Nec Communication Systems, Ltd.

Peng Shao

Akira Matsumoto

Yuki Baba

Tetsuya Ito

Peter Davis

Stefan Aust

Ikumi Wada

A communication device includes a wireless communication unit, an in-transmission information generating unit, and a neighboring signal presence information generating unit. The wireless communication unit transmits and receives wireless frames via an antenna. The in-transmission information generating unit generates in-transmission information representing whether or not a wireless frame is being transmitted from the antenna. The neighboring signal presence information generating unit generates neighboring signal presence information representing whether or not a signal of a predetermined level or higher is present on a wireless channel that is the same as a wireless channel of the wireless frame. The collision detection unit determines a transmission end point of the wireless frame transmitted from the wireless communication unit based on the in-transmission information, determines whether or not there is a signal of the predetermined level or higher on the wireless channel through which the wireless frame is transmitted within a period from the determined transmission end point until a first time elapses, based on the neighboring signal presence information, and determines whether or not the transmitted wireless frame collided with another wireless frame, based on the determination made based on the neighboring signal presence information.

Communication device

A wireless communication terminal has: a wireless module part which transmits a radio frame signal; a transmission loss information detection part which detects transmission loss information representing whether or not the radio frame signal transmitted by the wireless module part has reached a transmission destination; a collision information detection part which detects collision information representing an aspect of collision between the radio frame signal transmitted by the wireless module part and another radio frame signal; and a transmission control part which controls a transmission process executed by the wireless module part, on a basis of the transmission loss information and the collision information.

Transmission control of a wireless communication terminal with transmission loss and collision detection

A transmission part transmits a packet by radio. A power detection part performs, at a given cycle, sampling of power of a spatial radio signal in a packet transmission period during which the transmission part transmits the packet. A collision detection part calculates, as an index value, at least one of the average value and the degree of variation of power of the spatial radio signal in the packet transmission period on the basis of sampled data obtained in the sampling by the power detection part. The collision detection part also determines a reference value on the basis of transmission power of the packet. The collision detection part detects whether or not collision of the packet is present by comparing the index value with the reference value.

Collision detection device, communication device, collision detection method, and program

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.

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Tokyo, Japan

Peng Shao