Iwatsu Electric Company Ltd.

Fuji Xerox Co., Ltd.

Atsushi Fujimoto

Masaru Miyamoto

Hiroshi Kume

Naotaka Maruyama

Koichi Ichimura

The wireless communication devices A and B determine the optimal diversity combining weight information that optimizes a diversity reception state at each antenna group A, A, . . . , Athrough two-way training signal transfer between the wireless communication devices A and B. This optimal diversity combining weight information is set to each antenna of each antenna group A, A, . . . , A. Wireless communication units A', B&#x2032; perform spacial mapping of signals from antenna group A, A, . . . , Ausing MIMO technology. Communication area can be enlarged by hierarchization MIMO using the optimal diversity combining weight information.

Multi-antenna wireless communication method and multi-antenna wireless communication device

Wireless communication devices A and B perform wireless communication with the MIMO technology. The wireless communication devices A and B determine the optimal diversity combining information that optimizes a diversity reception state through a two-way training signal transfer. This determination can be made based on reception level information, baseband reception IQ information, correlation information between a diversity-combining received signal and a predetermined information sequence, or the like, which are obtained when the diversity combining information with respect to each antenna is sequentially changed. The optimal diversity combining information can be determined by receiving training frames or symbols (the number of antennas+1) times.

Multi-antenna wireless communication method, multi-antenna wireless communication system, and multi-antenna wireless communication device

A packet transmitting apparatus comprises a wireless LAN base station and wireless terminals connected to the wireless LAN base station through the wireless LAN. From the wireless LAN base station to the respective wireless terminals, data packets are transmitted in a signal form of frame burst packets without an ACK and a series of header information on the respective data packets are transmitted as notification packets in a signal form of multicast packets. Data packets are individually transmitted from each wireless terminal to the wireless LAN base station by unicast using ACK. Each wireless terminal transmits to the wireless LAN base station a retransmission request to retransmit an unreceived data packet among the frame packets notified by corresponding one of the notification packets. The wireless LAN base station retransmits the packet corresponding to the retransmission request to the wireless terminal that transmits the retransmission request by unicast using ACK.

Packet transmission system in wireless LAN

A decision feed back equalizer provides two feedback routines for one symbol-preceding decided data. The signal space is separated into decidable areas and uncertainty areas. Within each of decidable area the distance between any point and the signal point is small. Within each uncertainty area the distance between any point and the signal point is large. If the symbol-preceding equalized signal is in a decidable area, the piece of decided data is fed back, as it is presumed to be correct. If the symbol-preceding equalized signal exists in an uncertainty area, the piece of decided data is not fed back, as it is presumed to be in error. Here the one piece data is selected from all the predicted symbol-preceding decided data so that the instant equalized data is now in the decidable area. This piece of decided data is now fed back.

Decision feedback equalizer

A baseband digital IQ signal modulated by digital information and a spread spectrum IQ code sequence whose auto-correlation side lobe is equal to zero are frame-synthesized with each other to obtain a transmission baseband IQ signal. A modulated radio-frequency wave obtained by modulating a radio-frequency wave is transmitted over a radio transmission line. From a received baseband signal obtained by receiving the modulated radio-frequency wave is separated a received signal of the spread spectrum IQ code sequence and a received signal of the baseband digital-modulated IQ signal. A waveform equalized signal which is obtained by waveform-equalization of the received signal of the baseband digital modulated IQ signal is demodulated by the use of transmission parameters of the radio transmission line derived from a despread spectrum signal obtained by dispreading the spread spectrum IQ code sequence, to obtain a received data signal of the digital information transmitted from the transmitting side.

Radio transmission method and apparatus for digital information

A method of two-way communication in a multiprocessor system in which two-way data communication is effected between a first processor and a second processor via a common memory. The first processor sequentially writes data A, B, C, . . . , F into the common memory, and forms a coupled queue. If the data A, B, C among the data A, B, C, . . . , F in the coupled queue are sequentially read by the second processor, the coupled queue is divided into a first partial queue constituted by the data D, E, F and a second partial queue constituted by the data A, B, C. The second processor is capable of sequentially reading the data D, E, F from the first partial queue, while the first processor is capable of sequentially reading the data A, B, C from the second partial queue. When the second processor sequentially reads the data A, B, C, . . . , F and the first processor then sequentially reads the data A, B, C, . . . , F in the above-described manner, it follows that the data A, B, C . . . , F are transmitted from the first processor to the second processor and are then returned from the second processor to the first processor. Two-way communication is thus established between the first and second processors.

System of two-way communication between processors using a single queue

There is disclosed a noise eliminating device for an angle-modulated wave, in which a carrier amplitude fluctuation of an angle-modulated input wave is detected in a frequency difference detector to obtain a frequency variation signal corresponding to a frequency variation arising at an amplitude limiter from the carrier amplitude fluctuation. Noise caused by the amplitude fluctuation is eliminated from the angle-modulated input wave by subtracting the frequency variation signal from an output signal of the amplitude limiter after or before the frequency difference detector.

Noise eliminating device for angle-modulated wave

A storage star network for providing maximum propagation delay includes a plurality of terminal stations and a toll center for routing data packets among the stations. Each terminal station includes a memory and each data packet has an associated priority.

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Tokyo, Japan

Atsushi Fujimoto