Oki Electric Industry Co., Ltd.

Of Networks Co., Ltd.

Hideaki Tamai

Masayuki Kashima

Satoshi Furusawa

Akiya Suzuki

Akihiro Takahashi

Saeko Oshiba

Yasuyuki Kuroda

Ryuji Hisano

A bandwidth allocator for communicating with communication terminals by transmitting and receiving data packets over a line having its communication bandwidth divided into periods of time of a predetermined length. The allocator includes a controller controlling allocation of the bandwidth by using allocation grants as the periods of time. The controller includes a scheduler scheduling the allocation grants so as to cause one allocation grant to partially overlap as a shared grant with another allocation grant adjacent to the one allocation grant. Thus, the bandwidth allocator can minimize allocation loss, otherwise caused by no allocation to an allocation grant, and improve the use efficiency of the bandwidth.

Bandwidth allocator using a shared grant to schedule allocation grants and a method therefor

There is provided an optical line terminal that dynamically allocates communication bandwidth to a plurality of optical network units in an optical communication network, the optical line terminal including a minimum bandwidth allocation unit calculating allocation bandwidth of the plurality of optical network units based on bandwidth request information notified by the plurality of optical network units, a comparison unit comparing an allocation cycle given as the sum total of allocation bandwidth allocated to the plurality of optical network units respectively with a predetermined threshold value, a best-effort bandwidth allocation unit calculating remaining bandwidth as best-effort bandwidth of the plurality of optical network units when the allocation cycle is less than the threshold value, and a bandwidth allocation unit allocating communication bandwidth of the plurality of optical network units based on the allocation bandwidth and the best-effort bandwidth.

Optical line terminal, dynamic bandwidth allocation method, and optical communication network

In an optical line terminal connectable to optical network units in an optical communication network, an receiver converts an upstream optical signal, received from an optical network unit, into a corresponding upstream electric signal and then derives an upstream control signal controlling the optical line terminal from the upstream electric signal. A controller generates a power control signal switching on or off power supply to the receiver on the basis of the upstream control signal, and a power feeder switches on or off the power supply to the receiver in response to the power control signal. Thus, the optical line terminal can reduce the waste of standby electricity.

Optical line terminal for optoelectrically converting a signal and a method therefor

An optical communications network that is composed of one station-side equipment being connected to plural subscriber-side equipments. The station-side equipment refers to downstream data signals and prepares transmission plans, and generates downstream control signals that include the transmission plans, and converts downstream signals, that include the downstream data signals and the downstream control signals to which identifiers indicating the subscriber-side equipments that are addressees are assigned, into downstream optical signals, and sends the downstream optical signals out toward the subscriber-side equipments. The subscriber-side equipment converts downstream optical signals into downstream electric signals, and refers to identifiers and extracts downstream electric signals addressed to itself, and reads the transmission plans, and generates timer control signals including information of receiving start times and receiving stop times, and, on the basis of the timer control signals, opens and closes a path connecting a receiving section and an electricity supply section.

Optical communications network, power supply controlling method, station-side equipment, subscriber-side equipment, and semiconductor chip

A code division multiplex signal transmitter includes an operational circuit, a modulator unit and a multiplexer. The operational circuit adds up input transmission data on channels to produce resultant added data and modulates pieces of bit transmission data which are indicative of the values of the respective bits of the added data, when expressed in binary form, the pieces of bit transmission data being equal in number to the M bit positions of the added data expressed in binary form. The modulator unit includes modulators corresponding in number to the M bit positions of the added data in the binary form. A k-th modulator, where k is an integer of 1 to M, inclusive, modulates a k-th piece of bit transmission data to produce a k-th bit modulated signal whose amplitude level is 2. The multiplexer multiplexes first to M-th bit modulated signals to produce a code division multiplex signal.

CDM signal transmitter with modulators reduced in number and a method therefor

There is provided a propagation delay time adjustment method for adjusting the propagation delay time occurring within a reception circuit for each channel of a center node device configuring a 1-to-N communications system in which communication is performed between the center node device and N (N being an integer of 2 or more) individual edge node devices using a Synchronous Code Division Multiplexing method, the center node device comprising a main control section, and each of the edge node devices comprising an auxiliary control section that controls the propagation delay time in cooperation with the main control section, the transmission delay time adjustment method comprising: transmission permission signal transmitting; transmission controlling; reception phase controlling; reception validity determining; optimum reception phase determining; and reception phase setting in which the main control section sets the optimum reception phase as the reception phase for the reception circuit.

Propagation delay time adjustment method, propagation delay time adjustment system, propagation delay time adjustment device, storage medium stored with propagation delay time adjustment program, and node device

An optical communications network in which one optical line terminal is connected to multiple optical network units and in which code division multiplexing communication is carried out between the optical line terminal and the optical network units. The optical intensities of upstream optical signals transmitted from each optical network unit are made constant at the time of multiplexing by an optical directional coupler, and the optical intensity of a downstream optical signal received by an optical network unit and an upstream optical signal received by the optical line terminal is contained within a dynamic range. Each optical network unit is provided with a variable optical attenuator that is common for an upstream optical signal and a downstream optical signal. The upstream optical signal and the downstream optical signal are attenuated by an equal attenuation. Moreover, the optical line terminal controls the attenuation at the variable optical attenuator.

