Before the emergence of ultra-wideband (UWB) radios, widely used wireless communications were based on sinusoidal carriers, and impulse technologies were employed only in specific applications (e.g. radar). In 2002, the Federal Communication Commission (FCC) allowed unlicensed operation between 3.1–10.6 GHz for UWB communication, using a wideband signal format with a low EIRP level (−41.3dBm/MHz). UWB communication systems then emerged as an alternative to narrowband systems and significant effort in this area has been invested at the regulatory, commercial, and research levels.

IEEE Transactions on Microwave Theory and Techniques and Antennas and Propagation Announce a Joint Special Issue on Ultra-Wideband (UWB) Technology

The integration of optical and wireless systems is considered to be one of the most promising solutions for increasing the existing capacity and mobility as well as decreasing the costs in next-generation optical access networks. In this paper, several key enabling technologies for hybrid optical-wireless access networks are described, including optical millimeter-wave (mm-wave) generation, upconversion, and transmission in a downlink direction, and full-duplex operation based on wavelength reuse by using a centralized light source in an uplink direction. By employing these enabling technologies, we design and experimentally demonstrate an optical-wireless testbed that is simultaneously delivering wired and wireless services in the integrated optical-wireless and wavelength-division-multiplexing passive-optical-network access networks. The actual applications consisting of 270-Mb/s uncompressed standard-definition TV signal and 2.5-Gb/s data channels for downstream are successfully transmitted over a 25-km fiber and a 10.2-m indoor wireless link with less than a 1.5-dB power penalty. The results show that this integrated system is a practical solution to deliver superbroadband information services to both stationary and mobile users.

Key Enabling Technologies for Optical–Wireless Networks: Optical Millimeter-Wave Generation, Wavelength Reuse, and Architecture

Aspects of the subject disclosure may include, for example, a host node device having a terminal interface that receives downstream channel signals from a communication network and send upstream channel signals to the communication network. An access point repeater launches the downstream channel signals as guided electromagnetic waves on a guided wave communication system and to extract a first subset of the upstream channel signals from the guided wave communication system. A radio wirelessly transmits the downstream channel signals to at least one client node device and to wirelessly receive a second subset of the upstream channel signals from the at least one client node device. Other embodiments are disclosed.

Host node device and methods for use therewith

Optical fiber-based wireless systems and related components and methods are disclosed. The systems support radio frequency (RF) communications with clients over optical fiber, including Radio-over-Fiber (RoF) communications. The systems may be provided as part of an indoor distributed antenna system (IDAS) to provide wireless communication services to clients inside a building or other facility. The communications can be distributed between a head end unit (HEU) that receives carrier signals from one or more service or carrier providers and converts the signals to RoF signals for distribution over optical fibers to end points, which may be remote antenna units (RAUs). In one embodiment, calibration of communication downlinks and communication uplinks is performed to compensate for signal strength losses in the system.

Optical fiber-based distributed antenna systems, components, and related methods for calibration thereof

A multiple-input multiple-output (MIMO) capable system is contemplated. The communication system may include a signal processor configured to separate an input stream into multiple signal paths to facilitate simultaneous transport through a communication medium. The capability to simultaneously transmit multiples signal paths may be beneficial in order to maximize throughput and/or minimize expense.

Multiple-input multiple-output (mimo) communication system

A distributed antenna system includes a multiple-input and multiple-output (MIMO) base station configured to output at least a first signal and a second signal. At least one master unit communicates with the MIMO base station. At least one remote unit communicates with the master unit. At least one antenna is coupled with the remote unit for receiving signals from the remote unit. A hybrid coupler is coupled between the remote unit and antenna and is configured to receive the first signal Ch1 and the second signal Ch2 from the remote unit on respective first and second ports and to provide an output signal on at least one output port. The output signal includes at least a portion of the first signal and at least a portion of the second signal. The antenna is coupled with the output port.

Distributed antenna system for MIMO signals

A method and apparatus for determining placement of a plurality of antennas of a distributed antenna system for handling MIMO signals includes, at a first location, simulating the communication of a first MIMO signal by a first remote unit over an air interface in an environment and, at a second location, simulating the communication of a second MIMO signal by a second remote unit over an air interface in the environment. The first and second locations are arranged within the environment to provide overlapping signal coverage of both the first MIMO signal and the second MIMO signal at a third location in the environment. Analysis is made of at least an imbalance of received power between the first and second MIMO signals within the environment at a third location in order to determine whether a desired capacity for MIMO communications with the system has been achieved at the third location.

Distributed antenna system for mimo communications

Harmonic and intermodulation distortion contributions generated by modal noise in radio over multimode fiber (RoMMF) systems for in-building wireless coverage are reviewed. The role played by the launching technique and by the optical transmitter and receiver in an intensity-modulated direct-detection RoMMF system is described theoretically and experimentally. The presented results constitute a basis for the design of multiband RoMMF systems, where spurious emission due to distortions should be compliant with wireless standards both in downlink and uplink.

Distortion Mechanisms Originating From Modal Noise in Radio Over Multimode Fiber Links

A comprehensive theoretical and experimental investigation is presented on the performances of cost-effective radio over fiber (RoF) links where the RoF Transmitter is directly modulated by signals complying the Universal Mobile Telecommunications Service (UMTS) and Worldwide Interoperability for Microwave Access (WiMAX) standards. A numerical model for calculating intermodulation related quantities like the adjacent channel leakage ratio has been developed for this purpose. Measurements have also been performed over real RoF Systems modulated by UMTS and WiMAX signals. A very good agreement has been found between measured and modelled results, and the feasibility of these connections over distances of tens of kilometers has been investigated.

Transmission of UMTS and WIMAX Signals Over Cost-Effective Radio Over Fiber Systems

Referring to short-range radio over multimode fiber links, we find out important guidelines for the realization of cost-effective intensity modulated directly detected systems. Since the quality of today's connectors is considerably higher than in the past, we demonstrate that two important parameters of the system are the finite detecting area of the photodiode and the laser frequency chirp. Furthemore, we show that the use of the central launch technique inherently determines a lower impact of modal noise fluctuations with respect to the offset launch one. This makes CL more convenient for short-range applications, where the transmittable bandwidth does not constitute the main limitation.

Pier Faccin

Papers

Distributed antenna system for MIMO signals

Distributed antenna system for mimo communications

Distortion Mechanisms Originating From Modal Noise in Radio Over Multimode Fiber Links

Transmission of UMTS and WIMAX Signals Over Cost-Effective Radio Over Fiber Systems

Link design rules for cost-effective short-range radio over multimode fiber systems