2149results about "Radio-over-fibre" patented technology

There is disclosed a radio communication system in which a constitution of a base station and further a control station can be simplified. A radio communication system according to the present invention converts a received signal received by a plurality of antenna elements in a base station to a signal of different frequency band, and then conflates the converted signal in order to generate sub-carrier wave multiplex signal. The signal is converted to an optical signal, and then the optical signal is transmitted to a control station via an optical fiber. Or the control station performs weighting to phase of the transmitted signal transmitted from a plurality of antennas of a base station, and then performs frequency conversion to different frequency band, and then conflates the converted signal in order to generate the sub-carrier wave multiplex signal. The signal is converted to an optical signal, and then an optical signal is transmitted to the base station side via the optical fiber. The control station and the base station divides the received sub-carrier wave multiplex signal by each frequency band, and then the frequency of the divided signals are converted to the same frequency band in order to generate the transmitted / received signal of each antenna element. By such a constitution, it is possible to reduce constituent of the optical transmission components to the minimum and to simplify the constitution of the base station. Furthermore, it is possible to maintain the relative phase difference and the relative intensity of the transmitted / received signal of each antenna element. Because of this, it is possible to estimate an arrival direction of the received signal and to control radiation beam pattern of the transmitted signal.

A distributed antenna system is provided for communicating with a plurality of base stations. The distributed antenna system includes a system controller and a master unit communicating with at least one of the plurality of base stations. A remote unit communicates over a high data rate media with the master unit and / or a downstream remote unit. Alternatively, the distributed antenna system includes a controller and a digital time / space crosspoint switch controlled by the controller. A digitizing transceiver is in communication with the digital time / space crosspoint switch. The crosspoint switch is configured to transmit and receive digital data through the digitizing transceiver.

Optical fiber-based distributed antenna systems that support multiple-input, multiple-output (MIMO) antenna configurations and communications. Embodiments disclosed herein include optical fiber-based distributed antenna system that can be flexibly configured to support or not support MIMO communications configurations. In one embodiment, first and second MIMO communication paths are shared on the same optical fiber using frequency conversion to avoid interference issues, wherein the second communication path is provide to a remote extension unit to remote antenna unit. In another embodiment, the optical fiber-based distributed antenna systems may be configured to allow to provide MIMO communication configurations with existing components. Existing capacity of system components are employed to create second communication paths for MIMO configurations, thereby reducing overall capacity, but allowing avoidance of frequency conversion components and remote extension units.

A wireless communication system comprises a base station controller and a base station interface connected to the base station controller by a central optical fiber. The base station interface may include a flexible wavelength router. At least one base station is connected to the base station interface, and the central optical fiber carries at least one communication channel associated with an optical signal having one of a plurality of wavelengths. The base station interface selectively provides a communication path between the base station controller and at least one base station using at least one communication channel.

An access system and method for transmitting Ethernet signals and mobile communication signals. The system includes a near-end host unit and remote-end user units. Through the near-end host unit, the Ethernet signals and mobile communication signals can be combined. The near-end and remote-end host units are connected through four pairs of twisted pairs. The combined Ethernet and mobile communication signals are sent to a user terminal for providing broadband access service and wireless access service. Premises network resources can be used without re-laying category 5 cables, so the investment is less and it is quick and convenient to provide service. Furthermore there needs to be added only one host unit beside the optical network unit equipment, and replace the user terminal simultaneously. Power is not needed to be taken at the user's home. The placement position of the terminal is flexible without being limited by the power-taking positions.

Signal transmission systems for second and third generation mobile communications networks are described. A signal distribution system comprises a plurality of rf transmitters for serving a plurality of network cells. The system is characterised by a multiplexer coupled to the transmitters for multiplexing the transmitter outputs, a signal transporter for transporting the multiplexed signals to each of the network cells, and a multiplexed signal receiver at each cell for selecting and receiving a signal from a transmitter serving the cell. The invention also provides a complementary signal reception system, and corresponding methods. Preferably, the multiplexed signals are transported over a fibre optic network such as an existing cable TV network. The system simplifies the deployment of network infrastructure for third generation mobile communications systems.

