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Questions tagged [telecommunication]

Use this tag for questions about communications technology and its applications.

97 questions
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4 answers

Is interference between aircraft an issue for fly-by-wireless technology?

I was reading up on fly-by-wire development, and I saw a short section about fly-by-wireless technology. It seems like a great idea, with the potential to lower costs, weight and complexity. I can see a possible scenario where it could be an issue,…
HDE 226868
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1 answer

What is the difference between Bluetooth Low Energy and Bluetooth BR/EDR in Park mode?

It is known that Bluetooth Low Energy transmits data only during short time intervals called Connection Events. Connection events occur regullary with predefined period. The rest of the time Bluetooth LE device is does not transmit nor receive data.…
user1558573
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8
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1 answer

How were the tones for DTMF chosen?

In my limited engineering knowledge, and limited research skills, I couldn't find a complete answer for the reasoning behind the chosen tones for DTMF. I did find a hint that said something about resonance/interference, but that's not enough details…
natebot13
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8
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3 answers

Protecting device from microwaves in microwave oven.. but allowing Bluetooth?

I am building a device that needs to be inside of a microwave oven but somehow needs to communicate with another device outside of the microwave. How can I reflect microwaves so they don't come into contact with the electronics in the device, while…
Tyler
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7
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BER peroformance of MPSK and MQAM in Rayleigh fading channel

I have a question regarding bit error rate (BER) performance over the Rayleigh channel. I observed BER performance over the AWGN channel using Simulink in MATLAB. I used to change the "SNR" parameter in the AWGN block to get the BER. What if I want…
Sara
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7
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1 answer

Why does the LTE Specification define SC-FDMA as the modulation scheme for the reverse link?

The LTE specification specifies SC-FDMA as the encoding scheme for the reverse link (mobile to base station) when the forward link uses OFDMA. What is the reason for the difference?
psubsee2003
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How does LTE eNodeB set the Base Station output power?

I'm interested into the power radiated out of an eNodeB (LTE/4G) radio base station: which parameters does this power depend on, if they are constant or relying on the environment... All of this in order to be able to predict the rated power…
Amesys
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5
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1 answer

Why do bluetooth headsets get interference (choppy sound quality) outdoors?

This is more of a general physics question to help me understand how to choose sports headsets in the future, however it is too specific to a certain use case (bluetooth headset) to belong in the Physics StackExchange. Problem: 3 of my 4 sports…
allanlaal
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4
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LTE channel characterization from Time Domain waveform

I am currently interested into the diverse Downlink LTE channels broadcasted over air after some (QPSK, 16QAM...) modulation. More precisely their waveform. I would like to know if, with a good filtering of the noise, we could characterize the LTE…
Amesys
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Why downlink frequency is greater than uplink frequency in mobile communications?

Generally, downlink freq. > uplink freq. in mobile communications. I was able to gather some answers as to why is so. But my seniors (in my company) seem not to be satisfied with the below answers. High frequency means higher attenuation. So lets…
you_know_who
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3
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1 answer

signal-to-interference-plus-noise ratio (SINR) and others calculation

I am considering some empirical signal propagation models (like Hata, Ericsson models) to calculate 4 parameters: Path loss Received Signal Strength (RSS) signal-to-interference-plus-noise ratio Throughput Path loss is okay as each propagation…
Tana
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What are the pros and cons of between Zigbee and Z-Wave communication protocols used in IoT device space?

Recently, both Zigbee and Z-wave tend to be the most commonly used protocol to communicate between Internet of Things (IoT) devices. Most of these IoT devices tend to have a combination of mechanical or optical related transducer or actuator device…
Mahendra Gunawardena
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Viability of creating a wireless LAN bridge between mobiles and PCs using a portable router?

I am creating a network to share files between a mobile device and multiple PCs directly through a LAN. The purpose of which is to use smart phones to capture files from remote devices which are outside the range of the internet. The current plan is…
Luke
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3
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Wifi modulation and standard interoperability

I've been reading this summary(info.tek.com) of Wifi standards from Tektronix, which seems to do a pretty decent job of explaining things, but has left me with a couple of questions: For access points that support multiple standards, how are the…
TheLastBert
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How is modulated the Primary Synchronization Signal in LTE?

PSS is based on 62 values from a Zadoff-Chu sequence. Three different sequences can be used by an LTE Cell, to represent the Physical Cell ID within the Cell ID group. The formula is the following, $u$ being an index $[0;2]$ corresponding to a…
Amesys
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