Nippon Telegraph and Telephone Corporation

Takeo Ichikawa

Masato Mizoguchi

Riichi Kudo

Yusuke Asai

Tomoki Murakami

Hirantha Abeysekera

Yasushi Takatori

Munehiro Matsui

Koichi Ishihara

Shoko Shinohara

Yasuhiko Inoue

Yoshifumi Morihiro

Takahiro Asai

Akira Yamada

Akira Kishida

Kentaro Nishimori

Takefumi Hiraguri

Yukihiko Okumura

Hiroyuki Yamamoto

Hidetoshi Kayama

Akiyoshi Inoki

Yasufumi Morioka

Kenichi Kawamura

Tomoyuki Yamada

Tomoaki Kumagai

Hiroto Yasuda

Masahiro Morikura

Hitoshi Takanashi

Daisuke Koizumi

Hirantha Sithira Abeysekera

Provided is a wireless communication system in which, based on a random access scheme, a transmission opportunity (TXOP) acquired by a wireless access point is granted to a wireless station when performing uplink data transmission from the wireless station to the wireless access point and the TXOP acquired by the wireless station is granted to the wireless access point when performing downlink data transmission from the wireless access point to the wireless station, the system includes a scheduling unit for TXOP granting determining one or more wireless stations having a quality of an uplink data transmission lower than a prescribed value as TXOP responders to which the wireless access point grants the TXOP, and determining one or more wireless stations having a quality of a downlink data transmission lower than the prescribed value as TXOP holders which grant the TXOP to the wireless access point.

Wireless communication system and wireless communication method

Interference in preamble signals and pilot signals in cooperative transmission using interference suppressing technology is avoided. A wireless apparatus for transmitting a wireless signal on which directivity control has been performed to stations in a wireless system including at least one wireless apparatus is provided with a known signal generating unit which generates a known signal to be added to the wireless signal, a weighting processing unit which performs weighting on the known signal generated by the known signal generating unit, and a wireless processing unit which transmits the known signal on which the weighting has been performed by the weighting processing unit.

Wireless signal transmitting method and wireless apparatus

An AP and UE, which perform access control using CSMA/CA, perform a step judging an exposed level in transmission of the AP based on a congesting level in transmission, which is caused by a wireless station in defer transmission that is in a neighborhood of the AP; a step judging an exposed level in reception of the UE based on a congesting level in reception, which is caused by a wireless station in defer transmission that is in a neighborhood of the UE; and a step performing control which changes a channel of the AP, when the exposed level in transmission cannot satisfy expected quality of the AP, and performing control which changes a connected AP of the UE, or control which changes to other network, when the exposed level in transmission or in reception cannot satisfy required quality of the UE or the expected quality of the AP.

Wireless communication system and wireless communication control method

A wireless user equipment performing wireless communication in a primary and a secondary frequency bands, a first wireless access point AP performing the wireless communication in the primary frequency band, and a second wireless base transceiver station BTS performing the wireless communication in the secondary frequency band are included. The AP and the BTS are connected to each other through a network. A UD report transfer unit transfers a UD report including information relating to transmission-waiting user data destined for a receiving node. The receiving node includes a transmission opportunity control unit which sets a fixed transmission prohibition time in a channel in the primary frequency band for a wireless communication device in a vicinity, obtains a transmission opportunity, grants the transmission opportunity to the transmitting node, and causes the user data to be transmitted from the transmitting node according to the transferred UD report.

Provided is a wireless communication system which performs downlink data transmission based on a transmission opportunity acquired by a wireless access point (hereinafter referred to as TXOP access) or a transmission opportunity acquired by a wireless station and granted to the wireless access point (hereinafter referred to as RXOP access), when performing the downlink data transmission from the wireless access point to the wireless station based on a random access scheme, in which the wireless access point includes a control unit performing, on a transmission buffer which sequentially stores data frames to be transmitted for each of wireless stations, processing which lowers an order of priority of the data frames which are to be destined for the wireless station A by the TXOP access at the transmission buffer according to a transmission status of the data frames destined for a wireless station A by the RXOP access.

Provided is a wireless environment evaluation method including a stepacquiring a transmission and reception history of wireless signals transmitted and received between the plurality of wireless stations and acquiring or estimating a number of wireless stations in transmission standby, based on the transmission and reception history; a stepcalculating a normal reception rate S in a congesting situation in reception according to the number of wireless stations in transmission standby; a stepacquiring a normal reception rate S' of the wireless signals per a fixed channel use time from the transmission and reception history in the prescribed wireless station; and a stepdetermining a degree of the exposed situation in reception according to a ratio of the normal reception rate S&#x2032; to the normal reception rate S.

Wireless environment evaluation method and wireless communicaton system

A wireless environment information collection system in which the wireless environment information management unit includes a unit which generates and outputs a channel measurement frame which determines the wireless stations performing stopping of communication over the first frequency channel for a fixed time, starting of measuring channel utilization of the first frequency channel, or both the stopping and the starting among the managed wireless stations, and the managed wireless stations include a unit which performs, at a time designated by the channel measurement frame from the wireless environment information management unit, the stopping of the communication over the first frequency channel, the measuring of the channel utilization of the first frequency channel, or both the stopping and the measuring, and which outputs the obtained wireless environment information to the wireless environment information management unit through the wired network or the wireless network.

Wireless environment information collection system and method

A wireless communication apparatus is provided that is capable of performing setting of a wireless LAN access point so that frequency utilization efficiency of an entire wireless communication system that includes wireless LAN access points of different manufacturers and different model numbers is improved. A wireless communication system which performs setting necessary for a wireless LAN access point constituting a wireless communication network to operate includes: an information collection unit which collects setting information set in the wireless LAN access point and wireless environment information in the wireless LAN access point, a parameter calculation unit which obtains a parameter to be set for the wireless LAN access point, which is a collection source, based on the collected setting information and the collected wireless environment information, and a parameter setting unit which transmits the obtained parameter to the wireless LAN access point, which is a collection source, over a network and performs setting of the parameter.

Wireless communication apparatus, wireless communication system, and wireless communication method

Growing community of inventors

Yokosuka, Japan

Takeo Ichikawa