The present disclosure is a novel utility of a software defined radio (SDR) based Distributed Antenna System (DAS) that is field reconfigurable and support multi-modulation schemes (modulation-independent), multi-carriers, multi-frequency bands and multi-channels. The present disclosure enables a high degree of flexibility to manage, control, enhance, facilitate the usage and performance of a distributed wireless network such as flexible simulcast, automatic traffic load-balancing, network and radio resource optimization, network calibration, autonomous / assisted commissioning, carrier pooling, automatic frequency selection, frequency carrier placement, traffic monitoring, traffic tagging, pilot beacon, etc. As a result, the SDR DAS can increase the efficiency and traffic capacity of the operators' wireless network.

There is disclosed a radio communication system in which a constitution of a base station and further a control station can be simplified. A radio communication system according to the present invention converts a received signal received by a plurality of antenna elements in a base station to a signal of different frequency band, and then conflates the converted signal in order to generate sub-carrier wavemultiplex signal. The signal is converted to an optical signal, and then the optical signal is transmitted to a control station via an optical fiber. Or the control station performs weighting to phase of the transmitted signal transmitted from a plurality of antennas of a base station, and then performs frequency conversion to different frequency band, and then conflates the converted signal in order to generate the sub-carrier wave multiplex signal. The signal is converted to an optical signal, and then an optical signal is transmitted to the base station side via the optical fiber. The control station and the base station divides the received sub-carrier wave multiplex signal by each frequency band, and then the frequency of the divided signals are converted to the same frequency band in order to generate the transmitted / received signal of each antenna element. By such a constitution, it is possible to reduce constituent of the optical transmission components to the minimum and to simplify the constitution of the base station. Furthermore, it is possible to maintain the relative phase difference and the relative intensity of the transmitted / received signal of each antenna element. Because of this, it is possible to estimate an arrival direction of the received signal and to control radiation beam pattern of the transmitted signal.

A transceiver architecture for wireless base stations wherein a broadband radio frequency signal is carried between at least one tower-mounted unit and a ground-based unit via optical fibers, or other non-distortive media, in either digital or analog format. Each tower-mounted unit (for both reception and transmission) has an antenna, analog amplifier and an electro-optical converter. The ground unit has ultrafast data converters and digital frequency translators, as well as signal linearizers, to compensate for nonlinear distortion in the amplifiers and optical links in both directions. In one embodiment of the invention, at least one of the digital data converters, frequency translators, and linearizers includes superconducting elements mounted on a cryocooler.

A distributed antenna system is provided for communicating with a plurality of base stations. The distributed antenna system includes a system controller and a master unit communicating with at least one of the plurality of base stations. A remote unit communicates over a high data rate media with the master unit and / or a downstream remote unit. Alternatively, the distributed antenna system includes a controller and a digital time / space crosspoint switch controlled by the controller. A digitizing transceiver is in communication with the digital time / space crosspoint switch. The crosspoint switch is configured to transmit and receive digital data through the digitizing transceiver.

An optical communications network includes a terminal which can simultaneously receive and modulate an optical signal. The terminal includes an optical modulator which is controlled by varying the bias voltage applied to it.

Optical network termination systems, devices and methods including an optical network terminal (ONT) having a processor in communication with an external optical fiber. The ONT processors further in communication with a wireless access point and at least one electrically conductive internal transport medium, both providing for the communication of telecommunication signals with devices located within a customer premises. The wireless access point and in certain instances the processor are back powered over the electrically conductive internal transport medium from AC power within the premises. In certain embodiments, the wireless access point communicates with devices within the premises over a distributed antenna.

A divider / combiner unit combines RF signals, then converts the combined signal into an optical signal and sends it over an optical fiber. N radio access units each convert the optical signal received from the optical fiber into an RF signal and transmits it from an antenna, and each radio access unit converts an RF signal received by the antenna into an optical signal and sends it over an optical fiber to the divider / combiner unit. The divider / combiner unit converts the received optical signal into RF signals and outputs them. This system is operated as plurality of communication systems in common to them in correspondence to a plurality of input / output terminals of the divider / combiner unit.

