Nippon Telegraph and Telephone Corporation

Matsushita Electric Industrial Co., Ltd.

Shigeru Kuwano

Jun Terada

Kenji Miyamoto

Naotaka Shibata

Takehiro Moriya

Yutaka Kamamoto

Takayoshi Tashiro

Takeshi Sakamoto

Masaru Fuse

Satoshi Shigematsu

Nobuyuki Tanaka

Tomoaki Yoshida

Kuniaki Utsumi

Katsumi Iwatsuki

Daisuke Hisano

Mitsuhiro Teshima

Jun-ichi Kani

Kazushige Yonenaga

Yoshikazu Ishii

Seiji Yoshida

Hiroaki Asano

Toru Shiozaki

Noriko Iiyama

Seiji Norimatsu

Nori Shibata

Hitoshi Uematsu

A wireless communication system includes a control device and at least one communication device. The control device includes a scheduler configured to generate control information for a process of a physical layer in wireless communication between the communication device and a terminal, an encoding unit configured to generate encoded data by performing encoding on data to be transmitted to the terminal on the basis of the control information, and a transmission unit configured to transmit the control information to the communication device when the control information is generated and transmits the encoded data to the communication device when the encoded data is generated. The communication device includes a reception unit configured to the control information and the encoded data from the control device; and a signal processing unit configured to perform signal processing for transmitting the encoded data received by the reception unit to the terminal on the basis of the control information received by the reception unit.

Wireless communication system and communication method

An optical communication system includes a signal processing apparatus and a wireless apparatus between which functions of a base station are divided, wherein a periodic symbol sequence including a cyclic prefix appended to a signal of a predetermined size to which an IFFT (Inverse Fast Fourier Transform) has been applied is transmitted between the signal processing apparatus and the wireless apparatus by means of digital RoF (Radio over Fiber) transmission, the signal processing apparatus and the wireless apparatus each include a transmission unit and a reception unit, the transmission unit includes: a compression size determination unit that acquires symbol information relating to a starting position of the symbol sequence and lengths of symbols constituting the symbol sequence, and that determines, based on the acquired symbol information, a compression size for each of symbols that are to be compressed; and a compression unit that compresses the symbol sequence in units of determined compression sizes, and the reception unit includes: an expansion size determination unit that determines an expansion size for each of symbols in the symbol sequence that are to be expanded; and an expansion unit that expands the symbol sequence in units of determined expansion sizes.

Optical communication system and optical communication method

A wireless communication system includes an RF reception unit configured to receive a radio signal from a terminal; a channel estimation unit configured to estimate channel information of a wireless transmission path with respect to the terminal; a demodulation unit configured to perform soft decision demodulation on the radio signal; a quantization unit configured to quantize a log likelihood ratio obtained through soft decision demodulation in the demodulation unit, on the basis of a statistical distribution determined using an average value of the log likelihood ratio determined in accordance with a modulation scheme used in wireless communication with the terminal and a variance of a log likelihood ratio obtained on the basis of the channel information; and a decoding unit configured to perform a decoding process on the log likelihood ratio quantized by the quantization unit.

A relay apparatus includes: an estimation unit selects a code book number corresponding to a reception SNR range based on an estimated reception SNR value; a soft demodulation unit that performs soft demodulation on a received first signal to detect a likelihood of the received first signal; a first memory unit that stores a first quantization code book showing, for each code book number, a relationship between a quantization parameter and a likelihood quantization bit value; a quantization unit that refers the first quantization code book to obtain a relationship between a quantization parameter and a likelihood quantization bit value that corresponds to the selected code book number, and adaptively quantizes the detected likelihood by using the obtained relationship to obtain a likelihood quantization bit value; and a transmission unit that transmits, to the receiving apparatus, a second signal including the obtained likelihood quantization bit value and the selected code book number.

