An apparatus is provided that includes an optical noise generator and a noise combiner. The noise generator is configured to produce an optical signal having a noise channel. The noise combiner is configured to combine an optical data channel with the noise channel received at one or more add ports to produce an optical output signal. A controller is configured to operate the noise generator or the noise combiner to provide a variable bandwidth of added noise combined with the optical data channel.

An optical transmission device includes: a memory; and a processor coupled to the memory; the processor: generate a first symbol by mapping a transmission data series to a first signal point which belongs to a first group within a signal space defined with regard to characteristics of an optical carrier wave of the transmission data series; generate a second symbol by mapping the transmission data series to a second signal point belonging to a second group; calculate a perturbation quantity of a signal electric field for each of the first and second symbols based on signal electric field vector information of a symbol which is generated before the first symbol and the second symbol; and determine, as a transmission signal, a symbol having a smaller perturbation quantity between the first symbol and the second symbol.

According to one embodiment, a communication repeater system includes a master station device and radio frequency units which convert a signal from each of base station systems into an optical digital signal for transmission to the master station device. The base station systems establish communication by time division duplex scheme. The communication repeater system repeats communication between a mobile communication terminal device and each base station system via a corresponding one of slave station devices. A setter sets, as reference transmission/reception switching timing, a transmission/reception switching timing between the master station device and one of the radio frequency units corresponding to one of the base station systems which is first connected to the communication repeater system. A corrector corrects variation in the transmission/reception switching timing in accordance with the reference transmission/reception switching timing.

According to one embodiment, a communication repeater system includes a master station device and radio frequency units which convert a signal from each of base station systems into an optical digital signal for transmission to the master station device. The base station systems establish communication by time division duplex scheme. The communication repeater system repeats communication between a mobile communication terminal device and each base station system via a corresponding one of slave station devices. A setter sets, as reference transmission/reception switching timing, a transmission/reception switching timing between the master station device and one of the radio frequency units corresponding to one of the base station systems which is first connected to the communication repeater system. A corrector corrects variation in the transmission/reception switching timing in accordance with the reference transmission/reception switching timing.

Apparatus for providing communication between ground-based User Equipment (UE) and at least one core network and a method for providing wireless communication between ground-based User Equipment (UE) and at least one core network are disclosed. The apparatus for providing communication between ground-based User Equipment (UE) and at least one core network comprises a plurality of low earth orbit satellites each comprising at least one satellite-based optical transmitter element and at least one satellite-based optical receiver element for providing at least one optical communication link; and at least one aerial vehicle comprising at least one aerial vehicle based optical transmitter element and at least one aerial vehicle based optical receiver element for providing at least one optical communication link and at least one directional antenna for providing a wireless communication link to a ground-based station and/or mobile UE.

In an optical transceiver, an optical transmitter coupled to a reconfigurable optical channel-add apparatus has first and second add paths, an add micro-ring resonator, and first and second optical attenuators, reconfigurable to selectively block an optical channel from an optical transmitter in one of the first and second add paths. The add micro-ring resonator is reconfigurable selectively to add an optical channel from the first add path to an optical waveguide to travel towards the first add-drop port or to add an optical channel from the second add path to the optical waveguide to travel towards the second add-drop port. An optical receiver is coupled to a reconfigurable optical channel-drop apparatus having a drop micro-ring resonator, and first and second drop paths. The drop micro-ring resonator is reconfigurable selectively to drop an optical channel travelling from the first add-drop port from the optical waveguide to the first drop path or to drop an optical channel travelling from the second add-drop port from the optical waveguide to the second drop path.

Described are systems, devices, and techniques for extending wireless networks and associated systems, devices, and techniques for determination of optimal locations of a wireless range extender, such as by evalauating a quality of a wireless signal originating from a wireless gateway or access device and determining whether an alternative placement of a wireless range extender would result in improved quality. Also described are systems, devices, and techniques for automatically grouping multiple bands of a single wireless access device as well as systems, devices, and techniques that simplify connection of wireless devices to a wireless access device, such as by evaluating wireless messages transmitted on different bands to determine that the wireless messages originate from the same wireless access device.

A free-space optical communication link is proposed that utilizes phase-sensitive amplification of the received optical signal at the input to the receiver portion of the link. The transmitter component of the FSO link generates an idler signal that is transmitted through free space with the original data signal and used at the PSA in conjunction with a pump wave to impart gain onto the received information signal. The PSA performs four-wave mixing (FWM) of the data, idler and pump to create the amplified data signal. In one embodiment, the pump wave used to generate the idler at the transmitter is sent through free space with the information and idler signals and used by the PSA to perform amplification. Alternatively, the PSA may use a co-located pump laser, in combination with the received idler signal, to perform the phase-sensitive amplification process.

A proactive and non-obtrusive channel probing scheme is provided to accurately predict channel power, gain, and optical signal to noise ratio (OSNR) without disrupting the existing connections. In one example, using a probe signal with 5 s pulse duration in a single-hop network, rapid wavelength switching is achieved with power excursions less than or equal to 0.2 dB for different loading configurations.

A distributed Automatic Power Optimization (APO) system and method are provided. The distributed APO system includes: one or more APO modules and a network management system. The one or more APO modules belong to one or more pre-divided APO links. Each APO module in the one or more APO modules belongs to only one APO link. The APO module is configured to, when the APO link to which the APO module belongs is triggered to perform power regulation, regulate a power attenuation or a gain between the two adjacent stations corresponding to the APO module and report a regulation result. The network management system is configured to, when learning that all of one or more APO modules in one APO link are successful in regulation, if there is a next APO link of the APO link, trigger the next APO link of the APO link to perform power regulation.