A signal transmitting apparatus for an optical base station is disclosed. According to the invention, a base station outputs a digital IQ signal to an optical connecting unit. The optical connecting unit processes the digital IQ signal digitally, and transmits the digital signal over an optical network to a remotely located optical base station. The remote station digitally processes the signal before converting to an RF signal for transmission. The invention advantageously decreases signal loss and noise associated with analog processing in the optical connecting units and remote stations in the related art. System reliability is also improved.

A radio-over-fiber (RoF) system and method for controlling a transmission time is provided. In a Time Division Duplex (TDD) wireless communication system comprising a Base Station (BS) having a donor and a remote connected thereto via am optical fiber, upstream and downstream Radio Frequency (RF) signals are transmitted and received, and by reliably transmitting a switch control signal to the remote and simultaneously compensating for a transmission time delay occurring in the optical cable, time synchronization of the upstream and downstream RF signals transmitted and received via antennas of the BS and the remote is controlled, thereby efficiently increasing the performance of a TDD wireless service system.

Embodiments of the present invention exploit the existing capabilities of the Ethernet Passive Optical Network (EPON) MAC layer, designed for fiber optics communications, to provide a low cost MAC layer with upper layer connectivity over a hybrid fiber coaxial (HFC) network. In particular, embodiments allow for the EPON MAC to be used end-to-end (i.e., from an optical line terminal (OLT) to a coaxial network unit (CNU)) in a HFC network, thereby fully leveraging the packet processing capabilities, QoS functions, and management features of the EPON MAC. Furthermore, embodiments enable unified provisioning and management for both fiber and coaxial network units in a HFC network.

A Fiber-wireless uplink consists of a wireless channel followed by a radio-over-fiber (ROF) link. Typically, nonlinear distortion of the ROF link is the major concern when the radio frequency is only a few GHz. This especially severe in the uplink, because of the multipath fading of the wireless channel. A Hammerstein type decision feedback equalizer is described for the fiber wireless uplink, that compensates for nonlinear distortion of the ROF link as well as linear dispersion of the wireless channel. Since the linear and nonlinear parts of the receiver are separated, tracking the fast changing wireless channel is virtually independent of compensating for the relatively static nonlinearity. Analytical results show that the receiver provides excellent compensation with notably less complexity.

A radio over fiber link apparatus for transmitting / receiving radio frequency up / downlink signals in a TDD mobile communication system. The radio over fiber link apparatus includes a center site for receiving radio frequency signals from an access point of the mobile communication system. The center site has a first electro-optic converter for converting the radio frequency signals into optical signals, bias control of the first electro-optic converter being performed based on the switching of TDD signals; and a remote for transmitting the radio frequency signals to a mobile communication terminal through an antenna. The remote site has a first photoelectric converter for converting the optical signals transmitted through an optical fiber from the center site into radio frequency signals.

An apparatus and method for measuring and compensating for delay between a main base station and a remote base station interconnected by an optical cable. The main base station inserts a test pattern into an overhead part of an SDH frame to transmit the SDH frame to the remote base station, receives the SDH frame looped back by the remote base station to detect the test pattern, and measures propagation delay according to the test pattern. At least one frame alignment word (FAW) is detected at a predetermined position in the received SDH frame, and a delay error is calculated according to FAW detection information. The measured propagation delay with the delay error is compensated and produces propagation delay caused by the optical cable. A modulator / demodulator (MODEM) compensates for delay of a baseband signal to be transmitted to the remote base station.

Disclosed is an all-optical frequency upconverter in a radio-over-fiber system that outputs upconverted optical radio frequency (RF) signals using an optical intermediate frequency signal and an optical local oscillation signal. The all-optical frequency upconverter includes a semiconductor optical amplifier that mixes the optical intermediate frequency signal with the optical local oscillation signal through four wave mixing, and an optical filter that filters a plurality of frequency component signals, which are generated through the four wave mixing, to extract optical RF signals. According to the invention the system configuration can be made simple, and wide LO and IF frequency bandwidths can be provided.