Communication system, relay apparatus, receiving apparatus, relay method, receiving method, relay program, and receiving program

In a partial centralization system configuration, a wireless communication system of the present invention transmits a precoding matrix generated in a media access control (MAC) function or a matrix or vector obtained by dividing the precoding matrix between central unit equipment and distributed unit equipment in addition to data of modulated symbols necessary for a precoding matrix calculation and downlink control information (DCI) corresponding to the data.

Wireless communication system, central unit equipment, distributed unit equipment, communication method of central unit equipment, and communication method of distributed unit equipment

An optical communication system includes a signal processing apparatus and a wireless apparatus between which functions of a base station are divided, wherein a periodic symbol sequence including a cyclic prefix appended to a signal of a predetermined size to which an IFFT (Inverse Fast Fourier Transform) has been applied is transmitted between the signal processing apparatus and the wireless apparatus by means of digital RoF (Radio over Fiber) transmission, the signal processing apparatus and the wireless apparatus each include a transmission unit and a reception unit, the transmission unit includes: a first separation unit that acquires symbol information relating to a starting position of the symbol sequence and lengths of symbols constituting the symbol sequence, and that equalizes the lengths of the symbols by separating a portion of the symbol sequence based on the acquired symbol information; and a compression unit that compresses symbols that are to be compressed from which the separated portion of the symbol sequence has been removed, and the reception unit includes an expansion unit that expands the compressed symbols and restores the symbols.

A station-side device performs transmission and reception of an optical signal to and from a subscriber-side device, and includes a communication control unit configured to perform optical signal communication using a plurality of wavelengths by wavelength division multiplexing and time division multiplexing; and a registration unit configured to set an acceptance period in at least one wavelength among the plurality of wavelengths, to perform a new registration of a subscriber-side device in response to a registration request of the subscriber-side device received within the acceptance period, and not to set the acceptance period in at least one other wavelength among the plurality of wavelengths.

Station-side device and communication method

A wireless communication system includes distributed units communicating with a terminal device and a central unit connected to the distributed units and receiving and processing signals from the distributed units. The central unit includes a host function unit to pre-notify the distributed units if a received signal from the terminal device is a target of coordination between distributed units, hard/soft determination units configured to separate received signals from the distributed units into a hard decision value and a soft decision value based on presence or absence of coordination between the distributed units, transmit the hard decision value to the host function unit as is, and transmit the soft decision value to a signal combining unit, the signal combining unit combines soft decision values output from the hard/soft determination units and outputs a combined soft decision value, and a decoding unit performs decoding using the soft decision value output from the signal combining unit.

Wireless communication system and wireless communication method

A transmission system for relaying communication of communication systems includes a relay unit configured to relay uplink communication and downlink communication of a communication system that performs a time division duplex (TDD) mode through signals of different wavelengths, an information acquisition unit configured to acquire time division information indicating timings of the uplink communication and the downlink communication in the communication system that performs the TDD mode, a calculation unit configured to calculate a free period unused in relaying of communication of the communication system that performs the TDD mode on the basis of the time division information for each wavelength, and an instruction unit configured to instruct the relay unit to relay communication of another communication system different from the communication system that performs the TDD mode in the free period for each wavelength calculated by the calculation unit.

Transmission system and transmission method

A base station apparatus is provided with at least one remote unit apparatus each including at least one antenna, and a central unit apparatus connected to each remote unit apparatus via a transmission path. The antenna provided in the remote unit apparatus receives a transmission signal wirelessly transmitted from at least one wireless terminal each including at least one antenna. The remote unit apparatus includes a channel estimation unit that estimates channel information between the antenna of the wireless terminal and the antenna of the remote unit apparatus, using a reception signal received by the antenna provided in the remote unit apparatus, a likelihood calculation unit that calculates likelihood of each transmission signal included in the reception signal, for each antenna provided in the remote unit apparatus, using the channel information estimated by the channel estimation unit, and an inter-unit transmission unit that transmits likelihood information calculated by the likelihood calculation unit to the central unit apparatus. The central unit apparatus is provided with an inter-unit receiving unit that receives the likelihood information transmitted from the inter-unit transmission unit, and a signal detection unit that combines the likelihood information received by the inter-unit receiving unit, and outputs a signal corresponding to each transmission signal transmitted from the wireless terminal, using combined likelihood information.

