Nec Communication Systems, Ltd.

Stefan Aust

Tetsuya Ito

Akira Matsumoto

Peter Davis

Peng Shao

Koichi Yoshimura

Toshiyasu Tanaka

Soshi Kuroshima

The solution of the present invention is a precoding that allows an optimal use of multiple-antennas in a MIMO system. The precoding uses codebooks that are optimized for long-range wireless transmissions. A modified Kerdock codebook {w} allows further improvement of the precoding gain. The modified Kerdock codebook {w} contains new codewords wthat have been modified in order to further improve the transmit bit error rate (BER). The modified codebook {w} allows a precoding gain that is between 2-3 dB. The present invention improves the transmit bit error rate (BER) of a wireless system. It allows a longer range in outdoor MIMO systems. Less signal outage is the result which allows that wireless signals can be transmitted over several kilometers.

Wireless communication system

A wireless communication deviceoperates in either a ROD mode or a non-ROD mode. The non-ROD mode sets the state of the device to an active state that the device can perform wireless communication compliant with a first communication scheme with a communication destination device. The ROD mode: sets the state of the device to either the active state or a sleep state that the device can receive an activation instruction signal compliant with a second communication scheme requiring smaller electric power to receive a signal than the first communication scheme and cannot perform wireless communication compliant with the first communication scheme with the communication destination device; sets the state of the device to the sleep state when a predetermined sleep condition is satisfied; and sets the state of the device to the active state when the device receives the activation instruction signal.

Wireless communication device

A wireless communication terminal includes a communication status measurement element for measuring communication status data representing a communication status of the self terminal at the time of wireless communications; a reference data storage element for storing respective pieces of preset reference data representing communication statuses of a terminal which can be measured at respective locations at the time of wireless communications, in association with respective pieces of location data identifying the respective locations, and a location specifying element for comparing the communication status data measured by the communication status measurement element with the respective pieces of reference data stored in the reference data storage element, and based on the comparison result, specifying a location corresponding to the location data associated with a particular piece of reference data as a location of the self terminal.

Wireless communication terminal

A wireless communication device includes a data transmission and reception section that wirelessly transmits a plurality of test packets; a signal sensing section that senses a power of a spatial radio wave signal on a frequency channel that is the same as the plurality of test packets and outputs sample data of the sensed spatial radio wave signal; a calculation processing section that converts the sample data into time series sample data; a collision detection section that calculates a packet collision rate based on the number of packet collisions and the number of the plurality of test packets if there is a packet collision due to interference of the plurality of test packets with another communication; and a control section that adjusts a parameter that the data transmission and reception section uses based on a calculation result of the collision detection section.

Wireless communication device that is capable of improving data transmission efficiency, associated network, and method

An information classification systemincludes: a classified information storing partfor storing classified information having already been classified into a certain group and group specification information for specifying the group, in association with each other; and a confidence calculating partfor calculating confidence having a value depending on a probability that a group which is specified based on unclassified information as a target to be classified and classified information selected as reference information from among the stored classified information and into which the unclassified information should be classified is a true group.

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Tokyo, Japan

Stefan Aust