Aspects of the disclosure relate generally to a circuit for sustaining an radio frequency (RF) modulated optical signal. The circuit may comprise a self injection locking component having a fiber optic delay line over which a portion of the optical signal propagates. The circuit may also comprise a self phase locked loop component having at least two fiber optic cables having different lengths and over which another portion of the optical signal propagates and a phase detector coupled to the at least two fiber optic cables and configured to determine a phase difference between the signals propagating over one of the respective fiber optic cables. The circuit may further comprise a voltage controlled oscillator configured to generate a stable oscillating signal in response to signals generated by each of the self injection locking and self phase locked loop components, the stable oscillating signal being configured to sustain the optical signal.

An optical fiber radio transmission system is provided which is capable of considerably improving the received dynamic range of radio signals and, in addition, is capable of optically transmitting radio signals while preventing the deterioration of transmission performance and the loss of linearity of an input signal more easily. A received level detection section 111 detects which one of predetermined levels, i.e., Level I, Level II, and Level III, the received level of a radio signal received by an antenna 400 falls under. A signal control section 112 performs an amplification / attenuation process on the radio signal in accordance with the detected level. A control information sending section 113 superimposes control information indicating the detected level on a primary signal obtained after the amplification / attenuation process. This signal is converted to an optical signal and transmitted. An optical to electrical conversion section 211 converts the optical signal received from a transmitting unit to an electrical signal. A control information extraction section 212 extracts the level from the control information, which has been superimposed on the primary signal. A signal control section 213 performs an amplification / attenuation process on the primary signal in accordance with the extracted level.

Power distribution modules capable of “hot” connection and / or disconnection in distributed antenna systems (DAS), and related components, power units, and methods are disclosed. The power distribution modules are configured to distribute power to a power-consuming DAS component(s), such as a remote antenna unit(s) (RAU(s)). By “hot” connection and / or disconnection, it is meant that the power distribution modules can be connected and / or disconnected from a power unit and / or a power-consuming DAS component(s) while power is being provided to the power distribution modules. Power is not required to be disabled in the power unit before connection and / or disconnection of power distribution modules. As a non-limiting example, the power distribution modules may be configured to protect against or reduce electrical arcing or electrical contact erosion that may otherwise result from “hot” connection and / or connection of the power distribution modules.

Methods and systems for monolithic integration of photonics and electronics in CMOS processes are disclosed and may include fabricating photonic and electronic devices on a single CMOS wafer with different silicon layer thicknesses. The devices may be fabricated on a semiconductor-on-insulator (SOI) wafer utilizing a bulk CMOS process and / or on a SOI wafer utilizing a SOI CMOS process. The different thicknesses may be fabricated utilizing a double SOI process and / or a selective area growth process. Cladding layers may be fabricated utilizing one or more oxygen implants and / or utilizing CMOS trench oxide on the CMOS wafer. Silicon may be deposited on the CMOS trench oxide utilizing epitaxial lateral overgrowth. Cladding layers may be fabricated utilizing selective backside etching. Reflective surfaces may be fabricated by depositing metal on the selectively etched regions. Silicon dioxide or silicon germanium integrated in the CMOS wafer may be utilized as an etch stop layer.

An optical network for bi-directional wireless communication is disclosed. The optical network includes a remote antenna unit for converting a downlink optical signal into a downlink radio signal, transmitting the downlink radio signal wirelessly, and converting an uplink radio signal received wirelessly into an uplink optical signal. An optical line is used as a transmission medium of the downlink optical signal and the uplink optical signal. The optical network also includes a central base station including a circulator linked to the remote antenna unit through the optical line, so that the central base station outputs the downlink optical signal to the remote antenna unit through the circulator and detects the uplink optical signal inputted through the circulator.

An optical / wireless transceiver device is operable to convert an input optical signal to an outgoing radio frequency signal, and to convert an incoming radio frequency signal to an output optical signal.