Base station apparatus, wireless communication system, and communication method for uplink coordinated multi-point transmission and reception with intra-phy split base station architecture

Since a sampling frequency of RRU is always constant, A/D conversion may be performed with a sampling frequency higher than necessary with respect to a frequency band width of a radio signal. A sampling frequency change function, and the sampling frequency is reduced in a range where a aliasing component does not deteriorate signal quality of a desired signal component when the sampling frequency is decreased, based on radio band allocation information, or signal transmission between BBU and RRU is stopped in a no signal section, whereby a band required for digital RoF transmission between the BBU and the RRU is reduced.

Distributed radio communication base station system, base band unit, remote radio unit, and method for operating distributed radio communication base station system

A base station apparatus includes at least one remote unit apparatus including at least one antenna; and a central unit apparatus connected to each remote unit via a transmission path. The remote antenna receives a wireless transmission signal from at least one wireless terminal including at least one antenna. The remote unit includes a channel estimation unit functioning between the terminal antenna and the remote antenna, using a reception signal received by the remote unit antenna; a reception signal processing unit that detects a reception signal corresponding to the transmission signal, using the channel information estimated by the channel estimation unit; a decoding unit that decodes each signal detected by the reception signal processing unit; and an inter-unit transmission unit that transmits each signal decoded by the decoding unit to the central unit. The central unit is provided with an inter-unit receiving unit and a signal selection unit.

Base station apparatus, wireless communication system, and communication method

A communication system and method comprising a higher-network apparatus and a lower-network apparatus connected through a PON system, which transfers uplink data from the lower-network apparatus to the higher-network apparatus at high speed so as to meet severe conditions required for a delay time between the higher-network apparatus and the lower-network apparatus. The method including a scheduling execution process in which a higher-network apparatus performs scheduling for uplink communication from each of the lower-network apparatus to the device itself and an uplink data transmission permission process in which the higher-network apparatus calculates a transmission time and a transmission permission amount of uplink data transmitted from an ONU to OLT based on the scheduling for uplink communication and notifies the OLT.

Optical communication system, optical communication method, higher-network apparatus, and optical line terminal

This invention discloses an optical burst transmission system in which an optical generator generates Type 1 lightwaves having different wavelengths corresponding to transmission lines and having undergone intensity modulation with obtained data; a broad spectrum optical generator generates, by incorporating Type 2 lightwaves, a Type 3 lightwave using a fewer light emitting devices than the number of the Type 1 lightwaves, each Type 2 lightwaves having a corresponding wavelength apart from Type 1 lightwave's wavelength with an FSR interval and having undergone the intensity modulation with clock signals; an optical multiplexer multiplexes the Type 1 and Type 3 lightwaves to output the combination to each transmission line; and an optical routing unit extracts, from the combination, pairs of one Type 1 lightwave and one Type 2 lightwave having the corresponding wavelength, and guides pairs to each transmission line corresponding to the Type 1 lightwave's wavelength in each pair.

Low-cost optical burst transmission system, apparatus, and method

In a transmitter side in an optical transmission system, an input binary signal is converted into a duobinary signal, and the duobinary signal is applied to an optical modulation device which provides an optical intensity modulation signal, wherein the optical intensity for a center value of the duobinary signal is a minimum, the optical intensity for the other two values of the duobinary signal is a maximum, and an optical phase for those two values is opposite to each other. In a receiver side, simple direct detection is carried out for receiving optical signal through an optical transmission line to provide a demodulated binary signal. Thus, an original binary signal is recovered without a duobinary decoder and receiver sensitivity degradation. In the optical transmission system, an optical carrier frequency component in a signal spectrum is suppressed, a signal bandwidth of the modulated light is reduced in half to that of a prior art, so an optical transmission system for long distance, high bit rate and large traffic capacity is obtained.

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Yokosuka, Japan

Shigeru Kuwano