Optical communications network and intensity adjustment method for optical communications network

N channels of encoded data are added into added data, which is compared with a first threshold of 2&#x2212;A and a second threshold of 2&#x2212;1, where M is the number of the bit positions of the binary representation of N and A is defined by 2&#x2212;(N+1). When the added data is less than the first threshold, it is selected. When the added data falls between the first and second thresholds, inclusive, either the added data or shifted data, obtained by adding A to the added data, is selected. When the added data exceeds the second threshold, the shifted data is selected. Based on output data representing the values of the respective bit positions of the binary representation of the selected data, the k-th output data, where k is a natural number less than M, is amplified into k-th amplified data having an amplitude level of 2, and the M-th output data is amplified into M-th amplified data having an amplitude level of 2&#x2212;A. The first to M-th amplified data are multiplexed into a CDM signal.

Code division multiplex signal transmitter and code division multiplexing method with amplifying circuits reduced in number

A code division multiplex transmitting and receiving apparatus has a transmitting apparatus with two coders per channel and terminal units with two matched filters each. One coder and one matched filter employ one spreading code; the other coder and the other matched filter employ another spreading code. The two coded signals output in parallel by the two coders are converted to a single serial signal before being multiplexed. The two matched filters sample alternate chips in the multiplexed signal. The two coders can be supplied with different data signals to double the transmission capacity, or with the same data signal to double the transmission distance. The outputs of the two matched filters are processed separately in the former case and are combined in the latter case.

Code division multiplex transmitting and receiving apparatus and method

In a communication network which performs transmission from a plurality of first communication devices to a single second communication device using a synchronous code division multiplexing technique, the phases of signals transmitted from the first communication devices are synchronized easily. The first communication devices control the transmission phase of spread modulated signals using phase control information received from the second communication device. A repeater generates a code division multiplexed signal by superposing the spread modulated signals transmitted respectively from the first transmission devices. The second transmission device demultiplexes the code division multiplexed signal received from the repeater, determines the optimum phase of the demultiplexed signals, and transmits the determined optimum phase to the first transmission devices as the phase control information.

Communication network using synchronous code division multiplexing method

A transmission unit comprises an optical pulse train generation unit, first channel encoded optical pulse signal generation unit, second channel encoded optical pulse signal generation unit, third channel encoded optical pulse signal generation unit, and fourth channel encoded optical pulse signal generation unit; the second and fourth channels further comprise polarization controllers respectively. By means of these polarization controllers, a polarization control step is executed in which the planes of polarization of first encoded optical pulse signals of the second and fourth channels are rotated by 90&#xb0;. By executing the polarization control step, the directions of the planes of polarization of the first decoded optical pulse signals of adjacent channels in the reception unit can be caused to be mutually orthogonal.

Optical code division multiplexing transmission/reception method and optical code division multiplexing transmission/reception device

In 1 to N communication based on code division multiplexing, ranging is performed by following the first to ninth steps. First step: all the optical network units are set to standby status. Second step: first and second optical network units are set to transmission enable status. Third step: the phase shift amount is set for the variable phase shifters of the first and second optical network units. Fourth step: reception of a fixed signal is attempted in the optical line terminal. Fifth step: if the fixed signal is not received, processing returns to the second step, and if received, the phase amount of the variable phase shifter is defined and fixed. In the sixth to ninth steps, an operation the same as the first to fifth steps is performed for the third to N-th optical network units. In these steps, the optical line terminal receives the i-th reply signal (i is an integer in the 1 to (n&#x2212;1) range and i&#x2260;n) sent from at least one i-th optical network unit out of the first to (n&#x2212;1)th optical network units, and sequentially defines and fixes the phase shift amount of the variable phase shifter of the third to N-th optical network units.

Ranging method for communication system between optical line terminal and plurality of optical network units

A clock regeneration circuit includes a half-bit delay device that outputs a half-bit delayed signal B of a multi-level input signal A, a one-bit delay device that outputs a one-bit delayed signal C of the signal A, an adder, an attenuator that forms an threshold signal, an XOR circuit, and a BPF that outputs a clock signal with a frequency corresponding to a bit rate of the XOR signal. The XOR signal is calculated as an XOR of a two-level input signal F, which is a logical zero when a level of the signal A is no more than a level of the threshold signal and otherwise is a logical one, and a two-level input signal G, which is a logical zero when a level of the signal B is no more than the level of the threshold signal and otherwise is a logical one.

Clock regeneration circuit

A feature of a wavelength conversion device of this invention is the board range of selection of wavelengths which can be obtained by conversion. A wavelength conversion device of this invention comprises an SC light generation portion, which receives an excitation light pulse output from an excitation light pulse source and generates SC light, and an optical wavelength filterwhich filters the SC light. An excitation light pulse source generates an excitation light pulse, of central wavelength &#x3bb;. When the excitation light pulse generated by the excitation light pulse source is incident on the SC medium, SC light having a flat spectral shape over the range from wavelength &#x3bb;to wavelength &#x3bb;(where &#x3bb;&#x3c;&#x3bb;) is generated. The optical wavelength filter has a characteristic such that the filtering transmitted central wavelengths are &#x3bb;, &#x3bb;, &#x3bb;, . . . , &#x3bb;(where n is a natural number). A further feature is that the following conditions (1) and (2-1), (2-2), . . . , (2-n) between the wavelength &#x3bb;, the wavelength &#x3bb;, the wavelength &#x3bb;, and the wavelengths &#x3bb;, &#x3bb;, &#x3bb;, . . . , &#x3bb;(where n is a natural number) are satisfied.&#x3bb;&#x3c;&#x3bb;&#x3c;&#x3bb;&#x2003;&#x2003;(1)&#x3bb;&#x3c;&#x3bb;&#x3c;&#x3bb;&#x2003;&#x2003;(2-1)&#x2022;&#x2022;&#x2022;&#x3bb;&#x3c;&#x3bb;&#x3c;&#x3bb;&#x2003;&#x2003;(2-n)

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Kanagawa, Japan

Hideaki Tamai