The goal of Adaptive Modulation is to improve the operational efficiency of Microwave links by increasing network capacity over the existing infrastructure — while reducing sensitivity to environmental interferences. Adaptive Modulation means dynamically varying the modulation in an errorless manner in order to maximize the throughput under momentary propagation conditions.
In other words, a system can operate at its maximum throughput under clear sky conditions, and decrease it gradually under rain fade. This reduces the stress on the microwave power amplifiers, which reduces power consumption, heat generation and increases expected lifetime MTBF. Because of the scalability and flexibility of Microwave technology, Microwave products can be deployed in many enterprise applications including building-to-building connectivity, disaster recovery, network redundancy and temporary connectivity for applications such as data, voice and data, video services, medical imaging, CAD and engineering services, and fixed-line carrier bypass.
Microwave is far quicker to install and lower Total Cost of Ownership for Cellular Network Operators compared to deploying or leasing fibre optic networks. CableFree Low Latency versions of Microwave links uses Low Latency Technology, with absolutely minimal delay between packets being transmitted and received at the other end, except the Line of Sight propagation delay. You must be logged in to post a comment. Skip to content. Introduction to Microwave Example of a CableFree Microwave Link Installation Microwave is a line-of-sight wireless communication technology that uses high frequency beams of radio waves to provide high speed wireless connections that can send and receive voice, video, and data information.
Microwave Link over English Channel, In a US-French consortium demonstrated an experimental microwave relay link across the English Channel using 10 foot 3m dishes, one of the earliest microwave communication systems. Modern Commercial Microwave Links Microwave Communication Tower A microwave link is a communications system that uses a beam of radio waves in the microwave frequency range to transmit video, audio, or data between two locations, which can be from just a few feet or meters to several miles or kilometers apart.
For other definitions, see Letter Designations of Microwave Bands Lower Microwave frequencies are used for longer links, and regions with higher rain fade. Rain Fade on Microwave Links Rain fade refers primarily to the absorption of a microwave radio frequency RF signal by atmospheric rain, snow or ice, and losses which are especially prevalent at frequencies above 11 GHz. There is one set of equipment installed, and no diversity or backup Hot Standby : Two sets of microwave equipment ODUs, or active radios are installed generally connected to the same antenna, tuned to the same frequency channel.
If the active unit fails, it is powered down and the standby unit is activated. Frequency diversity : The signal is transmitted using several frequency channels or spread over a wide spectrum that is affected by frequency-selective fading.
Cordless phones may change their frequency each time they are used. Channel changes will be noticeable in the amplitude history or waterfall. Microwave ovens operate in the 2. Most people use a microwave oven in exact time lengths like 1 minute bursts, which are easily measured in the Waterfall View.
The amplitude levels of microwave oven leakage in the 2. Analog wireless security cameras generally create three spikes in the 2. They constantly transmit and rarely change channels. Look for three adjacent vertical lines in the Waterfall View. It is used primarily in automation and control settings with numerous nodes meshed on the same frequency. A wireless mouse can use standard or proprietary 2.
The frequency utilization is very low and the range of contention is minimal. Some headsets use proprietary 2. The Private Operational-Fixed Microwave Service can be used by persons eligible under Parts 80, 87 or 90 for communications related to their activities. Stations in this service are called operational-fixed to distinguish them from common carrier and public fixed stations. Private operational-fixed microwave systems serve many different purposes.
They are meant to carry or relay voice, teletype, telemetering, facsimile and digital communications associated with Aviation, Marine, Public Safety, Industrial, and the Land Transportation Radio Services. For example, these systems are used to operate unattended equipment; open and close switches or valves; record data like pressure, temperature, or speed of machines; telemeter voltage and current in power lines; and perform other control or monitoring functions.
Microwave systems are especially useful for controlling and monitoring various operations along installations like pipelines, railroads, and highways. Common Carrier microwave stations are generally used in a point-to-point configuration for long-haul backbone connections or to connect points on the telephone network which cannot be connected using standard wire line or fiber optic because of cost or terrain. These systems are also used to connect cellular sites to the telephone network, and to relay television signals.
Common Carrier microwave stations are licensed to applicants who intend to provide communications service to the public. Whereas, Private Operational Fixed stations are licensed to applicants for their own internal communications requirements. In electrical engineering, a transmission line is anything that conducts current from one point to another. Lamp cord, power lines, telephone wires and speaker cable are common transmission lines.
But at microwave frequencies, those media excessively weaken the signal. In their place, engineers use coaxial cables and, especially, hollow pipes called waveguides. The third part of the microwave system is the antennas. On the transmitting end, the antenna emits the microwave signal from the transmission line into free space. At the receiver site, an antenna pointed toward the transmitting station collects the signal energy and feeds it into the transmission line for processing by the receiver.
Antennas used in microwave links are highly directional, which means they tightly focus the transmitted energy, and receive energy mainly from one specific direction.
This contrasts with antennas used in many other communications systems, such as broadcasting. Since microwaves travel in essentially straight lines, man-made obstacles including possible future construction that might block the signal must either be overcome by tall antenna structures or avoided altogether. Natural obstacles also exist.
Flat terrain can create undesirable reflections, precipitation can absorb or scatter some of the microwave energy, and the emergence of foliage in the spring can weaken a marginally strong signal, which had been adequate when the trees were bare in the winter. Engineers must take all the existing and potential problems into account when designing a microwave link. At the end of the link is the final component, the receiver.
Here, information from the microwave signal is extracted and made available in its original form. To accomplish this, the receiver must demodulate the signal to separate the information from the microwave energy that carries it. The receiver must be capable of detecting very small amounts of microwave energy, because the signal loses much of its strength on its journey.
This entire process takes place at close to the speed of light, so transmission is virtually instantaneous even across long distances.
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