefilter prior to transmission to the data after cyclic prefix and cyclic suffix insertion, the prefilter being configured on the basis of knowledge of the condition of the channel over which communication is to be effected. Then, at the receiver, a removal operation is operable to remove the effect of cyclic prefix and suffix insertion, leaving a circulant shifted version of the original block. This can be decoded using a diagonal matrix containing frequency domain channel coefficients on its diagonal entries after FFT. For systems with more than two transmit antennas, this facilities the use of full rate OSTBC, regardless of whether real or complex signaling is transmitted.

Growing community of inventors

Bristol, United Kingdom

Yue Wang